A plasma cutting spray protection liquid and its preparation method and application

Abstract

This invention relates to a plasma cutting protective coating, comprising, by weight, the following components: 5-20 parts PSS-NVA resin; 0.1-5 parts leveling agent; 0.1-5 parts light absorber; 20-50 parts organic solvent; and 40-70 parts ultrapure water. The preparation and application methods of this cutting protective coating are also disclosed. The plasma cutting protective coating of this invention contains low molecular weight PSS-NVA resin, resulting in a low viscosity. It can form a uniform and dense protective film through ultrasonic spraying, and the film is stable after formation, not prone to cracking, has good water solubility, and can be easily removed by washing, leaving no residue on the wafer surface.

Description

Technical Field

[0001] This invention belongs to the field of plasma cutting technology, and particularly relates to a plasma cutting spray protective liquid, its preparation method and application. Background Technology

[0002] Plasma cutting protective solutions are functional chemicals used in the semiconductor industry for wafer dicing processes. Their basic functions are divided into two parts according to the dicing process: first, to protect the sides of the dicing path during laser grooving, preventing debris splashes or high temperatures from affecting functional areas and causing integrated circuit failure; second, to protect the wafer outside the dicing path from etching during plasma etching. With the rapid development of semiconductor packaging, some wafers have solder bumps or spikes 30-200μm high. The tops and surrounding areas of these bumps are very smooth. Under the influence of gravity, protective solutions applied via spin coating are difficult to form a uniform film on the bump tops or spikes, failing to protect the exposed bumps or spikes during plasma etching and potentially damaging the etched circuitry.

[0003] Ultrasonic spraying is a coating method based on ultrasonic atomizing nozzle technology. It uses an ultrasonic atomizing device to atomize a protective liquid into fine particles, which are then uniformly coated onto the substrate surface with a certain amount of carrier gas, forming a protective film. Compared to traditional spin coating, ultrasonic spraying offers greater flexibility and controllability. The coating thickness can be controlled between tens of nanometers and several micrometers, exhibiting better uniformity and precision. It can form a uniform and effective coverage on high-bump domes and sides, significantly improving plasma cutting yield.

[0004] Protective solutions used in ultrasonic spraying often require low viscosity. However, commonly used water-soluble polymers such as PVP and PVA struggle to maintain high film thicknesses at low viscosity, necessitating the use of low molecular weight resins. Sodium polystyrene sulfonate (PSS), a polymer with good water solubility and heat resistance, can provide plasma protective solutions with high etching ratios and good washability. However, commercially available PSS has a high molecular weight, making it difficult to obtain low-viscosity solutions at high solids content ratios. Furthermore, PSS's rigid structure makes it prone to cracking after curing.

[0005] Therefore, a protective liquid with lower viscosity is needed to solve the problem that existing protective liquids are not easy to maintain a high film thickness at low viscosity and are prone to cracking after film formation. Summary of the Invention

[0006] The technical problem solved by this invention is that in the prior art, plasma cutting spray protective liquid is not easy to maintain a high film thickness under low viscosity conditions, and the film is prone to cracking after formation.

[0007] In view of the technical problems existing in the prior art, the present invention designs a plasma cutting spray protective liquid containing low molecular weight PSS-NVA resin, which makes the protective liquid have low viscosity, can form a uniform and dense protective film through ultrasonic spraying, and the film is stable after formation, not easy to crack, has good water solubility, can be removed by deionized water cleaning, and leaves no residue on the wafer surface.

[0008] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition definition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," etc., and similar meanings.

[0009] To solve the aforementioned technical problems, the present invention adopts the following solution:

[0010] A plasma cutting protective coating, comprising, by weight, the following components:

[0011]

[0012] Furthermore, the PSS-NVA resin is copolymerized from sodium p-styrene sulfonate and N-vinylacetamide.

[0013] Furthermore, the polymerization method of the PSS-NVA resin includes the following steps:

[0014] Step 1: Under nitrogen protection, using ultrapure water as a solvent, stir and mix sodium styrene sulfonate, N-vinyl acetamide and ultrapure water evenly. After the above substances are completely dissolved, slowly raise the temperature to 40-60℃, and then add the initiator to react at a constant temperature for a certain period of time.

[0015] Step 2: After the reaction is complete, the temperature is lowered to below 25°C, and the copolymer is precipitated with n-butanol as a precipitant. The precipitated copolymer is washed and vacuum dried to obtain powdered PSS-NVA resin.

[0016] Furthermore, in step 1, the heating temperature is slowly increased to 50°C at a heating rate of 2°C / min, and the reaction is kept at a constant temperature for 1-10 minutes.

[0017] Furthermore, in step 2, the precipitated copolymer was washed multiple times with a mixture of anhydrous ethanol and water in a volume ratio of 4:1, and then vacuum dried at 30°C for 24 hours.

[0018] Furthermore, the average molecular weight of the PSS-NVA resin is approximately 2000-10000 g / mol.

[0019] Furthermore, the inventors discovered that the thermal decomposition temperature of the powdered PSS-NVA resin synthesized by the above method is as high as 500℃, exhibiting high etching resistance while retaining its good water solubility. In addition, by controlling the polymerization reaction time, low molecular weight (2000-10000 g / mol) polymers were obtained, thereby producing a plasma cutting spray protective liquid with high solid content, low viscosity, and high film thickness.

[0020] Furthermore, in step 1, the molar ratio of sodium styrene sulfonate to N-vinylacetamide is 8:1-10:1.

[0021] Furthermore, in step 1, the molar ratio of ultrapure water to sodium p-styrene sulfonate is 6:1-10:1.

[0022] Furthermore, in step 1, the molar ratio of the initiator to sodium p-styrenesulfonate is 0.01:1 to 0.1:1.

[0023] Furthermore, the initiator in step 1 is potassium persulfate or ammonium persulfate.

[0024] Furthermore, the leveling agent is one or more of the following: silicone, polyester, and acrylate.

[0025] Furthermore, the leveling agent is more preferably an organosilicon-based leveling agent.

[0026] Furthermore, the leveling agent is most preferably BYK-349.

[0027] Furthermore, the absorber is any one of the absorbers that has an absorption peak at 355 nm, an absorption peak at 532 nm, or an absorption peak at 1064 nm.

[0028] Furthermore, the light absorber is any one of benzophenones, benzotriazoles, salicylates, triazines, or coumarins that have an absorption peak at 355 nm; or an edible red pigment that has an absorption peak at 532 nm; or any one of azo dyes or anthraquinones that have an absorption peak at 1064 nm.

[0029] Furthermore, the absorber is preferably an absorber with an absorption peak at 355 nm.

[0030] Furthermore, the light absorber is more preferably 2,4-dihydroxybenzophenone, sodium 2,2'-dihydroxy-4,4'-dimethoxybenzophenone-5,5'-disulfonic acid, 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone, 4-diethylaminoketo acid, sodium ferulic acid, 6,7-dihydroxycoumarin, coumarin-3-carboxylic acid, N-phenyl-o-aminobenzoic acid, disodium 4,4'-bis(2-sulfonylstyryl)biphenyl (abbreviated as CBS-X), diethylhexylbutamidotriazinone (CAS No.: 154702-15-5), etc.

[0031] Furthermore, the light absorber is more preferably any one of 2,2'-dihydroxy-4,4'-dimethoxybenzophenone-5,5'-disulfonate sodium, 4,4'-bis(2-sulfonyl)biphenyl disodium (CBS-X), and sodium ferulic acid.

[0032] Furthermore, the light absorber is most preferably CBS-X.

[0033] In this invention, the light absorber is an organic compound that has an absorption peak at the slotted laser wavelength. Different light absorbers can be selected according to different laser wavelengths, such as 355nm / 532nm / 1064nm, and are not limited in this invention.

[0034] Furthermore, the organic solvent is selected from at least two of alcohols, alcohol ethers, ketones, and esters.

[0035] Further, the organic solvent is at least two of methanol, ethanol, propanol, isopropanol, propylene glycol, glycerol, diethylene glycol, propylene glycol methyl ether, propylene glycol ethyl ether, dipropylene glycol ethyl ether, glycerol methyl ether, ethylene glycol ethyl ether, glycerol ethyl ether, acetone, methyl methacrylate, butyl acrylate, and propylene glycol methyl ether acetate.

[0036] Furthermore, the organic solvent is preferably at least two selected from ethanol, isopropanol, propylene glycol, glycerol, diethylene glycol, propylene glycol methyl ether, glycerol methyl ether, acetone, and butyl acrylate.

[0037] Furthermore, the organic solvent is most preferably isopropanol, propylene glycol methyl ether, and acetone.

[0038] Furthermore, the mass ratio of isopropanol, propylene glycol methyl ether, and acetone is 5-10:5-20:10-20.

[0039] This invention also discloses a method for preparing a plasma cutting spray protective liquid, comprising the following steps:

[0040] Step 1: Weigh out the respective amounts of each component;

[0041] Step 2: Add the organic solvent and leveling agent to the container, mix well, then add ultrapure water. Add PSS-NVA resin evenly while stirring at a feeding rate of 50 parts / min, and stir at room temperature for 4 hours until it is uniform and transparent.

[0042] Step 3: Add the light absorber while stirring, continue stirring for 30 minutes until uniform and transparent, then filter and let stand to defoam, and you will get the ultrasonic spraying laser cutting protective liquid.

[0043] This invention also discloses a method for using a plasma cutting spray protective liquid, comprising the following steps:

[0044] The laser protective liquid used in the spraying process is a undiluted solution and does not require dilution. The laser protective liquid is atomized into fine particles by an ultrasonic atomizing device and coated onto the substrate surface in multiple applications to form a protective film.

[0045] Furthermore, the process parameters for spraying using an ultrasonic atomization device are as follows: a wide-width nozzle is selected, the spraying method is a fan-shaped area, the spraying operation frequency is 60kHz, the flow rate is adjusted to 0.5mL / min, the distance between the nozzle and the wafer is fixed at 60mm, the number of spraying times is at least 2, and the heating table temperature is set to 50℃.

[0046] The number of spraying times is based on the actual required film thickness, and this invention does not impose a specific limit.

[0047] Further, after spraying the plasma cutting protective solution onto the wafer surface to form a uniform protective film according to the above steps, laser grooving and plasma cutting can be performed. After chip cutting is completed, deionized water can be used to dissolve and clean away any remaining residues and stains along with the protective solution film.

[0048] The present invention also discloses the use of a plasma cutting spray protective liquid in the chip plasma cutting process.

[0049] In this invention, to further optimize the protective effect, the plasma cutting spray protective liquid can be further preferably composed of: 8-15 parts of PSS-NVA resin; 1-3.5 parts of leveling agent; 1-3.5 parts of light absorber; 30-45 parts of organic solvent; and 50-65 parts of ultrapure water.

[0050] In this invention, the preferred mass ratio of isopropanol, propylene glycol methyl ether, and acetone is 5:10:20.

[0051] In this invention, PSS-NVA resin has unique advantages:

[0052] Firstly, it has excellent high-temperature resistance, which can provide good protection during plasma gas etching, thus exhibiting a high selective etching ratio;

[0053] Secondly, PSS-NVA resins with different molecular weights can be used to prepare spray protective liquids with different solid contents, viscosities, and film thicknesses according to different spraying requirements.

[0054] Thirdly, due to its good water solubility, it can ensure that the film layer can be easily rinsed clean with deionized water after etching, leaving no residue on the wafer surface.

[0055] In this invention, the main function of the leveling agent is to help the protective liquid form a uniform and smooth protective film during the spraying process, so as to avoid unevenness caused by spraying splashes.

[0056] In this invention, the addition of organic solvents has the following advantages:

[0057] Firstly, in order to allow the protective liquid to evaporate quickly and achieve a curing effect after being sprayed onto the wafer;

[0058] Secondly, in order to retain moisture after the protective film is formed, the organic solvent needs to be mixed with multiple solvents.

[0059] This invention provides a plasma cutting spray protective liquid, its preparation method, and its application, which have the following beneficial effects. fruit :

[0060] 1. This invention synthesizes PSS-NVA resin using sodium p-styrene sulfonate and N-vinylacetamide as monomers. Because the N-vinylacetamide monomer disrupts the rigid structure of PSS, it prevents cracking after polymer film formation. Furthermore, due to the presence of its side benzenesulfonic acid groups, it also exhibits good etching resistance and water solubility, dissolving in water and facilitating the removal of slag and protective film during the cleaning process. This invention adds PSS-NVA resin to the cutting protective fluid. Due to the presence of a large number of sodium benzenesulfonate groups, this polymer exhibits good etching resistance. The amino and sodium sulfonate groups also ensure the polymer's water solubility. The low molecular weight of the polymer results in a low viscosity of the protective fluid, allowing for the formation of a uniform and dense protective film through ultrasonic spraying. Moreover, the film is stable after formation and is not prone to cracking.

[0061] 2. The present invention uses a light absorber. Because the light absorber has high light absorption, it can not only ensure the light absorption of the film layer and reduce the heat-affected zone, but also avoid the film layer from leaving residues after water washing.

[0062] 3. This invention uses a combination of ultrapure water and organic solvent as a solvent, which increases the evaporation rate of the film layer while ensuring the water content of the film layer, thus helping to improve the curing speed and the uniformity of the film layer.

[0063] 4. The present invention adopts a coating method of multiple spraying of protective liquid, which not only ensures the uniformity of the protective liquid film formation, but also reduces the amount of protective liquid used.

[0064] Therefore, the plasma cutting spray protective liquid of the present invention has very good application prospects and potential for large-scale industrial promotion in the semiconductor field. Attached Figure Description

[0065] Figure 1 : Infrared absorption spectrum of resin 1 of PSS-NVA;

[0066] Figure 2 : Thermogravimetric curve of resin 1 powder of PSS-NVA;

[0067] Figure 3 The protective film was sprayed onto the wafer surface using the protective spraying solution prepared in Example 1. Grooves were then cut and etched. After standing for 72 hours, the wafer was cleaned with deionized water and the image was magnified 50 times under a microscope.

[0068] Figure 4 The image is a 5000x magnified SEM side view of the film layer after the protective coating prepared in Example 1 was sprayed onto the surface of a silicon wafer, grooved, and etched to a depth of 100 μm.

[0069] Figure 5 The protective coating prepared in Comparative Example 2 was sprayed onto the surface of a silicon wafer, and after grooving and 100 μm deep silicon etching, the film layer was magnified 5000 times to obtain a side view image. Detailed Implementation

[0070] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0071] The polymerization method of PSS-NVA resins 1-8 of the present invention includes the following steps:

[0072] Step 1: Under nitrogen protection, using ultrapure water as a solvent, sodium styrene sulfonate, N-vinyl acetamide and ultrapure water are stirred and mixed evenly. After the above substances are completely dissolved, the temperature is slowly raised to 50°C at a heating rate of 2°C / min. Then potassium persulfate is added as an initiator and the reaction is carried out at a constant temperature for 10 min.

[0073] Step 2: After the reaction is complete, cool down to below 25°C, precipitate the copolymer with n-butanol as a precipitant, wash the copolymer multiple times with a mixture of anhydrous ethanol and water in a volume ratio of 4:1, and vacuum dry at 30°C for 24 hours to obtain powdered PSS-NVA resin.

[0074] The PSS-NVA resins 1-5 of this invention are prepared using the components listed in Table 1.

[0075] Table 1 PSS-NVA Resin 1-5

[0076]

[0077] Resin 6:

[0078] The only difference between resin 6 and resin 1 is the reaction time; resin 6 is obtained by reacting at a constant temperature for 1 minute.

[0079] Resin 7:

[0080] The only difference between resin 7 and resin 1 is the reaction time; resin 7 is obtained by reacting at a constant temperature for 5 minutes.

[0081] Resin 8:

[0082] The only difference between resin 8 and resin 1 is that N-vinylpyrrolidone is used instead of N-vinylacetamide to copolymerize poly(N-vinylpyrrolidone-co-sodium p-styrenesulfonate), abbreviated as P(NVP-CO-SSS).

[0083] The plasma cutting spray protective liquid of this invention is prepared using the components listed in Table 2, and its preparation method includes the following steps:

[0084] Step 1: Weigh out the respective amounts of each component;

[0085] Step 2: Add the organic solvent to the container, mix well, then add ultrapure water. Add PSS-NVA resin while stirring at a speed of 50 parts / min, and stir at room temperature for 4 hours until it is uniform and transparent.

[0086] Step 3: Add the light absorber while stirring, continue stirring for 30 minutes until uniform and transparent, then filter and let stand to defoam, and you will get the ultrasonic spraying laser cutting protective liquid.

[0087] Table 2 Examples 1-7

[0088]

[0089]

[0090] Table 3 Comparative Examples 1-3

[0091]

[0092]

[0093] How to use the plasma cutting spray protective liquid of this invention:

[0094] Step 1: The plasma cutting spray protective liquids prepared in Examples 1-7 and Comparative Examples 1-3 above are used as stock solutions and do not require dilution. The spray laser protective liquid is atomized into fine particles by an ultrasonic atomizing device.

[0095] Step 2: Set the spraying parameters of the ultrasonic atomization device: Select a wide-width nozzle, spraying mode is a fan-shaped area, spraying operation frequency is 60kHz, flow rate is adjusted to 0.5mL / min, the distance between the nozzle and the 12-inch bare silicon wafer is fixed at 60mm, spraying times are 3, and the heating table temperature is set to 50℃.

[0096] Following the steps above, the laser protective liquid is sprayed onto the surface of the 12-inch bare silicon wafer to form a uniform protective film;

[0097] Step 3: Use a picosecond laser with a grooving program of 3W 500mm / s 1pass to create grooves on the wafer surface, and then laser cutting can be performed.

[0098] Regarding performance testing and explanation:

[0099] The performance 1 film thickness TTV test method is as follows:

[0100] After a uniform protective film is formed on the surface of a 12-inch bare silicon wafer, the film thickness at 25 points on the silicon wafer surface is measured using a profilometer, and the range of these 25 data points is calculated. The test data are shown in Table 4.

[0101] The test method for the heat-affected zone of performance 2 is as follows:

[0102] After the laser chip is slotted, the film layer is cleaned with deionized water. The area with morphological difference between the two sides of the dicing track and the wafer surface is observed with a scanning electron microscope (SEM) and its width is recorded. The test results are shown in Table 4.

[0103] The performance 3 etching ratio test method is as follows:

[0104] After laser grooving, the silicon substrate is etched to a depth of approximately 100 μm using dry etching. The film thickness is recorded at this point, and the difference in film thickness before and after etching is calculated. The etching ratio is the ratio of the actual depth of the silicon substrate etched away to the difference in film thickness. The test results are shown in Table 4.

[0105] Table 4 Test Data

[0106] Film thickness TTV (μm) Heat-affected zone (μm) Etching ratio Example 1 0.216 1.35 268 Example 2 0.339 2.33 221 Example 3 0.524 2.66 256 Example 4 0.336 1.77 253 Example 5 0.992 5.03 249 Example 6 0.607 2.13 210 Example 7 0.803 2.03 273 Comparative Example 1 0.223 Film cracking Film cracking Comparative Example 2 0.445 1.92 82 Comparative Example 3 1.206 2.86 156

[0107] Further analysis and explanation of the test results:

[0108] As can be seen from Table 4, the protective liquid of PSS-NVA resin contained in this invention has a TTV of less than 1.0 μm compared with the comparative example, which proves that it has a lower viscosity, forms a more uniform film thickness, and has a smaller heat-affected zone, resulting in a higher etching ratio.

[0109] Compared with Example 1, Comparative Example 1 used sodium polystyrene sulfonate as resin. Although the TTV was low, it cracked after curing. Comparative Example 2 used poly(N-vinylacetamide) as resin. Although the TTV and heat-affected zone were small, the etching ratio was low. Comparative Example 3 used P(NVP-CO-SSS) as resin. The TTV was greater than 1.0 μm, the heat-affected zone was large, the film thickness uniformity was poor, and the etching ratio was significantly lower than that of the Example.

[0110] Further comparison can be made using the accompanying diagrams in the instruction manual:

[0111] Figure 1 The image shows the infrared absorption spectrum of PSS-NVA resin 1. As can be seen from the image, at 1554 cm⁻¹... -1 The presence of a weak C=O vibration peak indicates that the amide group of NVA has been successfully incorporated into the structure of PSS using the preparation method of this invention. Figure 2 The thermogravimetric curve of resin 1 for PSS-NVA is shown in the figure. As can be seen, the thermal decomposition temperature of this resin exceeds 500℃. Figure 3 Using the protective coating solution prepared in Example 1, a protective film was sprayed onto the wafer surface, grooved and etched, and after standing for 72 hours, it was cleaned with deionized water. The image was magnified 50 times and shown in the figure. The film layer was cleaned without residue, and there were no missing etch marks on the wafer surface. Figure 4 The protective coating solution prepared in Example 1 was sprayed onto the surface of a silicon wafer. After grooving and 100μm deep silicon etching, the SEM side view image of the film layer magnified 5000 times showed that the film layer thickness was still above 3μm after etching, indicating a good protective effect on the wafer surface. Figure 5 The protective coating solution prepared in Comparative Example 2 was sprayed onto the surface of a silicon wafer. After grooving and 100 μm deep silicon etching, the SEM side view image of the film layer magnified 5000 times showed that the thickness of the film layer after etching was less than 1 μm, and part of the film layer was penetrated by the etching gas, thus failing to protect the wafer surface.

[0112] The present invention has been described above by way of example with reference to the embodiments and accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A plasma cutting spray protective fluid, characterized in that, The plasma cutting spray protective liquid comprises the following components in parts by weight: 5-20 parts of PSS-NVA resin; Leveling agent 0.1-5 parts; Light absorber 0.1-5 parts; 20-50 parts organic solvent; 40-70 parts ultrapure water; The PSS-NVA resin is copolymerized from sodium p-styrene sulfonate and N-vinylacetamide.

2. The plasma cutting spray protective liquid according to claim 1, characterized in that, The specific preparation method of the PSS-NVA resin is as follows: Step 1: Under nitrogen protection, using ultrapure water as a solvent, stir and mix sodium styrene sulfonate, N-vinyl acetamide and ultrapure water until they are completely dissolved. Then heat to 40-60℃, add initiator and react at a constant temperature for a certain period of time. Step 2: After the reaction is complete, the temperature is lowered to below 25°C, and the copolymer is precipitated with n-butanol as a precipitant. The precipitated copolymer is washed and vacuum dried to obtain powdered PSS-NVA resin.

3. The plasma cutting spray protective liquid according to claim 2, characterized in that: In step 1, the molar ratio of sodium styrene sulfonate to N-vinyl acetamide is 8:1-10:

1.

4. The plasma cutting spray protective liquid according to claim 1, characterized in that: The leveling agent is one or more of the following: silicone, polyester, and acrylate.

5. The plasma cutting spray protective liquid according to claim 1, characterized in that: The light absorber is any one of benzophenones, benzotriazoles, salicylates, triazines, and coumarins that have an absorption peak at 355 nm; or an edible red pigment that has an absorption peak at 532 nm; or any one of azo compounds and anthraquinones that have an absorption peak at 1064 nm.

6. The plasma cutting spray protective liquid according to claim 1, characterized in that: The organic solvent is at least two of methanol, ethanol, propanol, isopropanol, propylene glycol, glycerol, diethylene glycol, propylene glycol methyl ether, propylene glycol ethyl ether, dipropylene glycol ethyl ether, glycerol methyl ether, ethylene glycol ethyl ether, glycerol ethyl ether, acetone, methyl methacrylate, butyl acrylate, and propylene glycol methyl ether acetate.

7. A method for preparing the plasma cutting spray protective liquid according to any one of claims 1-6, characterized in that... Includes the following steps: Step 1: Weigh out the respective amounts of each component; Step 2: Add the organic solvent and leveling agent to the container, mix well, then add ultrapure water. Add PSS-NVA resin evenly while stirring at a feeding rate of 50 parts / min, and stir at room temperature until it is uniform and transparent. Step 3: Add the light absorber while stirring, continue stirring until uniform and transparent, then filter and let stand to defoam, and you will get the plasma cutting spray protective liquid.

8. A method of using the plasma cutting spray protective liquid according to any one of claims 1-6, characterized in that... Includes the following steps: The plasma cutting spray protective liquid is used as a undiluted solution and does not require dilution. The plasma cutting spray protective liquid is atomized into fine particles by an ultrasonic atomization device and coated evenly on the substrate surface in multiple applications to form a protective film.

9. The use of the plasma cutting protective coating liquid according to any one of claims 1-6 in a chip plasma cutting process.

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