|Publication number||USRE43023 E1|
|Application number||US 12/724,026|
|Publication date||Dec 13, 2011|
|Filing date||Mar 15, 2010|
|Priority date||Apr 17, 2000|
|Also published as||US6641350, US20010038783|
|Publication number||12724026, 724026, US RE43023 E1, US RE43023E1, US-E1-RE43023, USRE43023 E1, USRE43023E1|
|Inventors||Takanobu Nakashima, Tatsuhisa Matsunaga, Hidehiro Yanagawa|
|Original Assignee||Hitachi Kokusai Electric Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (30), Non-Patent Citations (4), Referenced by (5), Classifications (11), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present application claims priority from Japanese Patent Application No. 2000-114818, filed Apr. 17, 2000, and is a reissue application of U.S. Pat. No. 6,641,350, issued Nov. 4, 2003, the contents of which are incorporated herein by reference. More than one reissue application has been filed for the reissue of U.S. Pat. No. 6,641,350. The reissue applications are application Ser. No. 12/724,026 (the present application), and application Ser. Nos. 12/724,613 and 12/724,625, both filed Mar. 16, 2010, and both of which are continuation reissue applications of the present application, and both of which are now abandoned.
The present invention relates to a semiconductor processing equipment; and, more particularly, to a device for moving doors of substrate carriers, e.g., for use in a semiconductor processing equipment such as a batch-type vertical apparatus for performing a diffusion or a CVD (chemical vapor deposition) process to form diffusion, dielectric or metallic layers on semiconductor wafers.
In a semiconductor processing equipment such as a batch-type vertical apparatus for performing a diffusion or a CVD process, semiconductor wafers are loaded into and unloaded from the apparatus while being kept in cassettes. Two kinds of carriers have been conventionally used. One is a box-shaped cassette having a pair of openings on two opposite sides and the other is a box-shaped FOUP (front opening unified pod; hereinafter, pod) having an opening on one side thereof with a pod door removably mounted thereon.
In the semiconductor processing equipment using the pod as the carrier, the wafers can be kept protected from contaminations of ambient atmosphere while being transferred since the pod containing the wafers is airtightly closed. Accordingly, the degree of cleanliness required for a clean room of the semiconductor processing equipment may be lowered, which in turn reduces cost for the maintenance of the clean room. For such reasons, the pod is gaining popularity as the carrier in the semiconductor processing equipment recently.
The semiconductor processing equipment using the pod as the wafer carrier is provided with a pod door opener for remaining and restoring the pod door. One example of such conventional pod door opener is disclosed in U.S. Pat. No. 5,772,386, wherein the pod door opener is disposed on a wafer loading port and equipped with a closure capable of frictionally engaging with a door of the pod located on the wafer loading port. The pod can be uncovered by lowering down the closure while the closure engages with the door.
However, since the conventional semiconductor processing equipment is provided with only a single wafer loading port, the lead time required in preparing wafers for an actual process increases due to replacement of a pod on the wafer loading port with another, which in turn lengthens the overall processing time of the semiconductor manufacturing process, thereby reducing the throughput thereof.
Another equipment having a multi-stage pod door system is disclosed in U.S. Pat. No. 6,042,324. Since, however, the pod doors of the equipment are simultaneously opened as a single unit by a vertical actuator, the lead time may not be reduced and the height of the equipment increases.
It is, therefore, a primary object of the present invention to provide a semiconductor processing equipment capable of increasing the throughput thereof.
In accordance with one aspect of the present invention, there is provided a semiconductor processing equipment comprising:
In accordance with another aspect of the present invention, there is provided a method for processing wafers for use in a method for processing substrates for use in a semiconductor processing equipment having at least two loading ports, a plurality of carriers each of which contains a portion of the substrates, a carrier shelf for storing the carriers, a reaction chamber and a boat for loading and unloading the substrates into and out of the reaction chamber, the method comprising the step of transferring the substrates between the carriers and the boat, wherein the transferring step includes the steps of:
The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which:
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings.
Formed on a front wall of the housing 2 is a pod load/unload opening (not shown) through which pods 10 can be loaded into or unloaded from the housing 2. The pod load/unload opening can be open and closed by a shutter (not shown). In front of the pod load/unload opening, a pod stage 11 is provided for receiving multiple, e.g., two, pods at a time.
At the upper central portion of the semiconductor processing equipment 1, a rotatable pod shelf 12 is arranged. The pod shelf 12 is capable of holding, e.g., eight pods 10. The numbers of pods that the pod shelf 12 can support is not limited to eight but may be increased, e.g., up to sixteen. The pod shelf 12 has two vertically disposed swastika-shaped pod supporting plates, each being capable of holding, e.g., 4 pods simultaneously. The pod shelf 12 is uni-directionally rotatable in a horizontal plane on a pitch-by-pitch basis by a rotary actuator (not shown), e.g., a stepping motor.
Below the pod shelf 12, there is provided a two pod openers 20 each of which includes a wafer loading port 13, bulkhead 21 and a closure 40. The wafer loading ports 13 through which the wafers are carried into or out of the pod 10 are vertically stacked.
Inside the housing 2, a pod handler 14 is installed between the pod stage 11 and the pod shelf 12. The pod handler 14 is adapted to transfer pods between the pod shelf 12 and the wafer loading ports 13 and between the pod shelf 12 and the pod stage 11. Pod transfer may also be conducted between the pod stage 11 and the wafer loading ports 13, if necessary. Moreover, a wafer carry assembly 15 is provided between the boat 8 and the wafer loading ports 13 to transfer wafers 9 therebetween.
Details of the pod opener 20 will now be described with reference to
As shown in
As shown in
The loading platform 27 also has a substantially square frame shape with some cutout portion at the distal end thereof away from the bulkhead 21. On the upper surface of the loading platform 27, vertically oriented alignment pins 28 provided at locations corresponding to, e.g., three corner points of an equilateral triangle. These pins are adapted to match with corresponding holes (not shown) formed at a bottom surface of the pod 10.
As shown in
As shown in
Mounted on the top surface of the back/forth slider 34 is a bracket 39. A square-shaped closure 40 larger than the opening 22 is vertically fixed to the bracket 39. The square-shaped closure 40 is movable in the to-and-fro direction by the movement of the back/forth slider 34 and in the left-right direction by the movement of the angle-shaped slider 31. The front surface of the closure 40 facing toward the wafer loading ports 13 has a peripheral region and a central region thicker than the peripheral region. That is, the distance from the front surface at the central region (hereinafter, referred to as central front surface) to the rear surface of the closure 40 is greater than that for the front surface at the peripheral region (hereinafter, referred to as peripheral surface) of the closure 40. The size of the central region of the front surface of the closure 40 is slightly smaller than the opening 22, so that the central region can get into the opening 22.
By such configuration, a peripheral front surface of the closure 40 can firmly abuts with the periphery of the opening 22 by moving forward the back/forth slider 34 against the bulkhead 21 and, thereby closing the opening 22 can be closed.
Further, as shown in
As shown in
As shown in
In operation, the pods 10 are loaded onto the pod stage 11 through the pod load/unload opening and then transferred by the pod handler 14 to predetermined positions on the pod shelf 12 for temporary storage as shown in
The two pod openers 20 are arranged to close the openings 22 such that the packing member 55 seals against the rear side wall of the bulkhead 21. One pod 10 is transferred from the pod shelf 12 to, e.g., the upper wafer loading port 13 by the pod handler 14 and disposed on the loading platform 27. The three alignment pins 28 on the loading platform 27 engage with the corresponding three holes (not shown) formed under the pod 10 to thereby complete the alignment of the pod 10 on the loading platform 27.
The pod 10 provided on the loading platform 27 is moved toward the bulkhead 21 by the extension of the air cylinder 26 in such a manner that the respective packing members 54 and 56 are airtightly in contact with the pod door 10a and the pod frame therearound as shown in
After completing the pod transferring process “A”, a negative pressure is applied through the air exhaust/supply pipes 47 inside the suction elements 46 so that the suction elements 46 hold the door 10a by vacuum suction. Thereafter, the keys 41 are rotated by the air cylinder 45 so that the coupling members 41a unlock the door 10a.
Next, the back/forth slider 34 is moved away from the bulkhead 21 by the rotary actuator 37 and then the angle-shaped slider 31 is moved away from the opening 22 by the air cylinder 32 so that the closure 40 holding the pod door 10a by the suction elements 46 is moved to a retreated position. By such movement of the closure 40, the door 10a is separated from the pod 10 and the pod is opened as shown in
Thereafter, as shown in
Next, the wafers in the pod 10 on the wafer loading port 13 are transferred to the wafer boat 8 by the wafer transfer assembly 15. The wafer transferring process described above is generally represented as a process “D” at after the first stage in
While the wafer transferring process “D” is performed at after the first stage, e.g., the upper wafer loading port 13, the pod transferring process “A”, the pod door opening process “B” and the mapping process “C” are sequentially carried out at the second stage, e.g., the lower wafer loading port 13. the The second wafer loading port 13 waits (process E “F”) until the wafer transferring process “D” at the first wafer loading port 13 is completed.
Accordingly, upon the completion of the wafer transferring process “D” of the first wafer loading port 13 at, for which the second stage is waiting (process “F”), the wafer transferring process “D” can be started at the second wafer loading port 13 as shown in
During the third stage shown in
The pod door closing process is carried out as follows. The closure 40 holding the pod door 10a is removed from the retreated position toward the opening 22 by the air cylinder 32 and then toward the empty pod 10 by the rotary actuator 37 to close the pod 10 by the pod door 10a thereafter, the keys 41 are rotated by the air cylinder 45 to actuate the locking mechanism of the pod door 10a. After locking, the negative pressure inside the suction element 46 is removed by supplying a positive pressure through the pipe 47 and the closure 40. The closure 40 remains in that position until the pod door opening process “B” is resumed.
The pod changing process “A” is carried out as follows. After the pod door 10a is restored on the empty pod 10 by the pod door closing process “E”, the loading platform 27 of the first wafer loading port holding the empty pod is moved away from the bulkhead 21 by the air cylinder 26. The empty pod 10 is then stored back to the pod shelf 12 and a new pod holding wafer therein is transferred to the first wafer loading port. Thereafter, the newly supplied pod is provided to the closure 40 in an identical manner as in the pod transferring process “A”. The remaining process “B”, “C” and “F” are identical to those of the second stage.
The wafer loading processes are repeated until the described number of wafers are loaded from the pods 10 to the wafer boat 8. After transferring the described number of wafers, the last two empty pods may be removed to the pod shelf 12 or stayed on the wafer loading ports 13. Alternatively, only one empty port 13 may remain at the one wafer loading port 13. The number of wafers which the wafer boat 8 can hold for one batch process is, e.g., 100 to 150, which is several times greater than that of wafers which one pod can contain therein, e.g., 25.
After the predetermined number of unprocessed wafers are loaded on the wafer boat 8, the boat elevator 7 lifts the wafer boat 8 into the process tube 4. When the wafer boat 8 is introduced into the process tube 4, a lower end opening of the process tube 4 is hermetically sealed by the boat receptacle 8a.
Next, the process tube 4 is evacuated through the exhaust pipe 6 to reduce the pressure therein down to a predetermined vacuum level. Thereafter, a desired wafer process, e.g., a diffusion or a CVD process, is carried out on the loaded wafers by controlling temperatures at desired levels by using the heater unit 3 while supplying predetermined process gases into the process tube 4 through the gas supply line 5.
After a predetermined processing time has elapsed, the wafer boat 8 holding processed wafers is discharged from the process tube 4 and returned to its initial position. During the period in which the wafer boat 8 is loaded into and unloaded from the process tube 4 and the wafers are processed in the process tube 4, either one or both of the pods 10 may be prepared at the corresponding wafer loading ports 13 in order to receive the processed wafers.
Thereafter, the wafer transfer assembly 15 transfers a portion of the processed wafers held in the wafer boat 8 to one empty pod 10 disposed on, e.g., the first wafer loading port 13 (upper loading port) with the door 10a opened. This process corresponds to the wafer transferring process “D” at the second stage shown in
While the wafer loading process “D” is carried out at the second wafer loading port, the pod door closing process “E”, the pod changing process “A”, the pod door opening process “B” and the waiting process “F” are carried out at the first wafer loading port as in the third stage of
The process “E”, “A”, “B” and “F” are identical to those described with respect to the wafer loading process from the pods 10 to the wafer boat 8, excepting that the pod changing process “A” represents the process transferring a pod containing the processed wafers to the pod shelf 12 from a wafer loading port and moving an empty pod from the pod shelf 12 to the wafer loading port 13.
In case all the empty pods have been transferred from the wafer loading ports 13 to the pod shelf 12 after loading all the wafers onto the boat 8, the processed wafer unloading process can be accomplished as follows. First, one empty pod is transferred from the pod shelf 12 to one of the wafer loading ports and the pod door 10a thereof is opened. These correspond to the process “A” and “B” of the first stage in
Thereafter at the second stage, the wafer transferring process “D” is carried out at the first wafer loading port 12, while the process “A”, “B” and “F” are sequentially performed at the second wafer loading port. Then, the process at the third stage can be carried out as described above.
The processes are repeated until transferring all the processed wafers from the wafer boat 8 to the empty pods, which in turn are returned to the pod shelf 12.
As described above, since the wafer transfer assembly 15 can transfer the processed wafers from the wafer boat 8 to the pods 10 continuously without having to wait for the replacement of the pods 10 on the wafer loading ports 13, the throughput of semiconductor processing equipment 1 can be substantially increased.
The pods 10 containing the processed wafers are temporarily stored in the pod shelf 12 and then transferred to the pod stage 11 by the pod handler 14. Next, the pods on the pod stage 11 are transferred through the pod load/unload opening (not shown) to another equipment for a subsequent process and new pods containing unprocessed wafers are charged on the pod stage 11.
The processes of transferring pods between the pod shelf 12 and the pod stage 11 and charging and discharging pods into and from the semiconductor processing equipment 1 can be carried out while wafers are being processed in the process tube 4 and transferred between the wafer boat 8 and the pods 10 on the wafer loading ports 13. As a result, the total process time of the semiconductor processing equipment 1 can be reduced.
The wafer transferring sequence in accordance with the second embodiment of the present invention will be described with reference to
Immediately thereafter at the second stage, wafer transferring from the first pod to the wafer boat 8 (process “D”) starts and, at the same time, a second pod containing the unprocessed wafers are transferred to a second wafer loading port (process “A”) and waits until the wafer transferring process “D” at the first wafer loading port is completed (process “F”).
At the third stage, the door of the second pod is opened (process “B”) and the wafers therein are transferred to the boat 8 (process “D”) and the door is restored on the empty first pod (process “E”), which is then replaced with another pod carrying unprocessed wafer (process “A”), the new pod remaining at the first wafer loading port until the wafer loading process at the second wafer loading port is completed (process “F”). The processes described in connection with the third stage are alternately carried out until all the required wafers for one batch process are transferred to the wafer boat 8.
As described above in the second embodiment of the present invention, the pod transferring process “A” and the pod changing process “A” for one wafer loading port are carried out during the wafer transferring process “D” at the other wafer loading port; and the pod door opening process “B” for one wafer loading port and the pod door closing process “E” for the other wafer loading port are simultaneously conducted.
The process sequence of the second embodiment for transferring processed wafers to empty pods is identical to that for transferring unprocessed wafers to the wafer boat 8, excepting that the pod changing process “A” in the process sequence for transferring processed wafers represents the process of transferring a pod containing the processed wafers from a wafer loading port to the pod shelf 12 and then moving an empty pod from the pod shelf 12 to that wafer loading port. The process “A” of transferring a first empty wafer to one of the wafer loading ports is controlled in such a manner that the wafer transferring from the boat to the first empty pod can be conducted immediately after completing the opening of the door of the first pod.
The sequence shown in
Following advantages can be achieved in accordance with the present invention.
In contrast, the pod openers 20 in accordance with the present invention solely operate along horizontal directions and do not contribute at all to the height increase of the equipment and the pod-transfer time. Further, the pod shelf is arranged to receive two columns of pods along the width direction of the processing equipment, whereas only one column of wafer transferring ports is provided under the pod shelf. As a result, the purely transitional lateral motion of the pod openers can be accommodated by the reserved space under the pod shelf and, therefore, the system efficiency and the throughput can be improved without increasing the pod transfer time and sacrificing the floor area of the processing equipment.
It is to be appreciated that the configuration of the semiconductor processing equipment may be varied appropriately if necessary.
For instance, the number of the wafer loading ports is not limited to two but more than two wafer loading ports can be installed vertically of if the height increase can be accommodated.
In addition, in lieu of the rotary actuator for actuating the mapping device, another mechanism using an X-Y axis robot can be employed. Moreover, the mapping device can be omitted if so required.
Furthermore, the processing equipment can be of the type capable of processing other substrates, e.g., photo masks, printed circuit boards, liquid crystal panels, compact disks and magnetic disk, than the semiconductor wafers.
The processing equipment can be of the type adapted to perform, e.g., oxide formation, diffusion process and other types of heat treating process in place of the CVD. The present invention is also applicable to other types of semiconductor processing equipments than the batch type vertical processor.
While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
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|U.S. Classification||414/217, 414/810, 414/940|
|International Classification||F26B21/06, H01L21/677, B65G49/07|
|Cooperative Classification||Y10S414/14, H01L21/67775, H01L21/67772|
|European Classification||H01L21/677D8, H01L21/677D6|