Hydrofluoric acid etching resistant protective glue and preparation method thereof

Abstract

The invention relates to the technical field of acid-resistant protective glue, in particular to hydrofluoric acid etching resistant protective glue and a preparation method thereof. The hydrofluoric acid etching resistant protective glue is prepared from the following raw materials in parts by weight: 58-78 parts of a main monomer; 7-13 parts of an adjusting monomer; 16 to 29 parts of a functional monomer; 20 to 30 parts of a fluorine-containing monomer; 0.2 to 0.4 part of an initiator; 0.2 to 1 part of an auxiliary agent; 130 to 150 parts of an organic solvent; the organic solvent comprises ethyl acetate and methylbenzene. According to the invention, the specific fluorine-containing monomer is introduced, the dosage ratio of the raw materials is strictly controlled, and through the synergistic effect of the fluorine-containing monomer and various monomers in the system, the high adhesive force is ensured, meanwhile, the good hydrofluoric acid corrosion resistance is achieved, and the acid seepage phenomenon does not occur in the chip etching production;

Description

Technical Field

[0001] The present invention relates to the technical field of acid-resistant protective adhesives, and particularly relates to a hydrofluoric acid-resistant etching protective adhesive and a preparation method thereof. Background Art

[0002] Hydrofluoric acid-resistant etching protective adhesives play a crucial role in multiple high-tech fields such as precision machining, optical device manufacturing, and semiconductor production. Such protective adhesives are designed to cover the surface of workpieces before the etching process, effectively isolating the workpiece material from the etching agent and ensuring the accuracy and quality of the final product. During application, the key lies in ensuring that the protective adhesive can closely adhere to the workpiece, forming a strong protective barrier. Once coated, this protective adhesive will act as a barrier layer during subsequent etching operations, preventing the etching agent from directly contacting and damaging the workpiece, thereby achieving effective protection of the workpiece.

[0003] Generally, the colloid is applied to the release film by coating, and then transferred to a specific film by film transfer. During the chip etching process, the protective film is attached to the wafer to be protected, and acid etching operations are performed. The whole process takes several minutes. The etching working fluid consists of strong acids such as concentrated sulfuric acid, nitric acid, hydrofluoric acid, and hydrochloric acid. For some special processes, the proportion of hydrofluoric acid will increase significantly, which poses additional requirements for the performance of the acid-resistant etching protective adhesive: during the etching operation, the protective film and the bonding edge between it and the wafer must be absolutely sealed to prevent any acidic liquid from penetrating, ensuring that the protected components can be protected from strong acids and thus smoothly completing the chip manufacturing process.

[0004] Currently, the etching protective adhesive is provided by Japan and has high performance. Whether it is acid-resistant protection or adhesion to the wafer, it is stable without residual glue and has relatively prominent performance. However, there is less research on hydrofluoric acid-resistant etching protective adhesives in China at present. For example, Chinese Patent Application CN104497204A discloses an alkali-soluble resin and a UV-curable hydrofluoric acid-resistant protective adhesive composition containing the alkali-soluble resin. The alkali-soluble resin is a prepolymer formed by maleic anhydride or methyl maleic anhydride structural units, unsaturated carboxylic acid ester structural units, and / or aromatic vinyl structural units. However, on the one hand, its adhesion to the substrate is insufficient, and on the other hand, the density of the protective film after curing is not enough, resulting in the penetration of acid liquid through the protective film and thus corrosion of the substrate. These problems seriously affect the use effect of the hydrofluoric acid-resistant etching protective adhesive and the production quality of the chips. Summary of the Invention

[0005] To solve the problems in the prior art, in the first aspect of the present invention, a hydrofluoric acid-resistant etching protective adhesive is provided. Calculated by weight parts, the raw materials for preparing the hydrofluoric acid-resistant etching protective adhesive include:

[0006] 58 - 78 parts of main monomer;

[0007] 7 - 13 parts of the regulating monomer;

[0008] 16 - 29 parts of the functional monomer;

[0009] 20 - 30 parts of the fluorine - containing monomer;

[0010] 0.2 - 0.4 parts of the initiator;

[0011] 0.2 - 1 part of the auxiliary agent;

[0012] 130 - 150 parts of the organic solvent;

[0013] The organic solvent includes ethyl acetate and toluene.

[0014] In one embodiment, the mass ratio of the main monomer to the regulating monomer is (65 - 70):(9 - 11). Examples can be 65:9, 65:11, 68:10, 69:10, 70:11.

[0015] In one embodiment, the main monomer includes butyl acrylate.

[0016] In one embodiment, the regulating monomer includes butyl methacrylate.

[0017] In one embodiment, the functional monomer includes at least one of acrylic acid, methacrylic acid, 2 - hydroxyethyl methacrylate, and glycidyl acrylate. Preferably, the functional monomer includes acrylic acid, methacrylic acid, 2 - hydroxyethyl methacrylate, and glycidyl acrylate.

[0018] In a preferred embodiment, the mass ratio of acrylic acid, methacrylic acid, 2 - hydroxyethyl methacrylate, and glycidyl acrylate is (0.2 - 0.3):(0.5 - 1):(1 - 2):(15 - 25). Examples can be 0.2:0.5:1:15, 0.25:0.75:1.5:20, 0.3:1:2:25.

[0019] In one embodiment, the fluorine - containing monomer includes 2 - fluoroacrylic acid.

[0020] In one embodiment, the auxiliary agent includes at least one of a radical inhibitor and a catalyst. Preferably, the auxiliary agent includes a radical inhibitor and a catalyst.

[0021] In a preferred embodiment, the mass ratio of the radical inhibitor to the catalyst is (1 - 5):(1 - 5). Examples can be 2:1, 3:1, 5:1.

[0022] In a preferred embodiment, the free radical polymerization inhibitor includes hydroquinone; the catalyst includes tetramethylammonium chloride.

[0023] In one embodiment, the initiator includes at least one of azobisisobutyronitrile, azobisisoheptonitrile, and benzoyl peroxide. Preferably, the initiator includes azobisisobutyronitrile.

[0024] In one embodiment, the mass ratio of ethyl acetate to toluene is (10 - 13):2. Examples can be 10:2, 11:2, 12:2, 13:2.

[0025] The second aspect of the present invention provides a preparation method of a hydrofluoric acid resistant etching protective glue, which at least includes the following steps:

[0026] Put the main monomer, regulating monomer, functional monomer, and ethyl acetate into a reaction kettle, stir and heat to 70 °C to obtain mixture A;

[0027] Add 60 - 70 wt% of the initiator to mixture A, raise the temperature and react for 4 - 5 h to obtain mixture B;

[0028] Add the remaining initiator to mixture B, raise the temperature for the second time and react for 2 - 3 h, then add toluene, fluorine-containing monomer, and additives and continue to react for 8 - 9 h. After cooling to room temperature, filter and package to obtain the hydrofluoric acid resistant etching protective glue.

[0029] In one embodiment, the conditions for the temperature-raising reaction are to raise the temperature to 80 °C and the reaction time is 4.5 h.

[0030] In one embodiment, the conditions for the second temperature-raising reaction are to raise the temperature to 90 °C and the reaction time is 2.5 h.

[0031] Beneficial effects

[0032] 1. The present invention introduces specific fluorine-containing monomers, strictly controls the dosage ratio between various raw materials, and through the synergistic effect with various monomers in the system, while ensuring a relatively high adhesive force, has good hydrofluoric acid corrosion resistance, and no acid leakage phenomenon occurs in chip etching production.

[0033] 2. The present invention selects specific main monomers and regulating monomers. Specifically, the main monomer is butyl acrylate, the regulating monomer is butyl methacrylate, and controls their mass ratio to be (65 - 70):(9 - 11), which can effectively prevent the residual glue phenomenon that occurs after the protective film made of the hydrofluoric acid resistant etching protective glue is peeled off.

[0034] 3. The preparation method of the hydrofluoric acid resistant etching protective glue provided by the present invention can effectively prevent the generation of glue shadows on the stainless steel plate by controlling the addition method of the initiator and the reaction temperature.

[0035] 4. Through specific monomer selection, the present invention maintains the weight-average molecular weight of the system between 200,000 and 300,000, enabling the protective colloid to achieve a balance among adhesion, residual glue, and acid corrosion resistance. Description of the Drawings

[0036] Figure 1 It is a test chart of residual glue for Example 1.

[0037] Figure 2 It is a test chart of etching protection force for Example 1.

[0038] Figure 3 It is a test chart of residual glue for Comparative Example 1.

[0039] Figure 4 It is a test chart of etching protection force for Comparative Example 2.

[0040] Figure 5 It is a test chart of residual glue for Comparative Example 3. Detailed Embodiments

[0041] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The experimental methods without specific conditions noted in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments without the manufacturer noted are all conventional products that can be obtained through commercial purchase.

[0042] In the present invention: butyl acrylate, butyl methacrylate, acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate, glycidyl acrylate, and 2-fluoroacrylic acid all come from Shanghai Macklin Biochemical Co., Ltd.; hydroquinone, tetramethylammonium chloride, azobisisobutyronitrile, ethyl acetate, and toluene all come from Sinopharm Chemical Reagent Co., Ltd.

[0043] Example 1

[0044] In the first aspect of this example, a hydrogen fluoride-resistant etching protective colloid is provided. Calculated by weight parts, the raw materials for preparing the hydrogen fluoride-resistant etching protective colloid include:

[0045] 68 parts of main monomer;

[0046] 10 parts of regulating monomer;

[0047] 22.5 parts of functional monomer;

[0048] 20 parts of fluorine-containing monomer;

[0049] 0.3 part of initiator;

[0050] 0.4 parts of auxiliary agent;

[0051] 140 parts of organic solvent;

[0052] The organic solvent is ethyl acetate and toluene. The mass ratio of ethyl acetate to toluene is 12:2.

[0053] The functional monomers are acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate and glycidyl acrylate. The mass ratio of acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate and glycidyl acrylate is 0.25:0.75:1.5:20.

[0054] The auxiliary agent is hydroquinone and tetramethylammonium chloride. The mass ratio of hydroquinone to tetramethylammonium chloride is 3:1.

[0055] The main monomer is butyl acrylate. The regulating monomer is butyl methacrylate. The fluorine-containing monomer is 2-fluoroacrylic acid. The initiator is azobisisobutyronitrile.

[0056] In the second aspect of this embodiment, a preparation method of a hydrofluoric acid etching-resistant protective glue is provided, which at least includes the following steps:

[0057] Put the main monomer, regulating monomer, functional monomer and ethyl acetate into a reaction kettle, stir and heat to 70 °C to obtain mixture A;

[0058] Add 0.2 parts of initiator to mixture A, raise the temperature to 80 °C and react for 4.5 h to obtain mixture B;

[0059] Add the remaining initiator to mixture B, raise the temperature to 90 °C and react for 2.5 h, then add toluene, fluorine-containing monomer and auxiliary agent and continue to react for 8 h. After cooling to room temperature, filter and package to obtain the hydrofluoric acid etching-resistant protective glue.

[0060] Figure 1 It is the residual glue test chart of Example 1; Figure 2 It is the etching protection force test chart of Example 1.

[0061] Comparative Example 1

[0062] In the first aspect of this comparative example, a protective glue is provided. Calculated by weight parts, the raw materials for preparing the protective glue include:

[0063] 68 parts of main monomer;

[0064] 10 parts of regulating monomer;

[0065] 22.5 parts of functional monomer;

[0066] 20 parts of fluorine-containing monomer;

[0067] 0.3 parts of initiator;

[0068] 0.4 parts of additives;

[0069] 140 parts of organic solvent;

[0070] The organic solvent is ethyl acetate and toluene, and the mass ratio of ethyl acetate to toluene is 12:2.

[0071] The functional monomers are acrylic acid, methacrylic acid, hydroxyethyl methacrylate and glycidyl acrylate, and the mass ratio of acrylic acid, methacrylic acid, hydroxyethyl methacrylate and glycidyl acrylate is 0.25:0.75:1.5:20.

[0072] The auxiliary agent is hydroquinone and tetramethylammonium chloride, and the mass ratio of hydroquinone to tetramethylammonium chloride is 3:1.

[0073] The main monomer is isooctyl acrylate, the regulating monomer is methyl methacrylate, the fluorine-containing monomer is 2-fluoroacrylic acid, and the initiator is azobisisobutyronitrile.

[0074] The second aspect of this comparative example provides a method for preparing a protective glue, which at least comprises the following steps:

[0075] Put the main monomer, regulating monomer, functional monomer and ethyl acetate into a reaction kettle, stir and heat to 70°C to obtain a mixture A;

[0076] 0.2 parts of initiator was added to mixture A, and the temperature was raised to 80°C and reacted for 4.5 hours to obtain mixture B;

[0077] The remaining initiator is added to the mixture B, the temperature is raised to 90° C. and the mixture is reacted for 2.5 hours, toluene, fluorine-containing monomer and auxiliary agent are added, and the mixture is reacted for 8 hours. The mixture is cooled to room temperature and filtered and packaged to obtain the hydrofluoric acid etching resistant protective glue.

[0078] Figure 3 This is the residual glue test question for Comparative Example 1.

[0079] Comparative Example 2

[0080] The first aspect of this comparative example provides a protective glue, and the raw materials for preparing the protective glue include, by weight:

[0081] 68 parts of main monomer;

[0082] Adjust the monomer to 10 parts;

[0083] 22.5 parts of functional monomer;

[0084] 20 parts of C9 petroleum resin;

[0085] 0.3 parts of initiator;

[0086] 0.4 parts of auxiliary agent;

[0087] 140 parts of organic solvent;

[0088] The organic solvent is ethyl acetate and toluene. The mass ratio of ethyl acetate to toluene is 12:2.

[0089] The functional monomer is acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate and glycidyl acrylate. The mass ratio of acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate and glycidyl acrylate is 0.25:0.75:1.5:20.

[0090] The auxiliary agent is hydroquinone and tetramethylammonium chloride. The mass ratio of hydroquinone to tetramethylammonium chloride is 3:1.

[0091] The main monomer is isooctyl acrylate. The regulating monomer is methyl methacrylate. The fluorine-containing monomer is 2-fluoroacrylic acid. The initiator is azobisisobutyronitrile.

[0092] The second aspect of this comparative example provides a method for preparing a protective glue, which at least includes the following steps:

[0093] Put the main monomer, regulating monomer, functional monomer and ethyl acetate into a reaction kettle, stir and heat to 70 °C to obtain mixture A;

[0094] Add 0.2 parts of initiator to mixture A, raise the temperature to 80 °C and react for 4.5 h to obtain mixture B;

[0095] Add the remaining initiator to mixture B, raise the temperature to 90 °C and react for 2.5 h, then add toluene, C9 petroleum resin and auxiliary agent and continue to react for 8 h. After cooling to room temperature, filter and package to obtain the hydrofluoric acid etching-resistant protective glue.

[0096] Figure 4 It is the etching protection force test chart of Comparative Example 2.

[0097] Comparative Example 3

[0098] The first aspect of this comparative example provides a protective glue. Calculated by weight parts, the raw materials for preparing the protective glue include:

[0099] 80 parts of main monomer;

[0100] 4 parts of regulating monomer;

[0101] 22.5 parts of functional monomer;

[0102] 20 parts of fluorine-containing monomer;

[0103] 0.5 parts of initiator;

[0104] 0.4 parts of auxiliary agent;

[0105] 140 parts of organic solvent;

[0106] The organic solvent is ethyl acetate and toluene. The mass ratio of ethyl acetate to toluene is 12:2.

[0107] The functional monomer is acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate and glycidyl acrylate. The mass ratio of acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate and glycidyl acrylate is 0.25:0.75:1.5:20.

[0108] The auxiliary agent is hydroquinone and tetramethylammonium chloride. The mass ratio of hydroquinone to tetramethylammonium chloride is 3:1.

[0109] The main monomer is isooctyl acrylate. The regulating monomer is methyl methacrylate. The fluorine-containing monomer is 2-fluoroacrylic acid. The initiator is azobisisobutyronitrile.

[0110] The second aspect of this comparative example provides a preparation method of a protective glue, which at least includes the following steps:

[0111] Put the main monomer, regulating monomer, functional monomer and ethyl acetate into a reaction kettle, stir and heat to 70 °C to obtain mixture A;

[0112] Add 0.4 parts of initiator to mixture A, raise the temperature to 90 °C and react for 4.5 h to obtain mixture B;

[0113] Add the remaining initiator to mixture B, raise the temperature to 100 °C and react for 2.5 h, then add toluene, fluorine-containing monomer and auxiliary agent and continue to react for 8 h. After cooling to room temperature, filter and package to obtain the hydrofluoric acid etching-resistant protective glue.

[0114] Figure 5 It is the residual glue test chart of Comparative Example 3.

[0115] Performance test

[0116] 1. Adhesion test: Use the protective glues synthesized in Example 1 and Comparative Examples 1-3 to make glue films on PO films respectively, stick them on stainless steel plates, and after 20 minutes, detect their 180-degree peel strength. The 180-degree peel strength requirement is not less than 1 N / 2.5 cm. The test refers to the national standard test GB / T 2792-2014. The test results are shown in Table 1. The preparation method of the glue film is to coat it on the PO film with a 50 μ wire bar and dry it at 50 °C for 48 h.

[0117] 2. Residual Adhesive Test: The protective adhesives synthesized in Example 1 and Comparative Examples 1-3 were made into adhesive films using the sample preparation method for adhesion testing. After pasting on a stainless steel plate and peeling off after 24 hours, observe whether there are obvious residual adhesives, residual imprints, etc. on the stainless steel plate. The test results are shown in Table 1 and Figure 1 、 3 、5.

[0118] 3. Etching Protection Force Test: The protective film was prepared in the same manner as the above residual adhesive test. During the chip production process, this film needs to protect the edges of the components from being etched and damaged by hydrofluoric acid. From Figure 2 and Figure 4 it can be seen that for the protective film prepared from the protective adhesive of the present invention, the edge of the glued film was not eroded and the components were intact, while acid leakage occurred at the edge of the silicon wafer in Comparative Example 2.

[0119] Table 1

[0120] Test item Example 1 Comparative example 1 Comparative example 2 Comparative example 3 180-degree peel strength 1.1 N / 2.5 cm 2 N / 2.5 cm 1.5 N / 2.5 cm 1.3 N / 2.5 cm Residual glue test No residual glue With residual glue No residual glue Glue shadow generated

[0121] From the data in Table 1, it can be seen that the protective adhesive prepared by the present invention achieves a balance among adhesion, residual adhesive, and acid corrosion resistance.

Claims

1. A hydrofluoric acid etching resistant protective glue, characterized in that: The raw materials for preparing the hydrofluoric acid etching resistant protective glue include, by weight: 58-78 parts of main monomer; Adjust the monomer to 7-13 parts; 16 to 29 parts of functional monomer; 20-30 parts of fluorine-containing monomer; Initiator 0.2-0.4 parts; Additives 0.2-1 part; 130-150 parts of organic solvent; The organic solvent includes ethyl acetate and toluene.

2. The hydrofluoric acid etching resistant protective glue according to claim 1, characterized in that: The mass ratio of the main monomer to the regulating monomer is (65-70):(9-11).

3. The hydrofluoric acid etching resistant protective glue according to claim 1, characterized in that: The main monomer includes butyl acrylate.

4. The hydrofluoric acid etching resistant protective glue according to claim 1, characterized in that: The regulating monomer includes butyl methacrylate.

5. The hydrofluoric acid etching resistant protective glue according to claim 1, characterized in that: The functional monomer includes at least one of acrylic acid, methacrylic acid, hydroxyethyl methacrylate, and glycidyl acrylate.

6. The hydrofluoric acid etching resistant protective glue according to claim 5, characterized in that: The mass ratio of acrylic acid, methacrylic acid, hydroxyethyl methacrylate and glycidyl acrylate is (0.2-0.3): (0.5-1): (1-2): (15-25).

7. The hydrofluoric acid etching resistant protective glue according to claim 1, characterized in that: The fluorine-containing monomer includes 2-fluoroacrylic acid.

8. The hydrofluoric acid etching resistant protective glue according to claim 1, characterized in that: The auxiliary agent includes at least one of a free radical inhibitor and a catalyst.

9. The hydrofluoric acid etching resistant protective glue according to claim 1, characterized in that: The initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile and benzoyl peroxide.

10. A method for preparing the hydrofluoric acid etching resistant protective glue according to any one of claims 1 to 9, characterized in that: At least the following steps are included: Put the main monomer, regulating monomer, functional monomer and ethyl acetate into a reaction kettle, stir and heat to 70°C to obtain a mixture A; Add 60-70 wt% of initiator to mixture A, and heat to react for 4-5 hours to obtain mixture B; The remaining initiator is added to the mixture B, and after a second heating reaction for 2 to 3 hours, toluene, fluorine-containing monomer and auxiliary agent are added, and the reaction is continued for 8 to 9 hours. After cooling to room temperature, the mixture is filtered and packaged to obtain the hydrofluoric acid etching resistant protective glue.

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