Electroplating cell with copper acid correction module for substrate interconnect formation

Abstract

The present invention generally provides an apparatus and method for neutralizing an acid in a plating solution. The apparatus generally includes a plating cell having an anolyte compartment containing an anolyte and a catolyte compartment containing a catolyte, wherein the anolyte compartment has an anolyte inlet and an anolyte drain and the catolyte compartment has a catolyte inlet and a catolyte drain, and a cell membrane disposed in the cell between the anolyte compartment and the catolyte compartment, wherein the membrane is selective to hydrogen ions and copper ions. The apparatus further includes a catolyte storage unit in fluid communication with the catolyte inlet and an electrochemical device in fluid communication with the catolyte chamber, the electrochemical device being configured to receive a portion of aged catolyte solution and correct a catolyte concentration. The method generally includes supplying an electrolyte solution to a copper plating cell, plating copper onto a substrate in the plating cell with the electrolyte solution, removing aged electrolyte solution from the plating cell, and neutralizing a portion of the used electrolyte solution with an electrochemical device.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to correcting the concentration of semiconductor electrolyte solutions.

[0003] 2. Description of the Related Art

[0004] Metallization for sub-quarter micron sized features is a foundational technology for present and future generations of integrated circuit manufacturing processes. In devices such as ultra large scale integration-type devices, i.e., devices having integrated circuits with more than a million logic gates, the multilevel interconnects that lie at the heart of these devices are generally formed by filling high aspect ratio interconnect features with a conductive material, such as copper or aluminum. Conventionally, deposition techniques such as chemical vapor deposition (CVD) and physical vapor deposition (PVD) have been used to fill these interconnect features. However, as interconnect sizes decrease and aspect ratios increase, void-free interconnect feature fill via conventional metallization techniques becomes increasingly difficult. As a result thereof, plating techniques, such as electrochemical plating (ECP) and electroless plating, for example, have emerged as viable processes for filling sub-quarter micron sized high aspect ratio interconnect features in integrated circuit manufacturing processes.

[0005] In an ECP process sub-quarter micron sized high aspect ratio features formed on a substrate surface may be efficiently filled with a conductive material, such as copper, for example. ECP plating processes are generally two stage processes, wherein a seed layer is first formed over the surface features of the substrate, and then the surface features of the substrate are exposed to an electrolyte solution while an electrical bias is simultaneously applied between the substrate and an anode positioned within the electrolyte solution. The electrolyte solution is generally rich in ions to be plated onto the surface of the substrate. Therefore, the application of the electrical bias causes these ions to be urged out of the electrolyte solution and to be plated as a metal on the seed layer. The plated metal, which may be copper, for example, grows in thickness and forms a copper layer that fills the features formed on the substrate surface.

[0006] In order to facilitate and control this plating process, several additives may be utilized in the electrolyte plating solution. For example, a typical electrolyte solution used for copper electroplating may consist of copper sulfate solution, which provides the copper to be plated, having sulfuric acid and copper chloride added thereto. The sulfuric acid may generally operate to modify the acidity and conductivity of the solution. The electrolytic solutions also generally contain various organic molecules, which may be accelerators, suppressors, levelers, brighteners, etc. These organic molecules are generally added to the plating solution in order to facilitate void-free super-fill of high aspect ratio features and planarized copper deposition. Accelerators, for example, may be sulfide-based molecules that locally accelerate electrical current at a given voltage where they absorb. Suppressors may be polymers of polyethylene glycol, mixtures of ethylene oxides and propylene oxides, or block copolymers of ethylene oxides and propylene oxides, for example, which tend to reduce electrical current at the sites where they absorb (the upper edges/corners of high aspect ratio features), and therefore, slow the plating process at those locations, which reduces premature closure of the feature before the feature is completely filled. Levelers, for example, may be nitrogen containing long chain polymers, which operate to facilitate planar plating. Additionally, the plating bath usually contains a small amount of chloride, generally between about 20 and about 60 ppm, which provides for adsorption of suppressor molecules on the cathode, while also facilitating proper anode corrosion.

[0007] Although the various organic additives facilitate the plating process and offer a control element over the interconnect formation processes, they also present a challenge, as the additives are known to eventually break down and become contaminate material in the electrolyte solution. Conventional plating apparatuses have traditionally dealt with these organic contaminants via bleed and feed methods (periodically replacing a portion of the electrolyte), extraction methods (filtering the electrolyte with a charcoal filter), photochemical decomposition methods (using UV in conjunction with ion exchange and acid-resistant filters), and/or ozone treatments (dispensing ozone into the electrolyte). However, these conventional methods are inefficient, expensive to implement and operate, or bulky, and may generate hazardous materials or other kinds of contaminants as byproducts.

[0008] Furthermore, conventional systems may utilize a soluble metal anode to provide a continuous supply to metal ions for electrolyte replenishment. However, anode dissolution has disadvantages such as undesirable side products, e.g., sludge and copper ball formation, and undesirable side effects, e.g., anode passiviation, non-uniform anode dissolution, and consumption/breakdown of organic additives. Therefore, there is a need for a method and apparatus that minimize the formation and effects of contaminants in semiconductor electroplating baths, wherein the method and apparatus addresses the deficiencies of conventional devices.

SUMMARY OF THE INVENTION

[0009] Embodiments of the invention generally provide an electrochemical plating system having an anolyte compartment and a catolyte compartment, wherein the anolyte compartment has an anolyte inlet and an anolyte drain, and a membrane disposed between the anolyte compartment and the catolyte compartment, wherein the membrane is selective to positively charged ions, e.g., hydrogen ions and copper ions. Embodiments of the invention further provide a catolyte storage unit in fluid communication with the catolyte inlet and an electrochemical device in fluid communication with the catolyte compartment, the electrochemical device being configured to correct an catolyte concentration.

[0010] Embodiments of the invention further provide a method for plating copper. The method generally includes supplying an electrolyte solution to a copper plating cell, plating copper onto a substrate in the plating cell with the electrolyte solution, removing aged electrolyte solution from the plating cell, and correcting a catolyte concentration in the aged electrolyte solution with an electrochemical device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] So that the manner in which the above recited features of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof, which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

[0012] FIG. 1 illustrates an exemplary plating system incorporating an electrochemical membrane device (ELDC) cell of the invention.

[0013] FIG. 2 illustrates a schematic view of an exemplary ELDC cell of the invention.

[0014] FIG. 3 illustrates a schematic view of another exemplary ELDC cell of the invention.

[0015] FIG. 4 illustrates a schematic view of another exemplary ELDC cell of the invention.

[0016] FIG. 5 Illustrates a schematic view of another exemplary ELDC cell of the invention.

[0017] FIG. 6 Illustrates a schematic view of another exemplary ELDC cell of the invention.

[0018] FIG. 7 illustrates an exemplary plating system incorporating an ELDC cell and an electrodialysis cell (EDC).

[0019] FIG. 8 illustrates an exemplary embodiment of a plating system incorporating an EDLC system wherein the concentration of acid is decreased while the concentration of copper is simultaneously increased.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] FIG. 1 illustrates an exemplary plating system 100 of the present intention. Plating system 100 generally includes a plating cell 101, which may be an electrochemical plating (ECP) cell for copper superfill plating or another electroplating cell configuration known in the semiconductor art. The plating cell 101 generally includes an anolyte inlet 105 configured to deliver an anolyte, e.g., a plating processing fluid, to the plating cell 101, and an anolyte outlet or drain 106 configured to retrieve anolyte from plating cell 101. The anolyte is delivered to the plating cell 101 via inlet 105, which is in fluid communication with an anolyte storage unit 102. A fluid pump 104 is generally positioned between the anolyte storage unit 102 and the plating cell 101 and is configured to deliver the anolyte to plating cell 101 upon actuation thereof. The anolyte generally is contained in the storage unit 102 and an anolyte compartment 108 with an anode 122 disposed therein. The anode 122 may generally be soluble, e.g., a copper anode, or insoluble, e.g., platinum. The anolyte compartment 108 is generally separated from a catolyte compartment 110 having a cathode, e.g., substrate, disposed therein, by a cation exchange membrane 112.

[0021] An insoluble anode eliminates the formation of undesirable side products and effects generally associated with soluble anodes. However, soluble copper anodes do not require electrochemical devices, which are designed to neutralize the excess of acid generally forming on the insoluble anode. Instead, deionized water is generally added to storage unit 102 to compensate for the loss of water transported from the anolyte into the catolyte along with copper ions.

[0022] The anolyte generally includes copper sulfate and a minimal amount of sulfuric acid, e.g., an amount sufficient to provide an anolyte pH of from about 2 to about 6. When the pH of the anolyte is less then 2, the hydrogen ion concentration migrating to the catolyte compartment is small, i.e., less than about 10 to about 100 times the concentration of copper ions migrating to the catolyte compartment. The catolyte, e.g., a copper superfill electrolyte, generally includes copper sulfate, sulfuric acid, copper chloride, and additives to aid in plating, such as accelerators, suppressors, and levelers. The cation exchange membrane 112 generally is selective to positively charged ions, e.g., hydrogen ions (H+) and copper ions (Cu2+); therefore the H+ and Cu2+ migrate from the anolyte compartment to the catolyte compartment. The H+ concentration migrating to the catolyte compartment is very small, i.e., less than 1000 times the concentration of Cu2+ migrating to the catolyte compartment. The Cu2+ migration is generally necessary to compensate for copper losses in the catolyte solution due to copper plating. As a result of copper migration, the anolyte copper concentration decreases and becomes more acidic over time. Embodiments utilizing a soluble anode generally have a constant anolyte acidity over time. Additionally, the H+ penetrating the membrane slowly effects the catolyte concentration. Therefore, electrochemical membrane devices (ELDC) are included in embodiments of the invention to correct the anolyte and catolyte concentrations (which may collectively be referred to as electrolyte in the embodiments below).

[0023] The anolyte outlet 106 may be in fluid communication with an input of the ELDC 103, which may have an output thereof, that is in fluid communication with the anolyte storage unit 102. The cell 101 further includes a catolyte outlet 114 configured to retrieve catolyte from the catolyte compartment 110. The catolyte is recirculated to the catolyte compartment 110 through a catolyte inlet 116, which is in fluid communication with a catolyte storage unit 118. The catolyte passing from the catolyte outlet 114 to the catolyte storage unit 118 may pass through a second ELDC 120 configured to correct the catolyte concentration.

[0024] Generally, the EDLC chambers 103 and 120, hereinafter referred to only in terms of ELDC 120, are configured to receive a portion of the used electrolyte returning from plating cell 101 to anolyte storage unit 102. Generally the same ELDC chamber may be used for chamber 103 and 120, with the exception that the catolyte purity requirement may be higher than that for the anolyte, as the catolyte should have all solids and contaminants removed before reentry to the catolyte chamber, e.g., the copper electrode anode utilized in one or more embodiments discussed below generally is not in direct contact with catolyte to be corrected. Further, ELDC cells utilized in the anolyte loop generally do not include bipolar exchange membranes because copper hydroxide forms on the membrane causing the membrane to fail.

[0025] The received portion of aged electrolyte is neutralized within the ELDC 120 resulting in a restored electrolyte, which may then be reintroduced into the anolyte storage unit 102 for subsequent use in plating operations. The restored portion of the electrolyte may generally include one or more concentrated salts and acids that were originally present in the electrolyte and that are generally free of contaminants resulting from organic additive breakdown in the electrolyte. Although the exemplary ELDC illustrated in FIG. 1 receives the entire aged electrolyte passing through outlet 106, it is contemplated that various configurations of ELDCs may be implemented, which may receive only a portion of the used electrolyte.

[0026] FIG. 2 illustrates a schematic view of an exemplary ELDC 120 of the present invention. The exemplary ELDC 120, for example, may be implemented into an ECP system configured to plate copper onto semiconductor substrates. The exemplary ELDC 120 generally includes an outer housing 201 configured to hold or confine the essential elements of ELDC 120. A first end of housing 201 generally includes a copper anode source 203, while a second end of housing 201 generally includes a cathode source 202. Anode source 203 and cathode source 202 are generally positioned on opposite/opposing ends of housing 201. The volume between cathode source 202 and anode source 203 within housing 201 generally includes a plurality of ELDC chambers, wherein the ELDC chambers generally include an anode chamber 204 and a cathode chamber 205 corresponding to the anode or cathode positioned in the respective end of housing 201. A selectively permeable membrane 210 individually separates the respective chambers 204, 205.

[0027] These membranes may be one of many commercially available membranes. For example, Tokuyama Corporation manufactures and supplies various hydrocarbon membranes for electrodialysis and related applications under the trade name “Neosepta.” Perfluorinated cation membranes, which are stable to oxidation and useful when it is necessary to separate an insoluble anode compartment by a cation membrane, are generally available from DuPont Co as Nafion membranes N-117, N-450, or from Asahi Glass Company (Japan) under the trade name Flemion as Fx-50, F738, and F893 model membranes. Asahi Glass Company also produces a wide range of polystyrene based ion-exchange membranes under the trade name Selemion, which can be very effective for concentration/desalination of electrolytes and organic removal (cation membranes CMV, CMD, and CMT and anion membranes AMV, AMT, and AMD). There are also companies that manufacture similar ion-exchange membranes (Solvay (France), Sybron Chemical Inc. (USA), Ionics (USA), and FuMA-Tech (Germany) etc.). Further, in order to minimize the penetration of copper ions into cathode compartment, it may be helpful to separate this compartment by a bipolar ionexchange membrane that is made from cation and anion membranes compiled together. Bipolar membranes, such as models AQ-BA-06 and AQ-BA-04, for example, are commercially available from Aqualitics (USA) and Asahi Glass Co.

[0028] In a first embodiment of the invention, as illustrated in FIG. 2, a membrane 210, which is selective and penetrable preferably to univalent cations, especially to H+, separates the respective chambers 204, 205. Cathode chamber 205 may be supplied with a sulfuric acid solution via conduit 214, which may operate to circulate the acid solution through the respective chamber.

[0029] In operation, used electrolyte from a plating system is delivered to anode chamber 204 via conduit 208, which may be in communication with an electrolyte drain of an ECP cell. An electrical bias is applied across ELDC cell 120 via anode 203 and cathode 202. Generally the voltage drop between the cathode and anode is from about 0.4 volts to about 1.5 volts. The use of a soluble anode in the ELDC cell removes the need for a soluble anode in the ECP cell, as the ELDC cell serves to replenish the copper in the anolyte, remove acid, and facilitate anode maintenance. As a result, anode by-products will not permeate the cation exchange membrane to effect plating in the catolyte chamber.

[0030] The application of the electrical bias across ELDC cell 120 operates to urge ions in the aged electrolyte solution towards the respective poles, i.e., positive ions will be urged in the direction of the cathode, while negative ions will be urged in the direction of the anode. Therefore, the disassociated copper ions from the soluble copper anode 203, which are generally illustrated as Cu2+ in FIG. 2, are urged in the direction of cathode 202 into the aged electrolyte solution. Similarly, disassociated hydroxide ions, which are generally illustrated as OH−, are urged in the direction of anode 203. The copper ions supplement the reduced concentration of copper in the electrolyte and the hydroxide ions neutralize the excess acid present in the electrolyte. In addition, the bipolar membrane allows for removal of H+ ions from the aged electrolyte to further neutralize the excess acid. The formed acidic copper sulfate solution may then be removed from anode chamber 204 and re-circulated into the plating system (or an electrolyte solution tank, etc.), as CuSO4/H2SO4 are primary elements of an electrolyte solution for a copper electroplating system. Therefore, ELDC 120 generally operates to receive aged electrolyte from a plating system and separate viable components (copper sulfate and sulfuric acid) from the aged electrolyte for reuse in the plating system.

[0031] FIG. 3 illustrates another embodiment of the invention. In this embodiment, aged electrolyte is supplied to ELDC cell 120 via conduit 208. Conduit 208 supplies the aged electrolyte into an input cell or chamber 300 in the ELDC cell 120. While the aged electrolyte is being supplied to the input chamber 300, an electrical bias is applied across ELDC cell 120 via cathode 202 and anode 203. ELDC 120 further includes 2 selectively permeable membranes 302 and 304, which are generally cation exchange membranes to allow ionic transfer from the anode 203 to the cathode 202. Anode chamber 204A is supplied with copper sulfate solution and cathode chamber 205A may be supplied with a sulfuric acid solution via conduit 214.

[0032] In operation, the disassociated copper ions in the aged electrolyte solution are urged in the direction of cathode 202 into the aged electrolyte solution of input chamber 300. Similarly, positive hydrogen ions (H+) are urged in the direction of the cathode 202 into the cathode chamber 205A. Furthermore, although Cu2+ also penetrates the membrane 304, the amount is negligible because the rate of H+ migrating to the cathode chamber 205A is about 100 times greater than the copper ion migration. To eliminate copper migration into the cathode chamber 205A, a membrane selective to H+, for example, the Neosepta CMS membrane, may be used to separate the cathode chamber and the input chamber. To even further eliminate the copper migration, membrane 304 may be a bipolar membrane. The use of the bipolar membrane further provides hydroxide migration from the cathode chamber 205A to the input chamber 300 to further neutralize the acid. More particularly, the positive copper and hydrogen ions in input chamber 300 are urged towards cathode 202, and are allowed to pass into the neighboring chambers, as the membranes separating chambers 204A, 300, and 205A are cationic membranes, which may generally be configured to transmit the respective positive ions therethrough in the direction of the cathode 202.

[0033] FIG. 4 illustrates an alternative embodiment of the invention. This embodiment varies from that illustrated in FIG. 3 in that only excess acid is extracted from the aged electrolyte. Therefore, anode 203 is insoluble and anode chamber 204A is supplied with a sulfuric acid solution via conduit 406. The sulfuric acid is removed from anode chamber via conduit 406. Membrane 302 is generally an anionic membrane that allows negatively charged sulfate ions (SO4−) to migrate from the aged electrolyte to the anode chamber 204A in the direction of the anode 203.

[0034] Similar to the alternative embodiment illustrated in FIG. 3, membrane 304 is a bipolar membrane, whereby H+ migrates from input chamber 300 to cathode chamber 205A and OH− migrates from cathode chamber 205A to input chamber 300. Since no additional copper is added to the aged electrolyte to correct the concentration, concentrated copper sulfate solution is generally added to the ELCD output 402. A sensor 404 provides acid control of the copper and hydrogen concentration in the output 402. The sensor 404 provides acid concentration control by interrupting the current flowing when the conductivity of the output 402 falls below a predetermined level. The predetermined level may vary depending on system requirements. Alternatively, the concentration of acid in the output 402 may be regulated by a controller (not shown). The controller may regulate the ELCD 120 current passing between cathode and anode depending on current flowing through the copper solution in the plating cell 101. An additional controller (not shown) may generally control the concentration of copper sulfate in the output 402, thereby determining the amount of concentrated copper sulfate solution to be added to the output 402.

[0035] FIG. 5 illustrates another embodiment of an exemplary ELDC 500 of the invention that generally corrects both acid and copper ion concentration in the aged electrolyte. ELDC 500 is similarly constructed to ELDC 120, in that ELDC 500 includes an anode chamber 502 and a cathode chamber 504. In similar fashion to ELDC 120, an inlet 512 is used to communicate used or aged electrolyte from a plating cell, such as a copper ECP cell, into the input chambers 506 of ELDC 500. Immediately outward of the input chambers 506 are individual copper feed chambers 508. Copper feed chambers 508 generally include a fluid inlet and a fluid outlet configured to receive and expel a circulating fluid, which may be a copper sulfate solution. In this configuration, a diluted, e.g., from about 0.01 M to about 0.1 M, sulfuric acid solution may be circulated between an isolation chamber 510 positioned in the anodic direction of the feed chamber 508 and the anode chamber 502 and a cathode chamber 504.

[0036] The membrane structure of ELDC 500 is similar to the membrane structure of ELDC 120. However, ELDC 500 includes a slight variation on the membrane configuration in order to accommodate the additional chambers. More particularly, the membrane structure generally follows an alternating sequence, i.e., from left to right, an anionic membrane, then a cationic membrane, then a bipolar membrane, then anionic membrane, etc.

[0037] In operation, ELDC 500 operates similarly to ELDC 120 illustrated in FIG. 2, as the aged electrolyte is supplied to input chambers 506 via conduit 512, while electrical bias is applied between cathode 516 and anode 518. However, rather than a soluble copper anode electrode, an insoluble anode electrode is used to minimize the anode maintenance and the copper sulfate solution is corrected by copper ion addition. The copper ions may be fed to the aged electrolyte from a fresh copper sulfate solution, or by dry copper sulfate salt via conduit 524. The depleted copper sulfate solution may then be retrieved from the feed chambers 508 via conduit 520 for replenishment. The application of the electrical bias causes positively charged ions in the aged electrolyte solution to migrate towards the cathode 516, while negatively charged ions are urged to migrate towards the anode 518. The configuration of cationic, anionic, and bipolar membranes operates to transport positive copper ions, positive hydrogen ions, negative hydroxide ions, and negatively charged sulfate ions between the respective membranes and into the desired chambers as illustrated in FIG. 5. The positive copper ions and the negative hydroxide ions combine to form renewed concentrated copper sulfate, which may then be extracted from ELDC 500 for reuse in a copper plating system. The anode 502, cathode 504, and isolation chambers 510 have a dilute sulfuric acid solution circulating between the chambers. The acid retrieved from chambers 502, 504, and 510 via conduit 514 accumulates in tank 522. Periodically, water may be added to the tank 522 so that the acid remains diluted and the excess volume of acid is discarded where it may be neutralized or disposed of. The diluted acid is then recirculated to chambers 502, 504, and 510 via conduit 526.

[0038] FIG. 6 illustrates another embodiment of an exemplary ELDC 600 of the invention. ELDC 600 is similar in structure to ELDC 500 and ELDC 120 discussed above. As illustrated in FIG. 6, ELDC 600 generally includes a chamber housing having a cathode 604 positioned on a first end and anode 605 positioned on a second end. A plurality of chambers are positioned between the respective cathode 604 and anode 605. However, ELDC 600 includes a different configuration of membranes. More particularly, ELDC 600 generally alternates between anionic and bipolar membranes, with the anionic membranes bounding the cathode 604 and anode chambers 602.

[0039] The plurality of chambers include input chambers 601 configured to receive aged electrolyte therein via conduit 606. Anode and cathode chambers 602 and 604 and purification chamber 603 are fed by diluted sulfuric acid 612. As in the embodiment of FIG. 5, the output 608 of chambers 604 and 603 accumulate in tank 522, wherein water may be added to the output 608 to retain diluted sulfuric acid solution. In operation, ELDC 600 receives aged electrolyte 606, which generally includes positive copper and hydrogen ions, negative sulfate ions, and variously charged contaminated ions in input chambers. The aged electrolyte 606 flows through the input chambers 601, as indicated by the arrows illustrated in FIG. 6. As the aged electrolyte 606 flows through the input chambers 601, the respective positive and negative ions are drawn toward the cathode 604 and anode 605 according to their polarity, as described in previous embodiments. Therefore, as a result of the electrical potential applied across ELDC 600 by the cathode 604 and anode 605, the output 610 input chambers 601 generally consists of primarily concentrated copper sulfate and sulfuric acid (with a concentration determined by individual system requirements). Like previous embodiments, the output 610 of ELDC 600 is corrected by the addition of copper sulfate solution. The present embodiment has an advantage over conventional devices and previous mentioned embodiments. The ELCD 600 is more compact and the surface area of the electrodes is small, resulting in a lower cost for the same performance.

[0040] The embodiments illustrated in FIGS. 3 and 5 are generally used for the correction of copper electrolytes with a high concentration of copper sulfate, e.g., from about 30 g/L to about 65 g/L of copper ions. In contrast, the embodiments illustrated in FIGS. 4 and 6 are generally used to correct the concentration of electrolytes with a relatively low concentration of copper sulfate. However, an alternative embodiment of the invention contemplates the combination of the ELDC of FIG. 6 to correct (increase) low concentration of copper sulfate with an electrodialysis cell (EDC) in order to correct electrolytes with a high concentration of copper sulfate, as illustrated in FIG. 7. Additionally, combinations of the EDLC cells may be combined to produce desired concentration correction.

[0041] Plating system 100A generally includes the components of system 100, with the exception that EDC 700 is generally configured to receive a portion of the electrolyte being returned from ELDC 600 to catolyte storage unit 118. The received portion of electrolyte is separated within EDC 700 into a usable fluid portion and a discardable fluid portion, wherein the usable fluid portion may then be reintroduced into the catolyte storage unit 118 for subsequent use in plating operations. The usable portion of the electrolyte may generally include one or more concentrated salts and acids that were originally present in the plating solution and that are generally free of contaminants resulting from organic additive breakdown in the plating solution. The discardable portion of the plating solution, which generally represents one or more dilute acids in conjunction with plating solution additives, contaminants and traces of copper, is separately output from EDC 700 and captured for disposal or neutralization thereof without returning to the catolyte storage unit 118. The usable and discardable portions of the plating solution are generally separated by alternating anionic and cationic membranes. Copper sulfate solution generally flows between anionic and cationic membranes and sulfuric acid generally flows between anionic membranes and the anode and cathode.

[0042] FIG. 8 illustrates an exemplary embodiment of a plating system 100B incorporating an EDLC system wherein the concentration of acid is decreased while the concentration of copper is simultaneously increased utilizing the EDLC chamber 500 detailed in FIG. 5. Plating system 100B generally includes the components of system 100, with the exception that ELDC 103 is generally replaced by a filter 802 and column 801. Generally copper oxide or copper hydroxide is utilized to correct the copper concentration. Copper oxides dissolve only in acidic solutions as a result of reaction with the acid. After contact with the aged electrolyte, the acid formed on the insoluble anode disappears and the copper concentration returns to its original concentration. The copper oxides, generally in powder or granule form, are placed in column 801 and the aged anolyte exiting the anode chamber 108 passes through column 801 and filter 802. The filter 802 protects the anolyte loop from undesirable copper oxide particles. This embodiment may generally be utilized when the concentration of copper in the anolyte need not be precisely controlled.

[0043] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A copper plating system, comprising:

an anolyte compartment, wherein the anolyte compartment has an anolyte inlet;

an anolyte storage unit in fluid communication with the anolyte inlet;

a catolyte compartment;

a catolyte storage unit in fluid communication with the catolyte inlet;

a membrane disposed between the anolyte compartment and the catolyte compartment, wherein the membrane is selective to hydrogen ions and copper ions; and

a catolyte electrochemical device in fluid communication with the catolyte compartment, the catolyte electrochemical device being configured to correct a catolyte concentration.

2. The copper plating system of claim 1, further comprising an anolyte electrochemical device in fluid communication with the anolyte compartment, the anolyte electrochemical device being configured to correct an anolyte concentration.

3. The copper plating system of claim 1, wherein the catolyte compartment comprises copper sulfate, sulfuric acid, copper chloride, and organic additives.

4. The copper plating system of claim 1, wherein the anolyte compartment comprises copper sulfate and sulfuric acid in an amount sufficient to provide a pH of from about 2 to about 6.

5. The copper plating system of claim 1, wherein the catolyte electrochemical device comprises:

a housing having a cathode electrode and an anode electrode;

an anode chamber positioned proximate the anode electrode and between the cathode electrode and the anode electrode, wherein the anode chamber is configured to receive aged catolyte solution;

a cathode chamber positioned proximate the cathode electrode and between the cathode electrode and the anode chamber, wherein the anode chamber is configured to neutralize acid in the aged catolyte solution; and

a bipolar membrane positioned between the anode chamber and the cathode chamber configured to remove hydrogen ions from the aged catolyte solution and provide hydroxide ions to the aged catolyte solution.

6. The copper plating system of claim 5, wherein the anode electrode is insoluble and is configured to provide copper ions to the aged catolyte.

7. The copper plating system of claim 5, wherein the cathode chamber comprises a cathode chamber fluid inlet and a cathode chamber fluid outlet configured to circulate sulfuric acid in the cathode chamber.

8. The copper plating system of claim 1, wherein the catolyte electrochemical device comprises:

a housing having a cathode electrode positioned in a first end and an anode electrode positioned in a second end, the second end being oppositely positioned from the first end;

an anode chamber positioned proximate the anode electrode and between the cathode electrode and the anode electrode configured to provide copper ions to an aged catolyte solution;

a cathode chamber positioned proximate the cathode electrode and between the cathode electrode and the anode chamber configured to neutralize acid in the aged catolyte solution; and

an input chamber positioned between the anode and cathode chambers and configured to receive the aged catolyte solution.

9. The copper plating system of claim 8, wherein the input chamber comprises:

a cathodic membrane positioned on a cathode side of the input chamber configured to receive hydrogen ions from the input chamber;

a cathodic membrane positioned on an anode side of the input chamber configured to provide copper ions to the input chamber; and

an input chamber fluid outlet configured to dispense restored electrolyte therefrom.

10. The copper electrochemical plating system of claim 9, wherein the cathode chamber comprises a cathode chamber fluid inlet and a cathode chamber fluid outlet configured to circulate sulfuric acid in the cathode chamber.

11. The copper plating system of claim 9, wherein the anode chamber comprises an anode chamber fluid inlet and an anode chamber fluid outlet configured to circulate a copper sulfate solution in the anode chamber.

12. The copper plating system of claim 9, wherein the cationic membrane positioned on the cathode side of the input chamber is selective to hydrogen ions.

13. The copper plating system of claim 8, wherein the input chamber comprises:

a bipolar membrane positioned on a cathode side of the input chamber configured to receive hydrogen ions from the input chamber and provide hydroxide ions to the input chamber;

a cathodic membrane positioned on an anode side of the input chamber configured to provide copper ions to the input chamber; and

an input chamber fluid outlet configured to dispense restored electrolyte therefrom.

14. The copper plating system of claim 8, wherein the input chamber comprises:

a bipolar membrane positioned on a cathode side of the input chamber configured to receive hydrogen ions from the input chamber and provide hydroxide ions to the input chamber;

an anodic membrane positioned on an anode side of the input chamber configured to receive sulfate ions from the input chamber;

an input chamber fluid outlet configured to dispense restored electrolyte therefrom; and

a control device configured to correct the copper concentration in the restored electrolyte.

15. The copper plating system of claim 14, wherein copper sulfate is added to the restored electrolyte in an amount determined by the control device.

16. The copper plating system of claim 1, wherein the catolyte electrochemical device comprises:

a housing having a cathode electrode positioned in a first end and an anode electrode positioned in a second end, the second end being oppositely positioned from the first end;

an anode chamber positioned proximate the anode and between the cathode electrode and the anode electrode configured to neutralize acid in the aged catolyte solution;

a cathode chamber positioned proximate the cathode electrode and between the cathode electrode and the anode chamber configured to neutralize acid in the aged catolyte solution;

at least one input chamber positioned between the cathode electrode and the anode chamber configured to receive aged catolyte;

at least one copper feed chamber positioned between the input chamber and the anode chamber configured to provide copper ions to the aged catolyte; and

at least one isolation chamber positioned between the input chamber and the copper feed chamber to neutralize acid in the aged catolyte solution.

17. The copper plating system of claim 16, wherein the copper feed chamber comprises a feed chamber fluid inlet and a feed chamber fluid outlet configured to circulate copper sulfate in the copper feed chamber.

18. The copper plating system of claim 16, wherein sulfuric acid is circulated between the isolation chamber, the anode chamber, and the cathode chamber.

19. The copper plating system of claim 16, wherein a copper sulfate solution is added to the restored catolyte.

20. The copper plating system of claim 16, wherein the anode electrode is insoluble.

21. The copper plating system of claim 16, wherein the input chamber comprises:

an anionic membrane positioned on a cathode side of the anode chamber configured to receive sulfate ions from the copper feed chamber;

a cationic membrane positioned between the copper feed chamber and the input chamber configured to provide copper ions to the input chamber;

a bipolar membrane positioned between the input chamber and the isolation chamber configured to proved hydroxide ions to the input chamber and to receive hydroxide ions from the input chamber;

an anionic membrane positioned between the isolation chamber and the feed chamber configured to receive sulfate ions from the feed chamber; and

a bipolar membrane positioned between the cathode chamber and the feed chamber configured to provide hydroxide ions to the input chamber and receive hydrogen ions from the input chamber.

22. The copper plating system of claim 1, wherein the catolyte electrochemical device comprises:

a housing having a cathode electrode positioned in a first end and an anode electrode positioned in a second end, the second end being oppositely positioned from the first end;

an anode chamber positioned proximate the anode and between the cathode electrode and the anode electrode configured to neutralize acid in the aged catolyte solution;

a cathode chamber positioned proximate the cathode electrode and between the cathode electrode and the anode chamber configured to neutralize acid in the aged catolyte solution;

at least one input chamber positioned between the cathode electrode and the anode chamber configured to receive aged catolyte; and

at least one purification chamber positioned between the input chambers to neutralize acid in the aged catolyte solution.

23. The copper plating system of claim 22, wherein sulfuric acid is circulated between the anode chamber, the purification chamber, and the cathode chamber.

24. The copper plating system of claim 22, wherein a copper sulfate solution is added to the restored catolyte.

25. The copper plating system of claim 22, wherein the anode electrode is insoluble.

26. The copper plating system of claim 22, wherein the input chamber comprises:

an anionic membrane positioned on a cathode side of the anode chamber configured to receive sulfate ions from the input chamber;

a bipolar membrane positioned between the input chamber and the purification chamber configured to provide hydroxide ions to the input chamber and to receive hydroxide ions from the input chamber;

an anionic membrane positioned between the purification chamber and the input chamber configured to receive sulfate ions from the input chamber; and

an anionic membrane positioned between the cathode chamber and the purification chamber configured to provide hydroxide ions to the purification chamber.

27. The copper plating system of claim 22, further comprising an electrodialysis chamber configured to remove contaminants from the restored catolyte.

28. The copper plating system of claim 22, further comprising a catolyte storage tank in fluid communication with a catolyte electrochemical device configured to receive a portion of catolyte solution and correct a catolyte concentration.

29. The copper plating system of claim 22, further comprising a column comprising copper oxide in fluid communication with the anode chamber configured to correct an anolyte concentration.

30. A method for plating copper, comprising:

supplying an electrolyte solution to a copper plating cell;

plating copper onto a substrate in the plating cell with the electrolyte solution;

removing aged electrolyte solution from the plating cell; and

neutralizing a portion of the aged electrolyte solution with an electrochemical device.

31. The method of claim 30, wherein neutralizing a portion of the aged electrolyte with an electrochemical device comprises:

receiving the aged electrolyte solution in a first end of a anode chamber;

urging positive copper ions to diffuse from a soluble anode into the aged electrolyte solution;

urging positive hydrogen ions to diffuse through a bipolar membrane towards a cathode into a cathode chamber;

urging negative hydroxide ions to diffuse through the bipolar membrane towards an anode into the anode chamber; and

removing a copper sulfate solution from the concentration chamber.

32. The method of claim 31, wherein the urging steps comprise applying an electrical bias across the electrodialysis cell.

33. The method of claim 31, further comprising circulating a sulfuric acid solution through the cathode chamber.

34. The method of claim 30, wherein neutralizing a portion of the aged electrolyte with an electrochemical device comprises:

receiving the aged electrolyte solution in a first end of an input chamber;

urging positive copper ions to diffuse from a soluble anode in an anode chamber through a cationic membrane into the aged electrolyte solution;

urging positive hydrogen ions to diffuse through a cationic membrane towards a cathode into a cathode chamber; and

removing a copper sulfate solution from the concentration chamber.

35. The method of claim 34, wherein the urging steps comprise applying an electrical bias across the electrochemical device.

36. The method of claim 34, further comprising circulating a sulfuric acid solution through the cathode chamber.

37. The method of claim 31, wherein neutralizing a portion of the aged electrolyte with an electrochemical device comprises:

receiving the aged electrolyte solution in a first end of an input chamber;

urging negative sulfate ions to diffuse through an anionic membrane towards an anode into an anode chamber;

urging positive hydrogen ions to diffuse through a bipolar membrane towards a cathode into a cathode chamber; and

urging negative hydrogen ions to diffuse through the bipolar membrane away from the cathode into the input chamber; and

removing a copper sulfate solution from the concentration chamber.

38. The method of claim 37, wherein the urging steps comprise applying an electrical bias across the electrochemical device.

39. The method of claim 37, further comprising circulating a sulfuric acid solution through the cathode chamber.

40. The method of claim 37, further comprising adding a copper sulfate solution to the restored electrolyte.

41. The method of claim 31, wherein neutralizing a portion of the aged electrolyte with an electrochemical device comprises:

receiving the aged electrolyte solution in an input chamber;

urging negative sulfate ions to diffuse through an anionic membrane towards an anode into an anode chamber;

urging positive copper ions to diffuse through a cationic membrane from a copper feed chamber into the aged electrolyte solution;

urging positive hydrogen ions to diffuse through a bipolar membrane towards a cathode from the aged electrolyte solution into an isolation chamber;

urging negative hydroxide ions to diffuse through the bipolar membrane towards an anode from the isolation chamber into the aged electrolyte; and

removing a copper sulfate solution from the concentration chamber.

42. The method of claim 31, wherein the urging steps comprise applying an electrical bias across the electrochemical device.

43. The method of claim 31, further comprising circulating a sulfuric acid solution through the cathode chamber, the isolation chamber, and the anode chamber.

44. The method of claim 31, further comprising circulating a copper sulfate solution through the copper feed chamber.

45. The method of claim 31, wherein neutralizing a portion of the aged electrolyte with an electrochemical device comprises:

receiving the aged electrolyte solution in an input chamber;

urging negative sulfate ions to diffuse through an anionic membrane towards an anode in the anode chamber;

urging positive hydrogen ions to diffuse through a bipolar membrane towards a cathode from the aged electrolyte into a purification chamber;

urging negative hydroxide ions to diffuse through a bipolar membrane from the purification chamber into the aged electrolyte; and

removing a copper sulfate solution from the concentration chamber.

46. The method of claim 45, wherein the urging steps comprise applying an electrical bias across the electrochemical device.

47. The method of claim 45, further comprising circulating a sulfuric acid solution through the cathode chamber, the purification chamber, and the anode chamber.

48. The method of claim 45, further comprising passing the copper sulfate solution through an electrodialysis cell to further remove contaminants and add copper ions to the solution.