Electroplating bath neutralization

Abstract

A plating system or apparatus is configured to neutralize other hardware components in a plating bath and / or a plating bath circuit for maintenance with minimal exposure to acidic and hazardous chemicals. A neutralizing solution, such as deionized water, is delivered to the plating bath circuit. The selected plating bath is isolated for neutralization such that the neutralized solution bypasses the electrolyte storage tank. The selected plating bath is suctioned to remove residual chemicals and then filled with a neutralizing solution. The suction and filling processes are repeated until the pH of the solution of the selected plating bath reaches a safety critical value.

Description

[0001] Incorporation by Reference The PCT Application Table, which is part of this application, is filed concurrently with the specification. Each of the applications listed in the concurrently filed PCT Application Table from which this application claims benefit or priority is incorporated by reference herein in its entirety and for all purposes. TECHNICAL FIELD

[0002] The present disclosure relates to methods, apparatuses, and tools for electroplating materials on substrates. In particular, the present disclosure relates to neutralization processes performed on electroplating tanks, filters, and other components of electroplating apparatuses or tools. BACKGROUND

[0003] Electrochemical deposition is currently used to meet commercial demands for complex packaging and multi-chip interconnect technologies, which are generally known and commonly referred to as wafer level packaging (WLP) and through-silicon via (TSV) electrical connection technologies. These technologies present significant challenges in their own right, in part because the feature sizes are generally large (compared to front end of line (FEOL) interconnects) and the aspect ratios are high.

[0004] Electroplating tools and apparatuses utilize electroplating reflow loops to deliver electrolyte for electrochemical deposition of metals. Such electroplating reflow loops can be composed of many components, such as tanks, pumps, filters, flow meters, degassers, isolation valves, and electroplating tanks. Electroplating tanks can include stacked components that form a separate anode chamber that houses an anode, an electroplating chamber, a cross-flow region, and a drain region. Typically, one or more components of the electroplating tool or apparatus need to be serviced by a service engineer or technician, which exposes the service engineer or technician to hazardous chemicals.

[0005] The background description provided herein is for the purpose of generally presenting the context of the disclosure. The work of the presently designated inventors, to the extent the work is described in this background section, as well as aspects of the description that can not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. SUMMARY

[0006] An electroplating apparatus is provided herein. The electroplating apparatus includes a reservoir configured to hold an electroplating solution, a pump, and one or more electroplating cells. Each of the one or more electroplating cells includes a cathode chamber, an anode chamber configured to hold an anode, and a septum between the cathode chamber and the anode chamber. The electroplating apparatus further includes a feed line fluidly coupled with an outlet of the pump and the one or more electroplating cells, and a return line fluidly coupled with the one or more electroplating cells and further fluidly coupled with one or more of (1) a reservoir return line, wherein the reservoir return line is fluidly coupled with the reservoir, (2) a bypass return line, wherein the bypass return line bypasses the reservoir and is fluidly coupled with the pump, and (3) a drain line, wherein the drain line leads to a waste section. The electroplating apparatus further includes a neutralization fill line fluidly coupled with the one or more electroplating cells and configured to provide a neutralization solution to the one or more electroplating cells.

[0007] In some implementations, the neutralization solution includes deionized water. In some implementations, the inlet of the pump is fluidly coupled with the bypass return line and a tank output line. In some implementations, the return line is fluidly coupled with the drain line, wherein the neutralization fill line is configured to circulate the neutralization solution through the one or more electroplating cells and to the drain line via the return line. In some implementations, the return line is fluidly coupled with the bypass return line, wherein the neutralization fill line is configured to circulate the neutralization solution through the one or more electroplating cells and the bypass return line via the pump and the feed line. In some implementations, the return line is fluidly coupled with the tank, wherein the neutralization fill line circulates the neutralization solution to the bypass return line or the drain line, bypassing the tank. In some implementations, the electroplating device further includes a drain line, wherein the drain line is fluidly coupled with the return line or the feed line. In some implementations, the electroplating device further includes a suction line fluidly coupled with the one or more electroplating cells, wherein the suction line includes a main body suction valve configured to suction the one or more electroplating cells. In some implementations, each of the one or more electroplating cells further includes an ion resistive element positioned above the diaphragm. In some implementations, each of the one or more electroplating cells further includes a diaphragm frame configured to support the diaphragm. In some implementations, the electroplating device further includes an HRVA chamber suction line fluidly coupled with an area below the ion resistive element in the one or more electroplating cells, wherein the HRVA chamber suction line includes an HRVA chamber suction valve configured to suction the area below the ion resistive element. In some implementations, the electroplating device further includes a system controller configured with instructions to: (a) open a drain isolation valve between the return line and the tank to return electrolyte in the one or more electroplating cells to the tank; (b) close the drain isolation valve to isolate a selected one or more electroplating cells from the tank; (c) open one or both of the main body suction valve and the HRVA chamber suction valve to suction the selected one or more electroplating cells; and (d) open a neutralization fill valve connected with the neutralization fill line to fill the selected one or more electroplating cells with the neutralization solution. In some implementations, the system controller is further configured with instructions to repeat steps (c) and (d) until a pH of a solution from the selected one or more electroplating cells reaches a safe threshold value.In some implementations, the system controller is further configured with instructions to: after step (c) is completed and before step (d), close the main body draw valve and the HRVA chamber draw valve after drawing the selected one or more electroplating cells; and after step (d) is completed, close the neutralization fill valve. In some implementations, the system controller is further configured with instructions to: after step (d), open a recirculation valve connected with the return line and the bypass return line to recirculate the neutralization solution through the selected one or more electroplating cells. In some implementations, the electroplating apparatus further comprises: a second neutralization fill line fluidically coupled with the one or more electroplating cells, wherein the second neutralization fill line comprises a second neutralization fill valve configured to provide a second neutralization solution to a tower fluidically coupled with the one or more electroplating cells; and an anode chamber draw line fluidically coupled with the tower, wherein the anode chamber draw line comprises an anode chamber draw valve configured to draw the tower, wherein the system controller is further configured with instructions to: after step (d), open the second neutralization fill valve to fill the tower with the second neutralization solution; and after filling the tower with the second neutralization solution, close the second neutralization fill valve. In some implementations, the neutralization fill line further comprises a precursor dosing valve to dose a precursor to the one or more electroplating cells, wherein the system controller is further configured with instructions to: before step (d), open the precursor dosing valve to dose the precursor to the selected one or more electroplating cells. In some implementations, the precursor comprises methylsulfonic acid (MSA) and prevents precipitation when the neutralization solution is mixed with the electroplating solution. In some implementations, the electroplating apparatus further comprises: a system controller configured with instructions to: (a) select at least one of the one or more electroplating cells for isolation and neutralization with the neutralization solution; (b) draw the at least one of the selected one or more electroplating cells; (c) neutralize the at least one of the selected one or more electroplating cells with the neutralization solution; and (d) electroplate metal on one or more wafers in the one or more electroplating cells that are not selected for isolation and neutralization, wherein electroplating metal on the one or more wafers is performed concurrently with performing steps (b)-(c). In some implementations, the feed line comprises a filter downstream of the pump, wherein the neutralization fill line is configured to provide the neutralization solution to the pump and flow the neutralization solution through the feed line and the filter.In some implementations, the electroplating apparatus further comprises a system controller configured with instructions to: (a) close a tank isolation valve connected with the feed line to isolate the pump from the one or more electroplating tanks; and (b) open a neutralizing fill valve connected with the neutralizing fill line to flush the filter with the neutralizing solution.

[0008] Also provided herein is a method for neutralizing one or more electroplating tanks in an electroplating apparatus. The method comprises: isolating a selected one or more electroplating tanks from a reservoir in the electroplating apparatus configured to hold an electroplating solution; pumping the selected one or more electroplating tanks; filling the selected one or more electroplating tanks with a neutralizing solution; and repeating the operations of pumping and filling with the neutralizing solution until a pH of a solution from the one or more electroplating tanks reaches a safe threshold value.

[0009] In some implementations, the neutralizing solution comprises deionized water. In some implementations, the neutralizing solution comprises a base. In some implementations, pumping the selected one or more electroplating tanks comprises: opening a first pump valve fluidly coupled with the selected one or more electroplating tanks, wherein each of the electroplating tanks comprises a cathode chamber, an anode chamber, and an ionically resistive element between the cathode chamber and the anode chamber; and opening a second pump valve fluidly coupled with an area below the ionically resistive element in the selected one or more electroplating tanks. In some implementations, the method further comprises: after filling the selected one or more electroplating tanks with the neutralizing solution, recirculating the neutralizing solution through the selected one or more electroplating tanks. In some implementations, the method further comprises: prior to isolating the selected one or more electroplating tanks, recovering electrolyte from the one or more electroplating tanks into the reservoir. In some implementations, the method further comprises: electroplating metal onto one or more wafers in the one or more electroplating tanks that are not selected for isolation and neutralization, wherein electroplating metal onto the one or more wafers occurs concurrently with pumping and filling the selected one or more electroplating tanks with the neutralizing solution.

[0010] Also provided herein is a method of performing a filter flush. The method comprises: isolating a pump from one or more electroplating tanks in an electroplating apparatus, wherein the pump is configured to draw an electroplating solution from a reservoir; pumping a filter downstream of the pump, wherein the filter is fluidly coupled with the one or more electroplating tanks; flushing the filter with a neutralizing solution using a neutralizing fill valve fluidly coupled with a feed line; and repeating the operations of pumping and flushing with the neutralizing solution until a pH of a solution from the filter reaches a safe threshold value.

[0011] In some implementations, the neutralization solution includes deionized water. In some implementations, the neutralization solution includes a base. BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 shows a schematic diagram of a flow circuit of an electroplating apparatus having multiple electroplating cells in fluid communication with an electrolyte reservoir.

[0013] FIG. 2 shows a schematic diagram of an exemplary flow circuit of an electroplating apparatus having a neutralization flush line that bypasses the electrolyte reservoir, according to some implementations.

[0014] FIG. 3A shows a schematic diagram of an exemplary flow circuit of an electroplating apparatus having a drain line that bypasses the electrolyte reservoir, according to some implementations.

[0015] FIG. 3B shows a schematic diagram of an alternative flow circuit of an electroplating apparatus having a drain line that bypasses the electrolyte reservoir, according to some implementations.

[0016] FIG. 3C shows a schematic diagram of an alternative flow circuit of an electroplating apparatus, according to some implementations.

[0017] FIG. 4A shows a schematic diagram of an exemplary electroplating cell that utilizes a combination of lateral flow and impinging flow on a substrate surface during electroplating.

[0018] FIG. 4B shows a cross-sectional view of multiple hardware components in an electroplating cell.

[0019] FIG. 4C shows an isometric cross-sectional view of an electroplating cell that includes a high resistance virtual anode (HRVA) chamber.

[0020] FIG. 5 shows a schematic diagram of fluid flowing under a channel-type ionically resistive element.

[0021] FIG. 6A shows a schematic diagram of a flow circuit of an electroplating apparatus configured for performing neutralization processing of electroplating cells, where each electroplating cell is disposed in a recirculating separated anode chamber (R-SAC) configuration, according to some implementations.

[0022] FIG. 6B shows a schematic diagram of a flow circuit of an electroplating apparatus configured for performing neutralization of electroplating cells, where each electroplating cell is disposed in a cascade separated anode chamber (C-SAC) configuration, according to some implementations.

[0023] FIG. 6C shows a schematic diagram of a flow circuit of an electroplating apparatus configured for performing neutralization of a filter, according to some implementations.

[0024] FIG. 7 shows a flowchart of an exemplary method of performing an electroplating cell neutralization in an R-SAC configuration, according to some implementations.

[0025] FIG. 8 shows a flowchart of an exemplary method of performing an electroplating cell neutralization in a C-SAC configuration, according to some implementations.

[0026] FIG. 9 shows a flowchart of an exemplary method of performing an electroplating cell neutralization, according to some implementations.

[0027] FIG. 10 shows a flowchart of an exemplary method of performing a filter flush, according to some implementations.

[0028] FIG. 11 shows a multi-chamber electroplating apparatus, according to some implementations. DETAILED DESCRIPTION

[0029] The implementations disclosed below can describe processing materials on substrates such as wafers, substrates, or other workpieces. The workpieces can be of various shapes, sizes, and materials. In this application, the terms "semiconductor wafer," "wafer," "substrate," "wafer substrate," and "partially fabricated integrated circuit" are used interchangeably. Those of ordinary skill in the art will appreciate that the term "partially fabricated integrated circuit" can refer to any of a number of stages in the fabrication of an integrated circuit on a silicon wafer. Wafers or substrates used in the semiconductor device industry typically have a diameter of 200 mm, 300 mm, or 450 mm. Unless otherwise specified, processing details described herein, such as flow rates, power levels, etc., are applicable to processing 300 mm diameter substrates, or to processing chambers configured for processing 300 mm diameter substrates, and can be adjusted as appropriate for other sizes of substrates or processing chambers. In addition to semiconductor wafers, other workpieces that can be used in the implementations disclosed herein include a variety of articles, such as printed circuit boards, etc. These processes and apparatuses can be used in the fabrication of semiconductor devices, displays, LEDs, photovoltaic panels, etc.

[0030] Introduction Integrated circuit fabrication often involves depositing one or more layers of electrically conductive metal on a semiconductor wafer. Electroplating processes are a common method of accomplishing such metal layer deposition. Common electroplating applications include, but are not limited to, damascene fill, electrofilling in WLP applications, and electrofilling of TSVs. A variety of metals and metal alloys can be electroplated. These metals or metal alloys can include, but are not limited to, copper, tin, silver, tin-silver alloys, nickel, gold, indium, and cobalt.

[0031] During electroplating, the conductive seed layer (e.g., copper seed layer) on the periphery of the semiconductor wafer is electrically contacted. During a typical electroplating process, the semiconductor wafer containing the exposed conductive seed layer is cathodically biased and contacted with an electroplating solution containing metal ions to be electroplated. The ions are electrochemically reduced at the surface of the seed layer to form a metal layer. The electroplating solution contains an acid, which can provide sufficient electrical conductivity to the electroplating solution. The electroplating solution can also contain additives, such as accelerators, suppressors, and levelers, which can adjust the rate of electrodeposition on different surfaces of the semiconductor wafer.

[0032] An electroplating solution is an electrolyte containing an acid, a metal salt, and other chemicals. The electroplating solution can be highly acidic and hazardous to human health upon exposure. In an electroplating system or apparatus, the electroplating solution is contained not only in a vessel or tank, but also circulated through filters, degassers, electroplating cells, and other hardware components in the electroplating circuit. These hardware components of the electroplating circuit can contain the highly acidic electroplating solution.

[0033] Many of the hardware components in the electroplating circuit can require maintenance from time to time. Such maintenance tasks can include preventative measures, such as process kit replacement or component replacement, or can include unplanned machine or component failures, such as pump or valve failures. In some cases, the anode in the anode compartment of the electroplating cell can need to be replaced on a regular basis. In some cases, the filter in the electroplating circuit can need to be replaced on a regular basis. In some cases, maintenance can be required for pump or valve failures. When performing maintenance on the electroplating system or apparatus, the service engineer or technician can be exposed to hazardous chemicals. The only way to minimize the risk is for the service engineer or technician to wear heavy personal protective equipment (PPE). However, heavy PPE can only be worn for a short period of time, and then a long recovery period is required. Thus, during service of the electroplating system or apparatus, whether replacing a filter or anode, or other maintenance tasks, can require multiple people and / or significant downtime to complete.

[0034] The present disclosure provides a process for neutralizing one or more electroplating cells and other portions of the electroplating circuit for maintenance. As used herein, "neutralizing" refers to a process of bringing a fluid to near neutral pH (i.e., a pH near 7). The process involves mixing or flushing a neutralizing solution with the highly acidic electroplating solution until the pH of the electroplating solution meets a desired safety threshold.

[0035] By performing neutralization on the plating cell or other components, the maintenance engineer or technician can perform maintenance in a short period of time wearing heavy PPE. This short period of time can be just to confirm that the neutralization was successful. Upon confirming that the neutralization was successful, the maintenance engineer or technician can perform various maintenance tasks wearing only standard PPE, if necessary. These tasks can include, but are not limited to, (1) reading / adjusting sensors, (2) removing the top cover, visually inspecting the HRVA, (3) removing the process kit (anode maintenance), and (4) replacing the plating cell filter. Performing neutralization on the acidic chemicals prior to maintenance can reduce human risk, reduce the amount of labor required by the maintenance engineer or technician, and ultimately increase throughput and reduce the cost of ownership. In some cases, neutralization can be performed on selected plating duet / cells so that maintenance can be performed while other plating duets / cells can continue production.

[0036] Electroplating bath and Figure 1 shows a schematic of a flow circuit of a plating apparatus having a plurality of plating cells in fluid communication with an electrolyte reservoir. The plating apparatus 100 can include a reservoir 110, a plating cell 130, a feed line 120 fluidly connecting the reservoir 110 with the plating cell 130, and a return line 160 fluidly connecting the plating cell 130 back to the reservoir 110. A plating solution can be held in the reservoir 110. The plating solution can also be referred to as an electrolyte, plating solution, or process liquid. The reservoir 110 can also be referred to as an electrolyte reservoir, plating cell, plating vessel, or cell. The plating solution is transferred from the reservoir 110 through a pump 104 fluidly connected with the reservoir 110. A cell isolation valve 102 is located between the pump 104 and the reservoir 110, and the cell isolation valve 102 is used to isolate the reservoir 110 from the pump 104. The cell isolation valve 102 controls the flow of the plating solution to the pump 104. The pump 104 drives the plating solution through the feed line 120 fluidly connected with the pump 104 and the plating cell 130.

[0037] The feed line 120 can include a filter 122, where the filter 122 can be used to filter out any particulates in the electroplating solution. The feed line 120 can further include a fluid contactor 124, where the fluid contactor 124 can be used to remove dissolved oxygen or other gases in the circulating electroplating solution. The fluid contactor 124 can include a membrane through which the electroplating solution is driven, where a vacuum port on one side of the filter 122 can draw out the dissolved oxygen or other gases. In some implementations, the feed line 120 can further include a flow meter 126, where the flow meter 126 can be configured to control the flow of liquid therethrough. The feed line 120 can further include a tank isolation valve 128, where the tank isolation valve 128 is used to isolate the electroplating tank 130 from the pump 104. The tank isolation valve 128 controls the flow of electroplating solution to the electroplating tank 130. Along the feed line 120, the filter 122 can be located downstream of the pump 104, the fluid contactor 124 can be located downstream of the filter 122, the flow meter 126 can be located downstream of the fluid contactor 124, and the tank isolation valve 128 can be located downstream of the flow meter 126.

[0038] The electroplating solution flows through the feed line 120 before being split at the T-junction 140. Each outlet of the T-junction 140 enters a separate electroplating tank 130. In some implementations, the electroplating tank 130 is a fountain electroplating tank. Details of each electroplating tank 130 will be described below with reference to FIGS. 3A-3C. Each electroplating tank 130 can include a cathode chamber 132, an ionically resistive element 134, a membrane 136, and an anode chamber 138. The electroplating solution flowing through the cathode chamber 132 and the ionically resistive element 134 can be referred to as a catholyte. The ionically resistive element 134 is proximate to a nearly constant and uniform current source near the substrate (cathode), and thus can be referred to as a high resistance virtual anode (HRVA) or a channeled ionically resistive element (CIRP). The membrane 136 is located below the ionically resistive element 134, where the membrane 136 separates the anode chamber 138 from the cathode chamber 132. The membrane 136 can be an ion-permeable membrane that can block a substantial flow of electrolyte while allowing the transport of cationic ions. The anode chamber 138 contains or houses an anode (e.g., a copper anode or a non-metallic inert anode). The electroplating solution in the anode chamber 138 can be referred to as an anolyte. Typically, the catholyte and the anolyte have different compositions, with the anolyte containing little or no electroplating additives and the catholyte containing a larger concentration of electroplating additives. The anode chamber 138 can also be referred to as a separate anode chamber (SAC).

[0039] As the electroplating solution passes through the electroplating cell 130, the electroplating solution can flow into a collection tank 150. The collection tank 150 can be used to accumulate the electroplating solution before it flows to the reservoir 110. The collection tank 150 can also be referred to as a drain manifold. The collection tank 150 can be used to accumulate the electroplating solution from multiple electroplating cells 130. In some cases, as the electroplating solution is delivered to the electroplating cell 130, the electroplating solution can flow over a weir wall and eventually be provided to the collection tank 150 for collection and recirculation.

[0040] A return line 160 can be fluidically connected to the electroplating cell 130 and the reservoir 110. The return line 160 includes a drain isolation valve 162 configured to isolate the electroplating cell 130 from the reservoir 110. The return line 160 can be fluidically connected to the electroplating cell 130 at the collection tank 150. A level sensor (not shown) can be used to determine the level of fluid in the electroplating cell 130. The level sensor can maintain a target level of fluid in the electroplating cell 130. A signal from the level sensor can be used to adjust the drain isolation valve 162 so that the fluid returning to the reservoir 110 does not bring air bubbles / foam back to the reservoir 110 in an undesirable manner. More particularly, the timing of when the fluid is allowed to reach a certain height in the electroplating cell 130 and be drained back to the reservoir 110 can be monitored so that it is allowed to drop a short distance rather than a long distance. The electroplating solution returning to the reservoir 110 can be used for recirculation through the feed line 120 and the electroplating cell 130.

[0041] In some implementations, the electroplating cell 130 is fluidically connected to an anode chamber tower 152 (also referred to as a "SAC tower"). The anode chamber tower 152 can provide a static head to establish a relatively constant pressure in the anode chamber 138 over a desired period of time, such as during plating and / or during idle periods. In some implementations, the anode chamber tower 152 can be omitted. The anode chamber tower 152 can provide a gas break when fluid is drained from the anode chamber 138 of the electroplating cell 130.

[0042] In the present disclosure, an electroplating system or apparatus is configured for neutralizing one or more selected electroplating cells and / or other components of the electroplating cell circuit in order to enable maintenance with minimal exposure to acidic and hazardous chemicals. The electroplating system or apparatus can include a neutralization flush line (or neutralization fill line) with a neutralization fill valve for delivering a neutralization solution, such as deionized water, to the electroplating cell circuit. One or more selected electroplating cells are isolated for neutralization, where the electrolyte reservoir is isolated from the one or more selected electroplating cells during neutralization. Suction can be performed on the one or more selected electroplating cells to remove residual chemicals, and the one or more selected electroplating cells are filled with the neutralization solution. The process can be repeated until the pH of the solution from the one or more selected electroplating cells reaches a safe threshold. In some cases, the electroplating system or apparatus can isolate a filter for neutralization, and flow the neutralization solution to the filter.

[0043] FIG. 2 shows a schematic diagram of an exemplary flow circuit of an electroplating apparatus with a neutralization flush line bypassing the electrolyte reservoir, according to some implementations. Some aspects of the electroplating apparatus of FIG. 1, such as the return line 160, the electroplating cells 130, the feed line 120, the reservoir 110, the pump 104, the filter 122, and the fluid contactor 124, are included in the electroplating apparatus of FIG. 2 and are not repeated for brevity.

[0044] The neutralization flush line 210 is fluidly connected to the electroplating cells 130 and the pump 104. The neutralization flush line 210 includes a neutralization fill valve 212 configured to provide a neutralization solution to the pump 104 and circulate the neutralization solution through the feed line 120 and the electroplating cells 130. In some implementations, the neutralization solution is water or deionized water. In other implementations, the neutralization solution contains a base or other non-acidic chemical.

[0045] The neutralization flush line 210 can be fluidly connected to the electroplating tank 130 at the collection tank 150. Alternatively, the neutralization flush line 210 can be fluidly connected to the electroplating tank at the return line 160 before (e.g., upstream of) the drain isolation valve 162. The neutralization flush line 210 bypasses the reservoir return line 164 and the reservoir 110. In some implementations, the neutralization flush line 210 can circulate the electroplating solution back to the electroplating tank 130 through the pump 104 and the feed line 120. In some alternative implementations, the neutralization flush line 210 can circulate and recirculate the neutralization solution back to the electroplating tank 130 through the pump 104 and the feed line 120. The neutralization flush line 210 can further include a recirculation valve 214 configured to recirculate the electroplating solution, the neutralization solution, or a mixture thereof directly from the electroplating tank 130 to the pump 104. In this way, the recirculation valve 214 and the neutralization flush line 210 provide a fluid source to the pump 104, unlike the reservoir 110. The recirculation valve 214 can provide fluid (e.g., the electroplating solution, the neutralization solution) to the electroplating tank 130 at a desired flow rate, such as between about 20 liters per minute to about 150 liters per minute, between about 30 liters per minute to about 100 liters per minute, or between about 40 liters per minute to about 80 liters per minute, through the pump 104.

[0046] The neutralization flush line 210 can be divided into two parts: (a) a bypass return line 210a fluidly connected to the electroplating tank 130, and (b) a neutralization fill line 210b fluidly connected to the pump 104. Rather than flowing back to the reservoir 110 through the return line 160, fluid can be circulated from the electroplating tank 130 to the bypass return line 210a. Fluid can flow from the bypass return line 210a to the neutralization fill line 210b by controlling the recirculation valve 214. The neutralization solution can flow from the neutralization fill valve 212 to the neutralization fill line 210b to provide the neutralization solution to the electroplating tank 130.

[0047] In some implementations, the neutralization flush line 210 further includes a drain valve 216. During normal electroplating, the recirculation valve 214 remains closed to enable normal circulation of the electroplating solution through the reservoir 110 and the pump 104. This causes fluid above the recirculation valve 214 to stagnate, which adversely affects the concentration of the electroplating solution. During normal electroplating, the recirculation valve 214 does not need to be periodically opened, and the drain valve 216 can allow the portion of fluid trapped above the recirculation valve 214 to drain into the electroplating solution. This allows the trapped fluid to maintain a concentration such that it does not stagnate. In some implementations, the drain valve 216 can flow the trapped fluid above the recirculation valve 214 to the pump 104 at a desired flow rate, such as about 0.1 liters per minute to about 5 liters per minute, about 0.5 liters per minute to about 3 liters per minute, or about 1 liter per minute to about 2 liters per minute.

[0048] Before delivering the neutralization solution to the electroplating cell 130, the electroplating cell 130 can be pumped to evacuate residual chemicals from the electroplating cell 130 and the feed line 120. The liquid can be removed from the electroplating cell circuit by pumping, rather than returning the liquid to the reservoir 110 or recirculating the liquid to the electroplating cell 130. In some implementations, the neutralization flush line 210 also includes a main body pump-out valve 218 that is connected to a pump-out line (not shown) and a main body pump-out pump (not shown) for removing fluid from the electroplating cell circuit. In some implementations, the filling of the electroplating cell circuit can be accomplished using the neutralization fill valve 212, and the pumping of the electroplating cell circuit can be accomplished using the main body pump-out valve 218. The neutralization fill valve 212 can provide the neutralization solution at a desired flow rate, such as between about 3 liters per minute and about 40 liters per minute, between about 5 liters per minute and about 30 liters per minute, or between about 10 liters per minute and about 20 liters per minute. The main body pump-out valve 218 can pump at a similar rate.

[0049] FIG. 3A shows a schematic diagram of an exemplary flow circuit of an electroplating apparatus having a drain line that bypasses an electrolyte reservoir, according to some implementations. Some aspects of the electroplating apparatus of FIG. 1, such as the return line 160, the electroplating cell 130, the feed line 120, the reservoir 110, the pump 104, the filter 122, and the fluid contactor 124, are included in the electroplating apparatus of FIG. 3A and are not repeated for the sake of brevity.

[0050] In the electroplating apparatus of FIG. 3A, the drain line 310 can be fluidly connected to the electroplating cell 130 at the collection tank 150. Alternatively, the drain line 310 can be fluidly connected to the return line 160 before (e.g., upstream of) the drain isolation valve 162. The drain line 310 bypasses the reservoir return line 164 and the reservoir 110. The drain line 310 can include a drain valve 312, where the drain valve 312 is configured to control the flow of the electroplating solution, the neutralization solution, or a mixture thereof from the drain line 310 to the waste 314. Thus, fluid can flow through the electroplating cell 130 and directly to the waste 314 through the drain line 310. This bypasses the reservoir return line 164 for returning fluid to the reservoir 110. This also bypasses the bypass return line 210a for recirculating fluid through the feed line 120 and the electroplating cell 130. In such a case, gravity can assist in the flow of fluid through the drain line 310 to the waste 314, as residual chemicals can be heavier than the fluid and more easily pushed to the waste 314. The flow circuit of the electroplating apparatus of FIG. 3A can or can not include the bypass return line 210a for fluid recirculation.

[0051] The neutralization fill valve 212 is configured to provide a neutralization solution to the electroplating cell 130. In FIG. 2, the neutralization fill valve 212 can be located downstream of the electroplating cell 130 and provide the neutralization solution to the electroplating cell 130 through the pump 104 and the feed line 120. However, in FIG. 3A, the neutralization fill valve 212 and the neutralization fill line 210b can be located upstream of the electroplating cell 130 and provide the neutralization solution directly to the electroplating cell 130. In fact, the neutralization fill valve 212 can be located anywhere in the flow circuit that provides the neutralization solution to the electroplating cell 130 and can be disposed along the feed line 120 or the bypass return line 210a, among others.

[0052] FIG. 3B shows a schematic diagram of an alternative flow circuit of an electroplating apparatus having a drain line that bypasses the electrolyte reservoir, according to some implementations. Some aspects of the electroplating apparatus of FIG. 1, such as the return line 160, the electroplating cell 130, the feed line 120, the reservoir 110, the pump 104, the filter 122, and the fluid contactor 124, are included in the electroplating apparatus of FIG. 3B and are not repeated for the sake of brevity.

[0053] In the electroplating apparatus of FIG. 3B, the drain line 310 can be fluidly connected to the feed line 120. In fact, the drain line 310 can be located anywhere in the flow circuit that drains the electroplating solution, the neutralization solution, or a mixture thereof. For example, the drain line 310 can be fluidly connected to the feed line 120 at the filter 122. In such a case, the flow can be reversed such that fluid flows from the electroplating cell 130 to the feed line 120 and through the fluid contactor 124 and the filter 122. The drain line 310 can include a drain valve 312, where the drain valve 312 is configured to control the flow of the electroplating solution, the neutralization solution, or a mixture thereof from the drain line 310 to the waste 314.

[0054] FIG. 3C shows a schematic diagram of an alternative flow circuit of an electroplating apparatus, according to some implementations. Some aspects of the electroplating apparatus of FIG. 1, such as the return line 160, the electroplating cell 130, the feed line 120, the reservoir 110, the pump 104, the filter 122, and the fluid contactor 124, are included in the electroplating apparatus of FIG. 3C and are not repeated for the sake of brevity.

[0055] The electroplating apparatus includes a return line 160 fluidly coupled with the electroplating tank 130. In some implementations, the return line 160 is also fluidly coupled with one or more of: (1) a reservoir return line 164 fluidly coupled with the reservoir 110, (2) a bypass return line 210a fluidly coupled with the pump 104 that bypasses the reservoir 110, and (3) a drain line 310 that leads to the waste section 314. In some implementations, the electroplating apparatus includes only the drain line 310 fluidly connected with the return line 160. In some implementations, the electroplating apparatus includes only the bypass return line 210a fluidly connected with the return line 160. In some implementations, the electroplating apparatus includes both the bypass return line 210a fluidly coupled with the return line 160 and the reservoir return line 164 fluidly coupled with the return line 160. In some implementations, the electroplating apparatus includes both the bypass return line 210a fluidly coupled with the return line 160 and the drain line 310 fluidly coupled with the return line 160. In some implementations, the electroplating apparatus includes the bypass return line 210a, the drain line 310, and the reservoir return line 164 fluidly coupled with the return line 160.

[0056] The plating apparatus configurations in FIGS. 2 and 3A-3C are illustrative and not limiting to the scope of the disclosure. Other configurations of plating apparatuses can be designed for use in and with electroplating cells. A plating apparatus, as shown in FIGS. 2 and 3A-3C, can include a reservoir (e.g., reservoir 110) configured to hold an electroplating solution. The plating apparatus can further include a pump (e.g., pump 104) having an outlet and an inlet. The plating apparatus further includes one or more electroplating cells (e.g., electroplating cell 130), where each of the one or more electroplating cells includes a cathode chamber (e.g., cathode chamber 132), an anode chamber (e.g., anode chamber 138) configured to hold an anode, and a separator (e.g., separator 136) between the cathode chamber and the anode chamber. In some cases, each of the one or more electroplating cells can further include an ionically resistive element (e.g., ionically resistive element 134) above the separator. The plating apparatus also includes a feed line (e.g., feed line 120) fluidly coupled to the pump outlet and to the one or more electroplating cells. The plating apparatus also includes a return line (e.g., return line 160) fluidly coupled to the one or more electroplating cells. The return line can also be fluidly coupled to one or more of: (1) a reservoir return line (e.g., reservoir return line 164) fluidly coupled to the reservoir; (2) a bypass return line (e.g., bypass return line 210a) that bypasses the reservoir and is fluidly coupled to the pump; and (3) a drain line (e.g., drain line 310) to a waste section (e.g., waste section 314). The plating apparatus further includes a neutralization fill line (e.g., neutralization fill line 210b) fluidly coupled to the one or more electroplating cells and configured to provide a neutralization solution to the one or more electroplating cells. In some implementations, the neutralization solution includes deionized water. In some implementations, the neutralization solution includes a base. In some implementations, the inlet of the pump is fluidly coupled to the bypass return line and the reservoir output line. In some implementations, the return line is fluidly coupled to the drain line, where the neutralization fill line is configured to circulate the neutralization solution through the one or more electroplating cells and to the drain line via the return line. In some implementations, the return line is fluidly coupled to the bypass return line, where the neutralization fill line is configured to circulate the neutralization solution through the one or more electroplating cells and the bypass return line and via the pump and the feed line. The plating apparatus can use the neutralization fill line to perform a process to draw and / or flush a selected one or more of the electroplating cells with the neutralization solution until a pH of the selected one or more of the electroplating cells reaches a safe threshold. Additionally, the plating apparatus can also use the neutralization fill line to perform a process to draw and / or flush a filter with the neutralization solution until a pH of the filter reaches a safe threshold.

[0057] Filling and pumping of some areas in the electroplating cell can present challenges. For example, filling and pumping of the area formed by the ionically resistive element 134, the diaphragm 136, and the diaphragm frame (not shown) that supports the diaphragm 136 can be difficult. Filling such an area, referred to as an "HRVA chamber," can be assisted by the recirculation valve 214, which is capable of flowing a neutralizing solution to the electroplating cell 130 at a sufficiently high flow rate. Pumping of such an area can be assisted by the HRVA chamber pump-down valve 220. The HRVA chamber pump-down valve 220 can be fluidically coupled to the HRVA chamber by a pump-down line 222. In some implementations, the pump-down line 222 can include a suction tube that is attached to a sidewall of the diaphragm frame. The HRVA chamber pump-down valve 220 can be connected to the pump-down line 222 and a HRVA chamber pump-down pump (not shown) for evacuating fluid from the HRVA chamber. Other methods, techniques, and components for effective filling and pumping strategies for the HRVA chamber of the electroplating cell 130 are discussed in further detail below.

[0058] FIG. 4A shows a schematic diagram of an exemplary electroplating cell that utilizes a combination of a cross-flow and an impingement flow on the substrate surface during electroplating. In the electroplating cell 401, a substrate 402 is positioned in a substrate support 403. The substrate support 403 is often referred to as a cup, and can support the substrate 402 at its periphery. An anode 404 is positioned near the bottom of the electroplating cell 401. The anode 404 is separated from the substrate 402 by a diaphragm 405, which is positioned below the substrate 402 and is supported by a diaphragm frame 406. The diaphragm frame 406 is sometimes referred to as an anode-chamber diaphragm frame. In addition, the anode 404 is separated from the substrate 402 by an ionically resistive element 407. The ionically resistive element 407 includes openings that allow electrolyte to pass through the ionically resistive element 407 to impinge on the substrate 402. A front-side insert 408 is positioned above the ionically resistive element 407, near the periphery of the substrate 402. As shown, the front-side insert 408 can be arcuate or annular, or can be azimuthally non-uniform. The front-side insert 408 is sometimes also referred to as a cross-flow restriction ring. An annular or arcuate seal 416 is provided between the front-side insert 408 and the substrate support 403.

[0059] An anode compartment 412 is located below the separator 405 and is where the anode 404 is located. An ionically resistive element manifold 411 is located above the separator 405 and below the ionically resistive element 407. A lateral flow manifold 410 is located above the ionically resistive element 407 and below the substrate 402. The height of the lateral flow manifold 410 is the distance between the substrate 402 and the plane of the ionically resistive element 407 (not including the ribbing on the top surface of the ionically resistive element 407, if present). In some cases, the lateral flow manifold 410 can have a height of between about 1 mm and about 4 mm, or between about 0.5 mm and about 15 mm. The sides of the lateral flow manifold 410 are defined by a front side insert 408, which functions to contain the lateral flow electrolyte within the lateral flow manifold 410. Side inlet 413 and side outlet 414 of the lateral flow manifold 410 are oppositely disposed in azimuthal angle. The side inlet 413 and side outlet 414 can be at least partially formed by the front side insert 408. A seal 416 provides a seal between the front side insert 408 and the substrate support 403, thereby ensuring that electrolyte only flows out of the lateral flow manifold 410 through the side outlet 414 when the seal 416 is engaged. In various cases, the seal 416 can be integrally formed with the lateral flow restriction ring or the substrate support 403, or can be provided as a separate unit.

[0060] As shown by the arrows in FIG. 4A, electrolyte enters the lateral flow manifold 410 through the side inlet 413 and exits the lateral flow manifold 410 through the side outlet 414. Additionally, electrolyte can enter the ionically resistive element manifold 411 through one or more inlets (not shown), enter the ionically resistive element manifold 411, pass through the openings in the ionically resistive element 407, enter the lateral flow manifold 410, and exit through the side outlet 414. After passing through the side outlet 414, the electrolyte spills over the weir 409. The electrolyte can be recovered and reused. The electrolyte that flows through the ionically resistive element manifold 411, the ionically resistive element 407, the side inlet 413, the lateral flow manifold 410, and the side outlet 414 can be referred to as cathode electrolyte. In addition to the cathode electrolyte flow, a separate anode electrolyte flow is typically provided. The electrolyte that is in contact with the anode during the cycle can be referred to as anode electrolyte. The separator 405 functions to separate the cathode electrolyte and the anode electrolyte from each other, ensuring that the respective compositions are maintained, while allowing ions to be transported through the mechanism during electroplating. The anode compartment 412 includes an inlet (not shown) for receiving anode electrolyte and an outlet (not shown) for removing anode electrolyte from the anode compartment 412. The inlet and outlet of the anode compartment 412 can be connected to an anode electrolyte recirculation system.

[0061] As noted above, the ionically resistive element 407 approximates an almost constant and uniform current source near the substrate, and thus can be referred to as an HRVA or CIRP in some cases. The ionically resistive element 407 is typically placed close to the substrate. The ionically resistive element 407 includes small-sized (typically less than 0.04 inch) through-holes that are spatially and ionically isolated from each other and do not form interconnected channels within the body of the ionically resistive element 407, as is the case in many, but not all, implementations. Such through-holes are typically referred to as non-flowing through-holes. They typically extend in one dimension, usually (but not necessarily) perpendicular to the electroplated surface of the wafer (in some implementations, the non-flowing through-holes are at an angle to the wafer, typically parallel to the front surface of the ionically resistive element). The through-holes are typically parallel to each other. In other cases, they are laid out in a biased spiral pattern. These through-holes are distinguished from 3-D porous networks (in which channels extend in three dimensions and form an interconnected pore structure) in that they re-direct the ion current flow and (in some cases) the fluid flow parallel to the surface in which they are embedded, and straighten the path of the current and fluid flow to the substrate surface. However, in some implementations, such porous plates with interconnected pore networks can be used as ionically resistive elements. When the distance from the top surface of the plate to the substrate is small (e.g., the gap is on the order of 1 / 10 of the substrate radius dimension, e.g., less than about 5 mm), the divergence of the current and fluid flow is locally limited, and is conducted to and aligned with the ionically resistive element channels.

[0062] The ionically resistive element 407 can optionally include a series of linear ribs 415 that protrude out of / in the page. The ribs 415 are sometimes referred to as protrusions. The ribs 415 are located on the top surface of the ionically resistive element 407, and their direction is such that their length (as the longest dimension) is perpendicular to the direction of the lateral flow of the electrolyte. The ribs 415 affect the fluid flow and current distribution within the lateral flow manifold 410. For example, the lateral flow of the electrolyte is primarily confined to the area above the top surface of the ribs 415, resulting in a higher rate of lateral flow of the electrolyte. In the areas between adjacent ribs 415, the current that is transported upward through the ionically resistive element 407 before being delivered to the substrate surface is redistributed, becoming more uniform.

[0063] In FIGS. 4A and 4B, the direction of lateral flow of electrolyte is from left to right (e.g., from side inlet 413 to side outlet 414), and the direction of ribs 415 is such that their length extends into / out of the page. As shown in FIG. 4A, ribs 415 can be provided in a region that is substantially the same width as the substrate. Channels / openings in ionically resistive element 407 can be provided between adjacent ribs 415, or can extend through ribs 415 (in other words, ribs 415 can or can not have channels). In other implementations, ionically resistive element 407 can have a flat upper surface (e.g., not including ribs 415). In other implementations, ribs 415 can be replaced with raised plateau regions.

[0064] FIG. 4B shows a cross-sectional view of various hardware components in the plating cell. Plating cell 401 includes a cathode chamber 432, which includes a separator frame 406 and a separator 405 that separates an anode chamber 412 from cathode chamber 432. Separator 405 is typically an ion exchange membrane that separates anode chamber 412 from cathode chamber 432. Separator frame 406 is a structural element for supporting separator 405. Fluid in cathode chamber 432 is mostly in lateral flow manifold 410 or ionically resistive element manifold 411, or in channels that transport fluid to these two separate manifolds.

[0065] Fluid can enter lateral flow manifold 410 through two separate entry points: (1) channels in ionically resistive element 407 and (2) lateral flow initiation structure 450. Fluid (e.g., catholyte) that enters lateral flow manifold 410 through channels in ionically resistive element 407 can be directed (typically in a substantially perpendicular direction) toward the surface of the workpiece. Such channel-delivered fluid can form a small jet that impinges on the workpiece surface. In contrast, fluid that enters lateral flow manifold 410 through lateral flow initiation structure 450 is substantially parallel to the workpiece surface. Lateral flow jet manifold 422 directs fluid vertically upward into lateral flow initiation structure 450, which reorients the fluid to be parallel or substantially parallel to the substrate in lateral flow manifold 410. Fluid that exits lateral flow manifold 410 can exit from lateral flow outlet 434.

[0066] Figure 4C shows an isometric cutaway view of an electroplating cell including a high resistance virtual anode (HRVA) chamber. As described above, fluid can be delivered into the lateral flow manifold 410 of the cathode chamber 432 through at least two different flow paths. Some fluid can be delivered through the channels in the ionically resistive element 407. Some fluid can be delivered to the lateral flow jet manifold 422, which then delivers fluid to the lateral flow initiation structure 450. The lateral flow initiation structure 450 has a geometry that can redirect fluid into a direction that is parallel or substantially parallel to the substrate. The direction of fluid flow through the ionically resistive element 407 is initially toward the substrate, and then turns to be parallel to the substrate due to the presence of the substrate, while the lateral flow portion from the lateral flow jet manifold 422 and out of the lateral flow initiation structure 450 starts from a direction that is substantially parallel to the substrate.

[0067] The area below the ionically resistive element 407 is defined by the ionically resistive element 407, the septum 405, and the septum frame 406. This area is referred to as the HRVA chamber 460. The area referred to as the HRVA chamber 460 is difficult to fill and aspirate. When fluid enters the lateral flow manifold 410 through the lateral flow jet manifold 422 and the lateral flow initiation structure 450, the fluid flows horizontally over the top of the ionically resistive element 407. When a substrate is positioned in the electroplating cell 401, there is a resulting pressure in the electroplating cell 401 that forces an amount of fluid to flow along the ionically resistive element 407 into the HRVA chamber 460. It can require a sufficiently high flow rate of fluid through the ionically resistive element 407 to fill the HRVA chamber 460, such as a flow rate of between about 20 liters per minute and 150 liters per minute, between about 30 liters per minute and 100 liters per minute, or between about 40 liters per minute and 80 liters per minute.

[0068] As shown in Figure 5, when fluid flows through the ionically resistive element 407 while a substrate is positioned, a pressure is created that forces fluid to flow along the channel 417 into the HRVA chamber 460. As the fluid is forced down through the channel 417, a vortex is created in the HRVA chamber 460 that causes the fluid to flow back. The vortex associated with the fluid flow can create an effective flushing action for flushing the septum 405, the septum frame 406, and the ionically resistive element 407. In the electroplating cell and during the electroplating process, the positioning of a substrate into the electroplating cell 401 can create sufficient pressure to create a vortex for flushing the area below the ionically resistive element 407, i.e., the HRVA chamber 460.

[0069] The electroplating cells of the present disclosure and can be configured for different types of split anode compartment configurations. One type of split anode compartment configuration is a recirculating split anode compartment (R-SAC) configuration. Another type of split anode compartment configuration is a cascading split anode compartment (C-SAC). However, it should be understood that the electroplating cells are not limited to these configurations. The R-SAC configuration is typically used for tin, tin silver, and nickel electroplating applications. The C-SAC configuration is typically used for copper electroplating applications. The R-SAC configuration typically uses a polymeric based separator, which is tough and resistant to pressure differentials within the range of the polymeric based separator. The C-SAC configuration typically uses a cationic separator, which is soft and less resistant to pressure differentials within the range of the cationic separator. As a result, the behavior and characteristics of the different SAC configurations can require different approaches to fill and pump the SAC. The SAC can require its own circuit for purging, flushing, and pumping, which is independent of the electroplating cell circuit. As a result, the neutralization strategy and sequence of the R-SAC configuration can be different from the C-SAC configuration.

[0070] FIG. 6A shows a schematic diagram of a flow circuit of an electroplating apparatus configured to perform neutralization of electroplating cells, where each electroplating cell is disposed in a recirculating split anode compartment (R-SAC) configuration, according to some implementations. In the R-SAC configuration, the anode compartment contains the same fluid as the electroplating cell. In the R-SAC configuration, the neutralization of the anode compartment is integrated with the main electroplating circuit. In other words, the neutralization solution that is circulated through the electroplating cell is also used to flush the anode compartment.

[0071] In the R-SAC configuration as shown in FIG. 6A, the anode compartment 138 receives the neutralization solution (or plating solution) from a pressurized line 642 outside the plating tank circuit. The line 642 is pressurized when the pump 104 is on. The line 642 is fluidly connected to the feed line 120. The flow of the neutralization solution (or plating solution) into the anode compartment 138 is directly proportional to the plating tank flow rate. To achieve a higher flow rate into the anode compartment 138, a first R-SAC valve 644 is used in conjunction with a second R-SAC valve 646. The first R-SAC valve 644 and the second R-SAC valve 646 are in parallel to serve as a source of fluid that is tapped off from the feed line 120. The first R-SAC valve 644 and the second R-SAC valve 646 deliver fluid from the feed line 120 to the anode compartment 138. After the fluid passes through the anode compartment 138 into the anode compartment tower 152, the fluid can be gravity drained using an R-SAC drain line 648. A diverter valve 654 can be fluidly connected to the R-SAC drain line 648. The diverter valve 654 can allow the fluid to return to the reservoir 110 during normal plating operation and can drain the fluid from the reservoir 110 during neutralization. In some implementations, the diverter valve 654 can be a 3-way valve. The suction of the anode compartment 138 can be assisted by an anode compartment suction valve 656. The anode compartment suction valve 656 is fluidly connected to the anode compartment 138 through an anode compartment suction line 658. In some implementations, the anode compartment suction valve 656 can be connected to the anode compartment suction line 658 and a HRVA / SAC suction pump 662. The HRVA / SAC suction pump 662 can be configured to evacuate fluid from the HRVA compartment and the anode compartment 138.

[0072] In FIG. 6A, the neutralization flush line 210 can optionally include a precursor dosing valve 664. The precursor dosing valve 664 can be fluidly coupled to the pump 104 and the feed line 120. The precursor dosing valve 664 can be configured to dose a precursor to the plating tank 130. For example, the precursor can include a chemical such as methane sulfonic acid (MSA) that can prevent precipitation when the neutralization solution is mixed with the plating solution. Such precipitation can occur in the case of tin, tin silver, and nickel plating solutions. The precursor can be delivered to the plating tank circuit after the plating solution is circulated in the plating tank 130 and before the neutralization solution is delivered to the plating tank 130.

[0073] FIG. 6B shows a schematic diagram of a flow circuit of a plating apparatus configured to perform neutralization of plating tanks, where each plating tank is disposed in a cascading separate anode compartment (C-SAC) configuration, according to some implementations. In the C-SAC configuration, the anode compartments are filled and suctioned in their own circuit that is independent of the plating tank circuit. In the C-SAC configuration, the anode compartments do not necessarily contain the same fluid as the main plating tank. The neutralization of the anode compartments is performed by recirculating the neutralization solution in the SAC circuit that is independent of the plating tank circuit.

[0074] In the C-SAC configuration shown in FIG. 6B, a separate source of neutralizing solution is provided for the anode compartment 138. In the C-SAC configuration, the C-SAC pump 672 draws fluid from the anode compartment tower 152 and drives the fluid through the flow meter 674 and into the anode compartment 138. The anode compartment 138 is fluidly coupled to the anode compartment tower 152 such that the fluid is recirculated through the SAC loop that is separate from the electroplating cell loop. To fill the anode compartment 138, a diverter valve 676 is added just downstream of the C-SAC pump 672 to interrupt the SAC loop and enable it to be filled with a neutralizing solution. A second neutralizing fill valve 678 is provided at the diverter valve 676. The second neutralizing fill valve 678 is separate from the neutralizing fill valve 212 to provide a separate source of neutralizing solution for the anode compartment 138. The second neutralizing fill valve 678 is configured to provide a neutralizing solution, such as deionized water, through the flow meter 674 and to the anode compartment 138 and the anode compartment tower 152. The C-SAC pump 672 can recirculate the neutralizing solution from the anode compartment tower 152 back to the input side of the C-SAC pump 672. When the anode compartment tower 152 reaches a certain level, the neutralizing fill valve 678 can be closed and the diverter valve 676 will open. At this point, the C-SAC pump 672 can be turned on to recirculate the neutralizing solution. This series of operations can cause air bubbles to become trapped in the SAC loop. In some implementations, a drain valve 682 can be configured to bleed fluid at the input side of the C-SAC pump 672 to remove air bubbles that can become trapped in the SAC loop. Repeatedly opening the neutralizing fill valve 678 and the drain valve 682 can purge and prime the SAC loop. In some implementations, a suction valve (not shown) can be connected to the input side of the C-SAC pump 672 and the HRVA / SAC suction pump 662. The HRVA / SAC suction pump 662 can be configured to evacuate fluid from the anode compartment tower 152, the C-SAC pump 672, and the flow meter 674.

[0075] In FIG. 6B, as in FIG. 6A, the anode compartment 138 can be assisted in being evacuated by the anode compartment evacuation valve 656. The anode compartment evacuation valve 656 is fluidly connected to the anode compartment 138 by the anode compartment evacuation line 558. In some implementations, the anode compartment evacuation valve 656 can be connected to the anode compartment evacuation line 658 and the HRVA / SAC suction pump 662. The HRVA / SAC suction pump 662 can be configured to evacuate fluid from the HRVA chamber and the anode compartment 138.

[0076] In the C-SAC configuration, the evacuation of the anode compartment 138 can follow a particular sequence. For example, the HRVA chamber can be evacuated before the anode compartment 138. This can avoid exerting too much pressure on the septum 136, which is typically softer in the C-SAC configuration. Furthermore, in the C-SAC configuration, the filling of the anode compartment 138 can follow a particular sequence. For example, the anode compartment 138 can be filled before the HRVA chamber.

[0077] In neutralizing one or more selected plating cells, adhering to a specific sequence of steps can be critical to the success of the neutralization. The steps in the plating cell loop can differ from the steps in the SAC loop. This is due in part to the rinse, fill, and pump-down behavior in the HRVA / anode compartment differing from the rinse, fill, and pump-down behavior in the main body plating cell. The hardware control of the rinse, fill, and pump-down of the HRVA / anode compartment during neutralization can also differ from the hardware control of the rinse, fill, and pump-down of the main body plating cell. In addition, the sequence of steps in the plating cell loop during neutralization can depend on activities in the SAC loop and vice versa. The sequence of steps in the plating cell loop and the SAC loop for the R-SAC configuration is shown in FIG. 7. The sequence of steps in the plating cell loop and the SAC loop for the C-SAC configuration is shown in FIG. 8.

[0078] FIG. 7 shows a flowchart of an exemplary method of performing plating cell neutralization in a plating cell in an R-SAC configuration, according to some implementations. The system controller described below can be configured with instructions to perform the various operations of FIG. 7. The operations of FIG. 7 can be performed using the hardware components described in FIGS. 1, 2, 3A-3C, 4A-4C, and 6A-6C.

[0079] Plating cell neutralization can be initiated by isolating one or more plating cells. One or more plating cells are selected for neutralization. The selected plating cells can be dual cells in a plating system or apparatus. The plating cells can be neutralized asynchronously. While the plating metal is being plated on wafers in non-selected plating cells, the selected plating cells can be neutralized. This means that while the selected plating cells are being neutralized for maintenance, the plating metal can be plated in one or more plating cells that are not selected for neutralization.

[0080] Referring to FIG. 6A, the selected plating cell 130 can be isolated from the reservoir 110 by closing the drain isolation valve 162. In some implementations, the selected plating cell 130 can be isolated or further isolated from the pump 104 by closing the cell isolation valve 102, thereby isolating the reservoir 110 from the pump 104. In some implementations, the selected plating cell 130 can be isolated or further isolated from the reservoir 110 by closing the diverter valve 654, thereby isolating the anode compartment 138 from the reservoir 110. The plating cell loop is now completely isolated from the reservoir 110.

[0081] In some implementations, chemical recovery can be performed before or after isolating the selected one or more plating cells. Chemical recovery can recover as much chemical as possible from the plating cell loop. Gravitational chemical recovery can be performed before active chemical recovery, thereby bringing residual chemicals in the plating cell loop back to the reservoir.

[0082] Referring to FIG. 6A, chemical recovery can be performed by opening the drain isolation valve 162 to recover residual chemicals (e.g., electrolyte) in the return line 160 and the plating cell 130 to the reservoir 110. Additionally, the cell isolation valve 128 can also be opened to recover residual chemical in the feed line 120 to the reservoir 110 while the drain isolation valve 162 remains open.

[0083] In some implementations, chemical recovery can be performed after isolating the selected one or more plating cells. Active chemical recovery can be performed by providing one or more gases through the feed line, filter, fluid contactor, or other hardware components to bring residual chemicals back to the reservoir. For example, the one or more gases include nitrogen.

[0084] Referring to FIGS. 6A and 6C, active chemical recovery can be performed after isolating the one or more plating cells 130. The nitrogen gas supply valve 680 can be opened to allow nitrogen gas to enter the reservoir 110 through the feed line 120. In doing so, the filter flush valve 690, which is fluidly coupled to the reservoir 110, is opened. The nitrogen gas can pass through the fluid contactor 124 and the filter 122 to recover residual chemicals in the fluid contactor 124 and / or the filter 122 to the reservoir 110.

[0085] After isolating the selected one or more plating cells, the selected one or more plating cells are pumped down. Pumping down can remove any residual chemicals in the body plating cell. This can be achieved by the body pump down valve and the body pump down pump, which are fluidly coupled to the selected one or more plating cells. Pumping down can also remove any residual chemicals in the HRVA chamber and the anode chamber. Pumping down of the HRVA chamber can be accomplished by the HRVA chamber pump down valve and the HRVA / SAC pump down pump, which are fluidly connected to the HRVA chamber. Pumping down of the anode chamber can be achieved by the HRVA / SAC pump down pump, which is fluidly connected to the anode chamber.

[0086] Referring to FIG. 6A, pumping down can be performed by opening the body pump down valve 218. Additionally, the cell isolation valve 128 and the recirculation valve 214 are opened to facilitate pumping down the selected one or more plating cells 130. This enables pumping down of the recirculation loop. While the recirculation loop is being pumped down by opening the body pump down valve 218, pumping down of the HRVA chamber can be initiated by opening the HRVA chamber pump down valve 220. When the HRVA chamber is pumped down, the HRVA chamber pump down valve 220 is closed, and pumping down of the anode chamber 138 can be initiated by opening the anode chamber pump down valve 656. When the anode chamber 138 is pumped down, the anode chamber pump down valve 656 is closed.

[0087] After the one or more electroplating cells are selected for pumping, the selected one or more electroplating cells are filled with a neutralizing solution (e.g., deionized water). During the filling of the neutralizing solution, the neutralizing fill valve is opened to provide the neutralizing solution to the selected one or more electroplating cells. The fill rate of the main electroplating cell can be different (e.g., faster) than the anode compartment. The anode compartment can be only partially filled when the electroplating cell loop is full of the neutralizing solution. The level monitoring system can determine that the electroplating cell loop is full. After the electroplating cell loop is determined to be full, recirculation can be initiated to recirculate the neutralizing solution in the electroplating cell loop. During this time, the anode compartment can be eventually filled. The anode compartment can be drained and fed to prevent solution buildup and to continuously flush the anode compartment with the neutralizing solution.

[0088] Referring to FIG. 6A, the filling can be performed by opening the neutralizing fill valve 212. This provides the neutralizing solution (e.g., deionized water) through the pump 104 to the feed line 120, which flows to the selected one or more electroplating cells 130. At the same time, the first R-SAC valve 644 and the second R-SAC valve 646 are opened to provide the neutralizing solution from the line 642 to the anode compartment 138. Once the selected one or more electroplating cells 130 are full, the recirculation valve 214 can be opened to recirculate the neutralizing solution through the electroplating cell loop. The anode compartment 138 can be filled at a slower rate. Once the anode compartment 138 is full, the neutralizing solution will continue to flow out of the anode compartment tower 152 and to the drain via the drain diverter valve 654 while delivering additional neutralizing solution to the anode compartment 138.

[0089] In some implementations, a precursor charge is provided to the electroplating cell loop prior to filling the electroplating cell loop with the neutralizing solution. In some cases, the neutralizing solution can cause unwanted chemical precipitation of the electroplating solution in the electroplating cell loop. Therefore, prior to filling, a precursor charge can be delivered to the selected one or more electroplating cells by opening the precursor dosing valve. In some implementations, the precursor is MSA.

[0090] Referring to FIG. 6A, the precursor charge can be delivered to the selected one or more electroplating cells 130 by opening the precursor dosing valve 664. The precursor dosing valve 664 can be opened after the selected one or more electroplating cells 130 are pumped and prior to filling the selected one or more electroplating cells 130 with the neutralizing solution.

[0091] After the pumping and filling, a pH check can be performed to determine the pH of the solution of the selected one or more electroplating cells. If the pH of the solution meets a safety threshold, the neutralization is complete and maintenance can be performed. If the pH of the solution does not meet the safety threshold, at least the pumping and filling process of another cycle is repeated. In some implementations, the number of cycles can be between about 3 cycles and about 50 cycles, about 5 cycles and about 30 cycles, or about 10 cycles and about 20 cycles. In some implementations, the safety threshold can be a pH between about 3 and about 10, about 4 and about 9, or about 5 and about 8. In some cases, the pH can be manually measured by opening the door of the selected one or more electroplating cells and / or removing the top cover.

[0092] FIG. 8 shows a flowchart of an example method of performing electroplating cell neutralization of electroplating cells in a C-SAC configuration, according to some implementations. A system controller as described below can be configured with instructions to perform the various operations of FIG. 8. The operations of FIG. 8 can be performed using the hardware components described in FIGS. 1, 2, 3A-3C, 4A-4C, and 6A-6C.

[0093] Electroplating cell neutralization can be initiated by isolating one or more electroplating cells. One or more electroplating cells are selected for neutralization. The selected electroplating cells can be dual cells in an electroplating system or apparatus. The electroplating cells can be neutralized asynchronously. The selected electroplating cells can be neutralized while electroplating metal is performed on wafers in non-selected electroplating cells.

[0094] Referring to FIG. 6B, the selected electroplating cell 130 can be isolated by closing the drain isolation valve 162, thereby isolating the selected electroplating cell 130 from the reservoir 110. In some implementations, the selected electroplating cell 130 can be isolated or further isolated by closing the cell isolation valve 102, thereby isolating the reservoir 110 from the pump 104. In some implementations, the selected electroplating cell 130 can be isolated or further isolated by closing the diverter valve 654, thereby isolating the anode chamber 138 from the reservoir 110. The electroplating cell loop is now completely isolated from the reservoir 110.

[0095] In some implementations, chemical recovery can be performed before or after the selected one or more electroplating cells are isolated. Chemical recovery can recover as much chemical as possible from the electroplating cell loop. Gravitational chemical recovery can be performed before active chemical recovery, thereby bringing residual chemicals in the electroplating cell loop back to the reservoir.

[0096] Referring to FIG. 6B, gravity chemical recovery can be performed by opening the drain isolation valve 162 to recover residual chemicals (e.g., electrolyte) in the return line 160 and the plating cell 130 into the reservoir 110. In addition, the cell isolation valve 128 can be opened to recover residual chemicals in the feed line 120 into the reservoir 110 while the drain isolation valve 162 remains open.

[0097] In some implementations, an active chemical purge can be performed after isolating the selected one or more plating cells. The active chemical purge can be performed by providing one or more gases through the feed line, filter, fluid contactor, or other hardware components to remove residual chemicals from the plating cell circuit.

[0098] Referring to FIGS. 6B and 6C, after isolating one or more plating cells 130, an active chemical recovery can be performed. The nitrogen supply valve 680 can be opened so that nitrogen is pushed through the feed line 120 and out.

[0099] After isolating the selected one or more plating cells, a suction is performed on the selected one or more plating cells. The suction removes any residual chemicals in the body plating cell. This can be achieved by the body suction valve and body suction pump fluidly coupled to the selected one or more plating cells. The suction also removes residual chemicals in the HRVA chamber and the anode chamber. The suction of the HRVA chamber can be accomplished by the HRVA chamber suction valve and the HRVA / SAC suction pump fluidly coupled to the HRVA chamber. The suction of the anode chamber can be accomplished by the anode chamber suction valve and the HRVA / SAC suction pump fluidly coupled to the anode chamber. In a C-SAC configuration, the suction of the HRVA chamber occurs before the suction of the anode chamber.

[0100] Referring to FIG. 6B, the suction can be performed by opening the body suction valve 218. In addition, the cell isolation valve 128 and the recirculation valve 214 are opened to facilitate the suction of the selected one or more plating cells 130. This enables the suction of the recirculation circuit. While the recirculation circuit suction is initiated by opening the body suction valve 218, the suction of the HRVA chamber can be initiated by opening the HRVA chamber suction valve 220. The suction of the HRVA chamber continues even after the recirculation circuit suction is complete. In other words, the body suction valve 218 can be closed while the suction of the HRVA chamber continues. When the suction of the HRVA chamber is complete, the HRVA chamber suction valve 220 is closed and the suction of the anode chamber 138 can be initiated by opening the anode chamber suction valve 656. When the suction of the anode chamber 138 is complete, the anode chamber suction valve 656 is closed.

[0101] The selected one or more electroplating cells are filled with a neutralizing solution (e.g., deionized water). During the filling of the neutralizing solution, the neutralizing fill valve is opened to provide the neutralizing solution to the selected one or more electroplating cells. The level monitoring system can determine that the electroplating cell loop is full. Once the electroplating cell loop is full, the electroplating cell loop is pumped down. The pumping down of the electroplating cell loop can be performed using the body pump down valve and the body pump down pump fluidly coupled to the selected one or more electroplating cells. In some implementations, the pumping down of the anode compartment can be performed at some point during the filling and pumping down of the selected one or more electroplating cells in the electroplating cell loop.

[0102] Referring to FIG. 6B, the electroplating cell loop can be filled by opening the neutralizing fill valve 212. This provides the neutralizing solution (e.g., deionized water) to the feed line 120 via the pump 104, where the neutralizing solution flows to the selected one or more electroplating cells 130. When the selected one or more electroplating cells 130 are full of the neutralizing solution, the selected one or more electroplating cells 130 are pumped down. The pumping down is performed by opening the body pump down valve 218. In addition, the recirculation valve 214 and the cell isolation valve 128 can also be opened to facilitate the pumping down of the selected one or more electroplating cells 130. Once the pumping down of the selected one or more electroplating cells 130 is complete, the body pump down valve 218, the recirculation valve 214, and the cell isolation valve 128 are closed. While the electroplating cell loop is being filled and pumped down, the anode compartment 138 can be simultaneously pumped down by opening the anode compartment pump down valve 656. When the pumping down of the anode compartment 138 is complete, the anode compartment pump down valve 656 is closed. The filling and pumping down of the anode compartment 138 is synchronized with the one or more electroplating cells 130.

[0103] After the selected one or more electroplating cells in the electroplating cell loop are pumped down, and after the anode compartment is pumped down, the electroplating cell loop and the SAC loop can be filled with a neutralizing solution (e.g., deionized water). The fill rate (e.g., a faster rate) of the body electroplating cells in the electroplating cell loop can be different than the anode compartment. To fill the body electroplating cells in the electroplating cell loop, the neutralizing fill valve is opened. To fill the anode compartment in the SAC loop, a separate neutralizing fill valve for the SAC loop is opened. The shunt valve is closed and the second neutralizing fill valve is opened. When the body electroplating cells in the electroplating cell loop are full, recirculation can be initiated to recirculate the neutralizing solution in the electroplating cell loop. When the anode compartment is filled in the SAC loop, the anode compartment can be drained and fed to prevent the accumulation of solution and further neutralization.

[0104] Referring to FIG. 6B, the selected one or more electroplating cells 130 can be filled by opening the neutralization fill valve 212. This provides a neutralization solution (e.g., deionized water) to the feed line 120 via the pump 104, which flows to the selected one or more electroplating cells 130. The anode compartment 138 can be filled by closing the shunt valve 676 and opening the second neutralization fill valve 678 to provide the neutralization solution to the anode compartment 138. Once the selected one or more electroplating cells 130 in the electroplating cell loop are filled, the recirculation valve 214 can be opened to recirculate the neutralization solution in the electroplating cell loop. The anode compartment 138 can be filled at a slower rate. When the anode compartment 138 is filled, the anode compartment tower 152 reaches a certain liquid level, and the second neutralization fill valve 678 is closed. The drain valve 682 can be opened to bleed fluid on the input side of the C-SAC pump 672 to remove air bubbles that can be trapped in the SAC loop. The second neutralization fill valve 678 can be periodically opened and closed, and the drain valve 682 can be periodically opened and closed to perform the draining and feeding of the SAC loop.

[0105] In some implementations, a precursor dose is provided to the electroplating cell loop prior to filling the electroplating cell loop with the neutralization solution. In some cases, the neutralization solution can cause unwanted chemical precipitation of the electroplating solution in the electroplating cell loop. Accordingly, prior to filling, a precursor dose can be delivered to the selected one or more electroplating cells by opening the precursor dosing valve. In some implementations, the precursor is MSA.

[0106] After the pumping and filling, a pH check can be performed to determine the pH of the solution of the selected one or more electroplating cells. If the pH of the solution meets a safety threshold, the neutralization is complete, and maintenance can be performed. If the pH of the solution does not meet the safety threshold, at least another cycle of the pumping and filling process is repeated. In some implementations, the number of cycles can be between about 3 cycles and about 50 cycles, about 5 cycles and about 30 cycles, or about 10 cycles and about 20 cycles. In some implementations, the safety threshold can be a pH between about 3 and about 10, about 4 and about 9, or about 5 and about 8. In some cases, the pH can be manually measured by opening the door of the selected one or more electroplating cells and / or removing the top cover.

[0107] FIG. 9 shows a flowchart of an example method of performing electroplating cell neutralization, according to some implementations.

[0108] At block 910 of process 900, the selected one or more electroplating cells are isolated from a reservoir of the electroplating apparatus configured to hold an electroplating solution. The electroplating solution can contain acidic and hazardous chemicals. The electroplating apparatus can include the reservoir, a pump fluidly connected to the reservoir, a feed line fluidly connecting the one or more electroplating cells to the pump, a return line fluidly connecting the one or more electroplating cells to the reservoir, and a neutralization flush line fluidly connecting the one or more electroplating cells to the pump while bypassing the return line and the reservoir. Isolating the selected one or more electroplating cells can include closing a cell isolation valve between the reservoir and the pump, closing a cell isolation valve between the pump and the selected one or more electroplating cells, and closing a drain isolation valve between the selected one or more electroplating cells and the reservoir.

[0109] In some implementations, process 900 includes recovering electrolyte from the selected one or more electroplating cells into the reservoir. This can be done prior to isolating the selected one or more electroplating cells. The electrolyte can be recovered into the reservoir by a gravity recovery process. For example, the drain isolation valve and the cell isolation valve can be opened to recover residual chemicals into the reservoir. Additionally or alternatively, the electrolyte can also be recovered by an active chemical recovery process. For example, a gas such as nitrogen can be actively pushed through the feed line to recover residual chemicals in hardware components such as filters in the feed line.

[0110] At block 920 of process 900, the selected one or more electroplating cells are pumped down. Pumping down removes residual chemicals from the selected one or more electroplating cells in the electroplating cell circuit. In a SAC circuit, pumping down can also remove residual chemicals in the HRVA chamber and the anode chamber of the selected one or more electroplating cells. Pumping down the HRVA chamber and the anode chamber of the selected one or more electroplating cells can be independent of pumping down the selected one or more electroplating cells in the electroplating cell circuit. In some implementations, pumping down the selected one or more electroplating cells in the electroplating cell circuit can include opening a first pump down valve fluidly coupled to the selected one or more electroplating cells. In some implementations, pumping down the HRVA chamber and the anode chamber of the selected one or more electroplating cells can include opening a second pump down valve fluidly coupled to one or more of the HRVA chamber and the anode chamber. Each electroplating cell includes a cathode chamber, an anode chamber, a separator between the cathode chamber and the anode chamber, a separator frame to support the separator, and an ionically resistive element above the separator, where the HRVA chamber is formed by the ionically resistive element, the separator, and the separator frame. In some implementations, pumping down the HRVA chamber occurs prior to pumping down the anode chamber.

[0111] At block 930 of process 900, the selected one or more electroplating cells are filled with a neutralizing solution. In some implementations, the neutralizing solution includes water or deionized water. In some implementations, the neutralizing solution includes a base or a non-acidic chemical. In some implementations, filling the selected one or more electroplating cells can include opening a neutralizing fill valve in a neutralizing flush line that bypasses the return line and the reservoir. In some implementations, filling the selected one or more electroplating cells can include opening a neutralizing fill valve configured to flow the neutralizing solution through the selected one or more electroplating cells and then to a drain line to waste. After the selected one or more electroplating cells are pumped down, the selected one or more electroplating cells are filled. The fill rate of the selected one or more electroplating cells in the electroplating cell circuit can be faster than the fill rate of the anode compartments of the selected one or more electroplating cells in the SAC circuit. In some implementations, a second neutralizing fill valve is opened to fill the anode compartments of the selected one or more electroplating cells in the SAC circuit.

[0112] In some implementations, process 900 further includes recirculating the neutralizing solution through the selected one or more electroplating cell circuits. The recirculation can be initiated after the selected one or more electroplating cells are filled in the electroplating cell circuits. A recirculation valve in the neutralizing flush line can be opened to recirculate the neutralizing solution.

[0113] In some implementations, process 900 further includes circulating the neutralizing solution through the selected one or more electroplating cell circuits to a drain line to waste. In some cases, the drain line is fluidly coupled to the return line. In some cases, the drain line is fluidly coupled to the feed line.

[0114] In some implementations, process 900 further includes draining and feeding the neutralizing solution in the anode compartments of the selected one or more electroplating cells. The draining and feeding can be initiated after the anode compartments of the selected one or more electroplating cells are filled in the SAC circuit. A drain valve can be periodically opened and closed to drain the solution from the anode compartments, and a neutralizing fill valve or a second neutralizing fill valve can be periodically opened and closed to feed the neutralizing solution back to the anode compartments.

[0115] At block 940 of process 900, the pumping down and filling of the neutralizing solution are repeated until the pH of the solution of the selected one or more electroplating cells reaches a safe threshold. When the pH of the solution reaches the safe threshold, the neutralization is complete, and the electroplating apparatus can be serviced.

[0116] While the selected plating cell is isolated and neutralized, other plating cells can continue to be used for production. Thus, process 900 can include plating metal onto one or more wafers in one or more plating cells that are not selected for isolation and neutralization, where plating metal onto the one or more wafers is performed concurrently with pumping and filling the selected one or more plating cells with a neutralization solution. Moreover, the plating cells can also be neutralized asynchronously. In other words, the neutralization does not necessarily have to be performed concurrently across the entire plating apparatus. Rather, one or more plating cells can be neutralized while another one or more plating cells can begin neutralization.

[0117] FIG. 10 shows a flowchart of an example method of performing filter flushing in accordance with some implementations. Filter flushing can be performed with reference to the components shown in FIG. 6C.

[0118] At block 1010 of process 1000, one or more plating cells are isolated from a pump in a plating apparatus. The pump is configured to draw plating solution from a reservoir that is fluidly connected to the pump. The plating solution can contain acidic and hazardous chemicals. The plating apparatus can include the reservoir, the pump, a feed line fluidly connecting the one or more plating cells to the pump, a return line fluidly connecting the one or more plating cells to the reservoir, and a neutralization flush line fluidly connecting the one or more plating cells to the pump and bypassing the return line and the reservoir. Isolating the selected one or more plating cells from the pump can include closing a cell isolation valve and closing the pump.

[0119] At block 1020 of process 1000, a filter downstream of the pump is pumped. The filter is fluidly coupled to the one or more plating cells via the feed line and the cell isolation valve. Pumping the filter can be performed by opening a pump valve that is fluidly connected to the filter.

[0120] At block 1030 of process 1000, the filter is flushed with a neutralization solution using a neutralization fill valve that is fluidly coupled to the feed line. In some cases, the neutralization fill valve provides the neutralization solution to the feed line, and ultimately to the filter, through the pump. In some cases, the neutralization fill valve provides the neutralization solution to the fluid contactor, and ultimately to the filter, through the feed line in a reverse flow manner. In some implementations, the neutralization solution flows through the filter and is discharged to a waste section.

[0121] At block 1040 of process 1000, the operations of pumping and flushing with the neutralization solution are repeated until a pH of the solution from the filter reaches a safe threshold. When the pH of the solution reaches the safe threshold, the neutralization is complete, and the filter can be serviced for maintenance or replacement of the filter.

[0122] Multi-station apparatus The methods described herein can be performed by any suitable apparatus. Suitable apparatus includes hardware and a system controller with instructions to control process operations in accordance with the present implementations. For example, in some implementations, the hardware can include one or more processing stations in a process tool.

[0123] Figure 11 shows a multi-chamber electroplating apparatus, according to some implementations. The multi-chamber electroplating apparatus 1100 can include three separate electroplating modules 1102, 1104, and 1106. The multi-chamber electroplating apparatus 1100 can also include three separate modules 1112, 1114, and 1116 configured for various process operations. For example, in some implementations, one or more of the modules 1112, 1114, and 1116 can be a spin rinse drying (SRD) module. In other implementations, one or more of the modules 1112, 1114, and 1116 can be a post-electrofill module (PEM), each configured to perform a function, such as edge bevel removal, backside etching, and acidic cleaning of substrates after they are processed in one of the electroplating modules 1102, 1104, and 1106.

[0124] The multi-chamber electroplating apparatus 1100 includes a central electrodeposition chamber 1124. The central electrodeposition chamber 1124 is a chamber that holds a chemical solution used as an electroplating solution in the electroplating modules 1102, 1104, and 1106. The multi-chamber electroplating apparatus 1100 also includes a dosing system 1126 that can store and deliver additives for the electroplating solution. A chemical dilution module 1122 can store and mix chemicals used as etchants. A filtration and pump unit 1128 can filter and pump the electroplating solution used in the central electrodeposition chamber 1124 to the electroplating modules.

[0125] A system controller 1130 provides electronic and interface control needed to operate the electroplating apparatus 1100. The system controller 1130, which can include one or more physical or logical controllers, controls some or all of the characteristics of the electroplating apparatus 1100.

[0126] Signals for monitoring the process can be provided by analog and / or digital input connections of the system controller 1130 from various process tool sensors. Signals for controlling the process can be output through analog and digital output connections of the process tool. Non-limiting examples of process tool sensors that can be monitored include mass flow controllers, pressure sensors such as manometers, thermocouples, optical position sensors, etc. Appropriately programmed feedback and control algorithms can be used with data from these sensors to maintain process conditions.

[0127] The transfer tool 1140 can select a substrate from a substrate cassette, such as cassette 1142 or cassette 1144. The cassette 1142 or 1144 can be a front opening unified pod (FOUP). A FOUP is a housing designed for safely and reliably containing substrates in a controlled environment and allowing removal of the substrates for processing and measurement by tools equipped with appropriate load ports and robotic handling systems. The transfer tool 1140 can hold the substrates using vacuum suction devices or other suction mechanisms.

[0128] The transfer tool 1140 can interface with the wafer handling station 1132, the cassette 1142 or 1144, the transfer station 1150, or the aligner 1148. From the transfer station 1150, the transfer tool 1146 can acquire a substrate. The transfer station 1150 can be a slot or location from which the transfer tools 1140 and 1146 can transfer substrates without passing through the aligner 1148. However, in some implementations, to ensure that the substrates are properly aligned on the transfer tool 1146 for accurate transfer to the electroplating module, the transfer tool 1146 can align the substrates with the aligner 1148. The transfer tool 1146 can also deliver the substrates to one of the electroplating modules 1102, 1104, or 1106, or to one of the three separate modules 1112, 1114, and 1116 configured for various process operations.

[0129] In some implementations, a controller is part of a system, which can be part of the above-described examples. Such systems can include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems can be integrated with electronics for controlling the operation of the semiconductor processing equipment before, during, and after processing of a semiconductor wafer or substrate. The electronics can be referred to as the “controller,” which can control various components of the system or subsystems thereof. The controller, depending on the processing requirements and / or system type, can be programmed to control any of the processes disclosed herein, including delivery of fluids, selection of electroplating bath and, isolation of electroplating baths, opening / closing of valves, start sequences for fill and / or pump, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of tools and other transfer tools, and / or load locks connected or interfaced with a particular system.

[0130] Broadly speaking, the controller can be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits can include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions can be instructions (or sets of instructions) that are executed by the controller to implement methods and processes described herein, such as the methods and processes of the example methods for controlling a copper electroplating process. The program instructions can be encoded in various operating systems (OS) such as DOS, Windows, Linux, Unix, and the like, or embedded systems that do not have an OS.

[0131] In some implementations, the controller can be part of, or coupled to, a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller can be in "the cloud" or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer can enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication or processing operations, change parameters of current processing, set processing steps to follow in sequence from the current processing, or to start a new process. In some examples, a remote computer (e.g., a server) can provide process recipes to the system over a network, which can include a local network or the Internet. The remote computer can include a user interface that enables entry or programming of parameters and / or settings, which are then transmitted over the network from the remote computer to the system. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters can be specific to a type of process to be performed, and a type of tool that the controller is configured to interface with or control. Thus as described above, the controller can be distributed, such as by including one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such a purpose would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located off the chamber, such as in a mainframe computer or as part of a remote computer that work in combination to control a process on the chamber.

[0132] Conclusion It is to be understood that the examples and implementations described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the purview of this disclosure. While various design alternatives can be implemented, various details can be omitted in order not to obscure the principles of the embodiments. Accordingly, it is to be understood that the examples are to be considered merely illustrative of the principles and applications of the present disclosure. Accordingly, modifications and / or changes can be suggested by those skilled in the art, and are to be included within the purview and range of equivalents of the claims.

Claims

1. An electroplating apparatus, comprising: Storage tanks, configured to contain electroplating solutions; Pump; One or more electroplating tanks, each of the one or more electroplating tanks comprising: Cathode chamber; Anode chamber, which is configured to house the anode; and A diaphragm located between the cathode chamber and the anode chamber; A feed line that is fluidly coupled to the outlet of the pump and the one or more electroplating tanks; A return line, fluidly coupled to the one or more electroplating tanks and also fluidly coupled to one or more of the following: (1) a tank return line, wherein the tank return line is fluidly coupled to the tank; (2) a bypass return line, wherein the bypass return line bypasses the tank and is fluidly coupled to the pump; and (3) a discharge line, wherein the discharge line leads to the waste section; and A neutralization filling line, which is fluidly coupled to the one or more electroplating tanks and configured to provide a neutralization solution to the one or more electroplating tanks.

2. The electroplating apparatus according to claim 1, wherein the neutralizing solution comprises deionized water.

3. The electroplating apparatus according to claim 1, wherein the inlet of the pump is fluidly coupled to the bypass return line and the tank output line.

4. The electroplating apparatus of claim 1, wherein the return line is fluidly coupled to the discharge line, wherein the neutralization filling line is configured to circulate the neutralization solution through the one or more electroplating tanks and to the discharge line via the return line.

5. The electroplating apparatus of claim 1, wherein the return line is fluidly coupled to the bypass return line, wherein the neutralization filling line is configured to circulate the neutralization solution through the one or more electroplating tanks and the bypass return line via the pump and the feed line.

6. The electroplating apparatus according to claim 1, wherein the return line is fluidly coupled to the storage tank, and wherein the neutralization filling line circulates the neutralization solution to the bypass return line or the discharge line, bypassing the storage tank.

7. The electroplating apparatus according to claim 1, further comprising: A discharge line, wherein the discharge line is fluidly coupled to the return line or the feed line.

8. The electroplating apparatus according to claim 1, further comprising: A suction line that is fluidly coupled to the one or more electroplating tanks, wherein the suction line includes a main suction valve configured to suction the one or more electroplating tanks.

9. The electroplating apparatus of claim 8, wherein each of the one or more electroplating tanks further comprises an ion resistive element located above the diaphragm.

10. The electroplating apparatus of claim 9, wherein each of the one or more electroplating tanks further comprises a diaphragm frame configured to support the diaphragm.

11. The electroplating apparatus according to claim 10, further comprising: An HRVA chamber suction line is fluidly coupled to a region below the ion resistive element in one or more electroplating tanks, wherein the HRVA chamber suction line includes an HRVA chamber suction valve configured to suction the region below the ion resistive element.

12. The electroplating apparatus according to claim 11, further comprising: The system controller is configured with instructions to perform the following operations: (a) Open the discharge isolation valve between the return line and the storage tank to allow the electrolyte in the one or more electroplating tanks to return to the storage tank; (b) Close the discharge isolation valve to isolate the selected one or more electroplating tanks from the storage tank; (c) Open one or both of the main suction valve and the HRVA chamber suction valve to suction the selected one or more electroplating tanks; as well as (d) Open the neutralization filling valve connected to the neutralization filling line to fill the neutralization solution into the selected one or more electroplating tanks.

13. The electroplating apparatus according to claim 12, wherein the system controller is further configured with instructions to perform the following operations: Repeat steps (c) and (d) until the pH of the solution from the selected one or more electroplating tanks reaches a safe critical value.

14. The electroplating apparatus of claim 12, wherein the system controller is further configured with instructions to perform the following operations: After step (c) is completed and before step (d), after suctioning the selected one or more electroplating tanks, close the main suction valve and the HRVA chamber suction valve; and After step (d) is completed, the neutralization filling valve is closed.

15. The electroplating apparatus of claim 12, wherein the system controller is further configured with instructions to perform the following operations: After step (d), the recirculation valve connected to the return line and the bypass return line is opened to allow the neutralized solution to be recirculated through the selected one or more electroplating tanks.

16. The electroplating apparatus according to claim 12, further comprising: A second neutralization filling line is fluidly coupled to the one or more electroplating tanks, wherein the second neutralization filling line includes a second neutralization filling valve configured to supply a second neutralization solution to a tower fluidly coupled to the one or more electroplating tanks; as well as An anode chamber suction line, fluidly coupled to the tower, wherein the anode chamber suction line includes an anode chamber suction valve configured to suction the tower, and wherein the system controller is further configured with instructions to perform the following operations: Following step (d), the second neutralization filling valve is opened to fill the tower with the second neutralization solution; and After filling the tower with the second neutralization solution, close the second neutralization filling valve.

17. The electroplating apparatus of claim 12, wherein the neutralization filling line further comprises a precursor dispensing valve for dispensing a precursor to the one or more electroplating tanks, wherein the system controller is further configured to have instructions to perform the following operations: Prior to step (d), the precursor dispensing valve is opened to dispense the precursor into one or more of the selected electroplating tanks.

18. The electroplating apparatus of claim 17, wherein the precursor comprises methanesulfonic acid (MSA), and precipitation is prevented when the neutralizing solution is mixed with the electroplating solution.

19. The electroplating apparatus according to claim 1, further comprising: The system controller is configured with instructions to perform the following operations: (a) Select at least one of the one or more electroplating tanks for isolation and neutralize it with the neutralizing solution; (b) Suctioning is performed on at least one of the selected one or more electroplating tanks; (c) Neutralize at least one of the selected one or more electroplating tanks with the neutralizing solution; as well as (d) Electroplating metal onto one or more wafers in one or more electroplating tanks that were not selected for isolation and neutralization, wherein the metal is electroplated onto the one or more wafers while performing steps (b)-(c).

20. The electroplating apparatus of claim 1, wherein the feed line includes a filter downstream of the pump, wherein the neutralization filling line is configured to supply the neutralization solution to the pump and to allow the neutralization solution to flow through the feed line and the filter.

21. The electroplating apparatus according to claim 20, further comprising: The system controller is configured with instructions to perform the following operations: (a) Close the tank isolation valve connected to the feed line to isolate the pump from the one or more electroplating tanks; as well as (b) Open the neutralization filling valve connected to the neutralization filling line to flush the filter with the neutralization solution.

22. A method for neutralizing one or more electroplating tanks in an electroplating apparatus, the method comprising: Isolate one or more selected electroplating tanks from the storage tanks in the electroplating apparatus that are configured to contain the electroplating solution; Suction is drawn from one or more of the selected electroplating tanks; Fill the selected one or more electroplating tanks with the neutralizing solution; as well as Repeat the aspiration and filling with the neutralizing solution until the pH of the solution from the one or more electroplating tanks reaches a safe critical value.

23. The method of claim 22, wherein the neutralizing solution comprises deionized water.

24. The method of claim 22, wherein the neutralizing solution comprises a base.

25. The method of claim 22, wherein suction of the selected one or more electroplating tanks comprises: Open a first suction valve that is fluidly coupled to one or more of the selected electroplating tanks, each of which includes a cathode chamber, an anode chamber, and an ion resistive element located between the cathode chamber and the anode chamber; as well as Open the second suction valve, which is fluidly coupled to the area below the ion resistive element in the selected one or more electroplating tanks.

26. The method of claim 22, further comprising: After the neutralizing solution is filled into one or more selected electroplating tanks, the neutralizing solution is recycled through the one or more selected electroplating tanks.

27. The method of claim 22, further comprising: Before isolating the selected one or more electroplating tanks, the electrolyte in the one or more electroplating tanks is recovered into the storage tank.

28. The method of claim 22, further comprising: Metal is electroplated onto one or more wafers in one or more electroplating tanks that are not selected for isolation and neutralization, wherein the metal is electroplated onto the one or more wafers while the selected one or more electroplating tanks are being aspirated and filled with the neutralization solution.

29. A method for rinsing a filter, the method comprising: The pump is isolated from one or more electroplating tanks in the electroplating apparatus, wherein the pump is configured to draw electroplating solution from a storage tank; The filter located downstream of the pump is drawn in, wherein the filter is fluidly coupled to the one or more electroplating tanks; The filter is flushed with a neutralization solution using a neutralization filler valve that is fluidly coupled to the feed line; as well as Repeat the aspiration and rinsing with the neutralizing solution until the pH of the solution from the filter reaches a safe critical value.

30. The method of claim 29, wherein the neutralizing solution comprises deionized water.

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