Initial Stage of Nanoscale Imaging in Positive Tone Extreme UV Photoresists: The Influence of the Polymer Sequence

Journal Article · Fri Dec 19 00:00:00 EST 2025 · ACS Applied Polymer Materials

DOI:https://doi.org/10.1021/acsapm.5c03773· OSTI ID:3012469

Houle, Frances A. ^[1]; Hinsberg, William ^[2]; Milton, Jacob R. ^[1]; Zhang, Qi ^[1]; Wang, Cheng ^[1]; Blau, Samuel M. ^[1]

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1. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
2. Columbia Hill Technical Consulting, Fremont, CA (United States)

Photolithographic patterning using extreme ultraviolet (EUV, 92.5 eV) light is a radiolytic process that initially forms electrons, radical cations, anions, and neutral radicals in the polymeric photoresist matrix. These species may participate in the chemical reactions that define the ultimate resolution of the printed image, and their concentrations and nanometer-scale stochastic variations in their formation influence printed image quality. Proposals have been made that polymer chain uniformity may be advantageous in reducing stochastics due to spatial inhomogeneities, and this aspect of radiolysis is examined in this work. We have simulated the initial subpicosecond stages of the imaging process for a series of photoresist films that are identical in composition but vary in their polymer chain structures. We use detailed, physically accurate stochastic reaction-diffusion calculations to evaluate the influence of defined sequence and random copolymer structures on radiolytic spur formation, i.e., a cluster of species formed by electron-polymer interactions that defines the initial spatial characteristic of the imaging process. Predictions of electron thermalization in the present work are shown to be consistent with the literature, indicating that our overall computational approach for ultrafast nanoscale processes is sound. The computational results show that the polymer sequence has no significant effect on the spur composition. This suggests that any potential imaging improvements to be gained by sequence control must originate from postimaging lithographic process steps.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Scientific User Facilities Division (SC-22.3 ); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-05CH11231
• Other Award/Contract Number: DE-AC02-342-05CH11231
• OSTI ID: 3012469
• Alternate ID(s): OSTI ID: 3016265
• Journal Information: ACS Applied Polymer Materials, Journal Name: ACS Applied Polymer Materials Journal Issue: 1 Vol. 8; ISSN 2637-6105
• Publisher: ACS Publications
• Country of Publication: United States
• Language: English

Related Subjects

Absorption
Anions
Chemical structure
Dissociation
EUV photolithography
Polymers
defined sequence polymers
poly(hydroxystyrene)
poly(t-butyl methacrylate)
radiolysis