Water-based laser cutting wafer protection liquid and preparation method thereof

Abstract

The invention provides a water-based laser cutting wafer protection liquid and a preparation method thereof. The water-based laser cutting wafer protection liquid comprises a water-soluble resin composition, a water-soluble ultraviolet light absorber, a water-soluble organic solvent, a composite corrosion inhibitor, a surface active substance and water, the water-soluble resin composition comprises water-soluble modified phenolic resin, copovidone and a methyl vinyl ether-maleic anhydride copolymer. The protective liquid has good spin coating performance and adhesive force, a uniform and transparent coating protective film is formed on the surface of a wafer in a spin coating mode, the protective film can effectively reduce a heat affected area in the laser cutting process, a cutting opening is straight after film forming, the sintering phenomenon is avoided, and the service life of the cutting opening is prolonged. Condensed silicon steam or other particles and dust generated in the machining process are prevented from being deposited on the surfaces of semiconductor components and chips, and the dust particles are reduced by 99% or above; the wafer wall microcracks are reduced, the wafer corner chipping phenomenon is reduced, and the reliability and the qualified rate of the chip can be greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of chip manufacturing, and in particular to a water-based laser cutting wafer protection liquid and a preparation method thereof. Background Art

[0002] In the chip manufacturing process, wafer slicing refers to the process of cutting the boundary surface of the wafer cutting lanes to separate the side-by-side devices. Faced with the extensive application of low dielectric constant materials or high hardness substrate materials, their mechanical properties have become fragile. In addition, as the spacing between cutting lanes becomes narrower with the increasing degree of semiconductor integration, the wafer cutting process has gradually changed from traditional mechanical blade cutting to a combination of using lasers to drill holes in the wafer and then using mechanical blades. Later, further development introduced the method of using only lasers to cut wafers.

[0003] Laser cutting achieves the purpose of cutting and separation through ablation. Its advantage is that it can greatly reduce cutting damage or control the damage within a small range. However, after absorbing the energy of the laser, the cut material will heat up and vaporize, generating smoke and dust that will fly around, thus causing wafer surface contamination. In addition, laser cutting will densely pile up materials on both sides of the cutting line, causing sintering and blackening on both sides of the cutting path. In order to deal with the problems caused by such laser cutting, there is currently a solution that is to apply a protective film layer on the wafer surface before laser cutting.

[0004] For example, as shown in the Chinese invention patent application with publication number CN110396332A, it discloses a protective film solution for wafer laser cutting and a wafer processing method. Another example is Japanese Patent Publication No. 53-8634, which discloses a laser cutting protective agent containing a water-soluble resin and water. These prior arts propose a cutting processing method in which a water-soluble resin such as polyvinyl alcohol, polyethylene glycol, cellulose, etc. is coated on the top surface of the wafer to form a protective film and then irradiated with a laser.

[0005] However, the above-mentioned prior art also has the following disadvantages when used in practice:

[0006] (1) The protective film formed has insufficient adhesion, which is manifested as the protective film peeling off on both sides of the cutting path, forming an irregular cutting line;

[0007] (2) The protective film has poor thermal stability, undergoes irreversible changes when heated, becomes less water-soluble, and is difficult to clean, resulting in sintering residue problems;

[0008] (3) Insufficient protection for metal materials. During the cutting process, the wafer protection liquid film acts as an electrolyte, causing certain galvanic corrosion to the metal bonding pads and bumps. Summary of the invention

[0009] The object of the present invention is to provide an aqueous laser cutting wafer protective liquid and a preparation method thereof, which can at least solve one of the above problems.

[0010] According to one aspect of the present invention, there is provided an aqueous laser cutting wafer protective liquid, comprising a water-soluble resin composition, a water-soluble ultraviolet absorber, a water-soluble organic solvent, a composite corrosion inhibitor, a surface active substance and water;

[0011] The water-soluble resin composition includes a water-soluble modified phenolic resin, copovidone and a methyl vinyl ether-maleic anhydride copolymer.

[0012] In some embodiments, per kilogram of the aqueous laser cutting wafer protective liquid, it includes:

[0013] The water-soluble resin composition, 150-300 g;

[0014] The water-soluble ultraviolet absorber, 10-30 g;

[0015] The water-soluble organic solvent, 80-150 g;

[0016] The composite corrosion inhibitor, 5-20 g;

[0017] The surface active substance, 0.5-5 g;

[0018] The balance is water.

[0019] In some embodiments, the mass ratio of copovidone, methyl vinyl ether-maleic anhydride copolymer and water-soluble sulfonated modified phenolic resin in the water-soluble resin composition is 3-4:1:0.2-0.5.

[0020] In some embodiments, the water-soluble ultraviolet absorber includes one or more of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, phenyl dibenzimidazole tetrasulfonate disodium, 2-phenylbenzimidazole-5-sulfonic acid, 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfonic acid benzophenone. Thus, the water-soluble ultraviolet absorber has a high UV laser absorption efficiency, effectively reducing the thermally affected area on the wafer during laser cutting, thereby effectively reducing the deposition of silicon vapor or other particles and dust on the surface of semiconductor components and chips due to overheating.

[0021] In some embodiments, the water-soluble organic solvent is one or more of methanol, ethanol, isopropanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, N-methylpyrrolidone, N,N-dimethylformamide. Thus, the water-soluble organic solvents are all miscible with water and have an appropriate evaporation rate, which can not only reduce the viscosity index of the cutting protective liquid, but also accelerate the evaporation of water during the spin coating process, promoting the hardening formation of the protective film, thereby improving the spin coating property and the film thickness of the protective film.

[0022] In some embodiments, the composite corrosion inhibitor is a soapy salt formed by the neutralization reaction of one or more organic carboxylic acids and one or more organic amines. Thus, the composite corrosion inhibitor can effectively avoid the galvanic corrosion phenomenon of metal bonding pads and bumps formed on the wafer.

[0023] In some embodiments, the organic carboxylic acids include acetic acid, propionic acid, isooctanoic acid, heptanoic acid, octyldecanoic acid, benzoic acid, and salicylic acid.

[0024] In some embodiments, the organic amines include diethanolamine, triethanolamine, N,N-dimethylethanolamine, diethylene glycol amine, diisopropanolamine, diethylenetriamine, triethylenetetramine, benzotriazole, and hydroxybenzotriazole.

[0025] In some embodiments, the mass ratio of the organic carboxylic acid to the organic amine is 1:2 to 5.

[0026] In some embodiments, the surface active substance is one or more of water-soluble polyether-modified silicone, water-soluble nonionic polyoxyethylene ether, and water-soluble ethylene oxide-propylene oxide block copolymer. Thus, the surface active substance has a wetting and penetrating effect and can assist in improving the coating property and leveling property of the protective liquid.

[0027] According to one aspect of the present invention, there is also provided a method for preparing a water-based laser cutting wafer protective liquid, which is characterized by at least including the following steps:

[0028] S1. Prepare the composite corrosion inhibitor;

[0029] S2. Add the water-soluble resin composition, water-soluble ultraviolet absorber, water-soluble organic solvent, the composite corrosion inhibitor prepared in step S1, and the surface active substance into water, and stir and dissolve at a stirring rate of 400 - 600 rpm at room temperature for 60 minutes to obtain the water-based laser cutting wafer protective liquid.

[0030] The beneficial effects of the present invention:

[0031] 1. The present invention provides an aqueous laser cutting wafer protective liquid, which includes a water-soluble resin composition formed by combining three components: water-soluble sulfonated modified phenolic resin, copovidone, and a mixture of methyl vinyl ether-maleic anhydride copolymer. This water-soluble resin composition is the matrix material of the protective film, having excellent solubility in water. After coating and drying, it can form a uniform and defect-free thin film coating. The protective film coating formed on the wafer has heat resistance stability and adhesion. After cutting, there is no glue peeling, and it still maintains excellent water solubility. There is no sintering residue after water washing; in the chemical structures of the water-soluble sulfonated modified phenolic resin, copovidone, and methyl vinyl ether-maleic anhydride copolymer, there are a large number of carboxyl (carbonyl) and sulfonic acid functional groups with relatively large polarity. Therefore, it not only has excellent water solubility and film-forming property by coating, but also the carboxyl (carbonyl) and sulfonic acid functional groups have a strong adsorption and bonding ability to the metal and substrate materials on the wafer surface, showing stronger adhesion macroscopically. Thus, it can well avoid glue peeling on both sides of the cutting line, and thus well avoid the phenomenon of crater defects formed during cutting.

[0032] 2. The water-soluble ultraviolet absorber has a high UV laser absorption efficiency, which can effectively reduce the heat-affected area on the wafer during the laser cutting process, so that the protective film is not easily heated and vaporized or formed into debris particles or sintered and deteriorated after absorbing laser energy, and deposited on the surface of semiconductor components and chips and both sides of the cutting channels. Therefore, it can effectively improve the reliability and qualification rate of the chips.

[0033] 3. The water-soluble organic solvents can be miscible with water and have an appropriate evaporation rate. They can not only reduce the viscosity index of the cutting protective liquid, but also accelerate the evaporation of water during the spin-coating process, promoting the hardening formation of the protective film, thereby improving the spin-coating property and the film thickness of the protective film.

[0034] 4. The composite corrosion inhibitor can effectively protect the metal bonding pads and bumps, and thus prevent the occurrence of corrosion (such as galvanic corrosion) behavior.

[0035] 5. The surface active substance has a wetting and penetrating effect, which can assist in improving the coating property and leveling property of the protective liquid. Detailed Embodiments

[0036] The present invention will be further described in detail below.

[0037] The aqueous laser cutting wafer protective liquid of the present invention includes a water-soluble resin composition, a water-soluble ultraviolet absorber, a water-soluble organic solvent, a composite corrosion inhibitor, a surface active substance, and water.

[0038] The water-soluble resin composition of the present invention is a combination of three components: water-soluble sulfonated modified phenolic resin, copovidone, and methyl vinyl ether-maleic anhydride copolymer.

[0039] Preferably, per kilogram of the water-based laser cutting wafer protective liquid includes:

[0040] A water-soluble resin composition, 150 - 300 g;

[0041] A water-soluble ultraviolet absorber, 10 - 30 g;

[0042] A water-soluble organic solvent, 80 - 150 g;

[0043] A composite corrosion inhibitor, 5 - 20 g;

[0044] A surface active substance, 0.5 - 5 g;

[0045] The balance is water.

[0046] The water-soluble resin composition is the matrix material of the protective film. Firstly, it is required to have excellent solubility in water and be able to form a uniform and defect-free thin film coating after coating and drying; secondly, the protective film coating formed on the wafer is required to have heat resistance stability and adhesion, no debonding after cutting, still maintain excellent water solubility, and no sintering residue after water washing.

[0047] The water-soluble resin composition of the present invention is a combination of three components: water-soluble sulfonated modified phenolic resin, copovidone, and methyl vinyl ether - maleic anhydride copolymer. The chemical structures of water-soluble sulfonated modified phenolic resin, copovidone, and methyl vinyl ether - maleic anhydride copolymer contain a large number of carboxyl (carbonyl) and sulfonic acid functional groups with relatively large polarity. Therefore, it not only has excellent water solubility and film-forming property by coating, but also the carboxyl (carbonyl) and sulfonic acid functional groups have a strong adsorption and bonding ability to the metal and substrate materials on the wafer surface, showing stronger adhesion macroscopically. Thus, it can well avoid debonding on both sides of the cutting line and well avoid the phenomenon of crater defects formed during cutting.

[0048] Preferably, the mass ratio of the three components of water-soluble sulfonated modified phenolic resin, copovidone, and methyl vinyl ether - maleic anhydride copolymer is 3 - 4:1:0.2 - 0.5.

[0049] Preferably, copovidone is selected from the commercial products of American PVP / VA S - 630 or American ISP Ashland PVP / VA W - 735. Among them, the full spelling of PVP is Polyvinyl pyrrolidone, and the Chinese name is polyvinylpyrrolidone. The full spelling of VA is Vinyl Acetate, and the Chinese name is vinyl acetate.

[0050] Preferably, the methyl vinyl ether - maleic anhydride copolymer is selected from the methyl vinyl ether - maleic anhydride copolymer commercial products produced by Wuhan Smart Bio-Tech Co., Ltd.

[0051] Preferably, the water-soluble sulfonated modified phenolic resin is the water-soluble sulfonated modified phenolic resin of model K-11 produced by Hebei Jintai Chemical Co., Ltd.

[0052] Preferably, the water-soluble ultraviolet absorber is one or more of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (CAS Registry Number: 4065-45-6), diphenyl dibenzimidazole tetrasulfonate disodium (CAS Registry Number: 180898-37-7), 2-phenylbenzimidazole-5-sulfonic acid (CAS Registry Number: 27503-81-7), 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfonate benzophenone (CAS Registry Number: 76656-36-5).

[0053] The water-soluble ultraviolet absorber is selected with its designed UV absorption peak in the range of 330-370 nm. Generally, the laser light wavelength used in laser cutting is within this wavelength range, so it shows higher UV laser absorption efficiency, effectively reducing the thermally affected area on the wafer during the laser cutting process, thus effectively reducing the deposition of silicon vapor or other particles and dust on the surface of semiconductor components and chips due to overheating.

[0054] Preferably, the water-soluble organic solvent is methanol, ethanol, isopropanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, N-methylpyrrolidone, N,N-dimethylformamide.

[0055] The above water-soluble organic solvents can be miscible with water and have appropriate evaporation rates. They can not only reduce the viscosity index of the cutting protective liquid, but also accelerate the evaporation of water during the spin-coating process, promoting the hardening of the protective film, thereby improving the spin-coating coatability and the film thickness of the protective film. The usage amount of this water-soluble organic solvent also needs to be considered. Too high or too low will affect the uniformity of the overall thickness of the spin-coated film. If the usage amount is insufficient, the viscosity index of the protective liquid is too high, resulting in very poor spin-coatability of the protective liquid and a very uneven protective film after spin-coating on the substrate; if the usage amount of the organic solvent is too much, the protective film formed during the spin-coating process will harden quickly, and the thickness of the protective film shows an uneven gradient change in the expansion direction.

[0056] Preferably, the composite corrosion inhibitor is a soap salt formed by the neutralization reaction of one or more organic carboxylic acids and one or more organic amines. The composite corrosion inhibitor can effectively avoid the galvanic corrosion phenomenon of the metal bonding pads and bumps formed on the wafer.

[0057] In the above neutralization reaction, the mass ratio of the organic carboxylic acid to the organic amine in the feed is 1:2-5.

[0058] As a further preference, the organic carboxylic acids include acetic acid, propionic acid, isooctanoic acid, heptanoic acid, octanoic acid, benzoic acid, salicylic acid.

[0059] As a further preference, the organic amine includes diethanolamine, triethanolamine, N, N-dimethylethanolamine, diethylene glycol amine, diisopropanolamine, diethylenetriamine, triethylenetetramine, benzotriazole, and hydroxybenzotriazole.

[0060] As a preference, the surfactant is water-soluble polyether-modified silicone, water-soluble nonionic polyoxyethylene ether, and water-soluble ethylene oxide-propylene oxide block copolymer. The surfactant functions as wetting and penetration to assist in improving the coating property and leveling property of the protective liquid.

[0061] As a preference, the water is deionized water.

[0062] The components without indicating the manufacturer and model above are all commercially available products.

[0063] The present invention also provides a preparation method of the above water-based laser cutting wafer protective liquid, including the following steps:

[0064] S1. React the organic carboxylic acid and the organic amine at 50-70 °C for heat preservation for 30-40 minutes to obtain a composite corrosion inhibitor;

[0065] S2. Add the water-soluble resin composition, water-soluble ultraviolet absorber, water-soluble organic solvent, composite corrosion inhibitor, and surfactant to water, and stir and dissolve at a stirring rate of 400-600 rpm at room temperature for 60 minutes to obtain a water-based laser cutting wafer protective liquid;

[0066] S3. Filter the water-based laser cutting wafer obtained in step S2 using a microfiltration membrane.

[0067] In step S3, the microfiltration membrane can adopt a microfiltration membrane with a pore size of about 0.5 μm to filter out insoluble impurity particles to ensure the flatness and uniformity after film formation of the formed protective film layer.

[0068] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. The experimental methods without specifying specific conditions in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0069] Example 1

[0070] The specific components and contents in 1 kg of the water-based laser cutting wafer protective liquid in this example are shown in Table 1 below.

[0071] Table 1: Formulation table of the water-based laser cutting wafer protective liquid in Example 1

[0072] Component Dosage Copovidone (PVP / VA S-630) 208g Methyl vinyl ether-maleic anhydride copolymer 52g Water-soluble sulfonated modified phenolic resin 26g Isopropanol 105g 2-Hydroxy-4-methoxybenzophenone-5-sulfonic acid 25g N,N-Dimethylethanolamine 8g Benzotriazole 2g Acetic acid 3g Water-soluble silicone-modified polyether 1.5g Deionized water Balance

[0073] According to the formulation table in Table 1 above, the above water-based laser cutting wafer protective liquid is prepared by the following preparation method, which specifically includes the following steps:

[0074] S1. Add 3 grams of acetic acid, 2 grams of benzotriazole, and 8 grams of N,N-dimethylethanolamine, and carry out a heat preservation reaction at 50 - 70 °C for 30 - 40 minutes to obtain a composite corrosion inhibitor;

[0075] S2. Add 208 grams of copolyvidone (PVP / VA S-630), 52 grams of methyl vinyl ether-maleic anhydride copolymer, 26 grams of water-soluble sulfonated modified phenolic resin, 25 grams of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 105 grams of isopropanol, the composite corrosion inhibitor prepared in step S1, and 1.5 grams of water-soluble organosilicon-modified polyether into deionized water, stir and dissolve at a stirring rate of 400 - 600 rpm at room temperature for 60 minutes, and use a microfiltration membrane with a pore size of about 0.5 μm to filter out insoluble impurity particles to obtain the water-based laser cutting wafer protective liquid.

[0076] Example 2

[0077] The specific components and contents in 1 kg of the water-based laser cutting wafer protective liquid in this example are shown in Table 2 below.

[0078] Table 2: Formulation table of the water-based laser cutting wafer protective liquid in Example 2

[0079] Component Dosage Copovidone (PVP / VAW-735) 208g Methyl vinyl ether-maleic anhydride copolymer 52g Water-soluble sulfonated modified phenolic resin 20g Isopropanol 105g 2-Hydroxy-4-methoxybenzophenone-5-sulfonic acid 25g N,N-Dimethylethanolamine 8g Benzotriazole 2g Benzoic acid 3g Water-soluble silicone-modified polyether 1.5g Deionized water Balance

[0080] According to the formulation table in Table 2 above, the above water-based laser cutting wafer protective liquid is prepared by the following preparation method, which specifically includes the following steps:

[0081] S1. Add 3 grams of benzoic acid, 2 grams of benzotriazole, and 8 grams of N,N-dimethylethanolamine, and carry out a heat preservation reaction at 50 - 70 °C for 30 - 40 minutes to obtain a composite corrosion inhibitor;

[0082] S2. Add 208 grams of copolyvidone (PVP / VA W-735), 52 grams of methyl vinyl ether-maleic anhydride copolymer, 20 grams of water-soluble sulfonated modified phenolic resin, 25 grams of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 105 grams of isopropanol, the composite corrosion inhibitor prepared in step S1, and 1.5 grams of water-soluble organosilicon-modified polyether into deionized water, stir and dissolve at a stirring rate of 400 - 600 rpm at room temperature for 60 minutes, and use a microfiltration membrane with a pore size of about 0.5 μm to filter out insoluble impurity particles to obtain the water-based laser cutting wafer protective liquid.

[0083] Example 3

[0084] The specific components and contents in 1 kg of the water-based laser cutting wafer protective liquid of this embodiment are shown in Table 3 below.

[0085] Table 3: Formulation table of the water-based laser cutting wafer protective liquid of Example 3

[0086] Component Dosage Copovidone (PVP / VA S-630) 208g Methyl vinyl ether-maleic anhydride copolymer 52g Water-soluble sulfonated modified phenolic resin 11g Isopropanol 105g Propylene glycol methyl ether 35g 2,2′-Dihydroxy-4,4′-dimethoxy-5,5′-disulfonate benzophenone 15g N,N-Dimethylethanolamine 8g Hydroxybenzimidazole 2g Benzoic acid 3g Water-soluble ethylene oxide-propylene oxide block copolymer 1.5g Water Balance

[0087] According to the formulation table in Table 3 above, the above water-based laser cutting wafer protective liquid is prepared by the following preparation method, which specifically includes the following steps:

[0088] S1. Add 3 g of benzoic acid, 2 g of hydroxybenzimidazole, and 8 g of N,N-dimethylethanolamine, and carry out a heat preservation reaction at 50-70 °C for 30-40 minutes to obtain a composite corrosion inhibitor;

[0089] S2. Add 208 g of copolyvinylpyrrolidone (PVP / VA S-630), 52 g of methyl vinyl ether-maleic anhydride copolymer, 11 g of water-soluble sulfonated modified phenolic resin, 15 g of 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfonate benzophenone, 105 g of isopropanol, 35 g of propylene glycol methyl ether, the composite corrosion inhibitor prepared in step S1, and 1.5 g of water-soluble ethylene oxide-propylene oxide block copolymer into deionized water, stir and dissolve at a stirring rate of 400-600 rpm at room temperature for 60 minutes, and use a microfiltration membrane with a pore size of about 0.5 μm to filter out insoluble impurity particles to obtain the water-based laser cutting wafer protective liquid.

[0090] Example 4

[0091] The specific components and contents in 1 kg of the water-based laser cutting wafer protective liquid of this embodiment are shown in Table 4 below.

[0092] Table 4: Formulation table of the water-based laser cutting wafer protective liquid of Example 4

[0093] Component Dosage Copovidone (PVP / VA S-630) 103g Methyl vinyl ether-maleic anhydride copolymer 36g Water-soluble sulfonated modified phenolic resin 11g Isopropanol 105g 2-Hydroxy-4-methoxybenzophenone-5-sulfonic acid 15g 2,2′-Dihydroxy-4,4′-dimethoxy-5,5′-disulfonate benzophenone 15g N,N-Dimethylethanolamine 8g Hydroxybenzimidazole 2g Isooctanoic acid 3g Water-soluble nonionic polyoxyethylene ether 1.5g Water Balance

[0094] According to the formulation table in Table 4 above, the above water-based laser cutting wafer protective liquid is prepared by the following preparation method, which specifically includes the following steps:

[0095] S1. Add 3 g of isooctanoic acid, 2 g of hydroxybenzimidazole, and 8 g of N,N-dimethylethanolamine, and carry out a heat preservation reaction at 50-70 °C for 30-40 minutes to obtain a composite corrosion inhibitor;

[0096] S2. Add 103 g of copovidone (PVP / VA S-630), 36 g of methyl vinyl ether-maleic anhydride copolymer, 11 g of water-soluble sulfonated modified phenolic resin, 15 g of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 15 g of 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfonate benzophenone, 105 g of isopropyl alcohol, the composite corrosion inhibitor obtained in step S1, and 1.5 g of water-soluble non-ionic polyoxyethylene ether into deionized water, stir and dissolve at a stirring rate of 400 - 600 rpm at room temperature for 60 minutes, and use a microfiltration membrane with a pore size of about 0.5 μm to filter out insoluble impurity particles to obtain a water-based laser cutting wafer protective liquid.

[0097] Example 5

[0098] Perform spin coating property test, cutting property test and cleaning property test on the water-based laser cutting wafer protective liquids prepared in the above Examples 1 - 4 respectively, and the performance test results of the water-based laser cutting wafer protective liquids of Examples 1 - 4 are shown in Table 5 below for reference.

[0099] Spin coating property test: Through spin coating operation, place an appropriate amount of protective liquid in the center of the bare silicon wafer, rotate slowly first, and then rotate at high speed until the protective liquid volatilizes, dries and hardens, and use an optical reflection film thickness gauge to measure the film thickness in different areas of the wafer to examine the uniformity and consistency of the protective film.

[0100] Cutting property test: Use a nanosecond pulsed laser for cutting, with the parameters selected as light wavelength 355 nm, frequency 40 KHz, scribing speed 200 mm / s, cutting width 50 μm, and power 2.0 W, and observe the physical properties of the cutting edge.

[0101] Cleaning property test: It refers to cleaning the cut workpiece with water at a certain pressure and detecting whether there is a problem of sintering residue.

[0102] Table 5: Performance test table of the water-based laser cutting wafer protective liquids of Examples 1 - 4

[0103]

[0104] Judging from the test results in Table 5 above, after laser cutting, the protective films formed by the wafer laser cutting protective liquids prepared in Examples 1 - 4 on the substrate have straight cutting edges, no serrations, and no sintered black spot residues after cutting and cleaning.

[0105] The above test structure shows that the water-based laser cutting wafer protective liquid of the present invention has good spin-coatability and adhesion. Through the spin-coating method, a uniform and transparent coating protective film is formed on the wafer surface. This protective film has excellent UV absorption efficiency, can effectively reduce the thermally affected area during laser cutting. After film formation, the cutting edge is straight, without sintering phenomenon, and can prevent the deposition of condensed silicon vapor or other particles and dust generated during the processing on the surface of semiconductor components and chips, with the dust particles reduced by more than 99%. It reduces microcracks on the wafer wall and wafer chipping phenomenon. At the same time, the protective film has excellent water solubility, and can be cleaned with pure water without residue, greatly improving the reliability and qualification rate of the chips.

[0106] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A water-based laser cutting wafer protection liquid, characterized in that, It includes a water-soluble resin composition, a water-soluble ultraviolet absorber, a water-soluble organic solvent, a composite corrosion inhibitor, a surfactant, and water; The water-soluble resin composition includes a water-soluble modified phenolic resin, copovidone, and a methyl vinyl ether-maleic anhydride copolymer; Per kilogram of the water-based laser cutting wafer protective liquid, it includes: Water-soluble resin composition, 150 - 300 g; Water-soluble ultraviolet absorber, 10 - 30 g; Water-soluble organic solvent, 80 - 150 g; Composite corrosion inhibitor, 5 - 20 g; Surfactant, 0.5 - 5 g; The balance is water.

2. The water-based laser cutting wafer protection liquid according to claim 1, wherein The mass ratio of copovidone, methyl vinyl ether-maleic anhydride copolymer, and water-soluble sulfonated modified phenolic resin in the water-soluble resin composition is 3 - 4:1:0.2 - 0.

5.

3. The water-based laser cutting wafer protection liquid according to claim 1, characterized in that, The water-soluble ultraviolet absorber includes one or more of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, phenyl dibenzimidazole tetrasulfonate disodium, 2-phenylbenzimidazole-5-sulfonic acid, 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfonic acid benzophenone.

4. The water-based laser cutting wafer protection liquid according to claim 1, wherein, The water-soluble organic solvent is one or more of methanol, ethanol, isopropanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, N-methylpyrrolidone, N,N-dimethylformamide.

5. The water-based laser cutting wafer protective liquid according to claim 1, wherein The composite corrosion inhibitor is a soap salt substance formed by the neutralization reaction of one or more organic carboxylic acids and one or more organic amines.

6. The water-based laser cutting wafer protective liquid according to claim 5, characterized in that, The organic carboxylic acids include acetic acid, propionic acid, isooctanoic acid, heptanoic acid, octanoic acid, benzoic acid, salicylic acid.

7. The water-based laser cutting wafer protection liquid according to claim 5, characterized in that, The organic amines include diethanolamine, triethanolamine, N,N-dimethylethanolamine, diethylene glycol amine, diisopropanolamine, diethylenetriamine, triethylenetetramine, benzotriazole, hydroxybenzotriazole.

8. The water-based laser cutting wafer protection liquid according to claim 5, characterized in that, The mass ratio of the organic carboxylic acid to the organic amine is 1:2 - 5.

9. The water-based laser cutting wafer protection liquid according to claim 1, characterized in that, The surfactant is one or more of water-soluble polyether-modified silicone, water-soluble non-ionic polyoxyethylene ether, water-soluble ethylene oxide-propylene oxide block copolymer.

10. A preparation method of the water-based laser cutting wafer protective liquid according to any one of claims 1 to 9, characterized in that, It includes the following steps: S1. Prepare the composite corrosion inhibitor; S2. Add the water-soluble resin composition, water-soluble ultraviolet absorber, water-soluble organic solvent, the composite corrosion inhibitor prepared in step S1, and the surfactant into water, and stir and dissolve at a stirring rate of 400 - 600 rpm at room temperature for 60 minutes to obtain the water-based laser cutting wafer protective liquid.

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