Novel organometallic EUV photoresist for thermal development

Abstract

EUV photolithography is considered the next-generation lithography for its capability to implement high-resolution patterns, which are essential in the semiconductor industry. Among many materials, metal-adopted EUV photoresists have been studied vigorously due to the high EUV cross-section of metal. In this study, organometallic molecular compounds have been investigated for EUV photoresist. The novel structure of the photoresist consists of metal and an N-heterocyclic carbene ligand. Additionally, this study introduced pioneering development technology called thermal development to overcome the pattern collapse issue associated with wet development. The pattern successfully formed by annealing the substrate after exposure using the difference in sublimation temperature between the exposed and unexposed areas. The novel photoresist has been successfully synthesized, characterized with NMR and XRD and exposed with ArF and EUV optical sources, forming patterns of 130nm an 350nm successfully with thermal development. EUV reactivity improvement of the photoresist has been followed. The improved photoresist has been synthesized successfully, characterized with NMR and XRD, and exposed with EUV optical sources, forming patterns of 40nm with wet development and 80nm with thermal development. This research provides a novel type of EUV photoresist capable of new thermal development.