COPOLYMER FOR IMMERSION LITHOGRAPHY AND COMPOSITIONS

摘要

A copolymer capable of giving surface characteristics suitable for immersion lithography which can prevent not only pattern defects such as water mark but also sensitivity or pattern shape abnormalities caused by the dissolution of additives such as radiation-sensitive acid generator; and compositions containing the copolymer. A copolymer for immersion lithography which comprises as the essential constituents repeating units (A) capable of being deblocked by the action of an acid and thus forming alkali-soluble groups and repeating units (B) having lactone structure, characterized in that when a water droplet formed by dropping 15Vl of pure water onto a thin film made by applying a solution of the copolymer in propylene glycol monomethyl ether acetate (hereinafter often referred to as "PGMEA") to a wafer and heating the resulting coating begins to shift its position, the inclination of the wafer is 35°or below or the contact angle at the uppermost point of the water droplet is 64°or above.