Electrodeposition system using ion exchange membrane cleaning method

Abstract

[0003] Examples related to cleaning an ion exchange membrane in an electrodeposition system are disclosed. In one example, the electrodeposition system includes a fluid distribution system comprising a membrane assembly including a membrane frame configured to support an ion exchange membrane defining a boundary of a cathode chamber. The fluid distribution system further includes a high resistance virtual anode (HRVA) positioned between the membrane frame and a substrate holder, a catholyte circulation loop operable to flow catholyte in a first direction across a surface of the HRVA facing the substrate holder, and a plurality of flow barriers extending between the membrane frame and the HRVA along a second direction transverse to the first direction. Cleaning conduits are positioned between adjacent flow barriers, and each cleaning conduit is configured to receive catholyte from the catholyte circulation loop and direct the catholyte toward the membrane assembly via a plurality of emitters.

Description

[Background technology]

[0001] Electroplating can be used in integrated circuit manufacturing processes to deposit conductive films on substrates. Electroplating involves electrochemically reducing dissolved ions of a selected metal to their elemental state on a substrate to form a film of the selected metal. The electroplating system includes a cathode chamber through which a catholyte solution circulates and an anode chamber through which an anolyte solution circulates. An ion exchange membrane is located between the cathode and anode chambers. The ion exchange membrane selectively allows some ions to pass from the anolyte to the catholyte while preventing the passage of other ions and organic additives. Summary of the Invention

[0002] This section is provided to introduce a selection of simplified concepts that are further described in the Detailed Description below. This section is not intended to identify key features or essential features of the present subject matter, nor is it intended to be used to limit the scope of the present subject matter. Moreover, the present subject matter is not limited to embodiments that solve any or all of the disadvantages noted anywhere in this disclosure.

[0003] Examples related to actively cleaning an ion exchange membrane in an electrodeposition system are disclosed. In one exemplary system, the electrodeposition system includes a fluid distribution system. The fluid distribution system includes a membrane assembly including a membrane frame configured to support an ion exchange membrane defining a boundary of a cathode chamber. The fluid distribution system further includes a high resistance virtual anode (HRVA) positioned between the membrane frame and a substrate holder, a catholyte circulation loop operable to flow catholyte in a first direction across a surface of the HRVA facing the substrate holder, and a plurality of flow barriers extending between the membrane frame and the HRVA along a second direction transverse to the first direction. Cleaning conduits are positioned between adjacent flow barriers. Each cleaning conduit is configured to receive catholyte from the catholyte circulation loop and direct the catholyte toward the membrane assembly via a plurality of emitters.

[0004] In some such instances, the flow barrier is alternatively or additionally integrated with the membrane frame.

[0005] In some such examples, adjacent flow barriers optionally or additionally define opposite walls of the divided volumes, and the flow barriers optionally or additionally include openings proximal to the membrane frame, the openings fluidly connecting the adjacent divided volumes.

[0006] In some such instances, the wash conduit is alternatively or additionally formed in a distribution manifold that is fluidly connected to the catholyte circulation loop.

[0007] In some such instances, the distribution manifold is alternatively or additionally fluidly connected to the catholyte circulation loop through an inlet manifold in the membrane frame.

[0008] In some such instances, the distribution manifold is alternatively or additionally fluidly connected to the inlet manifold of the membrane frame via two or more inlets.

[0009] In some such examples, the distribution manifold alternatively or additionally comprises one or more outlets opposite the two or more inlets.

[0010] In some such examples, the membrane frame alternatively or additionally comprises a grid structure that includes a plurality of openings that expose the ion exchange membrane.

[0011] In some such instances, the emitters are alternatively or additionally positioned to diffuse catholyte toward the intersections of the grid structure.

[0012] In some such instances, the emitters are alternatively or additionally positioned to diffuse catholyte toward alternating intersections of the grid structure.

[0013] Another embodiment provides a fluid distribution system for an electrodeposition system, the fluid distribution system including a membrane frame configured to support an ion exchange membrane, the membrane frame including a grid structure and a plurality of flow barriers extending from the grid structure, the fluid distribution system further including a plurality of washing conduits, each washing conduit of the plurality of washing conduits positioned between adjacent flow barriers and configured to receive catholyte from the catholyte circulation loop and direct the catholyte toward the membrane assembly via a plurality of emitters.

[0014] In some such instances, the flow barrier is alternatively or additionally integrated with the membrane frame.

[0015] In some such instances, the wash conduits are alternatively or additionally formed in a distribution manifold that is fluidly connected to the inlet manifold of the membrane frame via two or more inlets.

[0016] In some such examples, the distribution manifold alternatively or additionally comprises one or more outlets opposite the two or more inlets.

[0017] In some such examples, the grid structure alternatively or additionally comprises a plurality of openings exposing the ion exchange membrane, and the emitters are positioned to diffuse catholyte toward the intersections of the grid structure.

[0018] In some such instances, the emitters are alternatively or additionally positioned to diffuse catholyte toward alternating intersections of the grid structure.

[0019] Another embodiment provides a method for cleaning an ion exchange membrane in an electrodeposition system, the method including flowing catholyte in a first direction across an HRVA, the HRVA separated from the ion exchange membrane by a membrane frame, the membrane frame including a plurality of flow barriers extending from the membrane frame to the HRVA in a second direction transverse to the first direction, the method further including diverting some of the catholyte to a distribution manifold including cleaning conduits located between adjacent flow barriers, each cleaning conduit configured to direct the catholyte toward the membrane frame via a plurality of emitters.

[0020] In some such examples, diverting the catholyte to the distribution manifold optionally or additionally includes diverting the catholyte through two or more inlets fluidly connected to the inlet manifold of the membrane frame, and the method optionally or additionally includes diverting the catholyte to one or more outlets located opposite the inlets of the distribution manifold.

[0021] In some such examples, directing the catholyte toward the membrane frame via a plurality of emitters optionally or additionally includes diffusing the catholyte toward the intersections of a grid structure of the membrane frame, the grid structure having a plurality of openings that expose the ion exchange membrane.

[0022] In some such examples, diffusing catholyte toward the intersections of the grid structure alternatively or additionally includes diffusing catholyte toward alternating intersections of the grid structure. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a block diagram of an exemplary electrodeposition tool.

[0024] [Figure 2] FIG. 2 is a schematic diagram of an exemplary electrodeposition chamber including a fluid distribution system.

[0025] [Figure 3]FIG. 3 illustrates an exemplary fluid distribution system for an electrodeposition chamber.

[0026] [Figure 4] FIG. 4 illustrates an exemplary membrane assembly for an electrodeposition chamber with a fluid distribution system.

[0027] [Figure 5] FIG. 5 is an exemplary distribution manifold and gasket for the membrane assembly of FIG.

[0028] [Figure 6A] FIG. 6A illustrates an exemplary structure of a distribution manifold gasket assembly. [Figure 6B] FIG. 6B illustrates an exemplary configuration of a distribution manifold gasket assembly.

[0029] [Figure 7] FIG. 7 is a schematic diagram of an exemplary flow focusing manifold for a membrane assembly.

[0030] [Figure 8] FIG. 8 is a schematic diagram of an exemplary cleaning method for a flow focusing manifold using a distribution manifold.

[0031] [Figure 9] FIG. 9 is an exemplary graph of the inlet pressure in a flow focusing membrane assembly.

[0032] [Figure 10] FIG. 10 is a flow diagram illustrating an exemplary method for cleaning an ion exchange membrane in an electrodeposition system. DETAILED DESCRIPTION OF THE INVENTION

[0033] The term "anode" may generally refer to the conductive structure where the electrochemical oxidation reaction occurs during the electroplating process.

[0034] The term "anode compartment" may generally refer to a physical structure configured to hold at least an anode and an anolyte, and providing selective isolation from the cathode compartment.

[0035] The term "anolyte" may generally refer to the solution used in the anode chamber during the electroplating process.

[0036] The term "opening" may generally refer to an opening that allows solution to flow between adjacent volumes.

[0037] The term "cathode" may refer to a conductive layer on a substrate that grows during electroplating, generally by the electrochemical reduction of ions.

[0038] The term "cathode compartment" may generally refer to a physical structure configured to hold at least a cathode and catholyte, and providing selective isolation from the anode compartment.

[0039] The term "catholyte" may generally refer to the solution used in the cathode chamber during the electroplating process.

[0040] The term "circulation loop" may generally refer to a path through which a liquid is recirculated over time. The term circulation loop may generally refer to a catholyte circulation loop or may generally refer to an anolyte circulation loop.

[0041] The term "distribution manifold" may generally refer to a structure that allows a liquid to be diverted from one conduit to multiple conduits.

[0042] The terms "electroplating," "plating," "deposition," and derivatives thereof may generally refer to a process in which dissolved ions of one or more metals are reduced onto a substrate surface to form a film of one or more metals.

[0043] The term "electrodeposition system" may generally refer to a machine configured to perform electrodeposition.

[0044] The term "emitter" may generally refer to a structure that directs the flow of solution out of a conduit.

[0045] The term "flow barrier" may generally refer to a structure that impedes the flow of a liquid or solution in a predetermined direction.

[0046] The term "fluid distribution system" may generally refer to a series of conduits, pipes, manifolds, pumps, inlets, and outlets configured to distribute fluids for an electrodeposition system.

[0047] The term "grid structure" may generally refer to an arrangement of structures that intersect at intersections to form a two-dimensional mesh with openings between the component structures.

[0048] The term "high resistance virtual anode" (HRVA) may refer to an ion-resistant structure generally located between the substrate holder and the anode of an electroplating tool through which ions flow from the anode to the cathode during electroplating. The HRVA resembles a fairly stable and uniform source of current in close proximity to the cathode.

[0049] The term "inlet manifold" may generally refer to a set of chambers or conduits that take in fluid from a fluid source and distribute the fluid to one or more locations.

[0050] The term "inlet" may generally refer to a structure that serves as an entrance through which fluid enters a flow path.

[0051] The term "grid structure intersection" may generally refer to a point or area where component structures of the grid structure meet at an angle.

[0052] The term "ion exchange membrane" may generally refer to a semipermeable membrane that allows the transport of certain dissolved ions, but not other dissolved ions or charge-neutral molecules.

[0053] The term "wash conduit" may generally refer to a set of tubes configured to receive catholyte at an inlet and diffuse the catholyte towards an ion exchange membrane through one or more emitters.

[0054] The term "membrane assembly" may generally refer to a set of components including at least an ion exchange membrane, a membrane frame, and a portion of the catholyte circulation loop.

[0055] The term "membrane frame" may generally refer to a device that supports an ion exchange membrane.

[0056] The term "outlet" may generally refer to a structure that serves as an outlet for fluid to exit a flow path.

[0057] The term "divided volume" may generally refer to the volume between the flow barriers.

[0058] The term "substrate" refers to any object onto which a film can be deposited.

[0059] The term "substrate holder" may generally refer to any structure for supporting a substrate during an electrodeposition process.

[0060] There is an increasing demand in the semiconductor processing industry for rapid electrodeposition of metals onto substrates while maintaining high uniformity. To meet this demand, electrodeposition technology is moving toward higher plating currents, lower plating bath temperatures, and chemistries that can support higher plating rates. For example, catholyte and anolyte solutions may contain near-saturation concentrations of metal salts. However, such conditions can result in the buildup of metal salt deposits that form on electroplating tools over time.

[0061] As a more specific example, to achieve a relatively high copper electroplating growth rate, the plating current may exceed 10 amperes. Furthermore, the catholyte and anolyte may contain nearly saturated solutions of copper sulfate (CuSO), sulfuric acid (HSO), and other possible supporting additives. Copper electroplating may use a cation exchange membrane to separate the anode and cathode compartments to prevent oxidation of organic additives at the anode. An exemplary cation exchange membrane may include a sulfonated tetrafluoroethylene-based fluorinated polymer-copolymer. Metal ions that permeate the cation exchange membrane from the anolyte to the catholyte add to the metal ion concentration in the catholyte adjacent to the cation exchange membrane. This local increase in concentration may result in supersaturation of the catholyte solution at the cation exchange membrane under some conditions. Supersaturation may be particularly problematic when the catholyte stagnates at the membrane surface. This can lead to the formation of metal salt deposits on the cation exchange membrane and / or adjacent structures. The low convection of the catholyte in this membrane may result in the formation of precipitates and crystal growth. The deposition of precipitates will passivate portions of the cation exchange membrane over time, which will adversely affect the uniformity of the electroplated film on the substrate.

[0062] Currently, manual methods are used to restore the target substrate profile of tools plagued by deposit buildup. Manual intervention would involve removal / replacement of the affected film and parts. Such intervention would be time-consuming and relatively expensive, at least in terms of the cost of the parts and the impact on tool uptime. Other methods, such as reducing the metal ion concentration and / or current used in electroplating, could reduce the tool's usability. Plating bath temperature could be increased, but this would require the introduction of additives. Such additives could affect the plating process.

[0063] Accordingly, embodiments are disclosed relating to cleaning ion exchange membranes to reduce catholyte stagnation at the membrane. Reducing catholyte stagnation may help reduce metal salt deposit buildup. The disclosed embodiments increase flow at the ion exchange membrane using a fluid distribution system. Additionally, the disclosed embodiments can focus flow directly at the membrane itself. The disclosed embodiments may help avoid part replacement due to deposit buildup, thereby reducing the overall impact of deposit removal on tool uptime. Furthermore, reduced buildup may result in more even and uniform plating over time. The disclosed embodiments are primarily described in terms of copper sulfate crystal buildup on copper electrodeposition tools and ion exchange membranes. However, the disclosed embodiments may use any suitable chemicals in any suitable electrodeposition tool. The disclosed process is non-invasive. Thus, the disclosed process can be performed without disrupting the surface of the electrodeposition tool.

[0064] For example, a membrane frame configured to support an ion exchange membrane may be configured to divert some of the catholyte solution into a distribution manifold that directs the flow across the surface of the ion exchange membrane. This flow helps reduce the risk of stagnant flow, especially near the corners and outlet areas of the membrane frame. This flow may therefore help prevent crystal formation.

[0065] FIG. 1 illustrates a schematic block diagram of an exemplary electrodeposition tool 100. The electrodeposition tool 100 includes an electrodeposition chamber 102 including an anode chamber 104 and a cathode chamber 106. The electrodeposition tool 100 further includes an ion exchange membrane 108 separating the anode chamber 104 and the cathode chamber 106, and an HRVA 109 within the cathode chamber 106. The anode chamber 104 includes an anode 110. The anode chamber 104 further includes an anolyte. The cathode chamber 106 includes a catholyte. The catholyte includes ionic species that deposit as a metal on a cathode layer of a substrate 111 by electrochemical reduction. In some embodiments, the anode 110 may include a soluble anode formed from the deposited metal. In other embodiments, the anode 110 may include an insoluble anode. If the anode 110 contains a deposited metal, electrochemical oxidation of the anode 110 at least partially replenishes ionic species consumed by the electroplating process. Bulk anolyte and / or catholyte may be added from time to time to replenish the ionic species.

[0066] The ion exchange membrane 108 allows selected ions to pass from the anode chamber 104 to the cathode chamber 106 while preventing organic species and some ionic species from crossing between the cathode chamber 106 and the anode chamber 104. As an example, the ion exchange membrane 108 may allow metal ions to pass from the anode chamber 104 to the cathode chamber 106 for plating. As described above, the HRVA 109 comprises an ion-resistant element that resembles a source of fairly stable, uniform current in close proximity to the substrate cathode.

[0067] The substrate holder 112 is connected to a substrate holder movement system 113 that includes a lift 114 configured to adjust the space between the substrate holder 112 and the HRVA 109. For example, the lift 114 can lower the substrate holder 112 to position the substrate 111 in the catholyte for electroplating. The lift 114 can also raise the substrate holder 112 from the catholyte after electroplating. The substrate holder movement system 113 can also include components for controlling the opening and closing of the substrate holder 112.

[0068] Catholyte may be circulated between the cathode chamber 106 and the catholyte reservoir 120 by a combination of gravity and one or more pumps 122. Similarly, anolyte may be circulated through the anolyte reservoir 124 and the anode chamber 104 by a combination of gravity and one or more pumps 126.

[0069] 2 schematically illustrates an exemplary electrodeposition system 200 including an electroplating chamber 202. The electroplating chamber 202 is an example of the electrodeposition chamber 102 of FIG. 1. The electroplating chamber 202 includes an anode chamber 204 and a cathode chamber 206. The electroplating chamber 202 further includes a cation exchange membrane 208 that defines a boundary between the anode chamber 204 and the cathode chamber 206. The cation exchange membrane 208 is an example of the ion exchange membrane 108. The substrate holder 210 is configured to hold and position the substrate 212 such that a deposition surface of the substrate 212 is located within the cathode chamber 206.

[0070] The anode compartment 204 includes an anolyte reservoir 216 in which an anode 218 is disposed. In this embodiment, the anode 218 comprises a copper metal anode. In other embodiments, the anode 218 may comprise another soluble or insoluble anode. A voltage source 219 applies a voltage across the substrate 212 and the anode 218 to drive a flow of metal ions for deposition onto the substrate 212.

[0071] The anolyte tank 216 is disposed within an anolyte circulation loop 220. The anolyte enters the anode chamber at an inlet 222 and exits the anode chamber at an outlet 224. The anolyte circulation loop 220 includes a heater 226 (e.g., a heater / chiller) configured to adjust and / or maintain the temperature of the anolyte flowing through the anolyte circulation loop 220. The electroplating chamber 202 further includes a fluid distribution system 230. The fluid distribution system 230 includes a membrane assembly 232 including a membrane frame 234 configured to support the ion exchange membrane 208. The fluid distribution system 230 further includes a HRVA 236 located between the membrane frame 234 and the substrate holder 210.

[0072] The fluid distribution system 230 is configured to deliver copper ions (Cu) deposited on the substrate 212, which acts as a cathode. 2+ ) is supplied to the cathode chamber 206. The catholyte reservoir 238 is disposed within a catholyte circulation loop 240. The catholyte enters the cathode chamber 206 at an inlet 242 and exits the cathode chamber 206 at an outlet 244. The catholyte circulation loop 240 includes a heater 246 (e.g., a heater / chiller) configured to regulate and / or maintain the temperature of the catholyte flowing through the catholyte circulation loop 240.

[0073] In some embodiments, for copper electroplating, the anode 218 may comprise, for example, a copper piece (e.g., a sphere) or a copper plate. As noted above, in other embodiments, the anode 218 may comprise an insoluble anode. In the illustrated embodiment, the applied voltage causes the anode 218 to melt copper metal, Cu. 2+ The cation exchange membrane 208 is 2+ is passed from the anolyte reservoir 216 to the catholyte reservoir 238. 2+ The ions replace at least some of the copper ions in the catholyte reservoir 238 that are reduced onto the substrate 212 .

[0074] The heater 246 may be controlled to maintain the catholyte bath 238 at a predetermined process temperature during the electroplating process. The heater 226 may similarly be controlled to maintain the anolyte bath 216 at a predetermined process temperature during the electroplating process. The process temperature may include relatively low temperatures in some processes. For example, some copper deposition processes may use process temperatures in the range of 22-26°C.

[0075] As noted above, some electroplating conditions may increase the concentration of dissolved copper ions in the catholyte near the cation exchange membrane surface. The resulting concentration can exceed the solubility limit of the catholyte solvent (e.g., water) at the process temperature. This leads to the formation of crystals in the cation exchange membrane. In the example of FIG. 2, Cu in the anolyte reservoir 216 2+ The ions pass through the cation exchange membrane 208 to the catholyte reservoir 238. Thus, the catholyte directly above the cation exchange membrane 208 contains the catholyte in the catholyte reservoir 238 and additional Cu from the anolyte reservoir 216. 2+ Contains ions from both Cu and Cu. 2+ The concentration increases as the plating current increases.

[0076] Excess Cu 2+ Without sufficient convection of the catholyte to remove ions, the solution above the cation exchange membrane can precipitate solid copper salts on the membrane. CuSO4 will be the primary component of the copper salt precipitate. Copper-containing catholytes may contain chloride and sulfonate anions. These anions can also form copper deposits. Metal salt deposits can also occur with other electroplating chemistries. Examples include tin alloys and tin-silver alloys. For tin-silver, exemplary counter anions include methanesulfonic acid and organic acids. Deposition can also occur with other electroplating metals, including cobalt, indium, and nickel.

[0077] The presence of metal salt deposits on the cation exchange membrane 208 can interfere with fluid transport and current distribution. This condition may be referred to as passivation. If an area of ​​the cation exchange membrane becomes partially or completely passivated, uneven current distribution will occur. This can cause uneven plating of metal on the substrate. In some embodiments, one or more sensors may be installed in and around the electroplating chamber 202 to monitor conditions and provide an indication of non-uniformity indicative of metal salt deposit buildup. Exemplary sensors include a cathodic current sensor array and / or one or more optical sensors.

[0078] Passive cleaning may not be sufficient to reduce catholyte stagnation at the cation exchange membrane 208. Thus, the disclosed embodiments use an active cleaning system to avoid stagnation and the resulting risk of metal salt deposit formation.

[0079] The catholyte circulation loop 240 is operable to flow catholyte in a first direction across the surface of the HRVA 236. This direction is indicated by the arrow between the inlet 242 and the outlet 244. As an example, some of the catholyte travels through channels in the membrane frame 234 and reaches inlet holes in the plates supporting the HRVA 236. This would be referred to as an underflow HRVA. One or more outlet holes in such plates may then couple the catholyte back to the opposite catholyte circulation loop 240 via the outlet 244.

[0080] In this embodiment, the plurality of flow barriers 248 extend between the membrane frame 234 and the HRVA 236 along a second direction transverse to the first direction. This configuration may be referred to as a flow focusing manifold. The flow barriers 248 may prevent flow from flowing under the HRVA 236. This may reduce the fluid pressure required to flow catholyte across the HRVA 236. This may help maintain or improve plating performance on the substrate 212.

[0081] Additionally, the membrane frame 234 includes an inlet manifold 250 for receiving and distributing catholyte from the catholyte circulation loop 240. Some of the received catholyte may be directed throughout the HRVA 236 as described above. At least some of the received catholyte may be diverted to a plurality of wash conduits 252 located between adjacent flow barriers 248.

[0082] The cleaning conduits 252 are shown positioned between adjacent flow barriers 248. Each cleaning conduit 252 may be configured to receive catholyte from the catholyte circulation loop 240 and direct the catholyte toward the membrane assembly via a plurality of emitters (e.g., as indicated by the arrows). The cleaning conduits 252 thus provide a directed flow of catholyte toward the cation exchange membrane 208, thereby cleaning the substrate-facing surface of the cation exchange membrane 208.

[0083] 3 shows a cross section of an exemplary membrane assembly 300. The membrane assembly 300 may be an example of the membrane assembly 232. The membrane assembly 300 includes a membrane frame 302, an ion exchange membrane 304, and an HRVA 306. The HRVA 306 may be attached to a surface (e.g., the upper surface) of the membrane frame 302. The ion exchange membrane 304 may be fixed or attached to the membrane frame 302 on the opposite side (e.g., the lower surface) from the HRVA 306. In this example, the membrane frame 302 includes a grid structure including a plurality of gap openings 308 through which the ion exchange membrane 304 is exposed to the fluid on both sides.

[0084] The flow barrier 310 is integral with the membrane frame 302. The flow barrier 310 extends transversely to the direction of fluid flow across the HRVA 306. The flow barrier 310 extends across the membrane frame 302. In this embodiment, the flow barrier 310 is integrally formed with a portion of a grid structure. For example, every other cross bar of the grid may extend from the membrane frame 302 toward the HRVA 306 to prevent catholyte flow from flowing underneath the HRVA 306. In some embodiments, a gasket is located between the flow barrier 310 and the HRVA 306.

[0085] Thus, adjacent flow barriers 310 define opposite walls of a divided volume 312. The flow barrier 310 includes an opening 314 proximal to the membrane frame 302. The term "proximal to the membrane frame" may generally refer to a location closer to the ion exchange membrane 304 than the HRVA 306 when the membrane assembly 300 is assembled. The opening 314 fluidly connects adjacent divided volumes 312. The opening 314 allows some catholyte to cross the flow barrier 310 from a higher pressure (e.g., inlet) to a lower pressure (e.g., outlet) and thereby flow between adjacent divided volumes 312, thereby enhancing cleaning of the ion exchange membrane 304.

[0086] A cleaning conduit 316 extends through the center of each divided volume 312 and operates to diffuse catholyte to clean the lower exposed opening 308 of the ion exchange membrane 304. The cleaning conduit 316 may be constructed of a non-conductive material, such as a polymer or ceramic, to reduce electric fields that may interfere with the electrodeposition process.

[0087] Each cleaning conduit 316 includes a plurality of emitters 318. In some embodiments, the emitters 318 direct the catholyte toward a grid structure of the membrane frame 302. For example, the emitters 318 may be designed to emit the catholyte toward the intersections of the grid structure. However, other configurations are contemplated. In some embodiments, the emitters 318 direct the catholyte flow perpendicular to the surface of the respective cleaning conduit. However, some or all of the emitters may have directional outputs, such as nozzles. This may allow for strategic placement of the emitters 318, adjustable emission direction, and / or targeted emission to areas where crystal growth may develop.

[0088] 4 shows a cutaway exploded view of an exemplary membrane assembly 400 for an electrodeposition chamber with a fluid distribution system. The membrane assembly 400 may be an example of the membrane assemblies 232 and 300. The membrane assembly 400 includes a membrane frame 402 configured to support an ion exchange membrane 404. The membrane frame 402 includes a plurality of flow barriers 406 and an inlet manifold 408 configured to receive catholyte from the catholyte circulation loop.

[0089] The distribution manifold 410 is configured to connect to the membrane frame 402 via an external channel 411 for cleaning. The distribution manifold 410 comprises a plurality of cleaning conduits 412, each of which contains several emitters 414. The distribution manifold 410 may be fluidly connected to the catholyte circulation loop via an inlet manifold 408. In some embodiments, the membrane frame 402 may be positioned to accommodate the fluid inlet of the distribution manifold 410.

[0090] When in place, the distribution manifold 410 may be fluidly connected to the inlet manifold 408 of the membrane frame 402 via two or more inlets. In this example, three inlets 415, 416, and 417 are shown positioned around the periphery of the membrane frame 402. The inlets 415, 416, and 417 extend from the inlet manifold 408 to the distribution manifold 410 and deliver catholyte to the distribution manifold 410.

[0091] In some embodiments, additional inlets may be included, some or all of which may be connectable with plugs (e.g., threaded or press-fit plugs). In this manner, the fluid pressure profile of the membrane assembly 400 can be adjusted. Such adjustments may be performed dynamically by controllable valves during maintenance or installation. For example, different plating applications may call for different flow rates through the catholyte circulation loop. The positioning of different substrates relative to the HRVA will similarly affect the flow and pressure through the distribution manifold 410.

[0092] In some embodiments, the manifold allows for approximately equal flow output from each emitter in the cleaning conduit 412, including the emitter located furthest from the inlet. The size of the emitters, relative to the size of the flow passage for a given flow rate, allows for a reasonably low pressure drop between the inlet and the far end of the manifold. This constant pressure results in a steady flow through the emitters.

[0093] An electrical shield (not shown) may be attached to the outer groove 411. The thickness of such an electrical shield will affect plating on the substrate. By using a thin distribution manifold (discussed further with respect to FIG. 6B), the backside insert can be relatively thick. In such a configuration, it would be advantageous to have a large inlet flow rate. The three inlets shown can provide a suitable flow rate.

[0094] Figure 5 shows an exploded view 500 of a distribution manifold 410 and associated gasket 510 for the membrane assembly of Figure 4. Distribution manifold 410 includes an HRVA-facing portion 515 and a membrane-facing portion 517. Distribution manifold 410 is shown to include a pair of outlets 522 and 523 opposite inlets 415, 416, and 417. Outlets 522 and 523 may include circular openings, as shown, and / or elliptical openings, such as arcs of a circle extending around the length of the distribution manifold.

[0095] In this embodiment, the outlets 522 and 523 are positioned in the membrane facing portion 517 and the gasket 510. The emitters 525 are arranged along the cross member of the membrane facing portion 517.

[0096] Gasket 510 may be used to create a seal when attaching distribution manifold 410 to membrane frame 402. The gasket is shown with a similar footprint as distribution manifold 410, but seals inlets 415, 416, and 417, and outlets 522 and 523. Thus, gasket 510 may have a different shape than other embodiments while accommodating these ports. Gasket 510 may be made of an elastomeric material. Additionally, gasket 520 may be bonded to membrane facing portion 517.

[0097] 6A and 6B show two example configurations of a distribution manifold gasket assembly. In various embodiments, the distribution manifold 410 may be positioned or 3D printed as a single piece or as an assembly of interlocking parts. In these embodiments, two pieces with similar footprints are stacked and bonded to form the distribution manifold. For example, an HRVA-facing portion and a membrane-facing portion are positioned and then solvent bonded.

[0098] Distribution manifold gasket assembly 600 includes an HRVA-facing portion 602, a membrane-facing portion 604, and a gasket 606. An inlet 608 is shown in gasket 606. HRVA-facing portion 602 and a portion of membrane-facing portion 604 create a cleaning conduit 610 having an emitter 612 formed in membrane-facing portion 604. In this example, HRVA-facing portion 602 and membrane-facing portion 604 both have depths and may be positioned to form a relatively thick structure for the distribution manifold.

[0099] Distribution manifold gasket assembly 620 includes an HRVA-facing portion 622, a membrane-facing portion 624, and a gasket 626. An inlet 628 is shown in gasket 626. HRVA-facing portion 622 and a portion of membrane-facing portion 624 create a cleaning conduit 630 having an emitter 632 formed in membrane-facing portion 624. In this embodiment, membrane-facing portion 624 is shallow, with openings positioned for the emitter, inlet, and outlet.

[0100] 7 and 8 show an exemplary membrane frame 700. The membrane frame 700 comprises a grid structure 702 that includes a plurality of openings 704 that expose the underlying cation exchange membrane. As such, the membrane frame 700 may be an example of the membrane frame 300.

[0101] The membrane frame 700 includes a plurality of flow barriers 706 extending from separate grid lines transverse to the catholyte flow across the HRVA, as indicated by the arrows. The grid structure accommodates the positioning of the flow barriers to help avoid impeding conductivity through the cation exchange membrane. The membrane frame 700 includes an inlet 708. The inlet 708 receives catholyte from the catholyte circulation loop. The membrane frame 700 further includes an outlet 710. The outlet 710 directs the catholyte back into the cathode circulation loop.

[0102] As shown in Figure 3, the cleaning conduits of the distribution manifold may be positioned in the partitioned volume between adjacent flow barriers. This is shown schematically at 800 in Figure 8. Cleaning conduits 802, 804, and 806 alternate with the flow barriers 706. Each cleaning conduit includes a plurality of emitters 810, shown as circles. In some embodiments, the emission is directed to adjacent portions of the grid structure 702, thereby agitating the nearby catholyte without directing flow directly at the ion exchange membrane.

[0103] The emitters 810 are positioned to emit catholyte toward the intersections of the grid structure 702. In this embodiment, the emitters are positioned to emit catholyte toward alternating intersections of the grid structure. In this manner, the cleaning conduits create a generally uniform catholyte distribution across the membrane frame 700 between the flow barriers 706.

[0104] As shown at 820, the emitters 810 emit catholyte as fluid jets that strike the intersections 822 of the grid structure 702, resulting in distribution of the escaping catholyte to adjacent openings 704. The flow barriers 706 create partitioned volumes within the membrane assembly, so that fluid emitted from one emitter 810 does not affect membrane cleaning in an adjacent partitioned volume. The distribution manifold may be comprised of multiple conduits, one or more conduits per partitioned volume, so that each partitioned volume is cleaned. This ensures proper uniform cleaning across the membrane surface.

[0105] 9 shows exemplary graphs depicting inlet pressure (e.g., pounds per square inch) over a range of plating pump total flow rates (e.g., liters per minute) for different plating gap distances. Graph 900 shows the inlet pressure when the distribution manifold is not engaged, and graph 910 shows the inlet pressure when the distribution manifold is engaged. Each graph shows pressure versus flow for a range of increasing distances from a reference position (+1.5, +2.5, and +3.5 arbitrary units from reference) for the plating gap (e.g., between the top of the HRVA and the bottom of the substrate) when the substrate is not engaged (e.g., no plate).

[0106] For all plating gaps, the inlet pressure trends are similar whether the distribution manifold is engaged (graph 910) or not (graph 900). Therefore, the system with the distribution manifold engaged performs similarly to the model without the distribution manifold for electrodeposition conditions over a similar pressure range and plating gap range.

[0107] Such flow rates / pressures can also be used to model the pressure of the catholyte being emitted from the manifold emitters. In one example, emitter openings with diameters of approximately 0.025 to 0.05 inches (approximately 0.0635 to 0.127 centimeters) were simulated. At some flow rates, openings with diameters of approximately 0.035 inches (approximately 0.0889 centimeters) allowed for equal flow through each emitter, while larger openings created uneven flow and smaller openings caused choked flow. However, performance can vary depending on the dimensions of the distribution manifold, among other factors.

[0108] 10 shows a flow diagram depicting an exemplary method 1000 for cleaning an ion exchange membrane in an electrodeposition system. Method 1000 may be performed by any suitable electrodeposition system, including a fluid distribution system, such as electrodeposition system 200.

[0109] The method 1000 includes, at 1010, flowing catholyte in a first direction across a high resistance virtual anode (HRVA). The HRVA is separated from the ion exchange membrane by a membrane frame. The membrane frame further comprises a plurality of flow barriers extending from the membrane frame to the HRVA in a second direction transverse to the first direction. The membrane frame may be positioned to receive catholyte from the catholyte circulation loop to an inlet manifold. The membrane frame is further configured to direct the catholyte in the first direction.

[0110] At 1020, method 1000 includes diverting some catholyte to a distribution manifold including flushing conduits positioned between adjacent flow barriers. Each flushing conduit is configured to direct the catholyte toward the membrane frame via a plurality of emitters. In some such embodiments, diverting the catholyte to the distribution manifold includes diverting the catholyte through two or more inlets fluidly connected to an inlet manifold of the membrane frame. In such embodiments, method 1000 further includes diverting the catholyte to one or more outlets of the distribution manifold. The one or more outlets are positioned opposite the inlets. In some such embodiments, directing the catholyte toward the membrane frame via a plurality of emitters includes discharging the catholyte toward intersections of a grid structure of the membrane frame. The grid structure defines a plurality of openings that expose the ion exchange membrane. In some such embodiments, discharging the catholyte toward the intersections of the grid structure includes discharging the catholyte toward alternating intersections of the grid structure, as shown in FIG. 8 .

[0111] It will be understood that the structures and / or techniques described herein are exemplary in nature, as many variations are possible, and that these specific embodiments or examples should not be considered limiting. The specific procedures or methods described herein may represent one or more of any number of process methods. As such, various acts shown and / or described may be performed in the order shown and / or described, in other orders, in parallel, or omitted. Similarly, the order of the processes described above may be changed.

[0112] The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems, and configurations, as well as other features, functions, acts, and / or properties described herein, and all equivalents thereof.

Claims

1. 1. An electrodeposition system comprising: a membrane assembly having a membrane frame configured to support an ion exchange membrane, the ion exchange membrane defining a boundary of a cathode compartment; a high resistance virtual anode (HRVA) located between the film frame and the substrate holder; a catholyte circulation loop operable to flow catholyte in a first direction across a surface of the HRVA opposite the substrate holder; a plurality of flow barriers extending between the membrane frame and the HRVA along a second direction transverse to the first direction; a plurality of flushing conduits located between adjacent flow barriers, each flushing conduit configured to receive catholyte from the catholyte circulation loop and direct the catholyte towards the membrane assembly through a plurality of emitters; 1. An electrodeposition system comprising: a liquid distribution system having:

2. 10. The electrodeposition system of claim 1, The electrodeposition system, wherein the plurality of flow barriers are integral with the membrane frame.

3. 10. The electrodeposition system of claim 1, 1. An electrodeposition system, wherein adjacent flow barriers define opposite walls of a divided volume, the plurality of flow barriers having openings proximal to the membrane frame, the openings fluidly connecting adjacent divided volumes.

4. 10. The electrodeposition system of claim 1, The electrodeposition system, wherein the plurality of washing conduits are formed in a distribution manifold fluidly connected to the catholyte circulation loop.

5. 5. The electrodeposition system of claim 4, An electrodeposition system wherein the distribution manifold is fluidly connected to the catholyte circulation loop through an inlet manifold of the membrane frame.

6. 6. The electrodeposition system of claim 5, An electrodeposition system wherein the distribution manifold is fluidly connected to the inlet manifold of the membrane frame via two or more inlets.

7. 7. The electrodeposition system of claim 6, The electrodeposition system, wherein the distribution manifold comprises one or more outlets opposite the two or more inlets.

8. 10. The electrodeposition system of claim 1, The electrodeposition system, wherein the membrane frame comprises a grid structure including a plurality of openings that expose the ion exchange membrane.

9. 9. The electrodeposition system of claim 8, The electrodeposition system, wherein the plurality of emitters are positioned to emit catholyte toward intersections of the grid structure.

10. 10. The electrodeposition system of claim 9, The electrodeposition system, wherein the plurality of emitters are positioned to emit catholyte toward alternating intersections of the grid structure.

11. 1. A fluid distribution system for an electrodeposition system, comprising: a membrane frame configured to support an ion exchange membrane, the membrane frame including a grid structure and a plurality of flow barriers extending from the grid structure; a plurality of flushing conduits, each flushing conduit of the plurality of flushing conduits configured to receive catholyte from the catholyte circulation loop and to direct the catholyte toward the membrane assembly through a plurality of emitters, the plurality of flushing conduits being positioned between adjacent flow barriers; A fluid distribution system comprising:

12. 12. The fluid distribution system of claim 11, The fluid distribution system, wherein the plurality of flow barriers are integral with the membrane frame.

13. 13. The fluid distribution system of claim 12, A fluid distribution system, wherein the plurality of cleaning conduits are formed in a distribution manifold fluidly connected to an inlet manifold of the membrane frame via two or more inlets.

14. 14. The fluid distribution system of claim 13, The distribution manifold includes one or more outlets opposite the two or more inlets.

15. 12. The fluid distribution system of claim 11, The grid structure includes a plurality of openings exposing the ion exchange membrane, and the plurality of emitters are positioned to emit catholyte toward intersections of the grid structure.

16. 16. The fluid distribution system of claim 15, The plurality of emitters are positioned to emit catholyte toward alternating intersections of the grid structure.

17. 1. A method for cleaning an ion exchange membrane in an electrodeposition system, comprising: flowing a catholyte in a first direction across a high resistance virtual anode (HRVA), the HRVA being separated from the ion exchange membrane by a membrane frame comprising a plurality of flow barriers extending from the membrane frame to the HRVA in a second direction transverse to the first direction; diverting some of the catholyte to a distribution manifold comprising a plurality of flushing conduits located between adjacent flow barriers, each flushing conduit configured to direct catholyte towards the membrane frame through a plurality of emitters; A method comprising:

18. 18. The method of claim 17, wherein diverting catholyte to the distribution manifold comprises diverting catholyte through two or more inlets fluidly connected to an inlet manifold of the membrane frame, the method further comprising diverting catholyte to one or more outlets of the distribution manifold, the one or more outlets being positioned opposite the inlet.

19. 18. The method of claim 17, The method of claim 1, wherein directing catholyte toward the membrane frame through a plurality of emitters comprises releasing the catholyte toward intersections of a grid structure of the membrane frame, the grid structure having a plurality of openings that expose the ion exchange membrane.

20. 20. The method of claim 19, The method, wherein discharging catholyte toward intersections of the grid structure comprises discharging catholyte toward alternating intersections of the grid structure.

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