WATER CASTABLE - WATER STRIPPABLE TOP COATS FOR 193 NM IMMERSION LITHOGRAPHY

摘要

A topcoat material for applying on top of a photoresist material is disclosed. The topcoat material comprises a polymer which is sparingly soluble or insoluble in water at a temperature of 25°C or below but soluble in water at a temperature of 60° C or above. The polymer contains polyvinyl alcohol monomer unit and a polyvinyl acetate or poly.vinyl ether monomer unit having the following polymer structure: wherein R is an aliphatic or alicyclic radical; m and n are independently integers, and are the same or different; and p is zero or 1. The topcoat material may be used m lithography processes, therein the topcoat material is applied on a photoresist layer. The topcoat material is particularly useful in immersion lithography techniques using water as the imaging medium. The topcoat material of the present invention are also useful for immersion lithography employing organic liquid as immersion medium.