Multi-Step Contour Etching Process
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
A composite film of varying thickness and etching properties, which is patterned with a dissimilar masking material (e.g., photoresist), must often be etched to obtain a prescribed contour or slope while maintaining dimensional control. The slopes and dimensional loss of etched features are strong functions of film composition, thickness variations and etching selectivities. A multi-step contour etching process is provided that significantly reduces these process sensitivities. The etching process is designed to approximate the desired profile 11 by alternating etching and mask erosion processes. The expected result of a "step" approximation of the desired profile 11 is modified by an observed rounding of the step edges. However, the rounding may be used to more closely approximate the desired profile 11.