摘要 |
A process for producing multiple undercut profiles in a single material. A resist pattern is applied over a work piece and a wet etch is performed to produce an undercut in the material. This first wet etch is followed by a polymerizing dry etch which produces a polymer film in the undercut created by the first wet etch. The polymer film prevents further etching of the undercut portion during a second wet etch. Thus, an undercut profile can be obtained having a larger undercut in an underlying portion of the work piece, utilizing only a single resist application step. The work piece may be a multilayer work piece having different layers formed of the same material, or it may be a single layer of material. The process can be used to manufacture a base structure for a conical cathode emitter tip.
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