Recent progress of EUV CAR-NTD with new developer for chemical stochastic defect reduction

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 issues were the stochastic, which will be become 'defectivity'. The analyzing summary of the stochastic factors in EUV lithography was reported, 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. The 1st preliminary results of newly proposed novel formulated organic solvent-based developer for negative-tone development of chemically amplified resist (CAR) with EUV exposure, called CAR EUV-NTD, were reported in last conference, SPIE AL 2023. In this paper, we will also focus on EUV CAR-NTD with New developer, continuously. The mechanisms of new developer behavior for pattern collapse improvement and chemical stochastic reduction. Also, the lithographic performance will also be reported, including underlayer influence.