New silylation bi-layer resist system employing photochemical selective resist silylation

This paper describes a new silylation bi-layer resist system (SIBIS) that employs our previously reported photochemical selective silylation technique. Several different types of SIBIS are presented: normal-transfer SIBIS, image-reversal SIBIS, two-way normal-transfer/image-reversal SIBIS using the same resist materials, dry-development SIBIS, and SIBIS that uses an antireflective undercoating as a bottom layer. These SIBISs are applicable to optical, e-beam, and X-ray lithographies with proper selection of top-layer resist materials. This investigation primarily focuses on the top-and bottom-layer materials and silylation process conditions. Each of the SIBIS processes demonstrate fine pattern fabrication capability. The usefulness and superiority of SIBIS for LSI fabrication is confirmed.