| 摘要 |
PURPOSE: Provided is a process for preparing a polymer useful as a base resin in a positive resist material which shows high sensitivity, high resolution, exposure latitude and process adaptability, a satisfactory pattern profile after exposure and minimized edge roughness. CONSTITUTION: The process for preparing a polymer containing repeating units of the formula 2, comprises subjecting a polymer containing repeating units of the formula 1 to selective deprotection of acetal groups by using an acid catalyst. In the formulae 1 and 2, R2 and R3 are a straight or branched C1-C10-alkyl group, or R2 and R3, taken together with the carbon and oxygen atoms to which they are attached, may form a ring, R5 is hydrogen atom, hydroxy group, a straight or branched alkyl group, an alkoxy group which may be substituted, halogen atom or an acid labile group, R1, R4 and R6 are hydrogen atom or methyl group, R7 is a C4-C20-t-alkyl group, n is an integer of 0 to 4, p and r are positive integers, and q is 0 or a positive integer. The chemically-amplified positive resist material comprises the polymer together with an organic solvent, an acid generator and optionally a dissolution inhibitor.
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