The x-ray absorption spectroscopy analysis of the negative-tone PAG bound resist

Development of new EUV resists is required for next-generation EUV lithography. A resist in which a large amount of photoacid generator (PAG) is introduced into the polymer side chain has been reported as a high-resolution nonchemically amplified negative-tone resist. In this study, we synthesized a new high-PAG loading-type negative-tone resist as a model resist, evaluated EUV sensitivity by flood exposure, and also performed carbon K-edge and sulfur Ledge X-ray absorption spectroscopy (XAS) analysis. The synthesized high-PAG loading bound resist had a 79 mol% PAG unit in the polymer side chain. After the EUV exposure, the resist behaved as a negative-tone resist in the alkaline developer and a positive-tone resist in the organic developer. From the results of the XAS analysis, the possible decomposition mechanisms of the PAG unit in the polymer were estimated.