Direct-write afocal electron-beam semiconductor lithography

Abstract

A technique is describe for effecting very-high resolution semiconductor lithography using direct-write afocal electron-beam exposure of a sensitized wafer. A positioning mechanism and needle-like probe similar to those used in scanning-tunneling microscopy are used in conjunction with a controllable electron field emission source to produce a near-field electron beam capable of exposing an electron-beam sensitive resist on a wafer surface. Conventional e-beam resists are used. The technique can be used in conjunction with scanning-tunneling-like operation of the apparatus to record the appearance and nature of the wafer surface, thereby providing information about the location of underlying features. This location information can be used to assist in aligning the exposure patterns to existing structures in the semiconductor wafer. A multi-probe embodiment with separately controllable field emission sources provides for improved productivity by permitting contemporaneous exposure of multiple sites on a single wafer.

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