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CN-122011271-A - Acrylic copolymer, preparation method and application thereof and photoresist composition

CN122011271ACN 122011271 ACN122011271 ACN 122011271ACN-122011271-A

Abstract

The invention belongs to the field of semiconductor manufacturing, and particularly provides an acrylic copolymer, a preparation method and application thereof, and a photoresist composition. The acrylic copolymer comprises a structural unit I with a structure shown in a formula 1, a structural unit II with a structure shown in a formula 2 and a structural unit III with a structure shown in a formula 3, and when the acrylic copolymer is used as an ArF photoresist resin, the photoresist has high light transmittance and high resolution at 193nm wavelength and excellent etching resistance.

Inventors

  • CHEN NINGHAI
  • HUANG SHAOJIE
  • WANG XIAOXIONG
  • LIU HEPING
  • LI LIPENG
  • JIANG YU
  • LI HEHE

Assignees

  • 福建泓光半导体材料有限公司

Dates

Publication Date
20260512
Application Date
20260204

Claims (10)

  1. 1. The acrylic copolymer is characterized by comprising a structural unit I shown in a structural formula 1, a structural unit II shown in a structural formula 2 and a structural unit III shown in a structural formula 3: wherein " "Means that the connection key is a bond, R 1 、R 2 and R 4 are each independently hydrogen or methyl, L is-O-, a single bond or an alkylene group having 1 to 4 carbon atoms, R 3 represents an acid labile group and is selected from a substituted cycloalkyl group having 7 to 15 carbon atoms, an oxygenated cycloalkyl group having 3 to 8 carbon atoms, a cycloalkyl ester group having 4 to 8 carbon atoms, and a substituent in R 3 is a methyl group; R 5 is an alkylene group having 1 to 8 carbon atoms or a cycloalkylene group having 5 to 10 carbon atoms, and n is 0 or 1.
  2. 2. The acrylic copolymer according to claim 1, wherein the molar ratio of structural unit I, structural unit II and structural unit III is c 1 /c 2 /c 3 ,c 1 of 3 to 5, c 2 of 2 to 4, c 3 of 2 to 4, and c 1 +c 2 +c 3 = 10; Preferably, the weight average molecular weight of the acrylic copolymer is 5000-20000, and the molecular weight distribution index is 1.20-2.50.
  3. 3. The acrylic copolymer according to claim 1 or 2, wherein L is-O-, methylene or ethylene; Preferably, R 3 is selected from the group consisting of: 。
  4. 4. an acrylic copolymer according to any one of claims 1 to 3, wherein R 5 is selected from methylene, ethylene, n-propylene, n-butylene, cyclopentylene, cyclohexylene or adamantylene.
  5. 5. A process for preparing the acrylic copolymer according to any one of claims 1 to 4, comprising polymerizing a comonomer in the presence of a first organic solvent and an initiator to form the acrylic copolymer, wherein the comonomer comprises a first monomer having a structure represented by formula a, a second monomer having a structure represented by formula b, and a third monomer having a structure represented by formula c: in the formulae a to c, R 1 、R 2 and R 4 are each independently hydrogen or methyl, L is-O-, a single bond or an alkylene group having 1 to 4 carbon atoms, R 3 is selected from a substituted cycloalkyl group having 7 to 15 carbon atoms, an oxacycloalkyl group having 3 to 8 carbon atoms, a cycloalkyl ester group having 4 to 8 carbon atoms, and a substituent of R 3 is methyl; R 5 is an alkylene group having 1 to 8 carbon atoms or a cycloalkylene group having 5 to 10 carbon atoms, and n is 0 or 1.
  6. 6. The method of claim 5, wherein the first monomer is present in an amount of 30% to 50%, the second monomer is present in an amount of 20% to 40%, and the third monomer is present in an amount of 20% to 40% based on the total molar amount of the comonomers.
  7. 7. The method according to claim 5 or 6, wherein the polymerization reaction is carried out at a temperature of 50-80 ℃ for a reaction time of 1-8 hours; Preferably, the initiator is one or more of azobisisobutyronitrile, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, azobisisoheptonitrile, dimethyl azobisisobutyrate, tert-butyl peroxybenzoate and dicumyl peroxide; Preferably, the mass usage amount of the initiator is 0.1% -3% of the total mass of the comonomer; Preferably, the first organic solvent is selected from one or more of tetrahydrofuran, propylene glycol methyl ether acetate, propylene glycol methyl ether, cyclohexanone, ethyl lactate, N-dimethylformamide and N-methylpyrrolidone.
  8. 8. Use of the acrylic copolymer according to any one of claims 1 to 4 for the preparation of photoresists.
  9. 9. A photoresist composition comprising an ArF photoresist resin and a second organic solvent, wherein the ArF photoresist resin is the acrylic copolymer of any one of claims 1 to 4.
  10. 10. The photoresist composition of claim 9, wherein the photoresist composition further comprises a photoacid generator; Preferably, based on the total weight of the photoresist composition, the mass content of the ArF photoresist resin is 6% -20%, the mass content of the photoacid generator is 0.1% -2%, and the mass content of the second organic solvent is 78% -93%.

Description

Acrylic copolymer, preparation method and application thereof and photoresist composition Technical Field The invention belongs to the field of semiconductor manufacturing, and particularly relates to an acrylic copolymer, a preparation method and application thereof, and a photoresist composition. Background The continued advancement of semiconductor fabrication technology is pushing the scaling of integrated circuit feature sizes, process nodes into the 7nm, 5nm and more advanced stages. In the process, as a key link of pattern transfer, the requirements on precision and resolution are increasingly stringent. ArF lithography based on 193nm wavelength has become an indispensable patterning tool in advanced processes because of the higher pattern resolution achieved by shorter exposure wavelength. Photoresists are the core materials of the lithographic process, whose properties directly determine the accuracy of the pattern transfer and the final characteristics of the device. Photoresists typically comprise a resin matrix, photosensitive components, solvents, and the like. Among them, photoresist resins are generally polymers having specific functions formed by polymerization of one or more monomers. As a film-forming material, the resin forms the backbone of the photoresist, and its molecular structure directly determines the mechanical properties, optical properties, thermal stability and chemical resistance of the photoresist. Therefore, the design and synthesis of photoresist resins is central to the development of photoresist technology. In ArF lithography, the photoresist resin needs to have high light transmittance at 193nm wavelength, high resolution, good film forming property, and excellent etching resistance. The performances together ensure that the photoresist can realize high-fidelity pattern transfer in the steps of exposure, development, subsequent etching and the like. In the conventional KrF lithography (248 nm), a poly-p-hydroxystyrene (PHS) type resin is commonly used, whose benzene ring structure provides good etching resistance, but the structure has strong absorption at 193nm wavelength, resulting in a significant decrease in light transmittance. For this reason, the ArF photoresist system proposed in the related art is a resin based on an alicyclic polymer, and a certain mechanical strength and etching resistance are obtained while maintaining a high light transmittance by introducing alicyclic structural units such as a norbornyl group, an adamantyl group, and the like. However, with the development of integrated circuit processes towards higher aspect ratio and finer patterns, particularly in the application scenarios of nanoscale pattern preparation and advanced plasma etching processes, the molecular architecture of the existing alicyclic resin system faces a significant bottleneck in terms of collaborative optimization of etching resistance, resolution and light transmittance, and it is difficult to further improve etching durability while maintaining high light transmittance and high resolution, which severely restricts the fidelity of pattern transfer and the expansion space of process windows. Therefore, there is a need to develop new photoresist resin systems to better meet the continuous scaling process requirements. Disclosure of Invention The invention aims to provide an acrylic copolymer, a preparation method and application thereof and a photoresist composition. When the acrylic copolymer is used as ArF photoresist resin, the photoresist has high light transmittance and high resolution at 193nm wavelength and excellent etching resistance. The first aspect of the present invention provides an acrylic copolymer comprising a structural unit I having a structure shown in formula 1, a structural unit II having a structure shown in formula 2, and a structural unit III having a structure shown in formula 3: wherein " "Represents a bond, R 1、R2 and R 4 are each independently hydrogen or methyl, L is-O-, a single bond or an alkylene group having 1 to 4 carbon atoms, R 3 is selected from a substituted cycloalkyl group having 7 to 15 carbon atoms, an oxacycloalkyl group having 3 to 8 carbon atoms, a cycloalkyl ester group having 4 to 8 carbon atoms, and the substituent in R 3 is methyl, R 5 is an alkylene group having 1 to 8 carbon atoms or a cycloalkylene group having 5 to 10 carbon atoms, and n is 0 or 1. In some embodiments of the invention, the molar ratio of structural unit I, structural unit II and structural unit III is 3-5 for c 1/c2/c3,c1, 2-4 for c 2, 2-4 for c 3, and c 1+c2+c3 =10. In some embodiments of the present invention, the weight average molecular weight of the acrylic copolymer is 5000-20000, and the molecular weight distribution index is 1.20-2.50. In some embodiments of the invention, L is-O-, methylene, or ethylene. In some embodiments of the invention, R 3 is selected from any one of the following groups: In some embodiments of the invention, R 5 is select