posted on 2022-12-29, 06:29authored byZhihao Wang, Jinping Chen, Tianjun Yu, Yi Zeng, Xudong Guo, Shuangqing Wang, Timothée Allenet, Michaela Vockenhuber, Yasin Ekinci, Guoqiang Yang, Yi Li
Nonchemically
amplified resists based on triphenyl sulfonium triflate-modified
polystyrene (PSTS) were prepared by a facile method of modification
of polystyrene with sulfonium groups. The uploading of the sulfonium
group can be well-controlled by changing the feed ratio of raw materials,
resulting in PSTS0.5 and PSTS0.7 resists with
sulfonium ratios of 50 and 70%, respectively. The optimum developer
(methyl isobutyl ketone/ethanol = 1:7) is obtained by analyzing contrast
curves of electron beam lithography (EBL). PSTS0.7 exhibits
a better resolution (18 nm half-pitch (HP)) than the PSTS0.5 resist (20 nm HP) at the same developing conditions for EBL. This
novel resist platform was further evaluated by extreme ultraviolet
lithography, and patterning performance down to 13 nm HP at a dose
of 186 mJ cm–2 with a line edge roughness of 2.8
nm was achieved. Our detailed study of the reaction and patterning
mechanism suggests that the decomposition of the polar triflate and
triphenyl sulfonium groups into nonpolar sulfide or polystyrene plays
an important role in the solubility switch.