High sensitivity non-CAR resists for EUV and EB lithography

A new non-CAR hemicellulose resist is proposed for use in high-NA EUV lithography. This resist has high sensitivity (EUV dose 34.4 mJ/cm²) and high resolution (half-pitch of more than 16 nm) compared to conventional chain scission resists. Additionally, the process flow is very simple (no need for PEB) and the resist film is stable throughout the process. It was confirmed that the RIE selectivity ratio (Si/resist) of the non-CAR hemicellulose resist was 3.7, and am L/S pattern was obtained with a Si depth of 120.4 nm and a half-pitch of 18 nm. Furthermore, a new resist process, PreMi (pre-exposure metal insertion), was proposed. The PreMi process is expected to improve the fabrication properties, increase sensitivity and contrast, and reduce defects. Te and Sn were employed as metal types in this study, and EUV L/S patterns of PreMi-Te and PreMi-Sn were obtained. It was confirmed the PreMi process improved the fabrication properties of the no-PreMi process by a factor of 2. The non-CAR hemicellulose resist and PreMi process have great potential for use in high-NA EUV lithography.