Design of photoresists with reduced environmental impact. II. Water-soluble resists based on photocrosslinking of poly(2-isopropenyl-2-oxazoline)
✍ Scribed by J. M. Havard; M. Yoshida; D. Pasini; N. Vladimirov; J. M. J. Frechet; D. R. Medeiros; K. Patterson; S. Yamada; C. G. Willson; J. D. Byers
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 353 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
The performance of water-and solvent-cast, two-component photoresist films containing poly(2-isopropenyl-2-oxazoline) or poly(2-isopropenyl-2-oxazoline-costyrene) with a photoacid generator has been investigated. These materials afford negative-tone images after deep-UV exposure and development in a suitable medium (water or toluene). Resist solutions prepared from polymers containing at least 80 mol % 2-isopropenyl-2-oxazoline may be cast from and developed in pure water. Features of higher quality can be obtained when the resist is cast from 2-methoxyethanol, probably because side reactions such as partial hydrolysis of the pendant oxazoline rings in aqueous environments are avoided. It was possible to resolve micrometer scale patterns using ca. 200 mJ/cm 2 of irradiation at 254 nm, followed by heating 2 min at 130°C and development in water alone. Image quality and etch resistance were improved using copolymers containing up to 20 mol % of styrene repeat units.