A new family of non-chemically amplified resists

Abstract

Non-chemically amplified resists offer advantages over chemically-amplified (CA) resists because they are less susceptible to temperature variations and contaminants. In order for non-CA resists to be viable, they have to perform lithographically at an equivalent level with the CA resists from the points of view of quantum yield, resolution, and etch resistance. We report here on new non-CA resists based on polymer esters that undergo deesterification to the corresponding acids upon exposure to UV, x-ray and e-beam radiation. The efficiency of the radiation reaction is surprisingly high. The resulting poly acids are base soluble and can be employed as positive working resists. The resists are composed of polymers and copolymers of methacrylate esters. The sensitivity of one derivative to x-ray is 75 mJ/cm2 and to e-beam is 1.0 μC/cm2 at 10 KV. Best resolution obtained was 125 nm with x-ray radiation.