Protective film-forming composition having acetal structure and amide structure
A composition for forming a protective film having excellent resistance to a wet etching solution for semiconductors during a lithographic process in the manufacture of semiconductors; a method of forming a resist pattern using said protective film; and a method for manufacturing a semiconductor device. This composition for forming a protective film against a wet etching solution for semiconductors includes: a compound or polymer which contains at least one among an acetal structure and an amide structure; and a solvent. The polymer is preferably a copolymer of: a compound (a) containing at least one acetal structure in a molecule; and a compound (b) containing at least one amide structure in a molecule.
1. A protective film-forming composition for forming a protective film against a semiconductor wet etchant, the composition comprising
a solvent, and
a component that is a compound or polymer containing at least one acetal structure and at least one amide structure,
wherein the at least one acetal structure comprises a structure represented by formula (1):
wherein in formula (1),
R 1 and R 2 are the same as or different from each other and are each a hydrogen atom, or a C1-C10 alkyl or C6-C40 aryl group optionally substituted with a monovalent organic group (A),
n 1 is 0, 1 or 2,
n 2 is 1 or 2,
A 1 denotes a hydrogen atom or a hydroxy group,
A 2 denotes a —CH(R 0 )-A 4 group,
R 0 denotes a hydrogen atom, a phenyl group optionally substituted with 1 to 3 hydroxy groups, or a benzodioxole group, and
A 3 and A 4 each denote an identical or different monovalent organic group (A-1).
2. The protective film-forming composition according to claim 1 , wherein the component is the polymer, and the polymer is a copolymer of a compound (a) containing the at least one acetal structure in the molecule and represented by the structure of formula (1) and a compound (b) containing the at least one amide structure in the molecule.
3. The protective film-forming composition according to claim 1 , wherein the at least one acetal structure is a structure that protects adjacent hydroxy groups in an aromatic group.
4. The protective film-forming composition according to claim 1 , wherein at least one amide structure comprises a structure represented by —CO—NH— or —CO—N═.
5. The protective film-forming composition according to claim 2 , wherein the compound (b) is represented by formula (2):
wherein in formula (2), R 20 denotes a hydrogen atom or a methyl group, and R 21 and R 22 are the same as or different from each other and are each a hydrogen atom, or a C1-C10 alkyl or C6-C40 aryl group optionally substituted with a monovalent organic group (B) and optionally interrupted by an oxygen atom or a quaternary ammonium cation).
6. The protective film-forming composition according to claim 5 , wherein the monovalent organic group (B) is selected from the group consisting of a hydroxy group, a cyano group, a sulfo group, a carboxylate group, a boron atom optionally substituted with one or two hydroxy groups, an optionally halogenated C1-C6 alkyl group, and an —NR a1 R b1 group in which R a1 and R b1 are the same as or different from each other and each denote a hydrogen atom or a C1-C3 alkyl group.
7. The protective film-forming composition according to claim 2 , wherein the compound (b) is represented by formula (2-1):
wherein in formula (2-1), R 20 denotes a hydrogen atom or a methyl group, R 23 denotes a C1-C5 alkylene group, and R 24 denotes a blocked isocyanate group).
8. The protective film-forming composition according to claim 1 , further comprising a crosslinking catalyst.
9. The protective film-forming composition according to claim 1 , further comprising a crosslinking agent.
10. The protective film-forming composition according to claim 1 , further comprising a surfactant.
11. A protective film, which is a calcined product of a coating film comprising the protective film-forming composition according to claim 1 .
12. A method for producing a resist-patterned substrate, which is used for manufacture of a semiconductor, comprising applying the protective film composition according to claim 1 onto a semiconductor substrate and calcining the composition to form a protective film as a resist underlayer film.
13. A method for manufacturing a semiconductor device, comprising
forming a protective film against a semiconductor wet etchant with the protective film-forming composition according to claim 1 on a semiconductor substrate optionally having an inorganic film formed on a surface thereof,
forming a resist pattern on the protective film,
dry-etching the protective film through the resist pattern as a mask to expose a surface of the inorganic film or of the semiconductor substrate, and
wet-etching the inorganic film or the semiconductor substrate with a semiconductor wet etchant through the dry-etched protective film as a mask, and cleaning the semiconductor substrate.