Process for making low optical polymers and copolymers for photoresists and optical applications
US5625007A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1994 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Aug 24, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F2810/50
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention pertains to polymers comprising poly(4-hydroxystyrene) or substituted poly(4-hydroxystyrene) or both. The polymers have low optical density (absorbance) over a wavelength range from about 240 to about 260 nm, as well as low optical density over the near UV and visible spectrum (310 to 800 nm). Such polymers are produced by polymerizing 4-acetoxystyrene and/or substituted 4-acetoxystyrene monomers, with or without other comonomers, and subsequently performing transesterification. In the most preferred embodiment of the present invention, the polymers are produced using at least one alcohol as a reaction medium, a chain transfer agent and a transesterification reactant, providing an unusually economic process. These polymers are particularly useful as photoresist components for use in combination with deep UV, X-ray, and E-Beam imaging systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.