US 20050193537 A1
The present invention provides for a semiconductor workpiece processing tool and methods for handling semiconductor workpiece therein. The semiconductor workpiece processing tool preferably includes an interface section comprising at least one interface module and a processing section comprising a plurality of processing modules for processing the semiconductor workpieces. The semiconductor workpiece processing tool may have a conveyor for transferring the semiconductor workpieces between the interface modules and the processing modules.
5. A head assembly for holding a microelectronic workpiece in electrochemical processing, comprising:
a motor having a rotor axis;
a support coupled to the motor to rotate about the rotor axis, the support being configured to carry a microelectronic workpiece facedown in a workpiece processing plane generally normal to the rotor axis; and
a plurality of electrical contacts carried by the support, the electrical contacts having first sections outside of a workpiece zone where a workpiece is positioned relative to the support and second sections projecting from the first sections into a perimeter area of the workpiece zone, wherein individual second sections of the electrical contacts have (a) an inclined portion extending at an inclined angle relative to the workpiece processing plane and (b) a conductive contact region configured to press against a surface of the workpiece upon which electrochemical processing is to occur.
6. The head assembly of
7. The head assembly of
8. A tool for electrochemical processing of microelectronic workpieces, comprising:
a head assembly aligned with the chamber, the head assembly including a motor having a rotor axis, a support coupled to the motor to rotate about the rotor axis, and a plurality of electrical contacts carried by the support, wherein
the support is configured to carry a microelectronic workpiece facedown in a workpiece processing plane generally normal to the rotor axis, and
the contacts have first sections outside of a workpiece zone where a workpiece is positioned relative to the support and second sections projecting from the first sections, and wherein individual second sections of individual electrical contacts have (a) an inclined portion extending at an inclined angle relative to the workpiece processing plane and (b) a conductive contact region configured to press against a surface of the workpiece upon which electrochemical processing is to occur.
9. The tool of
10. The tool of
The present invention relates to tools for performing liquid and gaseous processing of semiconductor workpieces, and more particularly to tools which process semiconductor workpieces requiring low contaminant levels.
Semiconductor workpieces, such as wafers and the like, are the subject of extensive processing to produce integrated circuits, data disks and similar articles. During such processing it is often necessary to treat a particular workpiece or workpiece surface with either gaseous or liquid chemicals. Such treatment allows for films or layers of material to be deposited or grown on a workpiece surface. One method of accomplishing this is to expose the particular workpiece to desired processing environments in which desired chemicals are present to form or grow such films or layers. Some processing regimes involve moving the workpiece within the processing environment to effectuate film or layer coverage.
It has been increasingly desirable to minimize the size of features in integrated circuits during such processing to provide circuits having reduced size and increased integration and capacity. However, the reduction in feature size of such circuits is limited by contaminants such as particles, crystals, metals and organics which can cause defects and render the circuit inoperational. These limitations in feature size caused by contaminants have prevented utilization of full resolution capability of known processing techniques.
It is therefore highly desirable to conduct such semiconductor workpiece processing within a regulated environment which preferably involves some type of automated or computer controlled processing. The regulated environment has minimal human contact to provide a low contaminant environment. Providing a regulated environment reduces the chances of an inadvertent contamination which could render the workpiece useless.
Therefore, an increased need exists for providing a processing environment which adequately performs semiconductor workpiece processing steps in the presence of minimal contaminants.
Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are briefly described below.
This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).
Respective powered doors 35, 36 may be utilized to cover access ports 32, 33 thereby isolating the interior of the processing tool 10 from the clean room. Each door 35, 36 may comprise two portions. The upper portions and lower portion move upward and downward, respectively, into the front surface of the processing tool 10 to open ports 32, 33 and permit access therein.
Workpiece cassettes 16 are typically utilized to transport a plurality of semiconductor workpieces. The workpiece cassettes 16 are preferably oriented to provide the semiconductor workpieces therein in an upright or vertical position for stability during transportation of the semiconductor workpieces into or out of the processing tool 10.
The front outwardly facing surface of the processing tool 10 may advantageously join a clean room to minimize the number of harmful contaminants which may be introduced into the processing tool 10 during insertion and removal of workpiece cassettes 16. In addition, a plurality of workpiece cassettes 16 may be introduced into processing tool 10 or removed therefrom at one time to minimize the opening of ports 32, 33 and exposure of the processing tool 10 to the clean room environment.
The interface section 12 joins a processing section 14 of the processing tool 10. The processing section 14 may include a plurality of semiconductor workpiece processing modules for performing various semiconductor process steps. In particular, the embodiment of the processing tool 10 shown in
Alternatively, other modules for performing additional processing functions may also be provided within the processing tool 10 in accordance with the present invention. Pre-wet module 22 and resist strip module 24 define a second lateral surface of the processing tool 10. The specific processing performed by processing modules of the processing tool 10 may be different or of similar nature. Various liquid and gaseous processing steps can be used in various sequences. The processing tool 10 is particularly advantageous in allowing a series of complex processes to be run serially in different processing modules set up for different processing solutions. All the processing can be advantageously accomplished without human handling and in a highly controlled working space 11, thus reducing human operator handling time and the chance of contaminating the semiconductor workpieces.
The processing modules of the process tool 10 in accordance with the present invention are preferably modular, interchangeable, stand-alone units. The processing functions performed by the processing tool 10 may be changed after installation of the processing tool 10 increasing flexibility and allowing for changes in processing methods. Additional workpiece processing modules may be added to the processing tool 10 or replace existing processing modules 19.
The processing tool 10 of the present invention preferably includes a rear closure surface 18 joined with the lateral sides of the processing tool 10. As shown in
Each of the processing modules 20, 22, 24 may be advantageously accessed through the rear panel of the respective module forming the lateral side of the processing tool 10. The lateral sides of the processing tool 10 may be adjacent a gray room environment. Gray rooms have fewer precautions against contamination compared with the clean rooms. Utilizing this configuration reduces plant costs while allowing access to the processing components and electronics of each workpiece module 19 of the processing tool 10 which require routine maintenance.
A user interface 30 may be provided at the outwardly facing front surface of the processing tool as shown in
Each module 20, 22, 24 within the processing tool 10 preferably includes a window 34 allowing visual inspection of processing tool 10 operation from the gray room. Further, vents 37 may be advantageously provided within a top surface of each processing module 20, 22, 24. Processing module electronics are preferably located adjacent the vents 37 allowing circulating air to dissipate heat generated by such electronics.
The work space 11 within the interface section 12 and processing section 14 of an embodiment of the processing tool 10 is shown in detail in
The interface section 12 includes two interface modules 38, 39 for manipulating workpiece cassettes 16 within the processing tool 10. The interface modules 38, 39 receive workpiece cassettes 16 through the access ports 32, 33 and may store the workpiece cassettes 16 for subsequent processing of the semiconductor workpieces therein. In addition, the interface modules 38, 39 store the workpiece cassettes for removal from the processing tool 10 upon completion of the processing a of the semiconductor workpieces within the respective workpiece cassette 16.
Each interface module 38, 39 may comprise a workpiece cassette turnstile 40, 41 and a workpiece cassette elevator 42, 43. The workpiece cassette turnstiles 40, 41 generally transpose the workpiece cassettes 16 from a stable vertical orientation to a horizontal orientation where access to the semiconductor workpieces is improved. Each workpiece cassette elevator 42, 43 has a respective workpiece cassette support 47, 48 for holding workpiece cassettes 16. Each workpiece cassette elevator 42, 43 is utilized to position a workpiece cassette 16 resting thereon in either a transfer position and extraction position. The operation of the workpiece interface modules 38, 39 is described in detail below.
In a preferred embodiment of the present invention, the first workpiece interface module 38 may function as an input workpiece cassette interface for receiving unprocessed semiconductor workpieces into the processing tool 10. The second workpiece interface module 39 may function as an output workpiece cassette interface for holding processed semiconductor workpieces for removal from the processing tool 10. Workpiece transport units 62, 64 within the processing tool 10 may access workpiece cassettes 16 held by either workpiece interface module 38, 39. Such an arrangement facilitates transferring of semiconductor workpieces throughout the processing tool 10.
A semiconductor workpiece conveyor 60 is shown intermediate processing modules 20, 22, 24 and interface modules 38, 39 in
Workpiece conveyor. 60 advantageously includes a transport unit guide 66, such as an elongated rail, which defines a plurality of paths 68, 70 for the workpiece transport units 62, 64 within the processing tool 10. A workpiece transport unit 62 on a first path 68 may pass a workpiece transport unit 64 positioned on a second path 70 during movement of the transport units 62, 64 along transport guide 66. The processing tool 10 may include additional workpiece transport units to facilitate the transfer of semiconductor workpieces W between the workpiece processing modules 20, 22, 24 and workpiece interface modules 38, 39.
Each processing module 20, 22, 24 includes at least one semiconductor workpiece holder such as workpiece holder 810 located generally adjacent the workpiece conveyor 60. In particular, each of the workpiece transport units 62, 64 may deposit a semiconductor workpiece upon a semiconductor workpiece support 401 of the appropriate semiconductor processing module 20, 22, 24. Specifically, workpiece transport unit 64 is shown accessing an semiconductor workpiece support 401 of processing module 20. The workpiece transport units may either deposit or retrieve workpieces on or from the workpiece supports 401.
More specifically, the second arm extension 88 may support a semiconductor workpiece W via vacuum support 89. The appropriate workpiece transport unit 62, 64 may approach a workpiece support 401 by moving along transport unit guide 66. After reaching a proper location along guide 66, the first extension 87 and second extension 88 may rotate to approach the workpiece support 401. The second extension 88 is positioned above the workpiece support 401 and subsequently lowered toward engagement finger assemblies 409 on the workpiece support 401. The vacuum is removed from vacuum support 89 and finger assemblies 409 grasp the semiconductor workpiece W positioned therein. Second extension 88 may be lowered and removed from beneath the semiconductor workpiece held by the workpiece engagement fingers.
Following completion of processing of the semiconductor workpiece within the appropriate processing module 20, 22, 24, a workpiece transport unit 62, 64 may retrieve the workpiece and either deliver the workpiece to another processing module 20, 22, 24 or return the workpiece to a workpiece cassette 16 for storage or removal from the processing tool 10.
Each of the workpiece transport units 62, 64 may access a workpiece cassette 16 adjacent the conveyor 60 for retrieving a semiconductor workpiece from the workpiece cassette 16 or depositing a semiconductor workpiece therein. In particular, workpiece transport unit 62 is shown withdrawing a semiconductor workpiece W from workpiece cassette 16 upon elevator 42 in
More specifically, the second extension 88 and vacuum support 89 connected therewith may be inserted into a workpiece cassette 16 positioned in the extraction position. Second extension 88 and vacuum support 89 enter below the lower surface of the bottom semiconductor workpiece W held by workpiece cassette 16. A vacuum may be applied via vacuum support 89 once support 89 is positioned below the center of the semiconductor workpiece W being removed. The second extension 88, vacuum support 89 and semiconductor workpiece W attached thereto may be slightly raised via transfer arm elevator 90. Finally, first extension 87 and second extension 88 may be rotated to remove the semiconductor workpiece W from the workpiece cassette 16. The workpiece transport unit 62, 64 may thereafter deliver the semiconductor workpiece W to a workpiece processing module 19 for processing.
Thereafter, workpiece transport unit 62 may travel along path 68 to a position adjacent an appropriate processing module 20, 22, 24 for depositing the semiconductor workpiece upon workpiece processing support 401 for processing of the semiconductor workpiece.
Preferably, the first workpiece interface module 38 and the second workpiece interface module 39 may function as a respective semiconductor workpiece cassette 16 input module and output module of the processing tool 10. Alternately, both modules can function as both input and output. More specifically, workpiece cassettes 16 holding unprocessed semiconductors workpieces may be brought into the processing tool 10 via port 32 and temporarily stored within the first workpiece interface module 38 until the semiconductor workpieces are to be removed from the workpiece cassette 16 for processing. Processed semiconductor workpieces may be delivered to a workpiece cassette 16 within the second workpiece interface module 39 via workpiece transport units 62, 64 for temporary storage and/or removal from the processing tool 10.
The workpiece interface modules 38, 39 may be directly accessed by each of the workpiece transport units 62, 64 within the processing tool 10 for transferring semiconductor workpieces therebetween. Providing a plurality of workpiece cassette interface modules 38, 39 accessible by each workpiece transport unit 62, 64 facilitates the transport of semiconductor workpieces W throughout the processing tool 10 according to the present invention.
Each workpiece interface module 38, 39 preferably includes a workpiece cassette turnstile 40 and a workpiece cassette elevator 42 adjacent thereto. The access ports 32, 33 are adjacent the respective workpiece cassette turnstiles 40, 41. Workpiece cassettes 16 may be brought into the processing tool 10 or removed therefrom via ports 32, 33.
Workpiece cassettes 16 are preferably placed in a vertical position onto cassette Frays 50 prior to delivery into the processing tool 10. Cassette trays 50 are shown in detail in
Each workpiece cassette turnstile 40, 41 preferably includes two saddles 45, 46 each configured to hold a workpiece cassette 16. Providing two saddles 45, 46 enables two workpiece cassettes 16 to be placed into the processing tool 10 or removed therefrom during a single opening of a respective access door 35, 36 thereby minimizing exposure of the workspace 11 within the processing tool 10 to the clean room environment.
Each saddle 45, 46 includes two forks engageable with the cassette tray 50. Saddles 45, 46 are powered by motors within the workpiece cassette turnstile shaft 49 to position the workpiece cassette 16 in a horizontal or vertical orientation. The workpiece cassettes 16 and semiconductor workpieces therein are preferably vertically oriented for passage through the access ports 32, 33 and horizontally oriented in a transfer or extraction position to provide access of the workpieces therein to the workpiece transport units 62, 64.
The workpiece cassette 16 held by workpiece cassette turnstile 40 in
The workpiece cassette turnstile 41 and workpiece cassette elevator 42 may exchange workpiece cassettes 15, 17 to transfer a workpiece cassette 17 having processed semiconductor workpieces therein from the extraction position to the hold position for removal from the processing tool 10. Additionally, such an exchange may transfer a workpiece cassette 15 having unprocessed semiconductor workpieces therein from the hold position to the extraction position providing workpiece transport units 62, 64 with access to the semiconductor workpiece therein.
The exchange of workpiece cassettes 15, 17 is described with reference to
Workpiece cassette 17 having processed semiconductor workpieces therein is now accessible via port 32 for removal from the processing tool 10. Workpiece cassette 15 having unprocessed semiconductors therein is now positioned for engagement with workpiece cassette support 47. The transfer process steps shown in
Workpiece Cassette Tray
A workpiece cassette tray 50 for holding a workpiece cassette 16 is shown in detail in
The workpiece cassette trays 50 are preferably utilized during the handling of workpiece cassettes 16 within the workpiece cassette interface modules 38, 39 where the workpiece cassettes 16 are transferred from a load position to an extraction position providing access of the semiconductor workpieces W to workpiece transport units 62, 64 within the conveyor 60.
Semiconductor Workpiece Conveyor
The processing tool 10 in accordance with the present invention advantageously provides a semiconductor workpiece conveyor 60 for transporting semiconductor workpieces throughout the processing tool 10. Preferably, semiconductor workpiece conveyor 60 may access each workpiece cassette interface module 38, 39 and each workpiece processing module 19 within processing tool 10 for transferring semiconductor workpieces therebetween. This includes processing modules from either side.
One embodiment of the workpiece conveyor 60 is depicted in
Workpiece transport unit guide 66 defines the paths of movement 68, 70 of workpiece transport units 62, 64 coupled therewith. Referring to
It is to be understood that workpiece conveyor 60 may be formed in alternate configurations dependent upon the arrangement of interface modules 38, 39 and processing modules 20, 22, 24 within the processing tool 10. Ducts 58, 59 are preferably in fluid communication with extensions from each workpiece processing module 19 and an exhaust fan for removing circulated air from the workspace 11 of the processing tool 10.
Each workpiece transport unit 62, 64 is powered along the respective path 68, 70 by a suitable driver. More specifically, drive operators 71, 74 are advantageously mounted to respective sides of transport unit guide 66 to provide controllable axial movement of workpiece transport units 62, 64 along the transport unit guide 66.
The drive operators 71, 74 may be linear magnetic motors for providing precise positioning of workpiece transport units 62, 64 along guide 66. In particular, drive operators 71, 74 are preferably linear brushless direct current motors. Such preferred driver operators 71, 74 utilize a series of angled magnetic segments which magnetically interact with a respective electromagnet 79 mounted on the workpiece transport units 62, 64 to propel the units along the transport unit guide 66.
Cable guards 72, 73 may be connected to respective workpiece transport units 62, 64 and frame 65 for protecting communication and power cables therein. Cable guards 72, 73 may comprise a plurality of interconnected segments to permit a full range of motion of workpiece transport units 62, 64 along transport unit guide 66.
As shown in
Semiconductor Workpiece Transport Units
Preferred embodiments of the semiconductor workpiece transport units 62, 64 of the workpiece conveyor 60 are described with reference to
In general, each workpiece transport unit 62, 64 includes a movable carriage or tram 84 coupled to a respective side of the transport unit guide 66, a workpiece transfer arm assembly 86 movably connected to the tram 84 for supporting a semiconductor workpiece W, and a workpiece transfer arm elevator 90 for adjusting the elevation of the transfer arm assembly 86 relative to tram 84.
A workpiece transfer arm assembly 86 extends above the top of tram 84. The workpiece transfer arm assembly 86 may include a first arm extension 87 coupled at a first end thereof with a shaft 83. A second arm extension 88 may be advantageously coupled with a second end of the first extension 87. The first arm extension 87 may rotate 360 degrees about shaft 83 and second arm extension 88 may rotate 360 degrees about axis 82 passing through a shaft connecting first and second arm extensions 87, 88.
Second extension 88 preferably includes a wafer support 89 at a distal end thereof for supporting a semiconductor workpiece W during the transporting thereof along workpiece conveyor 60. The transfer arm assembly 86 preferably includes a chamber coupled with the workpiece support 89 for applying a vacuum thereto and holding a semiconductor workpiece W thereon.
Providing adjustable elevation of transfer arm assembly 86, rotation of first arm extension 87 about the axis of shaft 83, and rotation of second extension 88 about axis 82 allows the transfer arm 86 to access each semiconductor workpiece holder 810 of all processing modules 19 and each of the wafer cassettes 16 held by interface modules 38, 39 within the processing tool 10. Such access permits the semiconductor workpiece transport units 62, 64 to transfer semiconductor workpieces therebetween.
The cover 85 has been removed from the workpiece transport unit 62, 64 shown in
The path position of the tram 84 of each workpiece transport unit 62, 64 along the transport unit guide 66 is precisely controlled using a positional indicating array, such as a CCD array 91 of
The transfer arm assembly 86 includes an CCD array 91 positioned to receive the laser beam generated by light emitter 81. A position indicating array 91 on shaft 83 detects the presence of the light beam to determine the location of tram 84 along transport unit guide 66. The positional accuracy of the workpiece transport unit position indicator is preferably in the range less than 0.003 inch (approximately less than 0.1 millimeter).
Control System Generally
The control system 100 is preferably arranged in a hierarchial configuration. The grand master controller 101 includes a processor electrically coupled with a plurality of subsystem control units as shown in
More specifically, the grand master control 101 is coupled with an interface module control 110 which may control each of the semiconductor workpiece interface modules 38, 39. Further, grand master control 101 is coupled with a conveyor control 113 for controlling operations of the workpiece conveyor 60 and a plurality of processing module controls 114, 115 corresponding to semiconductor workpiece processing modules 20, 22 within the processing tool 10.
The control system 100 of the processing tool 10 according to the present invention may include additional grand master controllers 102 as shown in
Each grand master controller 101, 102 receives and transmits data to the respective modular control subsystems 110-119. In a preferred embodiment of the control system 100, a bidirectional memory mapped device is provided intermediate the grand master controller and each modular subsystem connected thereto. In particular, memory mapped devices 160, 161, 162 are provided intermediate the grand master controller 101 and master controllers 130, 131, 132 within respective interface module control 110, workpiece conveyor control 113 and processing module control 114.
Each memory mapped device 150, 160-162 within the control system 100 is preferably a dual port RAM provided by Cypress for asynchronouosly storing data. In particular, grand master controller 101 may write data to a memory location corresponding to master controller 130 and master controller 130 may simultaneously read the data. Alternatively, grand master controller 101 may read data from mapped memory device being written by the master controller 130. Utilizing memory mapped devices 160-161 provides data transfer at processor speeds. Memory mapped device 150 is preferably provided intermediate interface 30 and the grand master controllers 101, 102 for transferring data therebetween.
A user interface 30 is preferably coupled with each of the grand master controllers 101, 102. The user interface 30 may be advantageously mounted on the exterior of the processing tool 10 or at a remote location to provide an operator with processing and status information of the processing tool 10. Additionally, an operator may input control sequences and processing directives for the processing tool 10 via user interface 30. The user interface 30 is preferably supported by a general purpose computer within the processing tool 10. The general purpose computer preferably includes a 486 100 MHz processor, but other processors may be utilized.
Each modular control subsystem, including interface module control 110, workpiece conveyor control 113 and each processing module control 114-119, is preferably configured in a master/slave arrangement. The modular control subsystems 110, 113-119 are preferably housed within the respective module such as workpiece interface module 38, 39, workpiece conveyor 60, or each of the processing modules 20, 22, 24. The grand master controller 101 and corresponding master controllers 130, 131, 132 coupled therewith are preferably embodied on a printed circuit board or ISA board mounted within the general purpose computer supporting user interface 30. Each grand master controller 101, 102 preferably includes a 68EC000 processor provided by Motorola and each master controller 130 and slave controller within control system 100 preferably includes a 80251 processor provided by Intel.
Each master controller 130, 131, 132 is coupled with its respective slave controllers via a data link 126, 127, 129 as shown in
The grand master controller 101 is connected via memory mapped device 160 to a master controller 130 within the corresponding interface module control 110. The master controller 130 is coupled with a plurality of slave controllers 140, 141, 142. Sixteen slave controllers may be preferably coupled with a single master controller 130-132 and each slave controller may be configured to control and monitor a single motor or process component, or a plurality of motors and process components.
The control system 100 of the processing tool 10 preferably utilizes flash memory. More specifically, the operation instructions or program code for operating each master controller 130-132 and slave controller 140-147 within the control system 100 may be advantageously stored within the memory of the corresponding grand master controller 101, 102. Upon powering up, the grand master controller 101, 102 may poll the corresponding master controllers 130-132 and download the appropriate operation instruction program to operate each master controller 130-132. Similarly, each master controller 130-132 may poll respective slave controllers 140-147 for identification. Thereafter, the master controller 130-132 may initiate downloading of the appropriate program from the grand master controller 101, 102 to the respective slave controller 140-147 via the master controller 130-132.
Each slave controller may be configured to control and monitor a single motor or a plurality of motors within a corresponding processing module 19, interface module 38, 39 and workpiece conveyor 60. In addition, each slave controller 140-147 may be configured to monitor and control process components 184 within a respective module 19. Any one slave controller, such as slave controller 145 shown in
Each slave controller includes a slave processor which is coupled with a plurality of port interfaces. Each port interface may be utilized for control and/or monitoring of servo motors and process components 184. For example, a port may be coupled with a servo controller card 176 which is configured to operate a workpiece transfer unit 62, 64. The slave processor 171 may operate the workpiece transfer unit 62, 64 via the port and servo controller 176. More specifically, the slave processor 171 may operate servo motors within the workpiece transfer unit 62, 64 and monitor the state of the motor through the servo controller 176.
Alternatively, different slave controllers 140, 141 may operate different components within a single processing tool device, such as interface module 38. More specifically, the interface module control 110 and components of the interface module 38 are depicted in
A port of a slave processor may be coupled with an interface controller card 180 for controlling and monitoring process components within a respective processing module 19. For example, a flow sensor 657 may provide flow information of the delivery of processing fluid to a processing bowl within the module. The interface controller 180 is configured to translate the data provided by the flow sensors 657 or other process components into a form which may be analyzed by the corresponding slave processor 172. Further, the interface controller 180 may operate a process component, such as a flow controller 658, responsive to commands from the corresponding slave processor 172.
One slave controller 140-147 may contain one or more servo controller and one or more interface controller coupled with respective ports of the slave processor 170-172 for permitting control and monitor capabilities of various component motors and processing components from a single slave controller.
Alternatively, a servo controller and interface controller may each contain an onboard processor for improving the speed of processing and operation. Data provided by an encoder or process component to the servo controller or interface controller may be immediately processed by the on board processor which may also control a respective servo motor or processing component responsive to the data. In such a configuration, the slave processor may transfer the data from the interface processor or servo controller processor to the respective master controller and grand master controller.
Conveyor Control Subsystem
The conveyor control subsystem 113 for controlling and monitoring the operation of the workpiece conveyor 60 and the workpiece transport units 62, 64 therein is shown in
The interfacing of slave controller 143 and light detector 91, drive actuator 71, linear encoder 196 and workpiece transport unit 62 is shown in detail in
The conveyor slave processor 171 may also control and monitor the operation of the transfer arm assembly 86 of the corresponding workpiece transport unit 62. Specifically, the conveyor processor 171 may be coupled with a transfer arm motor 194 within shaft 83 for controllably rotating the first and second arm extensions 87, 88. An incremental transfer arm rotation encoder 197 may be provided within the shaft 83 of each workpiece transport unit 62 for monitoring the rotation of transfer arm assembly 86 and providing rotation data thereof to servo controller 176 and slave processor 171.
Slave controller 143 may be advantageously coupled with transfer arm elevation motor 195 within elevator 90 for controlling the elevational position of the transfer arm assembly 86. An incremental transfer arm elevation encoder 198 may be provided within the transfer arm elevator assembly 90 for monitoring the elevation of the transfer arm assembly 86.
In addition, conveyor slave controller 143 may be coupled with an air supply control valve actuator (not shown) via an interface controller for controlling a vacuum within wafer support 89 for selectively supporting a semiconductor workpiece thereon.
Absolute encoders 199 may be provided within the workpiece conveyor 60, interface modules 38, 39 and processing modules 19 to detect extreme conditions of operation and protect servo motors therein. For example, absolute encoder 199 may detect a condition where the transfer arm assembly 86 has reached a maximum height and absolute encoder 199 may turn off elevator 90 to protect transfer arm elevator motor 195.
Processing Module Control
The control system 100 preferably includes a processing module control subsystem 114-116 corresponding to each workpiece processing module 20, 22, 24 within the processing tool 10 according to the present invention. The control system 100 may also include additional processing module control subsystem 119 for controlling and/or monitoring additional workpiece processing modules 19.
Respective processing module controls 114, 115, 116 may control and monitor the transferring of semiconductor workpieces W between a corresponding workpiece holder 810 and workpiece transport unit 62, 64. Further, processing module controls 114, 115, 116 may advantageously control and/or monitor the processing of the semiconductor workpieces W within each processing module 20, 22, 24.
In addition, a single slave controller 145-148 may be configured to operate and monitor one or more workpiece holder 401 and processing components 184. The interfacing of a slave controller 145 to both a workpiece holder 401 and process components is shown in the control system embodiment in
Slave processor 172 may operate and monitor a plurality of workpiece holder components via servo controller 177. In particular, slave processor 172 may operate lift motor 427 for raising operator arm 407 about lift drive shaft 456. An incremental lift motion encoder 455 may be provided within a workpiece holder 401 to provide rotational information of lift arm 407 to the respective slave processor 172 or a processor within servo controller 177. Slave processor 172 may also control a rotate motor 428 within workpiece holder 401 for rotating a processing head 406 about shafts 429, 430 between a process position and a semiconductor workpiece transfer position. Incremental rotate encoder 435 may provide rotational information regarding the processing head 406 to the corresponding slave processor 172.
Spin motor 480 may also be controlled by a processor within servo controller 177 or slave processor 172 for rotating the workpiece holder 478 during processing of a semiconductor workpiece W held thereby. An incremental spin encoder 498 is preferably provided to monitor the rate of revolutions of the workpiece holder 478 and supply the rate information to the slave processor 172.
Plating module control 114 advantageously operates the fingertips 414 of the workpiece holder 478 for grasping or releasing a semiconductor workpiece. In particular, slave processor 172 may operate a valve via pneumatic valve actuator 201 for supplying air to pneumatic piston 502 for actuating fingertips 414 for grasping a semiconductor workpiece. The slave controller 145 within the plating module control 114 may thereafter operate the valve actuator 201 to remove the air supply thereby disengaging the fingertips 414 from the semiconductor workpiece. Slave processor 172 may also control the application of electrical current through the finger assembly 824 during the processing of a semiconductor workpiece by operating relay 202.
The processing module controls 114, 115, 116 preferably operate and monitor the processing of semiconductor workpieces within the corresponding workpiece processing modules 20, 22, 24 via instrumentation or process components 184.
Similarly, processing module control subsystems 115, 116 may be configured to control the processing of semiconductor workpieces within the corresponding prewet module 22 and resist module 24.
Interface Module Control
Each interface module control subsystem 110 preferably controls and monitors the operation of workpiece interface modules 38, 39. More specifically, interface module control 110 controls and monitors the operation of the workpiece cassette turnstiles 40, 41 and elevators 42, 43 of respective semiconductor workpiece interface modules 38, 39 to exchange workpiece cassettes 16.
Slave processor 170 within slave controller 140 of interface module control 110 may operate and monitor the function of the interface modules 38, 39. In particular, slave processor 170 may operate doors 35, 36 for providing access into the processing tool 10 via ports 32, 33. Alternatively, master control 100 may operate doors 35, 36.
Each workpiece cassette turnstile 40 includes a motor for controlling the positioning of saddles 45, 46 connected thereto. The slave processor 170 may control the position of saddles 45, 46 through operation of the appropriate saddle motor 186 to orient workpiece cassettes 16 attached thereto in one of a vertical and horizontal orientation. Incremental saddle encoders 191 are preferably provided within each workpiece cassette turnstile 40 for providing position information of the saddles 45, 46 to the respective slave processor 170.
Either slave processor 170 or servo controller 175 may be configured to control the operation of the workpiece cassette elevator 42 for transferring a workpiece cassette 16 between either the exchange position and the extraction position. The slave processor 170 may be coupled with an elevator lift motor 187 and elevator rotation motor 188 for controlling the elevation and rotation of elevator 42 and elevator support 47. Incremental lift encoder 192 and incremental rotation encoder 193 may supply elevation and rotation information of the elevator 42 and support 47 to slave processor 170.
Absolute encoders 199 may be utilized to notify slave processor of extreme conditions such as when elevator support 47 reaches a maximum height. Elevator lift motor 187 may be shut down in response to the presence of an extreme condition by absolute encoder 199.
Additional aspects of this invention include novel methods of handling semiconductor workpieces W within a semiconductor workpiece processing tool 10. The method of handling semiconductor workpieces within a processing tool 10 having at least one workpiece processing module 19 and a workpiece conveyor 60 includes a step of receiving a workpiece cassette 16 having a plurality of semiconductor workpieces W therein into the workpiece processing tool 10. The method additionally includes steps of simultaneously moving a first and second workpiece transport unit 62, 64 along the workpiece conveyor 60 to simultaneously transport individual semiconductor workpieces W between the workpiece cassettes 16 and processing modules 19.
The workpiece cassette 16 may be preferably translated or otherwise reoriented between an approximately vertical orientation and an approximately horizontal orientation within the workpiece processing tool 10. Specifically, each workpiece cassette 16 and the semiconductor workpieces W therein are preferably oriented in a vertical position during the step of loading the workpiece cassette 16 into the processing tool 10 or removing a workpiece cassette 16 therefrom. The workpiece cassettes 16 and semiconductor workpieces therein are preferably oriented in a horizontal position during the step of extracting semiconductor workpieces W from the workpiece cassette 16. Further, a plurality of workpiece cassettes 16 may be stored within the processing tool 10 to limit the exposure of the workspace 11 of the processing tool 10 to the surrounding clean room environment.
The methods can also preferably provide for introducing unprocessed semiconductor workpieces into a first interface module 38 for storage. Workpiece transport units 62, 64 may access the unprocessed semiconductor workpieces within a workpiece cassette 16 held by the first interface module 38. Processed semiconductor workpieces are preferably placed into workpiece cassettes 16 held within the output processing module 39 for removal from the processing tool 10.
The present invention additionally provides for a method of handling semiconductor workpieces W within a processing tool 10 having a plurality of workpiece processing modules 19 adjacent opposing sides of a workpiece conveyor 60. The processing modules are preferably along both sides and are accessible by transport units from either side of conveyor 60. In particular, the method comprises the steps of receiving a workpiece cassette 16 into the processing tool 10 and storing the workpiece cassette 16 therein. The semiconductor workpieces may be individually transferred via the workpiece conveyor 60 to selected workpiece processing modules 19.
The method may include a translation step where the semiconductor workpiece cassettes 16 are advantageously positioned in a vertical orientation for stability during the receiving step and in a horizontal orientation during an extraction step to facilitate access to the semiconductor workpieces within a respective workpiece cassette 16. The workpiece transport units 62, 64 may access each workpiece processing module 19 adjacent opposing sides of the workpiece conveyor 60 to transfer the semiconductor workpieces therebetween. Preferably, each workpiece transport unit 62, 64 travels along paths defined by the workpiece conveyor 60.
The method preferably provides for introducing unprocessed semiconductor workpieces into a first interface module 38 for storage and placing processed semiconductor workpieces into workpiece cassettes 16 held within the output processing module 39 for temporary storage and removal from the processing tool 10.
Turning now to
Turning now to
The processing head is advantageously rotatable about processing head pivot axis or, more briefly termed, process pivot axis 411. In this manner, a workpiece (not shown) may be disposed between and grasped by the fingers 409, at which point the processing head is preferably rotated about process head pivot axis 411 to place the workpiece in a position to be exposed to the manufacturing process.
In the preferred embodiment, operator arm 407 may be pivoted about operator pivot axis 412. In this manner, the workpiece is advantageously lowered into the process bowl (not shown) to accomplish a step in the manufacture of the semiconductor wafer.
Turning now to
Once the workpiece W has been securely engaged by fingertips 414, processing head 406 can be rotated about process head pivot axis 411 as shown in
Since the processing head 406 is engaged by the operator arm 407 on the left and right side by the preferably horizontal axis 411 connecting the pivot points of processing head 406, a high degree of stability about the horizontal plane is obtained. Further, since the operator arm 407 is likewise connected to the operator base 405 at left and right sides along the essentially horizontal line 412 connecting the pivot points of the operator arm, the workpiece support forms a structure having high rigidity in the horizontal plane parallel to and defined by axes 411 and 412. Finally, since operator base 405 is securely attached to the semiconductor process machine 400, rigidity about the spin axis 410 is also achieved.
Similarly, since processing head 406 is nested within the fork or yoke shaped operator arm 407 having left and right forks 418 and 419, respectively, as shown in
In a typical semiconductor manufacturing process, the workpiece holder 408 will rotate the workpiece, having the process head 406 secured at two points, that is, at the left and right forks 418 and 419, respectively, the vibration induced by the rotation of the workpiece holder 408 will be significantly reduced along the axis 411.
A more complete description of the components of the present invention and their operation and interrelation follows.
Turning now to
The upper portions of the yoke arm advantageously include receptacles for housing the operator arm bearings 424 which are used to support the pivot shafts of the operator arm 425, described more fully below.
Operator arm or pivot arm 407 is advantageously constructed in such a manner to reduce mass cantilevered about operator arm pivot axis 412. This allows for quicker and more accurate positioning of the pivot arm as it is moved about pivot arm axis 412.
The left fork of the pivot arm 418, shown more clearly in
The process arm rear cavity 426, shown in
Operator arm 407 is securely attached to left yoke arm 421 and right yoke arm 422 by operator arm pivot shafts 425 and operator arm pivot bearings 424, the right of which such bearing shaft and bearings are shown in
Operator Arm-Processing Head Rotate Mechanism
Turning now to
Rotate motor 428 is disposed within process arm rear cavity 426 and is supported by rotate motor support 434. Rotate motor 428 preferably is a servo allowing for accurate control of speed and acceleration of the motor. Servo motor 428 is advantageously connected to rotate encoder 435 which is positioned on one end of rotate motor 428. Rotate encoder 435, more generally described as processing head encoder, allows for accurate measurement of the number of rotations of rotate motor 428, as well as the position, speed, and acceleration of the rotate shaft 432. The information from the rotate encoder may be used in a rotate circuit which may then be used to control the rotate motor when the rotate motor is a servo. This information is useful in obtaining the position and rate of travel of the processing head, as well as controlling the final end point positions of the processing head as it is rotated about process head rotate axis 411.
The relationship between the rotate motor rotations, as measured by rotate encoder 435, may easily be determined once the diameters of the rotate pulley 425 and the processing head pulley 438 are known. These diameters can be used to determine the ratio of rotate motor relations to processing head rotations. This may be accomplished by a microprocessor, as well as other means.
Rotate pulley 425 is further supported within operator arm 407 by rotate pulley inboard bearing 436 which is disposed about an extended flange on the rotate pulley 425. Rotate pulley inboard bearing 436 is secured by the body of the operator arm 407, as shown in
Rotate pulley 425 advantageously drives rotate belt 437, more generally described as a flexible power transmission coupling. Referring now to
Rotate mechanism 431 is preferably provided with rotate belt tensioner 439, useful for adjusting the belt to take up slack as the belt may stretch during use, and to allow for adjustment of the belt to assure positive engagement with both the rotate pulley and the processing head pulley. Rotate belt tensioner 439 adjusts the tension of rotate belt 437 by increasing the length of the belt path between rotate pulley 425 and processing head pulley 438, thereby accommodating any excess lengths in the belt. Inversely, the length of the belt path may also be shortened by adjusting rotate belt tensioner 439 so as to create a more linear path in the upper portion of rotate belt 437. The tensioner 439 is adjusted by rotating it about tensioner hub 468 and securing it in a new position.
Turning now to
Processing head pivot shafts 430 and 429 are advantageously hollow shafts. This feature is useful in allowing electrical, optical, pneumatic, and other signal and supply services to be provided to the processing head. Service lines such as those just described which are routed through the hollow portions of processing head pivot shafts 429 and 430 are held in place in the operator arms by cable brackets 442 and 443. Cable brackets 442 and 443 serve a dual purpose. First, routing the service lines away from operating components within the operator arm left and right forks. Second, cable brackets 442 and 443 serve a useful function in isolating forces imparted to the service cables by the rotating action of processing head 406 as it rotates about processing head pivot shafts 429 and 430. This rotating of the processing head 406 has the consequence that the service cables are twisted within the pivot shafts as a result of the rotation, thereby imparting forces to the cables. These forces are preferably isolated to a particular area so as to minimize the effects of the forces on the cables. The cable brackets 442 and 443 achieve this isolating effect.
The process head rotate mechanism 431, shown in
Operator Arm-Lift Mechanism
Operator arm 407 is also advantageously provided with an operator arm lift mechanism 448 which is useful for causing the operator arm to lift, that is, to pivot or rotate about operator arm pivot axis 412. Turning to
Operator arm lift mechanism 448 is advantageously driven by lift motor 452. Lift motor 452 may be more generally described as an operator arm drive or operator arm pivot drive. Lift motor 452 is preferably a servo motor and is more preferably provided with an operator encoder, more specifically described as lift motor encoder 456. When lift motor 452 is a servo motor coupled with lift encoder 456, information regarding the speed and absolute rotational position of the lift motor shaft 454 may be known from the lift encoder signal. Additionally, by virtue of being a servo mechanism, the angular speed and acceleration of lift motor 452 may be easily controlled by use of the lift signal by an electrical circuit. Such a lift circuit may be configured to generate desired lift characteristics (speed, angle, acceleration, etc.).
Lift motor 452 drives lift motor shaft 454 which in turn drives lift gear drive 453. Lift gear drive 453 is a gear reduction drive to produce a reduced number of revolutions at lift drive shaft 456 as the function of input revolutions from lift motor shaft 454.
Lift drive gear shaft 456 is secured to lift anchor 451 which is more clearly shown in
In operation, as lift motor 452 causes lift gear drive 453 to produce rotations at gear drive shaft 456, lift anchor 451 is forced against lift bushing 449 which is securely positioned within right operator yoke arm 421. The reactive force against the lift anchor 451 will cause lift bearing support 460 to rotate relative to lift bushing 449. Since lift bushing 449 is fixed in operator base 405, and since operator base 405 is fixed to processing machine 400, rotation of lift bearing support 460 will cause lift arm 407 to pivot about operator arm pivot axis 412, thereby moving the processing head 406. It is advantageous to consider the gear drive shaft (or “operator arm shaft”) as being fixed with respect to operator base 405 when envisioning the operation of the lift mechanism.
Operator lift mechanism 448 is also advantageously provided with a lift overtravel protect 462 or lift switch. The lift rotate protect operates in a manner similar to that described for the rotate overtravel protect 444 described above. Turning now to
The lift overtravel protect preferably includes a lift optical switch low 463 and a lift optical switch high 464. Other types of limit switches can also be used. The switch high 464 and switch low 463 correspond to beginning and endpoint travel of lift arm 407. The primary lift switch component is lift flag 465, which is firmly attached to left operator base yoke arm 421. The lift optical switches are preferably mounted to the movable operator arm 407. As operator arm 407 travels in an upward direction in pivoting about operator arm pivot axis 412, lift optical switch high 464 will approach the lift flag 465. Should the lift motor encoder 455 fail to stop the lift motor 454 as desired, the lift flag 465 will break the optical path of the lift optical switch high 464 thus producing a signal which can be used to stop the lift motor. In like manner, when the operator arm 407 is being lowered by rotating it in a clockwise direction about the operator arm pivot axis 412, as shown in
Turning now to
The sides of processing head housing 470 are advantageously provided with rotate shaft openings 474 and 475 for receiving respectively left and right processing head pivot shafts 429 and 430. Processing head pivot shafts 429 and 430 are secured to the processing head 406 by respective left and right processing head mounts 472 and 473. Processing head mounts 472 and 473 are affirmative connected to processing head frame 582 which also supports processing head door 476 which is itself securely fastened to processing head housing 470. Consequently, processing head pivot shafts 429 and 430 are fixed with respect to processing head 407 and may therefore rotate or pivot with respect to operator arm 407. The details of how processing head pivot shafts 429 and 430 are received within operator arm 407 were discussed supra.
Processing head housing 470 forms a processing head void 477 which is used to house additional processing head components such as the spin motor, the pneumatic finger actuators, and service lines, all discussed more fully below.
The processing head also advantageously includes a workpiece holder and fingers for holding a workpiece, as is also more fully described below.
Processing Head Spin Motor
In a large number of semiconductor manufacturing processes, is desirable to spin the semiconductor wafer or workpiece during the process, for example to assure even distribution of applied process fluids across the face of the semiconductor wafer, or to aid drying of the wafer after a wet chemistry process. It is therefore desirable to be able to rotate the semiconductor workpiece while it is held by the processing head.
The semiconductor workpiece is held during the process by workpiece holder 478 described more fully below. In order to spin workpiece holder 478 relative to processing head 406 about spin axis 479, an electric, pneumatic, or other type of spin motor or workpiece spin drive is advantageously provided.
The spin motor is preferably an electric motor which is provided with an electrical supply source through pivot shaft 429 and/or 430. Spin motor 480 will drive spin motor shaft 483 about spin axis 479.
To secure workpiece holder rotor 484 to spin motor shaft 483, workpiece holder rotor 484 is preferably provided with a rotor hub 485. Rotor hub 485 defines a rotor hub recess 486 which receives a flared end of workpiece holder shaft 491. The flared end 487 of workpiece holder shaft 491 is secured within the rotor hub recess 486 by workpiece shaft snap-ring 488 which fits within rotor recess groove 489 above the flared portion 487 of workpiece holder shaft 491.
The workpiece holder shaft 491 is fitted inside of spin motor shaft 483 and protrudes from the top of the spin motor shaft. The top of workpiece holder shaft 491 is threaded to receive thin nut 527 (see
Workpiece holders may be easily changed out to accommodate various configurations which may be required for the various processes encountered in manufacturing of the semiconductors. This is accomplished by removing spin encoder 498 (described below), and then thin nut 527. Once the thin nut has been removed the workpiece holder 478 will drop away from the processing head 406.
The processing head is also advantageously provided with a spin encoder 498, more generally described as a workpiece holder encoder, and an optical tachometer 499. As shown in
In one application of the present invention the workpiece support is used to support a semiconductor workpiece in an electroplating process. To accomplish the electroplating an electric current is provided to the workpiece through an alternate embodiment of the fingers (described more fully below). To provide electric current to the finger, conductive wires are run from the tops of the fingers inside of the workpiece holder 478 through the electrode wire holes 525 in the flared lower part of workpiece holder shaft 491. The electrode wires are provided electric current from electrical lines run through processing pivot shaft 429 and/or 430.
The electrical line run through pivot shaft 430/429 will by nature be stationary with respect to processing head housing 470. However, since the workpiece holder rotor is intended to be capable of rotation during the electroplating process, the wires passing into workpiece support shaft 491 through electrode wire holes 525 may rotate with respect to processing head housing 470. Since the rotating electrode wires within workpiece shaft 491 and the stationary electrical supply lines run through pivot shaft 430/429 must be in electrical communication, the rotational/stationary problem must be overcome. In the preferred embodiment, this is accomplished by use of electrical slip ring 494.
Electrical slip ring 494, shown in
Processing Head Finger Actuators
Workpiece holder 478, described more fully below, advantageously includes fingers for holding the workpiece W in the workpiece holder, as shown in
Pneumatic piston 502 is attached to actuator plate 509 by actuator plate connect screw 510. Wave springs 529 provide flexibility to the connecting at screws 510. Actuator plate 509 is preferably an annular plate concentric with the spin motor 580 and disposed about the bottom motor housing 482, and is symmetrical about spin axis 479. Actuator plate 509 is secured against pneumatic piston 502 by bushing 512 which is disposed in pneumatic piston recess 511 about pneumatic piston 502. Bushing 512 acts as a support for wave springs 529 to allow a slight tilting of the actuator plate 509. Such an arrangement is beneficial for providing equal action against the finger actuator contracts 513 about the entire actuator plate or ring 509.
When pneumatic fluid is provided to the space above the pneumatic piston 502, the pneumatic piston 502 travels in a downward direction compressing actuator spring 505. As pneumatic piston 502 travels downward, actuator plate 509 is likewise pushed downward by flexible bushing 512. Actuator plate 509 will contact finger actuator contacts 513 causing the fingers to operate as more fully described below.
Actuator seals 506 are provided to prevent pneumatic gas from bypassing the top of the pneumatic piston 502 and entering the area occupied by actuator spring 505.
Processing Head Workpiece Holder
Workpiece holder 478 is used to hold the workpiece W, which is typically a semiconductor wafer, in position during the semiconductor manufacturing process.
Turning now to
Finger actuator lever 514 is advantageously biased in a horizontal position by finger spring 520 which acts on finger actuator tab 522 which in turn is connected to finger actuator lever 514. Finger spring 520 is preferably a torsion spring secured to the workpiece holder rotor 484.
Finger stem 515 is also preferably provided with finger collar or nut 517 which holds the finger stem 515 against shoulder 518. Finger collar 517 threads or otherwise securely fits over the lower end of finger actuator lever 514. Below the finger collar 517, finger stem 515 extends for a short distance and terminates in fingertip 414. Fingertip 414 contains a slight groove or notch which is beneficially shaped to receive the edge of the workpiece W.
In actuation, finger actuator plate 509 is pushed downward by finger actuator mechanism 500. Finger actuator plate 509 continues its downward travel contacting finger actuator contacts 513. As actuator plate 509 continues its downward travel, finger actuator contacts are pushed in a downward direction. As a result of the downward direction, the finger actuator levers 514 are caused to pivot.
In the preferred embodiment, a plurality of fingers are used to hold the workpiece. In one example, six fingers were used. Once the actuator plate 509 has traveled its full extent, the finger stems 515 will be tilted away from the spin axis 479. The circumference described by the fingertips in this spread-apart position should be greater than the circumference of the workpiece W. Once a workpiece W has been positioned proximate to the fingertips, the pneumatic pressure is relieved on the finger actuator and the actuator spring 505 causes the pneumatic piston 502 to return to the top of the cavity 501. In so doing, the actuator plate 509 is retracted and the finger actuator levers are returned to their initial position by virtue of finger springs 520.
Semiconductor Workpiece Holder—Electroplating Embodiment
Workpiece holder 810 is used for processing a semiconductor workpiece such as a semiconductor wafer shown in phantom at W. One preferred type of processing undertaken with workpiece holder 810 is a workpiece electroplating process in which a semiconductor workpiece is held by workpiece holder 810 and an electrical potential is applied to the workpiece to enable plating material to be plated thereon. Such can be, and preferably is accomplished utilizing a processing enclosure or chamber which includes a bottom half or bowl 811 shown in phantom lines in
Processing Head and Processing Head Operator
Turning now to
The workpiece can be removed from or fixed to workpiece holder 810 automatically by means of a robotically controlled arm. Alternatively, the workpiece can be manually removed from or fixed to workpiece holder 810. Additionally, more than one workpiece holder can be provided to support processing of multiple semiconductor workpieces. Other means of removing and fixing a semiconductor workpiece are possible.
Referring now to
Finger assembly 824 includes a finger assembly frame 832. Preferably, finger assembly frame 832 is provided in the form of a sealed contact sleeve which includes an angled slot 832 a, only a portion of which is shown in
Finger assembly frame 832 includes a finger assembly frame outer flange 834 which, as shown in
Finger Assembly Drive System
Finger Assembly Electrical System
Finger 848 is advantageously fixed or secured to or within collet 840 by a nut 850 which threadably engages a distal end portion of collet 840 as shown best in
Finger assembly 824 may also optionally include a distal tip or finger tip 854. Tip 854 may also have a purge gas passage formed therethrough. Finger tip 854 advantageously engages against a semiconductor workpiece (see
Finger Assembly Drive System Interface
A finger assembly drive system interface is operatively coupled with the finger assembly drive system to effectuate movement of the finger assembly between the engaged and disengaged positions. A preferred finger assembly drive system interface is described with reference to
The finger assembly drive system interface includes pneumatic actuator 825 (
Pneumatic actuator linkage 825 also includes a secondary linkage 865. Secondary linkage 865 is pneumatic as well and includes a link arm 867. Link arm 867 is connected or joined to an actuator torque ring 869. Preferably, torque ring 869 is concentric with rotor 820 (
Preferably finger actuator engagement bits 862, under the influence of pneumatic linkage 825, moves the finger assembly, and more specifically collet 840 and finger 848 along a first axial movement path along axis 864. The finger actuator engagement bits 862, then under as the influence of pneumatic operator 871 are turned about the axes of each bit like a screwdriver. This moves collet 840 and finger 848 in a second angular movement. Such second movement turns the fingers sufficiently to produce the angular displacement shown in
The engagement bits 862 can be provided with a purge gas passage therethrough. Gas is supplied via tube 893 and is passed through the finger assemblies.
Engaged and Disengaged Positions
As shown in
Finger Assembly Seal
The finger assembly preferably includes a finger assembly seal 868 which is effectuated between finger 848 and a desired workpiece when the finger assembly is moved into the engaged position. Preferably, adjacent finger tip 854. Seal 868 is mounted adjacent electrode contact 858 and effectively seals the electrode contact therewithin when finger assembly 824 is moved to engage a workpiece. The seal can be made of a suitable flexible, preferably elastomeric material, such as VITON.
More specifically, and referring to
Methods and Operation
In accordance with a preferred processing aspect of the present invention, and in connection with the above-described semiconductor workpiece holder, a sheathed electrode, such as electrode 856, is positioned against a semiconductor workpiece surface in a manner which permits the electrode to impart a voltage bias and current flow to the workpiece to effectuate preferred electroplating processing of the workpiece. Such positioning not only allows a desired electrical bias to be imparted to a held workpiece, but also allows the workpiece itself to be mechanically held or fixed relative to the workpiece holder. That is, finger assembly 824 provides an electrical/mechanical connection between a workpiece and the workpiece holder as is discussed in more detail below.
Sheathed electrode 856 includes a sheathed electrode tip or electrode contact 858 which engages the workpiece surface. A seal is thus formed about the periphery of the electrode tip or contact 858 so that a desired electrical bias may be imparted to the workpiece to enable plating material to be plated thereon. According to a preferred aspect of the processing method, the sheathed electrode is moved in a first direction, preferably longitudinally along a movement axis, away from a disengaged position in which the workpiece surface is not engaged by the sheathed electrode tip or contact 858. Subsequently, the sheathed electrode is rotated about the same movement axis and toward an engaged position in which the electrode tip may engage, so as to fix, and thereafter bias the workpiece surface. Such preferred movement is effectuated by pneumatic linkage 825 and pneumatic operator 871 as described above.
According to a preferred aspect of the invention, the seal which is effectuated between the sheath tip and the workpiece is formed by utilizing a yieldable, deformable sheath tip or terminal end 868 which includes a sheath tip rim portion 870. The sheath tip rim portion 870 advantageously splays outwardly upon contacting the workpiece surface to form a continuous seal about the periphery of the electrode tip as shown in
In addition to providing the preferred electrical contact between the workpiece and the electrode tip, the finger assembly also forms a mechanical contact or connection between the assembly and the workpiece which effectively fixes the workpiece relative to the workpiece holder. Such is advantageous because one aspect of the preferred processing method includes rotating the workpiece about rotor axis 822 while the workpiece is exposed to the preferred plating material. Such not only ensures that the electrical connection and hence the electrical bias relative to the workpiece is maintained during processing, but that the mechanical fixation of the workpiece on the workpiece holder is maintained as well.
The above described pneumatically effectuated movement of the preferred finger assemblies between the engaged and disengaged positions is but one manner of effectuating such movement. Other manners of effectuating such movement are possible.
Methods Re Presenting Workpiece
The invention also includes novel methods for presenting a workpiece to a semiconductor process. In such methods, a workpiece is first secured to a workpiece holder. The methods work equally well for workpiece holders known in the art and for the novel workpiece holders disclosed herein.
In the next step in the sequence, the workpiece holder is rotated about a horizontal axis from an initial or first position where the workpiece holder was provided with the workpiece to a second position. The second position will be at an angle to the horizontal. The angle of the workpiece holder to the horizontal is defined by the angle between the plane of the workpiece and the horizontal. In the method, the workpiece holder is advantageously suspended about a second horizontal axis which is parallel to the first horizontal axis of the workpiece holder. At this point in the method, the angle between the first and second horizontal axes and a horizontal plane corresponds to the angle between the workpiece holder and the horizontal. The workpiece holder is then pivoted about the second horizontal axis to move the workpiece and the workpiece holder from its initial location to a final location in a horizontal plane. Advantageously, when the workpiece holder is pivoted about the second horizontal axis, the first horizontal axis also pivots about the second horizontal axis.
Preferably, during the step of rotating the workpiece holder about the first horizontal axis, the angle of the workpiece holder with respect to some known point, which is fixed with respect to the workpiece holder during the rotation process, is continually monitored. Monitoring allows for precise positioning of the workpiece holder with respect to the horizontal surface.
Likewise, during pivoting of the workpiece holder about the second horizontal axis, it is preferable that the angle defined by the line connecting the first and second horizontal axes and the horizontal plane be continually monitored. In this manner, the absolute position of the workpiece holder (and hence the workpiece itself) will be known with respect to the horizontal plane. This is important since the horizontal plane typically will contain the process to which the workpiece will be exposed.
It should be noted that in the above and following description, while the workpiece is described as being presented to a horizontal plane, it is possible that the workpiece may also be presented to a vertical plane or a plane at any angle between the vertical and the horizontal. Typically, the processing plane will be a horizontal plane due to the desire to avoid gravitational effects on process fluids to which the workpiece is exposed. In one embodiment after the workpiece has been presented to the processing plane, the workpiece holder is rotated about a spin axis to cause the workpiece to spin in the horizontal plane. Although not required in all semiconductor manufacturing processes, this is a common step which may be added in the appropriate circumstance.
The next advantageous step in the method consists of pivoting the workpiece holder about the second horizontal axis back along the path that the workpiece holder was initially pivoted along when presenting the workpiece to the horizontal process plane. There is no requirement that the workpiece holder be pivoted back to the same position whence it began, although doing so may have certain advantages as more fully described below.
The method advantageously further consists of the step of rotating the workpiece holder about the first horizontal axis to return the workpiece to the position when it was initially presented to and engaged by the workpiece holder. It is advantageous to rotate the workpiece holder about the first axis in a direction opposite from the initial rotation of the workpiece holder.
The advantage of having the workpiece holder terminate at an end position which corresponds to the initial position when the workpiece was loaded into the workpiece holder is efficiency. That is, additional machine movements are not required to position the workpiece holder to receive a new workpiece.
The method more preferably includes the step of rotating the workpiece holder about the first horizontal axis at at least two support points along the first horizontal axis. This beneficially provides support and stability to the workpiece holder during the rotation process and subsequent movement of the apparatus.
The method also more preferably includes the step of pivoting the workpiece holder along with the first horizontal axis about the second horizontal axis at at least two support points along the second horizontal axis. This beneficially provides additional support for the workpiece holder while allowing the workpiece holder to be moved in a vertical or “Z-axis” direction.
Importantly, the only motion described in the above method is rotational motion about several axes. In the method described, there is no translational motion of the workpiece holder in a X-, Y-, or Z-axis without corresponding movement in another axis as a result of rotating through an arc.
Electroplating Processing Station
The workpiece process tool may comprise several different modules for performing a variety of manufacturing process steps on the workpiece or semiconductor wafer. The workpiece processing tool may advantageously contain electroplating module 20, alternately known more generally as a workpiece processing station.
The plating module 20 of
Workpiece support 601 is shown in a “open” or “receive wafer” position whereby a robotic arm or other means will provide a workpiece to the workpiece support. The workpiece support will positively engage the workpiece (described more fully below) by fingers 409 (or more precisely, by finger tips of finger assemblies, which are also described more fully below). The processing head 406 will then rotate about the operator arm 407 to place the workpiece in an essentially downward facing position. Operator arm 407 will then pivot about operator base 405 to place the workpiece in the processing bowl as shown at 602 of
Although the invention is described for an electroplating process, it is to be noted that the general arrangements and configurations of the workpiece processing stations and their combination into a multi-workpiece processing station unit may be applied to a variety of processes used in manufacturing.
The details of the bowl assemblies and their arrangement and configuration with the other components of the invention described herein are described more fully below.
The process fluid reservoir 604 is mounted within the processing module 20 by attaching it to the module frame or chassis 606. Turning to
Turning briefly to
The process module may also be provided with a heat exchanger 613. Turning to
The invention further advantageously includes a cup assembly 620 which is disposed within process bowl 616. Cup assembly 620 includes a fluid cup 621 having a cup side 622 and a cup bottom 623. As with the process bowl, the fluid cup 621 is preferably circular in horizontal cross section and cylindrical in shape, although a tapered cup may be used with a tapered process bowl.
Process fluid is provided to the process bowl 616 through fluid inlet line 625. Fluid inlet line rises through bowl bottom opening 627 and through cup fluid inlet opening 624 and terminates at inlet line end point 631. Fluid outlet openings 628 are disposed within the fluid inlet line 625 in the region between the cup fluid inlet opening 624 and fluid line end point 631. In this way, fluid may flow from the fluid inlet line 625 into the cup 621 by way of the inlet plenum 629.
The cup assembly 620 preferably includes a cup filter 630 which is disposed above the fluid inlet openings and securely fits between the inner cup wall 622 and the fluid inlet line 625 so that fluid must pass through the filter before entering the upper portion of cup 621.
In an electroplating process, the cup assembly 620 is advantageously provided with a metallic anode 634. Anode 634 is secured within the cup assembly by attaching it to the end point 631 of the fluid inlet line. Anode 634 is thus disposed above the cup filter 630 as well as above fluid inlet opening 628. Anode 634 is preferably circular in shape and of a smaller diameter than the inside diameter of cup 621. Anode 634 is secured to the end point 631 of fluid inlet line 625 so as to center the anode 634 within cup 621 creating an annular gap or space 635 between the inner cup wall 622 and the edge of anode 634. Anode 634 should be so placed such as to cause the anode annular opening 635 to be of a constant width throughout its circumference.
The outer cup wall 636 is advantageously of a smaller diameter than the inside diameter of bowl 616. Cup assembly 620 is preferably positioned within bowl 616 such that a first annular space or process fluid overflow space 632 is formed between bowl side 617 and cup outer wall 636. The cup assembly is more preferably positioned such that the annular fluid overflow space 632 is of a constant width throughout its circumference.
Cup assembly 620 is further advantageously positioned within bowl 616 such that cup upper edge 633 is below bowl upper edge 637. Cup 621 is preferably height-adjustable with respect to bowl upper edge 637, as more fully described below.
Bowl bottom 619 is preferably configured so as to have a large open area allowing the free transfer of fluid therethrough. In the preferred embodiment, this is achieved by the structure shown in
Thus, operation, process fluid is provided through process fluid inlet line 625 and discharges through fluid outlet openings 628 within the lower part of the cup assembly 620. By virtue of cup filter 620, fluid entering the fluid inlet plenum 629 is distributed across the plenum and then flows upward through filter 630 to the bottom of anode 634.
From the top side of filter 630, the process fluid continues to flow in an upward direction by virtue of continuing feed of process fluid through process inlet line 625. The process fluid flows around the annular gap 635 between the anode 634 and the inner cup wall 622. As the process fluid continues to well up within cup 621, it will eventually reach upper cup edge 633 and will overflow into the overflow annular gap 632 between the outer cup wall 636 and the inner wall of bowl 616.
The overflowing fluid will flow from the overflow gap 632 downward through the gap and back into reservoir 604 where it will be collected for reuse, recycling, or disposal. In this manner, no process fluid return line is required and no elaborate fluid collection system is necessary to collect surplus fluid from the process.
As a further advantage, the location of the cup filter 630 and anode 634 within the cup 621 provides an even distribution of fluid inlet into the cup. The even distribution beneficially assists in providing a quiescent fluid surface at the top of cup 621. In like manner, maintaining a constant distance between the outer wall of cup 636 and the inner wall of bowl 616 in providing the overflow gap 632 will assist in providing an even flow of fluid out of cup 621 and into the reservoir 604. This further beneficially assists in providing the desired quiescence state of the process fluid at the top of cup 621.
The material selection for cup filter 620 will be dictated by the process and other operating needs. Typically, the filter will have the capability of filtering particles as small as 0.1 microns. Likewise, the choice of materials for anode 634 will be dictated by the desired metal to be electroplated onto the workpiece.
While the above bowl assembly has been described particularly for an electroplating process, it can be seen that for a process where a flow of fluid is required but no anode is required removing the anode 634 from the cup assembly 603 will provide a quiescent pool of liquid for the process. In such an arrangement, the end point 631 of the fluid inlet line 625 would be capped or plugged by a cap or plug rather than by the anode 634.
To assist in ensuring that process fluid overflows into the annular gap 632 evenly, it is necessary to ensure that the cup upper edge 633 is level such that fluid does not flow off of one side of cup 621 faster than on another side. To accomplish this objective, levelers are preferably provided with the process bowl assembly 603.
Turning now to
Since process bowl assembly 603 is free to move with respect to fluid reservoir 604, when process bowl assembly 603 is fit closely within fluid reservoir 604 as shown in
Cup assembly 620 is preferably provided with cup height adjuster 641. The cup height adjuster shown and described herein consists of a cup height adjustment jack 643 which is positioned about an externally portion of inlet line 625. Cup 621 is secured to cup height adjustment jack 643 with cup lock nut 642. Cup lock nut 642 is used to secure cup 621 in its height position following adjustment. The upper end of cup height adjustment jack 641 is provided with adjustment tool access holes 667 to allow for adjusting of the height of the cup from the top of the bowl rather than the underside. The cup height adjuster 641 may additionally be provided with a fluid seal such as an o-ring (not shown) disposed within the annular space formed between the adjsutment jack 643 and the cup bottom 623.
The process bowl assembly 603 is more preferably provided with an additional height adjuster for the anode 634. Since it is desirable to be able to adjust the distance between the anode 634 and the workpiece based upon the particular electroplating process being used, anode height adjuster 646 is beneficially provided. Anode height adjuster 646 is formed by mounting the anode 634 on the threaded anode post 664. A threaded anode adjustment sleeve 663 is used to connect the threaded upper end of inlet line 625. Anode adjustment sleeve 663 is provided with sleeve openings 668 to allow fluid to pass from fluid outlet openings 628 into the inlet plenum 629. The space between the bottom of anode post 664 and the upper end of fluid inlet line 625, and bounded by the anode adjustment sleeve 663, defines a fluid outlet chamber 662. Fluid outlet chamber is of variable volume as the anode post 664 moves upward and downward with height adjustment of the anode 634.
On the bowl leveler 640 and the height adjusters 641 and 646 described above, it is additionally desirable to provide them with locking mechanisms so that once the desired positioning of the device (i.e., the bowl, the cup, or the anode) is achieved, the position may be maintained by securing the adjusters so that they do not move out of adjustment as a result of vibration or other physical events.
Allowing independent height adjustment of the cup and anode each with respect to the bowl provides a large degree of flexability in adjusting the process bowl assembly 603 to accomodate a wide selection of processes.
Fluid Transfer Equipment
To provide process fluid to the process bowl assembly in the electroplating module of the present invention, the module is advantageously provided with fluid transfer equipment. The fluid transfer equipment is provided to draw process fluid from a reservoir, supply it to the process bowl assemblies, and return it to a common collection point.
Turning now to
In alternate embodiments of the present invention, a submersible pump may be deployed. However, the immersible pump has the advantage that it may be easily removed for servicing and the like. In yet another embodiment, individual pumps for each of the process bowl assemblies may be deployed or, process bowls assemblies may share a set of common pumps. Each such pump would have a process fluid inlet suction and a process fluid discharge.
Returning to the preferred embodiment of
From the pump discharge filter 607, the process fluid exits through filter outlet 651 and into supply manifold 652. The supply manifold supplies all of the process bowl assemblies 603 with process fluid. Branching off from the supply manifold 652 are the individual fluid inlet lines 625. The fluid inlet lines 625 are preferably provided with flow control devices which are more fully described below.
At the down stream end of the supply manifold 652 after the final processing bowl assembly 661, the manifold is routed to fluid return line 654. Although the supply manifold could be terminated at an open ended point at optional end point 655, in the preferred embodiment, the supply manifold 652 is additionally provided with a back pressure regulator 656, which is described more fully below. Since it is advantageous to have the back pressure regulator outside of the fluid reservoir for ease of access, the fluid return line 654 is provided when the back pressure regulator 656 is employed.
In the preferred embodiment, the work station processing module of the present invention further includes devices for controlling the flow and distribution of the process fluid to the process bowl assemblies.
With reference to
The processing modules 603 are also preferrably provided with flow restrictors 658 which are disposed in fluid inlet lines 625 after the flow sensor 657 but before the fluid outlet opening 628 within cup 621 (shown in
More preferably, the semiconductor processing module is provided with back pressure regulator 656. As pump discharge filter 607 becomes restricted due to captured filtrate, the pressure within supply manifold 652 will drop, reducing flow of process fluid to the fluid cups 621. Back pressure regulator 656 is used to maintain a preselected pressure in the supply manifold 652 to ensure that sufficient pressure is available to provide the required flow of process fluid to the fluid cups. Back pressure regulator 656 further comprises an internal pressure sensor and preferably includes a signal generator for generating a control signal to open or close the back pressure regulator to increase or decrease the pressure in the supply manifold. The back pressure regulator may be controlled by an external controller such as a micro processor or it may have a local set point and be controlled by an internal local control mechanism.
In an alternate embodiment, where a dedicated process pump is used for each process bowl assembly, a back pressure regulator would typically not be required.
The present invention also includes a novel method for processing a semiconductor workpiece during manufacturing.
In the preferred embodiments of the method, a semiconductor workpiece or wafer is presented to the semiconductor manufacturing process. This may be accomplished by use of the workpiece support 401 shown in
The workpiece W is preferably presented to the process in a precisely located position so that all surfaces of the workpiece are exposed to the solution. In an electroplating process, it is advantageous to expose only the downward facing or working surface of the wafer to the electrolytic solution and not the backside of the wafer. This requires accurate positioning of the wafer with respect to the fluid surface. In an electroplating process, the method also requires the step of accurately positioning the workpiece with respect to the anode 634 so that the anode and workpiece are separated by an equal distance at all points.
Once the workpiece has been positioned as the process may specifically require, the next step in the method is performing the actual processing step itself. For example, in an electroplating application, the processing step would include applying an electric current to the workpiece so as to generate the current through the electrolytic solution thereby plating out a layer of a desired metallic substance on the wafer. Typically a current will be applied to the anode as well, with a negative current being applied to the workpiece. The processing step is applied for the length of time which is dictated by the process itself.
The process further includes the step of continuing a flow of the process fluid such that the process fluid overflows the processing chamber and falls under gravitational forces into a process fluid reservoir. Preferrably the process fluid reservoir is the same reservoir which provides the process fluid or solution to the process.
As an additional step in the method of processing the semiconductor wafer in the electroplating process, the method includes the further step of spinning or rotating the workpiece about a vertical axis while it is exposed to the electrolytic solution. The rate of rotation varies between about 5 and 30 rpm and is more preferably approximately 10 rpm. The rotation step provides the beneficial result of additional assurance of even distribution of the electrolytic solution across the face of the workpiece during the electroplating process.
After the processing has been performed on the semiconductor wafer, the method advantageously includes the step of removing the workpiece from the process and returning it to a position where it may be removed for further processing or removal from the semiconductor workpiece process tool.
The method preferably includes the step of performing the above-described steps at a series of process bowls having a common fluid reservoir such that the overflowing fluid gravity drains into a common fluid reservoir.
In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.