Metal ion reduction in novolak resin using an ion exchange catalyst in a polar solvent and photoresists compositions therefrom

摘要

The present invention provides methods for producing water insoluble, aqueous alkali soluble, film forming novolak resins having an extremely low level of metal ions, utilizing treated anion and cation exchange resins. A method is also provided for producing photoresist composition having a very low level of metal ions from such novolak resin and for producing semiconductor devices using such photoresist compositions.