Preparation method of 248nm photoresist resin
By introducing epoxy group monomers and tertiary amine groups into the preparation method of 248nm photoresist resin, the problems of high metal impurities content, insufficient etching resistance and light transmittance in the existing photoresist resin are solved, and higher photolithography precision and stability are achieved.
Patent Information
- Application Number
- CN202411969070.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-03-11
AI Technical Summary
The existing 193nm photoresist resin has problems in high-precision photolithography process, high metal impurity content, insufficient etch resistance and light transmittance, and the photoacid generator diffuses after light decomposition, resulting in a decrease in the precision of the boundary between the exposure and non-exposure zones.
Using the preparation method of 248nm photoresist resin, the epoxy group monomer is introduced as a styrene derivative during the resin synthesis process, and the tertiary amine is introduced in the final step and the electron-grade secondary amine compound reaction is formed to form a resin solution with tertiary amine groups.
The basic structure, etch resistance and light transmittance of the resin are achieved, while the oxidation yellowing problems caused by the increase in metal ion content and the advance introduction of amine groups are avoided, and the precision and stability of the photoresist are improved.
Smart Images
Figure FT_1
Abstract
Description
Technical Field
[0001] The invention relates to the field of photoresists, and in particular to a method for preparing a 248nm photoresist resin. Background Art
[0002] Polymethacrylate resin has good light transmittance and excellent etching resistance, and is used as a film-forming resin in semiconductor photoresist compositions. 193nm photoresist uses a 193nm light source, and benzene rings absorb in this band, competing with photoacid generation for light absorption, so all 193nm photoresist resins cannot use benzene ring monomers. In order to make the photoresist have better etching resistance, rigid groups such as ring structures need to be used.
[0003] High-precision integrated circuits have very high requirements on the metal impurity content of semiconductor photoresists, which requires that the metal impurity content of the film-forming resin in the corresponding components should be as low as possible, with the single metal impurity content required to be <1ppb and the total metal impurity content required to be <10ppb.
[0004] After the conventional 193nm resin is prepared, it will be configured with other resins, photoacid generators, additives, solvents, etc. to form a photoresist solution for use in the photolithography process. The photoacid generator is generally added at 0.1% to 2%, and produces super strong proton acid under light conditions, which acid-decomposes the acid-decomposable groups in the photoresist resin, improves the alkali solubility of the resin, achieves the solubility difference between the exposed and non-exposed areas, and achieves the purpose of etching. After the photoacid is decomposed by light, it will diffuse in the film, resulting in a decrease in the precision of the boundary between the exposed and non-exposed areas. For photolithography processes with high requirements for etching accuracy, a small amount of organic amine will be added to neutralize a small amount of diffused acid, thereby suppressing this side effect. However, the front-end process of photoresist includes coating, baking, exposure, development, and post-baking. In these processes, small molecules of organic amines will be volatilized, affecting the equipment and environment in the photolithography process. Summary of the invention
[0005] The purpose of the present invention is to provide a method for preparing a 248nm photoresist resin.
[0006] The innovation of the present invention is that the epoxy group monomer introduced in the resin synthesis process is a styrene derivative, which will not affect the basic structure, etching resistance, light transmittance, etc. of the resin. Since it is synthesized on the resin, it will not volatilize in the later stage.
[0007] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is: A method for preparing a 248nm photoresist resin comprises the following steps: (1) synthesizing a resin to obtain a synthetic resin solution, wherein the synthesized monomers include the following raw materials in molar percentages: 50-99.99% 4-acetoxystyrene, 0-49.99% styrene, and 0.01-0.1% epoxy derivatives of styrene; (2) removing impurities and unreacted monomers from the synthetic resin solution to obtain a No. 1 resin solution; (3) hydrolyzing the No. 1 resin solution to obtain the No. 2 resin solution; (4) removing metal impurities from the No. 2 resin solution to obtain a No. 3 resin solution; (5) replacing the solvent in the No. 3 resin solution with an electronic grade solvent to obtain a No. 4 resin solution; (6) An electronic grade secondary amine compound is added to the No. 4 resin solution to generate a resin solution with a tertiary amine group, wherein the molar amount of the electronic grade secondary amine compound is 95-100% of the molar amount of the epoxy derivative of styrene.
[0008] Furthermore, the epoxy derivative of styrene is one of 4-glycidyl ether styrene and p-vinylbenzyl glycidyl ether.
[0009] Furthermore, the electronic grade secondary amine compound is one of morpholine, N-phenylethylamine and indoline.
[0010] Furthermore, in the step (1), the resin is synthesized by free radical polymerization to obtain a synthetic resin solution.
[0011] Furthermore, the electronic grade solvent is one of propylene glycol methyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, diethylene glycol methyl ethyl ether, and cyclohexanone.
[0012] The beneficial effects of the present invention are: 1. The epoxy group monomer introduced in the resin synthesis process of the present invention is a styrene derivative, which will not affect the basic structure, etching resistance, light transmittance, etc. of the resin. Since it is synthesized on the resin, it will not volatilize in the later stage.
[0013] 2. In the present invention, the metal ion content in the resin will not be increased by reacting the electronic grade secondary amine with the epoxy in the resin.
[0014] 3. The introduction of tertiary amine in the present invention is the last step in the production of resin. The reaction is carried out under mild conditions and will not affect the synthesis of the resin. The premature introduction of amine groups can avoid oxidation and yellowing during the resin synthesis process. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a comparison of conventional resin (above) and the resin of Example 1 (below) after photolithography. DETAILED DESCRIPTION
[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below.
[0017] Embodiment 1: A method for preparing a 248nm photoresist resin comprises the following steps: synthesizing a resin to obtain a synthetic resin solution, wherein the monomers synthesized during the synthesis include the following raw materials in molar percentage: 99.99% 4-acetoxystyrene and 0.01% epoxy derivatives of styrene; removing impurities and unreacted monomers in the synthetic resin solution to obtain a No. 1 resin solution; hydrolyzing the No. 1 resin solution to obtain a No. 2 resin solution; removing metal impurities in the No. 2 resin solution to obtain a No. 3 resin solution; replacing the solvent in the No. 3 resin solution with an electronic grade solvent to obtain a No. 4 resin solution; and generating a resin solution with a tertiary amine group by adding an electronic grade secondary amine compound to the No. 4 resin solution, wherein the molar amount of the electronic grade secondary amine compound is 95% of the molar amount of the epoxy derivative of styrene.
[0018] The epoxy derivative of styrene is 4-glycidyl ether styrene.
[0019] The electronic grade secondary amine compound is morpholine.
[0020] The electronic grade solvent is propylene glycol methyl ether acetate.
[0021] During the resin synthesis, free radical polymerization is adopted to obtain a synthetic resin solution.
[0022] Embodiment 2: A method for preparing a 248nm photoresist resin comprises the following steps: synthesizing a resin to obtain a synthetic resin solution, wherein the monomers synthesized during the synthesis include the following raw materials in molar percentage: 50% 4-acetoxystyrene, 49.99% styrene, and 0.01% epoxy derivatives of styrene; removing impurities and unreacted monomers in the synthetic resin solution to obtain a No. 1 resin solution; hydrolyzing the No. 1 resin solution to obtain a No. 2 resin solution; removing metal impurities in the No. 2 resin solution to obtain a No. 3 resin solution; replacing the solvent in the No. 3 resin solution with an electronic grade solvent to obtain a No. 4 resin solution; and generating a resin solution with a tertiary amine group by adding an electronic grade secondary amine compound to the No. 4 resin solution, wherein the molar amount of the electronic grade secondary amine compound is 96% of the molar amount of the epoxy derivative of styrene.
[0023] The epoxy derivative of styrene is p-vinylbenzyl glycidyl ether.
[0024] The electronic grade secondary amine compound is N-phenylethylamine.
[0025] The electronic grade solvent was ethyl lactate.
[0026] Embodiment 3: A method for preparing a 248nm photoresist resin comprises the following steps: synthesizing a resin to obtain a synthetic resin solution, wherein the monomers synthesized during the synthesis include the following raw materials in molar percentages: 85% 4-acetoxystyrene, 14.9% styrene, and 0.1% epoxy derivatives of styrene; removing impurities and unreacted monomers in the synthetic resin solution to obtain a No. 1 resin solution; hydrolyzing the No. 1 resin solution to obtain a No. 2 resin solution; removing metal impurities in the No. 2 resin solution to obtain a No. 3 resin solution; replacing the solvent in the No. 3 resin solution with an electronic grade solvent to obtain a No. 4 resin solution; and adding an electronic grade secondary amine compound to the No. 4 resin solution to react to generate a resin solution with a tertiary amine group, wherein the molar amount of the electronic grade secondary amine compound is 98% of the molar amount of the epoxy derivative of styrene.
[0027] The epoxy derivative of styrene is 4-glycidyl ether styrene.
[0028] The electronic grade secondary amine compound is indoline.
[0029] During the resin synthesis, free radical polymerization is adopted to obtain a synthetic resin solution.
[0030] The electronic grade solvent is propylene glycol monomethyl ether.
[0031] Embodiment 4: A method for preparing a 248nm photoresist resin comprises the following steps: synthesizing a resin to obtain a synthetic resin solution, wherein the monomers synthesized during the synthesis include the following raw materials in molar percentage: 74.95% 4-acetoxystyrene, 25% styrene, and 0.05% epoxy derivatives of styrene; removing impurities and unreacted monomers in the synthetic resin solution to obtain a No. 1 resin solution; hydrolyzing the No. 1 resin solution to obtain a No. 2 resin solution; removing metal impurities in the No. 2 resin solution to obtain a No. 3 resin solution; replacing the solvent in the No. 3 resin solution with an electronic grade solvent to obtain a No. 4 resin solution; and generating a resin solution with a tertiary amine group by adding an electronic grade secondary amine compound to the No. 4 resin solution, wherein the molar amount of the electronic grade secondary amine compound is 100% of the molar amount of the epoxy derivative of styrene.
[0032] The epoxy derivative of styrene is p-vinylbenzyl glycidyl ether.
[0033] The electronic grade secondary amine compound is morpholine.
[0034] The electronic grade solvent was diethylene glycol methyl ethyl ether.
[0035] During the resin synthesis, free radical polymerization is adopted to obtain a synthetic resin solution.
[0036] Example 5: Referring to Example 1, S1: During resin synthesis: 100 parts of monomer, 2-8 parts of initiator, and 200 parts of propylene glycol methyl ether acetate are mixed; uniformly add dropwise to a reaction bottle at 80-90°C, stop adding dropwise after 3 hours, and maintain the temperature to continue the reaction for 2 hours to synthesize the resin solution; S2: removing impurities and unreacted monomers in the synthetic resin solution: adding 600 parts of n-hexane to the synthetic resin solution, pouring out the upper layer after precipitation, adding 150 parts of ethyl acetate to the precipitate to dissolve; repeating this step 3 times to obtain a No. 1 resin solution; S3: During hydrolysis: the No. 1 resin solution was dried under vacuum at 60°C for 8 hours, 400 parts of methanol, 50 parts of water, and 0.05 parts of sodium hydroxide were added, the temperature was raised to 60-65°C, and the methanol was refluxed for 6 hours to obtain the No. 2 resin solution; S4: When removing metal impurities: precipitate the No. 2 resin solution in 400 parts of ultrapure water, pour out the upper layer of liquid, add electronic grade methanol to the precipitate to dissolve it to 200 parts; repeat this step 5 times to obtain the No. 3 resin solution; S5: When replacing the solvent: vacuum dry the No. 3 resin solution at 60°C for 48 hours, and dissolve it with an electronic grade solvent to obtain a No. 4 resin solution; the electronic grade solvent is one of propylene glycol methyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, diethylene glycol methyl ethyl ether, and cyclohexanone.
[0037] S6: Introducing tertiary amine: Adding electronic grade secondary amine compound to the No. 4 resin solution to react to generate a resin solution with tertiary amine group, the molar amount of the electronic grade secondary amine compound is 95% of the molar amount of styrene epoxy derivative, and heating to 30-60°C and reacting for 8 hours to obtain the finished product.
[0038] The initiator is one of azobisisobutyronitrile, dimethyl azobisisobutyrate and benzoyl peroxide.
[0039] The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
Claims
1. A method for preparing a 248nm photoresist resin, characterized in that: The following steps are involved: (1) synthesizing a resin to obtain a synthetic resin solution, wherein the synthesized monomers include the following raw materials in molar percentages: 50-99.99% 4-acetoxystyrene, 0-49.99% styrene, and 0.01-0.1% epoxy derivatives of styrene; (2) removing impurities and unreacted monomers from the synthetic resin solution to obtain a No. 1 resin solution; (3) hydrolyzing the No. 1 resin solution to obtain the No. 2 resin solution; (4) removing metal impurities from the No. 2 resin solution to obtain a No. 3 resin solution; (5) replacing the solvent in the No. 3 resin solution with an electronic grade solvent to obtain a No. 4 resin solution; (6) An electronic grade secondary amine compound is added to the No. 4 resin solution to generate a resin solution with a tertiary amine group, wherein the molar amount of the electronic grade secondary amine compound is 95-100% of the molar amount of the epoxy derivative of styrene.
2. The method for preparing a 248nm photoresist resin according to claim 1, characterized in that: The epoxy derivative of styrene is one of 4-glycidyl ether styrene and p-vinylbenzyl glycidyl ether.
3. The method for preparing a 248nm photoresist resin according to claim 1, characterized in that: The electronic grade secondary amine compound is one of morpholine, N-phenylethylamine and indoline.
4. The method for preparing a 248nm photoresist resin according to claim 1, characterized in that: In the step (1), the resin is synthesized by free radical polymerization to obtain a synthetic resin solution.
5. The method for preparing a 248nm photoresist resin according to claim 1, characterized in that: The electronic grade solvent is one of propylene glycol methyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, diethylene glycol methyl ethyl ether, and cyclohexanone.