A Silicon Containing Positive Photoresist (SIPR) for a Bilayer Resist System

Abstract

A new silicon containing positive photoresist (SIPR), which has excellent durability against oxygen dry etching, was prepared and evaluated as the thin top, or resolution layer, in a bilayer resist system. SIPR, a partly trimethylsilylmethylated resorcinol‐formaldehyde resin mixed with a naphthoquinonediazide, was thinly coated onto a thick layer of polyimide resin on a silicon wafer. After exposure and development, positive patterns, including 0.7 μm lines, were obtained in this thin top layer. Those patterns were transferred into the bottom layer of polyimide either by reactive oxygen ion etching or oxygen ion beam etching with good accuracy. No residues were observed on wafers after the transfer.