Electroplating system and method with increased metal ion concentration

Abstract

An electroplating method may include providing an initial anolyte to a first compartment of an electrochemical cell. These methods may include providing an initial catholyte to a second compartment of the electrochemical cell. The initial catholyte may be characterized by an initial catholyte metal ion concentration less than an initial anolyte metal ion concentration in the initial anolyte. These methods may include providing an acidic solution to a third compartment of the electrochemical cell. The acidic solution may be characterized by an initial pH. These methods may include applying a current to an anode of an electrochemical cell. Application of current to the anode may increase the initial catholyte metal ion concentration in the initial catholyte and decrease the pH of the acidic solution.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Application Serial No. 63 / 327,268, filed on April 4, 2022, which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] The present technology relates to electroplating operations in semiconductor processing. More particularly, the present technology relates to systems and methods for performing enrichment and replenishment of electroplating systems. Background Art

[0004] Integrated circuits can be manufactured by processes that create alternating patterned layers of material on a substrate surface. After formation, etching, and other processing on the substrate, metal or other conductive materials are often deposited or formed to provide electrical connections between components. Because this metallization can be performed after many manufacturing operations, problems caused during metallization can result in expensive scrapped substrates or wafers.

[0005] Electroplating is performed in a plating chamber, where the device side of the wafer is in a liquid electrolyte bath, and the electrical contacts on the contact ring contact the conductive layer on the surface of the wafer. Current passes through the electrolyte and the conductive layer. Metal ions in the electrolyte plate out onto the wafer, forming a metal layer on the wafer. Plating chambers generally have consumable anodes, which are advantageous for plating bath stability and cost of ownership. For example, copper consumable anodes are commonly used when electroplating copper. Copper ions removed from the plating bath are replenished by copper removed from the anode, thereby maintaining the metal concentration in the plating bath. Although efficient in replacing the plated metal ions, the use of consumable anodes requires a more complex and expensive design to allow the consumable anodes to be replaced. Even more complexity is added when the consumable anode is combined with a diaphragm to avoid degrading the quality of the electrolyte or to avoid oxidation of the consumable anode during idle operation.

[0006] Therefore, there is a need for improved systems and methods that can be used to produce high quality devices and structures while protecting both the substrate and the electroplating bath. The present technology can address these and other needs. Summary of the invention

[0007] Embodiments of the present technology include electroplating methods that include providing a first portion of an electrolyte raw material to a first compartment of an electrochemical cell. The first portion of the electrolyte raw material may be characterized by an initial metal ion concentration and an initial acid concentration. The methods may include providing a second portion of the electrolyte raw material to a second compartment of the electrochemical cell. The second portion of the electrolyte raw material may be characterized by an initial metal ion concentration. The second compartment and the first compartment may be separated by a first diaphragm. The methods may include providing an acidic solution to a third compartment of the electrochemical cell. The third compartment and the second compartment may be separated by a second diaphragm. The acidic solution may be characterized by an initial acid concentration. The methods may include applying an electric current to an anode of the electrochemical cell. The anode of the electrochemical cell may be disposed proximate to the first compartment and opposite to the first diaphragm.

[0008] In some embodiments, the electrolyte raw material may be characterized by a copper concentration of less than or about 65.0 g / L. The electrolyte raw material may be characterized by an acid concentration of greater than or about 90.0 g / L. The acidic solution may be or include sulfuric acid. These methods may include evaporating a portion of the second portion of the electrolyte raw material when applying an electric current to the anode of the electrochemical unit. These methods may include adding a second acidic solution to the second compartment. The second acidic solution may be less than or about the amount of the portion evaporated from the second portion of the electrolyte raw material. These methods may include forming an anode electrolyte from a first portion of the electrolyte raw material in the first compartment. The anode electrolyte may be characterized by a copper concentration of greater than or about 60.0 g / L. The anode electrolyte may be characterized by an acid concentration of less than or about 20.0 g / L. These methods may include forming a cathode electrolyte from a second portion of the electrolyte raw material in the second compartment. The cathode electrolyte may be characterized by a copper concentration of greater than or about 60.0 g / L. The cathode electrolyte may be characterized by an acid concentration of greater than or about 90.0 g / L. The temperature may be maintained at greater than or about 40° C. These methods may include removing a portion of the acidic solution from the third compartment and replacing it with a new acidic solution. This new acidic solution can maintain the acid concentration in the third compartment. These methods can include adding a third acidic solution to the cathode electrolyte to increase the acid concentration in the cathode electrolyte. These methods can include adding one or more chemical additives to the cathode electrolyte.

[0009] Embodiments of the present technology may include electroplating methods. These methods may include providing a first portion of an electrolyte raw material to a first compartment of an electrochemical cell. These methods may include providing a second portion of an electrolyte raw material to a second compartment of the electrochemical cell. The second compartment and the first compartment may be separated by a first diaphragm. These methods may include providing an acidic solution to a third compartment of the electrochemical cell. The third compartment and the second compartment may be separated by a second diaphragm. These methods may include heating the electrochemical cell to a temperature greater than or about 40° C. These methods may include applying an electric current to an anode of the electrochemical cell. The anode of the electrochemical cell may be disposed adjacent to the first compartment and opposite to the first diaphragm. These methods may include forming an anode electrolyte from a first portion of the electrolyte raw material and forming a cathode electrolyte from a second portion of the electrolyte raw material. The anode electrolyte and the cathode electrolyte may be formed simultaneously in the electrochemical cell.

[0010] In some embodiments, a portion of the first portion of the electrolyte material in the first compartment may migrate through the first diaphragm. These methods may include adding deionized water to the first compartment to compensate for the migration of the first portion of the electrolyte material through the first diaphragm. The first portion of the electrolyte material may be or include the remaining anolyte. Forming the anolyte and cathode electrolyte may be completed in less than or about 24 hours.

[0011] Embodiments of the present technology may include electroplating methods. These methods may include providing a first portion of an electrolyte raw material to a first compartment of an electrochemical cell. The first compartment may have a capacity greater than or about 200 L. These methods may include providing a second portion of the electrolyte raw material to a second compartment of the electrochemical cell. The second compartment and the first compartment may be separated by a first diaphragm. The second compartment may have a capacity greater than or about 250 L. These methods may include providing an acidic solution to a third compartment of the electrochemical cell. The third compartment and the second compartment may be separated by a second diaphragm. The third compartment may have a capacity less than or about 50 L. These methods may include heating the electrochemical cell. These methods may include applying an electric current to an anode of the electrochemical cell. The anode of the electrochemical cell may be disposed proximate to the first compartment and opposite to the first diaphragm. These methods may include forming an anode electrolyte and a cathode electrolyte.

[0012] In some embodiments, heating the electrochemical cell may include heating the electrochemical cell to a temperature greater than or about 40° C. The anolyte and the cathode electrolyte may be formed simultaneously in the electrochemical cell. The methods may include replacing a portion of the acidic solution in the third compartment to maintain the acid concentration in the acidic solution. The first separator and the second separator may include different separator materials.

[0013] This technique can provide several advantages over conventional techniques. For example, the present technique can generate and maintain an electroplating operation at a high metal ion concentration, thereby increasing the rate at which the metal is electroplated on the substrate. In addition, the present technique can simultaneously prepare and / or replenish the anolyte and the catholyte for a continuous electroplating operation. These and other embodiments and many of their advantages and features are described in more detail in conjunction with the following description and accompanying drawings.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A further understanding of the nature and advantages of the disclosed embodiments may be obtained by referring to the remaining portions of the specification and the accompanying drawings.

[0016] Figure 1 A schematic diagram of an electroplating processing system according to some embodiments of the present technology is illustrated.

[0017] Figure 2 Illustrated are exemplary operations in a method of operating an electroplating system according to some embodiments of the present technology.

[0018] Figure 3 Schematic diagram illustrating supplemental components according to some embodiments of the present technology.

[0019] Several drawings are included as schematic diagrams. It will be understood that the drawings are for illustrative purposes and are not to be considered to be to scale unless specifically noted that the drawings are to scale. Additionally, the drawings are provided as schematic diagrams to aid understanding and may not include all aspects or information compared to actual representations and may include exaggerated material for illustrative purposes.

[0020] In the drawings, similar elements and / or features may have the same numerical reference symbol. In addition, multiple elements of the same kind may be distinguished by adding a letter that distinguishes the similar elements and / or features after the reference symbol. If only the leading numerical reference symbol is used in the specification, the description applies to any similar element and / or feature having the same leading numerical reference symbol, regardless of the suffix letter. DETAILED DESCRIPTION

[0021] The metal deposition rate of many electroplated metals increases with higher metal ion concentrations in the aqueous solution. Conventional techniques for increasing the metal ion concentration of aqueous electroplating solutions include adding more initial liquid to the electroplating solution and evaporating some of the water from the solution. Unfortunately, this technique can cause problems for electroplating systems that use an anolyte and a catholyte solution separated by an ion-selective membrane that allows metal ions to pass from the anolyte to the catholyte where the electroplated metal is located on the substrate surface. Additionally or alternatively, the metal ion concentration can be increased by dissolving a metal-containing material into the electroplating solution, such as a salt. Unfortunately, this option is not always feasible in a wafer fab environment.

[0022] In an electroplating system that includes both an anolyte and a catholyte solution, increasing the metal ion concentration is usually targeted at the catholyte because it is in direct contact with the plating surface of the substrate. For most initial liquids, increased metal ions are also accompanied by increased acid. High acid concentrations in the anolyte may reduce the amount of metal ions transported through the ion-selective membrane that separates the anolyte from the catholyte. Therefore, metal ion transport may depend on the acid concentration in the anolyte.

[0023] The ion selective membrane itself may also cause an acid imbalance by favoring the transfer of hydrogen ions from the anolyte to the cathode electrolyte over the transfer of metal ions. Over time, the ion selective membrane results in a weakly acidic anolyte that is more concentrated in metal ions. During electroplating, metal ions in the anolyte may be transferred through the ion selective membrane. At the same time, the metal ions in the anolyte may be replenished by the dissolution of a consumable anode near the anolyte. The dissolution of the consumable anode may increase the metal ions in the anolyte at a higher rate than the metal ions passing through the ion selective membrane.

[0024] Embodiments of the present technology address these problems by generating and maintaining the plating solution at a high metal ion concentration, which increases the rate of plating of the metal on the substrate. The present technology can simultaneously prepare and / or replenish the anolyte and catholyte for continuous plating operations. In embodiments, a three-compartment replenishment assembly can simultaneously prepare anolyte and catholyte solutions with increased metal ion concentrations. Simultaneous preparation can reduce downtime of the electroplating system and can increase the yield of electroplated substrates and / or wafers. Furthermore, embodiments of the present technology can use existing hardware, reducing the need for additional equipment.

[0025] Figure 1An exemplary electroplating system 10 is shown. In the system 10, the electrolyte feedstock may be added directly to the cathode electrolyte 14 in the electroplating chamber 13, and / or directly to the cathode electrolyte in the cathode electrolyte container 11. In embodiments, when the electrolyte feedstock is added directly to the cathode electrolyte 14 in the electroplating chamber, and / or directly to the cathode electrolyte in the cathode electrolyte container 11, some remaining cathode electrolyte may be present in the cathode electrolyte container 11, and this addition may adjust the cathode electrolyte concentration of the metal ions to the initial concentration of the metal ions. For example, the initial concentration of the metal ions in the cathode electrolyte 14 may be less than or about 70.0 g / L, and may be less than or about 67.5 g / L, less than or about 62.5 g / L, less than or about 60.0 g / L, less than or about 57.5 g / L, less than or about 55.0 g / L, less than or about 52.5 g / L, less than or about 50.0 g / L, or less.

[0026] In some embodiments, the system 10 may be substantially drained of the cathode electrolyte prior to adding the electrolyte feedstock, which addition represents filling or refilling the system's cathode electrolyte at the beginning of the electroplating process. In these embodiments, the concentration of metal ions in the cathode electrolyte 14 is the metal ion concentration of the electrolyte feedstock. In additional embodiments, as previously described, the electrolyte feedstock may be added to the system 10 that already contains the cathode electrolyte. Depending on the metal ion concentration of the pre-existing cathode electrolyte in the system 10, the addition of the electrolyte feedstock may reduce the metal ion concentration to reach a first metal ion concentration in the cathode electrolyte.

[0027] Similarly, the electrolyte feedstock may be added directly to the anode electrolyte 16 in the electroplating chamber 13, and / or directly to the anode electrolyte in the anode electrolyte container 12. In embodiments, the addition of the electrolyte feedstock may adjust the anode electrolyte concentration of the metal ions to an initial concentration of the metal ions that is substantially the same as the concentration of the metal ions in the electrolyte feedstock. In other embodiments, the initial concentration of the metal ions in the anode electrolyte 16 may be less than or about 70.0 g / L, and may be less than or about 67.5 g / L, less than or about 62.5 g / L, less than or about 60.0 g / L, less than or about 57.5 g / L, less than or about 55.0 g / L, less than or about 52.5 g / L, less than or about 50.0 g / L, or less.

[0028] In an embodiment, the initial concentration of metal ions in the cathode electrolyte 14 may be the same as the initial concentration of metal ions in the anode electrolyte 16 because the electrolyte raw materials used in both the cathode electrolyte 14 and the anode electrolyte 16 may be a virgin makeup solution (VMS). For example, the VMS may be characterized by a metal ion concentration of about 55.0 g / L and an acid concentration of about 100 g / L, such as a copper ion concentration. Although the electrolyte raw materials used for both the cathode electrolyte 14 and the anode electrolyte 16 may be the same material having the same metal ion concentration and the same acid concentration, such as VMS, the electrolyte raw materials used for the cathode electrolyte 14 and the electrolyte raw materials used for the anode electrolyte 16 may also have different metal ion concentrations and / or acid concentrations. As previously described, some remaining cathode electrolyte and / or anode electrolyte may be present in the electroplating chamber 13, which may change the metal ion concentration and / or acid concentration.

[0029] In some embodiments, the system 10 may substantially drain the anolyte prior to adding electrolyte feedstock, which addition represents filling or refilling the system's anolyte at the start of the electroplating process. In these embodiments, the concentration of metal ions in the anolyte 16 is the metal ion concentration of the electrolyte feedstock. In additional embodiments, electrolyte feedstock may be added to the system 10 already containing an anolyte. In these embodiments, this addition adjusts the concentration of metal ions in the anolyte 16 or anolyte container 12 to be closer to the metal ion concentration in the electrolyte feedstock. Depending on the metal ion concentration of the pre-existing anolyte in the system 10, adding electrolyte feedstock may reduce the metal ion concentration to reach a first metal ion concentration in the anolyte.

[0030] Metal ions may refer to metal ions that can be electroplated into metal on a substrate, and the substrate fluid contacts the cathode electrolyte. It should be understood that the electrolyte raw material, the cathode electrolyte 14, and the anode electrolyte 16 may include other metal ions (for example, ions of alkali metals and alkaline earth metals), which are not included in the metal ion concentration because they are not electroplated into metal on the substrate. The metal ions may include other types of metal ions such as copper ions, tin ions, and nickel ions. These metal ions can be electroplated into metal layers of copper, tin, and nickel on the surface of the substrate, respectively. The metal ions may be dissolved ions of metal salts that are at least partially soluble in water. The metal salt may include copper sulfate (CuSO4) and copper chloride (CuCl2) or other metal salts. The cathode electrolyte and the anode electrolyte may be aqueous solutions or mixtures including metal ions. In addition to the metal ions, the cathode electrolyte may include one or more additives, such as inhibitors, accelerators, and levelers or other additives. The anode electrolyte may lack at least one additive in the cathode electrolyte.

[0031] In an embodiment, the metal ion concentration can be measured by a metal ion sensor 105a, which is located in the plating chamber 13 and in fluid contact with the cathode electrolyte 14. During the portion of the electroplating operation in which the metal ions are plated on the substrate, the metal ion concentration in the cathode electrolyte 14 decreases. The magnitude of the decrease depends on several factors, including the surface area of ​​the (single or multiple) substrates being plated, the volume of the cathode electrolyte, the amount of current passing through the electrodes of the system 10, and the metal ion transfer rate between the anolyte and the cathode electrolyte, or other factors. The metal ion transfer rate is further affected by several factors, including the absolute and relative metal ion concentrations in the cathode electrolyte and the anolyte, the acidity (pH) of the cathode electrolyte and the anolyte, and the difference in acidity between the cathode electrolyte and the anolyte. The acid concentration in the anolyte can primarily determine the transfer rate of metal ions through the diaphragm.

[0032] In embodiments, the measurement of the metal ion concentration in the cathode electrolyte 14 may be performed continuously or may be performed at intervals before, during, and after the electroplating of the metal on the substrate. In other embodiments, the measurement of the metal ion concentration in the cathode electrolyte 14 may measure the decrease in metal ion concentration from a first metal ion concentration immediately following the addition of electrolyte feedstock to a second metal ion concentration that is less than the first metal ion concentration. When the measurement finds that the metal ion concentration has decreased to the second metal ion concentration or less, a signal may be transmitted from the sensor 15a to increase the metal ion concentration in the cathode electrolyte 14.

[0033] It should be understood that the metal ion concentration measurement may be performed at a location in the system 10 other than the cathode electrolyte 14 in the electroplating chamber 13. In an embodiment, the metal ion concentration may be measured in the cathode electrolyte contained in the cathode electrolyte container 11 by a metal ion sensor 15b in contact with the cathode electrolyte. The change in the metal ion concentration in the cathode electrolyte contained in the cathode electrolyte container 110 is smaller than that in the cathode electrolyte 14 contained in the electroplating chamber 13. The change in metal ion concentration can be measured more quickly in the cathode electrolyte 14 than in the cathode electrolyte contained in the cathode electrolyte container 11. The metal ion measurement may be performed in both the cathode electrolyte 14 contained in the electroplating chamber 13 and the cathode electrolyte container 11.

[0034] In an embodiment, the pH may be measured by a sensor 15a, which is also capable of measuring the metal ion concentration in the cathode electrolyte 14. In other embodiments, the pH may be measured by a sensor (not shown) independent of the sensor 15a, such as a dedicated pH meter. In more embodiments, the measured cathode electrolyte pH may further include generating a pH signal from a pH sensor, which is in electronic communication with a logic processor (not shown). When the sensor indicates that the cathode electrolyte pH is above or below a threshold level, the logic processor may generate a signal to perform one or more operations to increase the cathode electrolyte pH. The cathode electrolyte pH that causes the logic processor to generate a signal to initiate the one or more pH reduction operations may be greater than or about 0.0, greater than or about 0.1, greater than or about 0.2, greater than or about 0.3, greater than or about 0.4, greater than or about 0.5, greater than or about 0.6, greater than or about 0.7, greater than or about 0.8, greater than or about 0.9, greater than or about 1.0, or greater. The cathode electrolyte pH that causes the logic processor to generate a signal to initiate one or more pH increase operations may be less than or about 0.5, less than or about 0.4, less than or about 0.3, less than or about 0.2, less than or about 0.1, less than or about 0.0, less than or about -0.1, less than or about -0.2, less than or about -0.3, less than or about -0.4, less than or about -0.5, less than or about -0.6, or less.

[0035] In system 10, the anolyte pH may be measured by one or more sensors 15c and 15d, which contact the anolyte 16 in the plating chamber 13 and the anolyte in the anolyte container 12, respectively. When the sensor 15c or 15d indicates that the anolyte pH is at or above a threshold level, the logic processor may generate a signal to perform one or more operations to reduce the anolyte pH. The anolyte pH that causes the logic processor to generate a signal to initiate one or more pH reduction operations may be greater than or about 3.0, greater than or about 3.1, greater than or about 3.2, greater than or about 3.3, greater than or about 3.4, greater than or about 3.5, greater than or about 3.7, greater than or about 3.8, greater than or about 3.9, greater than or about 4.0, or greater.

[0036] As described above, electroplating includes removing metal ions from a cathode electrolyte in contact with a substrate fluid as the ions are reduced to a metal layer on the substrate. Removing the electroplated metal ions from the cathode electrolyte causes the metal ion concentration in the cathode electrolyte to decrease. In an electroplating system according to an embodiment of the present technology, such as system 10, metal ions migrate from the anode electrolyte 16 through the ion selective membrane 18 to replenish a majority of the metal ions in the cathode electrolyte, and the ion selective membrane 18 selectively allows cations to pass and blocks the migration of other components of the anode electrolyte and the cathode electrolyte. In an embodiment, these other components may include cathode electrolyte additives, such as inhibitors (for example, polyethylene glycols), accelerators (for example, bis-(3-sulfopropyl)-disulfide), and levelers (for example, Janus Green B dye), which help to electroplate a uniform metal layer on the substrate. The ion-selective membrane 18 can prevent the additives from passing through the membrane with the cations and, for example, forming a film on the oppositely charged electrode (for example, negatively charged additives forming a film on the anode).

[0037] In many embodiments, metal ions migrate through the ion selective membrane 108 faster than hydrogen ions (H + ) migrates slowly through the diaphragm. Over time, replenishing the electroplated metal ions in the cathode electrolyte 14 with the metal ions in the anode electrolyte 16 increases the concentration gradient between the cathode electrolyte and the anode electrolyte. This also increases the acid concentration of the cathode electrolyte. Alternatively, if more protons pass through the second diaphragm and into the third compartment than pass through the first diaphragm from the first compartment, the acid concentration of the cathode electrolyte may not increase.

[0038] In embodiments, the electroplating system 10 may include additional elements that facilitate the electroplating operation. In additional embodiments, the electroplating system 10 may include a supplemental assembly 20 that provides additional metal ions to the anolyte and / or catholyte during the electroplating operation. The supplemental assembly 20 may include an anolyte chamber 22, a catholyte chamber 26, and a third chamber 28, the third chamber 28 contacting a cathode 35. The anolyte chamber 22 and the catholyte chamber 26 may be fluidly separated by a first ion selective membrane 30, which may be operable to allow metal ions and hydrogen ions to pass from the anolyte chamber 22 to the catholyte chamber 26. The first ion selective membrane 30 may slow down or block the transfer of additives between the catholyte chamber 26 and the anolyte chamber 22. The catholyte chamber 26 and the third chamber 28 may be fluidly separated by a second cation selective membrane 32, which may be operable to allow hydrogen ions to pass from the catholyte chamber 26 to the third chamber 28. In an embodiment, the second cation selective membrane 32 can be the same material as the first ion selective membrane 32. Alternatively, the membranes can be different, and for example, the second cation selective membrane 32 can be a monovalent membrane that selectively transmits H+ ions. However, a monovalent membrane that selectively transmits H+ ions can still allow some amount of Cu++ to pass through the membrane. The second ion selective membrane 32 can slow down or block the migration of metal ions and additives from the cathode electrolyte chamber 26 to the third chamber 28.

[0039] In embodiments, the anolyte chamber 22 may include a first chamber 23 to house an anode material that produces additional metal ions for an anode electrolyte contained in a second chamber 25 that is fluidly contacted with the anode material. The anode material in the first chamber 23 may also serve as an anode electrically connected to a cathode 35 that is fluidly contacted with a cathode electrolyte in a third chamber 28. A portion of the metal ions produced by the anode material may be added to the cathode electrolyte in the cathode electrolyte container 11 and / or the anolyte in the anode electrolyte container 12. The additional metal ions help maintain the concentration of metal ions in the cathode electrolyte and the anode electrolyte in the plating chamber 13 and containers 11 and 12 during the electroplating operation.

[0040] Figure 2 The exemplary operations in the method 200 of operating an electroplating system according to some embodiments of the present technology are illustrated. However, it is contemplated that Figure 2 The operations shown in are only one embodiment, and the operations may be performed in any order or sequence. This method may be performed in a variety of processing systems, including electroplating systems according to embodiments of the present technology described below, including Figure 30048] An exemplary supplemental assembly 74 is illustrated in FIG. This figure illustrates an enlarged schematic view of a supplemental assembly 74 as an operational element that may be adapted for use with any number of specific supplemental assembly configurations.

[0041] The method may include providing a supplemental assembly anolyte (e.g., electrolyte raw material) to a supplemental assembly anolyte compartment 98, which may be a first compartment of a supplemental assembly 74, at operation 205. The first compartment may have a capacity greater than or about 200 L. The electrolyte raw material in the anolyte compartment 98 may be or include a residual anolyte from a previous electroplating operation. The electrolyte raw material in the anolyte compartment may be characterized by an initial concentration of metal ions. The anolyte may circulate in the supplemental assembly 74 through a supplemental assembly anolyte loop 90, which includes the anolyte compartment 98, and an optional supplemental assembly anolyte tank 96. The method may include providing a supplemental assembly catholyte (e.g., electrolyte raw material) to a supplemental assembly catholyte compartment 106, which may be a second compartment of a supplemental assembly 74, at operation 210. The second compartment may have a capacity greater than or about 250 L, and may have a capacity greater than or about 300 L, greater than or about 350 L, or greater. The electrolyte feedstock in the cathode electrolyte compartment 106 may be characterized by an initial concentration of metal ions. A cathode electrolyte return line 72 may be connected to one side of the cathode electrolyte compartment 106, and a cathode electrolyte supply line 78 may be connected to the other side of the cathode electrolyte compartment 106, which may allow the cathode electrolyte to circulate through the cathode electrolyte compartment 106. Alternatively, the cathode electrolyte flow loop through the replenishment assembly 74 may be a separate flow loop from the cathode electrolyte cell (e.g., cathode electrolyte cell 110).

[0042] The metal ion concentration of the electrolyte raw material can be characterized by a copper concentration of less than or about 80.0 g / L, such as less than or about 87.5 g / L, less than or about 85.0 g / L, less than or about 82.5 g / L, less than or about 80.0 g / L, less than or about 77.5 g / L, less than or about 75.0 g / L, less than or about 72.5 g / L, less than or about 70.0 g / L, or less. The electrolyte raw material can be characterized by an acid concentration of greater than or about 90.0 g / L, such as greater than or about 92.5 g / L, greater than or about 95.0 g / L, greater than or about 97.5 g / L, greater than or about 100.0 g / L, or greater.

[0043] In some embodiments, such as for copper plating, the replenishment assembly anolyte may be a copper sulfate electrolyte, although it will be appreciated that the system may be used for any number of electroplating operations utilizing chemistries and materials suitable for the electroplating operation. The anolyte replenishment assembly in replenishment assembly 74 may not require a recirculation loop and may include only the anolyte compartment 98. A gas sparger, such as a nitrogen sparger, may provide agitation to the replenishment assembly without requiring a complex recirculation loop requiring piping and pumps. Referring again to the copper plating system, as a non-limiting example, in the case of using a low acid electrolyte or anolyte, when current is passed through the replenishment assembly, the Cu 2+ Ions may be transported or moved across the membrane into the cathode electrolyte instead of protons. Gas sparging may also reduce oxidation of the bulk copper material.

[0044] The deionized water supply line 124 can supply make-up deionized water to the supplementary component anode electrolyte tank 96 or the supplementary component anode electrolyte compartment 98. Bulk plating material 92, such as copper particles, can be provided in the supplementary component anode electrolyte compartment 98 and provide a material that can be plated onto the wafer 50. A pump can circulate the supplementary component anode electrolyte through the supplementary component anode electrolyte compartment 98. The supplementary component anode electrolyte can be completely separated from the anode electrolyte provided to the anode 40 and / or 42. In addition, in some embodiments, the anode electrolyte compartment 98 can be used without any supplementary component anode electrolyte loop 90. For example, a gas sparger or some other pumping system can provide agitation to the anode electrolyte compartment 98 without using a supplementary component anode electrolyte loop. For example, some embodiments of the anode electrolyte compartment or the first compartment may include an anode electrolyte replenishment tank, or may simply circulate the anode electrolyte in the compartment or in two parts of the compartment, as will be further described below.

[0045] In the replenishing assembly 74, a first cation membrane 104 may be located between the anolyte compartment 98 and the cathode electrolyte compartment 106 to separate the replenishing assembly anolyte from the cathode electrolyte. The first cation membrane 104 allows metal ions and water to pass through the replenishing assembly anolyte compartment 98 into the cathode electrolyte in the cathode electrolyte compartment 106, while otherwise providing a barrier between the replenishing assembly anolyte and the cathode electrolyte. Deionized water may be added to the cathode electrolyte to replace water lost by evaporation, but more typically water evaporation may be enhanced to evaporate water from the anolyte replenishing assembly into the cathode electrolyte by electro-osmosis. An evaporator may also be included to help remove excess water.

[0046] The flow of metal ions into the cathode electrolyte can replenish the concentration of metal ions in the cathode electrolyte. In an embodiment, when the metal ions in the cathode electrolyte are deposited onto the wafer 50 to form a metal layer on the wafer 50, the metal ions from the bulk plating material 92 can replace the metal ions in the cathode electrolyte, and the metal ions from the bulk plating material 92 move through the replenishing assembly anode electrolyte and the first diaphragm 104 into the cathode electrolyte flowing through the cathode electrolyte compartment 106 of the replenishing assembly 74. In a further embodiment, the metal ions are added to the cathode electrolyte by directly conveying a portion of the anode electrolyte to the cathode electrolyte through a conduit that bypasses the ion diaphragm.

[0047] The method 200 may include providing an acidic solution to the third compartment 112 at operation 215, which may be the third compartment of the replenishment assembly 74. The third compartment may have a capacity of less than or about 50 L. The first compartment, the second compartment, and the third compartment of the replenishment assembly 74 may together form an electrochemical unit. The acidic solution in the third compartment 112 may selectively circulate through the replenishment assembly tank 118, wherein deionized water and sulfuric acid are added to the replenishment assembly electrolyte through the inlet 122. The electrolyte of the third compartment 112 may include, for example, deionized water with 1-10% sulfuric acid. The acidic solution may be characterized by an initial pH.

[0048] In the supplemental assembly 74, a second cationic membrane 108 may be located between the cathode electrolyte compartment 106 and the third compartment 112 to separate the cathode electrolyte from the acidic solution. The second cationic membrane 108 allows protons (i.e., hydrogen ions) to pass from the cathode electrolyte in the cathode electrolyte compartment 106 to the acidic solution in the third compartment 112, while limiting the amount of metal ions that pass through the membrane, which may then be precipitated on the inert cathode. One function of the third compartment 112 may be to complete the circuit of the supplemental assembly in a manner that metal is not precipitated onto the cathode 114 disposed in the third compartment 112. The third compartment 112 may be used with or without an additional tank or circulation loop. The highly acidic electrolyte or cathode electrolyte bath in the cathode electrolyte compartment 106 ensures that most of the current passing through the membrane 108 is protons rather than metal ions, so that the cathode reaction on the inert cathode 114 is mainly hydrogen evolution. In this way, the current in the supplemental assembly 74 replenishes the copper in the cathode electrolyte while avoiding the loss of copper through the membrane 108. The second cation separator 108 may be the same material as the first cation separator 104 or a different material.

[0049] A cathode 114, such as an inert cathode, may be located in the third compartment 112 and opposite the second cation membrane 108. A negative electrode or cathode of a power source 130, such as a DC power source, may be electrically connected to the cathode 114. A positive electrode or anode of the power source 130 may be electrically connected to the bulk electroplated material 92 or metal in the supplemental assembly anode electrolyte compartment 98, thereby applying or generating a voltage differential across the supplemental assembly 74. The inert cathode 114 may be platinum or a platinum-coated wire or plate. The second ion membrane 108 may help retain copper ions in the second compartment. Additionally, the second ion membrane 108 may be configured to specifically retain Cu ions. 2+ Maintained in the cathode electrolyte. For example, in some embodiments, the second ion membrane can be a monovalent membrane, which can further restrict the passage of copper through the membrane.

[0050] In some embodiments, before applying the current to the supplemental component 74, the method 200 may include heating the supplemental component 74 at optional operation 220. The temperature in the electrochemical cell of the supplemental component 74 may be maintained at greater than or about 40°C, greater than or about 45°C, greater than or about 50°C, or greater. At operation 225, the current may be applied to the anode or bulk plating material 92. In embodiments, operation 225 may include applying the current for a fixed period of time to deliver the desired charge. Applying the current to the anode may increase the initial concentration of the metal ions in the electrolyte raw material in the second compartment of the electrochemical cell, while the concentration of the metal ions in the third compartment may not change or be relatively stable. For example, the concentration of the metal ions in the third compartment of the electrochemical cell may change by less than or about 5%, and may change by less than or about 4%, less than or about 3%, less than or about 2%, less than or about 1%, less than or about 0.5%, or less.

[0051] As previously described, water may evaporate from the cathode electrolyte in the cathode electrolyte compartment 106 during method 200, such as during optional operation 230, which may be intentional to compensate for water transport through the first ion selective membrane 30 and concentrate the cathode electrolyte. The evaporation may cause concentration of the cathode electrolyte in the cathode electrolyte compartment 106. The evaporation and resulting concentration may increase the metal ion concentration and the acid concentration compared to the electrolyte feedstock, such as VMS. In an embodiment, the acid in the second compartment may decrease over time because more H+ ions move through the second membrane 32 than enter through the first membrane 30. This trend may require the addition of an acidic solution to the second compartment to compensate for the reduction in H+ ions. In an embodiment, the acid solution may be characterized by an acid concentration greater than or about 200 g / L, greater than or about 205 g / L, greater than or about 210 g / L, greater than or about 215 g / L, greater than or about 220 g / L, or greater. In addition, at optional operation 230, method 200 may include adding an acidic solution to cathode electrolyte compartment 106, which operation 230 may be performed after operation 225 or simultaneously with operation 225. The acidic solution may be less than or about the amount of the portion of the electrolyte raw material evaporated. In an embodiment, the acidic solution may be provided with water, such as deionized water. In addition, as previously described, method 200 may include adding one or more additives to the cathode electrolyte.

[0052] In order to maintain the acid concentration in the third compartment, the method 200 may include periodically updating at least a portion of the acidic solution in the third compartment. For example, in optional operation 235, the method 200 may include removing a portion of the acidic solution from the third compartment and replacing it with a new acidic solution, and operation 235 may be performed after operation 225 and / or 230 or simultaneously with operation 225 and / or 230. This bleed and feed operation can maintain the acid concentration and pH in the acidic solution in the third compartment 112.

[0053] The method may include forming an anolyte and forming a cathode electrolyte at optional operation 240. The anolyte may be formed in the first compartment, and the cathode electrolyte may be formed in the second compartment. The anolyte may be diluted from an electrolyte raw material, such as a VMS solution. The cathode electrolyte may be concentrated by evaporation, and optionally, an acid may be added during and / or after concentration. The anolyte may be characterized by a metal ion concentration greater than or about 60.0 g / L and an acid concentration less than or about 20.0 g / L. For example, the anolyte may be characterized by a metal concentration greater than or about 62.5 g / L, greater than or about 65.0 g / L, greater than or about 66.0 g / L, greater than or about 67.0 g / L, greater than or about 68.0 g / L, greater than or about 69.5 g / L, greater than or about 70.0 g / L, greater than or about 72.5 g / L, greater than or about 75.0 g / L, greater than or about 77.5 g / L, greater than or about 80.0 g / L, or greater. In addition, the anode electrolyte can be characterized by an acid concentration of less than or about 20.0 g / L, less than or about 15.0 g / L, less than or about 12.5 g / L, less than or about 10.0 g / L, less than or about 9.0 g / L, less than or about 8.0 g / L, less than or about 7.0 g / L, less than or about 6.0 g / L, less than or about 5.0 g / L, less than or about 4.0 g / L, less than or about 3.0 g / L, less than or about 2.0 g / L, less than or about 1.0 g / L, or less. The cathode electrolyte can be characterized by a metal ion concentration greater than or about 50.0 g / L, and can increase to greater than or about 62.5 g / L, greater than or about 65.0 g / L, greater than or about 66.0 g / L, greater than or about 67.0 g / L, greater than or about 68.0 g / L, greater than or about 69.5 g / L, greater than or about 70.0 g / L, greater than or about 72.5 g / L, greater than or about 75.0 g / L, greater than or about 77.5 g / L, greater than or about 80.0 g / L, or greater. The cathode electrolyte may be characterized by an acid concentration of greater than or about 90.0 g / L, such as greater than or about 92.5 g / L, greater than or about 95.0 g / L, greater than or about 97.5 g / L, greater than or about 100.0 g / L, greater than or about 102.5 g / L, greater than or about 105.0 g / L, greater than or about 107.5 g / L, greater than or about 110.0 g / L, greater than or about 112.5 g / L, or greater. In embodiments, operation 240 may include adding a second acidic solution to the cathode electrolyte to increase the acid concentration. In embodiments, the metal ion concentration and acid concentration of the electrolyte raw material, such as VMS, may be selected to determine the metal ion concentration and acid concentration of the anode electrolyte and cathode electrolyte.

[0054] The anolyte and cathode electrolyte can be formed in less than or about 24 hours, such as less than or about 23 hours, less than or about 22 hours, less than or about 21 hours, less than or about 20 hours, or less. In addition, embodiments of the present technology allow the anolyte and cathode electrolyte to be formed simultaneously, further speeding up the preparation of the solution.

[0055] Embodiments of the present technology allow electroplating operations to be performed for extended periods of time with increased metal ion concentrations in the cathode electrolyte. The increased metal ion concentration increases the deposition rate of the metal on the substrate during the electroplating operation, thereby increasing the throughput of substrates of the electroplating system. In an embodiment, the increased metal ion concentration is maintained for extended periods of time by adding a portion of the anode electrolyte of the electroplating system directly to the cathode electrolyte. The metal ion-rich anode electrolyte increases the concentration of metal ions in the cathode electrolyte being consumed by the electroplating operation. The weakly acidic anode electrolyte may also help to reduce the acid concentration of the cathode electrolyte. Adding a portion of the anode electrolyte directly to the cathode electrolyte allows electroplating operations to be performed at metal ion concentrations that may exceed the metal ion concentration in the initial solution containing the metal ions, and these high concentration levels are maintained even when metal ions are being removed from the cathode electrolyte during the electroplating operation.

[0056] In the foregoing description, for the purpose of explanation, many details have been set forth to understand several embodiments of the present technology. However, it will be apparent to one skilled in the art that certain embodiments may be practiced without some of these details or with additional details.

[0057] Where several embodiments have been disclosed, those skilled in the art will appreciate that several modifications, alternative configurations, and equivalents may be used without departing from the spirit of the embodiments. In addition, some well-known processes and components are not described to avoid unnecessary confusion of the present technology. Therefore, the above description should not be taken as limiting the scope of the present technology.

[0058] It should be understood that, unless the context clearly specifies otherwise, in the case of providing a numerical range, the minimum fraction of each intermediate value to the lower limit unit between the upper and lower limits of the range is also explicitly disclosed. Any narrower range between any stated value or unstated intermediate value in the stated range, and any other stated or intermediate value in the range stated here are included. The upper and lower limits of these smaller ranges can be included or excluded independently in the range, and each range that includes any one restriction, both restrictions are not present, or both restrictions are also included in the present technology, but is still subject to any explicitly excluded restrictions in the described range. In the case where the stated range includes one or two restrictions, the range that does not include any one or two of these included restrictions is also included. In the case where multiple values ​​are provided in a list, any range that includes or is based on any of these values ​​is similarly specifically disclosed.

[0059] As used herein and in the appended claims, the singular forms "a", "an", and "the" include plural forms unless the context clearly dictates otherwise. Thus, for example, reference to "a metalion" includes a plurality of such metal ions and reference to "the first compartment" includes one or more compartments and equivalents thereof known to those skilled in the art, and so forth.

[0060] Furthermore, when used in this specification and the claims that follow, the words “comprise(s),” “comprising,” “contain(s),” “containing,” “include(s),” and “including” are intended to refer to the presence of stated features, integers, elements, or operations, but they do not preclude the presence or addition of one or more other features, integers, elements, operations, actions, or groups.

Claims

1. An electroplating method comprising: providing a first portion of an electrolyte raw material to a first compartment of an electrochemical cell, wherein the first portion of the electrolyte raw material is characterized by an initial metal ion concentration and an initial acid concentration; providing a second portion of the electrolyte raw material to a second compartment of the electrochemical cell, wherein the second portion of the electrolyte raw material is characterized by an initial metal ion concentration, and wherein the second compartment and the first compartment are separated by a first separator; providing an acidic solution to a third compartment of the electrochemical cell, wherein the third compartment and the second compartment are separated by a second separator, and wherein the acidic solution is characterized by an initial acid concentration; and A current is applied to an anode of the electrochemical cell, wherein the anode of the electrochemical cell is disposed adjacent to the first compartment and opposite to the first separator.

2. The electroplating method of claim 1, wherein the electrolyte feedstock is characterized by a copper concentration of less than or about 65.0 g / L.

3. The electroplating method of claim 1, wherein the electrolyte feedstock is characterized by an acid concentration greater than or about 90.0 g / L. The electroplating method according to claim 1 , wherein the acidic solution comprises sulfuric acid.

5. The electroplating method according to claim 1, further comprising: When the current is applied to the anode of the electrochemical cell, a portion of the second portion of the electrolyte raw material is vaporized.

6. The electroplating method according to claim 5, further comprising: A second acidic solution is added to the second compartment, wherein the second acidic solution is less than or about the same amount as the evaporated portion of the second portion of the electrolyte raw material.

7. The electroplating method according to claim 1, further comprising: An anolyte is formed from the first portion of the electrolyte feedstock in the first compartment, wherein the anolyte is characterized by: A copper concentration greater than or about 60.0 g / L; and The acid concentration is less than or about 20.0 g / L.

8. The electroplating method according to claim 1, further comprising: forming a cathode electrolyte from the second portion of the electrolyte feedstock in the second compartment, wherein the cathode electrolyte is characterized by: A copper concentration greater than or about 60.0 g / L; and The acid concentration is greater than or about 90.0 g / L.

9. The electroplating method of claim 1, wherein the temperature is maintained at greater than or about 40°C.

10. The electroplating method according to claim 1, further comprising: A portion of the acidic solution is removed from the third compartment and replaced with a new acidic solution, wherein the new acidic solution maintains the acid concentration in the third compartment.

11. The electroplating method according to claim 8, further comprising: A third acidic solution is added to the cathode electrolyte to increase the acid concentration in the cathode electrolyte.

12. The electroplating method according to claim 8, further comprising: One or more chemical additives are added to the cathode electrolyte.

13. An electroplating method comprising: providing a first portion of an electrolyte raw material to a first compartment of an electrochemical cell; providing a second portion of the electrolyte raw material to a second compartment of the electrochemical cell, wherein the second compartment and the first compartment are separated by a first separator; providing an acidic solution to a third compartment of the electrochemical cell, wherein the third compartment and the second compartment are separated by a second separator; Heating the electrochemical cell to a temperature greater than or about 40° C.; applying an electric current to an anode of the electrochemical cell, wherein the anode of the electrochemical cell is disposed adjacent to the first compartment and opposite to the first separator; and An anode electrolyte is formed from the first portion of the electrolyte feedstock and a cathode electrolyte is formed from the second portion of the electrolyte feedstock, wherein the anode electrolyte and the cathode electrolyte are formed simultaneously in the electrochemical cell.

14. The electroplating method according to claim 13, wherein: a portion of the first portion of the electrolyte raw material in the first compartment migrates through the first separator; and The method further includes adding deionized water to the first compartment to compensate for migration of the first portion of the electrolyte raw material through the portion of the first separator.

15. The electroplating method of claim 13, wherein the first portion of the electrolyte feedstock comprises remaining anode electrolyte.

16. The electroplating method of claim 15, wherein forming the anolyte and the catholyte is completed in less than or about 24 hours.

17. An electroplating method comprising: providing a first portion of an electrolyte feedstock to a first compartment of an electrochemical cell, wherein the first compartment comprises a volume greater than or about 200 L; providing a second portion of the electrolyte raw material to a second compartment of the electrochemical cell, wherein the second compartment and the first compartment are separated by a first separator, and wherein the second compartment comprises a volume greater than or about 250 L; providing an acidic solution to a third compartment of the electrochemical cell, wherein the third compartment and the second compartment are separated by a second separator, and wherein the third compartment comprises a capacity of less than or about 50 L; heating the electrochemical cell; applying an electric current to an anode of the electrochemical cell, wherein the anode of the electrochemical cell is disposed adjacent to the first compartment and opposite to the first separator; as well as An anode electrolyte and a cathode electrolyte are formed.

18. The electroplating method of claim 17, wherein heating the electrochemical cell comprises heating the electrochemical cell to a temperature greater than or about 40°C.

19. The electroplating method of claim 17, wherein the anolyte and the catholyte are formed simultaneously in the electrochemical cell.

20. The electroplating method according to claim 17, further comprising: Portions of the acidic solution in the third compartment are replaced to maintain an acid concentration in the acidic solution.

21. The electroplating method according to claim 17, wherein the first diaphragm and the second diaphragm comprise different diaphragm materials.

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