CN1352703A - Methods for wet processing electronic components having copper containing surfaces - Google Patents

Abstract

This invention provides a method for wet processing of electronic components with copper-containing surfaces. In the method according to the invention, the copper-containing electronic components are contacted with a copper oxide solution containing an oxidant, followed by contact with an etching solution. The method according to the invention is particularly useful for cleaning copper-containing components.

Description

Wet processing method for electronic components having copper-containing surfaces

Cross References to Related Applications

This application claims priority based on US Provisional Patent Application No. 60/135,267, filed May 21, 1999, which is incorporated herein by reference in its entirety.

technical field

The present invention relates to a method for wet processing electronic components having copper-containing surfaces. The method of the invention is particularly useful for cleaning such copper-containing electronic components.

Background technique

Wet processing of electronic components such as semiconductor wafers, flat panels, and other electronic component precursors is widely used in the fabrication of integrated circuits. In order to prepare electronic components, wet processing is required, for example, processing steps include: diffusion, ion implantation, epitaxial growth, chemical vapor deposition, and growth of hemispherical silicon particles, or a combination of these processes. During wet processing, electronic components are exposed to a series of processing solutions. For example, the processing solution can be used to: etch, remove photoresist, clean or rinse electronic components. See U.S. Patent Nos. 4,577,650, 4,740,249, 4,738,272, 4,856,544, 4,633,893, 4,778,532, 4,917,123, and EP 0233 184 to common assignees, and to Burkman et al. Wet Chemical Processes-Aqueous Cleaning Processes from page 111 to page 151 in the Handbook of Semiconductor Wafer Cleaning Technology (Wemer Kern edited, published by Noyes Publication Parkridge, New Jersey in 1993) written, all quoted here for reference.

There are various systems that can be used for wet processing. For example, in a single vessel that is closed to the environment (e.g. the Full-Flow ^TM system offered by CFMT Technologies), in a single vessel that is open to the environment, or in multiple open tanks with multiple working tanks that are open to the atmosphere Electronic components are processed in systems such as wet drawing.

After the treatment process, the electronic components are usually dried. Semiconductor substrates can be dried using various methods, with the goal being to ensure that no contamination occurs during the drying process. Drying methods include drying the wafers by evaporation, centrifugal force in a spin washer dryer, steam, or chemical methods such as those disclosed in US Pat. Nos. 4,778,532 and 4,911,761.

For wet processing methods for cleaning electronic components, many efforts have been made to find suitable methods for treating titanium containing compounds mainly composed of silicon and small amounts such as aluminum, silicon oxide, silicon nitride, titanium or titanium nitride or titanium silicide. , tungsten or tungsten-containing compounds such as tungsten silicide, cobalt silicide, or other components of their combination for cleaning electronic components.

"Cleaning" means a method of removing contaminants, which may be particles, organic matter such as wax, residual polish, or grease or other oxide layer contaminants that adhere to the surface of electronic components.

For silicon-containing electronic components, prior to any metallization step that metallizes the electronic components, it has been found that during the cleaning of silicon-containing electronic components, the electronic Components in contact with "SC2 solution" are very effective. In addition, the cleaning effect can be improved by contacting silicon-containing electronic components with an aqueous solution containing hydrofluoric acid before contacting with the SC1 solution.

The SC1 solution is an aqueous solution containing hydrogen peroxide and ammonium hydroxide, with a bulk density of H ₂ O: _{H 2} O ₂ :NH ₄ OH typically in the range of about 5:1:1 to about 200:1:1. It is believed that the SC1 solution utilizes a surface oxidation/corrosion mechanism for cleaning. For example, it is believed that hydrogen peroxide creates an oxide layer on the surface of silicon-containing electronic components, while ammonium hydroxide etches or removes the resulting oxide from the surface. Finally, a steady state is reached when the surface is simultaneously grown and etched to produce a thin (eg, about 1 nm) oxide layer. Oxide growth and corrosion can loosen adhering particles and other contaminants. Once loosened, adherent particles and other contaminants can be removed from the surface of electronic components.

After contact with the SC1 solution containing hydrogen peroxide, the SC2 solution to which the silicon-containing electronic components were exposed contained hydrogen peroxide, hydrochloric acid, and water. The bulk density of H ₂ O:H ₂ O ₂ :HCl in the SC2 solution is usually in the range of about 5:1:1 to 1000:0:1. SC2 is used to remove any metal deposits (eg iron, aluminum and copper deposits) that develop during contact of electronic components with the SC1 solution. Due to the improved chemical purity in the SC2 solution, metal precipitates are now less of an issue and the SC2 solution treatment step is often omitted.

If the surface of an electronic component is treated to contain a metal such as aluminum, the amount of aqueous wet processing solution used can be greatly reduced. For example, many metals such as aluminum corrode severely when in contact with aqueous solutions. Therefore, solvents are usually used instead of aqueous solutions for wet processing of metal-containing electronic components. However, the use of solvents is not ideal because of environmental concerns such as the handling and recycling of the solvents, and raises safety risks such as flammability.

More recently, electronic component manufacturers have begun replacing aluminum with copper in electronic components. The desire to replace aluminum with copper is primarily due to the low electrical resistance of copper. Copper also has the advantage of good corrosion resistance. However, little is known about how to clean copper-containing electronic components using aqueous solutions.

U.S. Patent No. 4,714,517 to Malladi (hereinafter referred to as "Malladi") discloses a method of cleaning copper parts using a semiconductor device with automatic limitation. Copper parts are treated with organic acids such as acid, tartaric acid to passivate the surface. However, Malladi does not provide a method for controlling the copper corrosion process during cleaning.

The present invention provides additional methods for wet processing electronic components having copper-containing surfaces. The wet processing method according to the invention preferably uses conventional solutions used in the wet processing of silicon electronic components. The method according to the invention is particularly suitable for removing particulate contaminants from the surface of copper-containing electronic components while allowing the amount of copper corrosion on the electronic components to be controlled.

SUMMARY OF THE INVENTION

The present invention provides methods for wet processing electronic components having copper-containing surfaces. The method according to the present invention comprises: contacting the surface of the electronic component with the copper oxide solution for a first contact time; subsequently contacting the surface of the electronic component with the etching solution for the second contact time. The etchant maintains an aqueous pH of 5 or less and contains etchant and less than 5,000 ppb dissolved or suspended oxygen. The contact of the surface of the electronic components with the copper oxide solution and the etchant can remove the contamination from the surface of the electronic components. Using the two steps described above, the amount of metal removal and/or corrosion during wet processing of copper-containing electronic components can be controlled.

In a preferred embodiment, the present invention provides a method of wet processing electronic components having copper-containing surfaces, the method comprising: placing one or more electronic components in a container; The copper oxidation solution is injected into the container; the electronic components are brought into contact with the copper oxidation solution within a first contact time; and the copper oxidation solution is removed from the container. Subsequently, the method also includes: injecting hydrofluoric acid containing a solution having a pH value of 5 or lower and having less than 5000 ppb dissolved oxygen or suspended oxygen into the container; contact with the solution of hydrofluoric acid; and remove the solution containing hydrofluoric acid from the container, wherein the surface of the electronic component is in contact with the copper oxide solution and the solution containing hydrofluoric acid to remove contaminants from the surface of the electronic component.

Brief description of the drawings

FIG. 1 shows a histogram of the percent particle removal for electronic components with copper-containing surfaces treated according to Comparative Examples 1 to 4 and Example 5. FIG.

Detailed Description of the Invention

The present invention provides methods for wet processing electronic components having copper-containing surfaces. For example, the method according to the present invention is particularly suitable for cleaning electronic components to remove contaminants (eg particles), organic compounds, polishing agents, grease, or oxide layers adhering to the surface of the electronic components.

The method according to the invention can be used in any wet process requiring cleaning of electronic components having copper-containing surfaces. "Wet processing" means that electronic components are contacted with one or more liquids (hereinafter referred to as "processing liquid") to process electronic components in a required manner. For example, processing of electronic components is required to clean, etch, or remove photoresist from the surface of the electronic components. Rinsing of electronic components is also required between these processing steps. Wet processing also includes the step of contacting the electronic components with other fluids such as gases, vapors, or liquids mixed with vapors or gases, or combinations thereof. As used herein, the term "fluid" includes liquids, gases, liquids in the gas phase, or combinations thereof. Typically, this wet processing process is performed to utilize copper to fabricate electronic components, and the processing steps include dielectric chemical vapor deposition, plasma etching, or reactive ion etching, or a combination thereof.

There are many kinds of treatment fluids used in wet treatment. In general, the most common treatment fluids used in wet processing are: chemical treatment fluids or fluids and rinse fluids or flushing fluids. As used herein, a "chemical treatment fluid" or "chemical treatment fluid" is any liquid or fluid that reacts in some way with the surface of an electronic component to change its surface composition. For example, chemical treatment liquid or chemical treatment fluid has the activity of removing contaminants (such as particles, metal materials, photoresists, or organic substances) that adhere to or chemically bond to the surface of electronic components , or have the activity of corroding the surface of electronic components, or have the activity of growing an oxide layer on the surface of electronic components. The chemical treatment fluids used in the present invention contain one or more chemical reactants to achieve the desired surface treatment. The concentration of these chemically active agents is preferably greater than 1000 ppm and more preferably greater than 10,000 ppm by weight of the chemical treatment fluid. The chemical treatment fluid may also contain 100% of one or more chemical reactants. Examples of the chemical treatment liquid used in the method of the present invention will be described in more detail below.

As used herein, "rinse fluid" or "rinse fluid" means DI water or some other liquid or fluid used to clean electronic components and/or containers of residual chemical treatments, chemical reaction by-products and/or chemical Particles or other contaminants released or loosened by a processing step. Rinse fluids or flushing fluids also prevent loose particles or contaminants from re-depositing on electronic components or containers. Examples of rinsing solutions used in the method of the present invention are described in more detail below.

As used herein, "chemical processing step" or "wet processing step" refers to exposing the individual electronic components to a chemical processing fluid or processing fluid, respectively.

"Electronic component having a copper-containing surface" means that the electronic component preferably has at least about 0.1% of its total surface area covered with copper. The thickness of the copper on the surface is preferably at least about 0.1 microns and more preferably from about 0.5 microns to about 5 microns. Thus, the electronic components are at least partially covered with copper. In the case of partial coverage, electronic components can be covered with copper regular patterns. Examples of electronic components with copper-containing surfaces include: electronic component precursors used in the manufacture of electronic components such as integrated circuits, such as semiconductor wafers, plates and other components; CD ROM disks; hard disks; or multi-chip module.

In the wet processing method according to the present invention, an electronic component having a copper-containing surface is contacted with a copper oxidizing solution and then with an etching solution containing less than 5000 ppb dissolved and suspended oxygen. Although there is no way to limit it theoretically, it is believed that copper oxidizing solutions oxidize copper-containing surfaces (eg, from Cu ⁰⁺ to Cu ²⁺ ) to form thin copper oxide layers (eg, less than about 1.0 nm) or different A combination of copper oxides. It is believed that the etchant can etch the copper oxide layer in controlled proportions.

The copper oxidizing liquid that electronic components come into contact with is any liquid that can oxidize copper on the surface of electronic components. The copper oxidizing solution should also preferably not contain solvents that would corrode copper. The copper oxidizing solution preferably maintains a pH of at least about 7 or greater, and more preferably maintains a pH of at least about 8 to avoid corrosion of copper. In order for the copper oxidizing solution to maintain this pH, the copper oxidizing solution should preferably not contain acids (eg HCl, HF, nitric acid) in amounts that would bring the pH below 7.

For example, suitable copper oxidizing solutions include solutions containing oxidizing agents such as hydrogen peroxide, ozone, ferric cyanide, or combinations thereof. The oxidizing agent is preferably hydrogen peroxide. These oxidizing agents are preferentially dissolved or suspended in any compatible liquid, for example: water, aqueous alkaline solutions, or non-oxidizing organic solvents such as fluorohydrocarbons, or combinations thereof. The oxidizing agent can also be a solution that does not have to be a solution in which the oxidizing agent is dissolved. The oxidizing agent is preferentially dissolved or dispersed in water.

The concentration of oxidant in the copper oxidizing solution depends on the oxidant chosen. Usually, the oxidant contained in the copper oxidation solution is preferably between about 0.1 volume percent and 100 volume percent relative to the total volume of the solution, more preferably between about 10 volume percent and about 70 volume percent. For hydrogen peroxide, relative to the total volume of the copper oxidation solution, the concentration of hydrogen peroxide in the copper oxidation solution is preferably between about 0.1 volume percent to about 10 volume percent, more preferably about 0.2 volume percent to about 1.0 volume percent between. Regarding ozone, the concentration of ozone in the copper oxidizing solution is preferably between about 10 ppm and about 50 ppm, more preferably between about 10 ppm and about 40 ppm.

In a preferred embodiment of the present invention, the copper oxidizing solution is an SC1 solution, in which the ratio of _{H2O :H2O2 : NH4OH} is preferably about 5:1:1 to 200:1 according to the volume :1, more preferably between about 50:1:1 and 150:1:1, most preferably between about 90:1:1 and about 110:1:1.

In order to improve the wet treatment process, the copper oxidation solution may contain other active agents in addition to the oxidizing agent. For example, the copper oxidation solution may also contain surfactants, corrosion inhibitors, or any other conventional active agent commonly added to wet processing fluids for cleaning. The amount of these active agents added to the copper oxidizing solution is preferably less than 5.0 volume percent, and more preferably between about 0.01 volume percent and about 1.0 volume percent.

If it is required to contain a surfactant in the copper oxidizing solution, the amount of the surfactant in the copper oxidizing solution is preferably less than 1 volume percent, and more preferably less than 0.5 volume percent, relative to the total volume of the copper oxidizing solution. For example, surfactants that may be used include: anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants, as described, for example, in Kirk-Othber Concise Encyclopedia of Chemical Technology, published by John Wiley & Sons, NY, 1985, pp. 1142-1144 and McCutcheon's Detergents and Emulsifiers, 1981 North American Edition, MC Publishing Company, Glen Rock, NJ 1981 , all of which are incorporated herein by reference. Preferred surfactants for use in the present invention include alkaline surfactants and ^VALTRON® surfactants such as: ^VALTRON® SP2275 and SP2220 available from Valtech Corporation of Pughtown, PA, NCW601A available from the Wako Company.

If it is required to contain a corrosion inhibitor in the copper oxidation solution, the amount of the corrosion inhibitor added to the copper oxidation solution is between about 0.1 weight percent and about 1.0 weight percent relative to the total weight of the copper oxidation solution. For example, examples of corrosion inhibitors that can be used include benzotriazoles.

Electronic components are preferentially exposed to copper oxide solution within a certain contact time, which is enough to ensure that a uniform copper oxide layer is formed on the entire wafer, and some particles that need to be removed will be generated due to the copper oxidation process and the dissolution process of copper oxide. "Contact time" as used herein refers to the time an electronic component is exposed to a processing fluid. For example, contact time includes: the time during which the electronic components are exposed to the processing liquid during the filling of the processing liquid into the container or during the immersion of the electronic components in the processing liquid; the time that the electronic components are immersed in the processing liquid; The exposure time of electronic components to the processing liquid when the processing liquid or electronic components are taken out of the container. The actual selection of the contact time depends on these factors, namely the oxidizing agent added to the copper oxidizing solution, the concentration of the oxidizing agent and the temperature of the copper oxidizing solution. However, the contact time is preferably at least 30 seconds and not more than 10 minutes.

During contacting, the temperature of the copper oxidizing solution is such that decomposition of the oxidant in the copper oxidizing solution is avoided. The temperature of the copper oxidizing solution is preferably below 60°C, and more preferably between about 20°C and about 40°C.

Contacting electronic components with the copper oxide solution can be accomplished using any known wet processing technique, depending primarily on the wet processing system selected. For example, one or more electronic components may be dipped in a bath containing a copper oxidizing solution and pulled. Alternatively, the electronic components may be placed in a container and then the copper oxide solution may be passed across the container to fill the container to achieve contact. Can be under dynamic conditions (e.g. passing a solution across a container containing electronic components), under static conditions (e.g. submerging electronic components in the solution), or a combination of the two (eg: solution traversing the container for one period of time, and then submerging electronic components in solution for another period of time) to achieve contact. Suitable wet processing systems for contacting electronic components are described in more detail below.

After the electronic components are brought into contact with the copper oxide solution, the electronic components are brought into contact with the etching solution. An etchant is any solution containing an etchant that can corrode copper oxide. The etchant preferably contains one or more non-oxidizing acids (eg, acids that do not oxidize copper) so as to maintain the pH of the etchant at about 5 or less. The amount of etchant in the etchant is preferably such an amount that the pH of the etchant is maintained at about 5 or less, more preferably such an amount is maintained at a pH of about 4 or less, Most preferred is an amount that maintains the pH of the etchant at about 3 or lower. Examples of non-oxidizing acids useful in the present invention include hydrochloric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, organic acids such as acetic acid, citric acid, or tartaric acid, or combinations thereof. The solution for dissolving or dispersing the etchant is preferably water, but may also be an organic solvent such as ethylene glycol, propylene carbonate, methanol, or combinations thereof.

In a preferred embodiment according to the present invention, the etching solution is a solution containing hydrofluoric acid. The solution containing hydrofluoric acid may contain hydrofluoric acid, buffered hydrofluoric acid, ammonium fluoride, or any other substance that can generate hydrofluoric acid in solution, or a combination thereof. The hydrofluoric acid in the hydrofluoric acid solution is preferably in a volume ratio of _H2O: HF of about 5:1 to about 1000:1, more preferably in a volume ratio of H2O: _HF of From about 100:1 to about 800:1, and most preferably a volume ratio of _H2O :HF from about 200:1 to about 600:1.

It has been found in accordance with the present invention that it is desirable to maintain the etchant in such a way as to facilitate a slow controlled etch rate (eg, copper is etched at a rate of less than about 10 nm per minute, and more preferably less than about 1 nm per minute). Copper is best etched at a slow controlled etch rate, so that the least amount of copper needs to be removed to clean electronic components. Factors affecting the copper corrosion rate include: the concentration of etchant in the etching solution, the pH value of the etching solution, the amount of dissolved or suspended oxygen or other oxidizing agents in the etching solution, and the temperature of the etching solution. For example, the corrosion rate of copper can be reduced by reducing the concentration of etchant, dissolved or suspended oxygen, and other copper oxidizing agents in the etchant, increasing the pH and reducing the temperature of the solution. Among the above factors affecting the copper corrosion rate, the amount of dissolved oxygen or suspended oxygen or other copper oxidants in the etching solution may be the most important factor affecting the copper corrosion rate. This is because oxygen or other copper oxidizing agents react with copper to form copper oxide, and the copper oxide can be easily corroded at this pH of the etchant.

The concentration of dissolved or suspended oxygen in the etching solution is preferably kept below 5000 ppb relative to the total weight of the etching solution, more preferably kept below 100 ppb, and most preferably kept as low as possible. In addition, the concentration of other copper oxidizing agents (eg, copper oxidizing agents such as _H2O2 used in the copper oxidizing solution) is preferably kept below 5000 ppb, _more preferably kept below 100 ppb, and most preferably kept as low as possible. As noted above, maintaining such low concentrations of dissolved or suspended oxygen or other copper oxidizing agents can reduce the rate of copper corrosion and thereby control corrosion.

As mentioned above, the pH of the etchant is preferably maintained at about 5 or less, more preferably at about 4 or less, and most preferably at about 3 or less. In addition to the etchant, buffering agents can be added to the etchant to help maintain the pH within the above range. The amount of buffer added is preferably sufficient to maintain the pH within the above preferred range. The amount of buffer in the etchant is preferably between about 0.01 weight percent and about 5.0 weight percent, and more preferably between about 0.05 weight percent and about 0.5 weight percent, based on the total weight of the etching solution.

In a preferred embodiment according to the present invention, the etching solution contains hydrofluoric acid and hydrochloric acid. Hydrochloric acid was chosen because it helps lower the pH and keeps the zeta potential of the surface positive so that the particles repel each other. For 1 volume fraction of hydrofluoric acid, the _H2O :HCl volume ratio of hydrochloric acid in the etching solution is preferably between about 50:1 and about 1000:1, more preferably between about 500:1 and about 500:1 10, and most preferably between about 500:3 and about 500:7.

In addition to the etchant, the etchant may contain other additives to improve the wet processing. For example, the etchant may contain surfactants, corrosion inhibitors, or any conventional additives commonly added to wet processing fluids for cleaning. The amounts of these additives in the etching solution are preferably the same as those described above for the copper oxidizing solution.

The electronic component is preferentially exposed to the etchant for a contact time sufficient to remove oxides formed during the contact of the electronic component with the copper oxidizing solution. The choice of contact time depends on these factors: the concentration of etchant and dissolved or suspended oxygen in the etchant, the pH and temperature of the etchant, and the type of etchant used. However, the contact time is preferably at least 30 seconds and not more than 2 minutes.

The temperature of the etchant during contact is so high that the etching process can be controlled and a slow etching rate (eg, about 10 nm or less etched per minute) can be achieved. The temperature of the etchant is preferably below 50°C, and more preferably between about 20°C and about 30°C.

The electronic components can be exposed to the etchant using the wet processing techniques described above for exposing the electronic components to the copper oxide solution. For example, one or more electronic components may be dipped into a bath containing an etchant and pulled. Alternatively, electronic components may be placed within the container and the etchant may be passed across the container to fill the container to achieve contact. Furthermore, contact can be achieved dynamically, statically, or a combination of both.

In a preferred embodiment of the present invention, in an effort to minimize the concentration of dissolved oxygen or suspended oxygen, the electronic components and etching solution are isolated from the oxygen source (for example: isolated from the air) environment, the electronic Components come into contact with etchant. This isolation process is accomplished in an environmentally closed system (described in more detail below), or in a system surrounded by an inert gas such as nitrogen or a rare gas such as argon.

Also, because copper is susceptible to reoxidation after treatment with etchant, any fluid that comes into contact with electronic components (whether chemically treated or rinsed) after contact with etchant should contain a small amount of dissolved or suspended oxygen Or copper oxidizing agent (for example: copper oxidizing agent used in copper oxidizing solution). These fluids preferably contain less than about 500 ppb dissolved or suspended oxygen, more preferably less than 50 ppb, and most preferably as little as possible, based on the total weight of the fluid. The fluid preferably contains less than 500 ppb, more preferably less than 50 ppb, and most preferably is free of other copper oxidizing agents. Due to the presence of small amounts of dissolved or suspended oxygen and small amounts of copper oxidizing agents in these fluids, the risk of re-oxidation of the surface of electronic components after treatment with etching solutions is significantly reduced.

In addition to exposing electronic components to copper oxide and etchant solutions, electronic components are also exposed to several other chemical processing fluids (eg, gases, liquids, vapors, or any combination thereof) to achieve the desired results. For example, electronic components can be exposed to corrosion (hereinafter referred to as corrosion fluid), growth of oxide layer (hereinafter referred to as oxidation growth fluid), elimination of photoresist (hereinafter referred to as photoresist removal fluid), improvement of cleaning process (hereinafter referred to as cleaning fluid) or their combination of chemical treatment fluid. In wet processing methods, electronic components can be rinsed at any time with a rinse fluid. The chemical treatment fluid and the flushing fluid are preferably liquids.

Those skilled in the art recognize that a variety of treatment fluids can be used during wet processing. In "Chemical Etching" by Werner Kern et al., in ThinFilm Processes, edited by John L. Vosser et al., published by Academic Press, NY 1978, pages 401-496 for treatment fluids that may be used during wet processing Examples of gases are disclosed and are incorporated herein by reference in their entirety.

Electronic components are exposed to flushing fluids in addition to chemical process fluids. As noted above, the rinse fluid is used to clean the electronic components and/or containers of residual chemical processing fluid, chemical reaction by-products, and/or particles or other contaminants released or loosened by chemical processing steps. Flushing fluids can also be used to prevent loose particles or contaminants from re-depositing on electronic components or containers.

Any flushing fluid effective to achieve the above can be selected. In selecting a rinse fluid, factors that should be considered include: the surface properties of the electronic components to be rinsed, the properties of the contaminants dissolved in the chemical process fluid, and the properties of the chemical process fluid to be rinsed. In addition, the proposed flushing fluid should be compatible (ie, chemically non-reactive) with the materials of the structures in contact with the fluid. For example, flushing fluids that may be used include: water, organic solvents, mixtures of organic solvents, or combinations thereof. Preferred organic solvents are anhydrous organic solvents as described below, for example: C ₁ to C ₁₀ alcohols, and preferably C ₁ to C ₆ alcohols. The flushing fluid is preferably liquid and contains a small amount of oxygen (eg: preferably less than 5000 ppb, more preferably less than 500 ppb, and most preferably less than 100 ppb). In the most preferred embodiment, the flushing fluid is deionized water.

The flushing fluid may also optionally contain small amounts of chemically active agents to improve flushing. For example, surfactants and/or corrosion inhibitors may be used in the flushing fluid. The concentration of these additives in the flushing fluid is very low. For example, the concentration preferably does not exceed 1000 ppm, more preferably does not exceed 100 ppm by weight relative to the total weight of the flushing fluid.

It will be apparent to those skilled in the art that the choice of chemical treatment fluid and sequence of chemical treatment fluids will depend upon the desired wet processing outcome. For example, before or after one or more chemical processing steps, the electronic components are contacted with the rinsing fluid. On the other hand, certain other wet processing methods require that one chemical processing step be followed by another chemical processing step without exposing the electronic components to a rinsing fluid between chemical processing steps (ie, without intermittent rinsing). Such continuous wet processing without intermittent rinsing is disclosed, for example, in US Patent Application Serial No. 08/684,543, filed July 19, 1996, which is incorporated herein by reference in its entirety.

Furthermore, for example, in one embodiment according to the present invention, it is preferable to expose the electronic components to a rinsing fluid such as water to wet the surface of the electronic components prior to contacting the copper oxidizing solution. During this wet processing step, the temperature of the flushing fluid is preferably between about 20°C and 60°C and more effectively between about 20°C and 40°C. It is also desirable to add surfactants to this flushing fluid, preferably in the amounts described above for copper oxidizing fluids.

In another embodiment according to the invention, the electronic components are contacted with a rinsing fluid after the electronic components are contacted with the copper oxidizing solution but before said electronic components are contacted with the etching solution. The flushing fluid is preferably deionized water at a temperature of about 20°C to 60°C. As explained here, the flushing fluid preferably also has a small amount of oxygen. Electronic components are preferentially exposed to the flushing fluid for a contact time sufficient to remove residual chemicals, chemical reaction by-products, and/or particles or other contaminants released upon contact with the copper oxidizing fluid. However, it is also possible to expose the electronic components to the etching solution directly after exposing the electronic components to the copper oxidizing solution, without interposing a rinsing step between these two chemical treatment steps.

After exposing the electronic components to the etchant, in the present invention the electronic components are preferentially exposed to a deionized water rinse fluid at a temperature between about 20°C and about 60°C. This rinsing step is prioritized to remove residual chemicals, chemical reaction by-products, released particles or other contaminants that remain on the surface of the container or electronic component after the electronic component has been exposed to the etchant. The flushing fluid used in this step preferably contains a small amount of dissolved or suspended oxygen (as described above) to minimize the risk of copper re-oxidation.

As mentioned above, it is required to add a surfactant to the treatment liquid used in the present invention. Preferably, one or more surfactants are included in the treatment liquid (including copper oxide, etchant or rinse) and the electronic components are exposed at the air-liquid interface. For example, the electronic components are exposed to the air-liquid interface during immersion or pulling of the electronic components in the processing liquid. Electronic components are also exposed to the gas-liquid interface during injection of the process liquid into the container. Surfactants have been found to help reduce particle settling or sticking in several ways. For example, surfactants can be enriched in the liquid at the air-liquid interface (ie, at the liquid surface) to expel particles at the liquid surface. By minimizing particles at the liquid surface the likelihood of surface particles contacting electronic components is reduced. In addition, surfactants also provide an electrochemical barrier to avoid particle adhesion. For example, surfactants will concentrate on liquid surfaces, solid surfaces or other surfaces thereby helping to reduce their overall energy, including particles and electronic components. Since the electronic components and particles are surrounded by surfactant on all sides, the total charge of the particle/surfactant and semiconductor substrate/surfactant is close to that of the surfactant. Since the particles and semiconductor substrate have the same charge as the surfactant, they do not attract each other like opposite charges, thereby avoiding sticking to other particles during immersion. Surfactant selection is based on wet processing steps. For example, the pH of the surfactant should be compatible with the pH of the chemical treatment fluid (eg, alkaline surfactants are preferred in copper oxidizing fluids and acidic, non-oxidizing surfactants are used in etching fluids).

In the most preferred embodiment according to the present invention, the electronic components are contacted as SC1 solution with a copper oxide solution at a temperature of about 25° C. for a contact time of about 3 minutes or less. Depending on the volume of the copper oxidizing solution, this SC1 solution preferably contains water, ammonium hydroxide and hydrogen peroxide in a volume ratio of 100:1:1, respectively, and less than 1% by volume of surfactant. Then, preferably rinse the electronic components with deionized water at about 25°C for a contact time of about 5 minutes. After rinsing, the electronic components are preferably exposed to a solution containing hydrofluoric acid at a temperature of about 25°C for a contact time of less than about 2 minutes. The hydrofluoric acid-containing solution preferably contains water, hydrofluoric acid and hydrochloric acid in a volume ratio of approximately 500:1:5, respectively. Rinse the electronic components with deionized water at a temperature of about 25° C. for about 5 minutes, and then dry them with isopropanol at a temperature of about 25° C. for about 1 minute.

In another preferred embodiment according to the present invention, the wet treatment process is carried out according to the above-mentioned most preferred embodiment, except that the copper oxidation solution contains water and hydrogen peroxide in a volume ratio of approximately 100:1, respectively. The copper oxidizing solution also preferably contains a surfactant in the above amounts, but does not contain ammonium hydroxide.

Therefore, there are many ways to carry out wet processing of electronic components according to the method of the present invention. For example, wet processing using acoustic energy (eg, in the high acoustic energy range, eg, between about 500 kHz to about 1 MHz) may be used to improve cleaning during the exposure of the electronic components to the processing fluid. Additionally, methods are described in, for example, U.S. Patent Nos. 5,383,484, 08/684,543 filed July 19, 1999, 09/209,101 filed December 10, 1998, and 09/253,157 filed February 19, 1999. U.S. Patent Application Nos., and U.S. Provisional Patent Applications No. 60/087,758, filed June 2, 1998, and U.S. Provisional Patent Applications No. 60/111,350, filed December 8, 1998, are disclosed herein All cited for reference.

In general, the method of the present invention is carried out in any wet processing equipment including, for example: multi-tank systems (eg: wet drawing), single-vessel systems (open or closed to the environment)). Please refer to e.g. Chapter 1: Overview and Evolution of Semiconductor Wafer Contamination and Cleaning Technology by Werner Kern and Chapter 3: Aqueous Cleaning Processes by Con C.Burkman, Donald Deal, Donald C.Grant, and Charlie A.Peterson in Handbook ning of Semiconductor Cleasing ( edited by Werner Kern, Published by NoyesPublication Parkridge, New Jersey 1993), and Wet Etch Cleaning by Hiroyuki Horiki and Takao Nakazawa in Ultraclean Technology Handbook, Volume 1, (edited by Tadahiro Ohmikerpublished by Marek), all cited herein by reference.

In a preferred embodiment according to the invention, electronic components are housed in a single container system. Single-container systems are preferred, such as in Nos. 4,778,532, 4,917,123, 4,911,761, 4,795,497, 4,899,767, 4,984,597, 4,633,893, 4,917,123, 4,738,272, 4,577,650 No. and US Patent No. 5,569,330, the entirety of which is incorporated herein by reference. Preferred commercially available single vessel systems are Full-Flow ^™ vessels such as Full-Flow ^™ vessels manufactured by CFM Technologies, Poseidon manufactured by Steag, and FL820L manufactured by Dainippon Screen. These systems are preferred because they provide easier control over the amount of oxygen.

In the most preferred embodiment according to the present invention, the electronic components are subjected to wet processing in a closed wet processing system to reduce the exposure time of the electronic components to oxygen, so that the surface of the electronic components to be cleaned is re-oxidized risk is minimized. The closable wet processing system preferentially receives the different processing fluids in various sequences. The preferred method of feeding treatment fluids into the container is direct displacement of one fluid by another fluid. The Full-Flow ^™ wet processing system manufactured by CFM Technologies is an example of an input fluid by direct replacement.

In a preferred method according to the invention using a single sealable container, one or more electronic components are placed within the processing container and sealed from the environment. Optionally, the electronic components may be pretreated by exposing the electronic components to a rinse fluid or any other desired treatment fluid prior to exposing the electronic components to the copper oxidizing solution. This contacting process is accomplished by flooding the process vessel with the fluid across it so that very little airborne gases or residual fluids from previous steps are sealed within the vessel. The fluid can be continued across the container to fill the container in one go, or the fluid flow can be stopped to allow the electronic components to soak for a desired time. After this pretreatment step, the fluid currently in the container is drained from the container, and the copper oxidizing solution is then injected into the container to expose the electronic components to the copper oxidizing solution. After exposure to the copper oxidizing solution, the electronic components may optionally be rinsed and then exposed to an etchant such as a solution containing hydrofluoric acid. After exposure to etchant, the electronic components may optionally be rinsed or treated in any other manner required.

Purging of one treatment fluid with another treatment fluid within a single closable container can be accomplished in a number of ways. For example, the treatment fluid may be completely purged (ie drained) from the treatment vessel, and then, either during or after the drain, the next treatment fluid may be injected into the vessel. In another embodiment, the treatment fluid in the container can be replaced by the next treatment fluid, as disclosed in US Patent No. 4,779,532.

Drying of electronic components is a priority after wet processing with chemical treatment fluids and rinse fluids. "Drying" or "drying" means preferentially substantially removing the droplets from the electronic component. By removing the droplets during drying, impurities within the droplets do not remain on the surface of the semiconductor substrate when the droplets are evaporated. These unwanted impurities can leave marks (eg watermarks) or other residues on the surface of the semiconductor substrate. However, it is also conceivable that the drying process simply involves removing the treatment or flushing fluid with a stream of drying fluid or with other methods known to those skilled in the art.

Any drying method or drying system can be used. For example, suitable drying methods include: evaporation methods, centrifugal force drying in a spin washer dryer, steam drying or chemical drying or combinations thereof.

The preferred drying method utilizes a drying fluid flow that directly replaces the last treatment fluid that the electronic component was exposed to prior to drying (hereinafter referred to as "direct replacement drying process"). Suitable methods and systems for direct replacement drying are disclosed, for example, in US Pat. Other direct replacement desiccants that may be employed include Marangoni type desiccants supplied by manufacturers such as Steag, Dainippon and YieldUp. Most preferably, the system and method disclosed in US Patent No. 4,911,761 is used for drying electronic components.

The drying fluid stream preferably consists partly or completely of vaporized drying liquid. For example, the drying fluid stream may be a mixture of ultra-high temperature steam and liquid, saturated steam, or a mixture of steam and non-condensable gas.

The drying fluid constituting the drying fluid stream is selected to be compatible with the last-used processing fluid in the container and to be non-chemically reactive with the surface of the electronic components. The drying liquid also preferably has a reduced boiling point, which facilitates the drying. For example, it is preferentially selected from among organic compounds whose boiling point is lower than 140 degrees Celsius at atmospheric pressure. Examples of drying fluids that may be used include: steam, such as methanol, ethanol, 1-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, or tert-amyl alcohol, acetone, acetonitrile, hexafluoroacetone , nitromethane, acetic acid, propionic acid, ethylene glycol monomethyl ether, difluoroethane, ethyl acetate, isopropyl acetate, 1,1,2-trichloro-1,2,2-trifluoroethane alkanes, 1,2-dichloroethane, trichloroethane, perfluoro-2-butyltetrahydrofuran, perfluoro-1,4-dimethylcyclohexane or combinations thereof. The drying liquid is preferably a _C1 to _C6 alcohol, such as methanol, ethanol, 1-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, tert-amyl alcohol, pentanol, hexanol or their combination.

In a preferred embodiment according to the invention, the drying liquid is selected to be compatible with and form a minimum azeotropic mixture with the processing liquid present in the processing vessel prior to drying. Since water is the most convenient and most commonly used solvent for chemical treatment fluids or flushing fluids, drying fluids especially preferentially form the lowest azeotropic mixture with water.

To reduce the risk of re-oxidation and contamination of electronic components, wet processing and drying in a single container is preferred, without removing the electronic components from the container. For example, suitable wet processing systems that implement a wet processing process and a drying process in a single vessel include: Full Flow ^™ wet processing system manufactured by CFM Technologies, Poseidon manufactured by Steag, and FL820L manufactured by Dainippon Sereen.

After the drying process, the electronic components are removed from the drying container and processed further in the desired manner.

The electronic components obtained by the method of the present invention can substantially eliminate particle contamination. "Substantially eliminated" means that the semiconductor substrate contains preferably less than 0.05 particles per cm ² , and more preferably less than 0.016 particles per cm 2 . The diameter size of the particles remaining on the semiconductor substrate is preferably equal to or smaller than 0.3 μm, and more preferably smaller than 0.12 μm, as measured by a KLA Tencor SPI particle scanning device. Particles larger than 0.3 μm are preferentially removed by the method of the present invention.

The method according to the invention is particularly suitable for removing non-metallic particles from the surface of electronic components. For example, non-metallic particles include: SiO ₂ , Si ₃ N ₄ , organic substances, or combinations thereof. example

The method according to the invention is used for the wet processing of semiconductor wafers with copper-containing surfaces. In all examples, the copper-containing wafers were made of silicon and silicon oxide and were fully plated with a 400 nm layer of copper. After wet processing, the particles on the wafers were analyzed using a Tencor SPI scanning device from KLA Tencor. Comparative Examples 1 to 3

Copper-containing wafers were filled in a Full Flow ^™ 8100 wet processing system manufactured by CFM Technologies. The container was filled with the chemical treatment fluid shown in Table 1 for Comparative Example 1 at a rate of 12 gallons per minute with a total injection time of 120 seconds. The temperature of the chemical treatment liquid was 30°C. After the container is filled, the wafer is immersed in the chemical treatment solution for 120 seconds. During exposure of the wafer to the chemical treatment fluid, the wafer was exposed to high acoustic energy at a frequency of about 650 KHz for about 1 minute.

Then, directly replace the chemical treatment solution with deionized water rinse solution at 30°C and containing at least 100ppb oxygen. Deionized water was introduced into the treatment vessel at a rate of 24 g/m for 60 seconds and then circulated at a rate of 12 g/m for 60 seconds. This cycle was repeated until the deionized water in the treatment vessel had a resistance of 5 megohms. After this resistance is reached, additional time is used to allow continuous circulation of deionized water into the treatment vessel. The total rinse time was greater than 3 minutes and during rinse the wafer was exposed to high sonic energy.

After rinsing, the wafer was dried using a stream of isopropanol gas drying fluid. Isopropanol gas was passed across the process vessel at 45°C for 9 minutes at a pressure of 1.5 psig.

The other two batches of wafers can be processed in the manner described above, using a total of 3 rounds.

Three wafers from each lot were then analyzed for particulate contamination ranging in size from 18 microns to 400 microns using 6mm edge exclusion. The average results are shown in Table 2.

The above process was repeated for each comparative chemical treatment solution shown in Table 1. For each comparative example, except comparative example 3, the treatment process was the same as above, injecting the chemical treatment liquid into the container at a rate of 18 g/m, and then, after the injection was completed, the electronic unit was placed in the absence of high acoustic energy. The device is soaked for 1 minute. In addition, the electronic components in Comparative Example 3 were rinsed according to the procedure employed in Comparative Example 1, except that the temperature of the rinse liquid was 45° C. and the total rinse time was about 2 minutes.

Table 1: Composition of Chemical Treatment Fluids example Composition of chemical treatment fluid (part by volume) H ₂ O _{H2O2 _} NH ₄ OH HF HCl Surf ¹ Example 1 (only utilize copper oxide solution to process) 100 1.3 2.2 0.0 0.0 0.6 Example 2 ² (Treatment with _NH4OH only without oxidizing agent or HF) 100 0.0 2.2 0.0 0.0 0.6 Example 3 ² (Treatment with HF-containing solution only) 100 0.0 0.0 0.2 1.0 0.0

¹ Surfactant, ^VALTRON® SP2200 provided by Valtech.

² Contains less than 100ppb of oxygen Comparative Example 4 - firstly utilize NH ₄ OH without oxidizing agent for treatment, and then utilize HF-containing solution for treatment

The Full Flow containers used in Comparative Examples 1 to 3 were filled with copper-containing discs. Inject the first chemical treatment liquid into the container, the temperature of the first chemical treatment liquid is 30°C, and its composition proportion is 100:2.2:0.6 H ₂ O:NH ₄ OH:surfactant and less than 100ppb oxygen. Inject the first chemical treatment liquid into the container at a speed of 12 g/m in 120 seconds. After being filled into the container, the wafer is then soaked in the first chemical treatment solution for 120 seconds. During exposure of the wafer to the first chemical treatment fluid, the wafer was exposed to high acoustic energy at about 650 KHz.

Then, according to the treatment process adopted in Comparative Example 1, the first chemical treatment solution was directly replaced with a deionized water rinse solution (oxygen content lower than 100 ppb). Then, directly replace the flushing solution with the second chemical treatment solution, the temperature of the second chemical treatment solution is 30° C., and the composition ratio of the second chemical treatment solution is 100:0.2:1 H ₂ O:HF:HCl and oxygen less than 100 ppb by volume . The second chemical treatment solution was injected into the container at a rate of 18 g/m with a total injection time of 120 seconds. After pouring into the container, the wafer was then soaked in a second chemical treatment solution (without high sonic energy) for 120 seconds.

Then, according to the treatment process employed in Comparative Example 3, the second chemical treatment solution was directly replaced with a deionized water rinse solution having an oxygen content of less than about 100 ppb. After rinsing, the wafers were dried according to the process used in Comparative Examples 1-3.

Two additional batches of wafers were processed in the manner described above using a total of 3 rounds.

Three wafers from each lot were analyzed for particulate contamination ranging in size from 18 microns to 400 microns using 6 mm edge exclusion. The average results are shown in Table 2. Example 5 - Treatment with a solution containing copper followed by a solution containing HF

The treatment process of Comparative Example 4 was repeated except that the composition content of H ₂ O:NH ₄ OH:surfactant in the first chemical treatment liquid was 100:2.2:0.6 by volume.

Two additional batches of wafers were processed in the manner described above using a total of 3 rounds.

Three wafers from each lot were analyzed for particulate contamination ranging in size from 18 microns to 400 microns using 6 mm edge exclusion. The average results are shown in Table 2.

Table 2: Particles removed example Average LPD Number ¹ before processing after treatment difference Clearance percentage Comparative example 1 11841 1984 -9857 83 Comparative example 2 10002 1951 -8051 80 Comparative example 3 2115 291 -1824 86 Comparative example 4 10002 1943 -8059 81 Example 5 5334 3 -5331 99.9

¹ Average number of defective light spots

The data in Table 2 represent the average of the number of particles detected on 3 disks. The "Before" column lists the average number of particles on the wafer before wet processing, the "After" column lists the average number of particles on the wafer after wet processing, and the "Difference" column lists the wet processing. The average difference in particles on the wafer between pre-processing and post-wet processing. A negative "Difference" indicates the number of particles removed during wet processing. The "Percent Removal" column lists the average percentage of particles that were removed based on the number of particles on the wafer prior to the wet processing process.

The data in Table 2 demonstrate that the method of the present invention is effective in reducing contaminant particles during wet processing of copper-containing electronic components. For example, in Example 5, 99.9% of the particles were removed by exposing the copper-containing electronic components to the SC1 solution followed by exposing the wafer to a solution containing hydrofluoric and hydrochloric acids. These results are surprising and unimaginable when compared to comparative examples. For example, when a copper-containing disc is exposed to SC1 solution (Comparative Example 1), ammonium hydroxide solution (Comparative Example 2), hydrofluoric acid/hydrochloric acid solution (Comparative Example 3) or after ammonium hydroxide to hydrofluoric acid/hydrochloric acid The combination of solutions (Comparative Example 4) had a particle removal percentage not higher than 86%. These results are schematically shown in FIG. 1 . FIG. 1 shows a bar graph of the percentage of removed particles according to Comparative Examples 1 to 4 and Example 5. FIG. As can be seen in Figure 1, the copper-containing wafers treated according to the method of the present invention were unexpectedly better than those of Comparative Examples 1-4.

Although the invention has been described in terms of certain preferred embodiments, it will be apparent that various changes and modifications to those preferred embodiments will be apparent to those skilled in the art. The above descriptions are only illustrative of the present invention and not limiting.

Claims (20)

1. method that the electronic devices and components with copper containing surfaces are carried out wet processing, this method comprises:

(a) make the surface of electronic devices and components contact copper oxidation liquid in first duration of contact; And

(b) subsequently, make the surperficial contact etch liquid of electronic devices and components in second duration of contact, wherein to keep water pH value be 5 or lower and contain etching reagent and be less than 5 to etching solution, the dissolved oxygen of 000ppb or suspension oxygen, and wherein the surface of electronic devices and components contacts with etching solution and pollutant can be removed from the surface of electronic devices and components with copper oxidation liquid.

2. method according to claim 1, wherein copper oxidation liquid comprises the oxygenant of selecting from the group of being made up of hydrogen peroxide, ozone, ferric cyanide or their combination.

3. method according to claim 2, wherein selective oxidation agent from the group of forming by hydrogen peroxide, ozone or their combination.

4. method according to claim 3, wherein copper oxidation liquid comprise water, according to the cumulative volume of copper oxidation liquid hydrogen peroxide at least about 0.1 volume percent, and to keep the pH value be 7 or bigger.

5. method according to claim 1, wherein copper oxidation liquid comprises water, hydrogen peroxide and ammonium hydroxide.

6. method according to claim 5, wherein copper oxidation liquid contains water, hydrogen peroxide and ammonium hydroxide, volume ratio H ₂O: H ₂O ₂: NH ₄OH is between about 5: 1: 1 to about 200: 1: 1.

7. method according to claim 1 is wherein selected etching reagent from the group of being made of hydrochloric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, acetate, citric acid, tartrate and their combination.

8. method according to claim 1, wherein etching solution is the solution that contains hydrofluoric acid, the solution that contains hydrofluoric acid comprises hydrofluoric acid and deionized water, volume ratio H ₂O: HF is between about 5: 1 to about 1000: 1.

9. it is 3 or lower that method according to claim 8, the pH value that wherein contains the solution of hydrofluoric acid are maintained at about.

10. method according to claim 9, the solution that wherein contains hydrofluoric acid further comprises hydrochloric acid, volume ratio H ₂O: HF: HCl is between about 50: 1: 1 to about 1000: 1: 1.

11. method according to claim 10, the solution that wherein contains hydrofluoric acid comprises dissolved oxygen or the suspension oxygen of about 100ppb at least.

12. method according to claim 1 wherein after making electronic devices and components contacts copper oxidation liquid, and before making electronic devices and components contact etch liquid, is utilized to comprise that the washing fluid of deionized water washes electronic devices and components.

13. method according to claim 1, wherein one of copper oxidation liquid or etching solution comprise tensio-active agent, inhibitor or their combination at least.

14. method according to claim 1 is wherein carried out wet processing to electronic devices and components in one or more containers.

15. method according to claim 1 is wherein handled electronic devices and components in single container.

16. method according to claim 15 wherein behind electronic devices and components contact copper oxidation liquid, is directly replaced copper oxidation liquid with washing fluid or etching solution.

17. method according to claim 1, wherein the pH value of copper oxidation liquid is at least about 7 or higher.

18. the method that the electronic devices and components with copper containing surfaces are carried out wet processing, this method comprises:

(a) one or more electronic devices and components with copper containing surfaces are placed in single container;

(b) the copper oxidation liquid that will comprise oxygenant injects in the container;

(c) make electronic devices and components contact copper oxidation liquid in first duration of contact, in container, discharge copper oxidation liquid then;

(d) with the pH value be 5 or hydrofluoric acid containing solution lower, that have 5000ppb dissolved oxygen or suspension oxygen at least inject in the container; And

(e) make electronic devices and components connect hydrofluoric acid containing solution in second duration of contact, discharge hydrofluoric acid containing solution then from container, wherein the surface of electronic devices and components contact copper oxidation liquid and hydrofluoric acid containing solution can be removed pollutant from the surface of electronic devices and components.

19. method according to claim 18 wherein by utilizing another kind of treatment solution to replace, is discharged copper oxidation liquid and hydrofluoric acid containing solution in container.

20. the method that the electronic devices and components with copper containing surfaces are carried out wet processing, this method comprises:

(a) make the surface of electronic devices and components contact copper oxidation liquid in first duration of contact, wherein the pH value of copper oxidation liquid is at least about 7 or higher; And

(b) subsequently, make the surperficial contact etch liquid of electronic devices and components in second duration of contact, wherein to keep water pH value be 5 or lower and contain etching reagent and be less than 5 to etching solution, the dissolved oxygen of 000ppb or suspension oxygen or other copper oxidant, and wherein the surface of electronic devices and components contacts with etching solution and pollutant can be removed from the surface of electronic devices and components with copper oxidation liquid.

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