Electron beam lithography with reduced charging effects

Abstract

A direct-writing electron beam is used for defining features in a resist layer and hence ultimately in an underlying workpiece, such as in a phase-shifting mask substrate or a semiconductor integrated circuit wafer. The resist layer is located on a top major surface of the workpiece. In a specific embodiment, the resist layer is located underneath a protective layer of polyvinyl alcohol ("PVA"); and a grounded conductive layer, such as a conductive organic layer, is located on the protective layer. After exposing the top major surface of the resulting structure to the direct-writing electron beam, the following steps are performed: (1) a plasma etching completely removes the entire thickness of the conductive layer as well as a small fraction of the thickness of the PVA layer; (2) the PVA layer is then completely removed by dissolving it in water; (3) another plasma etching removes a small fraction of the thickness of the resist layer, including any unwanted residues; and (4) the resist layer is developed.

Dependencies are inferred from the claim text.