Extreme Ultraviolet Resist Outgassing Quantification Verification by Resist Film Analysis

Abstract

Numerous investigations on extreme ultraviolet (EUV) resist outgassing have been performed using the pressure rise and gas chromatography mass spectrometry (GC–MS) method. However, the reliability of the results obtained with these methods has not been clearly discussed. In this paper, to analyze and verify the reliability of the resist outgassing results, de-protection reaction and photo acid generator's (PAG's) decomposing reaction in the resist film, which are viewed as the main source of resist outgassing, are investigated using the Fourier transform infrared spectroscopy (FT-IR). Analysis was performed on a resist film after EUV exposure, before post exposure bake (PEB). Based on the measured amount of de-protection reaction in the resist film, the amounts of resist outgassing released were calculated. It was found that the resist outgassing amount obtained through FT-IR was somewhere between those obtained using the pressure rise and GC–MS methods results. These similarities in the results substantiate the reliability of resist outgassing amounts obtained through these analysis methods.