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Publication numberUS20040118694 A1
Publication typeApplication
Application numberUS 10/438,624
Publication dateJun 24, 2004
Filing dateMay 14, 2003
Priority dateDec 19, 2002
Also published asWO2004057060A2, WO2004057060A3
Publication number10438624, 438624, US 2004/0118694 A1, US 2004/118694 A1, US 20040118694 A1, US 20040118694A1, US 2004118694 A1, US 2004118694A1, US-A1-20040118694, US-A1-2004118694, US2004/0118694A1, US2004/118694A1, US20040118694 A1, US20040118694A1, US2004118694 A1, US2004118694A1
InventorsMichael Yang, Ming Xi, Russell Ellwanger, Eric Britcher
Original AssigneeApplied Materials, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Multi-chemistry electrochemical processing system
US 20040118694 A1
Abstract
Embodiments of the invention generally provide an electrochemical processing system configured to provide multiple chemistries for a single plating process. The multiple chemistries are generally delivered to individual plating cells positioned on the processing system. The individual chemistries may generally be used to conduct direct plating on a barrier layer, alloy plating, plating on a thin seed layer, optimized feature fill and bulk fill plating, plating with minimized defects, and/or any other plating process wherein multiple chemistries may be utilized to take advantage of the desirable characteristics of each chemistry.
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Claims(31)
What is claimed is:
1. An electrochemical processing system, comprising:
a system platform having a plurality of processing cells positioned thereon;
at least one robot positioned to transfer substrates between the plurality of processing cells; and
a fluid delivery system in fluid communication with each of the plurality of processing cells, the fluid delivery system being configured to provide multiple chemistries to each of the plurality of processing cells.
2. The electrochemical processing cell of claim 1, wherein the fluid delivery system comprises:
a first plurality of additive sources;
a metered pump in fluid communication with each of the additive sources;
a first virgin electrolyte source in fluid communication with the metered pump; and
a manifold in fluid communication with the metered pump at an input and with the plurality of processing cells at an output, the manifold being configured to direct a specific chemistry to a selected one of the plurality of processing cells.
3. The electrochemical processing cell of claim 1, further comprising a second plurality of additive sources and a second virgin electrolyte source, both the second plurality of additive sources and the second virgin electrolyte source being in fluid communication with a manifold that is selectively in fluid communication with the plurality of processing cells.
4. The apparatus of claim 2, wherein the first plurality of additive sources further comprise:
a first source for providing an electrochemical plating accelerator;
a second source for providing an electrochemical plating leveler; and
a third source for providing an electrochemical plating suppressor.
5. The apparatus of claim 2, wherein the first plurality of additive sources further comprises:
at least one bulk additive container; and
at least one buffer container having a volume less than the bulk additive container and being in fluid communication with an associated bulk additive container and the metered pump.
6. The electrochemical processing cell of claim 1, wherein at least two of the plurality of processing cells comprise electrochemical plating cells.
7. The electrochemical processing cell of claim 1, wherein at least one of the plurality of processing cells comprise a spin rinse dry processing cell.
8. The electrochemical processing cell of claim 1, wherein at least one of the plurality of processing cells comprise a substrate bevel edge clean processing cell.
9. The electrochemical processing cell of claim 1, further comprising at least one annealing chamber in communication with the system platform.
10. The electrochemical processing cell of claim 9, wherein the anneal chamber includes at least one heating position and at least one cooling position.
11. The electrochemical processing cell of claim 10, wherein the annealing chamber further comprises a substrate transfer robot positioned between the at least one heating position and the at least one cooling position, the substrate transfer robot is configured to transfer substrates between the heating and cooling positions.
12. The electrochemical processing system of claim 1, wherein the fluid delivery system is further configured to supply an anolyte to an anode chamber of at least one plating cell positioned on the system platform.
13. An electrochemical processing system, comprising:
a processing system base having a plurality of process cell locations thereon;
at least two electrochemical plating cells positioned at two of the process cell locations;
at least one spin rinse dry cell positioned at one of the process cell locations;
at least one substrate bevel clean cell positioned at another one of the process cell locations; and
a multiple chemistry plating solution delivery system in fluid communication with the at least two electrochemical processing cells, the multiple chemistry plating solution delivery system comprising:
a metering pump;
a plurality of plating solution additive containers in fluid communication with the metering pump;
at least one first virgin electrolyte solution container in fluid communication with the metering pump; and
a plating solution distribution manifold in fluid communication with an output of the metering pump and selectively in individual fluid communication with each of the at least two electrochemical plating cells.
14. The electrochemical processing system of claim 13, further comprising a factory interface in communication with the processing system base.
15. The electrochemical processing system of claim 13, further comprising at least one annealing chamber in communication with at least one of the factory interface and the processing base.
16. The electrochemical processing system of claim 15, wherein the at least one annealing chamber comprises a heating location, a cooling location, and a robot positioned to transfer substrates between the heating location and the cooling location.
17. The electrochemical processing system of claim 13, wherein the plurality of plating solution additive containers comprise a bulk container in fluid communication with a buffer container, the buffer container being in fluid communication with the metering pump.
18. The electrochemical processing system of claim 13, wherein the metering pump comprises a precise fluid delivery pump having a plurality of inputs and at least one output, the metering pump being configured to mix a predetermined ratio of fluid components received at the plurality of inputs and output the predetermined ratio of fluid components from the at least one output.
19. The electrochemical processing system of claim 13, wherein the multiple chemistry plating solution delivery system further comprises a second virgin electrolyte solution container in fluid communication with the metering pump, the second virgin electrolyte solution container being configured to provide a second virgin electrolyte that is different from a first virgin electrolyte contained in the at least one first virgin electrolyte container.
20. An electrochemical processing system, comprising:
a plurality of electrochemical processing cells positioned on a system base; and
means for delivering a plurality different electrochemical plating solutions to each of the plurality of electrochemical processing cells.
21. The electrochemical processing system of claim 20, further comprising:
a factory interface location in communication with the system base;
at least one substrate rinse and spin location positioned on the system base;
at least one substrate bevel clean location positioned on the system base;
an annealing location positioned in communication with the system base; and
at least one substrate transfer robot positioned to transfer substrates between various locations of the electrochemical processing system.
22. A method for electrochemically plating at least one layer onto a semiconductor substrate, comprising:
positioning the substrate in a first electrochemical plating cell on a unitary plating system platform for a first plating operation;
positioning the substrate in a second plating cell on the unitary plating system platform for a second plating operation;
supplying a first electrochemical plating chemistry to the first plating cell with a multiple chemistry fluid delivery system; and
supplying a second electrochemical plating chemistry to the second plating cell with the multiple chemistry fluid delivery system, wherein the first and second chemistries are different.
23. The method of claim 22, wherein the first and second electrochemical plating chemistries have different virgin makeup solution bases.
24. The method of claim 22, wherein the first and second electrochemical plating chemistries have different additive concentrations.
25. The method of claim 22, wherein the first electrochemical plating chemistry is an optimized gap fill chemistry and wherein the second electrochemical plating chemistry is an optimized bulk fill chemistry.
26. The method of claim 22, wherein the first electrochemical plating chemistry is an optimized plating on barrier chemistry and wherein the second electrochemical plating chemistry is an optimized feature fill planarization chemistry.
27. The method of claim 22, wherein the first electrochemical plating chemistry is an optimized alloy plating chemistry and wherein the second electrochemical plating chemistry is an optimized copper plating chemistry.
28. The method of claim 22, further comprising rinsing the semiconductor substrate between the first plating operation and the second plating operation.
29. The method of claim 28, further comprising spin drying the semiconductor substrate between the first plating operation and the second plating operation.
30. The method of claim 22, wherein the first plating operation is a copper plating process and the second plating operation is an alloy plating process.
31. The method of claim 22, wherein the first plating operation comprises a defect reduction plating process.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. provisional patent application serial No. 60/435,121, filed Dec. 19, 2002, which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] Embodiments of the invention generally relate to an electrochemical processing system and methods for electrochemically depositing conductive materials on substrates.

[0004] 2. Description of the Related Art

[0005] Metallization of sub-quarter micron sized features is a foundational technology for present and future generations of integrated circuit manufacturing processes. More particularly, in devices such as ultra large scale integration-type devices, i.e., devices having integrated circuits with more than a million logic gates, the multilevel interconnects that lie at the heart of these devices are generally formed by filling high aspect ratio, i.e., greater than about 4:1, interconnect features with a conductive material, such as copper or aluminum. Conventionally, deposition techniques such as chemical vapor deposition (CVD) and physical vapor deposition (PVD) have been used to fill these interconnect features. However, as the interconnect sizes decrease and aspect ratios increase, void-free interconnect feature fill via conventional metallization techniques becomes increasingly difficult. Therefore, plating techniques, i.e., electrochemical plating (ECP) and electroless plating, have emerged as promising processes for void free filling of sub-quarter micron sized high aspect ratio interconnect features in integrated circuit manufacturing processes.

[0006] In an ECP process, for example, sub-quarter micron sized high aspect ratio features formed into the surface of a substrate (or a layer deposited thereon) may be efficiently filled with a conductive material, such as copper. ECP plating processes are generally two stage processes, wherein a seed layer is first formed over the surface features of the substrate, and then the surface features of the substrate are exposed to an electrolyte solution, while an electrical bias is applied between the seed layer and a copper anode positioned within the electrolyte solution. The electrolyte solution generally contains ions to be plated onto the surface of the substrate, and therefore, the application of the electrical bias causes these ions to be urged out of the electrolyte solution and to be plated onto the biased seed layer, thus depositing a layer of the ions on the substrate surface that may fill the features.

[0007] Filling of surface features, such as vias and trenches, as quickly as possible without forming defects in the fill layer is desirable to promote throughput of semiconductor device manufacturing processes. However, plating chemistries that generally increase feature filling rates often produce films having poor planarity and high defect ratios. For example, chemistries configured to rapidly deposit material over closely spaced features generally builds in thickness from the upper corners of the features and eventually meets across the top of the feature, creating a high spot relative to the surrounding film. Moreover, if the material builds from the upper corners of the features too rapidly, the openings of the features may close off and voids may be formed. Conversely, chemistries that promote planarization and substantially defect free films generally have slow plating rates, which keeps the upper portion of features open, but inherently slows throughput. Therefore, conventional electrochemical plating chemistries are generally configured to balance or compromise the feature filling performance with defect and planarization characteristics. More particularly, the chemistry in a plating cell is generally configured to provide acceptable feature fill rates to facilitate throughput, while also providing minimal defects. However, since the chemistry must balance the needs of two separate processes with differing goals, the chemistry must inherently sacrifice some characteristics in each of the processes, i.e., increases in throughput are generally at the expense of the defect ratio.

[0008] However, it would be desirable to provide a plating system that could provide multiple chemistry capability so that the advantageous characteristics of multiple chemistries may be incorporated into a single plating process. In addition to having application to feature fill and bulk fill processes, a system having the multiple chemistry capability would also provide advantages to various other plating processes that conventionally are required to balance the plating characteristics of a single chemistry plating process. For example, a multiple chemistry plating system would facilitate plating directly on barrier layers, as a first plating chemistry could be used to facilitate adhesion to the barrier layer (generally a slow plating process) and then a second chemistry could be used plate over the layer on top of the barrier layer and fill the features without adhesion challenges. Further, a multiple chemistry system would also be beneficial to an alloy plating process, wherein a first chemistry could be used to plate the alloy layer and then a second chemistry could be used to plate a different layer or another alloy layer over the previously deposited layer. Further still, a multiple chemistry process could be used to substantially improve defect ratios in semiconductor substrate plating processes via utilization of a first chemistry configured to plate a first layer with minimal defects (generally at a slower rate) and then a second chemistry configured to plate a second layer over the first layer with minimal defects in manner that optimizes throughput.

[0009] Therefore, there is a need for an improved electrochemical plating system configured to provide multiple chemistries for a single electrochemical plating process.

SUMMARY OF THE INVENTION

[0010] Embodiments of the invention generally provide an electrochemical processing system configured to provide multiple chemistries for a single plating process. The multiple chemistries may be used to conduct direct plating on a barrier layer, alloy plating, plating on a thin seed layer, optimized feature fill and bulk fill plating, plating with minimized defects, and/or any other plating process wherein multiple chemistries may be utilized to take advantage of the characteristics of each chemistry. The multiple chemistries are generally provided to separate electrochemical processing cells positioned on a unitary electrochemical plating system.

[0011] Embodiments of the invention further provide an electrochemical processing system, wherein the system includes a system platform having a plurality of processing cells positioned thereon, a robot positioned to transfer substrates between the plurality of processing cells, and a factory interface positioned in communication with the system platform, the factory interface being configured to provide substrates to system platform for processing. The system further includes a fluid delivery system in fluid communication with each of the plurality of processing cells, the fluid delivery system being configured to provide multiple chemistries to each of the plurality of processing cells.

[0012] Embodiments of the invention may further provide an electrochemical processing system. The processing system may include a processing system base having a plurality of process cell locations thereon, at least two electrochemical plating cells positioned at two of the process cell locations, at least one spin rinse dry cell positioned at one of the process cell locations, and at least one substrate bevel clean cell positioned at another one of the process cell locations. The processing system may further include a multiple chemistry plating solution delivery system in fluid communication with the at least two electrochemical processing cells. The multiple chemistry plating solution delivery system generally includes a metering pump, a plurality of plating solution additive containers in fluid communication with the metering pump, at least one first virgin electrolyte solution container in fluid communication with the metering pump, and a plating solution distribution manifold in fluid communication with an output of the metering pump and selectively in individual fluid communication with each of the at least two electrochemical plating cells.

[0013] Embodiments of the invention may further provide an electrochemical processing system having a plurality of electrochemical processing cells positioned on a system base and means for delivering a plurality different electrochemical plating solutions to each of the plurality of electrochemical processing cells.

[0014] Embodiments of the invention may further provide a method for electrochemically plating at least one layer onto a semiconductor substrate. The method generally includes positioning the substrate in a first electrochemical plating cell on a unitary plating system platform for a first plating operation, positioning the substrate in a second plating cell on the unitary plating system platform for a second plating operation, supplying a first electrochemical plating chemistry to the first plating cell with a multiple chemistry fluid delivery system, and supplying a second electrochemical plating chemistry to the second plating cell with the multiple chemistry fluid delivery system, wherein the first and second chemistries are different.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

[0016]FIG. 1 is a top plan view of one embodiment of an electrochemical plating system of the invention.

[0017]FIG. 2A is a partial sectional view of one embodiment of an electrochemical process cell.

[0018]FIG. 2B is a partial sectional view of another embodiment of an electrochemical process cell.

[0019]FIG. 3 is a schematic diagram of one embodiment of a plating solution delivery system.

[0020]FIG. 4 is a partial sectional view of one embodiment of a process cell configured to remove deposited material from an edge of a substrate.

[0021]FIG. 5 is a partial sectional view of one embodiment of a process cell configured to spin, rinse and dry a substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] Embodiments of the invention generally provide an electrochemical plating system configured to plate conductive materials, such as metals, on a semiconductor substrate using multiple chemistries. The implementation of multiple chemistries on a single plating platform allows for optimization of multiple process steps, which results in enhanced film qualities and improved system throughput. Embodiments of the invention contemplate that the multiple chemistry system may be used for various plating processes, including, but not limited to direct plating on a barrier layer, alloy plating, alloy plating combined with convention metal plating, plating on a thin seed layer, optimized feature fill and bulk fill plating, plating multiple layers with minimal defects, or any other plating process where more than one chemistry may be beneficial to a plating process.

[0023]FIG. 1 is a top plan view of one embodiment of an electrochemical processing system (ECP) 100 of the present invention. ECP system 100 generally includes a processing base 113 having a robot 120 centrally positioned thereon. The robot 120 generally includes one or more robot arms 122, 124 configured to support substrates thereon. Additionally, the robot 120 and the accompanying blades 122, 124 are generally configured extend, rotate, and vertically move so that the robot 120 may insert and remove substrates to and from a plurality of processing locations 102, 104, 106, 108, 110, 112, 114, 116 positioned on the base 113.

[0024] ECP system 100 further includes a factory interface (FI) 130. FI 130 generally includes at least one FI robot 132 positioned adjacent a side of the FI that is adjacent the processing base 113. This position of robot 132 allows the robot to access substrate cassettes 134 to retrieve a substrate 126 therefrom and then deliver the substrate 126 to one of processing cells 114, 116 to initiate a processing sequence. Similarly, robot 132 may be used to retrieve substrates from one of the processing cells 114, 116 after a substrate processing sequence is complete. In this situation robot 132 may deliver the substrate 126 back to one of the cassettes 134 for removal from the system 100. Additionally, robot 132 is also configured to access an anneal chamber 135 positioned in communication with FI 130. The anneal chamber 135 generally includes a two position annealing chamber, wherein a cooling plate or position 136 and a heating plate or position 137 are positioned adjacently with a substrate transfer robot 140 positioned proximate thereto, e.g., between the two stations. The robot 140 is generally configured to move substrates between the respective heating 137 and cooling plates 136.

[0025] Generally, process locations 102, 104, 106, 108, 110, 112, 114, 116 may be any number of processing cells utilized in an electrochemical plating platform. More particularly, the process locations may be configured as electrochemical plating cells, rinsing cells, bevel clean cells, spin rinse dry cells, substrate surface cleaning cells, electroless plating cells, metrology inspection stations, and other cells or processes that may be beneficially used in conjunction with a plating platform.

[0026]FIG. 2A is a cross sectional view of one embodiment of a processing cell (FIG. 2A illustrates an exemplary electrochemical plating cell) that may be implemented in any one of processing locations 102, 104, 106, 108, 110, 112, 114, 116 of processing system 100. Generally, however, the exemplary processing system 100 is configured to include four electrochemical plating cells at processing locations 102, 104, 112, and 110. Processing locations 106 and 108 are generally configured as edge bead removal or bevel clean chambers. Further, processing locations 114 and 116 are generally configured as substrate surface cleaning chambers and spin rinse dry chambers, which may be positioned in a stacked manner, i.e., one above the other. However, the invention is not intended to be limited to any particular order or arrangement of cells, as various combinations and arrangements may be implemented without departing from the scope of the invention.

[0027] Returning to FIG. 2A, the electrochemical processing cell 102 generally includes a head assembly 220, an anode assembly 220, an inner basin 272, and an outer basin 240. The outer basin 240 is coupled to the base and circumscribes the inner basin 272. The inner and outer basins 272, 240 are typically fabricated from an electrically insulative material compatible with process chemistries, for example, ceramics, plastics, plexiglass (acrylic), lexane, PVC, CPVC or PVDF. Alternatively, the inner and outer basins 272, 240 may be made from a metal, such as stainless steel, nickel or titanium, which is coated with an insulating layer, such as Teflon®, fluoropolymer, PVDF, plastic, rubber and other combinations of materials compatible with plating fluids and can be electrically insulated from the electrodes (i.e., the anode and cathode of the electroplating system). The inner basin 272 is typically configured to conform to the substrate plating surface and the shape of the substrate being processed through the system, generally having a circular or rectangular shape. In one embodiment, the inner basin 272 is a cylindrical ceramic tube having an inner diameter that has about the same dimension as or slightly larger than the diameter of a substrate being plated in the cell 102. The outer basin 272 generally includes a channel 248 for catching plating fluids flowing out of the inner basin 272. The outer basin 272 also has a drain 218 formed therethrough that couples the channel 248 to a reclamation system for processing, recycling and/or disposal of used plating fluids.

[0028] The head assembly 220 is mounted to a head assembly frame 252. The head assembly frame 252 includes a mounting post 254 and a cantilever arm 256. The mounting post 254 is coupled to the base of the processing system 100 and the cantilever arm 256 extends laterally from an upper portion of the mounting post 254 and is generally adapted to rotate about a vertical axis of the mounting post 254 to allow movement of the head assembly 220 over or clear of the basins 240, 272. The head assembly 220 is generally attached to a mounting plate 260 disposed at the distal end of the cantilever arm 256. The lower end of the cantilever arm 256 is connected to a cantilever arm actuator 268, such as a pneumatic cylinder, mounted on the mounting post 254. The cantilever arm actuator 268 provides pivotal movement of the cantilever arm 256 with respect to the joint between the cantilever arm 256 and the mounting post 254. When the cantilever arm actuator 268 is retracted, the cantilever arm 256 moves the head assembly 220 away from the anode assembly 220 disposed in the inner basin 272 to provide the spacing required to remove and/or replace the anode assembly 220 from the first process cell 102. When the cantilever arm actuator 268 is extended, the cantilever arm 256 moves the head assembly 220 axially toward the anode assembly 220 to position the substrate in the head assembly 220 in a processing position. The head assembly 220 may also tilt to orientate a substrate held therein in at an angle from horizontal.

[0029] The head assembly 220 generally includes a substrate holder assembly 250 and a substrate assembly actuator 258. The substrate assembly actuator 258 is mounted onto the mounting plate 260, and includes a head assembly shaft 262 that extends downwardly through the mounting plate 260. The lower end of the head assembly shaft 262 is connected to the substrate holder assembly 250 to position the substrate holder assembly 250 in a processing position and in a substrate loading position. The substrate assembly actuator 258 additionally may be configured to provide rotary motion to the head assembly 220. In one embodiment, the head assembly 220 is rotated between about 2 rpm and about 50 rpm during an electroplating process, and may be rotated between about 5 and about 20 rpm. The head assembly 220 can also be rotated as the head assembly 220 is lowered to position the substrate in contact with the plating solution in the process cell as well as when the head assembly 220 is raised to remove the substrate from the plating solution in the process cell. The head assembly 220 may be rotated at a high speed (i.e., >20 rpm) after the head assembly 220 is lifted from the process cell to enhance removal of residual plating solution from the head assembly 220 and substrate.

[0030] The substrate holder assembly 250 generally includes a thrust plate 264 and a cathode contact ring 266. The cathode contact ring 266 is configured to electrically contact the surface of the substrate to be plated. Typically, the substrate has a seed layer of metal, such as copper, deposited on the feature side of the substrate. A power source 246 is coupled between the cathode contact ring 266 and the anode assembly 220 and provides an electrical bias that drives the plating process.

[0031] The thrust plate 264 and the cathode contact ring 266 are suspended from a hanger plate 236. The hanger plate 236 is coupled to the head assembly shaft 262. The cathode contact ring 266 is coupled to the hanger plate 236 by hanger pins 238. The hanger pins 238 allows the cathode contact ring 266 when mated against the inner basin 272, to move to closer to the hanger plate 236, thus allowing the substrate held by the thrust plate 264 to be sandwiched between the hanger plate 236 and thrust plate 264 during processing, thereby ensuring good electrical contact between the seed layer of the substrate and the cathode contact ring 266.

[0032] The anode assembly 220 is generally positioned within a lower portion of the inner basin 272 below the substrate holder assembly 250. The anode assembly 220 generally includes one or more anodes 244 and a diffusion plate 222. The anode 244 is typically disposed in the lower end of the inner basin 272 and the diffusion plate 222 is disposed between the anode 244 and the substrate held by the substrate holder assembly 250 at the top of the inner basin 272. The anode 244 and diffusion plate 222 are generally maintained in a spaced-apart relation by insulative spacer 224. The diffusion plate 222 is typically attached to and substantially spans the inner opening of the inner basin 272. The diffusion plate 222 is generally permeable to the plating solution and is typically fabricated from a plastic or ceramic material, for example an olefin such as a spunbonded polyester film. The diffusion plate 222 generally operates as a fluid flow restrictor to improve flow uniformity across the surface of the substrate 112 being plated. The diffusion plate 222 also operates to damp electrical variations in the electrochemical cell, i.e., to control electrical flux, which improves plating uniformity. Alternatively, the diffusion plate 222 may be fabricated from a hydrophilic plastic, such as treated PE, PVDF, PP, or other porous or permeable material that provides electrically resistive damping characteristics.

[0033] The anode assembly 220 may include a consumable anode 244 that serves as a metal source for the plating process. Alternatively, the anode 244 may be a non-consumable anode, and the metal to be electroplated is supplied within the plating solution from the plating solution delivery system 111. The anode assembly 220 may be a self-enclosed module having a porous enclosure preferably made of the same metal as the metal to be electroplated, such as copper. Alternatively, the enclosure may be fabricated from porous materials, such as ceramics or polymeric membranes. Exemplary consumable and non-consumable anodes include copper/doped copper and platinum, respectively. The anode 244 is typically metal particles, wires, and/or a perforated sheet and is typically manufactured from the material to be deposited on the substrate, such as copper, aluminum, gold, silver, platinum, tungsten, copper phosphate, noble metal or other materials which can be electrochemically deposited on the substrate. The anode 244 may be porous, perforated, permeable or otherwise configured to allow passage of the plating solution therethrough. Alternatively, the anode 244 may be solid. As compared to a non-consumable anode, the consumable (i.e., soluble) anode provides gas-generation-free plating solution and minimizes the need to constantly replenish the metal in the plating solution. In the embodiment depicted in FIG. 2A, the anode 244 is a solid copper disk.

[0034] An electrolyte inlet 216 is formed through the inner basin 272 and is coupled to the plating solution delivery system 111. The plating solution entering the inner basin 272 through the electrolyte inlet 216 flows through or around the anode assembly 220 upward toward the surface of the substrate 112 positioned on the upper end of the inner basin 272. The plating solution flows across the substrate's surface and through slots (not shown) in the cathode contact ring 266 to a passage formed in the outer basin 240. The bias applied by the power source 246 between the substrate (through the cathode contact ring 266) and the anodes 244 causes metal ions from the plating fluids and/or anode to deposit on the surface of the substrate. Examples of process cells that may be adapted to benefit from the invention are described in U.S. patent application Ser. No. 09/905,513, filed Jul. 13, 2001, and in U.S. patent application Ser. No. 10/061,126, filed Jan. 30, 2002, both of which incorporated by reference in their entireties.

[0035]FIG. 2B is partial sectional view of another embodiment of an exemplary processing cell, and more particularly, an exemplary electrochemical plating cell 200. The electrochemical plating cell 200 generally includes an outer basin 201 and an inner basin 202 positioned within outer basin 201. Inner basin 202 is generally configured to contain a plating solution that is used to plate a metal, e.g., copper, onto a substrate during an electrochemical plating process. During the plating process, the plating solution is generally continuously supplied to inner basin 202 (at about 1 gallon per minute for a 10 liter plating cell, for example), and therefore, the plating solution continually overflows the uppermost point of inner basin 202 and runs into outer basin 201. The overflow plating solution is then collected by outer basin 201 and drained therefrom for recirculation into inner basin 202. Plating cell 200 is generally positioned at a tilt angle, i.e., the frame portion 203 of plating cell 200 is generally elevated on one side such that the components of plating cell 200 are tilted between about 3° and about 30°. Therefore, in order to contain an adequate depth of plating solution within inner basin 202 during plating operations, the uppermost portion of basin 202 may be extended upward on one side of plating cell 200, such that the uppermost point of inner basin 202 is generally horizontal and allows for contiguous overflow of the plating solution supplied thereto around the perimeter of basin 202.

[0036] The frame member 203 of plating cell 200 generally includes an annular base member 204 secured to frame member 203. Since frame member 203 is elevated on one side, the upper surface of base member 204 is generally tilted from the horizontal at an angle that corresponds to the angle of frame member 203 relative to a horizontal position. Base member 204 includes an annular or disk shaped recess formed therein, the annular recess being configured to receive a disk shaped anode member 205. Base member 204 further includes a plurality of fluid inlets/drains 209 positioned on a lower surface thereof. Each of the fluid inlets/drains 209 are generally configured to individually supply or drain a fluid to or from either the anode compartment or the cathode compartment of plating cell 200. Anode member 205 generally includes a plurality of slots 207 formed therethrough, wherein the slots 207 are generally positioned in parallel orientation with each other across the surface of the anode 205. The parallel orientation allows for dense fluids generated at the anode surface to flow downwardly across the anode surface and into one of the slots 207. Plating cell 200 further includes a membrane support assembly 206. Membrane support assembly 206 is generally secured at an outer periphery thereof to base member 204, and includes an interior region configured to allow fluids to pass therethrough. A membrane 208 is stretched across the support 206 and operates to fluidly separate a catholyte chamber and anolyte chamber portions of the plating cell. The membrane support assembly may include an o-ring type seal positioned near a perimeter of the membrane, wherein the seal is configured to prevent fluids from traveling from one side of the membrane secured on the membrane support 206 to the other side of the membrane. A diffusion plate 210 is positioned above the membrane 208 and is configured similarly to diffusion member 222 illustrated in FIG. 2A.

[0037] In operation, assuming a tilted implementation is utilized, the plating cell 200 will generally immerse a substrate into a plating solution contained within inner basin 202. Once the substrate is immersed in the plating solution, which generally contains copper sulfate, chlorine, and one or more of a plurality of organic plating additives (levelers, suppressors, accelerators, etc.) configured to control plating parameters, an electrical bias is applied between a seed layer on the substrate and the anode 205 positioned in the plating cell. The electrical bias is generally configured to cause metal ions moving through the plating solution to deposit on the cathodic substrate surface. In this embodiment of the plating cell 200, separate fluid solutions are supplied to the volume above the membrane 208 and the volume below the membrane 208. Generally, the volume above the membrane is designated the cathode compartment or region, as this region is where the cathode electrode or plating electrode is positioned. Similarly, the volume below the membrane 208 is generally designated the anode compartment or region, as this is the region where the anode is located. The respective anode and cathode regions are generally fluidly isolated from each other via membrane 208 (which is generally an ionic membrane). Thus, the fluid supplied to the cathode compartment is generally a plating solution containing all the required constituents to support plating operations, while the fluid supplied to the anode compartment is generally a solution that does not contain the plating solution additives that are present in the cathode chamber, e.g., copper sulfate solutions, for example. Additional detail with respect to the configuration and operation of the exemplary plating cell illustrated in FIG. 2B may be found in commonly assigned U.S. patent application Ser. No. 10/268,284, entitled “ELECTROCHEMICAL PROCESSING CELL”, filed on Oct. 9, 2002.

[0038]FIG. 3 is a schematic diagram of one embodiment of the plating solution delivery system 111. The plating solution delivery system 111 is generally configured to supply a plating solution to each processing location on system 100 that requires the solution. More particularly, the plating solution delivery system is further configured to supply a different plating solution or chemistry to each of the processing locations. For example, the delivery system may provide a first plating solution or chemistry to processing locations 110, 112, while providing a different plating solution or chemistry to processing locations 102, 104. The individual plating solutions are generally isolated for use with a single plating cell, and therefore, there are no cross contamination issues with the different chemistries. However, embodiments of the invention contemplate that more than one cell may share a common chemistry that is different from another chemistry that is supplied to another plating cell on the system. These features are advantageous, as the ability to provide multiple chemistries to a single processing platform allows for multiple chemistry plating processes on a single platform.

[0039] In another embodiment of the invention, a first plating solution and a separate and different second plating solution can be provided sequentially to a single plating cell. Typically, providing two separate chemistries to a single plating cell requires the plating cell to be drained and/or purged between the respective chemistries, however, a mixed ratio of less than about 10 percent first plating solution to the second plating solution should not be detrimental to film properties.

[0040] More particularly, the plating solution delivery system 111 typically includes a plurality of additive sources 302 and at least one electrolyte source 304 that are fluidly coupled to each of the processing cells of system 100 via a manifold 332. Typically, the additive sources 302 include an accelerator source 306, a leveler source 308, and a suppressor source 310. The accelerator source 306 is adapted to provide an accelerator material that typically adsorbs on the surface of the substrate and locally accelerates the electrical current at a given voltage where they adsorb. Examples of accelerators include sulfide-based molecules. The leveler source 308 is adapted to provide a leveler material that operates to facilitate planar plating. Examples of levelers are nitrogen containing long chain polymers. The suppressor source 310 is adapted to provide suppressor materials that tend to reduce electrical current at the sites where they adsorb (typically the upper edges/corners of high aspect ratio features). Therefore, suppressors slow the plating process at those locations, thereby reducing premature closure of the feature before the feature is completely filled and minimizing detrimental void formation. Examples of suppressors include polymers of polyethylene glycol, mixtures of ethylene oxides and propylene oxides, or copolymers of ethylene oxides and propylene oxides.

[0041] In order to prevent situations where an additive source runs out and to minimize additive waste during bulk container replacement, each of the additive sources 302 generally includes a bulk or larger storage container coupled to a smaller buffer container 316. The buffer container 316 is generally filled from the bulk storage container 314, and therefore, the bulk container may be removed for replacement without affecting the operation of the fluid delivery system, as the associated buffer container may supply the particular additive to the system while the bulk container is being replaced. The volume of the buffer container 316 is typically much less than the volume of the bulk container 314. It is sized to contain enough additive for 10 to 12 hours of uninterrupted operation. This provides sufficient time for operators to replace the bulk container when the bulk container is empty. If the buffer container was not present and uninterrupted operation was still desired, the bulk containers would have to be replaced prior to being empty, thus resulting in significant additive waste.

[0042] In the embodiment depicted in FIG. 3, a dosing pump 312 is coupled between the plurality of additive sources 302 and the plurality of processing cells. The dosing pump 312 generally includes at least a first through fourth inlet ports 322, 324, 326, 328. As an example, the first inlet port 322 is generally coupled to the accelerators source 306, the second inlet port 324 is generally coupled to the leveler source 308, the third inlet port 326 is generally coupled to the suppressor source 310, and the fourth inlet port 328 is generally coupled to the electrolyte source 304. An output 330 of the dosing pump 312 is generally coupled to the processing cells via manifold 332 by an output line 340 wherein mixing of the sequentially supplied additives (i.e., at least one or more accelerators, levelers and/or suppressors) may be combined with electrolyte provided to the manifold 332 through a first delivery line 350 from the electrolyte source 304, to form the first or second plating solutions as desired. The dosing pump 312 may be any metering device(s) adapted to provide measured amounts of selective additives to the process cells 102, 104. The dosing pump 312 may be a rotary metering valve, a solenoid metering pump, a diaphragm pump, a syringe, a peristaltic pump, or other positive displacement pumps used singularly or coupled to a flow sensor. In addition, the additives could be pressurized and coupled to a flow sensor, coupled to a liquid mass flow controller, or metered by weight utilizing load cell measurement of the pressurized dispense vessel or other fluid metering devices acceptable for flowing electrochemical plating solutions to a plating cell. In one embodiment, the dosing pump includes a rotating and reciprocating ceramic piston that drives 0.32 ml per cycle of a predetermined additive.

[0043] In another embodiment of the invention the fluid delivery system may be configured to provide a second completely different plating solution and associated additives. For example, in this embodiment a different base electrolyte solution (similar to the solution contained in container 304) may be implemented to provide the processing system 100 with the ability, for example, to use plating solutions from two separate manufacturers. Further, an additional set of additive containers may also be implemented to correspond with the second base plating solution. Therefore, this embodiment of the invention allows for a first chemistry (a chemistry provided by a first manufacturer) to be provided to one or more plating cells of system 100, while a second chemistry (a chemistry provided by a second manufacturer) is provided to one or more plating cells of system 100. Each of the respective chemistries will generally have their own associated additives, however, cross dosing of the chemistries from a single additive source or sources is not beyond the scope of the invention.

[0044] In order to implement the fluid delivery system capable of providing two separate chemistries from separate base electrolytes, a duplicate of the fluid delivery system illustrated in FIG. 3 is connected to the processing system. More particularly, the fluid delivery system illustrated in FIG. 3 is generally modified to include a second set of additive containers 302, a second pump assembly 330, and a second manifold 332 (shared manifolds are possible). Additionally, separate sources for virgin makeup solution/base electrolyte 304 are also provided. The additional hardware is set up in the same configuration as the hardware illustrated in FIG. 3, however, the second fluid delivery system is generally in parallel with the illustrated or first fluid delivery system. Thus, with this configuration implemented, either base chemistry with any combination of the available additives may be provided to any one or more of the processing cells of system 100.

[0045] The manifold 332 is typically configured to interface with a bank of valves 334. Each valve of the valve bank 334 may be selectively opened or closed to direct fluid from the manifold 332 to one of the process cells of the plating system 100. The manifold 332 and valve bank 334 may optionally be configured to support selective fluid delivery to additional number of process cells. In the embodiment depicted in FIG. 3, the manifold 332 and valve bank 334 include a sample port 336 that allows different combinations of chemistries or component thereof utilized in the system 100 to be sampled without interrupting processing.

[0046] In some embodiments, it may be desirable to purge the dosing pump 312, output line 340 and/or manifold 332. To facilitate such purging, the plating solution delivery system 111 is configured to supply at least one of a cleaning and/or purging fluid. In the embodiment depicted in FIG. 3, the plating solution delivery system 111 includes a deionized water source 342 and a non-reactive gas source 344 coupled to the first delivery line 350. The non-reactive gas source 344 may supply a non-reactive gas, such as an inert gas, air or nitrogen through the first delivery line 350 to flush out the manifold 332. Deionized water may be provided from the deionized water source 342 to flush out the manifold 332 in addition to, or in place of non-reactive gas. Electrolyte from the electrolyte sources 304 may also be utilized as a purge medium.

[0047] A second delivery line 352 is teed between the first gas delivery line 350 and the dosing pump 312. A purge fluid includes at least one of the electrolyte, deionized water or non-reactive gas from their respective sources 304, 342, 344 may be diverted from the first delivery line 350 through the second gas delivery line 352 to the dosing pump 312. The purge fluid is driven through the dosing pump 312 and out the output line 340 to the manifold 332. The valve bank 334 typically directs the purge fluid out a drain port 338 to the reclaimation system 232. The various other valves, regulators and other flow control devices for not been described and/or shown for the sake of brevity.

[0048] In one embodiment of the invention, a first chemistry may be provided to the manifold 332 that promotes feature filling of copper on a semiconductor substrate. The first chemistry may include between about 30 and about 65 g/l of copper, between about 55 and about 85 ppm of chlorine, between about 20 and about 40 g/l of acid, between about 4 and about 7.5 ml/L of accelerator, between about 1 and 5 ml/L of suppressor, and no leveler. The first chemistry is delivered from the manifold 332 to a first plating cell 102 to enable features disposed on the substrate to be substantially filled with metal. As the first chemistry generally does not completely fill the feature and has an inherently slow deposition rate, the first chemistry may be optimized to enhance the gap fill performance and the defect ratio of the deposited layer. A second chemistry makeup with a different chemistry from the first chemistry may be provided to another plating cell on system 100 via manifold 332, wherein the second chemistry is configured to promote planar bulk deposition of copper on a substrate. The second chemistry may include between about 35 and about 60 g/l of copper, between about 60 and about 80 ppm of chlorine, between about 20 and about 40 g/l of acid, between about 4 and about 7.5 ml/L of accelerator, between about 1 and about 4 ml/L of suppressor, and between about 6 and about 10 ml/L of leveler, for example. The second chemistry is delivered from the manifold 332 to the second process cell to enable an efficient bulk metal deposition process to be performed over the metal deposited during the feature fill and planarization deposition step to fill the remaining portion of the feature. Since the second chemistry generally fills the upper portion of the features, the second chemistry may be optimized to enhance the planarization of the deposited material without substantially impacting substrate throughput. Thus, the two step, different chemistry deposition process allows for both rapid deposition and good planarity of deposited films to be realized.

[0049] When utilized with a process cell requiring anolyte solutions such as the process cell 200 of FIG. 2B, the plating solution delivery system 111 generally includes an anolyte fluid circuit 380 that is coupled to the inlet 209 of the plating cell 200. The anolyte fluid circuit 380 may include a plurality of additive sources 382 coupled by a dosing pump 384 to a manifold 386 that directs additives (typically not utilized) selectively metered from one or more of the sources 382 and combined with an anolyte in the manifold 386 to those process cells (such as the cell 200) requiring anolyte solution during the plating process. The anolyte may be provided by an anolyte source 388.

[0050]FIG. 4 depicts one embodiment of a process cell 400 configured to remove deposited material from an edge of a substrate 402. The process cell 400 includes a housing 404 having a substrate chuck 406 disposed therein. The substrate chuck 406 includes a plurality of arms, shown as 408A-C, extending from a central hub 410. Each arm 408A-C includes a substrate clamp 412 disposed at a distal end of the arm. The hub 410 is coupled by a shaft 414 to a motor 416 disposed outside of the housing 404. The motor 416 is adapted to rotate the chuck 406 and substrate 402 disposed thereon during processing. During processing, the substrate 402 is rotated while an etchant is delivered from an etchant source 418 to the substrate's edge. The etchant is typically delivered to the substrate's edge through a plurality of upper nozzles 420 positioned within the housing 404 in an orientation that directs the etchant flowing therefrom in a radially outward direction against the substrate's surface. The process cell 400 may also include a plurality of lower nozzles 422 coupled to the etchant source 418 and adapted to direct etchant to the substrate's edge on the side of the substrate opposite the upper nozzle 420. The etchant is typically delivered to the substrate 402 while the substrate rotates between about 100 to about 1,000 rpm. The nozzles 420, 422 are typically configured to direct the etchant at the substrate in a substantially tangential direction, typically with an angle of about 10 to about 70 degrees, or alternatively, between about 10 and about 30 degrees, wherein the angle is defined as being between the substrate surface and the direction or longitudinal axis of the fluid flow or dispensing nozzle. In one embodiment, the etchant is a combination of an acid and oxidizer, such as sulfuric acid, nitric acid, citric acid, or phosphoric acid combined with hydrogen peroxide, which removes deposited copper from the exclusion zone of the substrate (generally the outer annulus of the substrate surface, which is generally about 2 mm or 3 mm wide.

[0051] After the deposited material has been removed from the substrate's edge, deionized water or other cleaning agent is provided through the nozzles 420, 422 to clean the substrate's surface. The substrate 402 is typically rotated at approximately 200 rpm to remove etchant, deionized water and other impurities from the respective upper and lower surfaces of the substrate 402. The various fluids dispended during processing are drained from the housing 404 through a port 424 formed in the bottom of the housing 404. Two process cells configured to remove deposited material from the edge of the substrate which may be adapted to benefit from the invention are described in U.S. patent application Ser. No. 09/350,212, filed Jul. 9, 1999, and U.S. patent application Ser. No. 09/614,406, filed Jul. 12, 2000, both of which are hereby incorporated by reference in their entireties.

[0052]FIG. 5 is a partial sectional view of a process cell 500 configured to spin, rinse and dry a substrate 502 after processing. The process cell 500 includes a housing 504 having a substrate chuck 506 disposed therein. The substrate chuck 506 includes a plurality of arms, shown as 508A-C, extending from a central hub 510. Each arm 508A-C includes a substrate clamp 512 disposed at a distal end of the arm. The hub 512 is coupled by a shaft 514 to a motor 516 disposed outside of the housing 504. The motor 516 is adapted to rotate the chuck 506 and substrate 502 disposed thereon during processing. During processing, the substrate is rotated while a cleaning agent, such as deionized water or alcohol, is delivered from a fluid source 518 to the upper side of the substrate 502 from a plurality of upper nozzles 520 positioned within the housing 504 above the chuck 506. The backside of the substrate 502 is treated with at least one of a cleaning agent or a dissolving agent dispensed from a plurality of lower nozzles 522 disposed below the chuck 506 and coupled to the fluid source 518. Examples of dissolving agents include hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid among others. The fluids are typically delivered to the substrate while the substrate rotates between about 4 to about 4,000 rpm. After the deposited material has been removed from the substrate's edge, the ionized water or other cleaning agent is provided through the nozzles 520, 522 to clean the substrate's surface. The substrate 502 is typically rotated at approximately 100 to about 5000 rpm to dry the substrate while removing liquids and other impurities from the respective upper and lower surfaces of the substrate 502. The various fluids dispended during processing are drained from the housing 504 through a port 524 formed in the bottom of the housing 504. One process cell configured to clean and dry the substrate which may be adapted to benefit from the invention is described in U.S. Pat. No. 6,290,865, issued Sep. 18, 2001, which is hereby incorporated by reference in its entirety.

[0053] In operation, embodiments of the invention generally provide a plating system having multiple plating cells on a single integrated platform, wherein a fluid delivery system for the plating system is capable of providing multiple chemistries to the plating cells. More particularly, for example, assuming that four individual plating cells are positioned on a common system platform, then the fluid delivery system of the invention is capable of providing a different chemistry to each of the four plating cells. The different chemistries may include different base solutions or virgin makeup solutions, and further, may include various additives at various concentrations, including absence of selected additives.

[0054] Multiple chemistry capability for a single platform has advantages in several areas of semiconductor processing. For example, the ability to provide multiple chemistries to multiple plating cells on a unitary platform allows for a single plating system take advantage of positive characteristics of multiple chemistries in a single platform on a single substrate. Multiple chemistry capability has application, for example, to feature fill and bulk fill process, as a first plating solution or chemistry may be tailored to a feature full process (low defect, but slow deposition rate process), while a second solution may be tailored to a feature bulk fill process (a more rapid deposition process that may be implemented once the feature is primarily filled by the first process). Additionally, a multiple chemistry plating system would facilitate plating directly on barrier layers, as a first plating chemistry could be used to facilitate adhesion of a first material to the barrier layer, and then a second chemistry could be used plate a second material over the first material layer on top of the barrier layer and fill the features without encountering barrier layer plating adhesion challenges. Further, a multiple chemistry system would also be beneficial to an alloy plating process, wherein a first chemistry could be used to plate the alloy layer and then a second chemistry could be used to plate a different layer or another alloy layer over the previously deposited layer. Further still, a multiple chemistry process could be used to substantially improve defect ratios in semiconductor substrate plating processes via utilization of a first chemistry configured to plate a first layer with minimal defects, and then a second chemistry configured to plate a second layer over the first layer with minimal defects in manner that optimizes throughput.

[0055] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Referenced by
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US7473339 *Apr 16, 2004Jan 6, 2009Applied Materials, Inc.Slim cell platform plumbing
US7628898Aug 5, 2005Dec 8, 2009Semitool, Inc.Method and system for idle state operation
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US8236159Apr 28, 2006Aug 7, 2012Applied Materials Inc.Electrolytic process using cation permeable barrier
US8852417Feb 27, 2012Oct 7, 2014Applied Materials, Inc.Electrolytic process using anion permeable barrier
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Classifications
U.S. Classification205/157, 257/E21.175, 257/E21.585
International ClassificationH01L21/00, C25D7/12, H01L21/288, H01L21/768
Cooperative ClassificationH01L21/67167, H01L21/76877, H01L21/67011, H01L21/2885, H01L21/6723, C25D7/123, C25D17/001
European ClassificationH01L21/67S2, H01L21/67S2Z2C, H01L21/67S2Z10P, H01L21/288E, H01L21/768C4, C25D7/12
Legal Events
DateCodeEventDescription
May 14, 2003ASAssignment
Owner name: APPLIED MATERIALS, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:YANG, MICHAEL X.;XI, MING;ELLWANGER, RUSSELL C.;AND OTHERS;REEL/FRAME:014082/0729;SIGNING DATES FROM 20030429 TO 20030508