Nanoscale roughness in ultra-thick resists by laser-scanning grayscale direct-write lithography and surface smoothing
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Author (Corporation)
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2026
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01A - Journal article
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Polymers
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18
Issue / Number
17
Pages / Duration
2148
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MDPI
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Abstract
Surface roughness at the nanometer scale limits the optical performance of reflective components for X-ray and extreme ultraviolet beam shaping. While sub-nanometer roughness can be achieved by polishing planar substrates, it remains challenging for continuous three-dimensional topographies fabricated by grayscale direct-write lithography in polymer resists. In this work, mm-long linear grayscale slopes are introduced as a calibration platform to distinguish between form, waviness, and roughness contributions. Process optimization reduces artifacts such as gray-value discretization and stitching, while replication into PMMA combined with the TASTE process enables a reduction of intrinsic roughness below 2 nm. Laser scanning confocal and atomic force microscopy are used as complementary techniques to assess surface quality across spatial scales. The results provide insight into the origin of roughness in novolak-based resists and its evolution through the fabrication chain, highlighting material limitations and paths toward smooth polymer optics with sub-nanometer roughness.
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2073-4360
Language
English
Created during FHNW affiliation
Yes
Strategic action fields FHNW
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Published
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peer-reviewed
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Gold
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Citation
Malvicini, G., Güçtemur, D., Saxer, S., Erjawetz, J., & Schift, H. (2026). Nanoscale roughness in ultra-thick resists by laser-scanning grayscale direct-write lithography and surface smoothing. Polymers, 18(17), 2148. https://doi.org/10.3390/polym18172148