Electroplating System

Abstract

Examples are disclosed relating to operating an electrodeposition system with an inert anode. In one exemplary system, the electrodeposition system includes a substrate holder and a cathode chamber configured to hold a catholyte. The anode chamber configured to hold the anolyte during the electrodeposition process includes an inert anode. An intermediate chamber is disposed between the cathode chamber and the anode chamber. The intermediate chamber is separated from the cathode chamber by an ion exchange membrane.

Description

[Background technology]

[0001] Electrodeposition can be used in integrated circuit manufacturing processes to deposit conductive films on substrates. Electrodeposition involves forming a film of a selected metal by electrochemically reducing dissolved ions of the selected metal to its elemental state on the substrate. Electrodeposition systems include a cathode physically coupled to the substrate and electrically coupled to an anode. One or more barriers may separate the cathode and anode into their respective plating chambers. Some anodes may be active anodes, providing the metal for electrodeposition. Other anodes may be inert anodes, which facilitate the electrodeposition reaction by oxidizing species other than the metal being deposited, such as water molecules. Summary of the Invention

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

[0003] Examples are disclosed relating to operating an electrodeposition system with an inert anode. In one exemplary system, the electrodeposition system includes a substrate holder. The electrodeposition system further includes a cathode chamber configured to hold a catholyte. The electrodeposition system further includes an anode chamber configured to hold the anolyte during the electrodeposition process. The anode chamber includes an inert anode. An intermediate chamber is disposed between the cathode chamber and the anode chamber. The intermediate chamber is separated from the cathode chamber by an ion exchange.

[0004] In some such instances, the intermediate chamber is separated from the anode chamber by a proton-inhibiting structure.

[0005] In some such examples, the proton-inhibiting structure additionally or alternatively comprises a metal redox barrier configured to undergo growth of a metal film on the anode side of the metal redox barrier by reduction of metal ions from an anolyte in contact with the anode side of the metal redox barrier, and configured to provide metal ions to a solution in contact with the cathode side of the metal redox barrier by oxidation of the metal redox barrier.

[0006] In some such instances, the electrodeposition system additionally or alternatively comprises a mechanical biasing element for biasing the metal redox barrier toward the intermediate chamber.

[0007] In some such examples, the metal redox barrier additionally or alternatively comprises one or more of copper, cobalt, nickel, tin, silver, gold, cadmium, platinum, or iron.

[0008] In some such examples, the metallic redox barrier is additionally or alternatively configured to be rotatable so that the anode and cathode sides alternate orientation toward the intermediate chamber.

[0009] In some such instances, the proton-inhibiting structure additionally or alternatively comprises an anion-exchange membrane.

[0010] In some such examples, the electrodeposition system additionally or alternatively comprises an intermediate chamber solution circulation system configured to circulate the intermediate chamber solution through the intermediate chamber.

[0011] In some such examples, the ion exchange membrane separating the intermediate chamber and the cathode chamber additionally or alternatively comprises a second anion exchange membrane.

[0012] In some such examples, the ion exchange membrane separating the intermediate chamber and the cathode chamber additionally or alternatively comprises a cation exchange membrane.

[0013] In some such examples, the electrodeposition system additionally or alternatively comprises a redox shuttle circulation system configured to provide a redox shuttle species to the anode chamber.

[0014] In some such instances, the redox shuttle circulation system additionally or alternatively comprises a redox shuttle species regeneration chamber.

[0015] In some such instances, the ion exchange membrane is additionally or alternatively a first cation exchange membrane, and the intermediate chamber is additionally or alternatively separated from the anode chamber by a second cation exchange membrane.

[0016] In some such examples, the electrodeposition system additionally or alternatively includes a copper oxide module fluidly coupled to the intermediate chamber.

[0017] Another example provides an electrodeposition system. The electrodeposition system includes a substrate holder. The electrodeposition system further includes a cathode chamber configured to hold a catholyte. The electrodeposition system further includes an anode chamber with an inert anode, the anode chamber configured to hold the anolyte. The electrodeposition system further includes a first ion exchange membrane disposed between the anode chamber and the cathode chamber. A redox shuttle circulation system is configured to provide a redox shuttle species to the anode chamber.

[0018] In some such instances, the first ion exchange membrane additionally or alternatively comprises an anion exchange membrane.

[0019] In some such examples, the electrodeposition system further comprises an intermediate chamber disposed between the cathode chamber and the anode chamber, the intermediate chamber additionally or alternatively separated from the anode chamber by an anion exchange membrane and additionally or alternatively separated from the cathode chamber by a cation exchange membrane, the intermediate chamber configured to hold an intermediate chamber solution during the electrodeposition process.

[0020] In some such instances, the electrodeposition system additionally or alternatively includes a source of metal ions fluidly coupled to the intermediate chamber.

[0021] In some such instances, the redox shuttle circulation system additionally or alternatively comprises a redox shuttle species regeneration chamber.

[0022] Another example provides an electrodeposition system comprising a substrate holder, the electrodeposition system further comprising a cathode chamber configured to hold a catholyte, the electrodeposition system further comprising an anode chamber with an inert anode, the anode chamber configured to hold the anolyte, and the electrodeposition system further comprising an anion exchange membrane separating the cathode chamber from the anode chamber.

[0023] Another example provides an electrodeposition system. The electrodeposition system includes a substrate holder. The electrodeposition system further includes a cathode chamber configured to hold a catholyte. The electrodeposition system further includes an anode chamber with an inert anode. The anode chamber is configured to hold the anolyte. The anode chamber is separated from the cathode chamber by a cation exchange membrane. The electrodeposition system further includes a copper oxide module fluidly coupled to the anode chamber.

[0024] Another example provides an electrodeposition system. The electrodeposition system includes a cathode chamber configured to hold a catholyte. The electrodeposition system further includes a substrate holder configured to expose a substrate to the catholyte during the electrodeposition process. The electrodeposition system further includes an inert anode assembly. The inert anode assembly includes one or more inert anodes and two or more anolyte flow channels. The two or more anolyte flow channels define segmented regions of anolyte flow across the one or more inert anodes. The inert anode assembly further includes an ion exchange membrane disposed between the cathode chamber and the two or more anolyte flow channels.

[0025] In some such examples, the inert anode assembly alternatively or additionally includes a cathode chamber bottom piece that includes an opening disposed opposite one of the two or more anolyte flow channels.

[0026] In some such examples, two or more anolyte flow channels are alternatively or additionally formed in the anolyte channel component, and an ion exchange membrane is alternatively or additionally disposed between the cathode chamber bottom component and the anolyte channel component.

[0027] In some such examples, the inert anode assembly alternatively or additionally includes an intermediate channel component disposed between the cathode chamber bottom component and the anolyte channel component. Alternatively or additionally, the ion exchange membrane is a first ion exchange membrane disposed between the intermediate channel component and the anolyte channel component. Alternatively or additionally, the electrodeposition system alternatively or additionally includes a second ion exchange membrane disposed between the cathode chamber bottom component and the intermediate channel component.

[0028] In some such examples, alternatively or additionally, the intermediate channel piece at least partially defines an intermediate flow channel, the intermediate flow channel comprising an opening disposed opposite one of the two or more anolyte flow channels from the anolyte flow channel.

[0029] In some such examples, the two or more anolyte flow channels are alternatively or additionally configured to produce a linear flow velocity in the range of 0.1 to 10 meters / second.

[0030] In some such examples, the one or more inert anodes alternatively or additionally comprise a first inert anode associated with the first anolyte flow channel and a second inert anode associated with the second anolyte flow channel.

[0031] In some such examples, the one or more inert anodes alternatively or additionally comprise a shared inert anode shared between at least two of the two or more anolyte flow channels.

[0032] Another example provides an inert anode assembly comprising one or more inert anodes and two or more anolyte flow channels, the two or more anolyte flow channels defining segmented regions of anolyte flow across the one or more inert anodes.

[0033] In some such examples, the inert anode assembly alternatively or additionally includes a cathode chamber bottom piece that includes an opening disposed opposite one of the two or more anolyte flow channels.

[0034] In some such examples, two or more anolyte flow channels are alternatively or additionally formed in the anolyte channel component, and the inert anode assembly alternatively or additionally includes an ion exchange membrane disposed between the cathode chamber bottom component and the anolyte channel component.

[0035] In some such examples, the inert anode assembly alternatively or additionally includes an intermediate channel component disposed between the cathode chamber bottom component and the anolyte channel component. The ion exchange membrane alternatively or additionally is a first ion exchange membrane disposed between the intermediate channel component and the anolyte channel component. The inert anode assembly alternatively or additionally includes a second ion exchange membrane disposed between the cathode chamber bottom component and the intermediate channel component.

[0036] In some such examples, alternatively or additionally, the intermediate channel piece at least partially defines an intermediate flow channel, the intermediate flow channel comprising an opening disposed opposite one of the two or more anolyte flow channels from the anolyte flow channel.

[0037] In some such examples, the one or more inert anodes alternatively or additionally comprise a first inert anode associated with the first anolyte flow channel and a second inert anode associated with the second anolyte flow channel.

[0038] In some such examples, the one or more inert anodes alternatively or additionally comprise a shared inert anode shared between at least two of the two or more anolyte flow channels.

[0039] Another example provides a method of operating an electrodeposition system. The electrodeposition system includes an inert anode assembly. The method includes placing a substrate in a cathode chamber of the electrodeposition system. The method further includes exposing the substrate to catholyte in the cathode chamber. The method further includes generating cations and gas bubbles in the anolyte at an inert anode of the inert anode assembly during the electrodeposition process. The method further includes flowing the anolyte through the anolyte flow channel at a linear flow rate sufficient to prevent accumulation of gas bubbles on an ion exchange membrane between the anolyte flow channel and the catholyte.

[0040] In some such instances, flowing the anolyte at a sufficient linear flow velocity alternatively or additionally includes flowing the anolyte at a linear flow velocity in the range of 0.1 to 10 meters / second.

[0041] In some such examples, flowing the anolyte at a sufficient linear flow rate alternatively or additionally includes restricting the anolyte flow to a segmented region by using two or more anolyte flow channels formed in an anolyte channel component of the inert anode assembly, the two or more anolyte flow channels comprising an anolyte flow channel.

[0042] In some such examples, generating cations and gas bubbles in the anolyte at the inert anode alternatively or additionally includes generating cations and gas bubbles in the anolyte in the first anolyte flow channel at the first inert anode and in the anolyte in the second anolyte flow channel at the second inert anode.

[0043] In some such examples, generating cations and gas bubbles in the anolyte at an inert anode alternatively or additionally includes generating cations and gas bubbles in the first anolyte flow channel and in the second anolyte flow channel using a shared inert anode.

[0044] Another example provides an inert anode assembly. The inert anode assembly includes an inert anode and an anolyte flow channel. The anolyte flow channel defines an area for anolyte flow across the inert anode. The anolyte flow channel comprises a length and a width. The width is less than the length. The anolyte flow channel includes a change in direction along the length.

[0045] In some such examples, the anode flow channel alternatively or additionally includes a helical path.

[0046] In some such examples, the anolyte flow channel alternatively or additionally includes a tortuous path.

[0047] Another example provides an electrodeposition system including a cathode chamber configured to hold a catholyte, an anode chamber configured to hold an anolyte, and a membrane frame supporting an ion exchange membrane disposed between the cathode chamber and the anode chamber. The electrodeposition system further includes a substrate holder configured to expose the substrate to the catholyte during the electrodeposition process. An inert anode is disposed within the anode chamber. A bubble diverter is disposed to direct a flow of gas bubbles generated at the inert anode to a stationary structure where the gas bubbles are vented to the atmosphere.

[0048] In some such instances, the bubble diverter additionally or alternatively extends around a peripheral portion of the ion exchange membrane.

[0049] In some such examples, the bubble diverter additionally or alternatively comprises a plurality of apertures configured to expose the ion exchange membrane to an ionic current flowing between the inert anode and the substrate.

[0050] In some such examples, the electrodeposition system additionally or alternatively includes an adjustment mechanism configured to adjust the open cross-sectional area of the plurality of apertures.

[0051] In some such examples, the plurality of apertures are additionally or alternatively located at the lower end of the bubble diverter, and the adjustment mechanism additionally or alternatively includes a mechanism for adjusting the position of the bubble diverter relative to the base of the anode chamber.

[0052] In some such instances, the electrodeposition additionally or alternatively includes an anolyte circulation loop, and the bubble diverter additionally or alternatively directs the flow of bubbles into the anolyte circulation loop.

[0053] In some such examples, the anolyte circulation loop additionally or alternatively includes a circulation pump, and the stationary structure additionally or alternatively is located upstream of the circulation pump, and the stationary structure is exposed to atmosphere.

[0054] In some such examples, the anolyte circulation loop additionally or alternatively includes a contactor downstream of the stationary structure and upstream of the circulation pump, the contactor configured to remove dissolved gases from the anolyte.

[0055] Another example provides a bubble diverting system for an electrodeposition system, the bubble diverting system comprising a bubble diverter configured to be attached to an anode chamber of the electrodeposition system, the bubble diverter comprising a wall configured to partially separate a region of the anode chamber adjacent an ion exchange membrane from a region of the anode chamber configured to direct a flow of bubbles into an anolyte circulation loop.

[0056] In some such instances, the bubble diverter is additionally or alternatively configured to extend around a peripheral portion of the ion exchange membrane.

[0057] In some such examples, the bubble diverter additionally or alternatively comprises a plurality of apertures configured to expose the ion exchange membrane to an ionic current flowing between the inert anode and the substrate.

[0058] In some such examples, the bubble diverting system additionally or alternatively comprises an adjustment mechanism configured to adjust the open cross-sectional area of the plurality of apertures.

[0059] In some such instances, the adjustment mechanism additionally or alternatively comprises a shutter system.

[0060] In some such examples, the bubble diverting system additionally or alternatively comprises a stationary port configured to direct the bubbles from the anode chamber to a stationary structure.

[0061] In some such examples, the stationary port additionally or alternatively leads to a channel configured to connect to an anolyte circulation loop.

[0062] According to another example, a method of operating an electrodeposition system is provided, the method including generating gas bubbles at an inert anode disposed in an anode chamber of the electrodeposition system, the method further including directing the gas bubbles generated at the inert anode to a stationary structure using a gas bubble diverter, the stationary structure being exposed to the atmosphere.

[0063] In some such examples, directing the bubbles to the stationary structure additionally or alternatively includes deflecting the stream of bubbles into at least one channel that leads to the anolyte circulation loop.

[0064] In some such instances, the method additionally or alternatively includes flowing the anolyte through the anolyte circulation loop such that gas bubbles enter a stationary structure upstream of the circulation pump.

[0065] In some such examples, the method additionally or alternatively includes generating an ion current at an inert anode, passing the ion current through apertures in a bubble diverter, and adjusting the ion current at the substrate by adjusting the open cross-sectional area of at least one aperture in the bubble diverter in response to a plating performance indicator.

[0066] In some such instances, adjusting the ion current additionally or alternatively includes maintaining a voltage applied between the inert anode and the substrate. [Brief explanation of the drawings]

[0067] [Figure 1] FIG. 1 is a block diagram of an exemplary electrodeposition tool.

[0068] [Figure 2] FIG. 2 shows a schematic of an exemplary electrodeposition cell with an inert anode.

[0069] [Figure 3] FIG. 3 shows a schematic of an exemplary electrodeposition system with an inert anode and a proton-blocking structure.

[0070] [Figure 4] FIG. 4 shows a schematic of an exemplary electrodeposition system with a metal redox barrier.

[0071] [Figure 5] FIG. 5 shows a schematic of an exemplary electrodeposition system with a rotatable metal redox barrier.

[0072] [Figure 6A] FIG. 6A shows a schematic of an exemplary electrodeposition system including an inert anode, a cation exchange membrane, and an anion exchange membrane.

[0073] [Figure 6B] FIG. 6B is a plot showing the change in bath ion concentration over time for the exemplary embodiment of the electrodeposition system of FIG. 6A.

[0074] [Figure 7] FIG. 7 shows a schematic of an exemplary electrodeposition system equipped with an inert anode redox shuttle circulation system.

[0075] [Figure 8] FIG. 8 shows a schematic of an exemplary chemical reaction for the electrodeposition system of FIG.

[0076] [Figure 9A] FIG. 9A shows a schematic of an exemplary electrodeposition system including an inert anode, a first anion exchange membrane, and a second anion exchange membrane.

[0077] [Figure 9B] FIG. 9B is a plot showing the change in bath ion concentration over time for the exemplary embodiment of the electrodeposition system of FIG. 9A.

[0078] [Figure 10] FIG. 10 shows an exemplary electrodeposition system including an inert anode, a first cation exchange membrane, a second cation exchange membrane, and a copper oxide module.

[0079] [Figure 11A] FIG. 11A shows a schematic of an exemplary electrodeposition system with an inert anode and an anion exchange membrane.

[0080] [Figure 11B] FIG. 11B is a plot showing the change in bath concentration over time for the exemplary embodiment of the electrodeposition system of FIG. 11A.

[0081] [Figure 12] FIG. 12 is a flow diagram illustrating an exemplary method for forming a layer of a selected metallic material on a substrate by electrodeposition.

[0082] [Figure 13] FIG. 13 is a block diagram of another exemplary electrodeposition system.

[0083] [Figure 14] FIG. 14 schematically illustrates a top view of an exemplary inert anode assembly.

[0084] [Figure 15] FIG. 15 shows a schematic exploded view of the inert anode assembly of FIG.

[0085] [Figure 16] FIG. 16 is a schematic cross-sectional side view taken along line 5-5 in FIG.

[0086] [Figure 17] FIG. 17 illustrates a schematic of an exemplary inert anode assembly having a shared inert anode.

[0087] [Figure 18] FIG. 18 shows a schematic of an exemplary inert anode assembly having a spiral-path anolyte flow channel.

[0088] [Figure 19] FIG. 19 illustrates a schematic of an exemplary inert anode assembly having a serpentine path anolyte flow channel.

[0089] [Figure 20] FIG. 20 illustrates a schematic of an exemplary inert anode assembly having an intermediate channel component.

[0090] [Figure 21] FIG. 21 is a flow diagram of an exemplary method of operating an electrodeposition system with an inert anode.

[0091] [Figure 22] FIG. 22 is a block diagram of another exemplary electrodeposition system.

[0092] [Figure 23] FIG. 23 is a diagram illustrating ion current and oxygen bubble movement in an exemplary electrodeposition system.

[0093] [Figure 24]FIG. 24 shows a schematic of an anolyte circulation loop with a quiescent region.

[0094] [Figure 25] FIG. 25 shows a schematic top view of an electrodeposition system with a peripheral inert anode and a bubble diverter.

[0095] [Figure 26A] FIG. 26A shows an exemplary bubble diverter with a shuttered aperture. [Figure 26B] FIG. 26B shows an exemplary bubble diverter with a shuttered aperture.

[0096] [Figure 27A] FIG. 27A illustrates an exemplary repositioning of the bubble diverter relative to the base of the anode chamber. [Figure 27B] FIG. 27B illustrates an exemplary repositioning of the bubble diverter relative to the base of the anode chamber.

[0097] [Figure 28] FIG. 28 is a flow diagram of an exemplary method of operating an electrodeposition system with an inert anode.

[0098] [Figure 29] FIG. 29 is a flow diagram of an exemplary method for adjusting ion current in an electrodeposition system with an inert anode.

[0099] [Figure 30] FIG. 30 illustrates a schematic diagram of an exemplary computing system. DETAILED DESCRIPTION OF THE INVENTION

[0100] The term "acidic species" generally refers to an atom or molecule in neutral or ionic form that is capable of donating a proton or accepting an electron pair.

[0101] The term "active anode" generally refers to the electrode in an electrodeposition system that is formed from the metal being electrodeposited and that is consumed by oxidation during the electrodeposition process.

[0102] The term "anion exchange membrane" generally refers to a membrane that selectively allows the passage of one or more anionic species while inhibiting the transport of other species, such as cationic and organic species.

[0103] The term "anode" generally refers to the conductive structure where electrochemical oxidation occurs during the electrodeposition process.

[0104] The term "anode chamber" generally refers to the physical structure configured to hold at least the anode and anolyte in an electrodeposition system.

[0105] The term "anode chamber base" generally refers to the underside of the anode chamber.

[0106] The term "anode side" generally refers to the side of an electrodeposition system component that faces the inert anode of the electrodeposition system.

[0107] The term "anolyte" generally refers to the solution used in the anode chamber during the electrodeposition process.

[0108] The term "anolyte circulation loop" generally refers to the path by which anolyte recirculates through the anode chamber over time.

[0109] The term "anolyte flow channel" generally refers to a structure that defines a fluid flow path for anolyte across an inert anode. The fluid flow path is comprised of a width and a length, where the width is less than the length.

[0110] The term "anolyte channel component" generally refers to a structure that defines at least a portion of an anolyte flow channel.

[0111] The term "aperture" generally refers to a hole or opening in a partition that allows passage of molecules from one side of the partition to the other side of the partition.

[0112] The term "bubble diverter" generally refers to a structure that deflects the flow of gas bubbles in a solution to a preselected point.

[0113] The term "bubble diversion system" generally refers to a system that includes a bubble diverter and at least a conduit for removing air bubbles from a chamber that holds a solution.

[0114] The term "cathode" generally refers to the conductive layer on a substrate that grows during electrodeposition by the electrochemical reduction of ions.

[0115] The term "cathode chamber" generally refers to the physical structure configured to hold at least the cathode and catholyte in an electrodeposition system.

[0116] The term "cathode chamber bottom piece" generally refers to the structure that defines the surface of the cathode chamber adjacent to the ion exchange membrane that separates the cathode chamber from other fluid environments of the electrodeposition system, such as the intermediate flow channel and the anolyte flow channel.

[0117] The term "cathode side" typically refers to the side of an electrodeposition system component that faces the substrate holder of the electrodeposition system.

[0118] The term "catholyte" generally refers to the solution used in the cathode chamber during the electrodeposition process.

[0119] The term "cation exchange membrane" generally refers to a permeable membrane that selectively allows the passage of one or more cationic species while preventing the transport of other species, such as anionic and organic species.

[0120] The term "circulation pump" generally refers to a pump that recirculates liquid and / or gas through a circulation loop.

[0121] The term "contactor" generally refers to a device with a membrane configured to remove dissolving gases from the solution.

[0122] The term "dissolved gas" generally refers to gas molecules dissolved in a solvent.

[0123] The terms "electrodeposition," "electroplating," "plating," "deposition," and variations thereof generally refer to the process of reducing dissolved ions of one or more metals onto a substrate surface to form a film of one or more metals.

[0124] The term "electrodeposition cell" generally refers to a processing station within an electrodeposition system for performing electrodeposition on a substrate.

[0125] The term "electrodeposition system" generally refers to a machine configured to perform electrodeposition.

[0126] The term "gas bubbles" typically refers to gas phase by-product bubbles that are produced at the inert anode during the electrodeposition process.

[0127] The term "inert anode" generally refers to an electrode material that is electrically conductive but is not electrochemically oxidized during the electrodeposition process.

[0128] The term "inert anode assembly" generally refers to an assembly of parts including an inert anode and an anolyte channel part.

[0129] The term "intermediate chamber" generally refers to a physical structure that is disposed between the cathode chamber and the anode chamber and that provides selective isolation from the chemical environments of the cathode and anode chambers.

[0130] The term "intermediate chamber solution" generally refers to the solution used in the intermediate chamber during the electrodeposition process.

[0131] The term "intermediate chamber solution circulation system" generally refers to the path by which the intermediate chamber solution is recirculated over time.

[0132] The term "intermediate channel component" generally refers to a structure that defines at least a portion of an intermediate flow channel.

[0133] The term "intermediate flow channel" generally refers to a structure that defines a fluid flow path for an intermediate electrolyte. The intermediate flow channel is separated from the anolyte flow channel by a first ion exchange membrane and from the catholyte flow channel by a second ion exchange membrane.

[0134] The term "ionic current" generally refers to the flow of charge through a conductive solution.

[0135] The term "ion exchange membrane" generally refers to a semipermeable membrane that allows the transport of certain dissolved ions but not other dissolved ions or neutrally charged molecules.

[0136] The term "linear flow rate" generally refers to the distance traveled by the anolyte in a unit of time.

[0137] The term "bottom of the bubble diverter" generally refers to the portion of the bubble diverter that is adjacent the base of the anode chamber.

[0138] The term "mechanical biasing element" generally refers to a device configured to apply a mechanical force along a certain direction.

[0139] The term "membrane frame" generally refers to a structural device that can mount and secure a membrane in place.

[0140] The term "membrane interface seal" generally refers to a material that is placed between a membrane and an adjacent structure to prevent solution flow between the membrane and the adjacent structure.

[0141] The term "metal film" generally refers to a layer of metal deposited on a substrate.

[0142] The term "metal ion" generally refers to a metal atom in a dissolved oxidation state.

[0143] The term "metal redox barrier" generally refers to a physical barrier that prevents the movement of protons and gas bubbles while allowing electrical current to flow. Electric current flows due to oxidation of the metal redox barrier on its cathode-facing surface and reductive deposition of metal atoms on its anode-facing surface.

[0144] The term "cross-sectional open area" generally refers to the two-dimensional extent of an aperture.

[0145] The term "proton-impeding structure" generally refers to any barrier that inhibits the migration of protons out of the anode chamber in an electrodeposition cell.

[0146] The term "redox shuttle circulation system" generally refers to a circulation bath loop configured to provide a flow of a species that is preferentially oxidized over water to an inert anode.

[0147] The term "redox shuttle species regeneration chamber" generally refers to the portion of the redox shuttle circulation system that regenerates species that have been preferentially oxidized over water by the inert anode.

[0148] The term "segmented region of anolyte flow" and its variants generally refers to the flow of anolyte across one or more inert anodes that are spatially separated by solid physical structures.

[0149] The term "shared inert anode" generally refers to a contiguous inert anode configured to contact the anolyte in two or more anolyte flow channels.

[0150] The term "shutter system" generally refers to a device that can be moved to increase or decrease the open cross-sectional area of an aperture.

[0151] The term "static port" generally refers to an opening in a chamber that leads to a static area exposed to the atmosphere.

[0152] The term "static structure" generally refers to a device that vents gas bubbles in a solution to the atmosphere.

[0153] The term "substrate" generally refers to any object onto which a film can be deposited by electrodeposition.

[0154] The term "substrate holder" generally refers to a device configured to receive a substrate and hold it in position for metal film electrodeposition.

[0155] Electrochemical deposition processes are widely used in the semiconductor industry for device metallization. Exemplary metallization processes include the electrodeposition of copper and cobalt onto chips and other substrates. Other metals commonly used in electrodeposition processes include tin / silver alloys, nickel, and gold.

[0156] Some electrodeposition systems use consumable or active anodes. Active anodes are typically composed of the same metal being deposited at the cathode. Active anodes consume over time. This consumption necessitates periodic replacement, recalibration, and corresponding tool downtime. Furthermore, active anodes are expensive and, for some metals, can be difficult to source. To avoid these issues, electrodeposition systems can utilize inert anodes. Inert anodes do not consume over time. However, inert anodes promote electrolytic reactions in the anode chamber, generating proton and oxygen bubbles. These bubbles can interfere with electrodeposition. For example, oxygen bubbles can accumulate under the ion-exchange membrane separating the anode and cathode chambers of an electrodeposition system. These bubbles can block the target substrate, interrupting ionic current through the ion-exchange membrane and resulting in uneven electrodeposition. Furthermore, without an anode as a source of plating ions, more aggressive cathode bath management may be required to prevent plating ion depletion.

[0157] Thus, exemplary electrodeposition systems are disclosed that can address issues related to the generation of proton and oxygen bubbles by an inert anode. Briefly, in some examples, a proton-inhibiting structure separates the anode chamber from the intermediate chamber. Additionally, an ion-exchange membrane separates the intermediate chamber from the cathode chamber. In some such examples, the proton-inhibiting structure comprises a metal redox barrier. In other such examples, the proton-inhibiting structure comprises a second ion-exchange membrane. Additionally, in some such examples, a redox shuttle circulation system is provided to help further reduce acid generation at the inert anode. The redox shuttle circulation system may include a regeneration chamber to help maintain chemical species concentrations in the anolyte.

[0158] Before describing these examples in more detail, FIG. 1 schematically illustrates a block diagram of an exemplary electrodeposition tool 100. The electrodeposition tool 100 is comprised of an electrodeposition cell 102 having an anode chamber 104 and a cathode chamber 106. The electrodeposition tool 100 further comprises an ion exchange membrane 108 separating the anode chamber 104 and the cathode chamber 106. In various examples, the ion exchange membrane 108 may comprise a cation exchange membrane or an anion exchange membrane. The electrodeposition tool 100 further comprises a high resistance virtual anode (HRVA) 109 within the cathode chamber 106.

[0159] The anode chamber 104 contains an anode 110. The anode chamber 104 further contains an anolyte. The cathode chamber 106 contains a catholyte. The catholyte contains ionic species that are deposited on the cathode layer of the substrate 111 as a metal by electrochemical reduction. The anode 110 may be comprised of an inert anode. Bulk anolyte and / or catholyte solution may be added from time to time to replenish the ionic species.

[0160] The ion exchange membrane 108 prevents organic and anionic species from passing between the cathode chamber 106 and the anode chamber 104, while allowing metal ions to pass from the anode chamber 104 to the cathode chamber 106. The HRVA 109 comprises an ionic resistance element, which is in proximity to a suitably constant and uniform current source in proximity to the substrate cathode.

[0161] The electrodeposition tool 100 further includes a proton inhibiting structure 112 disposed between the anode 110 and the ion exchange membrane 108 to reduce acidification of the catholyte. The proton inhibiting structure 112 forms a boundary of an intermediate chamber 115 positioned between the anode chamber 104 and the cathode chamber 106. Another boundary of the intermediate chamber 115 may be formed by the ion exchange membrane 108. The intermediate chamber 115 may contain an intermediate solution. The intermediate solution may include ionic species to be deposited on the cathode layer.

[0162] The substrate holder 122 is coupled to a substrate holder movement system 123. The substrate holder movement system 123 includes a lift 124 configured to adjust the distance between the substrate holder 122 and the HRVA 109. For example, the lift 124 may lower the substrate holder 122 to place the substrate 111 in the catholyte for electrodeposition. The lift 124 may further raise the substrate holder 122 from the catholyte after electrodeposition. The substrate holder movement system 123 may further include components for controlling the opening and closing of the substrate holder 122.

[0163] Catholyte may be circulated between the cathode chamber 106 and the catholyte reservoir 130 by a combination of gravity and one or more pumps 132. Similarly, anolyte may be circulated through the anolyte reservoir 134 and the anode chamber 104 by a combination of gravity and one or more pumps 136. Additionally, intermediate solution may be circulated through an intermediate solution reservoir 138 by a combination of gravity and one or more pumps 140.

[0164] Some electrodeposition tools may use multiple plating cells to perform plating operations on multiple substrates in parallel. In some such examples, a central catholyte and / or anolyte reservoir may supply catholyte and / or anolyte to multiple plating cells. In other such examples, separate catholyte and / or anolyte reservoirs may be used to supply multiple plating cells. In still other examples, the electrodeposition tool may include a single plating cell. When the electrodeposition tool includes multiple plating cells, a single lift may be configured to lift two or more substrate holders for two or more different plating cells.

[0165] After the substrate 111 is loaded into the substrate holder 122, the substrate holder 122 is lowered toward the HRVA 109 by a lift 124. The substrate 111 faces the surface of the HRVA 109 and is separated from the HRVA 109 by a plating gap during electrodeposition. An electric field is established between the anode 110 and the substrate 111. This electric field drives dissolved metal cations from the anode chamber 104 and / or intermediate chamber 115 into the cathode chamber 106. At the substrate 111, the metal cations are electrochemically reduced to deposit a metal film on the substrate 111. An anode potential is applied to the anode 110 via an anode electrical connection 142, and a cathode potential is applied to the cathode of the substrate 111 via a cathode electrical connection 146 to complete a circuit. In some examples, the substrate holder 122 may be rotated via a rotation motor 148 during electrodeposition.

[0166] The electrodeposition tool 100 may further include a computing system 150, aspects of which are described in more detail below with respect to FIG. 30 . The computing system 150 may include executable instructions to control any suitable function of the electrodeposition tool 100. Exemplary functions include the electrodeposition process and the substrate loading / unloading process. In some examples, the computing system 150 may be configured to communicate with a remote computing system 152 over a suitable computer network. The remote computing system 152 may comprise any suitable computing system. Examples include a networked workstation computer, an enterprise computing system, and / or a cloud computing system. It will be understood that the remote computing system 152 may communicate with and control multiple electrodeposition tools in some examples.

[0167] Active anodes can be used more frequently than inactive anodes. However, as mentioned above, a drawback to using active anodes is that they eventually wear out over time. Therefore, new anodes are installed periodically. Active anodes are expensive and can be difficult to source for some metals. Additionally, anode replacement leads to downtime for the electrodeposition system. Anode replacement may also require requalification and defect control of the electrodeposition system after anode installation. Productivity loss from anode replacement can reduce the throughput of the electrodeposition system and increase the cost of ownership of the electrodeposition system.

[0168] In contrast, as mentioned above, inert anodes do not consume over time. Therefore, their use does not result in downtime due to anode replacement. These features make inert anodes an attractive alternative to active anodes.

[0169] However, as noted above, an inert anode can generate proton and oxygen bubbles. Figure 2 schematically illustrates an exemplary electrodeposition system 200 with an inert anode and illustrates the formation of proton and oxygen bubbles. Figure 2 is illustrated in the context of copper deposition; however, bubbles can also occur when electrodepositing other metals.

[0170] The electrodeposition system 200 includes an anode chamber 202 and a cathode chamber 204. The electrodeposition system 200 further includes an ion exchange membrane 206 separating the anode chamber 202 and the cathode chamber 204. The electrodeposition system 200 further includes an HRVA 210 disposed within the cathode chamber 204.

[0171] The anode chamber 202 contains an anolyte reservoir 212 in which an inert anode 214 is placed. The cathode chamber 204 contains ionic copper (Cu) that is deposited on a substrate 218, which serves as the cathode. 2+) in a catholyte reservoir 216 containing an inert anode 214. A substrate 218 is held in a substrate holder 219 during deposition. The anolyte reservoir 212 is placed in an anolyte circulation loop 220. The catholyte reservoir 216 is placed in a catholyte circulation loop 222. A voltage source 230 applies a voltage across the substrate 218 and the inert anode 214 to cause a flow of copper ions for deposition onto the substrate 218.

[0172] The cation exchange membrane 206 is made of Cu 2+ The ions pass from the anolyte reservoir 212 to the catholyte reservoir 216. Cu across the cation exchange membrane 206 2+ The ions replace at least some of the copper ions in the catholyte reservoir 216 that are reduced on the substrate 218 .

[0173] At the inert anode of FIG. 2, the oxidation and reduction reactions include: 2H2O→O 2 +4H + +4e - (on an inert anode) Cu +2 +2e - → Cu (on the cathode) 2Cu 2+ +2H2O→2Cu+4H + +O2 (overall reaction)

[0174] Thus, unlike an active anode, the inactive anode 214 does not generate metal cations in the anolyte bath. Instead, the inactive anode 214 oxidizes water molecules to form molecular oxygen. For every mole of copper plated at the cathode, 0.5 moles of molecular oxygen and 2 moles of protons (H + ) occurs at the inert anode.

[0175] Bubbling and bubble accumulation in the cation exchange membrane 206 can affect plating uniformity. Additionally, protons generated on the anode surface lower the pH of the anolyte reservoir. Protons can also cross the membrane into the catholyte reservoir. Also, maintaining a mass balance of, for example, copper in the anode chamber reservoir during the electrodeposition process can be difficult.

[0176] The challenge of maintaining mass balance in the presence of an inert anode also includes concentration fluctuations in the anolyte and catholyte solutions, which are caused by at least three factors: (1) acid generation on the anode surface, (2) acid crossing across the cation exchange membrane to the catholyte side, requiring water dosing / discharge to maintain plating specifications, and (3) consumption of metal ions on the cathode surface.

[0177] FIG. 3 schematically illustrates an exemplary electrodeposition system 300 that can help address problems caused by the generation of proton and oxygen bubbles. The electrodeposition system 300 includes an inert anode 304 disposed within an anode chamber 302. The anode chamber 302 is configured to hold an anolyte reservoir 306 during the electrodeposition process. The anolyte reservoir 306 may be replenished via an anolyte circulation loop 308. The inert anode 304 may be constructed from any suitable material that is resistant to oxidation during the electrodeposition process. Examples include mixed metal oxides or conductive noble metals (e.g., platinum or iridium coated with one or more metal oxides).

[0178] The electrodeposition system 300 further includes a proton inhibiting structure 310. The proton inhibiting structure 310 is configured to impede the migration of protons and oxygen bubbles resulting from the electrolysis of water in the anolyte reservoir 306. This may help prevent protons from migrating to the catholyte reservoir 324. This may also help prevent oxygen bubbles from accumulating on the ion exchange membrane 318. In various examples, the proton inhibiting structure 310 may include one or more of a metal redox barrier, an anion exchange membrane, or other structural element that provides a barrier to proton migration.

[0179] A proton-inhibiting structure 310 may define a boundary of the intermediate chamber 312. The intermediate chamber 312 may be configured to hold an intermediate reservoir 314. The intermediate reservoir 314 may be replenished via an intermediate reservoir circulation loop 316. The intermediate reservoir 314 may include at least a source of metal cations for electrodeposition. In other examples, such as the example described with respect to FIG. 10 , the boundary between the intermediate chamber 312 and the anode chamber 302 may be defined by a structure that does not provide a barrier to proton migration, such as an anion exchange membrane. Such a structure may prevent the accumulation of gas bubbles, restrict or inhibit the passage of one or more molecule types between the intermediate chamber 312 and the anode chamber 302, and / or provide a separation between two adjacent chambers.

[0180] The electrodeposition system 300 further comprises an ion exchange membrane 318. The ion exchange membrane 318 may define another boundary of the intermediate chamber 312. The ion exchange membrane 318 separates the intermediate chamber 312 from the cathode chamber 322. The ion exchange membrane 318 selectively allows ions to be transported between the intermediate chamber 314 and the catholyte chamber 324.

[0181] The cathode chamber 322 further includes a HRVA 326 and a substrate holder 328. The substrate holder 328 may be configured to expose a cathode layer of a substrate 330 disposed within the substrate holder 328 to the catholyte bath 324 during the electrodeposition process. The cations for electrodeposition are represented by Cat + It is shown as follows. + may represent any suitable metal ion used to grow a metal layer in an electrodeposition process. Catholyte reservoir 324 may be replenished via catholyte circulation loop 332. A voltage source 334 may apply a voltage across inert anode 304 and substrate 330 to facilitate the electrodeposition process.

[0182] As mentioned above, the proton-inhibiting structure 310 may include a metal redox barrier in some examples. The metal redox barrier may comprise a physical barrier that blocks the movement of protons and gas bubbles while allowing current to flow. Current flows due to oxidation of the metal redox barrier on its cathode-facing surface and reductive deposition of metal atoms on its anode-facing surface.

[0183] 4 illustrates an exemplary electrodeposition system 400 with a metal redox barrier 410. The electrodeposition system 400 is an example of the electrodeposition system 300. Briefly, the electrodeposition system 400 includes an anode chamber 402 with an inert anode 404. The anode chamber 402 is configured to hold an anolyte reservoir 406 that can be replenished via an anolyte circulation loop 408.

[0184] A metal redox barrier 410 separates the intermediate chamber 412 from the anode chamber 402. The intermediate chamber 412 may be configured to hold an intermediate reservoir 414. The intermediate reservoir 414 may be replenished via an intermediate reservoir circulation loop 416. A cation exchange membrane 418 separates the intermediate chamber 412 from the cathode chamber 422. In some examples, the same anolyte solution, such as a copper sulfate solution, may be used for both the intermediate reservoir 414 and the anolyte reservoir 406. In other examples, separate solutions may be used for the intermediate reservoir 414 and the anolyte reservoir 406. The intermediate reservoir 414 and the anolyte reservoir 406 may be continuously replenished via an anolyte circulation loop 408 and an intermediate reservoir circulation loop 416, respectively. Due to the formation of protons during electrodeposition, the anolyte reservoir 406 may be more acidic than the intermediate reservoir 414. However, the intermediate reservoir 414 and the anolyte reservoir 406 may be supplied from the same original source, with one or both reservoirs being doped or diluted prior to entering their respective chambers.

[0185] The cathode chamber 422 further includes an HRVA 426 and a substrate holder 428. A substrate 430 with a cathode layer may be placed in the substrate holder 428 and exposed to the catholyte reservoir 424 during the electrodeposition process. The catholyte reservoir 424 may be replenished via a catholyte circulation loop 432. A voltage source 434 may apply a voltage across the inert anode 404 and the substrate 430 to facilitate the electrodeposition process.

[0186] The metal redox barrier 410 may comprise a passive metal plate disposed in an electric field generated by a voltage source 434 across the cathode layer of the substrate 430 and the inert anode 404. This may allow for convenient retrofitting of existing electrodeposition system configurations. The metal redox barrier 410 may comprise any suitable metal. Examples include one or more of copper, cobalt, gold, silver, tin, zinc, nickel, cadmium, platinum, iron, or alloys such as brass or tin-silver. In some examples, the metal redox barrier 410 may comprise a metal layer on a substrate. The metal layer participates in oxidation and reduction reactions. In other examples, the metal redox barrier 410 may include a bulk portion formed from a metal that participates in oxidation and reduction reactions. While described in terms of a passive metal plate, in other examples, an electric potential may be applied to the metal redox barrier 410.

[0187] During electrodeposition, the metal redox barrier 410 may undergo growth of a metal film on the anodic side of the metal redox barrier 410 by reduction of metal ions from the anolyte reservoir 406. Additionally, the metal redox barrier 410 may provide metal ions to an intermediate reservoir 414 on the cathodic side of the metal redox barrier 410 by oxidation of the metal redox barrier 410.

[0188] As an example, copper metal is deposited (reduced) on the anode side of the metallic redox barrier 410, and copper ions are released (oxidized) on the cathode side of the metallic redox barrier 410. The resulting copper ions then cross the cation exchange membrane 418, enter the catholyte reservoir 424, and are reduced on the substrate 430. In this manner, the release of copper ions from the metallic redox barrier 410 maintains the amount of copper present in the catholyte reservoir 424.

[0189] In the case of copper, the main reaction is: 2H2O-4e→4H + +O2 (on inert anode) Cu 2+ +2e → Cu (anode side of barrier) Cu-2e → Cu 2+ (cathode side of barrier) In the absence of mass transport limitations, the Gibbs free energy would normally favor such reactions at the metal redox barrier during plating. This copper replenishment preserves the mass balance of the catholyte. In this way, the metal redox barrier 410 acts similar to an active anode. The metal redox barrier 410 also helps maintain the desired acid concentration in the intermediate reservoir 414 by preventing protons from migrating into the intermediate reservoir 414.

[0190] Because copper deposits on the anode side of the metal redox barrier 410 and dissolves on the cathode side, the net thickness of the plate may remain substantially constant over time. However, the metal redox barrier 410 may migrate toward the inert anode 404 over time. Therefore, in some examples, one or more mechanical biasing elements 440 may be used to bias the metal redox barrier 410 toward the intermediate chamber 412. As an example, the mechanical biasing element 440 may include a spring mechanism that biases the position of the metal redox barrier 410. This may help maintain an appropriate and consistent distance between the substrate 430 and the metal redox barrier 410. A suitable seal 442 may be used to prevent air bubbles and acid from migrating around the sides of the metal redox barrier 410.

[0191] The metal redox barrier 410 may not be depleted or replenished evenly across both sides over time. Therefore, the metal redox barrier 410 may be replaced from time to time. However, replacement of the metal redox barrier 410 may occur less frequently than with an active anode. Therefore, using the metal redox barrier 410 may result in less downtime than using an active anode. Furthermore, replacing the metal redox barrier 410 may be less time-consuming and less costly than replacing an active anode. Relatively thick metal films may be plated on the substrate without concern for anode passivation due to precipitation caused by localized increases in metal ion concentration. Additionally, gas bubbles emanating from the inactive anode 404 are prevented from reaching the cation exchange membrane 418. This may help prevent gas bubbles collecting on the cation exchange membrane 418 from affecting plating uniformity. Control of the concentration of chemical species may also be facilitated by the continuous consumption and release of metal in the presence of an electric field.

[0192] 4, one or more mechanical biasing elements are used to maintain a suitably consistent spacing between the metal redox barrier 410 and the cation exchange membrane 418. In other examples, the metal redox barrier may be periodically rotated. By rotating the metal redox barrier, the surface of the metal redox barrier can be subjected to both oxidation and reduction over time.

[0193] 5 illustrates an example of an electrodeposition system 500 with a metal redox barrier 510 (e.g., a rotatable metal redox barrier). The electrodeposition system 500 is an example of the electrodeposition system 300. Briefly, the electrodeposition system 500 includes an anode chamber 502 with an inert anode 504. The anode chamber 502 is configured to hold an anolyte reservoir 506 that can be replenished via an anolyte circulation loop 508.

[0194] A metal redox barrier 510 separates an intermediate chamber 512 from the anode chamber 502. The intermediate chamber 512 may be configured to hold an intermediate reservoir 514. The intermediate reservoir 514 may be replenished via an intermediate reservoir circulation loop 516.

[0195] A cation exchange membrane 518 separates the intermediate chamber 512 from the cathode chamber 522. The cation exchange membrane 518 allows for selective transport of cations between the intermediate chamber 514 and the catholyte chamber 524. The cathode chamber 522 further includes a HRVA 526 and a substrate holder 528. A substrate 530 with a cathode layer may be placed in the substrate holder 528 and exposed to the catholyte chamber 524 during the electrodeposition process. The catholyte chamber 524 may be replenished via a catholyte circulation loop 532. A voltage source 534 may apply a voltage across the inert anode 504 and the substrate 530 to facilitate the electrodeposition process.

[0196] The metal redox barrier 510 is rotatable so that the anode and cathode sides of the plates can alternate their respective orientations toward the intermediate chamber 512. In some examples, the metal redox barrier 510 may be rotated manually by an operator. In other examples, the metal redox barrier 510 may rotate automatically. For example, FIG. 5 shows the metal redox barrier 510 rotatably coupled to a motor box 540 via a shaft 542.

[0197] The electrodeposition system 500 may plate metal onto the anode side of the metal redox barrier 510 after one or more plating cycles. The electrodeposition system 500 may then rotate the metal redox barrier 510 so that the last-plated metal side undergoes oxidation during one or more plating cycles. In some examples, the amount of metal consumed may be monitored, and the metal redox barrier 510 may be rotated when the consumed metal reaches a threshold. In some examples, the metal redox barrier 510 may be rotated while the substrate is being rinsed or during other normal electrodeposition system processes. This may help avoid downtime while rotating the metal redox barrier 510. Additionally, rotating the metal redox barrier 510 may not disturb the catholyte bath 524.

[0198] As discussed above with respect to Figure 3, in some examples, an ion exchange membrane may be used as the proton inhibiting structure. Figure 6A shows an example of an electrodeposition system 600 with an anion exchange membrane as the proton inhibiting structure. Electrodeposition system 600 may be an example of electrodeposition system 300. Briefly, electrodeposition system 600 includes an anode chamber 602 with an inert anode 604. Anode chamber 602 is configured to hold an anolyte reservoir 606, which may be replenished via an anolyte circulation loop 608.

[0199] An anion exchange membrane 610 separates an intermediate chamber 612 from the anode chamber 602. The intermediate chamber 612 may be configured to hold an intermediate reservoir 614. The intermediate reservoir 614 may be replenished via an intermediate reservoir circulation loop 616.

[0200] A cation exchange membrane 618 separates the intermediate chamber 612 from the cathode chamber 622. The cation exchange membrane 618 allows for selective transport of cations between the intermediate chamber 614 and the catholyte chamber 624. The cathode chamber 622 further includes a HRVA 626 and a substrate holder 628. A substrate 630 with a cathode layer may be placed in the substrate holder 628 and exposed to the catholyte chamber 624 during the electrodeposition process. The catholyte chamber 624 may be replenished via a catholyte circulation loop 632. A voltage source 634 may apply a voltage across the inert anode 604 and the substrate 630 to facilitate the electrodeposition process.

[0201] The electrodeposition system 600 is described with respect to a Cu plating process. However, in other examples, the electrodeposition system 600 may be used to perform any other suitable metal plating process. This example addresses the issue of mass balance imbalance that can arise from using an inert anode.

[0202] The anolyte reservoir 606 may contain a dilute acid (e.g., HSO). In some examples, the anolyte reservoir 606 may contain metal ions, but any metal ions contained therein are not used to provide metal ions to the plating substrate 630.

[0203] An anion exchange membrane 610 separates the anode chamber 602 from the intermediate chamber 612. The anion exchange membrane is a membrane that absorbs negatively charged species (e.g., SO4 2- ) may preferentially pass from the intermediate chamber 612 to the anode chamber 602. Additionally, electrolysis of water occurs at the inert anode 604, thereby generating H2SO4 inside the anode chamber. The cation exchange membrane 618 may preferentially pass positively charged species (e.g., protons and metal ions) across the membrane from the intermediate chamber 612 to the cathode chamber 622.

[0204] The intermediate bath 614 provides at least some of the metal ions for plating in the form of a metal salt. In the depicted example, the intermediate bath 614 contains the metal salt CuSO4. In other examples, any other suitable cations and / or anions may be used. The anion exchange membrane 610 and the cation exchange membrane 618 may be selected to be compatible with the selected ionic chemistry and / or may be conditioned with an appropriate solution prior to implementation.

[0205] The intermediate reservoir 614 and the catholyte reservoir 624 may contain the same chemical, for example, the same metal salt. In some examples, the intermediate reservoir 614 may contain a different concentration of the metal salt (e.g., copper sulfate) than the catholyte reservoir 624. In other examples, the intermediate reservoir 614 and the catholyte reservoir 624 may contain any suitable chemical difference.

[0206] A cation exchange membrane 618 is disposed between the cathode chamber 622 and the intermediate chamber 612 to allow Cu 2+ moves from intermediate chamber 612 to cathode chamber 622. In combination with the reduction reaction occurring at the surface of substrate 630, the catholyte Cu concentration may be maintained at a reasonably consistent level.

[0207] However, Cu from the intermediate chamber 612 through the cation exchange membrane 618 to the cathode chamber 622 2+ passes through the anion exchange membrane 610 to the anode chamber 602. 2- This, combined with the addition of CuSO4, depletes the CuSO4 in the intermediate chamber 612. Therefore, the intermediate chamber 612 may be replenished with CuSO4. Replenishment may be achieved, for example, by recirculating the intermediate chamber 614 with solid CuSO4 crystals via the intermediate chamber circulation loop 616 or by adding a concentrated salt solution.

[0208] The use of copper sulfate in the intermediate tank 614 may provide a cheaper source of copper ions than high-purity solid Cu active anodes. Furthermore, anode replacement is not required. Furthermore, supplying Cu ions through the solution may not generate particulate contaminants. In contrast, active anodes may generate particulate contaminants. Therefore, the use of copper sulfate intermediate tank 614 may enable the use of a simplified anolyte tank filtration system.

[0209] 2, the combined charge transfer effect of the cation exchange membrane 618 and the anion exchange membrane 610 may balance the mass balance of both metal ions and protons in the catholyte reservoir 624, which may lead to more stable catholyte reservoir concentrations. In this way, the mass balance of the catholyte reservoir 624 can be maintained without undue effort during the electrochemical plating process.

[0210] The cation exchange membrane 618 and the anion exchange membrane 610 may be replaced from time to time, although such maintenance may occur less frequently than replacement of the active anode.

[0211] 6B illustrates exemplary solution concentrations of copper ions and protons over time in the electrodeposition system 200 of FIG. 2 compared to the electrodeposition system 600 of FIG. 6A. At 650, the ion concentrations of each exemplary catholyte reservoir are shown over the operating time of the respective electrodeposition systems. At 660, the ion concentrations of each exemplary anolyte reservoir are shown over the operating time of the respective electrodeposition systems. At 670, the ion concentrations of an exemplary intermediate reservoir (e.g., intermediate reservoir 614) are shown.

[0212] In electrodeposition system 200, protons are continuously generated and accumulated in the anode chamber, as indicated at 660. Furthermore, the protons migrate across the cationic membrane to the cathode side. The net effect over time on the catholyte reservoir is a depletion of copper ions and an accumulation of acid, as indicated at 650. Concentration fluctuations can lead to problems in the plating process, such as defects. In contrast, in electrodeposition system 600, the buildup of acid in the anode chamber is buffered from the cathode chamber. Furthermore, the copper plated on the substrate is continuously replenished from an intermediate reservoir. Therefore, the combined use of both cationic and anionic membranes in an electrochemical plating system may balance the mass of acid ions and metal ions. Furthermore, the concentrations of both Cu ions and protons on the cathode side may be stable over time.

[0213] To further address proton generation and cell management, a redox shuttle system may be used in which a redox couple is used to avoid electrolysis of water in the anolyte. Figure 7 shows an example of an electrodeposition system 700 with an anion exchange membrane as the proton-inhibiting structure, a cation exchange membrane as the ion exchange membrane, and a redox shuttle circulation system configured to provide redox shuttle species to the anode chamber. Figure 8 shows a schematic of an example of a redox chemical reaction that may be used with electrodeposition system 700.

[0214] Briefly, electrodeposition system 700 is comprised of an anode chamber 702 with an inert anode 704. The anode chamber 702 is configured to hold an anolyte reservoir 706, which may be replenished via a redox shuttle circulation system 708. The electrodeposition system 700 further comprises an anion exchange membrane separating an intermediate chamber 712 from the anode chamber 702. The intermediate chamber 712 may be configured to hold an intermediate reservoir 714, which may be replenished via an intermediate reservoir circulation loop 716.

[0215] A cation exchange membrane 718 separates the intermediate chamber 712 from the cathode chamber 722. The cation exchange membrane 718 allows for selective transport of ions between the intermediate chamber 714 and the catholyte chamber 724. The cathode chamber 722 further includes a HRVA 726 and a substrate holder 728. A substrate 730 with a cathode layer may be placed in the substrate holder 728 and exposed to the catholyte chamber 724 during the electrodeposition process. The catholyte chamber 724 may be replenished via a catholyte circulation loop 732, which may include hardware features to control temperature, water balance, organic additive concentration, etc. A voltage source 734 may apply a voltage across the inert anode 704 and the substrate 730 to facilitate the electrodeposition process.

[0216] The redox shuttle circulation system 708 may be configured to provide redox shuttle species to the anode chamber 702. The redox shuttle circulation system 708 may further include a regeneration chamber 740 (e.g., a redox shuttle species regeneration chamber). The intermediate reservoir circulation loop 716 may include a plating metal ion source 742, such as a supply of concentrated copper sulfate for a copper plating reaction. In some examples, the intermediate chamber may be omitted. The anode chamber 702 may be separated from the cathode chamber 722 by a first ion exchange membrane, such as an anion exchange membrane 710.

[0217] With reference to Figure 8, an example of the operation and chemistry of the electrodeposition system 700 will be described in the context of copper plating. In this example, Fe 2+ / Fe 3+ ions may be added to the anolyte reservoir 706 as part of a redox shuttle. 2+ The oxidation potential of ferrous iron (Fe) is 700 mV lower than that of water. As a result, the oxidation reaction at the inert anode 704 is carried out by ferrous iron (Fe) while avoiding the formation of oxygen and protons. 2+ ) is oxidized to ferric iron (Fe 3+ ) to form the oxidized Fe 3+ The ions are transferred to the regenerative chamber 740, which is equipped with a source of electrons, such as a metal suitable for galvanic reaction, and then to the Fe 2+ The regenerated Fe may be individually reduced to 2+may be returned to the anode chamber 702 via the redox shuttle circulation system 708.

[0218] In other examples, any suitable redox couple other than iron may be used. Suitable redox couples include species in which the oxidation potential of the redox couple is lower than the oxidation potential during oxygen evolution. For example, the potential difference between the ferric iron reaction and the regenerating metal reaction may be at least 300 millivolts. When the total potential difference is positive, ΔG is positive and the shuttle reaction occurs spontaneously.

[0219] In the depicted example, Fe 3+ has a reduction potential of 0.77 V. Therefore, any metal or element with a positive oxidation potential or a reduction potential lower than 0.77 V may be used as a redox couple. Examples of such elements include copper, sulfur, lead, tin, nickel, cobalt, zinc, manganese, aluminum, and magnesium.

[0220] For regeneration of reduced ionic species, the regeneration chamber 740 may contain a metal or other electron donor capable of undergoing a suitable galvanic reaction. In the example shown in FIG. 8, iron metal 802 is used. Note that the metal used for regeneration may be different from the metal used for plating. However, in some examples, a plating metal (e.g., copper) may be used for regeneration. In some examples, the regeneration chamber 740 includes an oxygen removal stage 744.

[0221] In this configuration, three chambers of the electrodeposition system 700 are created by placing an anion exchange membrane 710 between the anode chamber 702 and the intermediate chamber 712, and a cation exchange membrane 718 between the intermediate chamber 712 and the cathode chamber 722. The anolyte reservoir 706 contains ferrous sulfate, as shown at 800 in Figure 8. In this example, copper sulfate is contained in the intermediate reservoir 714, and a low-acid solution is contained in the catholyte reservoir 724 (e.g., a mixture containing copper sulfate, sulfuric acid, and chloride).

[0222] Because little acid is generated at the inert anode 704, no associated increase in acid concentration occurs over time in either the intermediate chamber 714 or the catholyte chamber 724. The majority of the charge is carried by copper ions from the intermediate chamber 712 to the catholyte chamber 722, thereby replenishing the plated copper and maintaining the copper concentration in the catholyte chamber 724. Although described with respect to copper, a redox shuttle may be used to avoid acid generation in any other suitable electrodeposition process.

[0223] As mentioned above, the use of inert anodes can reduce preventative maintenance costs compared to using consumable anodes. Plating may thus be carried out at increased currents without causing anode passivation. Furthermore, little or no acid is generated in the anolyte chamber, simplifying cell management. Gas bubble generation is kept low and does not interfere with the electrical path. Plating uniformity can be maintained because a membrane is used to isolate and contain the solution.

[0224] Over time, the concentration of the regenerating species may increase within the redox shuttle circulation system 708. For example, copper metal may accumulate as copper sulfate over time. As another example, iron may accumulate as ferrous sulfate. In some instances, dissolved regenerating species (e.g., Cu 2+ Additional species of metals may also be included to galvanically extract ) from the anodic solution. With some regenerative species, such as iron, some hydrogen may be evolved into solution, allowing for control of the acid concentration in the regenerative chamber 740 without leading to gas bubbles in the anode chamber itself.

[0225] In some examples, the oxygen concentration in the anode chamber may be regulated to prevent the formation of metal oxide precipitates (e.g., ferrous oxide) within the anode chamber 702. In some such examples, the anode chamber 702 may be backfilled with an inert gas to reduce the dissolved oxygen concentration throughout the electrodeposition system 700. The regeneration chamber 740 may optionally include an oxygen removal stage 744 for removing oxygen from the system.

[0226] Over time, iron ions dissolve from metallic iron 802 into anolyte reservoir 706. Additionally, copper ions are plated onto substrate 730 from catholyte reservoir 724. However, because anion exchange membrane 710 separates anode chamber 702 and intermediate chamber 712, iron ions from metallic iron 802 do not enter intermediate chamber 712 or cathode chamber 722. Rather, copper to be plated is provided from intermediate chamber 712 via plating metal ion source 742.

[0227] The conductivity throughout the electrodeposition system 700 increases only slightly over time due to minimal acid formation at the inert anode 704. Any increase in conductivity can be attributed in large part to an increase in metal ion concentration from the redox shuttle circulation system 708.

[0228] Figure 9A shows an electrodeposition system 900 that utilizes an alternative approach to address the mass balance imbalance problem of utilizing an inert anode. Figure 9A also employs a three-chamber design. However, instead of utilizing an anion exchange membrane between the anode chamber and the middle chamber and a cation exchange membrane between the middle chamber and the cathode chamber, electrodeposition system 900 utilizes two layers of anion exchange membranes.

[0229] More specifically, electrodeposition system 900 includes an anode chamber 902 with an inert anode 904. Anode chamber 902 is configured to hold an anolyte reservoir 906 that can be replenished via a circulation loop 908 (e.g., an anolyte circulation loop).

[0230] A first anion exchange membrane 910 may separate the intermediate chamber 912 from the anode chamber 902. The intermediate chamber 912 may be configured to hold an intermediate reservoir 914, which may be replenished via an intermediate reservoir circulation loop 916. A second anion exchange membrane 918 separates the intermediate chamber 912 from the cathode chamber 922, allowing selective transport of ions between the intermediate reservoir 914 and the catholyte reservoir 924. The cathode chamber 922 further includes an HRVA 926 and a substrate holder 928. A substrate 930 with a cathode layer may be disposed in the substrate holder 928 and exposed to the catholyte reservoir 924 during the electrodeposition process. The catholyte reservoir 924 may be replenished via a catholyte circulation loop 932. A voltage source 934 may apply a voltage across the inert anode 904 and the substrate 930 to facilitate the electrodeposition process.

[0231] Compared to the example of FIG. 6A, the electrodeposition system of FIG. 9A can maintain a more consistent acid concentration in the bath. This is at least because the anion exchange membrane material can allow a certain amount of protons to pass through, even though the preferred charge transfer species is anion. By adding a second anion exchange membrane 918 between the inert anode 904 and the substrate 930, the direct transfer of protons from the proton-rich anode chamber 902 to the cathode chamber 922 is mitigated. Instead, the protons are transported into the intermediate chamber 912. When charge is transported across the second anion exchange membrane 918 between the intermediate chamber 912 and the cathode chamber 922, SO4 is preferred over protons. 2- This selective preference helps limit the number of protons that enter the cathode chamber 922 and maintains the acid balance of the catholyte reservoir 924.

[0232] Water is heated in the anode chamber 902 by H +and O2, and copper is reduced onto the substrate 930. Sulfate migrates across the first anion exchange membrane 910 into the anode chamber 902. Copper migrates from the intermediate chamber 912 across the second anion exchange membrane 918 to the cathode chamber 922, completing the electrical circuit. As hydrogen is generated, sulfate enters the anode chamber 902 as a form of charge balance and to reduce transfer pressure. The sulfuric acid concentration increases over time, retaining protons as sulfuric acid in the anode chamber 902. This acidification may be countered by water administration via the anolyte reservoir circulation loop 908 to maintain the acid concentration at a desired level. Plated copper from the catholyte reservoir 924 is replenished from the intermediate chamber 912 across the second anion exchange membrane 918.

[0233] Copper sulfate may be depleted from the intermediate chamber 912. Therefore, copper sulfate may be replenished via the intermediate reservoir circulation loop 916. Regardless of the membrane selectivity, some amount of protons will migrate from the anode chamber 902. Acid balance may be maintained by providing an adequate and consistent supply of copper sulfate to the intermediate chamber 912. If the pH of the intermediate reservoir 914 is kept sufficiently low and water is introduced into the anolyte reservoir circulation loop 908, proton migration may be maintained at an adequately low level.

[0234] 9B illustrates exemplary solution concentrations of copper ions and protons over time in the electrodeposition system 200 of FIG. 2 compared to the electrodeposition system 900 of FIG. 9A. At 950, exemplary ion concentrations in each catholyte reservoir are shown over the operating time of the respective electrodeposition tools. At 960, exemplary ion concentrations in each anolyte reservoir are shown over the operating time of the respective electrodeposition tools. At 970, exemplary ion concentrations in intermediate reservoirs (e.g., intermediate reservoir 914) are shown.

[0235] Once steady state is reached, all three baths exhibit stable concentrations. Plating operations may therefore begin as soon as the copper concentration in the cathode chamber is within the desired concentration range. Even at time zero, sufficient copper may be present for the plating reaction if the acid concentration is within the desired range. As shown in 950 and 960, the proton concentration in the catholyte bath remains relatively low and constant, even as more acid is generated at the anode.

[0236] 10 shows an example of an electrodeposition system 1000 with a cation exchange membrane as the proton inhibition structure and a cation exchange membrane as the ion exchange membrane. The electrodeposition system 1000 may be an example of the electrodeposition system 300. Briefly, the electrodeposition system 1000 includes an anode chamber 1002 with an inert anode 1004. The anode chamber 1002 is configured to hold an anolyte reservoir 1006 that can be replenished via an anolyte circulation loop 1008.

[0237] A first cation exchange membrane 1010 may separate an intermediate chamber 1012 from the anode chamber 1002. The intermediate chamber 1012 may be configured to hold an intermediate reservoir 1014. The intermediate reservoir 1014 may be replenished via an intermediate reservoir circulation loop 1016.

[0238] A second cation exchange membrane 1018 may separate the intermediate chamber 1012 from the cathode chamber 1022. The second cation exchange membrane 1018 allows for selective transport of ions between the intermediate chamber 1014 and the catholyte chamber 1024. The cathode chamber 1022 further includes an HRVA 1026 and a substrate holder 1028. A substrate 1030 with a cathode layer may be placed in the substrate holder 1028 and exposed to the catholyte chamber 1024 during the electrodeposition process. The catholyte chamber 1024 may be replenished via a catholyte circulation loop 1032. A voltage source 1034 may apply a voltage across the inert anode 1004 and the substrate 1030 to facilitate the electrodeposition process.

[0239] At the inert anode 1004, protons are generated and transported across a first cation exchange membrane 1010 into an intermediate chamber 1014. In this example, the intermediate chamber circulation loop 1016 includes a copper oxide module 1040. CuSO4 and H2SO4 exit the intermediate chamber 1012. Protons from H2SO4 react with Cu in the copper oxide module 1040 to form Cu 2+ and HO. In this manner, the protons transported into the intermediate chamber 1014 are exchanged for copper, replenishing the copper that migrates across the second cation exchange membrane 1018 into the catholyte chamber 1024. This can help provide an appropriately stable concentration of copper in the catholyte chamber 1024. In some examples, the anolyte circulation loop 1008 may administer a less acidic solution to the anolyte chamber 1006 to further manage the acid generated by the inert anode 1004. In some examples, the intermediate chamber may be omitted. The anode chamber 1002 may be separated from the cathode chamber 1022 by a single cation exchange membrane, for example, the second cation exchange membrane 1018, such that the copper oxide module 1040 is fluidly coupled to the anode chamber 1002.

[0240] In another example, the issues of mass balance and catholyte acidification may be addressed by using an anion exchange membrane. FIG. 11A shows an example of an electrodeposition system 1100 that includes an anion exchange membrane but no cation exchange membrane or other proton-inhibiting structure. Briefly, the electrodeposition system 1100 includes an anode chamber 1102 with an inert anode 1104. The anode chamber 1102 is configured to hold an anolyte reservoir 1106 that can be replenished via an anolyte circulation loop 1108. The electrodeposition system 1100 is similar in structure to the electrodeposition system 200, but replaces the cation exchange membrane 206 with an anion exchange membrane 1118.

[0241] An anion exchange membrane 1118 separates the anode chamber 1102 from the cathode chamber 1122. The anion exchange membrane 1118 allows for selective transport of ions between the anolyte reservoir 1106 and the catholyte reservoir 1124. The cathode chamber 1122 further includes an HRVA 1126 and a substrate holder 1128. A substrate 1130 with a cathode layer may be placed in the substrate holder 1128 and exposed to the catholyte reservoir 1124 during the electrodeposition process. The catholyte reservoir 1124 may be replenished via a catholyte circulation loop 1132. A voltage source 1134 may apply a voltage across the inert anode 604 and the substrate 630 to facilitate the electrodeposition process.

[0242] As shown, protons generated at the inert anode 1104 can cross the anion exchange membrane 1118 and enter the cathode chamber 1122, but at a relatively slow rate. Sulfate from the catholyte reservoir 1124 crosses the anion exchange membrane 1118 and forms H2SO4 in the anolyte reservoir 1106. Copper is maintained in the cathode chamber 1122 by the anion exchange membrane 1118 and can be replenished with copper sulfate via the catholyte circulation loop 1132.

[0243] The net effect of the above process on solution concentrations is shown in FIG. 11B , which illustrates exemplary solution concentrations of copper ions and protons over time in the electrodeposition system 200 of FIG. 2 compared to the electrodeposition system 1100 of FIG. 11A . At 1150, exemplary ion concentrations in each catholyte reservoir are shown over the operating time of the respective electrodeposition tools. At 1160, exemplary ion concentrations in each anolyte reservoir are shown over the operating time of the respective electrodeposition tools. As illustrated, the use of anion exchange membranes can provide more consistent ion concentrations compared to the use of cation exchange membranes. Notably, in anion exchange membrane-based electrodeposition systems, the ion concentrations in the catholyte reservoirs stabilize relatively quickly, as shown at 1150.

[0244] 12 is a flow diagram illustrating an exemplary method 1200 for forming a layer of a selected metallic material on a substrate by electrodeposition. Method 1200 may be performed by a controller, such as computing system 150, communicatively coupled to an electrodeposition system, such as electrodeposition system 300.

[0245] At 1210, method 1200 includes introducing catholyte into a cathode chamber, for example, by a catholyte circulation loop. The catholyte may include at least a supply of metal ions for electrodeposition on a substrate. At 1220, method 1200 includes introducing anolyte into an anode chamber with an inert anode, for example, by an anolyte circulation loop. As described with respect to FIGS. 4 and 5, the anolyte may include metal ions for electrodeposition on a substrate. Alternatively, as described with respect to FIGS. 9A and 10, the anolyte may include a dilute acid solution with counterions selected based on the overall chemistry of the electrodeposition system.

[0246] At 1230, the method 1200 includes introducing the solution into an intermediate chamber located between the cathode chamber and the anode chamber, the intermediate chamber being separated from the anode chamber by a proton-inhibiting structure and separated from the cathode chamber by an ion-exchange membrane. The solution introduced into the intermediate chamber (e.g., intermediate tank) may be introduced by an intermediate tank circulation loop, which in some examples may be fluidly coupled to a source of plating metal ions.

[0247] In some examples, the proton inhibiting structure comprises a metal barrier with a selected metal, as described with respect to Figures 4 and 5. The proton inhibiting structure may alternatively comprise an anion exchange membrane, as described with respect to Figures 7, 8, and 9A, or a cation exchange membrane, as described with respect to Figures 6A and 10.

[0248] At 1240, the method 1200 includes exposing the substrate to the catholyte, for example, by placing the substrate holder in a cathode chamber. At 1250, the method 1200 includes reducing ions of the selected metal in the catholyte onto the substrate by applying a voltage across the cathode and an inert anode.

[0249] At 1260, method 1200 includes inhibiting the flow of acidic species from the anode chamber to the cathode chamber with a proton-inhibiting structure. If the proton-inhibiting structure comprises a metal barrier containing a selected metal, the method may include depositing a film of the selected metal on the anode side of the metal redox barrier by reducing ions of the selected metal from the anolyte. Such examples may further include forming ions of the selected metal in the intermediate chamber by oxidizing the cathode side of the metal redox barrier. In some such examples, the method may further include biasing the metal redox barrier toward the intermediate chamber. The ions of the selected metal in the intermediate chamber pass through the ion exchange membrane to the cathode chamber.

[0250] In an example where the proton-inhibiting structure comprises an anion exchange membrane, the ion exchange membrane separating the intermediate chamber and the cathode chamber may be comprised of a cation exchange membrane. In such an example, the method may further comprise flowing an intermediate chamber solution through the intermediate chamber, the intermediate chamber solution comprising a salt of the selected metal.

[0251] In some examples, the proton-inhibiting structure comprises a cation exchange membrane, and the ion exchange membrane separating the intermediate chamber and the cathode chamber comprises a cation exchange membrane. In such examples, the method may further include flowing an intermediate chamber solution through the intermediate chamber, the intermediate chamber solution comprising a salt of the selected metal.

[0252] In some examples, the proton-inhibiting structure comprises an ion exchange membrane. In such examples, the electrodeposition system may further comprise a redox shuttle circulation system configured to provide the redox shuttle species in the anolyte to the anode chamber. In such examples, the method may further include flowing the anolyte through the redox shuttle species regeneration chamber.

[0253] Also disclosed are examples related to bubble management in electrodeposition systems. Briefly, the disclosed examples utilize an inert anode assembly having an anolyte flow channel configured to flow anolyte at a linear flow rate sufficient to reduce bubble buildup below an ion exchange membrane. As described in more detail below, the disclosed exemplary inert anode assembly may be more compact than conventional anode chambers in electrodeposition systems. Furthermore, the disclosed exemplary inert anode assembly may also facilitate a reduced anolyte flow volume compared to conventional anode chambers.

[0254] 13 shows a schematic block diagram of another exemplary electrodeposition system 1300. The electrodeposition system 1300 consists of an electrodeposition cell 1302 with a cathode chamber 1304. The cathode chamber 1304 holds a catholyte. The catholyte contains ionic species that are deposited onto a cathode layer of a substrate 1306 as a metal by electrochemical reduction.

[0255] The electrodeposition cell 1302 further comprises an inert anode assembly 1308. The inert anode assembly 1308 comprises an inert anode 1310 and an anolyte channel component 1312. Anolyte flow channels formed in the anolyte channel component 1312 confine anolyte flow to segmented regions during the electrodeposition process.

[0256] An ion exchange membrane 1314 is disposed between the cathode chamber bottom component 1316 and the anolyte channel component 1312. In various examples, the ion exchange membrane 1314 may comprise a cation exchange membrane or an anion exchange membrane. The electrodeposition system 1300 further comprises a high resistance virtual anode (HRVA) 1318 within the cathode chamber 1304. The HRVA 1318 comprises an ionic resistance element in proximity to a suitably constant and uniform current source in proximity to the substrate cathode.

[0257] The substrate holder 1320 exposes the substrate 1306 to the catholyte during the electrodeposition process. Furthermore, the substrate holder 1320 is coupled to a substrate holder movement system 1322. The substrate holder movement system 1322 includes a lift 1324 configured to adjust the position of the substrate holder 1320. For example, the lift 1324 lowers the substrate holder 1320 to position the substrate 1306 in the catholyte for electrodeposition. The lift 1324 also raises the substrate holder 1320 from the catholyte after electrodeposition. The substrate holder movement system 1322 further includes components for controlling the opening and closing of the substrate holder 1320.

[0258] Catholyte may be circulated between the cathode chamber 1304 and the catholyte reservoir 1326 using a combination of gravity and one or more pumps 1328. Similarly, anolyte is circulated through the anolyte reservoir 1330 and the anolyte flow channels of the anolyte channel component 1312 using a combination of gravity and one or more pumps 1332. Bulk anolyte and / or catholyte solution may be added to replenish and / or rebalance ionic species.

[0259] Some electrodeposition systems may use multiple plating cells to perform plating operations on multiple substrates in parallel. In some such examples, a central catholyte and / or anolyte reservoir may supply catholyte and / or anolyte to multiple plating cells. In other such examples, separate catholyte and / or anolyte reservoirs may be used to supply multiple plating cells. In still other examples, the electrodeposition system may include a single plating cell. When an electrodeposition system includes multiple plating cells, a single lift may be configured to lift two or more substrate holders for two or more different plating cells.

[0260] After the substrate 1306 is loaded into the substrate holder 1320, the substrate holder 1320 is lowered toward the HRVA 1318 by a lift 1324. The substrate 1306 faces the surface of the HRVA 1318 and is separated from the HRVA 1318 by a plating gap during electrodeposition. An electric field is established between the inert anode 1310 and the substrate 1306. This electric field drives dissolved metal cations toward the substrate 1306, where they are electrochemically reduced, depositing a metal film on the substrate 1306. An anodic potential is applied to the inert anode 1310 using an anode electrical connection 1334, and a cathodic potential is applied to the cathode of the substrate 1306 using a cathode electrical connection 1336, completing a circuit. In some examples, the substrate holder 1320 may be rotated during electrodeposition using a rotation motor 1338.

[0261] The electrodeposition system 1300 further comprises a computing system 1340. Aspects of the computing system 1340 are described in further detail below with respect to FIG. 30 . The computing system 1340 may include executable instructions 1342 to control any suitable function of the electrodeposition system 1300. Exemplary functions include the electrodeposition process and the substrate loading / unloading process. In some examples, the computing system 1340 may be configured to communicate with a remote computing system 1344 using a suitable computer network. The remote computing system 1344 may comprise any suitable computing system. Examples include a networked workstation computer, an enterprise computing system, and / or a cloud computing system. It will be understood that the remote computing system 1344 may communicate with and control multiple electrodeposition systems in some examples.

[0262] As described above, the anolyte flow channel can be used to generate a linear anolyte flow rate sufficient to prevent the accumulation of air bubbles below the ion exchange membrane. FIG. 14 schematically illustrates a top view of an exemplary inert anode assembly 1400. FIG. 15 illustrates an exploded view of the inert anode assembly 1400. The inert anode assembly 1400 is an example of the inert anode assembly 1308. The inert anode assembly 1400 includes a first inert anode 1402 and a second inert anode 1404. The first inert anode 1402 is electrically coupled to an anode potential. In some examples, the first inert anode 1402 can be electrically connected to an anode potential using a metal screw that secures the first inert anode 1402. In other examples, the first inert anode 1402 can be electrically connected to an electrical pad adjacent to the first inert anode 1402. Similarly, the second inert anode 1404 is electrically coupled to an anode potential. In some examples, the first and second inert anodes 1402, 1404 are connected to the same anode potential. In other examples, the first and second inert anodes 1402, 1404 are connected to separate anode potentials.

[0263] The inert anode assembly 1400 further comprises a first anolyte flow channel 1406. The first anolyte flow channel 1406 defines a first segmented region of anolyte flow across the first inert anode 1402. The first segmented region of anolyte flow enters the first anolyte flow channel 1406 at a first inlet 1408 and exits through a first outlet 1410. The first anolyte flow channel 1406 is at least partially defined by an anolyte channel component 1412, as shown in FIG. 15 . Similarly, a second anolyte flow channel 1414 defines a second segmented region of anolyte flow across the second inert anode 1404. Anolyte enters the second anolyte flow channel 1414 at a second inlet 1416 and exits through a second outlet 1418. In some examples, the anolyte in the first anolyte flow channel 1406 may flow in the opposite direction to the anolyte in the second anolyte flow channel 1414. In other examples, the anolyte in the first anolyte flow channel 1406 and the anolyte in the second anolyte flow channel 1414 may flow in the same direction.

[0264] The inert anode assembly 1400 further includes a cathode chamber bottom piece 1420. The cathode chamber bottom piece 1420 is configured to define the bottom of a cathode chamber in an electrodeposition cell of an electrodeposition system. The cathode chamber bottom piece 1420 includes a first opening 1422 and a second opening 1424. The first opening 1422 allows ionic current to flow between the catholyte in the first opening 1422 and the anolyte in the first anolyte flow channel 1406. Similarly, the second opening 1424 allows ionic current to flow between the anolyte in the second opening 1422 and the anolyte in the second anolyte flow channel 1414.

[0265] The inert anode assembly further comprises an ion exchange membrane 1500 (not shown in FIG. 14 for clarity). The ion exchange membrane 1500 is disposed between the cathode chamber bottom part 1420 and the anolyte channel part 1412. By disposing the ion exchange membrane 1500 between the cathode chamber bottom part 1420 and the anolyte channel part 1412, the area of the ion exchange membrane 1500 exposed to the catholyte and anolyte is reduced compared to electrodeposition systems that omit the anolyte flow channels as disclosed. This helps reduce deformation of the ion exchange membrane 1500 that can trap gas bubbles.

[0266] In some examples, the ion exchange membrane 1500 comprises a cation exchange membrane. In such examples, cations generated at the first and second inert anodes 1402, 1404 flow through the ion exchange membrane 1500 into the catholyte in the first and second openings 1422, 1424 of the cathode chamber bottom component 1420. For example, in some exemplary processes, water is oxidized at the first and second inert anodes 1402, 1404. In such examples, protons flow through the ion exchange membrane 1400. In such examples, deposition metal ions may be added to the catholyte or anolyte for supplementation.

[0267] In other examples, ion exchange membrane 1500 comprises an anion exchange membrane. In such examples, during the electrodeposition process, anions in the catholyte flow through ion exchange membrane 1400 toward first anolyte flow channel 1406 and second anolyte flow channel 1414. As a more specific example, if the catholyte contains copper for depositing a copper film, sulfate anions may pass through ion exchange membrane 1500. In such examples, deposition metal ions may be added to the catholyte for supplemental use.

[0268] In the depicted example, the inert anode assembly 1400 includes two parallel anolyte flow channels. The first anolyte flow channel 1406 and the second anolyte flow channel 1414 may be fluidly connected in parallel or in series. In other examples, the inert anode assembly may include other suitable numbers and arrangements of anolyte flow channels. The number and configuration of the anolyte flow channels may be selected based on various factors. For example, the number and configuration of the anolyte flow channels may be selected to achieve a desired ionic current uniformity between the inert anode and the cathode. The number and configuration of the anolyte flow channels may alternatively or additionally be based on a desired linear flow rate through the anolyte flow channels in terms of a pumping system used to circulate the anolyte. In addition to linear anolyte flow channels, other exemplary configurations include concentrically arranged anolyte flow channels.

[0269] FIG. 16 schematically illustrates a cross-sectional view of the inert anode assembly 1400 taken along line 16-16 in FIG. 14. As shown, an ion exchange membrane 1500 is disposed between the cathode chamber bottom component 1420 and the anolyte channel component 1412. As shown, a first anolyte flow channel 1406 directs anolyte flow across the first inert anode 1402, as indicated at 1602. The first anolyte flow channel 1406 is configured to provide a linear flow velocity sufficient to prevent the accumulation of air bubbles below the ion exchange membrane 1500. In some examples, the first anolyte flow channel 1406 may be configured to provide a linear flow velocity in the range of 0.1 to 10 meters per second. The anolyte flow enters the circulation loop from the first anolyte flow channel 1406 to an anolyte reservoir 1604 and a pump 1606. The gas bubbles may be exhausted from the anolyte in the anolyte reservoir 1604 or from any other suitable point along the circulation loop. A controller 1608 controls the flow rate produced by the pump 1606. The flow rate may be selected to produce a desired linear flow rate through the first anolyte flow channel 1606. A second anolyte flow channel 1414 (not shown in FIG. 16) functions similarly to the first anolyte flow channel 1406.

[0270] The depicted inert anode assembly 1400 may be more compact than conventional anode chambers used in electrodeposition tools, at least because the first anolyte flow channel 1406 and the second anolyte flow channel 1414 may occupy less space than the rest of the anode chamber. Furthermore, the inert anode assembly 1400 may be used to reduce the anolyte volume compared to conventional anode chambers, again due to the smaller volumes of at least the first anolyte flow channel 1406 and the second anolyte flow channel 1414.

[0271] The anolyte channel component 1412 and the cathode chamber bottom component 1420 may be clamped or otherwise held together when installed in the electroplating tool. In some examples, multiple fasteners, such as screws, may be used to fasten the anolyte channel component 1412 and the cathode chamber bottom component 1420 together. In other examples, the anolyte channel component 1412 and the cathode chamber bottom component 1420 may be joined together in any other suitable manner. One or more sealing components may be used to prevent leakage of the anolyte. Examples include one or more O-rings arranged between the anolyte channel component 1412 and the cathode chamber bottom component 1420.

[0272] In the examples of Figures 14-16, each anolyte flow channel is associated with a corresponding inert anode. In other examples, the inert anode may comprise a shared inert anode shared between two or more anolyte flow channels. Figure 17 schematically illustrates an exemplary inert anode assembly 1700 having a shared inert anode 1702. The inert anode assembly 1700 is an example of the inert anode assembly 1308. A first anolyte flow channel 1704 defines a first segmented region of anolyte flow across the shared inert anode 1702. Additionally, a second anolyte flow channel 1706 defines a second segmented region of anolyte flow across the shared inert anode 1702.

[0273] The inert anode assembly 1700 further comprises a cathode chamber bottom piece 1708 having a first opening 1710 and a second opening 1712. The first opening 1710 is disposed opposite the first anolyte flow channel 1704. The first opening 1710 allows ionic current to flow between the catholyte in the first opening 1710 and the anolyte in the first anolyte flow channel 1704 during the electrodeposition process. Similarly, the second opening 1712 is disposed opposite the second anolyte flow channel 1706. The inert anode assembly 1700 further comprises an ion exchange membrane (not shown) disposed between the cathode chamber bottom piece 1708 and the anolyte channel piece 1714. In other examples, the inert anode assembly 1700 can comprise any other suitable number and / or configuration of anolyte flow channels and / or openings in the cathode chamber bottom piece 1708.

[0274] As discussed above, the anolyte flow channel can be configured to generate a linear flow velocity sufficient to prevent the accumulation of air bubbles below the ion exchange membrane. In the examples described above, the disclosed inert anode assembly includes multiple analyte flow channels. In other examples, a single anolyte flow channel, as opposed to multiple anolyte flow channels, may vary in direction along its length to cover a larger area. In all of these examples, the width of the anolyte flow channel is shorter than the length of the anolyte flow channel to achieve a linear flow velocity across the width of the anolyte flow channel.

[0275] 18 schematically illustrates an exemplary inert anode assembly 1800 with a spiral-path anolyte flow channel 1802. The inert anode assembly 1800 is an example of the inert anode assembly 1308. The anolyte flow channel 1802 defines a region of anolyte flow across the inert anode 1804. As shown, the anolyte flow channel 1802 is configured with a width that is less than its length.

[0276] The inert anode assembly 1800 further comprises a cathode chamber bottom piece 1806 having an opening 1808. The opening 1808 is disposed opposite the anolyte flow channel 1802. In the depicted example, the opening 1808 has the same helical path as the anolyte flow channel 1802. In other examples, the opening 1808 can have a different configuration than the anolyte flow channel 1802. The opening 1808 allows ionic current to flow between the catholyte in the opening 1808 and the anolyte in the anolyte flow channel 1802 during the electrodeposition process. The inert anode assembly 1800 further comprises an ion exchange membrane (not shown) disposed between the cathode chamber bottom piece 1806 and the anolyte channel piece 1810.

[0277] 19 shows another exemplary inert anode assembly 1900 with an anolyte flow channel 1902 that changes direction. In this example, the anolyte flow channel 1902 has a serpentine path. The inert anode assembly 1900 is an example of the inert anode assembly 1308. The anolyte flow channel 1902 defines a region of anolyte flow across the inert anode 1904. As shown, the anolyte flow channel 1902 is comprised of a length and a width, where the width is less than the length.

[0278] The inert anode assembly 1900 further comprises a cathode chamber bottom piece 1906 having an opening 1908. The opening 1908 is disposed opposite the anolyte flow channel 1902. In the depicted example, the opening 1908 has the same serpentine path as the anolyte flow channel 1902. In other examples, the opening 1908 can have a different configuration than the anolyte flow channel 1902. The opening 1908 allows ionic current to flow between the catholyte in the opening 1908 and the anolyte in the anolyte flow channel 1902 during the electrodeposition process. The inert anode assembly 1900 further comprises an ion exchange membrane (not shown) disposed between the cathode chamber bottom piece 1906 and the anolyte channel piece 1910.

[0279] As ions flow between the anolyte flow channel and the cathode chamber, their concentrations can change in the anolyte and / or catholyte. For example, if the ion exchange membrane comprises a cation exchange membrane, protons migrate from the anolyte to the catholyte. This can increase the acidity of the catholyte over time, requiring periodic intervention to maintain the desired pH. Therefore, to help reduce the flow of protons into the cathode chamber, the electrodeposition system may use an intermediate channel component defining one or more intermediate flow channels through which an intermediate electrolyte flows. In some examples, the one or more intermediate flow channels may be separated from the anolyte flow channel by an anion exchange membrane and from the cathode chamber by a cation exchange membrane. The intermediate electrolyte may contain a metal salt composed of the metal ions to be electrodeposited. As protons are generated in the anolyte at the inert anode, anions in the intermediate solution can migrate across the anion exchange membrane to the anolyte flow channel where the inert anode is located to balance the charge. Similarly, metal ions migrate across the cation exchange membrane into the cathode chamber and are subjected to electrochemical reduction. In this way, the pH in the cathode chamber can be more easily maintained. One example of a metal salt that can be included in the intermediate electrolyte is copper sulfate.

[0280] 20 schematically illustrates an exemplary inert anode assembly 2000 including an intermediate channel piece 2002. The inert anode assembly 2000 is an example of the inert anode assembly 1308. The intermediate channel piece 2002 at least partially defines an intermediate flow channel 2004. As described above, the intermediate flow channel 2004 is configured to support the flow of an intermediate electrolyte. The intermediate electrolyte may include a metal salt to provide metal ions to the catholyte and anions to the anolyte.

[0281] Intermediate channel component 2002 is disposed between cathode chamber bottom component 2006 and anolyte channel component 2008. Intermediate electrolyte flows in a circulation loop through intermediate flow channel 2004, electrolyte reservoir 2010, and pump 2012. Instantaneous electrolyte may be replenished in electrolyte reservoir 2010. Controller 2014 controls the flow rate produced by pump 2012. Thus, controller 2014 can control the linear flow rate of intermediate electrolyte through intermediate flow channel 2004.

[0282] Opening 2016 of intermediate flow channel 2004 is positioned opposite anolyte flow channel 2018. Opening 2016 therefore allows anions from the intermediate electrolyte in intermediate flow channel 2004 to migrate across anion exchange membrane 2020 to the anolyte in anolyte flow channel 2018.

[0283] Anolyte flow enters the circulation loop from anolyte flow channel 2018 to anolyte reservoir 2022 and pump 2024. Controller 2014 controls pump 2024, which in turn controls the linear flow rate across inert anode 2026. Anolyte flow channel 2018 may be configured to produce a linear flow rate sufficient to prevent the accumulation of air bubbles below anion exchange membrane 2020. Additionally, middle channel piece 2002 prevents air bubbles from migrating to cation exchange membrane 2030 between middle channel piece 2002 and cathode chamber bottom piece 2006. This may further help prevent air bubbles from affecting plating uniformity.

[0284] The opening 2016 of the intermediate flow channel 2004 is also positioned opposite the opening 2028 of the cathode chamber bottom piece 2006. This configuration allows cations from the intermediate electrolyte in the intermediate flow channel 2004 to migrate across the cation exchange membrane 2030 to the catholyte in the opening 2028 of the cathode chamber bottom piece 2006 during the electrodeposition process.

[0285] Although the intermediate channel piece 2002 is shown with a single intermediate flow channel, the inert anode assembly 2000 may include any other suitable number of intermediate flow channels between the anolyte flow channel and the opening in the cathode chamber. Additionally, the inert anode assembly 2000 may include any suitable number of additional intermediate channel pieces and associated ion exchange membranes.

[0286] As previously mentioned, an inert anode assembly according to the present disclosure can help reduce the accumulation of air bubbles on an ion exchange membrane in an electrodeposition system. Figure 21 is a flow diagram of an exemplary method 2100 for operating an electrodeposition system. Method 2100 may be performed on any suitable electrodeposition system equipped with an inert anode assembly. Examples include electrodeposition system 1300 and inert anode assemblies 1400, 1700, 1800, 1900, and 2000.

[0287] Method 2100 includes, at 2102, placing a substrate in a cathode chamber of an electrodeposition system. Method 2100 further includes, at 2104, exposing the substrate to a catholyte in the cathode chamber. The catholyte includes metal ions for electrodeposition on the substrate. Subsequently, method 2100 includes, at 2106, generating cations and gas bubbles in the anolyte at an inert anode of an inert anode assembly during the electrodeposition process. In some examples, the anolyte includes an aqueous solution. As such, the cations may include hydrogen cations, and the gas bubbles may include oxygen molecules generated by oxidation of water molecules. The cations and gas bubbles may be generated in a first anolyte flow channel at a first inert anode and in a second anolyte flow channel at a second inert anode, as shown at 2108. Alternatively or additionally, the cations and gas bubbles may be generated at a shared inert anode shared between the anolyte flow channels, as shown at 2110.

[0288] Next, method 2100 includes, at 2112, flowing the anolyte at a linear flow rate sufficient to prevent at least some gas bubbles from accumulating on an ion exchange membrane between the anolyte flow channel and the catholyte. Such a configuration may help remove gas bubbles while in suspension. In such a manner, gas bubbles may not coalesce into larger bubbles and interfere with electrodeposition. Furthermore, the linear flow rate across the inert anode may help increase mass transfer in the catholyte. In some examples, flowing the anolyte at a sufficient linear flow rate includes flowing the anolyte at a linear flow rate in the range of 0.1 to 10 meters per second, as shown at 2114. In some examples, method 2100 includes, at 2116, restricting the anolyte flow to segmented regions using two or more anolyte flow channels formed in the anolyte channel component of the inert anode assembly. Such a configuration may help reduce the volume of anolyte used in the electrodeposition system compared to a conventional anode chamber.

[0289] As described above, some inert anode assemblies include an intermediate flow channel through which the intermediate electrolyte flows. The intermediate flow channel may be separated from the anolyte flow channel by an anion exchange membrane. The intermediate flow channel may further be separated from the cathode chamber by a cation exchange membrane. Thus, in some examples, method 2100 includes, at 2118, flowing the intermediate electrolyte through the intermediate flow channel between the anolyte flow channel and the cathode chamber. The use of the intermediate flow channel, as described above, helps maintain a desired pH of the catholyte during electrodeposition.

[0290] Thus, use of the inert anode assemblies described herein can help reduce or prevent the accumulation of gas bubbles on the ion exchange membrane in electrodeposition systems. Reducing the accumulation of gas bubbles can help prevent non-uniformity in electrodeposition. Furthermore, anolyte volume may be reduced using the disclosed inert anode assemblies, at least due to the smaller volume of the anolyte flow channels of the inert anode assembly compared to the rest of the anode chamber.

[0291] Current bubble mitigation strategies often rely on the pitch and material "smoothness" of the ion-exchange membrane to move bubbles, combined with increased local fluid flow to direct bubbles away from the substrate surface. No matter how effective these variables are, bubbles can still accumulate under the membrane or under the substrate. Therefore, examples have also been disclosed for managing bubbles generated at the inert anode during the electrodeposition process. In one example, the anode chamber includes a bubble diverter. The bubble diverter acts as a physical barrier, directing the flow of bubbles generated at the inert anode to a stationary structure where the bubbles are vented to the atmosphere. Ions can pass under or through an opening in the bubble diverter. Therefore, the ionic current between the inert anode and the substrate is not blocked by the bubble diverter.

[0292] In some examples, one or more inert anodes are positioned around the inner periphery of the anode chamber, outside the target area for electrodeposition. The bubble diverter partially separates the ion exchange membrane and the substrate from the inert anode, preventing gas bubbles from affecting electrodeposition performance. The stationary structure can be installed within the anolyte circulation loop. The anolyte and gas bubbles can then flow through the stationary structure, removing the bubbles from the anolyte. A contactor can be employed to remove any remaining gas in the anolyte. The anolyte returning to the anode chamber is thus effectively degassed. Furthermore, in some examples, the bubble diverter includes multiple apertures that allow ionic current to pass through. The ionic current can be adjusted by changing the size of the apertures.

[0293] Before describing these examples in more detail, Figure 22 shows a schematic block diagram of another exemplary electroplating tool 2200. The electroplating tool 2200 is comprised of an electroplating cell 2202 having an anode chamber 2204 and a cathode chamber 2206. The electroplating tool 2200 further comprises an ion exchange membrane 2208 separating the anode chamber 2204 and the cathode chamber 2206, and a high resistance virtual anode (HRVA) 2209 within the cathode chamber 2206. The HRVA 2209 comprises an ionic resistance element that is in proximity to a suitably constant and uniform current source in proximity to the substrate cathode.

[0294] The anode chamber 2204 includes inert anodes 2210 and 2211. The anode chamber 2204 further includes an anolyte. The cathode chamber 2206 includes a catholyte. The catholyte includes ionic species that are deposited on the cathode layer of the substrate 2212 as a metal by electrochemical reduction. The anolyte includes a conductive electrolyte solution of a different composition than the catholyte. Bulk anolyte and / or catholyte solutions may be added from time to time to replenish the ionic species.

[0295] The ion exchange membrane 2208 prevents organic and anionic species from passing between the cathode chamber 2206 and the anode chamber 2204 while allowing cations to pass from the anode chamber 2204 to the cathode chamber 2206 .

[0296] The substrate holder 2213 is coupled to a substrate holder movement system 2214 that includes a lift 2215 configured to adjust the spacing between the substrate holder 2213 and the HRVA 2209. For example, the lift 2215 can lower the substrate holder 2213 to place the substrate 2212 in the catholyte for electroplating. The lift 2215 can also raise the substrate holder 2213 from the catholyte after electroplating. The substrate holder movement system 2214 can further include components that control the opening and closing of the substrate holder 2213.

[0297] Catholyte can be circulated between the cathode chamber 2206 and the catholyte reservoir 2220 by a combination of gravity in a catholyte circulation loop 2223 and one or more pumps 2222. Similarly, anolyte can be circulated through the anolyte reservoir 2224 and the anode chamber 2204 by a combination of gravity in an anolyte circulation loop 2227 and one or more pumps 2226.

[0298] Some electroplating tools use multiple plating cells to perform plating operations on multiple substrates in parallel. In some such examples, a central catholyte and / or anolyte reservoir can supply catholyte and / or anolyte to multiple plating cells. In other such examples, separate catholyte and / or anolyte reservoirs can be used to supply multiple plating cells. In still other examples, an electroplating tool can include a single plating cell. When an electroplating tool includes multiple plating cells, a single lift can be configured to lift two or more substrate holders for two or more different plating cells.

[0299] After the substrate 2212 is loaded into the substrate holder 2213, the substrate holder 2213 is lowered toward the HRVA 2209 by a lift 2215. In some examples, the substrate holder 2213 can be rotated by a rotation motor 2217 during electroplating. The substrate 2212 faces the surface of the HRVA 2209 and is separated from the HRVA 2209 by a plating gap during electroplating. An electric field is established between the anodes 2210 and 2211 and the substrate 2212. This electric field causes dissolved metal cations to migrate from the anode chamber 2204 into the cathode chamber 2206. At the substrate 2212, the metal cations are electrochemically reduced and deposited on the substrate 2212. An anode potential is applied to the anodes 2210 and 2212 via a charged plate 2228, and a cathode potential is provided to the cathode of the substrate 2212 via a cathode electrical connection 2229, completing a circuit. In some examples, anodes 2210 and 2211 are connected to the same anode potential. In other examples, anodes 2210 and 2211 are connected to different anode potentials.

[0300] As described, anodes 2210 and 2211 are inert anodes. Therefore, application of an anode potential to anodes 2210 and 2211 allows for the formation of protons and oxygen gas bubbles through the electrolysis of water. To prevent the oxygen gas bubbles from migrating to ion exchange membrane 2208 and disrupting the ionic current directed to substrate 2212, anodes 2210 and 2211 are positioned toward the periphery of anode chamber 2204. Additionally, bubble diverter 2230 is positioned laterally within anode chamber 2204 between anodes 2210 and 2211 and ion exchange membrane 2208. Bubble diverter 2230 is configured to direct the flow of bubbles generated at anodes 2210 and 2211 to stationary structure 2232, where the bubbles are vented to the atmosphere.

[0301] In this example, static structure 2232 is installed within anolyte circulation loop 2227. Air bubble diverter 2230 directs air bubbles generated at anode 2210 to static port 2233 and air bubbles generated at anode 2211 to static port 2234. Static ports 2233 and 2234 direct air bubbles into anolyte circulation loop 2227 upstream of static structure 2232. In this example, an additional static conduit 2235 is used to connect static port 2233 to anolyte circulation loop 2227.

[0302] Electroplating tool 2200 further comprises a computing system 2240, aspects of which are described in more detail below with respect to FIG. 30 . Computing system 2240 includes executable instructions for controlling the functionality of electroplating tool 2200. In some examples, computing system 2240 can be configured to communicate with a remote computing system 2245 over a suitable computer network. Remote computing system 2245 may include any suitable computing system. Examples include a networked workstation computer, an enterprise computing system, and / or a cloud computing system. Remote computing system 2245 can communicate with and control multiple electroplating tools in some examples.

[0303] 23 schematically illustrates an exemplary electrodeposition system 2300 with an inert anode, showing the formation of protons ([H+]) and oxygen bubbles (O). The electrodeposition system 2300 includes an anode chamber 2302 and a cathode chamber 2304. The electrodeposition system 2300 further includes an ion exchange membrane 2306 separating the anode chamber 2302 and the cathode chamber 2304. The ion exchange membrane 2306 is supported by a membrane frame 2308. The electrodeposition system 2300 further includes an HRVA 2310 disposed within the cathode chamber 2304.

[0304] 3, the anode chamber 2302 includes an anolyte reservoir 2312 in which are disposed inert anodes 2314 and 2315. The cathode chamber 2304 contains ionic copper (Cu) that is deposited on a substrate 2318, which serves as the cathode. 2+ ) containing a catholyte bath 2316. While primarily described with respect to copper deposition, other metal ion chemistries (e.g., including but not limited to, Au, Ag, Ni, Al, In, or Co) or metal alloy chemistries (e.g., including but not limited to, Ni / P, Ni / Co, Ni / Zn, Au / Cu, or Sn / Ag) can be used without departing from the scope of the present disclosure. The substrate 2318 is held in a substrate holder 2319 during deposition.

[0305] The anolyte reservoir 2312 is placed in an anolyte circulation loop 2320 that includes a pump 2324 and an anolyte reservoir (not shown). The catholyte reservoir 2316 is placed in a catholyte circulation loop 2322 that includes a pump 2326 and a catholyte reservoir 2328. A voltage source 2330 applies a voltage across the substrate 2318 and the inert anode 2314 to cause copper ions to flow for deposition onto the substrate 2318.

[0306] Catholyte enters the cathode chamber 2304 at inlet 2332 and exits at outlet 2334. The anolyte reservoir 2312 contains Cu 2+ In the scenario involving ions, the ion exchange membrane 2306 transfers Cu from the anolyte reservoir 2312 to the catholyte reservoir 2316. 2+ It is a cation exchange membrane that allows ions to pass through. Cu across the ion exchange membrane 2306 2+ Any ions replace at least some of the copper ions in the catholyte reservoir 2316 that are reduced on the substrate 2318. Cu 2+ Ions can also be replenished from catholyte reservoir 2328, regardless of the composition of anolyte reservoir 2312. As shown, ion exchange membrane 2306 is a cation exchange membrane, allowing protons to pass from anolyte reservoir 2312 to catholyte reservoir 2316. This ionic current causes Cu deposition on substrate 2318. 2+ Ions accumulate.

[0307] Anolyte enters the anode chamber 2302 at inlet 2336 and exits at outlet 2338. However, there may be more inlets and outlets, and the inlets and / or outlets may additionally or alternatively be located on the anode chamber base 2342 or in any suitable location.

[0308] As discussed above, for inert anodes 2314 and 2315, the oxidation and reduction reactions for copper electrodeposition include: 2H2O→O2+4H + +4e - (on an inert anode) Cu +2 +2e - → Cu (on the cathode) 2Cu 2+ +2H2O→2Cu+4H + +O2 (overall reaction)

[0309] Similar reactions may occur with other metal species. Therefore, unlike the active anodes, the inert anodes 2314 and 2315 do not generate metal cations in the anolyte reservoir 2312. Instead, circulating anolyte flows across the inert anodes 2314 and 2315, where water molecules are oxidized to form molecular oxygen and hydrogen ions. For every mole of copper plated at the cathode, 0.5 moles of molecular oxygen and 2 moles of protons (H + ) occurs at the inert anode. As discussed above, uniform plating on the substrate 2318 depends on mitigating the accumulation of gas bubbles in the ion exchange membrane 2306 without disrupting the ionic current between the inert anodes 2314 and 2315 and the substrate 2318.

[0310] Gas bubbles generated at the inert anode float upward. In traditional electrodeposition systems, the inert anode is placed below the substrate at or near the center of the anode chamber, causing the bubbles to float up to the membrane frame. With a membrane frame tilted upward toward the periphery of the anode chamber, the bubbles can drift toward the top corners of the membrane frame, where vents can be placed to remove the bubbles from the anolyte. However, if there is slack between the supports of the membrane frame, the bubbles can become trapped in the slack.

[0311] Therefore, electrodeposition system 2300 is designed to deflect the flow of gas bubbles so that they do not impinge on membrane frame 2308 or ion exchange membrane 2306. In this example, inert anodes 2314 and 2315 are located toward the periphery of anode chamber 2302 (e.g., closer to anode chamber outer wall 2340 than to the center of anode chamber 2302). In this way, gas bubbles floating directly above inert anodes 2314 and 2315 are less likely to impinge on ion exchange membrane 2306 than would be the case with inert anodes centrally located below substrate 2318.

[0312] A bubble diverter 2345 is mounted in the anode chamber 2302 to reduce the passage of air bubbles toward the ion exchange membrane 2306. As shown in FIG. 23 , the bubble diverter 2345 is positioned so that air bubbles that float directly up from the inert anodes 2314 and 2315 pass along the outer wall 2348 of the bubble diverter 2345, opposite the ion exchange membrane 2306. The bubble diverter 2345 is positioned between the membrane frame 2308 and the anode chamber base 2342. A membrane interface seal 2346 (e.g., an O-ring) is positioned between the membrane frame 2308 and the bubble diverter 2345. The membrane interface seal 2346 prevents air bubbles from crossing the outer wall 2348 at the interface between the bubble diverter 2345 and the membrane frame 2308. The membrane frame 2308 is secured to the bubble diverter 2345 and can exert downward pressure on the bubble diverter 2345, increasing the strength of the seal between the two parts. The base of the bubble diverter 2345 can be attached to, rest on, or inserted into the anode chamber base 2342.

[0313] In this example, the inert anodes 2314 and 2315 are located outside the bubble diverter 2345, and the ion exchange membrane 2306 is located inside the bubble diverter 2345. An outer wall 2348 of the bubble diverter 2345 partially separates the area of the anode chamber 2302 adjacent the ion exchange membrane 2306 from the area of the anode chamber 2302 configured to direct the flow of bubbles into the anode circulation loop 2320. The bubble diverter 2345 can direct the flow of bubbles generated at the inert anodes 2314 and 2315 to a stationary structure 2350, where the bubbles are vented to the atmosphere. The stationary structure 2350 can be any suitable structure capable of releasing undissolved gases to evaporate into the atmosphere. The stationary structure can be shaped as a pillar or have any other suitable configuration.

[0314] In the depicted example, the bottom edge 2352 of the bubble diverter 2345 is spaced from the anode chamber base 2342, forming a gap 2354 that allows ionic current to flow between the inert anodes 2314 and 2315 and the ion exchange membrane 2306. The gap 2354 also allows anolyte to flow beneath the bottom edge 2352 of the bubble diverter 2345. Protons generated at the inert anodes 2314 and 2315 flow toward and across the ion exchange membrane 2306 into the catholyte reservoir 2316. The ionic current generated by the protons aids in the deposition of copper ions from the catholyte onto the substrate 2318.

[0315] In other embodiments, as described in more detail below, the bottom edge 2352 of the bubble diverter 2345 can include apertures that allow ionic current and anolyte flow to pass through. In some examples, such apertures can be covered with a membrane or mesh grid to further restrict the passage of bubbles to the ion exchange membrane 2306. Additionally, as further described with respect to FIGS. 26A-26B and 27A-27B, in some examples, the apertures have a variable open cross-sectional area. The size of the aperture opening, the thickness of the outer wall 2348, and the distance from the outer wall 2348 to the inert anodes 2314 and 2315 can be varied to control the ionic current.

[0316] Bubble diverter 2345 is shaped to direct bubbles away from ion exchange membrane 2306 and towards stationary structure 2350. In this example, bubble diverter 2345 includes a conical region 2356 that directs bubbles generated at inert anodes 2314 and 2315 towards stationary ports 2364 and 2365, respectively. In some examples, bubble diverter 2345 includes grooves or channels on its outer surface to direct the bubbles.

[0317] Static ports 2364 and 2365 are configured to direct gas bubbles from anode chamber 2302 to stationary structure 2350. In this example, stationary port 2364 connects to channel 2366, and stationary port 2365 connects to channel 2367. Channel 2366 and channel 2367 are fluidly coupled to stationary structure 2350. Anolyte circulation loop 2320 also passes through stationary structure 2350 via conduit 2368. In some examples (e.g., as described with respect to FIG. 24 ), channels 2366 and 2367 merge with anolyte circulation loop 2320 upstream of stationary structure 2350. Static ports 2364 and 2365 can be positioned based in part on the fluid flow pattern from anolyte circulation loop 2320 to further bias gas bubble passage from anode chamber 2302. For example, static ports 2364 and 2365 can be located in areas of localized high flow velocity (eg, at or near inlet 2336 and / or outlet 2338).

[0318] In some examples, one or more sensors can be positioned in and around electrodeposition system 2300 to monitor conditions and provide indications of plating non-uniformities, which may indicate gas bubble buildup and / or non-uniform ion current through ion exchange membrane 2306. For example, electrodeposition system 2300 can include a cathode current sensor array 2372 and / or an optical sensor 2376. Cathode current sensor array 2372 can monitor current at discrete points on substrate 2318. Optical sensor 2376 can be positioned to observe the surface of ion exchange membrane 2306 to visually monitor for gas bubble buildup. Optical sensor 2376 can comprise a photodiode, a camera, and / or any other suitable optical sensing device. Additional optical and / or other sensors beyond those shown can be positioned in and around electrodeposition system 2302.

[0319] 24 schematically illustrates an exemplary anolyte circulation loop 2400. The anolyte circulation loop 2400 is an example of the anolyte circulation loops 2227 and / or 2320. The anolyte circulation loop 2400 includes an anode chamber 2402, an anolyte reservoir 2404, and a circulation pump 2406. Although the anolyte reservoir 2404 is illustrated as being upstream of the circulation pump 2406, the anolyte reservoir 2404 could alternatively be located downstream of the circulation pump 2406.

[0320] In addition to affecting the flow of ionic current during electrodeposition, gas bubbles can also obstruct flow through the anolyte circulation loop if gas accumulates in the recirculation line. Within the anode chamber 2402, a bubble diverter 2408 directs the flow of gas bubbles into the anolyte circulation loop 2400. A stationary structure 2410 is positioned upstream of the circulation pump 2406. The stationary structure 2410 is exposed to the atmosphere. The stationary structure 2410 can be formed from any material that is compatible with the chemicals to which the anode chamber 2402 is exposed. In some examples, the stationary structure 2410 is made from tetrafluoroethylene tubing.

[0321] The anode chamber 2402 includes an anolyte inlet 2412 and an anolyte outlet 2414. The anode chamber 2402 further includes quiescent ports 2416 and 2418. A bubble diverter 2408 directs the flow of gas bubbles into the quiescent ports 2416 and 2418, although some gas bubbles may exit the anode chamber 2402 through the anolyte outlet 2414.

[0322] Static port 2416 leads to channel 2420 which connects to anolyte circulation loop 2400. Similarly, static port 2418 leads to channel 2422 which also connects to anolyte circulation loop 2400. As shown, the outlet ports and channels exiting anode chamber 2402 all merge into a common flow line 2424 which leads to static structure 2410.

[0323] The stationary structure 2410 can be tall enough to prevent overflow and wide enough to vent most of the incoming gas bubbles to the atmosphere. The height of the fluid column in the stationary structure 2410 is typically at least higher than the level of fluid in the anode chamber 2402, and in some instances higher than the overall level of fluid in the electrodeposition chamber.

[0324] While stationary structure 2410 can remove most of the air bubbles, dissolved gases may remain in the anolyte exiting stationary structure 2410. Therefore, anolyte circulation loop 2400 further comprises a contactor 2426 downstream of stationary structure 2410 and upstream of circulation pump 2406. Contactor 2426 is configured to remove dissolved gases from the circulating anolyte. For example, contactor 2426 can comprise a filter or membrane to which a vacuum 2428 is applied that separates the fluid from the gas. Contactor 2426 can further comprise an exhaust port connected to a vacuum source to allow gases to be vented to the atmosphere.

[0325] Once the anolyte has passed through stationary structure 2410 and contactor 2426, it returns to anode chamber 2402 in a substantially degassed state. In some examples, contactor 2426 can remove both dissolved and undissolved gas. For example, contactor 2426 can be used alone, without a stationary post, during electrodeposition processes involving very low currents of relatively long duration that do not generate excessive gas bubbles.

[0326] FIG. 25 shows a schematic overhead view of the relative positions of some components of an exemplary electrodeposition system 2500. The electrodeposition system 2500 is an example of the electrodeposition system 2300. Depicted within the electrodeposition system 2500 are the locations of an outer chamber wall 2505, an outer bubble diverter wall 2510, and a membrane frame perimeter 2515. A substrate perimeter 2520 is also shown. The outer bubble diverter wall 2510, the membrane frame perimeter 2515, and the substrate perimeter 2520 are shown as having slightly different diameters, but in a physical example, they may be closer and coincident. The outer bubble diverter wall 2510 extends around the membrane frame perimeter 2515. The outer bubble diverter wall 2510 is continuous with the lower bubble diverter wall 2525, and they are connected by a conical region (e.g., conical region 2356 as shown in FIG. 23).

[0327] The substrate periphery 2520 defines a substrate window 2530, shown in FIG. 25 as the shaded region. The substrate window 2530 is a volume (cylindrical in this example) extending from the substrate to the base of the anode chamber of the electrodeposition system 2500. The substrate window 2530 represents a target for ionic current across the ion exchange membrane and may represent a target to be maintained free of bubbles. Inert anodes 2535 and 2537 are depicted as peripheral anodes, positioned between the outer chamber wall 2505 and the lower bubble diverter wall 2525 and extending around the periphery of the substrate window 2530. The strength of the ionic current generated is a function of the distance 2545 between the inert anodes 2535 and 2535 and the lower bubble diverter wall 2525. Gas bubbles are therefore generated outside the substrate window 2530 at the inert anodes 2535 and 2537 and directed to the static ports 2540 and 2542, which are also located outside the substrate window 430.

[0328] Ion current through the bubble diverter, in the form of protons generated at the inert anode, is based in part on the open cross-sectional area of the aperture. By adjusting the overall cross-sectional area, the density and / or flow of ion current can be adjusted accordingly. The bubble diverter aperture can be customized for a particular electrodeposition process, for example, by machining the aperture to a desired height.

[0329] In some examples, the bubble diverter can include an adjustment mechanism configured to adjust the open cross-sectional area of the multiple apertures. Such adjustments can occur during setup, in situ, between electrodeposition processes, or during the process. Adjustments can increase ion current flow by increasing the aperture size or decrease ion current flow by decreasing the aperture size. For example, substrates that have undergone an electrodeposition process can be evaluated by metrology. If the metrology indicates that a change in ion current is necessary, the apertures can be adjusted prior to electrodepositing the next substrate. For example, some wafers may have a high seed resistance and require more terminal effect than wafers with a low seed resistance. Such adjustments allow users to fine-tune the performance of the anode, providing greater flexibility compared to electrodeposition systems that only allow adjustment of the cathode.

[0330] As an example, the adjustment mechanism for varying the aperture cross-sectional area of the bubble diverter can comprise a shutter system. An exemplary shutter system is shown in FIGS. 26A-26B. At 2600, FIG. 26A shows a portion of an anode chamber 2602 in a first configuration with a bubble diverter 2603 having an actuatable shutter system 2604. The anode chamber 2602 is configured with an inert anode 2605 positioned in contact with the anolyte 2606. Application of a voltage V1 to the inert anode 2605 oxidizes water, forming oxygen gas bubbles, as shown at 2608, and protons, as shown at 2610. The bubble diverter directs the gas bubbles to a quiescent port 2611.

[0331] The bubble diverter 2603 includes apertures 2612 and 2614, each having a rectangular cross-sectional area with a height (h) and a width (w1). A first shutter 2616 is associated with aperture 2612, and a second shutter 2618 is associated with aperture 2614. In this example, the first shutter 2616 and the second shutter 2618 adjust the cross-sectional area of apertures 2612 and 2614 by changing the opening width of the respective apertures. In other examples, the shutters can adjust the opening height. In some examples, each shutter is individually adjustable. In other examples, the shutters are adjusted as a group. For example, the first shutter 2616 and the second shutter 2618 can be part of a threaded, rotatable ring with alternating apertures and solid portions located either inside or outside the bubble diverter 2603. Thus, movement of the rotatable ring aligns or misaligns the aperture of the ring with the aperture of the bubble diverter 2603, for example, in an aperture configuration. The first shutter 2616 and the second shutter 2618 can be adjusted manually or automatically. For example, a controller 2620 can be employed to send signals to activate mechanisms that adjust the positions of the first shutter 2616 and the second shutter 2618.

[0332] As shown at 2600, apertures 2612 and 2614 are fully open to a width w1, resulting in the maximum operable ion current, as shown at 2625. In FIG. 26B, first shutter 2616 and second shutter 2618 are actuated via controller 2620 at 2650 to narrow the opening width of apertures 2612 and 2614 from w1 to w2. Thus, the ion current is reduced from the maximum operable ion current, as shown at 2655. Note that this change in ion current does not require adjustment of applied voltage V1.

[0333] Another system for regulating ion current through a bubble diverter is shown in FIGS. 27A-27B. At 2700, FIG. 27A shows a portion of an anode chamber 2702 in a first configuration with a bubble diverter 2703 that is movable relative to a base 2704 of the anode chamber 2702. The anode chamber 2702 includes an inert anode 2705 disposed in contact with an anolyte 2706. Application of a voltage V1 to the inert anode 2705 oxidizes water, forming oxygen gas bubbles, as shown at 2708, and protons, as shown at 2710. The bubble diverter directs the gas bubbles to a stationary port 2711. The bubble diverter 2703 includes apertures 2712 and 2714 located along the bottom edge of the bubble diverter 2703, each having a rectangular cross-sectional area with a height (h) and a width (w1). A controller can be employed to actuate adjustment mechanism 2719. Adjustment mechanism 2719 can be, for example, a motor or pneumatic device and can be operable as a mechanism to adjust the position of the bubble diverter relative to the base of the anode chamber. As shown in 2700, the bottom edge 2720 of bubble diverter 2703 abuts base 2704, providing a minimum operable ion current, as shown in 2722.

[0334] 27B , adjustment mechanism 2719 is actuated by controller 2718 to raise bubble diverter 2703, as shown at 2750. In this configuration, bottom edge 2720 of bubble diverter 2703 no longer contacts base 2704. Rather, a gap 2752 of height h2 is created around the periphery of bubble diverter 2703. Thus, ionic current through bubble diverter 2703 increases, as shown at 2755. In some examples, a portion of bubble diverter 2703 is inserted into base 2704, allowing the height h1 of apertures 2712 and 2714 to be adjusted. For example, a dynamic seal can be provided around a hole in base 2704 so that a portion of the bubble diverter can rise into and fall out of base 2704.

[0335] FIG. 28 is a flow diagram illustrating an exemplary method 2800 of operating an electrodeposition system, such as an electroplating tool 2200, an electrodeposition system 2300, and an electrodeposition system including an anode chamber 2602 or 2702. At 2810, method 2800 includes generating gas bubbles at an inert anode disposed in an anode chamber of the electrodeposition system by applying a voltage across the inert anode and the substrate. At 2820, method 2800 includes directing the gas bubbles generated at the inert anode to a stationary structure using a gas bubble diverter, the stationary structure being exposed to the atmosphere. In some examples, directing the gas bubbles to the stationary structure includes diverting the flow of the gas bubbles to at least one channel leading to the anolyte circulation loop. In some examples, method 2800 further includes flowing anolyte through the anolyte circulation loop such that the gas bubbles enter the stationary structure upstream of the circulation pump. In some examples, the method 2800 further includes flowing the anolyte through a contactor located downstream of the stationary structure, the contactor configured to remove dissolved gases from the anolyte.

[0336] FIG. 29 is a flow diagram illustrating an exemplary method 2900 for adjusting ion current in an electrodeposition system with an inert anode, such as an electrodeposition system with an anode chamber 2602 or 2702. At 2910, method 2900 includes generating ion current at the inert anode. At 2920, method 2900 includes flowing the ion current through an aperture of a bubble diverter. At 2930, method 2900 includes adjusting the ion current at the substrate by adjusting the open cross-sectional area of at least one aperture of the bubble diverter in response to a plating performance indicator. In some examples, the open cross-sectional area of the aperture is adjusted via a shutter system. In some examples, the open cross-sectional area of the aperture can be adjusted by adjusting the position of the bubble diverter relative to the base of the anode chamber. In one example, adjusting the ion current includes maintaining a voltage applied between the inert anode and the substrate. In some examples, the adjustment of the ion current can be performed during an electrodeposition operation. Additionally, in some instances, adjustments to the ion current can be made prior to the electrodeposition operation. In some instances, the indicator of plating performance includes a detected current at the substrate.

[0337] Such a method helps remove gas bubbles generated at the inert anode while they are in suspension, so that they cannot precipitate on the ion exchange membrane and interfere with electrodeposition.

[0338] In some embodiments, the methods and processes described herein may be coupled to a computing system of one or more computing devices. In particular, such methods and processes may be implemented as a computer application program or service, an application programming interface (API), a library, and / or other computer program product.

[0339] 30 schematically illustrates a non-limiting example of a computing system 3000 that may implement one or more of the methods and processes described above. The computing system 3000 is illustrated in simplified form. The computing system 3000 may take the form of one or more personal computers, workstations, computers integrated with substrate processing tools, and / or network-accessible server computers.

[0340] Computing system 3000 includes a logic subsystem 3002 and a storage subsystem 3004. Computing system 3000 may optionally include a display subsystem 3006, an input subsystem 3008, a communication subsystem 3010, and / or other components not shown in Figure 30. Computing systems 150, 152, 1340, 2240, and 2245, and controllers 1608, 2014, 2620, and 2178 are examples of computing systems 3000.

[0341] The logical subsystem 3002 includes one or more physical devices configured to execute instructions. For example, the logical subsystem may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical entities. Implementing such instructions may perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.

[0342] A logical subsystem may include one or more processors configured to execute software instructions. Additionally or alternatively, a logical subsystem may include one or more hardware or firmware logical subsystems configured to execute hardware or firmware instructions. The processors of a logical subsystem may be single-core or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and / or distributed processing. Individual components of a logical subsystem may optionally be distributed among two or more separate devices, which may be remotely located and / or configured for cooperative processing. Aspects of a logical subsystem may be virtualized and executed by remotely accessible networked computing devices configured in a cloud computing configuration.

[0343] The storage subsystem 3004 includes one or more physical devices configured to hold instructions 3012 executable by the logical subsystem to implement the methods and processes described herein. When such methods and processes are implemented, the state of the storage subsystem 3004 may be transformed, for example, to hold different data.

[0344] The storage subsystem 3004 may include removable and / or internal devices. The storage subsystem 3004 may include optical memory (e.g., CD, DVD, HD-DVD, Blu-ray disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and / or magnetic memory (e.g., hard disk drive, floppy disk drive, tape drive, MRAM, etc.), among others. The storage subsystem 3004 may include volatile, non-volatile, dynamic, static, read / write, read-only, random access, sequential access, location-addressable, file-addressable, and / or content-addressable devices.

[0345] It will be understood that storage subsystem 3004 includes one or more physical devices, however, aspects of the instructions described herein may alternatively be propagated by a communications medium (e.g., electromagnetic signals, optical signals, etc.) that is not carried for a finite duration by a physical device.

[0346] Aspects of logic subsystem 3002 and storage subsystem 3004 may be integrated into one or more hardware logic components, which may include, for example, field programmable gate arrays (FPGAs), program and application specific integrated circuits (PASICs / ASICs), program and application specific standard products (PSSPs / ASSPs), systems on a chip (SOCs), complex programmable logic devices (CPLDs), etc.

[0347] If included, the display subsystem 3006 may be used to present a visual representation of the data maintained by the storage subsystem 3004. This visual representation may take the form of a graphical user interface (GUI). As the methods and processes described herein modify the data maintained by the storage subsystem, thereby transforming the state of the storage subsystem, the state of the display subsystem 3006 may likewise be transformed to visually represent the changes in the underlying data. The display subsystem 3006 may include one or more display devices utilizing virtually any type of technology. Such display devices may be combined with the logic subsystem 3002 and / or the storage subsystem 3004 in a shared enclosure, or such display devices may be peripheral display devices.

[0348] If included, the input subsystem 3008 may comprise or interface with one or more user input devices (such as a keyboard, mouse, or touchscreen). In some examples, the input subsystem may comprise or interface with selected natural user input (NUI) components. Such components may be integrated or peripheral, and translation and / or processing of input actions may be handled on-board or off-board. Exemplary NUI components may include microphones for speech and / or voice recognition, and infrared, color, stereo, and / or depth cameras for machine vision and / or gesture recognition.

[0349] If included, the communications subsystem 3010 may be configured to communicatively couple the computing system 3000 to one or more other computing devices. The communications subsystem 3010 may include wired and / or wireless communications devices compatible with one or more different communications protocols. As a non-limiting example, the communications subsystem may be configured for communications over a wireless telephone network, or a wired or wireless local or wide area network. In some examples, the communications subsystem may enable the computing system 3000 to send and / or receive messages to and / or from other devices over a network, such as the Internet.

[0350] It will be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific examples are not to be considered in a limiting sense, as numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, the various acts shown and / or described may be performed in the sequence shown and / or described, in other sequences, in parallel, or omitted. Similarly, the order of the processes described above may be varied.

[0351] The subject matter of the present disclosure includes novel and non-obvious combinations and sub-combinations of the various processes, systems and configurations, other features, functions, acts, and / or attributes disclosed herein, and all equivalents thereof.

Claims

1. 1. An electrodeposition system comprising: a substrate holder; a cathode chamber configured to hold a catholyte; an anode chamber with an inert anode, the anode chamber configured to hold an anolyte; an intermediate chamber disposed between the cathode chamber and the anode chamber, the intermediate chamber being separated from the cathode chamber by an ion exchange membrane; An electrodeposition system comprising:

2. 10. The electrodeposition system of claim 1, The electrodeposition system, wherein the intermediate chamber is separated from the anode chamber by a proton inhibiting structure.

3. 3. The electrodeposition system of claim 2, The proton-blocking structure has a metal redox barrier, The metal redox barrier is configured to undergo growth of a metal film on the anode side of the metallic redox barrier by reduction of metal ions from an anolyte in contact with the anode side of the metallic redox barrier; An electrodeposition system configured to provide metal ions to a solution in contact with a cathode side of the metal redox barrier by oxidation of the metal redox barrier.

4. 4. The electrodeposition system of claim 3, The electrodeposition system further comprising a mechanical biasing element for biasing the metallic redox barrier toward the intermediate chamber.

5. 4. The electrodeposition system of claim 3, An electrodeposition system, wherein the metal redox barrier is configured to be rotatable so that the anode side and the cathode side alternately face toward the intermediate chamber.

6. 3. The electrodeposition system of claim 2, The electrodeposition system, wherein the proton-inhibiting structure comprises an anion-exchange membrane.

7. 7. The electrodeposition system of claim 6, The electrodeposition system wherein the ion exchange membrane separating the intermediate chamber and the cathode chamber comprises a second anion exchange membrane.

8. 7. The electrodeposition system of claim 6, The electrodeposition system, wherein the ion exchange membrane separating the intermediate chamber and the cathode chamber comprises a cation exchange membrane.

9. 7. The electrodeposition system of claim 6, The electrodeposition system further comprising a redox shuttle circulation system configured to provide a redox shuttle species to the anode chamber.

10. 10. The electrodeposition system of claim 9, The electrodeposition system, wherein the redox shuttle circulation system comprises a redox shuttle species regeneration chamber.

11. 10. The electrodeposition system of claim 1, the ion exchange membrane is a first cation exchange membrane; The electrodeposition system wherein the intermediate chamber is separated from the anode chamber by a second cation exchange membrane.

12. 12. The electrodeposition system of claim 11, The electrodeposition system further comprising a copper oxide module fluidly coupled to the intermediate chamber.

13. 1. An electrodeposition system comprising: a cathode chamber configured to hold a catholyte; a substrate holder configured to expose a substrate to said catholyte during an electrodeposition process; 1. An inert anode assembly comprising: one or more inert anodes; two or more anolyte flow channels defining segmented regions of anolyte flow across the one or more inert anodes; an inert anode assembly having an ion exchange membrane disposed between the cathode chamber and the two or more anolyte flow channels; An electrodeposition system comprising:

14. 14. The electrodeposition system of claim 13, the inert anode assembly further comprising a cathode chamber bottom piece, the cathode chamber bottom piece comprising an opening positioned opposite one of the two or more anolyte flow channels.

15. 15. The electrodeposition system of claim 14, the two or more anolyte flow channels are formed in an anolyte channel component; The electrodeposition system, wherein the ion exchange membrane is disposed between the cathode chamber bottom component and the anolyte channel component.

16. 16. The electrodeposition system of claim 15, the inert anode assembly further comprising an intermediate channel component disposed between the cathode chamber bottom component and the anolyte channel component; the ion exchange membrane is a first ion exchange membrane disposed between the intermediate channel component and the anolyte channel component; The electrodeposition system further comprising a second ion exchange membrane disposed between the cathode chamber bottom component and the middle channel component.

17. 1. An electrodeposition system comprising: a cathode chamber configured to hold a catholyte; an anode chamber configured to hold an anolyte; a membrane frame supporting an ion exchange membrane disposed between the cathode chamber and the anode chamber; a substrate holder configured to expose a substrate to said catholyte during an electrodeposition process; an inert anode disposed within the anode chamber; a bubble diverter positioned to direct a flow of bubbles generated at the inert anode to a stationary structure where the bubbles are vented to the atmosphere; An electrodeposition system comprising:

18. 18. The electrodeposition system of claim 17, The electrodeposition system, wherein the bubble diverter extends around a peripheral portion of the ion exchange membrane.

19. 18. The electrodeposition system of claim 17, further comprising an anolyte circulation loop having a circulation pump; the bubble diverter directs the flow of bubbles into the anolyte circulation loop; the stationary structure is disposed upstream of the circulation pump; An electrodeposition system wherein the stationary structure is exposed to the atmosphere.

20. 20. The electrodeposition system of claim 19, the anolyte circulation loop further comprises a contactor downstream of the stationary structure and upstream of the circulation pump; The electrodeposition system, wherein the contactor is configured to remove dissolved gases from the anolyte.

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