Polymers, positive resist compositions and patterning process

Abstract

A polymer is composed of recurring units of hydroxyvinylnaphthalene, (meth)acrylic units having a lactone ring fused to a bridged ring, and (meth)acrylic units having acid labile groups. A positive resist composition comprising the polymer as a base resin, when exposed to high-energy radiation and developed, exhibits a high sensitivity, a high resolution, and a minimal line edge roughness due to controlled swell during development.

Description

Claims

1. A polymer comprising recurring units of the general formulae (1a) and (1b):

2. The polymer of claim 1, further comprising recurring units of the general formula (1c):

3. A positive resist composition comprising the polymer of claim 1 as a base resin.

4. The positive resist composition of claim 3, further comprising an organic solvent and a photoacid generator, and serving as a chemically amplified resist composition.

5. The positive resist composition of claim 3, further comprising a dissolution inhibitor.

6. The positive resist composition of claim 3, further comprising a basic compound and/or a surfactant.

7. A process for forming a pattern comprising the steps of applying the resist composition of claim 3 onto a substrate, heat treating, exposing to high-energy radiation, and developing with a developer.

8. The pattern forming process of claim 7 wherein the high-energy radiation has a wavelength of 180 to 200 nm.