Novel Process for Patterning Photoresists Suitable for Metal RIE Advanced Ic Fabrication
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
Large changes in the linewidths of a patterned photoresist layer result when the lines pass over a steep topographical step in the presence of a highly reflecting metallized layer underneath the resist. Such linewidth variations will be transferred to the metal layer upon subsequent reactive ion etching (RIE) of the latter. This problem can be eliminated by applying a thin layer of commercially available anti-reflection coating (ARC) material on the metal and baking it so as to render it essentially insoluble with the solvent exposures employed to develop the photoresist layer added and processed subsequently. The ARC serves to minimize unwanted effects of light scattering from the sidewall surface and allows greater freedom in optimizing light exposure and processing parameters for the resist layer.