Process study of a 200 nm laser pattern generator

Abstract

An overview of resist and process development for use as the next laser pattern generation tool, which will use an approximately 200 nm laser, is presented. Some mask specific issues must be overcome if a 200 nm laser pattern generator is to be used rather than relatively well-known 193 nm wafer process. Post coating and post exposure delay are the main issues that should be taken care of before using a 200 nm laser pattern generator. The limits and possible uses of a 200 nm laser pattern generator are discussed. Among the possible 200 nm light sources, a 198 nm continuous wave laser was recently chosen as the light source. This wavelength is a little bit larger than 193 urn, so some resolution might be lost in terms of aerial image, but the transmittance at 198 nm is larger than that at 193 run. This allows for a larger side wall angle and a larger process latitude in the resist process. Overall, the target resolution of a 70 nm node can be easily obtained with a 200 nm laser pattern generator.