A CA Resist with High Sensitivity and Sub 100nm Resolution for Advanced Mask Making

摘要

Recently, there is significant interest in using CA resists for electron beam (E-Beam) applications including mask making, direct write, and projection pr8inting. CA resists provide superior lithographic performnace in comparison to traditional non-CA E-beam resists in particulr high contrast, resolution, and sensitivity. However, most of the commercially available CA resists have the concern of airborne base contaminants and sensitivity of PAB and/or PEB temperatures. In this presentation, we will discuss a new improved ketal resist system referred to as KRS-XE which exhibits excellent lithography, is robust toward airborne base, compatible with 0.263N TMAH aqueous developer and exhibits a large PAB/PEB latitude. With the combination of a high performance mask making E-beam exposure tool, high kV (75kV) shaped beam system EL4+ and the KRS-XE resist, we have printed 75nm lines/space features with excellent profile control at a dose of 13 mu C/cm~2 at 75kV. The shaped beam vector scan system used here provides an unique property in resolving small feautres in lithography and throughput. Overhead in EL4+ limits the systems ability to fully exploit the sensitivity of the new resist for throughput. The EL5 system has sufficiently low overhead that it is projected to print a 4X, 16G DRAM mask with OPC in under 3 hours with the CA resist. We will discuss the throughput advantages of the next generation EL5 system over the existing EL4+.