10-NM SILICON LINES FABRICATED IN (110) SILICON

A technique which satisfies both high resolution and minimum linewidth fluctuation has been developed for fabrication of nanometer-scale Si structures. The technique is based on the development of resist with hexyl acetate and the anisotropic etching of Si with KOH. The combination of ZEP-520 resist and hexyl acetate developer is effective to improve the resolution and reduce pattern fluctuation in e-beam lithography. Resist lines less than 20 nm wide with a fluctuation less than 3 nm are obtained. When these lines, aligned in the <112> direction on a (110) Si wafer by using the fan-pattern method, are transferred to Si by KOH etching, linewidth fluctuation is reduced further because the (111) planes form the sidewalls. In addition, a feature size as small as 7 nm can be formed by additional etching using alcohol-added KOH solution.