Plasma cutting protection liquid, and preparation method therefor and use thereof

Abstract

A plasma cutting protection liquid, and a preparation method therefor, and a use thereof. The plasma cutting protection liquid comprises, in parts by mass: 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanoscale inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber, and 50 to 100 parts of a solvent, wherein the water-soluble resin contains amide groups, and the water-soluble resin is a partially cross-linked resin. By using the partially cross-linked resin containing the amide groups, the partially cross-linked structure can form a three-dimensional network structure to inhibit molecular movement so as to improve the high-temperature resistance. The resin contains a large number of hydrophilic amide groups, which extremely easily form hydrogen bonds with water. After a cutting process is completed, a film layer formed by the protection liquid can be easily removed, and the cleaning process is simple. The inorganic particles can further improve the heat-resistant temperature of the cutting protection liquid and can also improve the compactness of the film layer, thereby facilitating the formation of a uniform film layer.

Description

A plasma cutting protective fluid and its preparation method and application

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on March 29, 2024, with application number 202410374224.2 and application name “A plasma cutting protective fluid, its preparation method and application”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the field of semiconductor cutting technology, and specifically relates to a plasma cutting protective liquid and a preparation method and application thereof. Background Art

[0003] After integrated circuits are formed on a wafer (also known as a substrate) made of semiconductor material, the wafer is cut into pieces to obtain semiconductor device components. The cutting method is sawing, which can cut a large number of wafers in a short period of time. However, if the feed speed of the slices is greatly increased, the possibility of the edges of the small chips peeling off will increase, which will greatly reduce the product yield. Based on this, a method has emerged that uses methods such as ionized gas discharge to generate high-temperature plasma on the material and use its high energy to cut the material. However, plasma cutting has high cutting requirements. Before plasma cutting, it is necessary to apply a cutting protection liquid on the wafer surface. After the protective film is formed, a laser is used to cut grooves in the protective film, and then the plasma is used to completely cut the wafer. Therefore, the plasma cutting protection liquid also needs to have a certain absorption capacity for the laser. In particular, for the film layer formed by the cutting protection liquid, the plasma cutting protection liquid must take into account high temperature resistance, film thickness, and film uniformity. Otherwise, the yield and productivity of the semiconductor wafer manufacturing process cannot be guaranteed. Technical issues

[0004] The present application provides a plasma cutting protective liquid and its preparation method and application, which can be applied to both laser cutting and plasma cutting, thereby improving the yield and productivity in the semiconductor manufacturing process. Technical Solutions

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] In a first aspect, a plasma cutting protection fluid is provided, comprising the following components, in parts by mass: 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanoscale inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber, and 50 to 100 parts of a solvent;

[0007] Wherein, the water-soluble resin contains an amide group, and the water-soluble resin is a partially cross-linked resin.

[0008] Optionally, the water-soluble resin is prepared by polymerization of a reactive monomer and a cross-linking agent; wherein the reactive monomer is a compound containing a double bond and the amide group, and the cross-linking agent is a compound containing a bifunctional group.

[0009] Optionally, the mass ratio of the reactive monomer to the cross-linking agent is 60-120:0.2-0.5.

[0010] Optionally, the reactive monomer is selected from at least one of acrylamide, methacrylamide, N-isopropylacrylamide, N-vinylacetamide, N-hydroxymethylacrylamide, and N,N-dimethylacrylamide; and / or the cross-linking agent is selected from at least one of ethylene glycol diacrylate, N,N'-methylenebisacrylamide, and bis(methyl methacrylate)diisopropoxysilane.

[0011] Optionally, the molecular weight of the water-soluble resin is 1000 to 3000.

[0012] Optionally, the nanoscale inorganic particles are selected from at least one of Al2O3, Fe2O3, ZnO, TiO2, ZrO, SiO2, and montmorillonite; wherein the average particle size of the nanoscale inorganic particles is 1 to 50 nm.

[0013] Optionally, the cosolvent is selected from at least one of nicotinamide, acetamide, and carbonamide; and / or

[0014] The flow promoter is selected from reactive acrylate leveling agents; and / or

[0015] The solvent is selected from at least one of water, alcohol and ether.

[0016] Optionally, the ultraviolet light absorber is selected from at least one of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, N-(2-ethoxyphenyl)-N'-(4-ethylphenyl)-ethanediamide, 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid sodium, 2-cyano-3,3-diphenylacrylate-2-ethylhexyl ester, and o-nitroaniline.

[0017] In a second aspect, the present application also provides a method for preparing a plasma cutting protection liquid, comprising the following steps:

[0018] Under a protective atmosphere, the reaction monomer, the cross-linking agent and the initiator are mixed, heated, stirred and reacted to prepare a water-soluble resin;

[0019] 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanometer-sized inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber and 50 to 100 parts of a solvent are weighed, mixed, heated and stirred to obtain a plasma cutting protection liquid.

[0020] In a third aspect, the present application also provides an application of a plasma cutting protection liquid in wafer cutting, wherein the size of the wafer is 4 to 12 inches. Beneficial effects

[0021] Compared with the prior art, the plasma cutting protection fluid of the present application includes the following components, in parts by mass: 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanoscale inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber and 50 to 100 parts of a solvent; wherein the water-soluble resin contains an amide group, and the water-soluble resin is a partially cross-linked resin. The cutting protection liquid of the present application uses a resin containing amide groups and partially cross-linked. The partially cross-linked structure can form a three-dimensional network structure to inhibit molecular movement to achieve the purpose of improving high-temperature resistance. The resin contains a large number of hydrophilic amide groups, which can easily form hydrogen bonds with water. After the cutting process is completed, the film layer formed by the protection liquid can be easily removed, and the cleaning process is simple; at the same time, nano-scale inorganic particles can further improve the heat resistance temperature of the cutting protection liquid, and can also increase the density of the film layer, which is conducive to the formation of a uniform film layer; the present application provides a protection liquid that is suitable for both laser cutting and plasma cutting, which can improve the yield and productivity in the semiconductor manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is an infrared spectrum of the water-soluble resin prepared in Example 1;

[0023] FIG2 is a picture of the wafer surface after the cutting protection liquid prepared in Example 1 is coated;

[0024] FIG3 is a picture of the wafer surface after the cutting protection liquid prepared in Comparative Example 1 is coated.

[0025] Implementation Methods of the Application

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. The described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0027] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0028] Semiconductors are materials with electrical conductivity between conductors and insulators at room temperature. Semiconductors are used in integrated circuits, consumer electronics, communications systems, photovoltaic power generation, lighting, and high-power power conversion. Diodes, for example, are devices made from semiconductors. The core components of most electronic products, such as computers, mobile phones, and digital recorders, are closely tied to semiconductors.

[0029] Common semiconductor materials include silicon, germanium, gallium arsenide, etc. Silicon is the most influential type of semiconductor material in various applications. After the integrated circuit is formed on the wafer (also known as the substrate) composed of semiconductor materials, the wafer is cut. Slicing methods include sawing. Sawing has always been the most widely used cutting method. Its biggest advantage is that a large number of wafers can be cut in a short time. However, if the feed speed of the slices is greatly increased, the possibility of peeling off the edges of the small chips will become greater, which will greatly reduce the product yield. As the chip size becomes smaller and the precision becomes higher, sawing can no longer meet the cutting needs.

[0030] Plasma cutting emerged as a necessary step in this process, and can be broadly categorized into coating, cutting, and cleaning. Plasma cutting utilizes methods such as ionized gas discharge to generate high-temperature plasma on the material, leveraging its high energy to cut the material. This process generates a significant amount of heat, so the final film of plasma cutting protective fluid must possess excellent high-temperature resistance. During plasma cutting, the plasma not only etches the exposed cutting lanes, but also the film coated with the cutting protective fluid. If the film is not thick enough, the protective film will be etched away before the plasma has completed the cutting lanes. After the film is etched away, the plasma will continue to etch the chip, causing irreparable damage. Therefore, a sufficiently thick film of plasma cutting protective fluid is essential. Furthermore, film uniformity is also crucial. To ensure this, the protective fluid viscosity must be kept to a minimum. Lower viscosity results in greater fluidity and improved leveling, making it easier to form a uniform film. The wafer sizes are 4 inches, 6 inches, 8 inches, 12 inches, etc. As the wafer size increases, uniform coating becomes more difficult, especially for 12-inch wafers, which are the most difficult wafers to coat. For 12-inch wafers, simply reducing the viscosity cannot guarantee the coating effect.

[0031] Based on this, it is necessary to provide a plasma cutting protection liquid to solve the above problems.

[0032] An embodiment of the present application provides a plasma cutting protection fluid, which includes the following components, in parts by mass: 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanoscale inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber, and 50 to 100 parts of a solvent; wherein the water-soluble resin contains an amide group and is a partially cross-linked resin.

[0033] In some embodiments, the plasma cutting protection fluid further comprises, by weight, 10 to 35 parts of a water-soluble resin, 2 to 8 parts of a cosolvent, 0.3 to 6 parts of nanoscale inorganic particles, 0.5 to 2 parts of a flow promoter, 0.15 to 0.45 parts of an ultraviolet light absorber, and 60 to 90 parts of a solvent.

[0034] In some embodiments, the plasma cutting protection fluid further comprises, by weight, 15 to 30 parts of a water-soluble resin, 3 to 6 parts of a cosolvent, 0.5 to 5 parts of nanoscale inorganic particles, 0.5 to 1.5 parts of a flow promoter, 0.2 to 0.4 parts of an ultraviolet light absorber, and 70 to 85 parts of a solvent.

[0035] It can be understood that the cutting protection liquid uses a partially cross-linked resin containing amide groups. The partially cross-linked structure can form a three-dimensional network structure to inhibit molecular movement to achieve the purpose of improving high-temperature resistance. The resin contains a large number of hydrophilic amide groups, which can easily form hydrogen bonds with water. After the cutting process is completed, the film layer formed by the protection liquid can be easily removed, and the cleaning process is simple.

[0036] Furthermore, although the water solubility and water washability of the resin will deteriorate after cross-linking, the resin in this embodiment is partially cross-linked, so the uncross-linked water-soluble resin coexists with the cross-linked resin. After film formation, the uncross-linked part is the washable part, which can lead to the difficult-to-clean part after cross-linking to be washed away together.

[0037] In some embodiments, the water-soluble resin is prepared by polymerization of a reactive monomer and a cross-linking agent; wherein the reactive monomer is a compound containing a double bond and an amide group, and the cross-linking agent is a compound containing a bifunctional group.

[0038] It is understandable that the double bonds in the reactive monomers can react with the cross-linking agent to form cross-linking points, thereby further obtaining a three-dimensional network structure to improve the high temperature resistance of the cutting protection liquid. In addition, the film-forming properties of the cross-linked resin will be better. This is because the three-dimensional network structure also enhances the interaction force between the resin molecules. When forming a film, its molecules can be more tightly connected to the wafer surface, so that the strength and stability of the film are improved. Among them, the degree of cross-linking can be determined by differential thermal analysis, nuclear magnetic resonance, etc. The resin contains a large number of hydrophilic amide groups, which can easily form hydrogen bonds with water. After the cutting process is completed, the film layer formed by the protective liquid can be easily removed, and the cleaning process is simple. The bifunctional groups in the cross-linking agent can form more cross-linking points and increase the density of partial cross-linking, which can make the resin form a tighter network structure, increase the interaction force between the resin molecules, and improve thermal stability and high temperature resistance.

[0039] In some embodiments, the reactive monomer is selected from at least one of acrylamide, methacrylamide, N-isopropylacrylamide, N-vinylacetamide, N-hydroxymethylacrylamide, and N,N-dimethylacrylamide. It is understood that the CAS number of acrylamide is 79-06-1, the CAS number of methacrylamide is 79-39-0, the CAS number of N-isopropylacrylamide is 2210-25-5, the CAS number of N-vinylacetamide is 5202-78-8, the CAS number of N-hydroxymethylacrylamide is 924-42-5, and the CAS number of N,N-dimethylacrylamide is 2680-03-7. Each of the above reactive monomers can be purchased through commercial channels and will not be described in detail here.

[0040] The crosslinking agent is selected from at least one of ethylene glycol diacrylate, N,N'-methylenebisacrylamide, and ethylene glycol dimethacrylate. It is understood that the CAS number for ethylene glycol diacrylate is 2274-11-5, the CAS number for N,N'-methylenebisacrylamide is 110-26-9, and the CAS number for ethylene glycol dimethacrylate is 97-90-5. Each of the above crosslinking agents is commercially available and will not be described in detail here.

[0041] In some embodiments, the molecular weight of the water-soluble resin is 1000 to 3000. For example, the molecular weight of the water-soluble resin can be any one of 1000, 1500, 2000, 2500, 3000 or a range between any two values. The smaller the molecular weight of the water-soluble resin, the lower the viscosity, which is more conducive to increasing the solid content, and the formed film layer has the characteristics of high film thickness; the molecular weight of the water-soluble resin is too small, resulting in poor high temperature resistance, and the molecular weight is too large, resulting in high overall viscosity and poor film uniformity. Therefore, by controlling the polymerization conditions to make the molecular weight of the water-soluble resin range from 1000 to 3000, the resin has excellent film-forming properties within this molecular weight range, forms a complete protective film on the surface of the substrate, and can prepare a high-thickness protective liquid under low viscosity. Moreover, the heat resistance of the resin is improved while ensuring water solubility.

[0042] In some embodiments, the degree of crosslinking refers to the degree of crosslinking (chemical bonding) within a polymer or resin. In a resin with a high degree of crosslinking, the crosslinking structure between the polymer chains is relatively tight, so that the resin forms a three-dimensional network structure.

[0043] In some embodiments, the nano-scale inorganic particles are selected from at least one of Al2O3, Fe2O3, ZnO, TiO2, ZrO, SiO2, and montmorillonite; wherein the average particle size of the nano-scale inorganic particles is in the range of 1 to 50 nm. It is understandable that the nano-scale inorganic particles can also further improve the heat resistance temperature of the cutting protection liquid, increase the density of the film layer, make its etching resistance stronger, increase the etching selectivity, and ensure that the substrate is not damaged during the etching process. The smaller the average particle size of the nano-scale inorganic particles, the better the modification effect, the more uniform and stable the dispersion in the solution, and the more conducive to the formation of a uniform film layer. The nano-scale inorganic particles are made of inorganic substances with a temperature resistance of more than 1000°C. The smaller the particle size, the more uniform and stable the dispersion, and the more it can fill the gaps in the film layer, thereby improving the density of the film layer.

[0044] In some embodiments, the average particle size of the nanoscale inorganic particles is 1 to 50 nm. For example, the average particle size can be any one of 1 nm, 2 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, and 50 mm, or a range between any two of these values. Further optionally, the average particle size of the nanoscale inorganic particles is 1 to 20 nm.

[0045] In some embodiments, the nano-sized inorganic particles may further be at least one of SiO2 and montmorillonite, wherein the CAS number of montmorillonite is 1318-93-0.

[0046] In some embodiments, the cosolvent is selected from at least one of nicotinamide, acetamide, and carbonamide. It is understood that the cosolvent can form soluble intermolecular complexes, associate compounds, etc. with the partially cross-linked insoluble resin in the solvent, thereby increasing the solubility of the partially cross-linked resin in the solvent. Cosolvents are water-soluble and are mostly low-molecular compounds. Cosolvents are selected based on the properties of the substance and are capable of forming water-soluble intermolecular complexes, double salts, or associate compounds with it. Preferred cosolvents are nicotinamide, acetamide, etc., as they all have amide groups and similar structures to the resin. Due to the property of like dissolving like, the cosolvent and the polymerized resin are extremely compatible. This system provides a highly stable protective solution and is more likely to form a uniform and stable film layer.

[0047] In some embodiments, the flow promoter is selected from a reactive acrylate leveling agent. For example, the flow promoter can be selected from at least one of Moen Chemical's grades 1073 and 1074, which have good compatibility and excellent slip. Alternatively, one can select any of Zhuhai Xiande's synde-124, synde-125, and synde-126 products. Synde-124 and synde-125 are acrylate copolymers, while synde-126 is a fluorocarbon-modified polyacrylate leveling agent. All three have the advantages of improving leveling and flowability, maintaining recoatability and interlayer adhesion, and preventing defects such as craters, pinholes, and fisheyes in the coating.

[0048] In some embodiments, the solvent is selected from at least one of water, alcohol, and ether. Water is deionized water; alcohols can be, for example, any one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, and isobutanol; and ethers can be, for example, any one or more of ethyl ether, methyl ethyl ether, di-n-butyl ether, propylene glycol methyl ether, and ethylene glycol propyl ether. Deionized water, isopropanol, propylene glycol methyl ether, or any combination thereof are preferred; a combination of deionized water and propylene glycol methyl ether is most preferred.

[0049] In some embodiments, the UV absorber is selected from at least one of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, N-(2-ethoxyphenyl)-N'-(4-ethylphenyl)-oxalamide, sodium 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, and o-nitroaniline. It is understood that both plasma cutting and laser cutting involve a laser cutting and grooving step, thus requiring the addition of a UV absorber. The UV absorber is selected from a benzene ring absorber with a conjugated structure that ensures a strong absorption peak at 355 nm, enabling rapid and complete absorption of laser energy, ensuring timely film blasting without damaging the wafer beneath the film.

[0050] In some embodiments, a method for preparing a plasma cutting protection liquid is also provided, comprising the following steps:

[0051] Under a protective atmosphere, the reaction monomer, the cross-linking agent and the initiator are mixed, heated, stirred and reacted to prepare a water-soluble resin;

[0052] 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanometer-sized inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber and 50 to 100 parts of a solvent are weighed, mixed, heated and stirred to obtain a plasma cutting protection liquid.

[0053] In some embodiments, the mass ratio of the reactive monomer to the cross-linking agent is 60-120:0.2-0.5, for example, a further optional mass ratio is 100:0.3.

[0054] In some embodiments, the amount of initiator used is 0.2-1.5 parts, optionally 0.5-1 parts, and further optionally 0.8 parts.

[0055] In some embodiments, the initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, and ammonium persulfate.

[0056] In some embodiments, the stirring speed is in the range of 200 to 500 rpm, for example, 200 rpm, 300 rpm, 400 rpm, or 500 rpm, and the stirring time is in the range of 1 to 5 h, for example, 1 h, 2 h, 3 h, 4 h, or 5 h.

[0057] In some embodiments, the plasma cutting protection liquid provided in this embodiment can be used in wafer cutting, wherein the size of the wafer is 4 to 12 inches.

[0058] Taking 12-inch wafers as an example, the specific application methods are as follows:

[0059] First clean the 12-inch wafer to be coated;

[0060] Set up the spin coating program, add the cutting protection liquid of this embodiment to the wafer in an amount ranging from 35 to 40 mL, and spin coat at 1000 rpm for 2 minutes;

[0061] After spin coating, the next cutting process can be carried out.

[0062] In some embodiments, the aforementioned cutting protection fluid can adapt to various wafer structures, forming a protective film on the wafer surface to prevent the wafer from being scratched by debris during the cutting process, thereby improving the yield rate of semiconductor products and cutting efficiency. The protective fluid of the present application has very good application prospects and potential for large-scale industrial promotion in the field of semiconductor cutting protection.

[0063] The cutting protection liquids of Examples 1-12 are provided respectively, and the specific components are shown in Table 1.

[0064] Table 1

[0065] Example 1

[0066] In Table 1, the water-soluble resin of Example 1 is prepared by reacting N,N-dimethylacrylamide and ethylene glycol diacrylate, and the preparation method is as follows: under nitrogen protection, N,N-dimethylacrylamide and ethylene glycol diacrylate in a mass ratio of 100:0.3 are mixed with 0.8 parts of azobisisobutyronitrile, and added to a reactor containing propylene glycol methyl ether; the reactor is heated to 80°C; the reactants are heated and stirred for 8 hours to obtain a water-soluble resin. Wherein, the molecular weight of the water-soluble resin is 2000, and the water-soluble resin is partially cross-linked, and the degree of partial cross-linking is determined by the mass ratio.

[0067] See Figure 1, which is the infrared spectrum of the water-soluble resin prepared by the reaction of N,N-dimethylacrylamide and ethylene glycol diacrylate. From Figure 1, we can see that the infrared spectrum at 1650 cm -1 and 1350cm -1 is the characteristic peak of amide group; 1723cm -1 Carbonyl C=O stretching vibration; 3004cm -1 、2965cm -1 、2926cm -1 is the stretching vibration of -CH3, 1421cm -1 and 1362cm -1 The bending vibration of -CH3 indicates that the partially cross-linked water-soluble resin was successfully synthesized.

[0068] Example 2

[0069] In Table 1, the water-soluble resin of Example 2 is prepared by reacting N,N-dimethylacrylamide and N,N'-methylenebisacrylamide, and the preparation method is as follows: under nitrogen protection, N,N-dimethylacrylamide and N,N'-methylenebisacrylamide with a mass ratio of 60:0.5 and 0.2 parts of azobisisobutyronitrile are mixed and added to a reactor containing propylene glycol methyl ether; the reactor is heated to 80 ° C; the reactants are heated and stirred for 8 hours to obtain a water-soluble resin. Wherein, the molecular weight of the water-soluble resin is 3000, and the water-soluble resin is partially cross-linked, and the degree of partial cross-linking is determined by the mass ratio.

[0070] Example 3

[0071] In Table 1, the water-soluble resin of Example 3 is prepared by reacting N, N-dimethylacrylamide and ethylene glycol diacrylate, and the preparation method is as follows: under nitrogen protection, N, N-dimethylacrylamide and ethylene glycol diacrylate in a mass ratio of 120:0.2 are mixed with 1.5 parts of azobisisobutyronitrile, and added to a reactor containing propylene glycol methyl ether; the reactor is heated to 80 ° C; the reactants are heated and stirred for 8 hours to obtain a water-soluble resin. Wherein, the molecular weight of the water-soluble resin is 2500, and the water-soluble resin is partially cross-linked, and the degree of partial cross-linking is determined by the mass ratio.

[0072] Example 4

[0073] In Table 1, the water-soluble resin of Example 4 is prepared by reacting N,N-dimethylacrylamide and ethylene glycol diacrylate, and the preparation method is as follows: under nitrogen protection, N,N-dimethylacrylamide and ethylene glycol diacrylate in a mass ratio of 100:0.4 are mixed with 0.5 parts of azobisisobutyronitrile, and added to a reactor containing propylene glycol methyl ether; the reactor is heated to 80 ° C; the reactants are heated and stirred for 8 hours to obtain a water-soluble resin. Wherein, the molecular weight of the water-soluble resin is 1500, and the water-soluble resin is partially cross-linked, and the degree of partial cross-linking is determined by the mass ratio.

[0074] Example 5

[0075] In Table 1, the water-soluble resin of Example 5 is prepared by reacting N,N-dimethylacrylamide and N,N'-methylenebisacrylamide. The preparation method is as follows: under nitrogen protection, N,N-dimethylacrylamide and N,N'-methylenebisacrylamide in a mass ratio of 80:0.3 are mixed with 1 part of azobisisobutyronitrile and added to a reactor containing propylene glycol methyl ether; the reactor is heated to 80°C; the reactants are heated and stirred for 8 hours to obtain a water-soluble resin. The molecular weight of the water-soluble resin is 2000, and the water-soluble resin is partially cross-linked, and the degree of partial cross-linking is determined by the mass ratio.

[0076] Example 6

[0077] In Table 1, the water-soluble resin of Example 6 is prepared by reacting N, N-dimethylacrylamide and bis(methyl methacrylate) diisopropoxysilane, and the preparation method is as follows: under nitrogen protection, N, N-dimethylacrylamide and bis(methyl methacrylate) diisopropoxysilane with a mass ratio of 120:0.5 are mixed with 1.2 parts of azobisisobutyronitrile, and added to a reactor equipped with propylene glycol methyl ether; the reactor is warmed to 80 ° C; the reactants are heated and stirred, and after 8 hours, a water-soluble resin is obtained. Wherein, the molecular weight of the water-soluble resin is 1000, and the water-soluble resin is partially cross-linked, and the degree of partial cross-linking is determined by the mass ratio.

[0078] Examples 7-12

[0079] The water-soluble resin of Example 7 is prepared by reacting acrylamide and ethylene glycol diacrylate, and the preparation method is the same as that of Example 1.

[0080] The water-soluble resin of Example 8 is prepared by reacting N-isopropylacrylamide and ethylene glycol diacrylate, and the preparation method is the same as that of Example 1.

[0081] The water-soluble resin of Example 9 is prepared by reacting N-vinylacetamide and ethylene glycol diacrylate, and the preparation method is the same as that of Example 1.

[0082] The water-soluble resin of Example 10 is prepared by reacting N-hydroxymethyl acrylamide and ethylene glycol diacrylate, and the preparation method is the same as that of Example 1.

[0083] The water-soluble resin of Example 11 is prepared by reacting methacrylamide and ethylene glycol diacrylate, and the preparation method is the same as that of Example 1.

[0084] The water-soluble resin of Example 12 is prepared by reacting N-vinylacetamide and ethylene glycol diacrylate, and the preparation method is the same as that of Example 1.

[0085] The cutting protection liquids of Comparative Examples 1-8 are provided. For specific components, see Table 2.

[0086] Table 2

[0087] The only difference between Comparative Example 1 and Example 1 is the degree of crosslinking of the water-soluble resin. Specifically, the water-soluble resin of Comparative Example 1 was prepared by mixing N,N-dimethylacrylamide, ethylene glycol diacrylate, and 0.8 parts of azobisisobutyronitrile in a mass ratio of 50:1 under nitrogen and adding the mixture to a reactor containing propylene glycol methyl ether; heating the reactor to 80°C; and heating and stirring the reactants for 8 hours to obtain a water-insoluble resin. The water-insoluble resin had a molecular weight of 5000 and was partially soluble in water.

[0088] The only difference between Comparative Example 2 and Example 1 is that the crosslinking degree of the water-soluble resin is different. Specifically, the preparation method of the water-soluble resin in Comparative Example 2 is: no crosslinking agent is added, and in this case, a water-soluble resin with a certain degree of crosslinking cannot be obtained.

[0089] The only difference between Comparative Example 3 and Example 1 is that the degree of crosslinking of the water-soluble resin is different. Specifically, the water-soluble resin of Comparative Example 3 is prepared by mixing N,N-dimethylacrylamide, ethylene glycol diacrylate, and 0.8 parts of azobisisobutyronitrile in a mass ratio of 150:0.1 under nitrogen protection and adding the mixture to a reactor containing propylene glycol methyl ether; heating the reactor to 80°C; and heating and stirring the reactants for 8 hours to obtain the water-soluble resin. The water-soluble resin has a molecular weight of 500 and is partially crosslinked.

[0090] Compared with Example 1, Comparative Example 4 does not add nano-scale inorganic particles; Compared with Example 1, Comparative Example 5 does not add a solvent; Compared with Example 1, Comparative Example 6 does not add a flow promoter; Compared with Example 1, Comparative Example 7 does not add an ultraviolet light absorber; Compared with Example 1, Comparative Example 8 has an inorganic nanoparticle size of 100 nm.

[0091] The methods for preparing the cutting protection liquid in the above embodiments and comparative examples are similar, specifically: weighing the components in parts by mass; mixing the water-soluble resin, ultraviolet absorber, cosolvent, flow promoter, nano-scale inorganic particles, and solvent in sequence (the components not contained in the comparative example are not added), stirring continuously during the addition process, and stirring at 400 rpm for 3 hours at 40°C to obtain the cutting protection liquid.

[0092] The cutting protection liquids of Examples 1-12 and Comparative Examples 1-8 were respectively coated on the wafer surface, and the film forming performance was observed and compared. The specific results are shown in Table 3.

[0093] Table 3

[0094] Viscosity measurement method:

[0095] The viscosity was measured using a NDJ-5S rotational viscometer. The rotation speed was set to 100 rpm for viscosities between 20 and 50; 50 rpm for viscosities between 50 and 100; and 10 rpm for viscosities between 100 and 200.

[0096] Film thickness measurement method:

[0097] After obtaining the cutting protection liquid of each of the above-mentioned embodiments and comparative examples, 35 to 40 mL of the protection liquid was dropped onto a 12-inch silicon wafer, and then a spin coater was used to coat the silicon wafer at a spin coating speed of 100 to 1500 rpm. The coating time was 120 s to uniformly coat the silicon wafer and dry it into a film. The thickness of the film layer of each embodiment was adjusted by adjusting the spin coating speed of the spin coater. The film thickness was measured using a KLA F50UV film thickness meter, and the sample was precisely positioned under the probe to prepare for measurement (100 points were measured on each wafer). Among them, the film thickness difference is the difference between the maximum film thickness and the minimum film thickness on the same silicon wafer, which reflects the uniformity of the film layer after coating.

[0098] Solubility test method:

[0099] Place 75g of room-temperature deionized water in a 40°C water bath and stir. Slowly add 25g of resin at a stirring rate of 200 rpm / min for 10 minutes. Observe the solution for clarity and the presence of solid particles.

[0100] High temperature resistance test:

[0101] Heat the cutting fluid to 200°C for 20 minutes, then spin-coat it on a silicon wafer to see if it can be washed off with water.

[0102] As can be seen from Table 3, the film thickness of Examples 1-12 is all above 4.5 μm, the film thickness difference is all within 0.4 μm, and the viscosity is all below 80 cP, which meets the requirements of lower viscosity for thicker film layers and good film thickness uniformity. Comparative Examples 1-6 and Comparative Example 8 do not meet the above requirements. Comparative Example 2 does not add a cross-linking agent, resulting in very poor high temperature resistance; in Comparative Example 3, the mass ratio of monomer to cross-linking agent is 150:0.1, and the amount of cross-linking agent added is small, resulting in poor high temperature resistance; Comparative Example 4 does not add nano-scale inorganic particles, resulting in poor film density; Comparative Example 7 does not add a UV absorber, which will affect the cutting performance and produce a large amount of slag.

[0103] Further referring to Figures 2 and 3, Figure 2 shows a photo of the wafer after coating using Example 1. From Figure 2, it can be seen that the morphology of the wafer after coating is good and the film thickness is basically consistent. Figure 3 shows a photo of the wafer after coating using Comparative Example 1. From Figure 3, it can be seen that the morphology of the wafer after coating is poor, the film thickness difference is large, and the film layer is uneven.

[0104] The above is a detailed introduction to a plasma cutting protective liquid, a preparation method and an application thereof provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A plasma cutting protection liquid, wherein: The composition comprises the following components, calculated by mass: 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanometer-sized inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber, and 50 to 100 parts of a solvent; Wherein, the water-soluble resin contains an amide group, and the water-soluble resin is a partially cross-linked resin.

2. The plasma cutting protection liquid according to claim 1, wherein: The water-soluble resin is prepared by polymerization of a reactive monomer and a cross-linking agent; wherein the reactive monomer is a compound containing a double bond and the amide group, and the cross-linking agent is a compound containing a bifunctional group.

3. The plasma cutting protection liquid according to claim 2, wherein: The mass ratio of the reactive monomer to the cross-linking agent is 60-120:0.2-0.

5.

4. The plasma cutting protection liquid according to claim 2, wherein: The reactive monomer is selected from at least one of acrylamide, methacrylamide, N-isopropylacrylamide, N-vinylacetamide, N-hydroxymethylacrylamide, and N,N-dimethylacrylamide.

5. The plasma cutting protection liquid according to claim 2, wherein: The crosslinking agent is selected from at least one of ethylene glycol diacrylate, N,N'-methylenebisacrylamide, and bis(methyl methacrylate)diisopropoxysilane.

6. The plasma cutting protection liquid according to claim 1, wherein: The molecular weight of the water-soluble resin is 1000-3000.

7. The plasma cutting protection liquid according to claim 1, wherein: The nano-scale inorganic particles are selected from at least one of Al2O3, Fe2O3, ZnO, TiO2, ZrO, SiO2 and montmorillonite.

8. The plasma cutting protection liquid according to claim 7, wherein: The average particle size of the nano-scale inorganic particles is 1 to 50 nm.

9. The plasma cutting protection liquid according to claim 1, wherein: The cosolvent is selected from at least one of nicotinamide, acetamide and carbonamide.

10. The plasma cutting protection liquid according to claim 1, wherein: The flow promoter is selected from reactive acrylic leveling agents.

11. The plasma cutting protection liquid according to claim 1, wherein: The solvent is selected from at least one of water, alcohol and ether.

12. The plasma cutting protection liquid according to claim 1, wherein: The ultraviolet light absorber is selected from at least one of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, N-(2-ethoxyphenyl)-N'-(4-ethylphenyl)-oxalamide, 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid sodium, 2-cyano-3,3-diphenylacrylate-2-ethylhexyl ester, and o-nitroaniline.

13. A method for preparing the plasma cutting protection liquid according to any one of claims 1 to 12, wherein: The following steps are involved: 8 to 40 parts of a water-soluble resin, 1 to 10 parts of a cosolvent, 0.1 to 8 parts of nanometer-sized inorganic particles, 0.5 to 3 parts of a flow promoter, 0.1 to 0.5 parts of an ultraviolet light absorber and 50 to 100 parts of a solvent are weighed, mixed, heated and stirred to obtain a plasma cutting protection liquid.

14. Use of the plasma cutting protection liquid according to any one of claims 1 to 12 in wafer cutting, wherein: The size of the wafer is 4 to 12 inches.

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