Wafer cutting protection liquid and preparation method thereof

Abstract

The invention relates to a wafer cutting protection liquid and a preparation method thereof. The wafer cutting protection liquid comprises the following raw materials: modified water-soluble resin, an organic solvent, a wetting agent, a pH regulator, an ultraviolet light absorber and water. The modified water-soluble resin is prepared by the following steps: carrying out free radical polymerization reaction on vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and 3, 3-dimethyl acrylate to obtain a copolymer, and then carrying out alcoholysis on the copolymer to obtain modified polyvinyl alcohol. The invention has the following beneficial effects: by using the modified water-soluble resin composed of the vinyl acetate, the ethyl-3-(1-pyrrolidinyl) ethyl acrylate and the 3, 3-dimethyl acrylate copolymer, a protective film can be rapidly formed on the surface of a wafer; and meanwhile, the protective film layer formed by the wafer cutting protective liquid can be completely removed by using pure water. According to the wafer cutting protection liquid disclosed by the invention, a cutting line can be straight without edge breakage during wafer laser cutting, and sintering can be effectively avoided.

Description

Technical Field

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

[0002] Wafer dicing is an indispensable process in the chip manufacturing process and is a post-process of wafer manufacturing. It prepares for subsequent processes by dividing the whole wafer into single chips.

[0003] At present, the existing mainstream cutting (also known as cutting and separation) process is performed by cutting tools along the cutting path of the wafer. However, due to the narrowing of the width of the wafer cutting path and the high-precision semiconductor cutting device, some thermal effect problems will be caused during use, such as the cutting path cracking and breaking due to heat, which will cause a high defective rate of the processed chips. In addition, although the current wafer cutting process has evolved from the original simple blade cutting to laser cutting, when the laser is irradiated along the cutting path of the wafer for cutting, the heat energy generated is easily absorbed by the wafer, resulting in the accumulation of heat energy on the wafer, which is easy to cause the wafer to break and damage during the laser processing process. In addition, the heat energy is easy to cause silicon to melt or thermally decompose, generating silicon vapor that condenses and deposits on the wafer, causing debris to be generated around the edge of the wafer, thereby affecting the reliability of the product.

[0004] Therefore, in view of the shortcomings of the prior art, it is necessary to provide a wafer cutting protection liquid and a preparation method thereof to solve the shortcomings of the prior art. Summary of the invention

[0005] The first purpose of the present invention is to avoid the shortcomings of the prior art and provide a wafer cutting protection liquid, which can avoid carbonized residues on the chip surface.

[0006] The above-mentioned purpose of the present invention is achieved by the following technical measures:

[0007] Provided is a wafer cutting protection liquid, the raw materials of which contain modified water-soluble resin, organic solvent, wetting agent, pH regulator, ultraviolet absorber and water.

[0008] The modified water-soluble resin is prepared by free radical polymerization of vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and 3,3-methyl dimethacrylate to obtain a copolymer, and then alcoholysis of the copolymer is performed to obtain the modified polyvinyl alcohol.

[0009] In parts by weight,

[0010] Modified water-soluble resin: 30 to 50 parts;

[0011] Organic solvent: 10 to 20 parts;

[0012] Wetting agent: 1 to 3 parts;

[0013] pH adjuster: 0.5 to 2 parts;

[0014] Ultraviolet absorber: 1 to 5 parts;

[0015] The balance is water, and the total amount of all components is calculated as 100 parts.

[0016] Further, in parts by weight,

[0017] Modified water-soluble resin: 42.5 parts;

[0018] Organic solvent: 15 parts;

[0019] Wetting agent: 2.3 parts;

[0020] pH regulator: 1.2 parts;

[0021] Ultraviolet light absorber: 3.5 parts;

[0022] The balance is water, and the total amount of all components is calculated as 100 parts.

[0023] In the modified water-soluble resin, in parts by weight,

[0024] Vinyl acetate: 30 to 50 parts;

[0025] Ethyl 3-(1-pyrrolidinyl)acrylate: 5 to 10 parts;

[0026] 3,3-dimethacrylate methyl ester: 3 to 8 parts;

[0027] Methanol I: 50 to 80 parts;

[0028] Methanol II: 20 to 50 parts;

[0029] Methanol III: 100 to 200 parts;

[0030] NaOH methanol solution: 100 to 150 parts;

[0031] Initiator: 0.1 to 1 part.

[0032] Furthermore, in the modified water-soluble resin, in parts by weight,

[0033] Vinyl acetate: 40 parts;

[0034] Ethyl-3-(1-pyrrolidinyl)acrylate: 6.7 parts;

[0035] 3,3-dimethacrylate methyl ester: 4.6 parts;

[0036] Methanol I: 60 parts;

[0037] Methanol II: 30 parts;

[0038] Methanol III: 150 parts;

[0039] NaOH methanol solution: 135 parts;

[0040] Initiator: 0.8 parts.

[0041] Preferably, the modified water-soluble resin is prepared by the following steps:

[0042] S1, mixing vinyl acetate and ethyl-3-(1-pyrrolidinyl)acrylate to obtain a mixed solution;

[0043] S2, adding an initiator and methyl 3,3-dimethacrylate into methanol I to obtain solution I;

[0044] S3, adding solution I to the mixed solution obtained in S1 at a constant rate, and entering S4;

[0045] S4, continue the reaction to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and methyl 3,3-dimethacrylate, distill under reduced pressure, and enter S5;

[0046] S5. Dissolve the copolymer obtained in S4 in methanol III, add NaOH methanol solution to perform alcoholysis to obtain a modified water-soluble resin.

[0047] Preferably, the modified water-soluble resin is prepared by the following steps:

[0048] S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 50° C. to 60° C., and obtain a mixed solution;

[0049] S2, adding vinyl acetate to methanol I, controlling the temperature at 0°C to 5°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 0°C to 5°C, to obtain solution II;

[0050] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 50°C to 60°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both of which are 30min to 60min, and then entering S4;

[0051] S4, continue the reaction for 5h to 8h to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl)acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 30°C to 60°C and a pressure of 1.5 kPa to 3.0 kPa for 2h to 3h, and enter S5;

[0052] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 10% g / L-20% g / L NaOH methanol solution, and perform alcoholysis at a temperature of 40°C to 60°C for 2h to 3h to obtain a modified water-soluble resin.

[0053] Preferably, the modified water-soluble resin is prepared by the following steps:

[0054] S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 55° C., and obtain a mixed solution;

[0055] S2, adding vinyl acetate to methanol I, controlling the temperature at 2°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 2°C, to obtain solution II;

[0056] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 55°C to 57°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both for 45 minutes, and then entering S4;

[0057] S4, continue the reaction for 6 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 42° C. and a pressure of 3.0 kPa for 2.5 hours, and enter S5;

[0058] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 15% g / L NaOH methanol solution, and perform alcoholysis at 52° C. for 2.5 h to obtain a modified water-soluble resin.

[0059] Preferably, the initiator is azobisisobutyronitrile, dimethyl azobisisobutyrate or di-tert-butyl peroxide.

[0060] Preferably, the wetting agent is an acrylic leveling agent;

[0061] Preferably, the pH adjuster is N,N-dimethylethanolamine;

[0062] Preferably, the organic solvent is ethylene glycol methyl ether, propylene glycol methyl ether or dioxane;

[0063] Preferably, the ultraviolet absorber is o-hydroxybenzophenone, benzotriazole or salicylate.

[0064] The second purpose of the present invention is to avoid the shortcomings of the prior art and provide a method for preparing a wafer cutting protection liquid. The wafer cutting protection liquid prepared by the method can avoid carbonized residue on the chip surface.

[0065] The above-mentioned purpose of the present invention is achieved by the following technical measures:

[0066] A method for preparing the wafer cutting protection liquid as described above is provided, which is prepared by the following steps:

[0067] A1. Add modified water-soluble resin, organic solvent, wetting agent, pH adjuster, ultraviolet absorber and water into a mixer;

[0068] A2. Mix for 2 h to 3 h at a stirring rate of 500 r / min to 1000 r / min to obtain the wafer cutting protection liquid.

[0069] The present invention relates to a wafer cutting protection liquid and a preparation method thereof, wherein the wafer cutting protection raw material contains a modified water-soluble resin, an organic solvent, a wetting agent, a pH adjusting agent, an ultraviolet absorber and water. The modified water-soluble resin is obtained by free radical polymerization of vinyl acetate, ethyl-3-(1-pyrrolidinyl)ethyl acrylate and methyl 3,3-dimethacrylate to obtain a copolymer, and then the copolymer is alcoholyzed to obtain a modified polyvinyl alcohol. The beneficial effects of the present invention are as follows: the present invention can quickly form a protective film on the surface of a wafer by using a modified water-soluble resin composed of a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl)ethyl acrylate and methyl 3,3-dimethacrylate, and at the same time, pure water can be used to completely remove the protective film layer formed by the wafer cutting protection liquid. The wafer cutting protection liquid of the present invention can make the cutting line straight without edge collapse during wafer laser cutting, and can also effectively avoid sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The present invention is further described with reference to the accompanying drawings, but the contents in the accompanying drawings do not constitute any limitation to the present invention.

[0071] Figure 1 This is an enlarged view of the cutting line after the wafer is cut using the wafer cutting protection liquid of Example 1.

[0072] Figure 2 This is an enlarged view of the cutting line after cutting using the wafer cutting protection liquid of Example 2.

[0073] Figure 3 This is an enlarged view of the cutting line after cutting using the wafer cutting protection liquid of Example 3.

[0074] Figure 4 This is an enlarged view of the cutting line after cutting using the wafer cutting protection liquid of Comparative Example 5. DETAILED DESCRIPTION

[0075] The technical solution of the present invention is further described in conjunction with the following examples. Unless otherwise specified, the raw materials used in the following examples are all commercially available products.

[0076] Example 1

[0077] A wafer cutting protection liquid comprises raw materials including modified water-soluble resin, organic solvent, wetting agent, pH regulator, ultraviolet absorber and water; wherein the modified water-soluble resin has a molecular weight of 3000-4000.

[0078] The modified water-soluble resin is prepared by free radical polymerization of vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and 3,3-methyl dimethacrylate to obtain a copolymer, and then alcoholysis of the copolymer is performed to obtain the modified polyvinyl alcohol.

[0079] Wherein, the weight parts of each component are shown in Table 1:

[0080] Table 1. Weight parts of each component of Example 1

[0081]

[0082]

[0083] Wherein, the modified water-soluble resin is prepared by the following steps:

[0084] S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 60° C., and obtain a mixed solution;

[0085] S2, adding vinyl acetate to methanol I, controlling the temperature at 0°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 0°C, to obtain solution II;

[0086] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 50°C to 60°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both for 60 minutes, and then entering S4;

[0087] S4, continue the reaction for 5 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 60° C. and a pressure of 3.0 kPa for 23 hours, and enter S5;

[0088] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 10% g / L NaOH methanol solution, and perform alcoholysis at 60° C. for 3 h to obtain a modified water-soluble resin.

[0089] The method for preparing the wafer cutting protection liquid comprises the following steps:

[0090] A1. Add modified water-soluble resin, organic solvent, wetting agent, pH adjuster, ultraviolet absorber and water into a mixer;

[0091] A2. Mix for 2 h at a stirring rate of 500 r / min to obtain the wafer cutting protection liquid.

[0092] Example 2

[0093] A wafer cutting protection liquid comprises raw materials including modified water-soluble resin, organic solvent, wetting agent, pH regulator, ultraviolet absorber and water; wherein the modified water-soluble resin has a molecular weight of 3000-4000.

[0094] The modified water-soluble resin is prepared by free radical polymerization of vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and 3,3-methyl dimethacrylate to obtain a copolymer, and then alcoholysis of the copolymer is performed to obtain the modified polyvinyl alcohol.

[0095] Wherein, the weight parts of each component are shown in Table 2:

[0096] Table 2. Weight parts of each component of Example 2

[0097]

[0098]

[0099] Wherein, the modified water-soluble resin is prepared by the following steps:

[0100] S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 50° C., and obtain a mixed solution;

[0101] S2, adding vinyl acetate to methanol I, controlling the temperature at 5°C, to obtain solution I; adding initiator to methanol II, controlling the temperature at 5°C, to obtain solution II;

[0102] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 53°C to 55°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both for 30 minutes, and then entering S4;

[0103] S4, continue the reaction for 8 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 30° C. and a pressure of 1.5 kPa for 3 hours, and enter S5;

[0104] S5. Dissolve the copolymer obtained in S4 in methanol II, add a 20% g / L NaOH methanol solution, and perform alcoholysis at 40°C for 2 hours to obtain a modified water-soluble resin.

[0105] The method for preparing the wafer cutting protection liquid comprises the following steps:

[0106] A1. Add modified water-soluble resin, organic solvent, wetting agent, pH adjuster, ultraviolet absorber and water into a mixer;

[0107] A2. Mix for 2 h at a stirring rate of 1000 r / min to obtain the wafer cutting protection liquid.

[0108] Example 3

[0109] A wafer cutting protection liquid comprises raw materials including modified water-soluble resin, organic solvent, wetting agent, pH regulator, ultraviolet absorber and water; wherein the modified water-soluble resin has a molecular weight of 3000-4000.

[0110] The modified water-soluble resin is prepared by free radical polymerization of vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and 3,3-methyl dimethacrylate to obtain a copolymer, and then alcoholysis of the copolymer is performed to obtain the modified polyvinyl alcohol.

[0111] Wherein, the weight parts of each component are shown in Table 3:

[0112] Table 3. Weight parts of each component of Example 3

[0113]

[0114] Wherein, the modified water-soluble resin is prepared by the following steps:

[0115] S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 55° C., and obtain a mixed solution;

[0116] S2, adding vinyl acetate to methanol I, controlling the temperature at 2°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 2°C, to obtain solution II;

[0117] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 55°C to 57°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both for 45 minutes, and then entering S4;

[0118] S4, continue the reaction for 6 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 42° C. and a pressure of 3.0 kPa for 2.5 hours, and enter S5;

[0119] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 15% g / L NaOH methanol solution, and perform alcoholysis at 52° C. for 2.5 h to obtain a modified water-soluble resin.

[0120] The method for preparing the wafer cutting protection liquid comprises the following steps:

[0121] A1. Add modified water-soluble resin, organic solvent, wetting agent, pH adjuster, ultraviolet absorber and water into a mixer;

[0122] A2. Mix for 2.5 hours at a stirring rate of 800 r / min to obtain the wafer cutting protection liquid.

[0123] Comparative Example 1

[0124] A wafer cutting protection liquid, other features of which are as in Example 3, and the weight parts of each component are shown in Table 4:

[0125] Table 4. Weight parts of each component of Comparative Example 1

[0126]

[0127]

[0128] Comparative Example 2

[0129] A wafer cutting protection liquid, other features of which are as in Example 3, and the weight parts of each component are shown in Table 5:

[0130] Table 5. Weight parts of each component of Comparative Example 2

[0131]

[0132] Comparative Example 3

[0133] A wafer cutting protection liquid, other features of which are as in Example 3, and the weight parts of each component are shown in Table 6:

[0134] Table 6. Weight parts of each component of Comparative Example 3

[0135]

[0136] Comparative Example 4

[0137] A wafer cutting protection liquid, other features of which are as in Example 3, and the weight parts of each component are as shown in Table 7:

[0138] Table 7. Weight parts of each component of Comparative Example 4

[0139]

[0140]

[0141] Comparative Example 5

[0142] A wafer cutting protection liquid, other features of which are the same as those of Example 3. The modified water-soluble resin in this comparative example uses polyvinyl alcohol, and the molecular weight of the polyvinyl alcohol is 3000-4000.

[0143] The preparation method of the wafer cutting protection liquid in this comparative example is prepared by the following steps:

[0144] A1. Add polyvinyl alcohol, organic solvent, wetting agent, pH adjuster, ultraviolet absorber and water into a blender;

[0145] A2. Mix for 2.5 hours at a stirring rate of 800 r / min to obtain the wafer cutting protection liquid.

[0146] Comparative Example 6

[0147] A wafer cutting protection liquid, other features of which are the same as those of Example 3, except that ethyl-3-(1-pyrrolidinyl) ethyl acrylate is not added to the modified water-soluble resin. The weight parts of each component are shown in Table 8:

[0148] Table 8. Weight parts of each component of Comparative Example 6

[0149]

[0150]

[0151] Wherein, the modified water-soluble resin is prepared by the following steps:

[0152] S1. Add 3,3-dimethacrylate under nitrogen protection and control the temperature to 55° C. to obtain a mixed solution;

[0153] S2, adding vinyl acetate to methanol I, controlling the temperature at 2°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 2°C, to obtain solution II; adding an initiator and 3,3-dimethacrylate methyl to methanol I, controlling the temperature at 2°C, to obtain solution I;

[0154] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 55°C to 57°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both for 45 minutes, and then entering S4;

[0155] S4, continue the reaction for 6 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 42° C. and a pressure of 3.0 kPa for 2.5 hours, and enter S5;

[0156] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 15% g / L NaOH methanol solution, and perform alcoholysis at 52° C. for 2.5 h to obtain a modified water-soluble resin.

[0157] Comparative Example 7

[0158] A wafer cutting protection liquid, other features of which are the same as those of Example 3, except that no vinyl acetate is added to the modified water-soluble resin. The weight parts of each component are shown in Table 9:

[0159] Table 9. Weight parts of each component of Comparative Example 7

[0160]

[0161] Wherein, the modified water-soluble resin is prepared by the following steps:

[0162] S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 55° C., and obtain a mixed solution;

[0163] S2, adding the initiator to methanol II, controlling the temperature at 2°C, to obtain solution II;

[0164] S3, controlling the temperature of the mixed solution obtained in S1 to be in the range of 55°C to 57°C, then adding solution I to the mixed solution for 45 minutes, and entering S4;

[0165] S4, continue the reaction for 6 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 42° C. and a pressure of 3.0 kPa for 2.5 hours, and enter S5;

[0166] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 15% g / L NaOH methanol solution, and perform alcoholysis at 52° C. for 2.5 h to obtain a modified water-soluble resin.

[0167] Comparative Example 8

[0168] A wafer cutting protection liquid, other features of which are the same as those of Example 3, except that 3,3-dimethacrylate is not added to the modified water-soluble resin. The weight parts of each component are shown in Table 10:

[0169] Table 10. Weight parts of each component of Comparative Example 8

[0170]

[0171] Wherein, the modified water-soluble resin is prepared by the following steps:

[0172] S1. Add ethyl-3-(1-pyrrolidinyl)acrylate under nitrogen protection and control the temperature to 55° C. to obtain a mixed solution;

[0173] S2, adding vinyl acetate to methanol I, controlling the temperature at 2°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 2°C, to obtain solution II;

[0174] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 55°C to 57°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both for 45 minutes, and then entering S4;

[0175] S4, continue the reaction for 6 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 42° C. and a pressure of 3.0 kPa for 2.5 hours, and enter S5;

[0176] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 15% g / L NaOH methanol solution, and perform alcoholysis at 52° C. for 2.5 h to obtain a modified water-soluble resin.

[0177] Comparative Example 9

[0178] A wafer cutting protection liquid, other features of which are the same as those of Example 3, except that the preparation steps of the modified water-soluble resin are different:

[0179] Wherein, the weight parts of each component are shown in Table 11:

[0180] Table 11. Weight parts of each component of Comparative Example 9

[0181]

[0182] S1. Add vinyl acetate, methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 55° C., and obtain a mixed solution;

[0183] S2, adding the initiator to methanol II, controlling the temperature at 2°C, to obtain solution II;

[0184] S3, controlling the temperature of the mixed solution obtained in S1 within the range of 55°C to 57°C, and then adding solution II to the mixed solution at the same time for 45 minutes, and then proceeding to S4;

[0185] S4, continue the reaction for 6 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 42° C. and a pressure of 3.0 kPa for 2.5 hours, and enter S5;

[0186] S5. Dissolve the copolymer obtained in S4 in methanol III, add a 15% g / L NaOH methanol solution, and perform alcoholysis at 52° C. for 2.5 h to obtain a modified water-soluble resin.

[0187] Effect example

[0188] 1. Film forming time test

[0189] 35 ml of the wafer cutting protection liquid of Examples 1 to 3 and Comparative Examples 1-9 were respectively spun on the surface of a 12-inch bare silicon wafer using a spin coater, and then a protective film was formed at 30°C. The time from the completion of spin coating to complete drying was measured, which was the film formation time, as shown in Table 12.

[0190] Table 12, Film Formation Time

[0191]

[0192]

[0193] Note: ND means no film formation.

[0194] It can be seen from the data in Table 12 that the film forming time of the wafer cutting protection liquid obtained in Examples 1 to 3 is equivalent to the film forming time of Comparative Example 5, and is significantly better than the wafer cutting protection liquid obtained in Comparative Example 8 and Comparative Example 7, thus proving that the wafer cutting protection liquid of the present invention can form a film quickly.

[0195] 2. Cleaning test

[0196] Step 1, 35 ml of the wafer cutting protection liquid of Examples 1 to 3 and Comparative Examples 1-9 are respectively spun on the surface of a 12-inch bare silicon wafer through a spin coater, and then the spin coating is completed at 30° C. until it is completely dried to obtain the corresponding spin-coated wafer;

[0197] Step 2: Wash with ultrapure water, and then rotate at 1000 r / min to evaporate the water;

[0198] Step 3: Measure and calculate the carbon content per unit area of ​​the bare silicon wafer surface after cleaning by SEM-EDX energy spectrum method. The carbon content is shown in Table 12.

[0199] Table 13, Carbon content

[0200]

[0201]

[0202] It can be seen from Table 13 that the protective film layer formed by the wafer cutting protection liquid obtained in Examples 1 to 3 can be completely removed by using pure water.

[0203] 3. Wafer laser cutting test

[0204] 3.1. Perform laser cutting of silicon wafers according to the following steps:

[0205] S1, spin coating the wafer cutting protection liquid of Examples 1 to 3 and Comparative Examples 1-9 on the surface of a silicon wafer, and drying at 30° C. to form a protection film with a thickness of 2±0.5 μm;

[0206] S2, During the cutting test, nanosecond pulse laser was used for cutting, and the parameters were selected as 355nm, frequency 40KHz, scribing speed 200mm / s, cutting width 40um, and power 3.5W;

[0207] S3. The cut silicon wafer is cleaned with ultrapure water, and after cleaning, it is rotated at 1300 r / min to evaporate the water, thereby completing the laser cutting and observing the sintering condition, as shown in Table 14.

[0208] Table 14. Cutting performance and sintering of laser cutting

[0209]

[0210] Through Table 13 and Figures 1 to 4 After the wafer cutting protection liquid obtained in Examples 1 to 3 forms a protective film on the wafer, the cutting line cut at a power of 3.5 W is straight and has no edge collapse, and there is no sintering phenomenon after cleaning, which is significantly better than the wafer cutting protection liquid of Comparative Examples 1 to 9. Therefore, it is proved that the wafer cutting protection liquid of the present invention effectively protects the wafer, and the cutting line is straight and has no edge collapse even after laser cutting; and it can effectively reduce carbide residue, and there is still no sintering phenomenon even after cutting and cleaning.

[0211] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A wafer cutting protection liquid, characterized in that: The raw materials contain modified water-soluble resin, organic solvent, wetting agent, pH adjuster, ultraviolet absorber and water; The modified water-soluble resin is prepared by free radical polymerization of vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and 3,3-methyl dimethacrylate to obtain a copolymer, and then alcoholysis of the copolymer is performed to obtain the modified polyvinyl alcohol.

2. The wafer cutting protection liquid according to claim 1, characterized in that: In parts by weight, Modified water-soluble resin: 30 to 50 parts; Organic solvent: 10 to 20 parts; Wetting agent: 1 to 3 parts; pH adjuster: 0.5 to 2 parts; Ultraviolet absorber: 1 to 5 parts; The balance is water, and the total amount of all components is calculated as 100 parts.

3. The wafer cutting protection liquid according to claim 2, characterized in that: In parts by weight, Modified water-soluble resin: 42.5 parts; Organic solvent: 15 parts; Wetting agent: 2.3 parts; pH regulator: 1.2 parts; Ultraviolet light absorber: 3.5 parts; The balance is water, and the total amount of all components is calculated as 100 parts.

4. The wafer cutting protection liquid according to any one of claims 1 to 3, characterized in that: In the modified water-soluble resin, in parts by weight, Vinyl acetate: 30 to 50 parts; Ethyl 3-(1-pyrrolidinyl)acrylate: 5 to 10 parts; 3,3-dimethacrylate methyl ester: 3 to 8 parts; Methanol I: 50 to 80 parts; Methanol II: 20 to 50 parts; Methanol III: 100 to 200 parts; NaOH methanol solution: 100 to 150 parts; Initiator: 0.1 to 1 part.

5. The wafer cutting protection liquid according to claim 4, characterized in that: In the modified water-soluble resin, in parts by weight, Vinyl acetate: 40 parts; Ethyl-3-(1-pyrrolidinyl)acrylate: 6.7 parts; 3,3-dimethacrylate methyl ester: 4.6 parts; Methanol I: 60 parts; Methanol II: 30 parts; Methanol III: 150 parts; NaOH methanol solution: 135 parts; Initiator: 0.8 parts.

6. The wafer cutting protection liquid according to claim 5, characterized in that: The modified water-soluble resin is prepared by the following steps: S1, mixing vinyl acetate and ethyl-3-(1-pyrrolidinyl)acrylate to obtain a mixed solution; S2, adding an initiator and methyl 3,3-dimethacrylate into methanol I to obtain solution I; S3, adding solution I to the mixed solution obtained in S1 at a constant rate, and entering S4; S4, continue the reaction to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) ethyl acrylate and methyl 3,3-dimethacrylate, distill under reduced pressure, and enter S5; S5. Dissolve the copolymer obtained in S4 in methanol III, add NaOH methanol solution to perform alcoholysis to obtain a modified water-soluble resin.

7. The wafer cutting protection liquid according to claim 6, characterized in that: The modified water-soluble resin is prepared by the following steps: S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 50° C. to 60° C., and obtain a mixed solution; S2, adding vinyl acetate to methanol I, controlling the temperature at 0°C to 5°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 0°C to 5°C, to obtain solution II; S3, controlling the temperature of the mixed solution obtained in S1 within the range of 50°C to 60°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both of which are 30min to 60min, and then entering S4; S4, continue the reaction for 5h to 8h to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl)acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 30°C to 60°C and a pressure of 1.5 kPa to 3.0 kPa for 2h to 3h, and enter S5; S5. Dissolve the copolymer obtained in S4 in methanol III, add a 10% g / L-20% g / L NaOH methanol solution, and perform alcoholysis at a temperature of 40°C to 60°C for 2h to 3h to obtain a modified water-soluble resin.

8. The wafer cutting protection liquid according to claim 7, characterized in that: The modified water-soluble resin is prepared by the following steps: S1. Add methyl 3,3-dimethacrylate and ethyl 3-(1-pyrrolidinyl)acrylate under nitrogen protection, control the temperature to 55° C., and obtain a mixed solution; S2, adding vinyl acetate to methanol I, controlling the temperature at 2°C, to obtain solution I; adding an initiator to methanol II, controlling the temperature at 2°C, to obtain solution II; S3, controlling the temperature of the mixed solution obtained in S1 within the range of 55°C to 57°C, and then adding solution I and solution II to the mixed solution at the same time, and the adding time of solution I and solution II is the same, both for 45 minutes, and then entering S4; S4, continue the reaction for 6 hours to obtain a copolymer of vinyl acetate, ethyl-3-(1-pyrrolidinyl) acrylate and methyl 3,3-dimethacrylate, distill at a temperature of 42° C. and a pressure of 3.0 kPa for 2.5 hours, and enter S5; S5. Dissolve the copolymer obtained in S4 in methanol III, add a 15% g / L NaOH methanol solution, and perform alcoholysis at 52° C. for 2.5 h to obtain a modified water-soluble resin.

9. The wafer cutting protection liquid according to claim 4, characterized in that: The initiator is azobisisobutyronitrile, dimethyl azobisisobutyrate or di-tert-butyl peroxide; The wetting agent is an acrylic leveling agent; The pH regulator is N,N-dimethylethanolamine; The organic solvent is ethylene glycol methyl ether, propylene glycol methyl ether or dioxane; The ultraviolet absorber is o-hydroxybenzophenone, benzotriazole or salicylate.

10. A method for preparing a wafer cutting protection liquid according to any one of claims 1 to 9, characterized in that: Prepared by the following steps: A1. Add modified water-soluble resin, organic solvent, wetting agent, pH adjuster, ultraviolet absorber and water into a mixer; A2. Mix for 2 h to 3 h at a stirring rate of 500 r / min to 1000 r / min to obtain the wafer cutting protection liquid.

Images