Synthesis and Property of Tannic Acid Derivatives and Their Application for Extreme Ultraviolet Lithography System

We synthesized tannic acid derivatives with pendant cyclohexyl acetal moieties (TA-CVEn), butyl acetal moieties (TA-BVEn), and adamantyl ester moieties (TA-ADn) by the reaction of tannnic acid (TA) with cyclohexyl vinyl ether (CVE), butyl vinyl ether (BVE), and adamantyl bromo acetate (AD) in various feeds ratios. The synthesized TA-CVEn, TA-BVEn, and TA-ADn had good solubility, good film-forming ability, and high thermal stability relevant to application of photolithography materials. However, only TA-BVE97 and TA-AD74 can be used as positive-type photo-resist materials using 2.38 wt% TMAH aq. as developer due to the result of thickness loss property. Furthermore, their resist-sensitivity upon EUV exposure tool and etching durability were adequate and they have high potential as next-generation resist material for EUV lithography.