Wide process window photoresist adaptive to multiple exposure and preparation method and application thereof
By using film-forming resin and dynamic crosslinking technology under acidic conditions in photoresist, the problem of insufficient lithography accuracy and etch resistance in multiple exposure processes is solved, and a wider process window and better lithography performance are achieved.
Patent Information
- Application Number
- CN202510259381.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-05-30
AI Technical Summary
It is difficult for existing photoresist to maintain good photolithography accuracy and etch resistance in multiple exposure processes, and the process window is narrow, making it difficult to adapt to different lithography conditions.
The film-forming resin is prepared through boron esterification reaction and double bond addition reaction using a formula including film-forming resin, photoacid generator, acid diffusion inhibitor and photoresist solvent, and the performance of the photoresist is optimized through dynamic cross-linking and secondary cross-linking technology under acidic conditions.
The good photolithography accuracy and etch resistance of photoresist in multiple exposure processes are achieved, the process window is expanded, and different lithography conditions are adapted to different lithography conditions.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of photoresist preparation, and particularly relates to a wide process window photoresist adapted to multiple exposures, a preparation method thereof, and an application thereof. Background Art
[0002] A photoresist is a light-sensitive liquid mixture material. Its core function is to transfer the fine patterns on the mask plate to the surface of the substrate through a photochemical reaction, and it is a key material in the manufacturing of semiconductor chips, display panels, and PCBs. A photoresist usually consists of a film-forming resin, a photoinitiator (such as a photoacid generator), a solvent, and other additives. Its working principle is similar to that of a photographic negative: during the exposure process, the photoinitiator absorbs the light energy of a specific wavelength, triggering a chemical structure change (such as crosslinking or decomposition) of the resin, thereby changing the solubility of the photoresist in the developer, and finally forming a micro-nano scale pattern corresponding to the mask plate. According to the development characteristics, photoresists can be divided into positive resists and negative resists. For positive resists, the exposed areas are dissolved in the developer to form the same pattern as the mask; for negative resists, the unexposed areas are dissolved to form a complementary pattern.
[0003] According to the different lithography precisions and light source wavelengths, photoresists can be divided into g-line photoresists, i-line photoresists, KrF photoresists, ArF photoresists, and EUV photoresists. Among them, the light source wavelength of KrF photoresists is 248 nm, which belongs to deep ultraviolet photoresists and is mainly used for the production of 8-inch wafers; due to its high lithography precision and certain process latitude, this photoresist has been widely used.
[0004] How to design and develop supporting materials (film-forming resins) that meet the requirements of photoresist formulations is the focus of current photoresist product formulation development. How to make the entire photoresist formulation have good resolution and line roughness has always been a key research direction in the industry. Summary of the Invention
[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a wide process window photoresist adapted to multiple exposures, a preparation method thereof, and an application thereof.
[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A wide process window photoresist adapted to multiple exposures, comprising a film-forming resin, a photoacid generator, an acid diffusion inhibitor, and a photoresist solvent.
[0007] Among them, the preparation method of the film-forming resin is as follows: S1. Add 4-biphenylboronic acid to an organic solvent, stir and dissolve it, then add 2-butene-1,4-diol and a catalyst thereto, and carry out a reflux reaction under a nitrogen atmosphere. After the reaction is completed, precipitate and dry to obtain a solid product; S2. Add 4-aminostyrene, the solid product, tert-butyl acrylate, and a vinyl silane coupling agent into an organic solvent, mix them evenly to obtain a mixed solution, cool it down to 0 - 5°C, and then, under a nitrogen atmosphere, add an initiator to the mixed solution, heat and stir for reaction. After the reaction is completed, carry out precipitation and drying to obtain a film-forming resin.
[0008] In the technical solution disclosed by the present invention, in step S1, the mass ratio of 4-biphenylboronic acid, 2-butene-1,4-diol, and the catalyst is 10 - 15:3 - 6:1 - 1.5. For example, 10:3:1, 10:4:1.5, 10:6:1.5, 12:6:1.5, 15:3:1, 15:4:1.2, 15:6:1.5 can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.
[0009] Specifically, in step S1, the catalyst is selected from triethylamine.
[0010] In the technical solution disclosed by the present invention, in step S1, the temperature of the reflux reaction is 60 - 80°C. For example, 60°C, 65°C, 70°C, 75°C, 80°C can be selected; the time of the reflux reaction is 8 - 16 h. For example, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.
[0011] In the technical solution disclosed by the present invention, in step S2, the mass ratio of 4-aminostyrene, the solid product, tert-butyl acrylate, the vinyl silane coupling agent, and the initiator is 10 - 15:5 - 10:3 - 5:1 - 2:1 - 2.
[0012] Specifically, the vinyl silane coupling agent is selected from vinyltriethoxysilane or vinyltrimethoxysilane.
[0013] Specifically, the initiator is selected from benzoyl peroxide or azobisisobutyronitrile.
[0014] In the technical solution disclosed by the present invention, in step S2, the temperature of the heating and stirring reaction is 70 - 90°C. For example, 70°C, 75°C, 80°C, 85°C, 90°C can be selected; the time of the heating and stirring reaction is 12 - 24 h. For example, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h can be selected; but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.
[0015] In the technical solution disclosed by the present invention, the mass ratio of the film-forming resin, the photoacid generator, the acid diffusion inhibitor, and the photoresist solvent is 100:3 - 6:1 - 2:400 - 800.
[0016] Specifically, the photoacid generator is selected from triphenylsulfonium salts.
[0017] Specifically, the acid diffusion inhibitor is selected from ethanolamine, diethanolamine, triethanolamine or trihexylamine.
[0018] Specifically, the photoresist solvent is selected from propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, neopentyl acetate or ethyl lactate.
[0019] The present invention provides a method for preparing the above-mentioned wide process window photoresist adapted to multiple exposures, comprising the following steps: adding a film-forming resin, a photoacid generator, and an acid diffusion inhibitor into a photoresist solvent according to a formulation ratio, shaking in the dark to dissolve them sufficiently, and then filtering to obtain the wide process window photoresist adapted to multiple exposures.
[0020] The present invention also provides an application of the above-mentioned wide process window photoresist in a multiple exposure lithography process.
[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) First, under the action of a catalyst, the present invention performs a borylation reaction on 4-biphenylboronic acid and 2-butene-1,4-diol to obtain a benzene borate compound containing double bonds. Subsequently, through an addition reaction between the double bonds, a film-forming resin is obtained. Then, the film-forming resin, a photoacid generator, and an acid diffusion inhibitor are added into a photoresist solvent to obtain a photoresist. The photoresist prepared by the present invention exhibits good lithography accuracy and etching resistance.
[0022] (2) For the benzene borate compound containing double bonds prepared by the present invention, under acidic conditions, the borate bond will undergo partial hydrolysis to release free benzene boronic acid groups. The benzene boronic acid groups form dynamic crosslinks with -NH in 4-aminostyrene through B-N coordination bonds. After the first exposure of the photoresist provided by the present invention, it is treated with an acidic solution (pH = 2-3) to achieve secondary crosslinking, adapting to the multiple exposure process. By compensating for the difference in developer penetration through local crosslinking, the sidewall roughness is reduced, and the lithography accuracy is significantly improved. 2 Through B-N coordination bonds to form dynamic crosslinks, after the first exposure of the photoresist provided by the present invention, it is treated with an acidic solution (pH = 2-3) to achieve secondary crosslinking, adapting to the multiple exposure process. By compensating for the difference in developer penetration through local crosslinking, the sidewall roughness is reduced, and the lithography accuracy is significantly improved.
[0023] (3) The vinyl silane coupling agent provided by the present invention can undergo a crosslinking reaction with other raw materials to form a denser network structure. This dense crosslinked structure can effectively block the penetration of the etchant, thereby improving the etching resistance of the photoresist; at the same time, it can also enhance the adhesion between the photoresist and the substrate, contributing to improving the stability of the photoresist during the etching process and reducing the problem of decreased etching resistance caused by poor adhesion. Specific embodiments
[0024] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.
[0025] It should be noted that unless otherwise specified, the chemical reagents involved in the present invention are all purchased through commercial channels. Example 1
[0026] A preparation method of a wide process window photoresist adapted to multiple exposures includes the following steps: Add 100 parts of film-forming resin, 3 parts of photoacid generator triphenylsulfonium chloride, and 1 part of acid diffusion inhibitor diethanolamine to 400 parts of photoresist solvent propylene glycol monomethyl ether acetate, shake in the dark to dissolve it fully, and then filter to obtain the wide process window photoresist adapted to multiple exposures; Among them, the preparation method of the film-forming resin is as follows: S1. Add 10 g of 4-biphenylboronic acid to 150 mL of organic solvent DMF, stir to dissolve, then add 3 g of 2-butene-1,4-diol and 1 g of catalyst triethylamine thereto, carry out a reflux reaction under a nitrogen atmosphere, the temperature of the reflux reaction is 60 °C, the time of the reflux reaction is 16 h, after the reaction is completed, drop the reaction solution into deionized water for precipitation, and dry to obtain a solid product; S2. Add 10 g of 4-aminostyrene, 5 g of the solid product, 3 g of tert-butyl acrylate, and 1 g of vinyltriethoxysilane to 150 mL of organic solvent DMF, mix evenly to obtain a mixed solution, cool down to 0 °C, then under a nitrogen atmosphere, add 1 g of initiator azobisisobutyronitrile to the mixed solution, heat and stir the reaction at 70 °C for 24 h, after the reaction is completed, drop the reaction solution into deionized water for precipitation, and dry to obtain the film-forming resin. Example 2
[0027] A preparation method of a wide process window photoresist adapted to multiple exposures includes the following steps: Add 100 parts of film-forming resin, 4 parts of photoacid generator triphenylsulfonium chloride, and 2 parts of acid diffusion inhibitor diethanolamine to 600 parts of photoresist solvent propylene glycol monomethyl ether acetate, shake in the dark to dissolve it fully, and then filter to obtain the wide process window photoresist adapted to multiple exposures; Among them, the preparation method of the film-forming resin is as follows: S1. Add 15 g of 4-biphenylboronic acid to 150 mL of organic solvent DMF, stir to dissolve, then add 6 g of 2-butene-1,4-diol and 1.5 g of catalyst triethylamine thereto, carry out a reflux reaction under a nitrogen atmosphere, the temperature of the reflux reaction is 80 °C, the time of the reflux reaction is 8 h, after the reaction is completed, drop the reaction solution into deionized water for precipitation, and dry to obtain a solid product; S2. Add 12 g of 4-aminostyrene, 8 g of the solid product, 4 g of tert-butyl acrylate, and 1.5 g of vinyltriethoxysilane to 150 mL of the organic solvent DMF, mix well to obtain a mixed solution, cool it down to 0 °C, and then, under a nitrogen atmosphere, add 1.5 g of the initiator azobisisobutyronitrile to the mixed solution. Stir and react by heating at 90 °C for 12 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation, and then dry it to obtain the film-forming resin. Example 3
[0028] A preparation method of a wide process window photoresist adapted to multiple exposures includes the following steps: Add 100 parts of the film-forming resin, 6 parts of the photoacid generator triphenylsulfonium chloride, and 2 parts of the acid diffusion inhibitor trihexylamine to 600 parts of the photoresist solvent dipropylene glycol methyl ether, shake it in the dark to dissolve it thoroughly, and then filter it to obtain the wide process window photoresist adapted to multiple exposures; Among them, the preparation method of the film-forming resin is as follows: S1. Add 12 g of 4-biphenylboronic acid to 150 mL of the organic solvent DMF, stir to dissolve it, and then add 4 g of 2-butene-1,4-diol and 1.2 g of the catalyst triethylamine thereto. Carry out a reflux reaction under a nitrogen atmosphere. The temperature of the reflux reaction is 70 °C, and the time of the reflux reaction is 12 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation, and then dry it to obtain the solid product; S2. Add 15 g of 4-aminostyrene, 10 g of the solid product, 5 g of tert-butyl acrylate, and 2 g of vinyltriethoxysilane to 150 mL of the organic solvent DMF, mix well to obtain a mixed solution, cool it down to 0 °C, and then, under a nitrogen atmosphere, add 2 g of the initiator azobisisobutyronitrile to the mixed solution. Stir and react by heating at 80 °C for 18 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation, and then dry it to obtain the film-forming resin. Example 4
[0029] A preparation method of a wide process window photoresist adapted to multiple exposures includes the following steps: Add 100 parts of the film-forming resin, 6 parts of the photoacid generator triphenylsulfonium p-toluenesulfonate, and 2 parts of the acid diffusion inhibitor trihexylamine to 800 parts of the photoresist solvent dipropylene glycol methyl ether, shake it in the dark to dissolve it thoroughly, and then filter it to obtain the wide process window photoresist adapted to multiple exposures; Among them, the preparation method of the film-forming resin is as follows: S1. Add 10 g of 4-biphenylboronic acid to 150 mL of the organic solvent DMF, stir to dissolve, then add 4 g of 2-butene-1,4-diol and 1 g of the catalyst triethylamine thereto, and carry out a reflux reaction under a nitrogen atmosphere. The temperature of the reflux reaction is 70 °C, and the time of the reflux reaction is 12 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation and drying to obtain a solid product; S2. Add 12 g of 4-aminostyrene, 6 g of the solid product, 3 g of tert-butyl acrylate, and 1.5 g of vinyltriethoxysilane to 150 mL of the organic solvent DMF, mix evenly to obtain a mixed solution, cool down to 0 °C, and then, under a nitrogen atmosphere, add 1.5 g of the initiator azobisisobutyronitrile to the mixed solution, and carry out a heating and stirring reaction at 80 °C for 18 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation and drying to obtain a film-forming resin. Comparative Example 1
[0030] A preparation method of a wide process window photoresist adapted to multiple exposures includes the following steps: Add 100 parts of the film-forming resin, 3 parts of the photoacid generator triphenylsulfonium chloride, and 1 part of the acid diffusion inhibitor diethanolamine to 400 parts of the photoresist solvent propylene glycol monomethyl ether acetate, shake in the dark to dissolve it fully, and then filter to obtain the wide process window photoresist adapted to multiple exposures; Among them, the preparation method of the film-forming resin is as follows: Add 10 g of 4-aminostyrene, 3 g of tert-butyl acrylate, and 1 g of vinyltriethoxysilane to 150 mL of the organic solvent DMF, mix evenly to obtain a mixed solution, cool down to 0 °C, and then, under a nitrogen atmosphere, add 1 g of the initiator azobisisobutyronitrile to the mixed solution, and carry out a heating and stirring reaction at 70 °C for 24 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation and drying to obtain a film-forming resin.
[0031] Compared with Example 1, the raw materials of the film-forming resin in Comparative Example 1 do not contain phenyl borate compounds. Comparative Example 2
[0032] A preparation method of a wide process window photoresist adapted to multiple exposures includes the following steps: Add 100 parts of the film-forming resin, 3 parts of the photoacid generator triphenylsulfonium chloride, and 1 part of the acid diffusion inhibitor diethanolamine to 400 parts of the photoresist solvent propylene glycol monomethyl ether acetate, shake in the dark to dissolve it fully, and then filter to obtain the wide process window photoresist adapted to multiple exposures; Among them, the preparation method of the film-forming resin is as follows: S1. Add 10 g of 4-biphenylboronic acid to 150 mL of the organic solvent DMF, stir to dissolve, then add 3 g of 2-butene-1,4-diol and 1 g of the catalyst triethylamine thereto, and carry out a reflux reaction under a nitrogen atmosphere. The temperature of the reflux reaction is 60 °C, and the time of the reflux reaction is 16 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation, and dry to obtain a solid product; S2. Add 10 g of 4-aminostyrene, 5 g of the solid product, and 3 g of tert-butyl acrylate to 150 mL of the organic solvent DMF, mix evenly to obtain a mixed solution, cool down to 0 °C, and then, under a nitrogen atmosphere, add 1 g of the initiator azobisisobutyronitrile to the mixed solution, and heat and stir the reaction at 70 °C for 24 h. After the reaction is completed, drop the reaction solution into deionized water for precipitation, and dry to obtain a film-forming resin.
[0033] Compared with Example 1, vinyltriethoxysilane was not added to the raw materials of the film-forming resin in Comparative Example 2.
[0034] Spin-coat the photoresists prepared in Examples 1-4 and Comparative Examples 1-2 on a polished silicon wafer, and obtain a photoresist layer with a thickness of 200 nm through baking at 90 °C / 120 s, and perform exposure using a 193 nm (ArF) lithography machine, and the exposure dose is 40 mJ / cm 2 , after the exposure is completed, treat with a hydrochloric acid solution with a pH of 2, bake on a hot stage at 120 °C / 60 s, and then perform a second exposure, and the second exposure dose is 40 mJ / cm 2 , after the exposure is completed, bake on a hot stage at 90 °C / 60 s, and develop using an alkaline aqueous developer (2.38 wt% aqueous solution of tetramethylammonium hydroxide) to obtain a preset pattern.
[0035] Photolithography accuracy test: Observe and measure the photolithography pattern using a scanning electron microscope (SEM) to obtain the minimum line width that the photolithography pattern can separate; the narrower the line width, the higher the photolithography accuracy.
[0036] Etch resistance test: Place each polished silicon wafer coated with a film on an etching machine and etch under the condition of 40CF4 / 240Ar / 60O2 for 30 s, calculate the etching rate from the film thickness before and after etching and the etching time, and the smaller the etching rate, the better the etch resistance.
[0037] The test results are shown in Table 1: Table 1 Performance test results of the photoresists prepared in Examples 1-4 and Comparative Examples 1-2
[0038] As can be seen from Table 1, the photoresists prepared in the examples of the present invention have good photolithography accuracy and etch resistance.
[0039] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, based on the present invention, some modifications and improvements can be made to it. Therefore, any modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection required by the present invention.
Claims
1. A photoresist with a wide process window suitable for multiple exposures, comprising a film-forming resin, a photoacid generator, an acid diffusion inhibitor and a photoresist solvent, characterized in that: The preparation method of the film-forming resin is as follows: S1, adding 4-biphenylboric acid to an organic solvent, stirring to dissolve, then adding 2-butene-1,4-diol and a catalyst thereto, and performing reflux reaction under a nitrogen atmosphere. After the reaction is completed, precipitating and drying to obtain a solid product; S2. Add 4-aminostyrene, solid product, tert-butyl acrylate and vinyl silane coupling agent into an organic solvent, mix well to obtain a mixed solution, cool to 0-5°C, then add an initiator to the mixed solution under a nitrogen atmosphere, heat and stir to react, and after the reaction is completed, precipitate and dry to obtain a film-forming resin.
2. The wide process window photoresist adapted for multiple exposures according to claim 1, characterized in that: In step S1, the mass ratio of 4-biphenylboric acid, 2-butene-1,4-diol and catalyst is 10-15:3-6:1-1.5, and the catalyst is selected from triethylamine.
3. The photoresist with a wide process window adapted for multiple exposures according to claim 1, characterized in that: In step S1, the temperature of the reflux reaction is 60-80° C., and the time of the reflux reaction is 8-16 h.
4. The photoresist with a wide process window adapted for multiple exposures according to claim 1, characterized in that: In step S2, the mass ratio of 4-aminostyrene, solid product, tert-butyl acrylate, vinyl silane coupling agent and initiator is 10-15:5-10:3-5:1-2:1-2, and the initiator is selected from benzoyl peroxide or azobisisobutyronitrile.
5. The photoresist with a wide process window adapted for multiple exposures according to claim 1, characterized in that: In step S2, the temperature of the heating and stirring reaction is 70-90° C., and the time of the heating and stirring reaction is 12-24 hours.
6. The photoresist with a wide process window adapted for multiple exposures according to claim 1, characterized in that The mass ratio of the film-forming resin, the photoacid generator, the acid diffusion inhibitor and the photoresist solvent is 100:3-6:1-2:400-800.
7. The photoresist with a wide process window adapted for multiple exposures according to claim 1, characterized in that: The acid diffusion inhibitor is selected from ethanolamine, diethanolamine, triethanolamine or trihexylamine.
8. The photoresist with a wide process window adapted for multiple exposures according to claim 1, characterized in that: The photoresist solvent is selected from propylene glycol methyl ether acetate, dipropylene glycol methyl ether, neopentyl acetate or ethyl lactate.
9. The method for preparing a photoresist with a wide process window suitable for multiple exposures according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: adding film-forming resin, photoacid generator and acid diffusion inhibitor into photoresist solvent according to the formula ratio, shaking in the dark to make them fully dissolved, and then filtering to obtain a photoresist with a wide process window suitable for multiple exposures.
10. Use of the wide process window photoresist as claimed in claim 9 in a multiple exposure lithography process.