Search of high-performance resists for 50 kV shaped-beam exposure

A search was made to find a high-performance resist to manifest the high-resolution advantage of 50 kV electron-beam exposure. Four resists were evaluated: Shipley SAL-601, AT&T/OCG CAMP-6, LBM KRS, and IBM TNS. All resists were found to have high contrast >3 and were capable of resolving <0.25 mu m line/space pairs at 3000 Angstrom thickness. With the exception of TNS, the resists demonstrate a high bulk sensitivity of <15 mu C/cm(2) at 50 kV. The IBM KRS resist was found to have the highest figure of merit. It was capable of resolving less than 0.10 mu m line/space at 4000 Angstrom thickness. Furthermore, at 8000-10000 Angstrom, a resolution of less than or equal to 0.25 mu m was obtained with a steep profile. The dry etch resistance of the resist relative to chrome was 2.4:1. This resist is not environmentally sensitive and needs no postexposure bake treatment. If KRS is made commercially available, it will be an outstanding resist for modern electron beam/x-ray mask making and direct write for device fabrication. (C) 1995 American Vacuum Society.