{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T05:17:15Z","timestamp":1788499035876,"version":"build-2803163510"},"reference-count":48,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T00:00:00Z","timestamp":1788307200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100011963","name":"Swiss Nanoscience Institute","doi-asserted-by":"crossref","award":["18.01 CAPOFOX"],"award-info":[{"award-number":["18.01 CAPOFOX"]}],"id":[{"id":"10.13039\/100011963","id-type":"DOI","asserted-by":"crossref"}]},{"award":["18.01 CAPOFOX"],"award-info":[{"award-number":["18.01 CAPOFOX"]}],"id":[{"id":"https:\/\/ror.org\/02mrd0686","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.3390\/polym18172148","type":"journal-article","created":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T14:35:29Z","timestamp":1788359729000},"page":"2148","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Nanoscale Roughness in Ultra-Thick Resists by Laser-Scanning Grayscale Direct-Write Lithography and Surface Smoothing"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-2169-9867","authenticated-orcid":false,"given":"Giulia","family":"Malvicini","sequence":"first","affiliation":[{"name":"Laboratory for Nano and Quantum Technologies, Paul Scherrer Institute (PSI), Forschungsstrasse 111, 5232 Villigen, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"given":"Dogukan","family":"G\u00fc\u00e7temur","sequence":"additional","affiliation":[{"name":"nanoLab, FHNW School of Life Sciences, Hofackerstrasse 30, 4132 Muttenz, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7101-0623","authenticated-orcid":false,"given":"Sina","family":"Saxer","sequence":"additional","affiliation":[{"name":"nanoLab, FHNW School of Life Sciences, Hofackerstrasse 30, 4132 Muttenz, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Jan","family":"Erjawetz","sequence":"additional","affiliation":[{"name":"XRnanotech, Switzerland Innovation Park Innovaare, Parkstrasse 1, 5234 Villigen, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6056-7530","authenticated-orcid":false,"given":"Helmut","family":"Schift","sequence":"additional","affiliation":[{"name":"Laboratory for Nano and Quantum Technologies, Paul Scherrer Institute (PSI), Forschungsstrasse 111, 5232 Villigen, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2297","DOI":"10.1103\/PhysRevB.38.2297","article-title":"X-ray and neutron scattering from rough surfaces","volume":"38","author":"Sinha","year":"1988","journal-title":"Phys. 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