Protective film forming composition having an acetal structure
A protective film-forming composition which protects against a semiconductor wet etching solution, contains a solvent and a compound or polymer thereof containing at least one acetal structure in a molecule thereof, and forms a protective film exhibiting excellent resistance against a semiconductor wet etching solution during the lithographic process when producing semiconductors; a method for producing a resist pattern-equipped substrate which uses the protective film; and a method for producing a semiconductor device.
1. A composition for forming a protective film against a wet etching liquid for semiconductor, the protective film forming composition comprising a solvent and a compound containing in the molecule thereof at least one acetal structure that protects adjacent hydroxy groups in the molecule, or a polymer thereof.
2. The protective film forming composition according to claim 1 , wherein adjacent hydroxy groups are in an aromatic group of the molecule.
3. The protective film forming composition according to claim 1 , wherein the compound has a partial structure represented by the following formula (1):
wherein:
each of R 1 and R 2 represents a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms, each of the group optionally being substituted,
n 1 is 0, 1, or 2,
n 2 is 1 or 2,
A 1 represents a hydrogen atom or a hydroxy group,
A 2 represents a —CH(R 0 )-A 4 group,
R 0 represents a hydrogen atom, a phenyl group optionally substituted with 1 to 3 hydroxy groups, or a benzodioxole group, and
A 3 and A 4 are the same or different and each represents a monovalent organic group.
4. The protective film forming composition according to claim 3 , wherein, in formula (1), n 1 is 0, and n 2 is 1.
5. The protective film forming composition according to claim 3 , wherein, in formula (1), R 1 and R 2 are the same or different and a hydrogen atom or a methyl group.
6. The protective film forming composition according to claim 3 , wherein, in formula (1), R 1 and R 2 are a hydrogen atom.
7. The protective film forming composition according to claim 1 , further comprising a crosslinking catalyst.
8. The protective film forming composition according to claim 1 , further comprising a crosslinking agent.
9. The protective film forming composition according to claim 1 , further comprising a surfactant.
10. A protective film which is a baked product of an applied film of the protective film forming composition according to claim 1 .
11. A method for producing a substrate having a resist pattern, comprising the steps of applying the protective film forming composition according to claim 1 onto a semiconductor substrate and baking the applied composition to form a protective film as a resist underlying film, which is used for producing a semiconductor.
12. A method for producing a semiconductor device, comprising the steps of:
forming a protective film on a semiconductor substrate optionally having an inorganic film formed on the surface thereof using the composition according to claim 1 for forming a protective film against a wet etching liquid for semiconductor;
forming a resist pattern on the protective film;
subjecting the protective film to dry etching using the formed resist pattern as a mask so as to expose a surface of the inorganic film or the semiconductor substrate; and using the dry-etched protective film as a mask, subjecting the inorganic film or the semiconductor substrate to wet etching with a wet etching liquid for semiconductor and to washing.