Mask-aligner Talbot lithography using a 193nm CW light source

We present and discuss Talbot mask-aligner lithography, relying on a continuous wave laser emitting at 193nm for the illumination. In this source, a diode laser at 772nm is amplified by a tapered amplifier in master-oscillator power-amplifier configuration and frequency-quadrupled in two subsequent enhancement cavities using lithium triborate and potassium fluoro-beryllo-borate nonlinear crystals to generate the emission at 193 nm. The high coherence and brilliance of such an illumination source is predestined for plane wave mask-aligner illumination, crucial in particular for high-resolution lithographic techniques such as Talbot lithography and phase-shift masks. Talbot lithography takes advantage of the diffraction effect to image periodic mask features via self-replication in multiples of the Talbot distance behind the photomask when exposed by a plane wave. By placing a photoresist-coated wafer in one of the Talbot planes, the mask pattern is replicated in the resist. Periodic patterns with diverse shapes are required for wire grid polarizers, diffraction gratings, and hole arrays in photonic applications as well as for filters and membranes. Using an amplitude mask with periodic structures, we demonstrate here with such a technique sub-micron feature sizes for various designs at a proximity gap of 20 mu m.


Published in:
Optical Microlithography Xxxi, 10587, 105870W
Presented at:
Conference on Optical Microlithography XXXI, San Jose, CA, Feb 27-Mar 01, 2018
Year:
Jan 01 2018
Publisher:
Bellingham, SPIE-INT SOC OPTICAL ENGINEERING
ISSN:
0277-786X
1996-756X
ISBN:
978-1-5106-1667-7
Keywords:
Laboratories:




 Record created 2018-12-26, last modified 2019-10-07


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