Proceedings Article | 21 November 2023
KEYWORDS: Stochastic processes, Extreme ultraviolet, High volume manufacturing, Standards development, Materials processing, Lithography, Extreme ultraviolet lithography, Chemical analysis, Photoresist processing, Materials properties
In 2019, finally, extreme ultraviolet (EUV) lithography has been applied to high volume manufacturing (HVM). However, the performance of EUV resist materials are still not enough for the expected HVM requirements, even by using the latest qualifying EUV resist materials. The critical issue is the stochastic issues, which will be become defectivity. The analyzing summary of the stochastic factors in EUV lithography was classified, which described 2 (two) major stochastic issues, which are Photon stochastic and Chemical stochastic. In the past, speaking of the stochastic issue was basically considered from low photon number from EUV light source, which means photon shot noise. It was still critical concerning point, even with recent progress on source power improvement. However, the stochastic issue is not only from them but also from EUV materials and processes, called Chemical stochastic. The Chemical stochastic means caused from resist materials and processes for lithography, materials uniformity in the film, reactive uniformity in the film, and dissolving behavior with the developer. From a material point of view, chemically amplified resist (CAR) has still high potential for high volume manufacturing. Therefore, we have been studying to improve CAR performance for next generation node. In this paper, we will focus on Chemical stochastic improvement, like materials location uniformity and dissolving behavior improvement by using negative-tone development (NTD, using organic solvent-based developer). CAR-NTD had a potential for improving Chemical stochastic because of their properties, which were low swelling and smooth dissolving behavior. However, the pattern collapse was easily observed for preparing fine patterns with the standard developer. Newly proposed novel formulated organic solvent-based developer will be expected to improve the pattern collapse issue and Chemical stochastic. Lithographic performance will also be reported and discussed.
