Novel negative-tone molecular resist based on polyphenol derivative for extreme ultraviolet lithography

This study investigated the extreme ultraviolet (EUV) lithographic performance of negative-tone molecular resists based on 2,7-bis[bis(2,3,5-trimethyl-4-hydroxyphenyl)methyl]naphthalene (MGR002) and their negative-tone imaging mechanism. EUV imaging experiments were performed using the high-numerical-aperture (NA=0.3), small-field EUV exposure tool (HINA). Patterning results showed the resolution of one resist to be 29nm at an EUV exposure dose of 18mJ∕cm2 and the obtainable aspect ratio to be as high as 2. Analyses by matrix-assisted laser desorption/ionization mass spectroscopy, Fourier transform infrared spectroscopy, and UV-visible absorption spectroscopy of EUV-exposed resists revealed that one reason for the good performance is that the negative-tone imaging mechanism involves both cross-linking and a change in polarity.