SUBSTRATE PROTECTIVE FILM-FORMING COMPOSITION AND PATTERN FORMING PROCESS

• US 20200133123A1
• Filed: 10/08/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Shin-Etsu Chemical Company Limited
• Original Assignee: Shin-Etsu Chemical Company Limited
• Inventors: Kobayashi, Tomohiro, Oikawa, Kenichi, Sagehashi, Masayoshi, Adachi, Teppei
• Granted Patent: US 11,662,663 B2
• Time in Patent Office: Days
• CPC Class Codes: G03F 7/0043 Chalcogenides; Silicon, germanium, arsenic or derivatives thereof; Metals, oxides or alloys thereof G03F7/0044 takes precedence
• CPC Class Codes: G03F 7/0048 characterised by the solvents or agents facilitating spreading, e.g. tensio-active agents
• CPC Class Codes: G03F 7/038 Macromolecular compounds which are rendered insoluble or differentially wettable G03F7/075 takes precedence; macromolecular azides G03F7/012; macromolecular diazonium compounds G03F7/021
• CPC Class Codes: G03F 7/0397 the macromolecular compound having an alicyclic moiety in a side chain
• CPC Class Codes: G03F 7/092 characterised by backside coating or layers, by lubricating-slip layers or means, by oxygen barrier layers or by stripping-release layers or means
• CPC Class Codes: G03F 7/11 having cover layers or intermediate layers, e.g. subbing layers G03F7/091 - G03F7/093, B41N3/03 take precedence
• CPC Class Codes: G03F 7/325 Non-aqueous compositions

Abstract

A composition comprising (A) a polymer comprising recurring units (a1) having a carboxyl group protected with an acid labile group and recurring units (a2) having a cyclic ester, cyclic carbonate or cyclic sulfonate structure, (B) a thermal acid generator, and (C) an organic solvent is suited to form a protective film between a substrate and a resist film. Even when a metal-containing resist film is used, the protective film is effective for preventing the substrate from metal contamination.

Claims

1. A composition for forming a protective film between a substrate and a resist film, the composition comprising

(A) a polymer comprising recurring units (a1) having a carboxyl group protected with an acid labile group and recurring units (a2) having a structure selected from a cyclic ester, cyclic carbonate, and cyclic sulfonate,

(B) a thermal acid generator, and

(C) an organic solvent.

2. The composition of claim 1 wherein the recurring units (a1) have the formula (a1):

3. The composition of claim 1 wherein the recurring units (a2) have the formula (a2):

4. The composition of claim 1 wherein the polymer further comprises recurring units (a3) having a carboxyl group.

5. A pattern forming process comprising the steps of:

(i) applying the substrate protective film-forming composition of claim 1 to a substrate to form a protective film thereon,

(ii) applying a resist material on the protective film to form a resist film thereon,

(iii) exposing the resist film to high-energy radiation,

(iv) developing the exposed resist film in a developer, and

(v) dissolving away the protective film in entirety or in a selected portion using an organic solvent or basic aqueous solution.

6. The pattern forming process of claim 5 wherein the developer used in step (iv) comprises at least 60% by weight of at least one organic solvent selected from the group consisting of 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, acetophenone, 2′

-methylacetophenone, 4′

-methylacetophenone, butyl acetate, isobutyl acetate, pentyl acetate, isopentyl acetate, phenyl acetate, methyl valerate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, benzyl acetate, methyl phenylacetate, and methyl 3-phenylpropionate.

7. The pattern forming process of claim 5 wherein the resist film comprises at least 2% by weight of silicon, or one or more elements selected from the metals of the 4th, 5th and 6th periods in Periodic table.