Plasma cutting protection liquid and preparation method and application thereof

Abstract

The application discloses a kind of plasma cutting protection fluid and its preparation method and application, including: 8-40 parts of water-soluble resin, 1-10 parts of cosolvent, 0.1-8 parts of nanometer inorganic particle, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber and 50-100 parts of solvent by mass fraction;Wherein, water-soluble resin contains amide group, and water-soluble resin is partially crosslinked resin.The application uses the resin containing amide group and partially crosslinked, the structure of partially crosslinked can form three-dimensional network structure to inhibit molecular motion to reach the purpose of improving high temperature resistance, resin contains a large number of hydrophilic amide group, very easy to form hydrogen bond with water, after cutting process is completed, so that the film layer formed by protection fluid can be easily removed, cleaning process is simple;Inorganic particle can further improve the heat resistance temperature of cutting protection fluid, also can increase the density of film layer, it is beneficial to form uniform film layer.

Description

Technical Field

[0001] This application belongs to the field of semiconductor cutting technology, specifically relating to a cutting protective liquid, its preparation method, and its application. Background Technology

[0002] After forming integrated circuits on semiconductor wafers (also known as substrates), the wafers are then diced to obtain semiconductor device components. The dicing method is sawing, which can cut a large number of wafers in a short time. However, if the feeding speed of the dicing increases significantly, the possibility of chip edge peeling increases, greatly reducing product yield. Based on this, methods such as ionized gas discharge to generate high-temperature plasma on the material and then using its high energy to cut the material has emerged. However, plasma cutting has high requirements. Before plasma cutting, a cutting protective solution needs to be coated on the wafer surface to form a protective film. After that, grooves are cut into the protective film using a laser, and then the wafer is completely cut by plasma. Therefore, the plasma cutting protective solution also needs to have a certain degree of laser absorption. Especially for the film layer formed by the cutting protective solution, the plasma cutting protective solution must balance high-temperature resistance, film thickness, and film uniformity; otherwise, the yield and productivity in the semiconductor wafer manufacturing process cannot be guaranteed. Summary of the Invention

[0003] Purpose of application: This application provides a plasma cutting protective fluid, 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.

[0004] Technical solution: This application provides a plasma cutting protective liquid, which, by weight, comprises the following components: 8-40 parts of water-soluble resin, 1-10 parts of co-solvent, 0.1-8 parts of nano-sized inorganic particles, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber, and 50-100 parts of solvent.

[0005] The water-soluble resin contains amide groups and is a partially cross-linked resin.

[0006] In some embodiments, the water-soluble resin is prepared by polymerization of a reactive monomer and a crosslinking agent; wherein the reactive monomer is a compound containing a double bond and an amide group, and the crosslinking agent is a compound containing a bifunctional group.

[0007] In some embodiments, the mass ratio of the reactive monomer to the crosslinking agent is 60–120:0.2–0.5.

[0008] 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; and / or the crosslinking agent is selected from at least one of ethylene glycol diacrylate, N,N'-methylenebisacrylamide, and bis(methyl methacrylate)diisopropoxysilane.

[0009] In some embodiments, the molecular weight of the water-soluble resin is 1000 to 3000.

[0010] In some embodiments, 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 1–50 nm.

[0011] In some embodiments, the co-solvent is selected from at least one of nicotinamide, acetamide, and carbamide; and / or

[0012] The flow promoter is selected from reactive acrylate leveling agents; and / or

[0013] The solvent is selected from at least one of water, alcohol, and ether.

[0014] In some embodiments, the ultraviolet absorber is selected from at least one of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, N-(2-ethoxyphenyl)-N'-(4-ethylphenyl)-ethylenediamide, sodium 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid, 2-cyano-3,3-diphenylacrylate-2-ethylhexyl ester, and o-nitroaniline.

[0015] In some embodiments, this application also provides a method for preparing a plasma cutting protective fluid, comprising the following steps:

[0016] Under a protective atmosphere, the reactive monomers, crosslinking agents, and initiators are mixed, heated, stirred, and reacted to prepare a water-soluble resin.

[0017] Weigh 8-40 parts of water-soluble resin, 1-10 parts of co-solvent, 0.1-8 parts of nano-sized inorganic particles, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber, and 50-100 parts of solvent, mix, heat, and stir to obtain plasma cutting protective fluid.

[0018] In some embodiments, this application also provides the application of plasma cutting protective fluid in wafer cutting, wherein the wafer size is 4 to 12 inches.

[0019] Compared with the prior art, the beneficial effects of this application are as follows: The plasma cutting protective liquid of this application, by weight, comprises the following components: 8-40 parts of water-soluble resin, 1-10 parts of co-solvent, 0.1-8 parts of nano-sized inorganic particles, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber, and 50-100 parts of solvent; wherein, the water-soluble resin contains amide groups, and the water-soluble resin is a partially cross-linked resin. The cutting protective fluid of this 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 and improve high-temperature resistance. The resin contains a large number of hydrophilic amide groups, which readily form hydrogen bonds with water. After the cutting process, the film formed by the protective fluid can be easily removed, simplifying the cleaning process. At the same time, the nano-sized inorganic particles can further improve the heat resistance temperature of the cutting protective fluid and increase the density of the film, which is beneficial for forming a uniform film. This application provides a protective fluid that is suitable for both laser cutting and plasma cutting, which can improve the yield and productivity in the semiconductor manufacturing process.

[0020] It is understood that, compared with the prior art, the preparation method of the plasma cutting protective fluid and the application of the plasma cutting protective fluid provided in this application have all the technical features and beneficial effects of the plasma cutting protective fluid, and will not be repeated here. Attached Figure Description

[0021] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0022] Figure 1 The infrared spectrum of the water-soluble resin prepared in Example 1 is shown below.

[0023] Figure 2 These are images of the wafer surface after the cutting protective liquid prepared in Example 1 has been applied.

[0024] Figure 3 This is an image of the cutting protective solution prepared using Comparative Example 1 after being coated onto the wafer surface. Detailed Implementation

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] In the description of this application, it should be noted that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0027] The following disclosure provides many different implementations or examples for carrying out different structures of this application. To simplify the disclosure of this application, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit this application.

[0028] Semiconductors are materials whose electrical conductivity at room temperature falls between that of conductors and insulators. Semiconductors are used in integrated circuits, consumer electronics, communication systems, photovoltaic power generation, lighting, and high-power power conversion, among other fields. For example, diodes are devices made using semiconductors. The core components of most electronic products, such as computers, mobile phones, and digital recorders, are closely related to semiconductors.

[0029] Common semiconductor materials include silicon, germanium, and gallium arsenide, with silicon being the most influential in various semiconductor applications. After integrated circuits are formed on a wafer (also called a substrate) composed of semiconductor materials, the wafer is then diced. Dicing methods include sawing, which has always been the most widely used dicing method. Its biggest advantage is that it can cut a large number of wafers in a short time. However, if the dicing feed speed increases significantly, the possibility of chip edge breakage increases, greatly reducing product yield. Furthermore, as chip sizes become smaller and precision increases, sawing is far from meeting the dicing requirements.

[0030] Plasma cutting has emerged as a solution, and it can be broadly categorized into coating, cutting, and cleaning. Plasma cutting utilizes methods such as ionized gas discharge to generate high-temperature plasma on materials, using this high energy to cut them. During this process, the plasma generates a significant amount of heat, so the final protective film layer of the plasma cutting solution must possess excellent high-temperature resistance. During plasma cutting, the plasma etches not only the exposed cutting path but also the protective film layer coated with the cutting solution. If the film layer thickness is insufficient, the protective film layer is etched away before the plasma completes the cutting path. After the film layer is etched away, the plasma continues to etch the chip, causing irreversible damage. Therefore, the plasma cutting protective film layer needs to be sufficiently thick. Furthermore, film layer uniformity is also crucial. To ensure uniformity, the viscosity of the protective solution must not be too high. Lower viscosity increases the fluidity of the protective solution, improving leveling properties and making it easier to form a uniform film layer. Wafer sizes include 4-inch, 6-inch, 8-inch, and 12-inch. As the wafer size increases, uniform coating becomes more difficult, especially for 12-inch wafers, which are the most difficult to coat. For 12-inch wafers, simply reducing the viscosity cannot guarantee the coating effect.

[0031] Therefore, there is a need to provide a plasma cutting protective fluid to solve the above problems.

[0032] This application provides a plasma cutting protective liquid, comprising the following components by weight: 8-40 parts of water-soluble resin, 1-10 parts of co-solvent, 0.1-8 parts of nano-sized inorganic particles, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber, and 50-100 parts of solvent; wherein the water-soluble resin contains amide groups and is a partially cross-linked resin.

[0033] In some embodiments, the plasma cutting protective fluid, by weight, further preferably comprises: 10-35 parts of water-soluble resin, 2-8 parts of co-solvent, 0.3-6 parts of nano-sized inorganic particles, 0.5-2 parts of flow promoter, 0.15-0.45 parts of ultraviolet absorber, and 60-90 parts of solvent.

[0034] In some embodiments, the plasma cutting protective fluid, by weight, further preferably comprises: 15-30 parts of water-soluble resin, 3-6 parts of co-solvent, 0.5-5 parts of nano-sized inorganic particles, 0.5-1.5 parts of flow promoter, 0.2-0.4 parts of ultraviolet light absorber, and 70-85 parts of solvent.

[0035] Understandably, the cutting protective fluid 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 and improve high-temperature resistance. The resin contains a large number of hydrophilic amide groups, which readily form hydrogen bonds with water. After the cutting process is completed, the film formed by the protective fluid can be easily removed, and the cleaning process is simple.

[0036] Furthermore, although the water solubility and washability of the resin will decrease after cross-linking, the resin in this embodiment is partially cross-linked. Therefore, the uncross-linked water-soluble resin and the cross-linked resin coexist. After film formation, the uncross-linked part is a washable part, which can wash away the cross-linked part that is difficult to wash away.

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

[0038] Understandably, the double bonds in the reactant monomer can react with the crosslinking agent to form crosslinking points, thereby further obtaining a three-dimensional network structure to improve the high-temperature resistance of the cutting protective fluid. Furthermore, the crosslinked resin exhibits improved film-forming properties because the three-dimensional network structure enhances the intermolecular interactions, allowing the molecules to more tightly bond to the wafer surface during film formation, thus improving the film's strength and stability. The degree of crosslinking can be determined using differential thermal analysis, nuclear magnetic resonance (NMR), etc. The resin contains a large number of hydrophilic amide groups, which readily form hydrogen bonds with water, enabling the protective fluid film to be easily removed after the cutting process, simplifying the cleaning process. The bifunctional groups in the crosslinking agent can form more crosslinking points, increasing the density of partial crosslinking. This allows the resin to form a tighter network structure, increasing the intermolecular interactions and improving thermal stability and high-temperature resistance.

[0039] In some embodiments, the reactive monomers are 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 for acrylamide is 79-06-1, for methacrylamide it is 79-39-0, for N-isopropylacrylamide it is 2210-25-5, for N-vinylacetamide it is 5202-78-8, for N-hydroxymethylacrylamide it is 924-42-5, and for N,N-dimethylacrylamide it is 2680-03-7. All of the above reactive monomers are commercially available 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. All of the above crosslinking agents are commercially available and will not be described in detail here.

[0041] In some embodiments, the molecular weight of the water-soluble resin is between 1000 and 3000. For example, the molecular weight of the water-soluble resin can be any one or any two of 1000, 1500, 2000, 2500, and 3000. A smaller molecular weight of the water-soluble resin results in lower viscosity, which helps to increase the solid content and leads to a thicker film. Too small a molecular weight results in poor heat resistance, while too large a molecular weight leads to higher overall viscosity and poor film uniformity. Therefore, by controlling the polymerization conditions to achieve a molecular weight of 1000 to 3000 for the water-soluble resin, excellent film-forming properties are achieved within this range, forming a complete protective film on the substrate surface. This allows for the preparation of a high-thickness protective liquid at a lower viscosity, while also improving the resin's heat resistance while maintaining water solubility.

[0042] In some embodiments, the degree of crosslinking refers to the extent to which the polymer or resin is crosslinked (chemically bonded). In resins with a high degree of crosslinking, the crosslinking structure between polymer chains is more compact, resulting in a three-dimensional network structure.

[0043] In some embodiments, 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 1–50 nm. It is understood that nanoscale inorganic particles can further improve the heat resistance temperature of the cutting protective fluid, increase the density of the film, enhance its etching resistance, increase the etching selectivity, and ensure that the substrate is not damaged during etching. The smaller the average particle size of the nanoscale inorganic particles, the better the modification effect, the more uniformly and stably they can be dispersed in the solution, and the more conducive it is to the formation of a uniform film. The nanoscale inorganic particles are made of inorganic materials with a temperature resistance above 1000℃; the smaller the particle size, the more uniformly and stably they are dispersed, and the better they can fill the gaps in the film, improving the density of the film.

[0044] In some embodiments, the average particle size of the nanoscale inorganic particles is 1–50 nm. For example, it can be any one or a range between any two values ​​from 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. More preferably, the average particle size of the nanoscale inorganic particles is 1–20 nm.

[0045] In some embodiments, the nanoscale inorganic particles are preferably SiO2 and / or montmorillonite, with montmorillonite having CAS number 1318-93-0.

[0046] In some embodiments, the cosolvent is selected from at least one of nicotinamide, acetamide, and carbamate. It is understood that the cosolvent can form soluble intermolecular complexes, associations, etc., with the partially cross-linked, poorly soluble resin in a solvent, thereby increasing the solubility of the partially cross-linked resin in the solvent. The cosolvent is soluble in water and is mostly a low-molecular-weight compound. The cosolvent is selected based on the properties of the substance and its ability to form water-soluble intermolecular complexes, double salts, or associations. Preferred cosolvents are nicotinamide, acetamide, etc., because they all have amide groups and similar structures to the resin. Based on the principle of "like dissolves like," the cosolvent and the polymerized resin have excellent compatibility, resulting in excellent stability of the protective solution and easier formation of a uniform and stable film.

[0047] In some embodiments, the flow promoter is selected from reactive acrylate leveling agents. For example, the flow promoter is selected from at least one of the grades 1073 and 1074 of Monen Chemical, which has the characteristics of good compatibility and excellent slip properties; or, any one of the products synde-124, synde-125, and synde-126 produced by Zhuhai Xiande can also be selected; wherein, synde-124 and synde-125 are acrylate copolymers, and synde-126 is a fluorocarbon modified polyacrylate leveling agent; all three have many advantages such as improving leveling and flowability, not affecting recoatability and interlayer adhesion, and preventing defects such as pinholes, craters, and fisheyes in the coating film.

[0048] In some embodiments, the solvent is selected from at least one of water, alcohol, and ether. The water is deionized water; the alcohol may be, for example, any one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, and isobutanol; the ether may be, for example, any one or more of diethyl ether, methyl ethyl ether, di-n-butyl ether, propylene glycol methyl ether, and ethylene glycol propyl ether. Preferably, it is deionized water, isopropanol, propylene glycol methyl ether, or any combination of these substances; most preferably, it is a combination of deionized water and propylene glycol methyl ether.

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

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

[0051] Under a protective atmosphere, the reactive monomers, crosslinking agents, and initiators are mixed, heated, stirred, and reacted to prepare a water-soluble resin.

[0052] Weigh 8-40 parts of water-soluble resin, 1-10 parts of co-solvent, 0.1-8 parts of nano-sized inorganic particles, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber, and 50-100 parts of solvent, mix, heat, and stir to obtain plasma cutting protective fluid.

[0053] In some embodiments, the mass ratio of the reactive monomer to the crosslinking agent is 60–120:0.2–0.5. For example, a preferred ratio is 100:0.3.

[0054] In some embodiments, the amount of initiator is 0.2-1.5 parts, preferably 0.5-1 parts, and most preferably 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 200-500 rpm, for example, 300 rpm, 400 rpm, or 500 rpm. The stirring time is 1-5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours.

[0057] In some embodiments, the plasma cutting protective fluid provided in this embodiment can be used in wafer cutting, wherein the wafer size 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 the spin coating program, drop 35-40 mL of the cutting protection solution of this embodiment onto the wafer, 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 above-described dicing protective liquid can adapt to various wafer structures, forming a protective film on the wafer surface to ensure that the wafer is not scratched by fragments during dicing, thereby improving the yield of semiconductor products and the efficiency of dicing. The protective liquid agent of this application has very good application prospects and large-scale industrial promotion potential in the field of semiconductor dicing protection.

[0063] Cutting protective fluids for Examples 1-12 are provided respectively, and the specific components are shown in Table 1.

[0064] Table 1

[0065]

[0066]

[0067] Example 1

[0068] In Table 1, the water-soluble resin of Example 1 was prepared by reacting N,N-dimethylacrylamide and ethylene glycol diacrylate. The preparation method was as follows: Under nitrogen protection, N,N-dimethylacrylamide and ethylene glycol diacrylate in a mass ratio of 100:0.3 and 0.8 parts of azobisisobutyronitrile were mixed and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, the water-soluble resin was obtained. The molecular weight of the water-soluble resin was 2000, and the water-soluble resin was partially cross-linked; the degree of partial cross-linking was determined by the mass ratio.

[0069] See Figure 1 The image shows the infrared spectrum of the water-soluble resin prepared after the reaction of N,N-dimethylacrylamide and ethylene glycol diacrylate. Figure 1 The 1650cm peak can be seen in the spectrum. -1 With 1350cm -1 Characteristic peak of amide group; 1723 cm⁻¹ -1 This is the carbonyl C=O stretching vibration; 3004 cm⁻¹ -1 2965cm -1 2926cm -1 The stretching vibration of -CH3, 1421 cm. -1 and 1362cm -1 The bending vibration of -CH3 indicates that a partially cross-linked water-soluble resin was successfully synthesized.

[0070] Example 2

[0071] In Table 1, the water-soluble resin of Example 2 was prepared by reacting N,N-dimethylacrylamide and N,N'-methylenebisacrylamide. The preparation method was as follows: Under nitrogen protection, N,N-dimethylacrylamide and N,N'-methylenebisacrylamide in a mass ratio of 60:0.5 and 0.2 parts of azobisisobutyronitrile were mixed and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, the water-soluble resin was obtained. The molecular weight of the water-soluble resin was 3000, and the water-soluble resin was partially cross-linked; the degree of partial cross-linking was determined by the mass ratio.

[0072] Example 3

[0073] In Table 1, the water-soluble resin of Example 3 was prepared by reacting N,N-dimethylacrylamide and ethylene glycol diacrylate. The preparation method was as follows: Under nitrogen protection, N,N-dimethylacrylamide and ethylene glycol diacrylate in a mass ratio of 120:0.2 and 1.5 parts of azobisisobutyronitrile were mixed and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, the water-soluble resin was obtained. The molecular weight of the water-soluble resin was 2500, and the water-soluble resin was partially cross-linked; the degree of partial cross-linking was determined by the mass ratio.

[0074] Example 4

[0075] In Table 1, the water-soluble resin of Example 4 was prepared by reacting N,N-dimethylacrylamide and ethylene glycol diacrylate. The preparation method was as follows: Under nitrogen protection, N,N-dimethylacrylamide and ethylene glycol diacrylate in a mass ratio of 100:0.4 and 0.5 parts of azobisisobutyronitrile were mixed and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, the water-soluble resin was obtained. The molecular weight of the water-soluble resin was 1500, and the water-soluble resin was partially cross-linked; the degree of partial cross-linking was determined by the mass ratio.

[0076] Example 5

[0077] In Table 1, the water-soluble resin of Example 5 was prepared by reacting N,N-dimethylacrylamide and N,N'-methylenebisacrylamide. The preparation method was as follows: Under nitrogen protection, N,N-dimethylacrylamide and N,N'-methylenebisacrylamide in a mass ratio of 80:0.3 and 1 part of azobisisobutyronitrile were mixed and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, the water-soluble resin was obtained. The molecular weight of the water-soluble resin was 2000, and the water-soluble resin was partially cross-linked; the degree of partial cross-linking was determined by the mass ratio.

[0078] Example 6

[0079] In Table 1, the water-soluble resin of Example 6 was prepared by reacting N,N-dimethylacrylamide and bis(methyl methacrylate)diisopropoxysilane. The preparation method was as follows: Under nitrogen protection, N,N-dimethylacrylamide and bis(methyl methacrylate)diisopropoxysilane in a mass ratio of 120:0.5 and 1.2 parts of azobisisobutyronitrile were mixed and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, the water-soluble resin was obtained. The molecular weight of the water-soluble resin was 1000, and the water-soluble resin was partially cross-linked; the degree of partial cross-linking was determined by the mass ratio.

[0080] Examples 7-12

[0081] The water-soluble resin in Example 7 was prepared by reacting acrylamide and ethylene glycol diacrylate, using the same preparation method as in Example 1.

[0082] The water-soluble resin in Example 8 was prepared by reacting N-isopropylacrylamide and ethylene glycol diacrylate, using the same preparation method as in Example 1.

[0083] The water-soluble resin in Example 9 was prepared by reacting N-vinylacetamide and ethylene glycol diacrylate, using the same preparation method as in Example 1.

[0084] The water-soluble resin of Example 10 was prepared by reacting N-hydroxymethylacrylamide and ethylene glycol diacrylate, and the preparation method was the same as that of Example 1.

[0085] The water-soluble resin in Example 11 was prepared by reacting methacrylamide and ethylene glycol diacrylate, using the same preparation method as in Example 1.

[0086] The water-soluble resin in Example 12 was prepared by reacting N-vinylacetamide and ethylene glycol diacrylate, using the same preparation method as in Example 1.

[0087] Cutting protective fluids are provided for comparative examples 1-8; see Table 2 for specific components.

[0088] Table 2

[0089]

[0090]

[0091]

[0092] 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 in Comparative Example 1 was prepared as follows: Under nitrogen protection, N,N-dimethylacrylamide, ethylene glycol diacrylate, and 0.8 parts of azobisisobutyronitrile were mixed in a mass ratio of 50:1 and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, a non-water-soluble resin was obtained. The non-water-soluble resin had a molecular weight of 5000 and was partially soluble in water.

[0093] The only difference between Comparative Example 2 and Example 1 is that the degree of crosslinking of the water-soluble resin is different. Specifically, the preparation method of the water-soluble resin in Comparative Example 2 is as follows: no crosslinking agent is added, and at this time, it is impossible to obtain a water-soluble resin with a certain degree of crosslinking.

[0094] The only difference between Comparative Example 3 and Example 1 is the degree of crosslinking of the water-soluble resin. Specifically, the water-soluble resin in Comparative Example 3 was prepared as follows: Under nitrogen protection, N,N-dimethylacrylamide, ethylene glycol diacrylate, and 0.8 parts of azobisisobutyronitrile were mixed in a mass ratio of 150:0.1 and added to a reaction vessel containing propylene glycol methyl ether; the reaction vessel was heated to 80°C; the reaction mixture was heated and stirred, and after 8 hours, the water-soluble resin was obtained. The molecular weight of the water-soluble resin was 500, and the water-soluble resin was partially crosslinked.

[0095] Compared with Example 1, Comparative Example 4 did not contain nanoscale inorganic particles; Comparative Example 5 did not contain a cosolvent; Comparative Example 6 did not contain a flow promoter; Comparative Example 7 did not contain an ultraviolet absorber; Comparative Example 8 had inorganic nanoparticles with a particle size of 100 nm compared with Example 1.

[0096] The methods for preparing the cutting protective fluid in the above embodiments and comparative examples are similar, specifically as follows: weigh the respective components by mass; sequentially mix the water-soluble resin, ultraviolet absorber, cosolvent, flow promoter, nano-sized inorganic particles, and solvent (components not present in the comparative examples are not added), continuously stir during the addition process, and stir at 400 rpm for 3 hours at 40°C to obtain the cutting protective fluid.

[0097] The cutting protective solutions of Examples 1-12 and Comparative Examples 1-8 were coated on the wafer surface, and the film formation performance was observed and compared. The specific results are shown in Table 3.

[0098] Table 3

[0099]

[0100]

[0101] Viscosity measurement method:

[0102] The NDJ-5S rotational viscometer was used for measurement. For viscosity ranges of 20-50, the rotation speed was set to 100 rpm; for viscosity ranges of 50-100, the rotation speed was set to 50 rpm; and for viscosity ranges of 100-200, the rotation speed was set to 10 rpm.

[0103] Film thickness measurement method:

[0104] After obtaining the cutting protective solutions for the above embodiments and comparative examples, 35-40 mL of the protective solution was dropped onto a 12-inch silicon wafer. Then, a spin coater was used to coat the wafer at a speed of 100-1500 rpm for 120 seconds to ensure uniform coating, followed by drying to form a film. The film thickness of each embodiment was adjusted by changing the spin coater speed. A KLA F50UV film thickness gauge was used to measure the film thickness. The sample was precisely positioned under the probe for measurement (100 points per wafer). The film thickness difference is the difference between the maximum and minimum film thickness on the same silicon wafer, reflecting the uniformity of the coated film.

[0105] Solubility test method:

[0106] 75g of room temperature deionized water was placed in a 40℃ water bath and stirred while slowly adding 25g of resin. The stirring speed was 200rpm / min, and the stirring time was 10min. Observe whether the solution is transparent and clear, and whether there are any solid particles.

[0107] High temperature resistance test:

[0108] Heat the cutting fluid to 200°C and hold for 20 minutes, then spin-coat it onto a silicon wafer to see if it can be washed off with water.

[0109] As shown in Table 3, the film thicknesses of Examples 1-12 are all above 4.5 μm, the thickness differences are all within 0.4 μm, and the viscosities are all below 80 cP, meeting the requirements of relatively thick film layers with low viscosity and good film thickness uniformity. Comparative Examples 1-6 and Comparative Example 8 do not meet the above requirements. Comparative Example 2 did not add a crosslinking agent, resulting in very poor high-temperature resistance; in Comparative Example 3, the mass ratio of monomer to crosslinking agent was 150:0.1, and the amount of crosslinking agent added was small, resulting in poor high-temperature resistance; Comparative Example 4 did not add nano-sized inorganic particles, resulting in poor film density; and Comparative Example 7 did not add a UV absorber, which would affect cutting performance and generate a large amount of slag.

[0110] See further Figure 2 and Figure 3 , Figure 2 These are images after coating using Example 1, from... Figure 2 As can be seen, the wafer has a good morphology after coating, and the film thickness is basically consistent. Figure 3 This is an image after coating using Comparative Example 1, from... Figure 3It can be seen that the wafer has a poor morphology after coating, with a large difference in film thickness and uneven film layer.

[0111] The above provides a detailed description of a plasma cutting protective fluid, its preparation method, and its application, as provided in the embodiments of this application. Specific examples have been used in this application to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A plasma cutting protective fluid, characterized in that, By weight, it comprises the following components: 8-40 parts of water-soluble resin, 1-10 parts of co-solvent, 0.1-8 parts of nano-sized inorganic particles, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber and 50-100 parts of solvent. The water-soluble resin is a partially cross-linked resin obtained by polymerization of reactive monomers and a cross-linking agent. The reactive monomers are selected from at least one of acrylamide, methacrylamide, N-isopropylacrylamide, N-vinylacetamide, N-hydroxymethylacrylamide, and N,N-dimethylacrylamide; the cross-linking agent is selected from at least one of ethylene glycol diacrylate, N,N'-methylenebisacrylamide, and ethylene glycol dimethacrylate; the mass ratio of the reactive monomers to the cross-linking agent is 60~120:0.2~0.

5. The molecular weight of the water-soluble resin is 1000~3000; The co-solvent is selected from at least one of nicotinamide, acetamide, and carbamide.

2. The plasma cutting protective fluid according to claim 1, characterized in that, 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 1~50nm.

3. The plasma cutting protective fluid according to claim 1, characterized in that, The flow promoter is selected from reactive acrylate leveling agents.

4. The plasma cutting protective fluid according to claim 1, characterized in that, The solvent is selected from at least one of water, alcohol, and ether.

5. The plasma cutting protective fluid according to claim 1, characterized in that, The ultraviolet absorber is selected from at least one of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, N-(2-ethoxyphenyl)-N'-(4-ethylphenyl)-ethylenediamide, sodium 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid, 2-cyano-3,3-diphenylacrylate-2-ethylhexyl ester, and o-nitroaniline.

6. The plasma cutting protective fluid according to claim 1, characterized in that, By weight, the plasma cutting protective fluid comprises the following components: 10-35 parts of water-soluble resin, 2-8 parts of co-solvent, 0.3-6 parts of nano-sized inorganic particles, 0.5-2 parts of flow promoter, 0.15-0.45 parts of ultraviolet light absorber, and 60-90 parts of solvent.

7. A method for preparing a plasma cutting protective fluid according to any one of claims 1-5, characterized in that, Includes the following steps: Weigh 8-40 parts of water-soluble resin, 1-10 parts of co-solvent, 0.1-8 parts of nano-sized inorganic particles, 0.5-3 parts of flow promoter, 0.1-0.5 parts of ultraviolet light absorber, and 50-100 parts of solvent, mix, heat, and stir to obtain plasma cutting protective fluid.

8. The application of the plasma cutting protective fluid according to any one of claims 1-6 in wafer cutting, characterized in that, The wafers are 4 to 12 inches in size.

Images