Patterning of metal acetylacetonate complex via extreme-ultraviolet light-induced chemical reaction and straightforward thermal development process

Abstract

Extreme-ultraviolet light (EUV) lithography is a transformative technology used in semiconductor manufacturing. However, developing compatible photoresist (PR) materials remains challenging. Conventional EUV PRs require wet development, leading to mechanical degradation such as pattern collapse mediated via capillary forces. Herein, we propose Fe(styrene-acac)₃ as a dry processable EUV PR candidate, utilizing straightforward thermal development (at 100 °C, 17 Pa) for pattern formation without the need for chemical vapor treatment or immersion in developer solutions. The organometallic compound, comprising Fe for high EUV absorption and styrene-acetylacetone (acac) ligand for volatility, reactivity (half-saturation doses for Dh of 543 mJ/cm2 and 437 mJ/cm2 for EUV and deep-ultraviolet light (DUV), respectively), and uniform film formation (root-mean-square roughness: 0.312 nm), yields promising results in line patterning (a half-pitch of 1 μm with DUV, and 80 nm with EUV) by employing wet development and thermal development methods. Moreover, we suggest that secondary electron attachment to the styrene moieties of Fe(styrene-acac)₃, followed by anionic polymerization, constitutes an EUV-induced chemical reaction that prevents the evaporation of Fe(styrene-acac)₃ in the exposed area. Our findings advance the development of dry-processable EUV PRs and offer potential solutions to the challenges faced by the semiconductor industry in advancing lithographic precision. © 2024 Elsevier Ltd