CMP slurry reuse optimization system through convergence and complex processing technology

Abstract

The present invention relates to the construction of an optimized system for reusing CMP slurry through convergence processing technology. The CMP slurry reuse system of the present invention comprises: a slurry collection unit (100) for collecting a slurry containing high concentrations of abrasive particles and chemicals among waste slurries discarded after CMP; a fine particle separation unit (200) for dispersing fine particles on the surface of abrasive particles of the waste slurry collected from the slurry collection unit; an abrasive particle uniformity unit (300) for inserting electrodes into both ends of the waste slurry from which fine particles have been separated in the fine particle separation unit (200) and applying an electric field to ensure uniformity of the shape and size of the abrasive particles and remove impurities; a filter unit (600) for extracting abrasive particles and chemicals and ultrapure water from the slurry extracted from the abrasive particle uniformity unit (300); and an abrasive particle and chemical mixing unit (600) for remixing the abrasive particles and high concentration chemicals extracted from the filter unit (600).

Description

Technology Field

[0001] The present invention relates to a system for the regeneration and reuse of slurry abrasives in a Chemical Mechanical Polishing (CMP) device, and to an advanced technology for selectively recovering specific particles and removing contaminants from waste slurry discharged in large quantities after a Chemical Mechanical Polishing (CMP) process in which a slurry is flowed over the surface of a wafer to form a flattened insulating layer or metal wiring to form a micro semiconductor circuit. Background Technology

[0002] Generally, methods for treating waste slurry generated in the CMP (Chemical Mechanical Polishing) process include purification treatment using water treatment chemicals, treatment by solidifying the waste slurry, and regeneration treatment by purifying effective abrasive particles or chemicals within the slurry.

[0003] The purification method using the aforementioned water treatment chemicals removes pollutants through appropriate chemical treatment using slaked lime (Ca(OH)2), sulfuric acid (H2SO4), and polymers (coagulant aids), and then discharges the resulting solution into rivers in accordance with legal discharge standards after dilution with deionized water (DI Water); however, this chemical treatment process leads to an increase in diluted wastewater due to the large-scale use of DI Water, and causes problems such as increased costs resulting from the expansion of additional wastewater storage and treatment facilities.

[0004] Furthermore, the solidification treatment of waste slurry can have a significant impact on the ecosystem if the solidified material contains particles such as silica (SiO2) and alumina, as well as hazardous substances like heavy metals; additionally, it presents problems that may pose health and safety risks to workers due to its chemical composition.

[0005] To solve the problems of treatment costs and environmental issues associated with wastewater treatment of waste slurry, a regeneration treatment method can be used to obtain pure slurry by removing contaminants from the waste slurry generated after the Chemical Mechanical Polishing (CMP) process.

[0006] Various technologies for removing contaminants through a purification process to purify effective abrasive particles or chemicals within waste slurry for reuse in the process have been presented in the prior art.

[0007] Conventional regenerated slurry systems have the disadvantage that, in terms of the technology for capturing waste slurry, there is an excessive influx of pollutants, which necessitates securing space for collection and water tanks, and simultaneously causes additional factors such as wastewater treatment time and costs.

[0008] Furthermore, due to the nature of waste slurry, it may contain various contaminants, and if these contaminants are not removed, they can affect the process. Currently, technologies for separating fine particles within waste slurry suffer from a disadvantage of reduced treatment efficiency due to technical limitations; the separation technique using agitators to separate fine abrasive particles from contaminants is limited to removing suspended solids through simple sedimentation and settling.

[0009] Furthermore, there is a disadvantage in that market demand is low due to a rejection of the product caused by a lack of market awareness regarding recycled slurry and a lack of trust in its quality. Prior art literature

[0010] Korean Registered Patent 10-1078818 (October 26, 2011) Korean Published Patent 10-2023-0001382 (January 4, 2023) U.S. Registered Patent 8387902 B2 (March 5, 2013) The problem to be solved

[0011] The present invention was developed to solve the above problems and aims to provide a system for optimizing CMP slurry reuse through fusion composite processing technology.

[0012] In other words, we aim to provide a slurry reuse system by developing advanced technology that selectively recovers specific particles within waste slurry and removes contaminants. means of solving the problem

[0013] The CMP slurry reuse system of the present invention, aimed at solving the above problem, comprises: a slurry collection unit (100) for collecting a slurry containing high concentrations of abrasive particles and chemicals among waste slurries discarded after CMP; a fine particle separation unit (200) for dispersing fine particles on the surface of abrasive particles of the waste slurry collected from the slurry collection unit (100); an abrasive particle uniformity unit (300) that proceeds simultaneously with the fine particle separation unit (200), inserts electrodes and applies an electric field to ensure uniformity of the shape and size of the abrasive particles and removes impurities so that only uniform particles can be decomposed by an electrochemical reaction; a slurry mixing unit (400) for mixing the slurry that has undergone the processes of the fine particle separation unit (200) and the abrasive particle uniformity unit (300); a filter unit (500) for extracting abrasive particles, chemicals, and ultrapure water from the slurry extracted from the abrasive particle uniformity unit (300); and the slurry extracted from the filter unit (500). It consists of an abrasive particle and chemical remixing unit (600) that remixes abrasive particles and a high-concentration chemical. Effects of the invention

[0014] The slurry reuse system according to the present invention can reduce sludge and wastewater used in the production process by reusing chemical raw materials and ultrapure water, and has the effect of reducing smoke that may be generated during slurry transportation or chemicals used in wastewater treatment.

[0015] In addition, since the recycled slurry is supplied directly to the production process without designated space or logistics distance, it can be used without sedimentation, and abrasive particles and chemicals from impurities can be obtained and ultrapure water extracted from the mixture for recycling. Brief explanation of the drawing

[0016] FIG. 1 is a diagram illustrating the process of a CMP slurry regeneration system according to the present invention. FIG. 2 is a drawing illustrating a slurry collection section during the process of a CMP slurry regeneration system according to the present invention. FIG. 3 is a diagram illustrating the fine particle separation section, the polishing particle uniformity section, and the slurry mixing section during the process of the CMP slurry regeneration system according to the present invention. FIG. 4 is a diagram illustrating the filter section during the process of the CMP slurry regeneration system according to the present invention. FIG. 5 is a diagram illustrating the remixing of abrasive particles and chemicals during the process of the CMP slurry regeneration system according to the present invention. Specific details for implementing the invention

[0017] The present invention is capable of various modifications and may take various forms, and embodiments (aspects or examples) are to be described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0018] The terms used in this specification are used merely to describe specific embodiments (aspects or examples) and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “consisting of” are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0019] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0020] The terms "~1~," "~2~," etc., described in this specification are used merely to distinguish different components and are not bound by the order of manufacture; furthermore, the names may not match those in the detailed description of the invention and the claims.

[0021] The Chemical Mechanical Polishing (CMP) process is a semiconductor miniaturization process that forms a flattened insulating layer or metal wiring by flowing a CMP slurry over the wafer surface to form a fine semiconductor circuit.

[0022] The slurry that flows onto the wafer surface consists of an abrasive and ultrapure water (DI Water) for flattening the wafer, and depending on the type of semiconductor film to be polished, it includes additives such as a dispersant, an oxidizing agent, a pH adjusting solution, and a corrosion inhibitor to stabilize the particles.

[0023] Abrasives are abrasive particles that perform polishing operations to remove films; they must maintain dispersibility and polishing volume, and possess appropriate hardness to minimize scratches on the wafer surface.

[0024] DI water plays a role in transporting abrasives and acting as a lubricant to prevent scratches caused by the abrasives. It also moves residues generated during the CMP process and regulates the heat produced during polishing.

[0025] Additives amplify the slurry effect and add additional necessary functions depending on the characteristics of the material being polished; representative examples include defoaming agents (foam suppression), corrosion inhibitors, and pH adjusting solutions.

[0026] The slurry reuse optimization system of the present invention comprises: a slurry collection unit (100) for selectively collecting high-concentration waste slurry among waste slurries discharged after a Chemical Mechanical Polishing (CMP) process; a fine particle separation unit (200) for separating fine particles by applying high-frequency sound waves between abrasive particles of the high-concentration waste slurry collected in the waste slurry collection unit (100); an abrasive particle uniformity unit (300) that proceeds simultaneously with the fine particle separation unit (200), inserts electrodes and applies an electric field to decompose only uniform particles by electrochemical reaction to ensure uniformity of the shape and size of the abrasive particles and remove impurities; a slurry mixing unit (400) for mixing the slurry that has undergone the processes of the fine particle separation unit (200) and the abrasive particle uniformity unit (300); a filter unit (500) for extracting abrasive particles, chemicals, and ultrapure water from the slurry mixed in the slurry mixing unit (400); and the It consists of an abrasive particle and chemical remixing unit (600) that remixes abrasive particles extracted from a filter unit (500) with a high-concentration chemical.

[0027] First, in the waste slurry collection unit (100), the concentration of abrasive particles and chemical concentration in the waste slurry discharged after the CMP process is measured in real time through a specific gravity meter (102).

[0028] The above specific gravity meter (102) is a device that measures the concentration of abrasive particles and chemical concentration in waste slurry in real time, and the measured specific gravity value is transmitted to a three-way control valve (104) and an automatic opening / closing control device (103).

[0029] If the concentration of abrasive particles and chemical concentration in the waste slurry measured by the above specific gravity meter (102) is low, the three-way control valve (104) is connected to the wastewater treatment path (105), and if the concentration of abrasive particles and chemical concentration is high, the three-way control valve (103) is connected to the reuse path (106).

[0030] In addition, automatic control system monitoring is implemented to selectively select and collect waste slurry by including an automatic opening and closing control device (103) that automatically controls the specific gravity meter (102) and the three-way control valve (104) in real time.

[0031] In the above-mentioned fine particle separation unit (200), high-frequency sound waves are applied to the high-concentration waste slurry collected from the above-mentioned slurry collection unit (100) through an ultrasonic generator (203).

[0032] The high-concentration waste slurry collected from the above slurry collection unit (100) contains a large amount of abrasive particles along with various impurities and contaminants.

[0033] If various impurities and contaminants contained in high-concentration waste slurry are not removed, scratches may form on the wafer surface, which can directly affect semiconductor quality and reduce production yield.

[0034] High-frequency sound waves are applied between the abrasive particles in the waste slurry through the above-mentioned ultrasonic generator (203) to disperse the fine particles (202), which are contaminants attached to the surface of the abrasive particles, thereby preventing aggregation.

[0035] In the above-mentioned fine particle separation unit (200), fine particles (202), which are contaminants attached to the surface of abrasive particles in the waste slurry, are dispersed to prevent aggregation, and in the above-mentioned abrasive particle uniformity unit (300), abrasive particles and contaminants or impurities are separated through a mesh filter (301), an internal separation membrane (304), and an electric field to ensure uniform abrasive particles without deformation of the shape and size of the abrasive particles.

[0036] In the above-mentioned abrasive particle uniform section (300), electrodes are inserted at both ends of the waste slurry, and when an electric field is applied, the abrasive particles and contaminants move to opposite poles.

[0037] Generally, the abrasive particles used in the CMP process have a negative charge (-) and move toward the positive electrode when an electric field is applied, and contaminants generated in the CMP process have a positive charge (+) and move toward the negative electrode.

[0038] The above mesh filter (301) serves to filter out impurities while maintaining the size and shape of the abrasive particles, thereby enabling the abrasive particles to be kept uniform.

[0039] The above internal separator (304) is a key element for increasing the separation efficiency of particles in an electric field, and forms a boundary so that particles with different polarities can be reliably separated when an electric field is applied, thereby allowing for more fine separation of abrasive particles and contaminants.

[0040] Afterwards, the slurry mixing section (400) mixes the slurry that has undergone the processes of the fine particle separation section (200) and the abrasive particle uniformity section (300).

[0041] The above filter unit (500) is composed of a first filter unit consisting of an ultrafiltration membrane (504) and an ultrafiltration pump (503), and a second filter unit consisting of a reverse osmosis membrane (506) and a reverse osmosis pump (505).

[0042] The above-mentioned ultrafiltration pump (503) serves to pass the waste slurry through the ultrafiltration membrane (504) at a constant pressure, thereby enabling effective filtering of fine particles within the slurry.

[0043] The above ultrafiltration membrane (504) is a filter capable of removing fine particles of 0.01 to 0.1 μm in size, and separates abrasive particles, chemicals, and ultrapure water in the first stage.

[0044] The above reverse osmosis pump (505) is a device that applies high pressure to pass waste slurry through a reverse osmosis membrane (506) and moves chemicals and ultrapure water separated in the first filter section to the reverse osmosis membrane (506).

[0045] The above reverse osmosis membrane (506) is an ultrafine filter with a size of 0.0001 to 0.001 μm that separates and extracts high concentration chemicals and ultrapure water.

[0046] The high-concentration chemical extracted here is mixed with the abrasive particles extracted from the first filter section to make a regeneration slurry, and the ultrapure water is used as recycled water.

[0047] In the above-mentioned abrasive particle and chemical mixing section (600), a regenerated slurry (602) mixed with abrasive particles extracted from the first filter section and a high-concentration chemical extracted from the second filter section, a new chemical (601) for maintaining the optimal chemical composition of the slurry, and a slurry system (603) for controlling the viscosity, pH, particle distribution, etc. of the slurry are introduced and stirred to produce a slurry that can be reused in the CMP process.

[0048] According to an embodiment of the present invention, the process may be divided into additional steps or combined into fewer steps. Additionally, some steps may be omitted as necessary, and the order of the steps may be changed.

[0049] The present invention, as described above with reference to the attached drawings, is susceptible to various modifications and alterations by a person skilled in the art, and such modifications and alterations not limited by the claims should be interpreted as being included within the scope of the rights of the present invention. Explanation of the symbols

[0050] 100: Slurry collection unit 101: Slurry 102: Specific gravity meter 103: Automatic opening / closing control device 104: 3-way control valve 105: Wastewater treatment path 106: Reuse path 200: Fine particle separation unit 201: Ultrasonic processor 202: Microparticles 203: Ultrasonic generator 300: Abrasive particle uniform section 301: Mesh filter 302: Impurity particles 303: Abrasive particles 304: Internal separator 400: Slurry mixing section 500: Filter section 501: Motor 502: Tank 503: Ultrafiltration pump 504: Ultrafiltration membrane 505: Reverse osmosis pump 506: Reverse osmosis membrane 507: Abrasive particle extraction furnace 508: Chemical extraction furnace 509: Ultrapure water extraction furnace 510: Chemical and ultrapure water mixing furnace 511: Slurry Regeneration Furnace 600: Abrasive Particle and Chemical Remixing Section 601: New Chemical 602: Regenerated Slurry 603: Slurry System 604: Stirring Tank 605: Stirrer magnet

Claims

Claim 1 A slurry collection unit (100) for selectively collecting high-concentration slurry among waste slurries discharged after the CMP process; a fine particle separation unit (200) for removing fine particles by applying high-frequency sound waves between the abrasive particles of the high-concentration slurry collected in the slurry collection unit (100); an abrasive particle uniformity unit (300) that proceeds simultaneously with the fine particle separation unit (200), inserts electrodes and applies an electric field to ensure uniformity of the shape and size of the abrasive particles and remove impurities so that only uniform particles can be decomposed by an electrochemical reaction; a slurry mixing unit (400) for mixing the slurry that has undergone the processes of the fine particle separation unit (200) and the abrasive particle uniformity unit (300); a filter unit (500) for extracting abrasive particles, chemicals, and ultrapure water from the slurry mixed in the slurry mixing unit (400); and abrasive particles and chemicals that remix the abrasive particles and chemicals extracted in the filter unit (500). A slurry reuse system through a composite processing technology including a chemical remixing unit (600). Claim 2 A slurry reuse system through a convergence processing technology according to claim 1, wherein the slurry collection unit (100) includes a specific gravity meter (102) for measuring the specific gravity of waste slurry. Claim 3 A slurry reuse system through a convergence treatment technology according to claim 2, wherein the slurry collection unit (100) includes a three-way control valve (104) that receives a signal from the specific gravity meter and classifies the waste slurry into a wastewater treatment path (105) and a reuse path (106). Claim 4 A slurry reuse system through convergence processing technology according to claim 3, wherein the slurry collection unit (100) includes an automatic opening and closing control device (102) capable of real-time automatic control by linking the specific gravity measuring instrument (102) and the three-way control valve (104) to implement automatic control system monitoring. Claim 5 A slurry reuse system through a convergence treatment technology according to claim 3, characterized in that a low-concentration slurry containing a small amount of abrasive particles is discharged into the wastewater treatment path, and a high-concentration slurry containing a large amount of abrasive particles is discharged into the reuse path. Claim 6 A slurry reuse system through a convergence processing technology according to claim 1, wherein the microparticle separation unit (200) includes an ultrasonic generator (203) capable of generating high-frequency sound waves. Claim 7 A slurry reuse system through a composite processing technology according to claim 1, wherein the abrasive particle uniformity section (300) includes a mesh filter (301) that filters out impurities while maintaining the shape and size of the abrasive particles uniformly. Claim 8 A slurry reuse system through a composite processing technology according to claim 7, wherein the abrasive particle uniform portion (300) further comprises an internal separation membrane (304) that increases the separation efficiency of particles in an electric field. Claim 9 A slurry reuse system through a composite processing technology according to claim 1, wherein the filter unit (500) comprises a first filter unit composed of an ultrafiltration pump (503) and an ultrafiltration membrane (504). Claim 10 A slurry reuse system through a convergence processing technology according to claim 9, wherein the filter unit (500) further comprises a second filter unit composed of a reverse osmosis pump (505) and a reverse osmosis membrane (506). Claim 11 A slurry reuse system through a composite processing technology according to claim 9 or claim 10, wherein the first filter section filters the slurry extracted from the abrasive particle uniform section (300) with an ultrafiltration membrane (604) to extract abrasive particles and chemicals. Claim 12 A slurry reuse system through a convergence treatment technology according to claim 10, wherein the second filter unit re-filters the chemical extracted from the first filter unit using a reverse osmosis membrane (506) to extract high-concentration chemicals and ultrapure water. Claim 13 A slurry reuse system through a convergence processing technology according to claim 10, characterized by mixing abrasive particles extracted from the first filter unit and a high-concentration chemical extracted from the second filter unit to create a regenerated slurry. Claim 14 A slurry reuse system through a fusion processing technology according to claim 10, wherein the abrasive particle and chemical remixing unit (600) is characterized by recomposing the chemical composition ratio by introducing a regenerated slurry (602) made by mixing abrasive particles extracted from the first filter unit and a high-concentration chemical extracted from the second filter unit, a new chemical (601), and a slurry system (603).

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