Carboxylic acid derivatives and their synthesis method

摘要

This invention relates to novel carboxylic acid derivatives represented by the following formula I and their synthesis: <CHEM> wherein, R1 is an hydrogen atom, an alkyl group or an alkoxy group of 1 to 20 carbon atoms in a linear, branched or cyclic form; R2 is a carboxy group of 1 to 40 carbon atoms in a linear, branched or cyclic form which is unsubstituted, or substituted into a hydroxy group, an ester group and an ether group. The novel carboxylic acid derivatives are more easily decomposed by acid than t-butyl ester compounds but are not dissolved in basic aqueous solution. According to this invention, carboxylic acid is under condensation with halogen compounds designed to prepare a larger monomolecular compound compared to the conventional method. Further, the condensed site is easily decomposed by acid but is extremely insoluble by basic aqueous solution. The carboxylic acid derivatives in a photoresist composition function not only as a dissolution promoter in the exposed area due to formation of the carboxylic aicd, thus enhancement of etching resistance and pattern profile in a resist.