High NA: Enabling Single Exposure for Metal Logic Designs

Abstract

We will present a detailed study on pitch 20 nm (P20) and pitch 18 nm (P18) metal logic designs, including regular tip-to-tip (T2T) and logic structures for bright field (BF) mask design in combination with dry metal-oxide-resist. We show the performance of such structures for various pupils and dry resist processing combinations. The highlight of P20 T2T structure is that we can print 13 nm T2T-CD (critical dimension) with local CD uniformity (LCDU) < 3nm, whereas P18 nm structure can be printed with T2T-CD 18 nm having LCDU < 3 nm in a single High-NA EUV exposure. Further, using directional etch technique at resist, in P18 T2T structure we can even push T2T-CD to ~9 nm with LCDU ~ 3 nm. To align the study further with industrial applications, we explore large area defectivity analysis through e-beam inspection for P20 metal logic structure after stack etch. We believe our results will promote single patterning technology for metal logic design for damascene process.