A Single-Component Molecular Glass Resist Based on Tetraphenylsilane Derivatives for Electron Beam Lithography
Yake Wang, Jundi Yuan, Jinping Chen, Yi Zeng, Tianjun Yu, Xudong Guo, Shuangqing Wang, Guoqiang Yang, Yi Li
Abstract
High Resolution Image Download MS PowerPoint Slide A novel molecular glass (TPSiS) with photoacid generator (sulfonium salt group) binding to tetraphenylsilane derivatives was synthesized and characterized. The physical properties such as solubility, film-forming ability, and thermal stability of TPSiS were examined to assess the suitability for application as a candidate for photoresist materials. The sulfonium salt unit underwent photolysis to effectively generate photoacid on UV irradiation, which catalyzed the deprotection of the t -butyloxycarbonyl groups. It demonstrates that the TPSiS can be used as a ‘single-component’ molecular resist without any additives. The lithographic performance of the TPSiS resist was evaluated by electron beam lithography. The TPSiS resist can resolve 25 nm dense line/space patterns and 16 nm L/4S semidense line/space patterns at a dose of 45 and 85 μC/cm 2 for negative-tone development (NTD). The etching selectivity of the TPSiS resist to Si substrate is 8.6 under SF 6 /O 2 plasma, indicating a potential application. Contrast analysis suggests that the significant solubility switch within a narrow exposure dose range (18–47 μC/cm 2 ) by NTD is favorable for high-resolution patterns. This study supplies useful guidelines for the optimization and development of single-component molecular glass resists with high lithographic performance.