Cleaning process for improving surface quality of wafer

Abstract

The invention relates to the field of semiconductor cleaning, and discloses a cleaning process for improving the surface quality of a wafer, which comprises the steps of wafer pre-cleaning and wafer terminal cleaning, in the wafer pre-cleaning step, the wafer is sequentially subjected to first organic solution cleaning, pure water ultrasonic cleaning, mechanical scrubbing and second organic solution cleaning; and in the wafer terminal cleaning step, the wafer is sequentially subjected to organic emulsion solution cleaning, SPM cleaning, HQDR cleaning, high-concentration SC1 cleaning, QDR cleaning, SC2 cleaning, DHF cleaning, low-concentration SC1 cleaning, ozone water combined cleaning and spin-drying. According to the method, the cleaning process is integrated and optimized from the cleaning mechanism, the pertinence is higher, the cleaning process is more complete, the method has the advantages of being better in particulate matter cleaning effect, more thorough in stubborn pollutant removal, bidirectional in microstructure protection and the like, the wafer quality is greatly improved, operation is easy and convenient to implement, the cleaning cost is effectively reduced, and the method has good popularization prospects.

Description

Technical Field

[0001] This invention relates to the field of semiconductor cleaning, and more specifically to a cleaning process for improving the surface quality of wafers. Background Technology

[0002] In semiconductor manufacturing, wafer surface cleaning is a critical step in ensuring device performance and yield. Cleaning processes are integrated into every stage of wafer manufacturing. After each process step, different types of contaminants remain on the wafer surface, such as particulate matter, organic matter, metal ions, and oxide layers. These contaminants can affect the stability of subsequent processes and the quality of the finished product, thus requiring high-quality cleaning. From the perspective of cleaning mechanisms, these mainly include: chemical cleaning mechanisms—acid-base neutralization, redox reactions, complexation reactions, etc.; physical cleaning mechanisms—cavitation effect of ultrasonic cleaning, mechanical brushing, active particle bombardment of plasma cleaning, etc.; and combined physical and chemical cleaning—Megasonic cleaning, etc. From the perspective of cutting-edge technologies and process development, these mainly include: monolayer cleaning technology—self-assembled monolayers (SAMs), etc.; low-damage cleaning technology—low-temperature plasma cleaning, supercritical CO2 cleaning, etc.; and nanomaterial-assisted cleaning—nanoparticle cleaning, photocatalytic nanomaterials, etc. However, existing single processes cannot effectively improve wafer surface quality, and the mainstream RCA wet chemical cleaning process also has certain limitations in its wafer cleaning capabilities. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a cleaning process for improving wafer surface quality, the technical solution of which is as follows: A cleaning process for improving the surface quality of wafers includes the following steps: (1) Wafer pre-cleaning ① First organic solution cleaning: The mechanically polished wafer is ultrasonically cleaned with a first organic solution; the first organic solution includes surfactants, alkanolamines, chelating agents, penetrants and water; ② Pure water ultrasonic cleaning: ultrasonic frequency is 55-80KHz, cleaning time is 5-20min; ③ Mechanical brushing: Use a brush to wipe the non-use surface and the use surface of the wafer separately; ④ Second organic solution cleaning: The second organic solution includes surfactants, chelating agents, penetrants, and water; ultrasonic cleaning; (2) Chip terminal cleaning ① Cleaning with organic emulsion solutions: Organic emulsion solutions include surfactants and water; ultrasonic cleaning; ②SPM cleaning: The volume ratio of H2SO4 to H2O2 in the cleaning solution is (5.1-9.9):1; ③HQDR cleaning: Cleaning temperature is 45-75℃, and cleaning time is 4-20 minutes; ④ High-concentration SC1 cleaning: The volume ratio of NH4OH, H2O2, and H2O in the cleaning solution is 1:(0.5-2.3):(4.2-7.5); megasonic cleaning; ⑤QDR cleaning: Cleaning temperature is room temperature, and the cleaning time is 4-20 minutes; ⑥SC2 cleaning: The volume ratio of HCl, H2O2 and H2O in the cleaning solution is 1:(0.5-2.5):(7.5-12.5); ⑦ DHF cleaning: The volume ratio of HF to H2O in the cleaning solution is 1:(7.5-20.5). ⑧ Low-concentration SC1 cleaning: The volume ratio of NH4OH, H2O2, and H2O in the cleaning solution is 1:(0.5-2.5):(8-23); megasonic cleaning; ⑨ Ozone water combination cleaning: including DI-O3 cleaning, NH4OH-H2O cleaning and DHF cleaning; ⑩ Spin-drying: The temperature is 25-75℃, the time is 4-12min, the wafer is in a centrifugal rotation state, and the speed is 500-2300r / min.

[0004] Furthermore, in step (1) ① the reagent of the first organic solution, the surfactant is selected from one or more of fatty acid methyl ester ethoxylate (FMEE), fatty acid methyl ester ethoxylate sulfonate (FMES), fatty alcohol polyoxyethylene ether (AEO-9), dodecylphenol polyoxyethylene ether (OP-10), polyvinylpyrrolidone (PVP), propylene glycol methyl ether acetate (PMA), and N-methylpyrrolidone (NMP); the alkanolamine is selected from one of N-methyldiethanolamine (MDEA) and triethanolamine (TEA). One or more chelating agents are selected from sodium citrate (Na3C6H5O7), tetrasodium ethylenediaminetetraacetate (EDTA-4Na), disodium ethylenediaminetetraacetate (EDTA-2Na), nano-sized sodium silicate (Na2SiO3), and nano-sized potassium silicate (K2SiO3); the penetrant is selected from p-methoxy fatty amide benzenesulfonic acid, nonylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; the cleaning temperature is 25-55℃, the cleaning time is 5-25min, and the ultrasonic frequency is 25-55KHz.

[0005] Furthermore, in step (1) ① the first organic solution, the mass percentages of fatty acid methyl ester ethoxylate sulfonate (FMES), N-methylpyrrolidone (NMP), N-methyldiethanolamine (MDEA), sodium silicate (Na2SiO3), polyvinylpyrrolidone (PVP), and fatty alcohol polyoxyethylene ether are 2%-5%, 10%-15%, 3%-5%, 1%-3%, 0.5%-1%, and 2%-5%, respectively, which are made up to 100% by water. The reagents are industrial grade, and the water is ultrapure water. The cleaning temperature is 30-40℃, the cleaning time is 10-20 min, and the ultrasonic frequency is 30-45KHz.

[0006] Furthermore, in the reagents of the second organic solution in step (1) ④, the surfactant is selected from one or more of methyl vinyl ether-maleic anhydride copolymer (PVM / MA), fatty alcohol amine ethoxylate, and maleic anhydride alcohol amine copolymer; the chelating agent is selected from one or more of sodium citrate (Na3C6H5O7), tetrasodium ethylenediaminetetraacetate (EDTA-4Na), disodium ethylenediaminetetraacetate (EDTA-2Na), nano-sized sodium silicate (Na2SiO3), and nano-sized potassium silicate (K2SiO3); the penetrant is selected from one or more of p-methoxy fatty amide benzenesulfonic acid, nonylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; the cleaning temperature is 25-55℃, the cleaning time is 5-25min, and the ultrasonic frequency is 25-55KHz.

[0007] Furthermore, in step (1) ④, the mass percentages of the second organic solution are 1%-3%, 0.5%-1%, 0.1%-0.5%, 0.5%-2%, 2%-5%, and 1%-3%, respectively, of methyl vinyl ether-maleic anhydride copolymer (PVM / MA), sodium citrate (Na3C6H5O7), tetrasodium ethylenediaminetetraacetate (EDTA-4Na), sodium silicate (Na2SiO3), fatty alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether, respectively, which are made up to 100% by water. The reagents are industrial grade, and the water is ultrapure water. The cleaning temperature is 40-55℃, the cleaning time is 10-20 min, and the ultrasonic frequency is 30-45 kHz.

[0008] Furthermore, step (2) ① the organic emulsifying cleaning surfactant includes sodium dodecyl sulfate (SLS, chemical formula C). 12 H 25 SO4Na), sodium dodecylbenzenesulfonate (SDBS, chemical formula C4Na), 18 H 29NaO3S), polyoxyethylene (10) nonylphenol ether (abbreviated as OP-10), polyoxyethylene-15-nonylphenol ether (abbreviated as OP-15), fatty acid methyl ester ethoxylate (abbreviated as FMES), polyvinylpyrrolidone (abbreviated as PVP, chemical formula C6H9NO)n), sodium octylbenzenesulfonate (C 14 H 21 One or more of SO3Na are used; the cleaning temperature is 25-55℃, the cleaning time is 5-25min, and the ultrasonic frequency is 25-55KHz.

[0009] Furthermore, in step (2) ① the organic emulsion cleaning solution, sodium dodecylbenzenesulfonate (SDBS, chemical formula C) is present. 18 H 29 The mass percentages of NaO3S, polyvinylpyrrolidone (PVP, chemical formula C6H9NO)n, polyoxyethylene (10) nonylphenol ether (OP-10), and fatty acid methyl ester ethoxylate (FMES) are 0.5%-2%, 0.1%-0.5%, 0.1%-1%, and 0.5%-2%, respectively, and are made up to 100% by water. The reagents are industrial grade, and the water is ultrapure water. The cleaning temperature is 45-55℃, the cleaning time is 5-15min, and the ultrasonic frequency is 30-45KHz.

[0010] Furthermore, in step (2) ② SPM cleaning: the mass concentration of H2SO4 reagent is 96%-98%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 80-120℃, and the cleaning time is 4-20min; in step (2) ⑥ SC2 cleaning: the mass concentration of HCl reagent is 36%-38%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 60-85℃, and the cleaning time is 4-20min; in step (2) ⑦ DHF cleaning: the mass concentration of HF reagent is 48%-49%, the cleaning temperature is 20-30℃, and the cleaning time is 3-12min.

[0011] Furthermore, in step (2) ④ high concentration SC1 cleaning and step (2) ⑧ low concentration SC1 cleaning: the mass concentration of H4OH reagent is 28%-30%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 65-90℃, the cleaning time is 4-20min; the megaphonic cleaning frequency is 800-1000KHz.

[0012] Furthermore, in step (2) ⑨ ozone water combined cleaning, the DI-O3 concentration is 15-45ppm, the humidity is ≤90%RH, the flow rate is 2.5-6.5L / min, the cleaning temperature is 15-40℃, and the cleaning time is 15-65s; the volume ratio of NH4OH-H2O is 1:(3.5-8.5), the mass concentration of NH4OH reagent is 28%-30%, the cleaning temperature is 25-60℃, and the cleaning time is 25-90s; in the DHF cleaning reagent, the volume ratio of HF and H2O is 1:(25-75), the mass concentration of HF reagent is 48%-49%, the cleaning temperature is 20-30℃, and the cleaning time is 25-90s.

[0013] Compared with the prior art, the present invention has the following main advantages: 1. This invention addresses severe surface contamination after chemical mechanical polishing (CMP) by integrating and optimizing the cleaning process from the perspective of cleaning mechanism. The reagent formulation design and cleaning process are more targeted, and the cleaning process is more complete. It features better particulate matter cleaning effect, more thorough removal of stubborn contaminants, and bidirectional protection of microstructure.

[0014] 2. This invention features targeted, step-by-step, cyclical treatment of wafer surface contaminants, reducing the residual amount of particles and metal ions, and significantly improving wafer quality. This invention prioritizes a pre-cleaning process. The first organic solution dissolves and removes organic contaminants such as wax from the wafer surface after chemical mechanical polishing (CMP). The second organic solution removes residual contaminants such as polishing fluid. Further surface contamination is removed through brushing and ultrasonic cleaning. A final cleaning process is employed. Organic emulsion cleaning removes organic and inorganic contaminants generated during testing or partially remaining on the wafer. An improved RCA wet cleaning process, tailored to the particle size of the contaminants, uses ultrasonic / megason frequencies to progressively remove particles and metal ions of different sizes. Ozone water combined cleaning specifically removes extremely fine adsorbed particles and residual metal ions. Ultimately, the wafer achieves high surface cleanliness and a large usable area.

[0015] 3. The cleaning method of the present invention is simple and easy to operate, effectively reduces cleaning costs, and has a good prospect for promotion. Attached Figure Description

[0016] Figure 1 , Figure 2 Images showing the results of wafer cleaning and testing (using a high-intensity light) provided in Embodiment 1 (pre-cleaning process) of the present invention. Figure 3 , Figure 4 Images showing the test results (equipment: Candela 8520) of particles ≥0.2μm after wafer cleaning provided by the method in Embodiment 1 (terminal cleaning process) of the present invention; Figure 5 , Figure 6 Images showing the results of wafer cleaning and testing (using a high-intensity light) provided in Embodiment 2 (pre-cleaning process) of the present invention; Figure 7 , Figure 8 Images showing the test results (equipment: Candela 8520) of particles ≥0.2μm after wafer cleaning provided by the method in Embodiment 2 (terminal cleaning process) of the present invention; Figure 9 , Figure 10 Images showing the results of wafer cleaning and testing (using a high-intensity light) provided in Embodiment 3 (pre-cleaning process) of the present invention. Figure 11 , Figure 12 Image showing the test results (equipment Candela 8520) of particles ≥0.2μm after wafer cleaning provided by the method in Embodiment 3 (terminal cleaning process) of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings; unless otherwise specified in the description, all are conventional technologies and will not be repeated.

[0018] The overall implementation scheme of this invention is first described as follows: A cleaning process for improving the surface quality of wafers includes the following steps: (1) Wafer pre-cleaning ① First Organic Solution Cleaning: The mechanically polished wafer is ultrasonically cleaned using a first organic solution. The first organic solution includes a surfactant, an alkanolamine, a chelating agent, a penetrant, and water. The surfactant in the first organic solution is selected from one or more of the following: fatty acid methyl ester ethoxylate (FMEE), fatty acid methyl ester ethoxylate sulfonate (FMES), fatty alcohol polyoxyethylene ether (AEO-9), dodecylphenol polyoxyethylene ether (OP-10), polyvinylpyrrolidone (PVP), propylene glycol methyl ether acetate (PMA), and N-methylpyrrolidone (NMP). The alkanolamine is selected from N-methyl... One or more of diethanolamine (MDEA) and triethanolamine (TEA); the chelating agent is selected from one or more of sodium citrate (Na3C6H5O7), tetrasodium ethylenediaminetetraacetate (EDTA-4Na), disodium ethylenediaminetetraacetate (EDTA-2Na), nano-sized sodium silicate (Na2SiO3), and nano-sized potassium silicate (K2SiO3); the penetrant is selected from one or more of p-methoxy fatty amide benzenesulfonic acid, nonylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; the cleaning temperature is 25-55℃, the cleaning time is 5-25min, and the ultrasonic frequency is 25-55KHz. Further optimization was performed. In the first organic solution, the mass percentages of fatty acid methyl ester ethoxylate sulfonate (FMES), N-methylpyrrolidone (NMP), N-methyldiethanolamine (MDEA), sodium silicate (Na2SiO3), polyvinylpyrrolidone (PVP), and fatty alcohol polyoxyethylene ether were 2%-5%, 10%-15%, 3%-5%, 1%-3%, 0.5%-1%, and 2%-5%, respectively, made up to 100% with water. Industrial-grade reagents and ultrapure water were used. The cleaning temperature was 30-40℃, the cleaning time was 10-20 min, and the ultrasonic frequency was 30-45 kHz. The optimal solution consisted of FMES, NMP, MDEA, Na2SiO3, PVP, fatty alcohol polyoxyethylene ether, and H2O, with mass percentages of 3%, 12%, 4%, 2%, 0.75%, 4%, and 74.25%, respectively; a cleaning temperature of 38℃ and a cleaning time of 40 kHz.

[0019] In the first organic solution, FMES is an effective anionic surfactant with excellent detergency and emulsifying properties, helping to break down and remove waxes and greases. Furthermore, FMES incorporates cyclic sulfonated end-cap structures at both ends of its molecular chain, giving it a three-dimensional molecular chain structure, resulting in better dispersibility and excellent anti-backfogging properties. NMP is a highly selective and stable polar solvent that effectively dissolves various organic substances, including waxes, greases, and other contaminants. MDEA is an organic amine that enhances the detergency of cleaning agents; its performance is further strengthened when used in combination with FMES and NMP. Nano-sized Na₂SiO₃ achieves a higher contact area in solution, improving its chelating effect and exhibiting excellent detergency, helping to break down stubborn stains and greases on wafer surfaces. Fatty alcohol polyoxyethylene ether is a nonionic surfactant, belonging to the oil-in-water emulsifier category. It can orient itself on the surface of the solution and significantly reduce surface tension, synergistically promoting the effective penetration of the active ingredients in the solution into waxy contaminants on the wafer surface.

[0020] In this invention, the wafer is preferably a silicon carbide wafer and / or a silicon wafer after chemical mechanical polishing (CMP). The cleaning water is ultrapure water with a resistivity of More preferred The optimal choice is The particle size in ultrapure water is preferably ≤350 particles / L for the 0.1-0.2μm range, ≤100 particles / L for the 0.2-0.5μm range, ≤50 particles / L for the 0.5-1.0μm range, and ≤20 particles / L for the >1.0μm range. The concentration of metal ions (Al, Sb, As, Ba, B, Cr, Ca, Cu, Fe, Pb, Li, Mg, Mn, Ni, K, Na, Sr, Sn, Ti, V, Zn) is preferably ≤0.01ppb. Organic solution cleaning is preferably performed by immersion ultrasonic cleaning, with the wafer completely submerged in the cleaning reagent. The wafer is then circulated and rinsed using a circulating pump, followed by bottom ultrasonic cleaning.

[0021] ② Pure water ultrasonic cleaning: After the first organic solution cleaning, the wafer is then ultrasonically cleaned with pure water to remove stubborn impurities and residual cleaning solution from the wafer surface. The preferred frequency of the pure water ultrasonic cleaning is 55-80KHz, more preferably 60-75KHz, and most preferably 75KHz; the preferred cleaning time is 5-20min, more preferably 7-15min, and most preferably 7min.

[0022] ③ Mechanical brushing: The non-use surface and the use surface of the wafer are wiped separately with a brush; the brush is one or more of polyvinyl alcohol (PVA), polyurethane, silicone, nylon, and animal hair, with PVA being the most preferred; before, during and after brushing, pure water is continuously sprayed and rinsed to accelerate the removal of dirt; the brushing path is a unidirectional movement that rotates on the wafer surface to the entire wafer surface.

[0023] ④ Second organic solution cleaning: The second organic solution includes surfactant, chelating agent, penetrant and water; ultrasonic cleaning; the surfactant in the second organic solution is selected from one or more of methyl vinyl ether-maleic anhydride copolymer (PVM / MA), fatty alcohol amine ethoxylate, and maleic anhydride alcohol amine copolymer; the chelating agent is selected from one or more of sodium citrate (Na3C6H5O7), tetrasodium ethylenediaminetetraacetate (EDTA-4Na), disodium ethylenediaminetetraacetate (EDTA-2Na), nano-sized sodium silicate (Na2SiO3), and nano-sized potassium silicate (K2SiO3); the penetrant is one or more of p-methoxy fatty amide benzenesulfonic acid, nonylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; the cleaning temperature is 25-55℃, the cleaning time is 5-25min, and the ultrasonic frequency is 25-55KHz. Furthermore, in the second organic solution, the mass percentages of methyl vinyl ether-maleic anhydride copolymer (PVM / MA), sodium citrate (Na3C6H5O7), tetrasodium ethylenediaminetetraacetate (EDTA-4Na), sodium silicate (Na2SiO3), fatty alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether are 1%-3%, 0.5%-1%, 0.1%-0.5%, 0.5%-2%, 2%-5%, and 1%-3%, respectively, and are made up to 100% by water. The reagents are industrial grade, and the water is ultrapure water. The cleaning temperature is 40-55℃, the cleaning time is 10-20 min, and the ultrasonic frequency is 30-45 kHz. The optimal solution is as follows: the mass percentages of VM / MA, Na3C6H5O7, EDTA-4Na, Na2SiO3, fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, and H2O are 2%, 0.8%, 0.3%, 1.5%, 4%, 2%, and 89.4%, respectively. The cleaning temperature is 55℃ and the cleaning time is 15 min.

[0024] The second organic solution primarily removes polishing fluid residue, and further removes abrasive particles (cerium oxide, aluminum oxide, silicon dioxide, etc.), organic matter (lubricants, dispersants, additives, etc.), metal ions (calcium, magnesium, aluminum, etc.), oxides, and hydroxides remaining on the wafer surface. The PVM / MA monomers in the second organic solution contain vinyl and ether groups, exhibiting flexibility and hydrophilicity. The monomers with acidic anhydride groups provide the copolymer with reactivity and adhesion, helping to suspend abrasive particles and prevent their redeposition. The Na3C6H5O7 chelating agent in the second organic solution is composed of three carboxyl groups (-COOH) from a citric acid molecule and sodium ions (Na+). + The Na3C6H5O7 ions, formed by the combination of Na and Na+, dissociate into sodium ions (Na+) in solution. + ) and citrate ions (C6H5O7 3- It can undergo complexation reactions with various metal ions to form stable complexes. EDTA-4Na is the sodium salt form of ethylenediaminetetraacetic acid (EDTA), in which all four carboxyl groups (-COOH) in the ethylenediaminetetraacetic acid molecule are replaced by sodium ions (Na+). + It can replace various metal ions (such as Ca) 2+ Mg 2+ Fe 3+ (etc.) to form stable soluble complexes. In the second organic solution penetrant, nonylphenol polyoxyethylene ether is a nonionic surfactant formed by the condensation of ethylene oxide and nonylphenol under the action of a catalyst, and fatty alcohol polyoxyethylene ether is an ether formed by the condensation of fatty alcohol and polyethylene glycol (PEG). Both are small molecule surfactants that can easily approach the matrix and adsorb between the matrix and the dirt. Together with nonionic and anionic surfactants, they achieve the effects of wetting, penetrating, emulsifying, and entraining dirt.

[0025] In this invention, after the wafer is cleaned by the pre-cleaning process, it is observed under a strong light that the surface is clear, without oil film, cleaning solution residue, polishing solution residue, large particles such as bright white spots, and water stains.

[0026] (2) Chip terminal cleaning ① Organic emulsion solution cleaning: The organic emulsion solution includes surfactants and water; ultrasonic cleaning; the surfactants used in organic emulsion cleaning include sodium dodecyl sulfate (SLS, chemical formula C60). 12 H 25 SO4Na), sodium dodecylbenzenesulfonate (SDBS, chemical formula C4Na), 18 H 29NaO3S), polyoxyethylene (10) nonylphenol ether (abbreviated as OP-10), polyoxyethylene-15-nonylphenol ether (abbreviated as OP-15), fatty acid methyl ester ethoxylate (abbreviated as FMES), polyvinylpyrrolidone (abbreviated as PVP, chemical formula C6H9NO)n), sodium octylbenzenesulfonate (C 14 H 21 One or more of the following (SO3Na); the cleaning temperature is 25-55℃, the cleaning time is 5-25 min, and the ultrasonic frequency is 25-55 kHz. Furthermore, the organic emulsified cleaning solution contains sodium dodecylbenzenesulfonate (SDBS, chemical formula C...). 18 H 29 The mass percentages of NaO3S, polyvinylpyrrolidone (PVP, chemical formula C6H9NO)n, polyoxyethylene (10) nonylphenol ether (OP-10), and fatty acid methyl ester ethoxylate (FMES) are 0.5%-2%, 0.1%-0.5%, 0.1%-1%, and 0.5%-2%, respectively, and are made up to 100% with water. Industrial grade reagents and ultrapure water are used. The cleaning temperature is 45-55℃, the cleaning time is 5-15 min, and the ultrasonic frequency is 30-45 kHz. Optimal solution: The mass percentages of SDBS, PVP, OP-10, FMES, and H2O are 1.5%, 0.3%, 0.5%, 1%, and 96.7%, respectively; the cleaning temperature is 50℃, the cleaning time is 10 min, and the ultrasonic frequency is 40 kHz.

[0027] ②SPM Cleaning: The volume ratio of H2SO4 to H2O2 in the cleaning solution is (5.1-9.9):1. Further, the mass concentration of H2SO4 is 96%-98%, the mass concentration of H2O2 is 30%-32%, the cleaning temperature is 80-120℃, and the cleaning time is 4-20 min. Even further, the volume ratio of H2SO4 to H2O2 is (7-9):1; the cleaning temperature is 90-100℃, and the cleaning time is 7-13 min. The optimal solution is: a volume ratio of H2SO4 to H2O2 of 9:1; a cleaning temperature of 93-97℃; and a cleaning time of 10 min.

[0028] SPM cleaning can achieve the oxidative decomposition of organic pollutants. Hydrogen peroxide decomposes under acidic conditions to generate oxygen and reactive oxygen species (such as hydroxyl radicals), which can effectively decompose organic pollutants. Sulfuric acid provides a strong acid environment, which helps stabilize the decomposition of hydrogen peroxide and enhances the effect of the oxidation reaction.

[0029] ③HQDR cleaning: The cleaning temperature is 45-75℃ and the cleaning time is 4-20min; more preferably, the cleaning temperature is 60-75℃ and the cleaning time is 5-10min; the most preferred is the cleaning temperature is 75℃ and the cleaning time is 8min.

[0030] HQDR cleaning involves functions such as heating, spraying, bubbling, rapid drainage, and overflow. Heating reduces the temperature difference between the wafer and water after SPM (Surface Purification Processing) to prevent wafer breakage due to large local temperature differences. Spraying uses high-pressure jets of ultrapure water to clean the wafer surface, removing particulate matter, loose contaminants, and cleaning residue. Bubbling introduces air bubbles into the ultrapure water to enhance the cleaning effect; the formation, collapse, and movement of these bubbles physically agitate the liquid, promoting the removal of surface contaminants. Rapid drainage quickly discharges the cleaning water to reduce the chance of contaminant re-adhesion. Overflow continuously replenishes the ultrapure water, maintaining its purity.

[0031] ④ High-concentration SC1 cleaning: The volume ratio of NH4OH, H2O2, and H2O in the cleaning solution is 1:(0.5-2.3):(4.2-7.5); the mass concentration of H4OH reagent is 28%-30%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 65-90℃, and the cleaning time is 4-20 min; the megaphonic cleaning frequency is 800-1000 kHz. More preferably: the volume ratio of NH4OH, H2O2, and H2O is 1:(0.5-1.5):(4.5-5.5); the cleaning temperature is 75-85℃, the cleaning time is 7-14 min; and the megaphonic cleaning frequency is 850-950 kHz. The optimal ratio is: the volume ratio of NH4OH, H2O2 and H2O is 1:(0.8-1.2):(4.8-5.3); the cleaning temperature is 85℃, the cleaning time is 10min, and the megaphonic cleaning frequency is 950KHz.

[0032] In high-concentration SC1 cleaning, NH4OH provides an alkaline environment that helps dissolve and disperse particulate matter. The alkalinity of ammonia causes surface particles to acquire a negative charge, repelling them and making them easier to rinse away. Megasonography further enhances the removal of small particles ranging from 0.1 to 0.3 μm. Hydrogen peroxide not only oxidizes organic matter but also forms a thin oxide layer (SiO2) on the wafer surface. This oxide layer protects and passivates the wafer surface, making it less susceptible to contamination during subsequent processing.

[0033] ⑤QDR cleaning: The cleaning temperature is room temperature, and the cleaning time is 4-20 minutes. QDR cleaning mainly involves impacting the particles after SC1 treatment and carrying them away with ultrapure water, while also removing the cleaning residue, which helps to further remove particles.

[0034] ⑥SC2 Cleaning: The volume ratio of HCl, H2O2, and H2O in the cleaning solution is 1:(0.5-2.5):(7.5-12.5); the mass concentration of HCl reagent is 36%-38%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 60-85℃, and the cleaning time is 4-20 min. More preferably: the volume ratio of HCl, H2O2, and H2O is 1:(0.8-1.2):(8-11.5); the cleaning temperature is 65-80℃, and the cleaning time is 4-10 min. Most preferably: the volume ratio of HCl, H2O2, and H2O is 1:(1:(9-10.5); the cleaning temperature is 65℃, and the cleaning time is 5 min.

[0035] The main function of hydrochloric acid in SC2 solution is to complex and dissolve metal ion contaminants on the wafer surface. Hydrochloric acid provides chloride ions (Cl... - ) and metal ions (such as Fe) 3+ Cu 2+ Hydrogen peroxide (etc.) forms soluble chloride complexes, thereby effectively removing these metal ions; under acidic conditions, hydrogen peroxide can decompose to generate highly reactive oxygen species with strong oxidizing power, and can also prevent dissolved metal ions from redepositing onto the wafer surface; hydrochloric acid and hydrogen peroxide can chemically strip particles attached to the wafer surface, especially particles that are chemically bonded to the surface.

[0036] ⑦ DHF cleaning: The volume ratio of HF to H2O in the cleaning solution is 1:(7.5-20.5); Step (2) ⑦ DHF cleaning: The mass concentration of HF reagent is 48%-49%, the cleaning temperature is 20-30℃, and the cleaning time is 3-12 min. More preferably: the volume ratio of HF to H2O is 1:(10-20); the cleaning time is 5-10 min. Most preferably: the volume ratio of HF to H2O is 1:(10-12); the cleaning time is 5 min.

[0037] DHF cleaning can: A. Remove oxide layers. A silicon oxide (SiO2) layer often forms on the surface of wafers, and DHF can effectively remove this oxide layer. B. Surface passivation. After removing the silicon oxide layer, hydrofluoric acid leaves a clean and oxide-free silicon surface; at this point, fluoride ions (F... -DHF may form Si-F bonds with the silicon surface, temporarily passivating the surface and preventing it from rapidly re-oxidizing in air. This passivation effect helps maintain surface cleanliness in subsequent processing steps. C. Removal of specific contaminants. DHF can remove not only silicon oxide but also certain metal ions and other contaminants, which may be removed by forming soluble fluorides with fluoride ions. D. Surface roughness control. DHF treatment can also be used to control the roughness of the wafer surface. By precisely controlling the concentration and treatment time of DHF, the chemical properties and physical morphology of the surface can be fine-tuned, laying a good foundation for subsequent epitaxial growth or other processing steps.

[0038] ⑧ Low-concentration SC1 cleaning: The volume ratio of NH4OH, H2O2, and H2O in the cleaning solution is 1:(0.5-2.5):(8-23); the mass concentration of H4OH reagent is 28%-30%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 65-90℃, and the cleaning time is 4-20 min; the megaphonic cleaning frequency is 800-1000 kHz. More preferably: the volume ratio of NH4OH, H2O2, and H2O is 1:(0.8-1.5):(15-23); the cleaning temperature is 75-90℃, and the cleaning time is 4-12 min. Most preferably: the volume ratio of NH4OH, H2O2, and H2O is 1:(0.8-1.2):20; the cleaning temperature is 85-90℃, and the cleaning time is 5 min.

[0039] ⑨ Ozone water combination cleaning: including DI-O3 cleaning, NH4OH-H2O cleaning and DHF cleaning.

[0040] The DI-O3 concentration is 15-45 ppm, the humidity is ≤90%RH, the flow rate is 2.5-6.5 L / min, the cleaning temperature is 15-40℃, and the cleaning time is 15-65 s. More preferably, the concentration is 25-40 ppm, the flow rate is 3.5-5.5 L / min, the cleaning temperature is 25-35℃, and the cleaning time is 25-40 s. Most preferably, the concentration is 30-35 ppm, the flow rate is 4.5-5.5 L / min, the cleaning temperature is 23-30℃, and the cleaning time is 35-40 s.

[0041] The volume ratio of NH4OH to H2O is 1:(3.5-8.5), the mass concentration of NH4OH reagent is 28%-30%, the washing temperature is 25-60℃, and the washing time is 25-90s. More preferably, the volume ratio of NH4OH to H2O is 1:(4-7), the washing temperature is 35-55℃, and the washing time is 40-65s. Most preferably, the volume ratio of NH4OH to H2O is 1:(5-6), the washing temperature is 40-50℃, and the washing time is 50-60s.

[0042] The DHF cleaning reagent has a volume ratio of HF to H₂O of 1:(25-75), an HF reagent concentration of 48%-49%, a cleaning temperature of 20-30℃, and a cleaning time of 25-90s. More preferably, the volume ratio of HF to H₂O is 1:(35-70), the cleaning temperature is 23-27℃, and the cleaning time is 40-65s. Most preferably, the volume ratio of HF to H₂O is 1:(35-50), the cleaning temperature is 25℃, and the cleaning time is 50-60s.

[0043] In ozone-water combined cleaning: A. Ozone partially dissociates in water to generate hydroxyl radicals (•OH). These radicals are very strong oxidants, capable of oxidizing most organic matter and some inorganic matter. B. Ozone and hydroxyl radicals can oxidize certain metals and metal oxides, forming soluble ions or complexes that detach from the wafer surface. C. During wafer processing, ozone and hydroxyl radicals can oxidize some silicon atoms on the surface, forming a thin silicon oxide (SiO2) layer. This oxide layer passivates the surface, preventing recontamination in the air. Due to the high passivation and cleanliness of the surface after DI-O3 cleaning, it improves the compatibility and consistency of the wafer in subsequent process steps, reducing the defect rate.

[0044] ⑩ Spin-drying: Temperature 25-75℃, time 4-12 min, the wafer is in a centrifugal rotation state, the speed is 500-2300 r / min. More preferably: temperature 50-70℃, time 5-10 min. Most preferably: temperature 50-65℃, time 6-9 min.

[0045] The wafer cleaning process provided by this invention is highly targeted at removing contaminants, and the cleaning process is designed based on the mechanism of contaminant removal. Experimental results show that the average number of particles ≥0.2μm on the cleaned wafer can be reduced to less than 100 per wafer.

[0046] The cleaning process for improving wafer surface quality according to the present invention is described in detail below with examples, and should not be construed as a limitation on the scope of protection of the present invention. Example 1

[0047] A silicon carbide substrate after Double CMP was used as the wafer.

[0048] First, an organic solution cleaning is performed by completely immersing the moistened wafer in the solution. The mass ratio of FMES:NMP:MDEA:Na2SiO3:PVP:fatty alcohol polyoxyethylene ether:H2O is 3:12:4:2:0.75:4:74.25, the temperature is 38℃, the time is 15 minutes, and the ultrasonic frequency is 40kHz. The surfactant compound effectively removes wax and other organic matter from the wafer surface, and the ultrasonic waves accelerate the peeling of organic matter from the wafer surface.

[0049] The wafer was further subjected to QDR (Quick Removal) for 7 minutes, followed by ultrasonication at 40 kHz at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface. PVA brushes were used for mechanical cleaning, with unidirectional brushing on both sides of the wafer to prevent scratches. Continuous water spraying was applied during the cleaning process to accelerate the removal of dirt.

[0050] The wafer was further immersed in an organic solution with a mass ratio of PVM / MA:Na3C6H5O7:EDTA-4Na:Na2SiO3:fatty alcohol polyoxyethylene ether:nonylphenol polyoxyethylene ether:H2O = 2:0.8:0.3:1.5:4:2:89.4 at 55°C for 15 minutes, followed by ultrasonication at 40 kHz. This effectively removed the polishing solution residue and made the wafer surface brighter.

[0051] The wafer was further subjected to QDR for 7 minutes, followed by ultrasonication at 40 kHz at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface.

[0052] After pre-cleaning, the wafers were observed under strong light. The surface was clear, free of oil film, cleaning solution residue, polishing fluid residue, large particles such as bright white spots, and water stains. The wafer pass rate was 99.26%. (See attached image) Figure 1 and Figure 2 .

[0053] The wafers are completely immersed in an organic emulsion solution with a mass ratio of SDBS:PVP:OP-10:FMES:H2O = 1.5:0.3:0.5:1:96.7, at 50°C for 10 minutes, and subjected to ultrasonication at 40 kHz. This method can remove organic and inorganic contaminants generated during or partially remaining on the wafers during testing.

[0054] The wafer was further subjected to QDR cleaning for 7 minutes, ultrasonically cleaned at 40 kHz, and at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface.

[0055] The wafers were further treated with SPM (Self-Polluting Processing) at a volume ratio of H2SO4:H2O2 of 9:1, at 95°C for 10 minutes. Then, they were cleaned with HQDR (High-Quality Dry Cleaning) at 75°C for 8 minutes to remove organic residues and large particles (5μm), thus reducing the amount of large particles remaining.

[0056] The treated wafers underwent SC1 cleaning with NH4OH, H2O2, and H2O in a volume ratio of 1:1:5 at 85°C for 10 minutes at a megohmmeter frequency of 950 kHz to remove particles and metal ions. The wafers were then further cleaned using QDR for 5 minutes at room temperature, primarily to remove fine particles and cleaning solution residue.

[0057] The wafer is then subjected to SC2 treatment, with a volume ratio of HCl, H2O2 and H2O of 1:1:10, at a temperature of 65°C for 5 minutes. The wafer is then further subjected to QDR cleaning for 5 minutes, mainly to generate soluble ionic complexes and remove alkali metal ions and metal hydroxides.

[0058] The wafer is further cleaned with DHF (1:10 volume ratio of HF to H2O) at 25°C for 5 minutes. Then, the wafer is further cleaned with QDR (Q-D) for 5 minutes, which mainly removes embedded dirt particles and particles in the shallow oxide layer on the wafer surface through micro-etching, thus further cleaning the wafer surface.

[0059] The wafers were further treated with a low concentration of SC1 (NH4OH, H2O2, and H2O in a volume ratio of 1:1:20) at 85°C for 5 minutes. The wafers were then subjected to QDR (Quick Removal Processing) for 5 minutes to further remove particles.

[0060] The wafers were cleaned using a combination of ozone and water: DI-O3 concentration 30ppm, flow rate 5L / min, time 40s, temperature 25℃; NH4OH:H2O volume ratio 1:5, temperature 45℃, time 60s; HF:H2O volume ratio 1:50, temperature 25℃, time 60s.

[0061] Finally, the wet wafers are dried by hot nitrogen spin drying. The treatment method is to use filtered dry hot nitrogen gas at a temperature of 50°C and a rotation speed of 2000 rpm for 8 minutes.

[0062] The detection was performed according to the implemented method, and the average number of particles >0.2μm on the wafer surface after cleaning was 65.1 per wafer (equipment: Candela 8520). See [link / reference]. Figure 3 , Figure 4 And Table 1. Example 2

[0063] A silicon carbide substrate after Double CMP was used as the wafer.

[0064] First, an organic solution cleaning is performed by completely immersing the moistened wafer in the solution. The mass ratio of the components is FMES:NMP:MDEA:Na2SiO3:PVP:fatty alcohol polyoxyethylene ether:H2O = 1:15:4:2:1:4:73. The temperature is 38℃, the time is 15 minutes, and the ultrasonic frequency is 40kHz. The surfactant compound effectively removes wax and other organic matter from the wafer surface, and the ultrasonic waves accelerate the peeling of organic matter from the wafer surface.

[0065] The wafer was further subjected to QDR (Quick Removal) for 10 minutes, followed by ultrasonication at 40 kHz and room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface. PVA brushes were used for mechanical cleaning, with unidirectional brushing on both sides of the wafer to prevent scratches. Continuous water spraying was applied during the cleaning process to accelerate the removal of dirt.

[0066] The wafer was further immersed in an organic solution with the following composition by mass ratio: PVM / MA:Na3C6H5O7:EDTA-4Na:Na2SiO3:fatty alcohol polyoxyethylene ether:nonylphenol polyoxyethylene ether:H2O = 3:1:0.5:1:4:2:88.5. The solution was heated to 55°C for 15 minutes and then sonicated at 40 kHz to effectively remove polishing solution residue and make the wafer surface more transparent.

[0067] The wafer was further subjected to QDR for 7 minutes, followed by ultrasonication at 40 kHz at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface.

[0068] After pre-cleaning, the wafers were observed under strong light. The surface was clear, free of oil film, cleaning solution residue, polishing fluid residue, large particles such as bright white spots, and water stains. The wafer pass rate was 99.51%. (See [link to relevant documentation]). Figure 5 and Figure 6 .

[0069] The wafers are completely immersed in an organic emulsion solution with a mass ratio of SDBS:PVP:OP-10:FMES:H2O = 1.5:0.3:0.5:1:96.7, at 50°C for 10 minutes, and subjected to ultrasonication at 40 kHz. This method can remove organic and inorganic contaminants generated during or partially remaining on the wafers during testing.

[0070] The wafer was further subjected to QDR cleaning for 7 minutes, ultrasonically cleaned at 40 kHz, and at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface.

[0071] The wafers were further treated with SPM (Surface Purification Processing) at a volume ratio of H2SO4:H2O2 of 9:1, at 95°C for 10 minutes. This was followed by HQDR (High-Quality Dry Cleaning) at 75°C for 8 minutes to remove residual organic matter and particles larger than 5μm, thus reducing the amount of large particles remaining.

[0072] The treated wafers underwent SC1 cleaning with NH4OH, H2O2, and H2O in a volume ratio of 1:1:5 at 85°C for 10 minutes at a megohmmeter frequency of 950 kHz to remove particles and metal ions. The wafers were then further cleaned using QDR for 5 minutes at room temperature, primarily to remove fine particles and cleaning solution residue.

[0073] The wafer is then subjected to SC2 treatment, with a volume ratio of HCl, H2O2 and H2O of 1:1:10, at a temperature of 65°C for 5 minutes. The wafer is then further subjected to QDR cleaning for 5 minutes, mainly to generate soluble ionic complexes and remove alkali metal ions and metal hydroxides.

[0074] The wafer is further cleaned with DHF (1:10 volume ratio of HF to H2O) at 25°C for 5 minutes. Then, the wafer is further cleaned with QDR (Q-D) for 5 minutes, which mainly removes embedded dirt particles and particles in the shallow oxide layer on the wafer surface through micro-etching, thus further cleaning the wafer surface.

[0075] The wafers were further treated with a low concentration of SC1 (NH4OH, H2O2, and H2O in a volume ratio of 1:1:20) at 85°C for 5 minutes. The wafers were then subjected to QDR (Quick Removal Processing) for 5 minutes to further remove particles.

[0076] The wafers were cleaned using a combination of ozone and water: DI-O3 concentration 30ppm, flow rate 5L / min, time 40s, temperature 25℃; NH4OH:H2O volume ratio 1:5, temperature 45℃, time 60s; HF:H2O volume ratio 1:50, temperature 25℃, time 60s.

[0077] Finally, the wet wafers are dried by hot nitrogen spin drying. The treatment method is to use filtered dry hot nitrogen gas at a temperature of 50°C and a rotation speed of 2000 rpm for 8 minutes.

[0078] The detection was performed according to the implemented method, and the average number of particles >0.2μm on the wafer surface after cleaning was 88.4 per wafer (equipment: Candela 8520). Figure 7 , Figure 8 And Table 1. Example 3

[0079] A silicon carbide substrate after Double CMP was used as the wafer.

[0080] First, an organic solution cleaning is performed by completely immersing the moistened wafer in the solution. The mass ratio of FMES:NMP:MDEA:Na2SiO3:PVP:fatty alcohol polyoxyethylene ether:H2O is 3:12:4:2:0.75:4:74.25, the temperature is 38℃, the time is 15 minutes, and the ultrasonic frequency is 40kHz. The surfactant compound effectively removes wax and other organic matter from the wafer surface, and the ultrasonic waves accelerate the peeling of organic matter from the wafer surface.

[0081] The wafer was further subjected to QDR (Quick Removal) for 7 minutes, followed by ultrasonication at 40 kHz at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface. PVA brushes were used for mechanical cleaning, with unidirectional brushing on both sides of the wafer to prevent scratches. Continuous water spraying was applied during the cleaning process to accelerate the removal of dirt.

[0082] The wafer was further immersed in an organic solution with a mass ratio of PVM / MA:Na3C6H5O7:EDTA-4Na:Na2SiO3:fatty alcohol polyoxyethylene ether:nonylphenol polyoxyethylene ether:H2O = 2:0.8:0.3:1.5:4:2:89.4 at 55°C for 15 minutes, followed by ultrasonication at 40 kHz. This effectively removed the polishing solution residue and made the wafer surface brighter.

[0083] The wafer was further subjected to QDR for 7 minutes, followed by ultrasonication at 40 kHz at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface.

[0084] After pre-cleaning, the wafers were observed under strong light. The surface was clear, free of oil film, cleaning solution residue, polishing fluid residue, large particles such as bright white spots, and water stains. The wafer pass rate was 98.73%. (See [link to relevant documentation]). Figure 9 , Figure 10 And Table 1.

[0085] The wafer is completely immersed in an organic emulsion solution with a mass ratio of SDBS:PVP:OP-10:FMES:H2O of 1:0.5:0.5:2:96, at 45°C for 10 minutes, and ultrasonicated at 40 kHz. This process can remove organic and inorganic contaminants generated during testing or partially remaining on the wafer.

[0086] The wafer was further subjected to QDR cleaning for 8 minutes, ultrasonicated at 40 kHz, and at room temperature to remove stubborn impurities and residual cleaning solution from the wafer surface.

[0087] The wafers were further treated with SPM (Surface Purification Processing) at a volume ratio of H2SO4:H2O2 of 8:2, at 100°C for 10 minutes. Then, they were cleaned with HQDR (High-Quality Dry Cleaning) at 75°C for 8 minutes to remove organic residues and particles larger than 5μm, thus reducing the amount of large particles remaining.

[0088] The treated wafers underwent SC1 cleaning with NH4OH, H2O2, and H2O in a volume ratio of 1:1:5 at 85°C for 10 minutes at a megohmmeter frequency of 950 kHz to remove particles and metal ions. The wafers were then further cleaned using QDR for 5 minutes at room temperature, primarily to remove fine particles and cleaning solution residue.

[0089] The wafer is then treated with SC2 (HCl, H2O2, and H2O in a volume ratio of 1:1:10, at 65°C for 5 minutes); the wafer is then further cleaned with QDR (Quick Removal) for 5 minutes, mainly to generate soluble ionic complexes and remove alkali metal ions and metal hydroxides.

[0090] The wafer is further cleaned with DHF (1:10 volume ratio of HF to H2O) at 25°C for 5 minutes. Then, the wafer is further cleaned with QDR (Q-D) for 5 minutes, which mainly removes embedded dirt particles and particles in the shallow oxide layer on the wafer surface through micro-etching, thus further cleaning the wafer surface.

[0091] The wafers were further treated with a low concentration of SC1 (NH4OH, H2O2, and H2O in a volume ratio of 1:1:20) at 85°C for 5 minutes. The wafers were then subjected to QDR (Quick Removal Processing) for 5 minutes to further remove particles.

[0092] The wafers were cleaned using a combination of ozone and water: DI-O3 concentration 30ppm, flow rate 5L / min, time 40s, temperature 25℃; NH4OH:H2O volume ratio 1:5, temperature 45℃, time 60s; HF:H2O volume ratio 1:50, temperature 23℃, time 60s.

[0093] Finally, the wet wafers are dried by hot nitrogen spin drying. The treatment method is to use filtered dry hot nitrogen gas at a temperature of 50°C and a rotation speed of 2000 rpm for 8 minutes.

[0094] The detection was performed according to the implemented method. After cleaning, the average number of particles >0.2μm on the wafer surface was 86.2 per wafer (equipment: Candela 8520). See figure. Figure 11 , Figure 12 And Table 1.

[0095] Table 1. Particle detection data for each embodiment ; ; The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cleaning process for improving wafer surface quality, characterized in that, Includes the following steps: (1) Wafer pre-cleaning ① First organic solution cleaning: The mechanically polished wafer is ultrasonically cleaned with a first organic solution; the first organic solution includes surfactants, alkanolamines, chelating agents, penetrants and water; ② Pure water ultrasonic cleaning: ultrasonic frequency is 55-80KHz, cleaning time is 5-20min; ③ Mechanical brushing: Use a brush to wipe the non-use surface and the use surface of the wafer separately; ④ Second organic solution cleaning: The second organic solution includes surfactants, chelating agents, penetrants, and water; ultrasonic cleaning; (2) Chip terminal cleaning ① Cleaning with organic emulsion solutions: Organic emulsion solutions include surfactants and water; ultrasonic cleaning; ②SPM cleaning: The volume ratio of H2SO4 to H2O2 in the cleaning solution is (5.1-9.9):1; ③HQDR cleaning: Cleaning temperature is 45-75℃, and cleaning time is 4-20 minutes; ④ High-concentration SC1 cleaning: The volume ratio of NH4OH, H2O2, and H2O in the cleaning solution is 1:(0.5-2.3):(4.2-7.5); megasonic cleaning; ⑤QDR cleaning: Cleaning temperature is room temperature, cleaning time is 4-20 minutes, and ultrasonic frequency is 25-55KHz; ⑥SC2 cleaning: The volume ratio of HCl, H2O2 and H2O in the cleaning solution is 1:(0.5-2.5):(7.5-12.5); ⑦ DHF cleaning: The volume ratio of HF to H2O in the cleaning solution is 1:(7.5-20.5). ⑧ Low-concentration SC1 cleaning: The volume ratio of NH4OH, H2O2, and H2O in the cleaning solution is 1:(0.5-2.5):(8-23); megasonic cleaning; ⑨ Ozone water combination cleaning: including DI-O3 cleaning, NH4OH-H2O cleaning and DHF cleaning; ⑩ Spin-drying: The temperature is 25-75℃, the time is 4-12min, the wafer is in a centrifugal rotation state, and the speed is 500-2300r / min.

2. The cleaning process for improving wafer surface quality according to claim 1, characterized in that, In step (1) ① the reagents of the first organic solution, the surfactant is selected from one or more of fatty acid methyl ester ethoxylate, fatty acid methyl ester ethoxylate sulfonate, fatty alcohol polyoxyethylene ether, dodecylphenol polyoxyethylene ether, polyvinylpyrrolidone, propylene glycol methyl ether acetate, and N-methylpyrrolidone; the alkanolamine is selected from one or more of N-methyldiethanolamine and triethanolamine; the chelating agent is selected from one or more of sodium citrate, tetrasodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, nano-sized sodium silicate, and nano-sized potassium silicate; the penetrant is selected from one or more of p-methoxy fatty amide benzenesulfonic acid, nonylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; the cleaning temperature is 25-55℃, the cleaning time is 5-25min, and the ultrasonic frequency is 25-55KHz.

3. The cleaning process for improving wafer surface quality according to claim 2, characterized in that, In step (1) ① the mass percentages of fatty acid methyl ester ethoxylate sulfonate, N-methylpyrrolidone, N-methyldiethanolamine, sodium silicate, polyvinylpyrrolidone, and fatty alcohol polyoxyethylene ether in the first organic solution are 2%-5%, 10%-15%, 3%-5%, 1%-3%, 0.5%-1%, and 2%-5%, respectively, which are made up to 100% by water. The reagents are industrial grade and the water is ultrapure water. The cleaning temperature is 30-40℃, the cleaning time is 10-20min, and the ultrasonic frequency is 30-45KHz.

4. The cleaning process for improving wafer surface quality according to claim 1, characterized in that, In step (1) ④, the reagents in the second organic solution include: surfactants selected from one or more of methyl vinyl ether-maleic anhydride copolymer, fatty alcohol amine ethoxylate, and maleic anhydride alcohol amine copolymer; chelating agents selected from one or more of sodium citrate, tetrasodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, nano-sized sodium silicate, and nano-sized potassium silicate; penetrants selected from one or more of p-methoxy fatty amide benzenesulfonic acid, nonylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; cleaning temperature of 25-55℃, cleaning time of 5-25min, and ultrasonic frequency of 25-55KHz.

5. The cleaning process for improving wafer surface quality according to claim 4, characterized in that, In step (1) ④, the mass percentages of the second organic solution, namely methyl vinyl ether-maleic anhydride copolymer, sodium citrate, tetrasodium ethylenediaminetetraacetate, sodium silicate, fatty alcohol polyoxyethylene ether, and nonylphenol polyoxyethylene ether, are 1%-3%, 0.5%-1%, 0.1%-0.5%, 0.5%-2%, 2%-5%, and 1%-3%, respectively, are made up to 100% by water. The reagents are industrial grade, and the water is ultrapure water. The cleaning temperature is 40-55℃, the cleaning time is 10-20 min, and the ultrasonic frequency is 30-45 kHz.

6. The cleaning process for improving wafer surface quality according to claim 1, characterized in that, The step (2) ① organic emulsifying cleaning surfactant includes one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, polyoxyethylene (10) nonylphenol ether, polyoxyethylene-15-nonylphenol ether, fatty acid methyl ester ethoxylate, polyvinylpyrrolidone, and sodium octylbenzene sulfonate; the cleaning temperature is 25-55℃, the cleaning time is 5-25min, and the ultrasonic frequency is 25-55KHz.

7. The cleaning process for improving wafer surface quality according to claim 6, characterized in that, In step (2) ① the organic emulsion cleaning solution, the mass percentages of sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, polyoxyethylene (10) nonylphenol ether, and fatty acid methyl ester ethoxylate are 0.5%-2%, 0.1%-0.5%, 0.1%-1%, and 0.5%-2%, respectively, which are made up to 100% by water. The reagents are industrial grade and the water is ultrapure water. The cleaning temperature is 45-55℃, the cleaning time is 5-15min, and the ultrasonic frequency is 30-45KHz.

8. The cleaning process for improving wafer surface quality according to claim 1, characterized in that, Step (2) ② SPM cleaning: the mass concentration of H2SO4 reagent is 96%-98%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 80-120℃, and the cleaning time is 4-20min; Step (2) ⑥ SC2 cleaning: the mass concentration of HCl reagent is 36%-38%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 60-85℃, and the cleaning time is 4-20min; Step (2) ⑦ DHF cleaning: the mass concentration of HF reagent is 48%-49%, the cleaning temperature is 20-30℃, and the cleaning time is 3-12min.

9. The cleaning process for improving wafer surface quality according to claim 1, characterized in that, In step (2) ④ high concentration SC1 cleaning and step (2) ⑧ low concentration SC1 cleaning: the mass concentration of H4OH reagent is 28%-30%, the mass concentration of H2O2 reagent is 30%-32%, the cleaning temperature is 65-90℃, the cleaning time is 4-20min; the megaphonic cleaning frequency is 800-1000KHz.

10. The cleaning process for improving wafer surface quality according to claim 1, characterized in that, In step (2) ⑨ ozone water combined cleaning, the DI-O3 concentration is 15-45ppm, the humidity is ≤90%RH, the flow rate is 2.5-6.5L / min, the cleaning temperature is 15-40℃, and the cleaning time is 15-65s; the volume ratio of NH4OH-H2O is 1:(3.5-8.5), the mass concentration of NH4OH reagent is 28%-30%, the cleaning temperature is 25-60℃, and the cleaning time is 25-90s; in the DHF cleaning reagent, the volume ratio of HF and H2O is 1:(25-75), the mass concentration of HF reagent is 48%-49%, the cleaning temperature is 20-30℃, and the cleaning time is 25-90s.

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