Progress in STED-inspired sub-diffractional lithography of epoxides
Sprache des Titels:
Englisch
Original Buchtitel:
73rd Annual Meeting of the Austrian Physical Society (ÖPG)
Original Kurzfassung:
The past two decades have seen substantial advancements in direct laser writing by
two-photon lithography, enhanced by techniques adapted from stimulated emission
depletion (STED) microscopy. 1 Initially, STED-inspired lithography was predominantly
applied to radical polymerizations, especially with acrylates and methacrylates, 2
while cationic polymers, particularly epoxides, crucial in semiconductor clean-room
technology, did not benefit from this method.
Recently, we investigated a resist comprising 3,4-epoxycyclohexylmethyl 3,4
epoxycyclohexanecarboxylate (EPOX) as monomer, triarylsulfonium
hexafluoroantimonate salt as starter and 2-isopropylthioxanthone (ITX) as a photo-
sensitizer. Using a 780 nm femtosecond laser for two-photon excitation and a 660
nm continuous wave laser for depletion, we achieved 125 nm structure sizes. 3
Utilizing 2-chlorothioxanthone (CTX) instead of ITX, allowed for writing feature sizes
down to 83 nm. 4, which is roughly l/10 of the excitation wavelength. This holds
promise of delivering feature sizes on par with those obtained in acrylate
polymerization5.
In this contribution, we will present our latest progress on STED-inspired lithography
of epoxides.
Forschungs-