Method for forming a sloped surface having a predetermined slope

Abstract

In accordance with the invention, a workpiece is provided with a sloped surface of predetermined slope by the steps of: a) coating the workpiece with resist, b) exposing the resist-coated workpiece to activating radiation which varies linearly in the direction of slope, c) developing the exposed resist, and d) etching the resulting structure to form an intaglio pattern in the workpiece surface. In a preferred embodiment, the resist is positive working photoresist and the exposure is through an exposure mask comprising a sequence of triangles having their bases aligned along a line defining the higher edge of a downward sloped region and their apices extending along a line defining the lower edge. After development, the structure is reactively ion etched.