Exploring stochastic reduction and lithographic performance by using EUV CAR-NTD

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 requirement, even by using the latest qualifying EUV resist materials. The critical issues were stochastic properties, classified as photon stochastic and chemical stochastic, which can lead to defectivity. There are three types of chemical stochastic effects in lithography: material randomness in the film, randomness in material diffusion and reaction, and development uniformity. The chemical stochastic reduction is necessary to improve lithographic performance. Chemically Amplified Resist (CAR) with negative-tone developer with EUV exposure called CAR EUV-NTD was reported at the previous SPIE AL 2023 and 2024 conferences, demonstrating high potential for HVM. This paper describes recent progress of EUV CAR-NTD with new developer for chemical stochastic reduction. Regarding the development uniformity, it was observed that organic solvent-based development exhibited better uniformity compared to alkali aqueous-based developer. Additionally, the use of a new developer was found to be effective in improving the pattern collapse, and the behavior of this new developer will be discussed. Also, new functionalized materials will be discussed, such as new type of material with a high absorption unit introduced, and a new type of photo acid generator connected to a Photo Decomposable Quencher (PCP). The latest lithographic performance will also be reported with various features.