TW202442944A - Methods of reducing or eliminating deposits in an electroplating system - Google Patents

Abstract

The present technology includes methods for reducing the formation of insoluble deposits in a plating system or a surface thereof. The methods include reducing a volume of a plating solution having a first pH in a plating bath from a first volume to a second volume, adding a replenishment agent to the plating solution to increase the volume of the plating solution from the second volume to the first volume. The replenishment agent is characterized by a second pH, where the second pH varies from the first pH by less than or about 5.

Description

Method for reducing or eliminating deposits in electroplating systems

The present technology relates to reducing or eliminating deposits or precipitates before, during and after electrochemical plating. More specifically, the present technology relates to methods of using a supplement having a preset pH value to reduce insoluble deposits, such as plate-up or precipitates, on various surfaces of a plating system or in a plating bath.

Integrated circuits are made possible by processes that create multiple layers of complex patterned materials on multiple substrate surfaces. After formation, etching, and other processing on the substrate, metal or other conductive material is typically deposited or formed to provide electrical connections between the multiple components. Because this metallization may occur after many manufacturing operations, problems during metallization can result in expensive scrap substrates or wafers.

The metal layer is typically applied to the wafer by electrochemical plating in a plating chamber, such as an electroplating chamber. A typical plating chamber includes a container for holding an electrolyte or plating solution, one or more anodes in the container and in contact with the plating solution, and a head with a contact ring having a plurality of electrical contact fingers that contact the substrate. The conductive surface of the workpiece is immersed in the plating solution (such as a liquid electrolyte bath), and the electrical contact causes the metal ions in the plating solution to plate on the substrate to form a metal layer or film. Multiple plating processors and other types of processors are typically provided within a housing to form a plating system, such as an electroplating system.

The formation of insoluble deposits that plate upward on the electrical contacts on the plating bath components and/or contact rings requires frequent cleaning and/or deplating maintenance. In addition, the buildup of insoluble deposits in the plating bath or on the plating bath components often reaches such an extent that the plating bath itself must be replaced.

Thus, there is a need for methods of avoiding insoluble deposits in the plating bath or on the surface of the plating bath and on components. The present technology can meet these needs and other needs.

Various embodiments of the present technology include methods of reducing deposit formation in a plating bath, or insoluble deposit formation in or on a surface of a plating system. Various embodiments of the methods include reducing the volume of a plating solution having a first pH value in a plating bath from the first volume to a second volume. Various embodiments include adding a replenishment agent to the plating solution to increase the volume of the plating solution from the second volume to the first volume, wherein the replenishment agent has a second pH value that differs from the first pH value by less than or about 5.

In various embodiments, the first pH of the plating solution changes by less than or about 3 after the addition of the supplement. In other embodiments, the plating solution further comprises metal ions, organometallic particles, organic particles, or a combination thereof. In more embodiments, less than about 10 wt.% of the metal ions, organometallic particles, organic particles, or a combination thereof precipitates from the plating solution after the addition of the supplement. In other embodiments, reducing the volume comprises evaporating a portion of the plating solution. Various embodiments comprise the plating solution having a first electrolyte concentration and a second electrolyte concentration after the addition of the supplement, wherein the first electrolyte concentration differs from the second electrolyte concentration by 10 wt.% or less.

Additionally or alternatively, various embodiments include a first pH value of about 0 to about 5, and a second pH value of about 0 to about 5. Further embodiments include a first pH value of about 8 to about 12, and a second pH value of about 8 to about 12. In various embodiments, the second pH value differs from the first pH value by less than or about 1.5. In more embodiments, the second pH value differs from the first pH value by less than or about 3.

In various embodiments, the supplement is an inorganic acid, carbonic acid, cathode water, anode water, or a combination thereof. Various embodiments include a pH value of the supplement less than 3.

Various embodiments of the present technology include methods of reducing the formation of insoluble deposits in or on a surface of an electroplating system. Various embodiments include reducing the volume of a plating solution having a first pH in a plating bath. Various embodiments include adjusting a supplement to have a second pH, wherein the second pH differs from the first pH by less than 3 or about 3. In various embodiments, the supplement includes carbonic acid, electrolyzed water, or a combination thereof. In various embodiments, the supplement is substantially free of an inorganic acid.

Various embodiments of the present technology include methods for reducing the formation of insoluble deposits in or on a surface of a plating system. Various embodiments include a plating system, the plating system including a plating bath containing a plating solution, a head including a seal, a substrate coupled to the seal, and a plating bath supply. Various embodiments include moving the head from a first position to a second position, wherein the seal and the substrate are disposed in the plating solution in the second position. Various embodiments include exposing the substrate to one or more insoluble ions. Various embodiments include adding a supplemental agent to the plating solution. In various embodiments, the supplemental agent has a second pH value, wherein the second pH value differs from the first pH value by less than or about 5.

In various embodiments, the electroplating system also includes an electroplating solution conditioning system. In more embodiments, the method includes adjusting the supplement to have a second pH value. In other embodiments, the conditioning includes selecting an acid, adjusting the acid concentration, adding an acidifying agent, adding an alkalization agent, or a combination thereof.

This technology can provide many benefits over conventional techniques. For example, various embodiments of the technology reduce or even eliminate up-plating on surfaces of or components in a plating system. In addition, the technology can use supplements that do not change the existing plating bath solute concentration. Thus, the technology can provide a method to reduce or eliminate insoluble buildup to significantly extend the life of the plating system. These and other embodiments, as well as their many benefits and features, are described in more detail in conjunction with the following description and accompanying drawings.

Existing electroplating systems show loss of plating liquid volume, for example due to evaporation, overflow, etc. Conventional systems use deionized water to maintain the plating liquid volume. However, deionized water problematically causes insoluble contaminants to form in the plating bath, such as organometallics, metals, etc., which deposit, plate upward, or form scale in the plating bath or on the bath surfaces and components, including seals that separate the components from input and output lines and substrate support heads and that maintain the plating liquid away from electrical contacts. The deposits contain insoluble solids and/or their precursors, which can be deposited as scale on processing equipment. For example, up-plating can be caused by various metals and organic precursors in the plating solution. Up-plating on system components can also problematically result in the formation of a conductive path between the component and the contact, which can cause more contact plating than the required substrate plating and lead to seal and contact failure.

Traditional methods of removing insoluble deposits, such as plating-up, focus on removal chemicals or physical mechanisms designed to remove insoluble deposits formed on the surfaces of the plating system and components thereon. For example, a physical mechanism may include the use of a brush, polymer pad, or similar device to physically contact the system or its components to remove some of the contaminants. Alternatively, the removal chemical may include a cleaning agent such as nitric acid, other acids, sodium hydroxide, potassium hydroxide, or other strong bases. Unfortunately, such physical and chemical traditional mechanisms require the removal or disassembly of the plating bath, or the removal of the plating solution, and generally fail to remove all of the plating-up present. Such inefficient removal results in frequent replacement, as any remaining insoluble deposits increase the rate and amount of future deposits when reused.

The present technology has found that the use of a supplement with a preset pH value can reduce or even avoid the formation of insoluble deposits, thereby eliminating the need for extensive cleaning treatments. The present technology has found that a large difference between the pH of the plating bath and the pH of the supplement can increase the deposition of insoluble materials on the components of the plating system or on its surface. That is, due to the pH change caused by the addition of the supplement, organic particles, metal particles and ions, and organometallic particles that were dissolved in the pH of the plating solution before dilution are forced to precipitate out of solution and attach to any available surface. When it occurs a single time, the insoluble deposits are almost negligible. However, on surfaces that are repeatedly cycled with a low plating bath volume followed by a supplement with a higher or lower pH, each cycle can produce an insoluble deposit that accumulates as the cycles proceed. The final deposit can form a conductive or semiconductive film that serves as a precursor for upward plating. Once a conductive path is formed between the electron source (e.g., power supply) and the precursor film, upward plating occurs. Thus, the present technology has discovered that even in embodiments without cleaning, careful control of the pH of the supplement can reduce or eliminate upward plating by avoiding initial precipitation and deposition of insoluble materials.

The present disclosure notes that avoiding deposits or up-plating can beneficially maintain the life of the plating equipment including contacts or sealing rings while eliminating scheduled downtime for cleaning. For example, providing a supplement having a preset pH value that differs from the pH of the plating solution by less than 5 or about 5 can eliminate the need for cleaning and/or deplating maintenance on the sealing rings and/or electrical contacts on the contact rings. By avoiding or reducing the need to remove insoluble deposits by avoiding the formation of deposits, the throughput or efficiency of use of the plating system is increased because the plating system does not need to be idle during the cleaning step. The present disclosure notes that providing a supplement having a pH similar to the pH of the plating solution or electrolyte can avoid or reduce the deposition of contaminants or problematic materials that accumulate on surfaces within the plating system or promote the formation of insoluble deposits on surfaces within the plating system because the contaminants or problematic materials remain soluble rather than precipitating out of solution. For example, since the insoluble material remains a solute or soluble material in solution, the insoluble material can be easily removed from the equipment or processing system by filtration or separation.

For example, in various embodiments, less than 20 wt.% or about 20 wt.% of the metal ions, metal particles, organometallic particles, organic particles, or combinations thereof are precipitated from the plating solution after adding the supplements discussed herein, based on the weight of the metal ions, metal particles, organometallic particles, organic particles, or combinations thereof present in the plating solution before the supplements are added, such as less than 15 wt.% or about 15 wt.%, such as less than 10 wt.% or about 10 wt.%, such as less than 7.5 wt.% or about 7.5 wt.%, such as less than 5 wt.% or about 5 wt.%, such as less than 2.5 wt.% or about 2.5 wt.%, based on the weight of the metal ions, metal particles, organometallic particles, organic particles, or combinations thereof present in the plating solution before the supplements are added, during each rinse/replenishment cycle or during the life of the plating bath. wt.%, such as less than 1 wt.% or about 1 wt.%, or any range or value therebetween.

However, FIG. 1 is a schematic perspective view of a plating system 100 that can perform a variety of plating methods according to various embodiments of the present technology. The plating system 100 can be operated to perform both plating operations and electroless plating operations. In a plating operation, the plating system 100 delivers an electric current to a substrate so that ions in a plating bath that contact the substrate can be reduced and plated on the substrate. In a electroless plating operation, the plating system 100 does not deliver an electric current to the substrate. Instead, plating relies on the spontaneous reduction of ions in a plating bath when they contact a substrate surface, which comprises a standard electrode potential (standard electrode potential; ) is lower than the ions in the plating bath. Plating system 100 illustrates an exemplary plating system that includes a system head 110 and a bowl 115. During a plating operation, a substrate can be clamped to the system head 110, inverted, and extended into the bowl 115 for plating operations. The plating system 100 can include a head lift 120 that can be configured to raise and rotate the system head 110, or otherwise position the head in the system, including tilting operations. The head and bowl can be attached to a platform plate 125 or other structure that can be part of a larger system that includes multiple plating systems 100 that can share electrolytes and other materials. The rotor may rotate the substrate held in the head within the bowl or outside the bowl in different operations. The rotor may include a contact ring that provides conductive contact with the substrate. A seal 130, discussed further below, may be connected to the head. The seal 130 may include a chucked wafer to be processed.

FIG. 1 shows a plating system 100 that may include multiple components to be cleaned directly on the platform. In various embodiments, the plating system 100 further includes an in situ flushing system 135 for component cleaning. In other embodiments (not shown), the plating system may be configured to have a platform on which the head may be moved to an additional module for cleaning seals or other components.

FIG. 2 is a partial cross-sectional view of a plating chamber including a plating apparatus 200 according to some embodiments of the present technology. The plating apparatus 200 can be incorporated into a plating system, including the plating system 100 described above. FIG. 2 shows a plating bath 205 and a head 210 of the plating system, the plating bath 205 containing a plating solution 207 (e.g., a liquid electrolyte bath), and a substrate 215 coupled to the head. An inlet supply 212 (more clearly shown in FIG. 3, 312) can provide a dielectric and a source of metal ions to be deposited on the surface of the substrate, and can also provide a supplementary agent as discussed herein. The metal to be plated on the substrate is present in the plating solution in the form of metal ions to be deposited on the substrate. In some embodiments, metal ions are deposited under process conditions where the metal ions are preferentially deposited in the recessed features relative to the surrounding field surface. In some embodiments, the head 210 can be moved to a position where the wafer substrate 215 contacts the plating solution 207 (e.g., a liquid electrolyte bath) in the plating bath 205. The plating apparatus can also include a plating bath return line 214.

In the illustrated embodiment, the substrate is coupled to a seal 216 that is bonded to the header 210. A rinsing frame 220 may be coupled above the plating bath 205 and may be configured to receive the header 210 into a container during plating. The rinsing frame 220 may include a rim 225 that extends annularly over the upper surface of the plating bath 205. A rinsing channel 227 may be defined between the rim 225 and the upper surface of the plating bath 205. For example, the rim 225 may include a sidewall 230 having an inclined profile on the inside. As described above, rinsing fluid ejected from the substrate may contact the sidewall 230 and may be received by a plenum 235 that extends around the edge to collect rinsing fluid from the electroplating apparatus 200.

In some embodiments, the plating apparatus 200 may additionally include one or more cleaning elements. The cleaning elements may include one or more nozzles for delivering fluid to or toward the substrate 215 or the head 210. FIG. 2 illustrates one of a variety of embodiments in which improved rinse assemblies may be used to protect the plating bath and substrate during the rinse operation. In other embodiments, the side cleaning nozzles 250 may extend through the edge 225 of the rinse frame 220 and be directed to rinse the seal 216 and various aspects of the substrate 215.

FIG. 3 is a schematic diagram of a plating solution conditioning system 300. The plating solution conditioning system 300 provides electrolyte and components (constituents) generated during the plating process, referred to herein as components, and supplementary agents to the plating system for the plating process. The plating solution conditioning system 300 generally includes a supply tank 302, a conditioning module 303, a filter module 305, a chemical analyzer module 316, and a plating bath waste treatment system 322, and the plating bath waste treatment system 322 is connected to the chemical analyzer module 316 via an outlet pipe 321. One or more controllers 310, 311 and 319 control the composition and ingredients of the electrolyte in the supply tank 302 and control the operation of the plating solution conditioning system 300. Preferably, the multiple controllers can operate independently but are integrated into the control system 318 of the plating system 100.

The supply tank 302 provides a storage tank for electrolyte and components and includes a supply pipe 312 connected to each of a plurality of electroplating process tanks through one or more fluid pumps 308 and valves 307. A heat exchanger 324 or heater/cooler configured to be thermally connected to the supply tank 302 controls the temperature of the electrolyte and components stored in the supply tank 302. The heat exchanger 324 is connected to the controller 310 and is operated by the controller 310.

The regulating module 303 is connected to the supply tank 302 by a supply pipe and includes a plurality of source tanks 306, 330 or feed bottles, a plurality of valves 309, 307, and a controller 311. The source tank 306 contains the chemicals required to form the electrolyte and components, and typically includes a deionized water source tank and a copper sulfate ( _CuSO4 ) source tank to form the electrolyte. The source tank 330 contains a supplementary agent and can therefore be referred to as a supplementary agent tank 330. The supplementary agent tank 330 of the regulating module 303 is preferably regulated by a valve 331 and controlled by the controller 311. Other source tanks 306 may contain sulfuric acid ( _{H2SO4 )} , hydrogen chloride (HCl) and various additives, such as ethylene glycol or carbon dioxide.

Valves 309 and 331 associated with each source tank 306, 330 regulate the flow of chemicals to the supply tank 302 and can be any of a variety of commercially available valves, such as butterfly valves, throttle valves, etc. Activation of valves 309 and 331 is achieved by controller 311, which is preferably connected to control system 318 to receive signals from control system 318. Filter module 305 includes a plurality of filter tanks 304. Return pipes 314 are connected between each processing tank and one or more filter tanks 304. The filter tanks 304 remove unwanted contents from the used plating solution before the plating solution is returned to the supply tank 302 for reuse.

The supply tank 302 is also connected to the filter tank 304 to facilitate the recirculation and filtering of the dielectric and components in the supply tank 302. By recirculating the plating solution from the supply tank 302 through the filter tank 304, the unwanted contents of the plating solution are continuously removed by the filter layer 304 to maintain a consistent purity. In addition, the recirculation of the plating solution between the supply layer 302 and the filter module 305 allows the various chemical substances in the plating solution to be thoroughly mixed.

The plating solution conditioning system 300 also includes a chemical analyzer module 316 that provides real-time chemical analysis of the chemical composition of the electrolyte and components. The analyzer module 316 is fluidly coupled to the supply tank 302 through a sample tube 313 and is fluidly coupled to the plating bath waste disposal system 322 through an outlet tube 321. The analyzer module 316 typically includes at least one analyzer and a controller for operating the analyzer.

The number of analyzers required for a particular process tool depends on the composition of the plating solution. For example, while a first analyzer may be used to monitor the concentration of organic species, a second analyzer may be required to determine the pH of the plating solution and/or the supplement. Additional analyzers may be used to monitor specific components to be added to the plating solution, preferably components whose concentrations may affect the pH of the supplement.

In the specific embodiment shown in FIG. 3 , the chemical analyzer module 316 includes an automatic titration analyzer 315 and a pH measurement system 317. Both analyzers can be purchased from various suppliers. The automatic titration analyzer 315 measures the concentration of inorganic substances, such as cupric chloride and acids used for copper deposition. The pH measurement system 317 measures the pH of the plating solution 207 and the supplementary agent returned from the treatment tank to the supply tank 302. The analyzer module shown in FIG. 3 is exemplary only. In another embodiment, each analyzer can be coupled to the supply tank by a separate supply tube and can be operated by a separate controller. The controller 319 sends a command signal to operate the automatic titration analyzer 315 and the pH value measurement system 317 to generate data.

Information from the automatic titration analyzer 315 and the pH determination system 317 is then transmitted to the control system 318. The control system 318 processes the information and transmits a signal containing user-defined chemical dosage parameters to the regulation controller 311. The received information is used to operate one or more valves 309 and 331 to provide real-time adjustment of the source chemical regulation ratio, thereby maintaining the desired and preferably constant chemical composition of the electrolyte and components throughout the electroplating process. The waste from the analyzer module then flows through the outlet pipe 321 to the electroplating bath waste treatment system 322.

However, as previously described, the addition of the supplemental agent may also be initiated by the control system 318 via the controller 311 during the deposition process, either continuously or periodically. Once in the supply tank 302, the pH of the supplemental agent is analyzed. The pH is then adjusted to be less than 5 or about 5 different from the pH of the plating solution, such as less than 4.5 or about 4.5, such as less than 4.25 or about 4.25, such as less than 4 or about 4, such as less than 3.75 or about 3.75, such as less than 3.5 or about 3.5, such as less than 3.25 or about 3.25, such as less than 3 or about 3, such as less than 2.75 or about 2.75, such as less than 2.5 or about 2.5, such as less than 2.25 or about 2.25, such as less than 2 or about 2, such as less than 1.75 or about 1.75, such as less than 1.5 or about 1.5, such as less than 1.25 or about 1.25, such as less than 1 or about 1, such as less than 0.75 or about 0.75, such as less than 0.5 or about 0.5, such as less than 0.25 or about 0.25, or any range or value therebetween. Thus, in various embodiments, the pH of the plating solution and the pH of the supplement may be substantially the same.

In other words, in many embodiments, the pH of the supplement can be selected so that the pH of the plating solution in a subsequent supplement varies by less than 20% or about 20%, such as less than 15% or about 15%, such as less than 12.5% or about 12.5%, such as less than 10% or about 10%, such as less than 7.5% or about 7.5%, such as less than 5% or about 5%, such as less than 2.5% or about 2.5%, such as less than 1% or about 1%, or any range or value therebetween. For example, in many embodiments, in subsequent replenishments, the pH of the plating solution changes by less than 4 or about 4, such as less than 3.5 or about 3.5, such as less than 3 or about 3, such as less than 2.75 or about 2.75, such as less than 2.5 or about 2.5, such as less than 2.25 or about 2.25, such as less than 2 or about 2, such as less than 1.75 or about 1.75, such as less than 1.5 or about 1.5, such as less than 1.25 or about 1.25, such as less than 1 or about 1, such as less than 0.75 or about 0.75, such as less than 0.5 or about 0.5, such as less than 0.25 or about 0.25, or any range or value therebetween.

In various embodiments, the pH of the plating solution may differ from the pH of the supplement by about 2 or less, such as about 1.5 or less, such as about 1 or less, such as about 0.5 or less, such as about 0.2 or less, or any range or value therebetween. For example, in various embodiments, when the pH of the plating solution is about 0 to about 5, such as about 0.5 to about 4.5, such as about 1 to about 4, or any range or value therebetween, the pH of the supplement is also about 0 to about 5, such as about 0.5 to about 4.5, such as about 1 to about 4, or any range or value therebetween. Additionally or alternatively, when the first pH value is about 8 to about 12, such as about 8 to about 11, such as about 8.5 to about 10, or any range or value therebetween, the second pH value is about 8 to about 12, such as about 8 to about 11, such as about 8.5 to about 10, or any range or value therebetween.

That is, as previously described, by using a supplement with a preselected pH value, rapid changes in the pH of the plating solution can be avoided and insoluble materials can be kept in solution. The pH of the plating solution can be measured according to known techniques, such as using a pH meter in a solution at 20 degrees Celsius to obtain the pH of the plating solution (a first pH value), and the pH of the supplement can be predetermined or calibrated based on the above values as described to obtain a second pH value, which can be the same or different from the first pH value. In many embodiments, the pH meter is calibrated by methods known in the art. In some embodiments, the pH value of the plating solution and/or the supplement may be less than 6 or approximately 6, for example, less than 5 or approximately 5, for example, less than 4.5 or approximately 4.5, for example, less than 4 or approximately 4, for example, less than 3.5 or approximately 3.5, for example, less than 3 or approximately 3, for example, less than 2.5 or approximately 2.5, for example, less than 2 or approximately 2, for example, less than 1.5 or approximately 1.5, for example, less than 1 or approximately 1, or any range or value therebetween. Additionally or alternatively, in various embodiments, the pH of the plating solution and/or supplement may be greater than 7 or approximately 7, for example greater than 8 or approximately 8, for example greater than 8.5 or approximately 8.5, for example greater than 9 or approximately 9, for example greater than 9.5 or approximately 9.5, for example greater than 10 or approximately 10, for example greater than 10.5 or approximately 10.5, or any range or value therebetween.

In various embodiments, the pH of the plating solution, the supplement, or a combination thereof may be selected based on the precursor particles in the solution. That is, as is known in the art, some plating materials, such as tin-silver (SnAg), have an increased likelihood of up-plating of insoluble particles and may therefore require a very low pH (e.g., less than or about 3) in the plating solution, or the supplement, or both to increase solubility and avoid insoluble deposits. However, it will be appreciated by those skilled in the art that non-limiting metals (or their ions) that may be included in the plating solution include copper, tin, gold, nickel, silver, palladium, platinum and rhodium, and alloys such as precious metal alloys, tin-copper alloys, tin-silver alloys, tin-silver-copper alloys, tin-bismuth alloys, permalloy and other nickel alloys, lead-tin alloys and other lead-free alloys, and may be used in a plating system having any one or more of the above-mentioned pH values or ranges.

In addition, in various embodiments, the supplement may contain a supplement in a solvent. In various embodiments, the solvent may be the same as the solvent contained in the plating solution electrolyte, for example, in some embodiments, it may be water (deionized water). Selecting the pH value of the supplement may include selecting the type of supplement. In various embodiments, the supplement is an inorganic acid, such as an acid derived from an inorganic compound. Non-limiting examples of suitable inorganic acids include hydrogen bromide (BrH), hydrogen iodide (HI), hydrochloric acid (HCl), nitric acid (HNO ₃ ), nitrous acid (HNO ₂ ), phosphoric acid (H ₃ PO ₄ ), sulfuric acid (H ₂ SO ₄ ), boric acid (H ₃ BO ₃ ), hydrofluoric acid (HF), hydrobromic acid (HBr), perchloric acid (HClO ₄ ), hydroiodic acid (HI), and combinations thereof. In various embodiments, organic acids such as sulfonic acids, such as methanesulfonic acid (MSA), are suitable supplemental agents according to the present disclosure. In various embodiments, the organic acid provides pH control as described herein, but can also act as a chelating agent sufficient to bond with species in solution that, if not chelated, might promote upward electroplating film formation. In some embodiments, the methanesulfonic acid may comprise 1 M methanesulfonic acid and may be diluted with water in a ratio of 50: 1. In some embodiments, methanesulfonic acid suitable for use herein comprises methanesulfonic acid having a molar concentration of 0.02 M to about 1 M, such as about 0.03 M to about 0.75 M, such as about 0.4 M to about 0.5 M, or any range or value therebetween, and having a pH between 1 and 6, such as between 2 and 5, such as between 2.5 and 4.5.

In various embodiments, the supplement comprises only methanesulfonic acid, or a combination of methanesulfonic acid and one or more pH adjusters. For example, methanesulfonic acid (pH of about 2 and a concentration of about 20 g/L of methanesulfonic acid in water) can provide a pH sufficient to avoid or eliminate the formation of a precursor layer and/or subsequent upward electroplating. In one embodiment, methanesulfonic acid is a suitable rinse agent for use in the present disclosure, wherein the methanesulfonic acid has a concentration of at least 3.6 g/L and the pH of its solution is about 3.

However, in various embodiments, the present disclosure has found that by using a mineral acid in the extender, the total concentration of the mineral acid in the electroplating bath may increase with time. Thus, in various embodiments, the extender is an acidic solution comprising carbonic acid (H ₂ CO ₃ ). In various embodiments, the carbonic acid extender is provided by dissolving carbon dioxide in water and bringing it to a desired pH under pressure. In various embodiments, the carbon dioxide may also be injected directly into the water to form carbonic acid, or the carbon dioxide may be pressurized on one side of a permeable membrane and the water on the other side of the membrane. Such systems are commercially available and are generally referred to as gas contactors. The gas diffuses through the barrier and dissolves in the water, thereby forming carbonic acid. In various embodiments, carbonic acid is provided in sufficient amounts and under conditions suitable to avoid the formation of insoluble precipitates.

Additionally or alternatively, in various embodiments, the supplement is electrolyzed water, such as cathodic water having a pH value according to one or more of the aforementioned ranges. By using cathodic water as a supplement, the components of the plating solution and/or plating bath remain in solution and do not form deposits in the plating bath or deposits on the surface, which would form the upward plating precursor film and the final upward plating. In various embodiments, for example, alkaline plating solutions or baths, anodic water can be used in a similar manner.

Thus, in many embodiments, the supplement can be an inorganic acid, carbonic acid, electrolyzed water (including cathodic and/or anodic water), or a combination thereof. In more embodiments, the supplement can be methanesulfonic acid, carbonic acid, electrolyzed water, or a combination thereof.

Furthermore, in various embodiments, the plating solution contains a first electrolyte concentration before the addition of the supplemental agent, and the plating solution contains a second electrolyte concentration after the addition. In various embodiments, the first electrolyte concentration differs from the second electrolyte concentration by less than or about 10 wt.%, such as less than or about 9 wt.%, such as less than or about 8 wt.%, such as less than or about 7 wt.%, such as less than or about 6 wt.%, such as less than or about 5 wt.%, such as less than or about 4 wt.%, such as less than or about 3 wt.%, such as less than or about 2 wt.%, such as less than or about 1 wt.%, or any range or value therebetween, based on the weight of the electrolyte in the plating solution. In some embodiments, the supplement may therefore be substantially free of inorganic acid to avoid an increase in electrolyte concentration.

However, in many embodiments, a pH adjuster may also be included to give the supplement a preselected pH value. In many embodiments, the pH adjuster may be provided in any amount necessary to obtain the desired pH value in the final composition of the supplement. Acidic pH adjusters may be organic acids (including amino acids) and inorganic acids. Non-limiting examples of acidic pH adjusters include acetic acid, citric acid, fumaric acid, glutamic acid, glycolic acid, hydrochloric acid, lactic acid, nitric acid, phosphoric acid, sodium bisulfate, sulfuric acid, etc., and combinations thereof. In many embodiments, all organic acids may be used as pH adjusters. Non-limiting examples of alkaline pH adjusters include alkaline metal hydroxides (such as sodium hydroxide and potassium hydroxide), ammonium hydroxide, organic bases, and alkaline metal salts of inorganic acids (such as sodium borate (borax), sodium phosphate, sodium pyrophosphate, etc., and mixtures thereof).

As can be seen from the above, adjusting the supplement may include one or more operation steps 410, which will be described in more detail with reference to FIG. 4. For example, in various embodiments, adjusting the supplement includes changing the native pH of the supplement to a second pH. In various embodiments, as described above, the adjustment may include selecting a supplement with a desired pH. In this embodiment, the native pH may be substantially equal to the second pH. Additionally or alternatively, the adjustment may include changing the acid concentration in the solution of the supplement, adding a pH adjuster (e.g., an acidulant or an alkalizer), or a combination thereof.

However, after the supplement has been adjusted to the desired pH, the supplement may be delivered to the plating bath 205 to replace any lost plating liquid volume. In various embodiments, the supplement may be supplied continuously, or the supplement may be added after one or more plating cycles. Additionally or alternatively, based on the volume of the plating bath solution, the supplemental agent can be added to the plating bath 205 when the plating bath 205 shows a decrease in the volume of the plating solution by greater than or about 1 vol%, such as a decrease in volume by greater than or about 2.5 vol%, such as a decrease in volume by greater than or about 5 vol%, such as a decrease in volume by greater than or about 7.5 vol%, such as a decrease in volume by greater than or about 10 vol%, or any range or value therebetween. For example, in various embodiments, the plating bath can have an operating volume, and the supplemental agent is added to the plating bath when the fluid drops below the operating level until the operating level is reached again.

Although the above-described embodiments use real-time monitoring and adjustment of supplements, various alternatives may be employed in accordance with the techniques described herein. For example, the adjustment module 303 may be manually controlled by an operator observing the output values provided by the chemical analyzer module 316. For example, the system software may allow for an automatic real-time adjustment mode and an operator (manual) mode. In addition, although FIG. 3 shows multiple controllers, a single controller may be used to operate various components of the system, such as the chemical analyzer module 316, the adjustment module 303, and the heat exchanger 324. Other embodiments will be apparent to those of ordinary skill in the art.

However, it should be understood that in various embodiments, methods according to the present disclosure include a non-transitory computer readable medium having instructions stored thereon that, when executed, may result in a method for reducing or eliminating the formation of conductive deposits on a surface in an electroplating system. For example, in various embodiments, the non-transitory computer readable medium may perform any one or more of the steps of the method, such as performing a pH measurement, comparing pH values, adjusting the pH of a supplement, and/or replenishing a plating bath.

The plating solution conditioning system 300 also includes a waste drain 320 that connects to a plating bath waste disposal system 322 for safe disposal of spent electrolytes, components, chemicals, and other fluids used in the plating system. Preferably, the plating cell includes a direct piping connection to the waste drain 320 or the plating bath waste disposal system 322 to drain the plating cell without returning the plating solution through the plating solution conditioning system 300. The plating solution conditioning system 300 also preferably includes a bleed off connection to discharge excess electrolyte and components to the waste drain 320.

Although not shown in FIG. 3 , the plating solution conditioning system 300 may include many other components. For example, the plating solution conditioning system 300 preferably also includes one or more additional tanks to store chemicals for the substrate cleaning system. Double-contained piping for hazardous material connections may also be used to safely transport chemicals throughout the system. Optionally, the plating solution conditioning system 300 includes connections to additional or external processing systems to provide additional supplies to the plating system.

Embodiments of the above-described systems and chambers may be present in a plating chamber that exhibits reduced or eliminated deposits or up-plating as discussed herein. FIG. 4 illustrates exemplary operating steps in a method 400 for replenishing a plating bath according to embodiments of the present technology. The method 400 may also include one or more operating steps prior to the start of the method, including filling, plating, solute adjustment, or any other operating steps that may be performed prior to the operating steps. The method may further include a number of optional operating steps that may or may not be specifically related to some embodiments of the method according to the present technology. For example, many operating steps are described to enable the method to be performed to have a broader scope, but these operating steps are not essential to the present technology or may be performed in alternative methods, as will be discussed in more detail below.

Method 400 may include a plurality of operating steps as described above with respect to FIGS. 1 to 3 to reduce the formation of insoluble deposits in or on a semiconductor plating system during plating. For example, method 400 includes operating step 402, which includes providing a plating system 100. In optional operating step 404, as described above, the plating system 100 may include a movable head that can be moved from a first position to a second position to configure the substrate 215 and/or the seal 130 to contact the plating solution 207. After the substrate 215 and/or the seal 130 are configured to contact the plating solution 207, the method may include optional operating step 406 of the substrate 215, as described above.

At operation 408, the volume of the plating solution may decrease. In various embodiments, the volume decrease may be due to evaporation, overflow, transfer, etc. However, in various embodiments, the volume of the plating solution decreases from a first volume to a second volume.

Operation 410 includes the step of optionally adjusting the supplement. As described above, in some embodiments, the supplement may already have a suitable pH and may not require adjustment. However, a supplement may be provided at operation 410 whose pH differs from the pH of the plating solution by less than or about 40%. As described above, the supplement may have a desired pH natively, or may be adjusted at operation 410 to include one or more additional pH adjusters.

However, in various embodiments, the method includes, as shown in operation 412, supplementing a plating bath solution having a first pH value (measured pH value) with a supplementer to a volume greater than a second volume, which in various embodiments may be equal to the first volume. In addition, as described above, it should be understood that method 400 does not require the removal of any components from the plating bath or the disassembly of the plating bath itself. Instead, by carefully adjusting the composition of the supplementer, the plating bath precipitate or insoluble material that is plated upward can be maintained in solution and can be removed using any of the filtration processes discussed in connection with FIG. 3. Thus, the present technology can avoid the occurrence of upward plating without requiring downtime of the plating bath, and can eliminate the need for disruptive cleaning processes. In addition, the present technique has discovered that the use of a supplement as discussed herein can avoid the initial precipitation of insoluble particles or ions caused by rapid pH changes when adding a diluent having a completely different pH. Thus, the formation of an initial layer of plating bath deposits or insoluble materials, and the resulting upward plating, can be greatly reduced or completely avoided. This effect is particularly evident in the portion of the plating bath 205 adjacent to the inlet supply 212, such as any seals, valves, or components adjacent to the inlet supply 212 (not shown), and any seals or locations that are particularly susceptible to insoluble deposits.

Additionally, it should be understood that the initial volume may also be understood as the first volume. Thus, in some aspects, operation step 412 may occur when a second volume less than the first volume is detected in the electroplating system 100. The reduction in the volume of the plating solution may be based on any one or more of the values or ranges discussed above.

In the foregoing description, for purposes of illustration, many details have been set forth to provide an understanding of various embodiments of the present technology. However, it will be apparent to one of ordinary skill in the art that certain embodiments may be practiced without some of these details or with additional details. For example, other plating baths or plating apparatus that benefit from the techniques of avoiding upward plating or avoiding residues may also be used with the present technology.

While several embodiments have been disclosed, those skilled in the art will appreciate that various variations, alternative configurations, and equivalents may be used without departing from the spirit of the embodiments. In addition, some known processes and components are not described herein to avoid unnecessary confusion of the present technology. Therefore, the above description should not be regarded as limiting the scope of the present technology.

When providing a numerical range, it should be understood that, unless otherwise clearly indicated herein, every intermediate value between the upper and lower limits of the range is also explicitly disclosed to the smallest fraction of the lower limit unit. Any narrower range between the values or any unstated intermediate values in the range, as well as any other stated or intermediate values in the range, are included. The upper and lower limits of these smaller ranges may be independently included in the range or excluded from the range, and any range in which either limit is included in the smaller range, both limits are not included in the smaller range, or both limits are included in the smaller range is included in the present technology, but is still subject to any explicitly excluded limits in the range. When the stated range includes one or both of the limits, ranges excluding either or both of those limits are also included. When a list provides multiple values, any ranges including or based on any of those values are similarly explicitly disclosed.

As used herein and in the appended claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Thus, for example, reference to "a supplement" includes a plurality of such supplements and reference to "the volume" includes one or more volumes and equivalents thereof known to those skilled in the art, and so forth.

Furthermore, the terms "comprise", "include" and "include" in this specification and the following patent application are intended to clearly describe the described features, integers, components or operations, but do not exclude the existence or addition of one or more other features, integers, components, operations, actions or groups.

100: Plating system 110: System head 115: Bowl 120: Head lift 125: Platform plate 130: Seal 135: Flushing system 200: Plating equipment 205: Plating bath 207: Plating solution 210: Head 212: Inlet supply 214: Plating bath return pipe 215: Substrate 216: Seal 220: Flushing frame 225: Edge 227: Flushing channel 230: Side wall 235: Air chamber 250: Side cleaning nozzle 300: Plating solution regulation system 302: Supply tank 303: Regulating module 304: Filter tank 305: Filter module 306,330: Source tank 307,309,331: Valve 308: Fluid pump 312: Supply pipe 313: Sample pipe 314: Reflux pipe 315: Automatic titration analyzer 316: Chemical analyzer module 317: pH value determination system 318: Control system 310,311,319: Controller 320: Waste drain pipe 321: Outlet pipe 322: Electroplating bath waste treatment system 324: Heat exchanger 400: Method 402,404,406,408,410,412: Operation steps

The nature and benefits of the disclosed technology can be further understood by referring to the remainder of the specification and the drawings. FIG. 1 is a schematic perspective view of a plating system according to various embodiments of the present technology; FIG. 2 is a partial cross-sectional view of a plating system according to various embodiments of the present technology; FIG. 3 is a schematic view of a plating solution conditioning system according to various embodiments of the present technology; and FIG. 4 is a diagram of a plurality of exemplary operating steps in a method for reducing the formation of insoluble deposits in a plating system. Multiple drawings are provided as schematic drawings. It should be understood that the drawings are used for illustration and should not be considered to be drawn to scale unless it is specifically indicated that the drawings are drawn to scale. In addition, as schematic diagrams, the drawings are provided to aid understanding and may not include all aspects or information compared to the actual situation, and may contain exaggerated parts for the purpose of explanation. In the accompanying drawings, similar components and/or features may have the same component symbols. Moreover, various components of the same type can be distinguished by adding letters that distinguish similar components after the component symbols. If only the previous component symbol is used in the specification, the description also applies to similar components with the same previous component symbol regardless of the letter.

400:Method

402,404,406,408,410,412: Operation steps

Claims (20)

A method for reducing insoluble deposits formed in or on a surface of a plating system, comprising: Reducing the volume of a plating solution having a first pH value in a plating bath from a first volume to a second volume; and Adding a supplement to the plating solution to increase the volume of the plating solution from the second volume to the first volume, wherein the supplement has a second pH value that differs from the first pH value by less than 5 or about 5. The method of claim 1, wherein the pH of the plating solution changes by less than 3 or about 3 after adding the supplement. The method as described in claim 1, wherein the plating solution further comprises metal ions, metal particles, organic metal particles, organic particles, or a combination thereof. A method as described in claim 3, wherein based on the weight of the metal ions, the metal particles, the organometallic particles, the organic particles, or a combination thereof in the plating solution before the addition of the supplement, less than about 10 wt.% of the metal ions, the metal particles, the organometallic particles, the organic particles, or a combination thereof precipitates from the plating solution after the addition of the supplement. The method of claim 1, wherein the first pH value is about 0 to about 5, and the second pH value is about 0 to about 5. The method of claim 1, wherein the first pH value is about 8 to about 12, and the second pH value is about 8 to about 12. The method of claim 1, wherein the second pH value differs from the first pH value by less than 1.5 or about 1.5. The method of claim 7, wherein the second pH value differs from the first pH value by less than 3 or about 3. The method of claim 1, wherein the supplement comprises an inorganic acid, carbonic acid, cathodic water, cathodic water, or a combination thereof. The method of claim 9, wherein the supplement comprises methanesulfonic acid, carbonic acid, cationic water, cationic water, or a combination thereof. The method of claim 10, wherein the pH of the supplement is less than 3. The method of claim 1, wherein reducing the volume of the plating solution comprises evaporating a portion of the plating solution. The method as described in claim 1, wherein the plating solution comprises a first electrolyte concentration and a second electrolyte concentration after adding the supplement, and the first electrolyte concentration differs from the second electrolyte concentration by less than 10 wt.% or about 10 wt.% based on the weight of the electrolyte in the plating solution. A method for reducing insoluble deposits formed in or on a surface of a plating system comprises: Reducing the volume of a plating solution having a first pH value in a plating bath; Adjusting a supplementer to have a second pH value, wherein the second pH value differs from the first pH value by less than 3 or about 3, the supplementer comprising carbonic acid, electrolyzed water, or a combination thereof; and Adding the supplementer to the plating solution to increase the volume of the plating solution. The method of claim 14, wherein the supplement is substantially free of inorganic acids. A method for reducing insoluble deposits formed in or on a surface of a plating system, the plating system comprising a plating bath containing a plating solution having a first pH value, a head including a seal, a substrate coupled to the seal, and a plating bath supply, the method comprising: moving the head from a first position to a second position, wherein the seal and the substrate are disposed in the plating solution in the second position; exposing the substrate to one or more insoluble ions; and adding a supplement to the plating solution, wherein the supplement has a second pH value that differs from the first pH value by less than or about 5. The method as described in claim 16, wherein the electroplating system further comprises a plating liquid regulating system. The method as described in claim 17 further comprises adjusting the supplement to have the second pH value. The method as described in claim 18, wherein adjusting the supplement comprises: selecting an acid, adjusting an acid concentration, adding an acidulant, adding an alkalizing agent, or a combination thereof. The method of claim 19, wherein the acidifying agent and/or the alkalizing agent comprises electrolyzed water.