LEEPL mask fabrication using SOI substrates

Abstract

We have prepared 100-mm and 200-mm 1X stencil masks for low energy electron-beam proximity projection lithography (LEEPL) using silicon on insulator (SOI) substrates. We chose 200-mm without frame type format for production mask and 100-mm with NIST-like frame type for developing. And we employed COSMOS (complementary stencil masks on strut-supports) structure proposed by SONY to suppress in-plane distortion (IPD) of membrane. Our 100-mm mask contains 70-nm node device patterns. The critical dimension (CD) uniformity of a 100-nm width line patterns was 5.6 nm in range within 20-mm square area. The CD linearity of the line patterns was 5.5 nm in range throughout the range of 80-to 300-nm width. In our 200-mm mask, 100-nm width line patterns and 150-nm width hole patterns were successfully fabricated within 46-mm square area.