| 摘要 |
<p>A bilevel photoresist system (10) of two organic photoresists, both sensitive to deep ultraviolet (UV) radiation from the same deep UV source (e.g., Xe-Hg) and suitable for use in patterning a substrate of high reflectivity in the deep UV, comprises a top layer of a negative photoresist (e.g., the azide-phenolic resin diazidodiphenyl sulfone mixed into poly (p-vinylphenol)) having a thickness of about 0.5 micron, and a bottom layer of positive photoresist (e.g., polymethyl methacrylate), having a thickness about 1 or 2 microns. The top layer is thus of sufficient thickness to be substantially opaque to the deep UV radiation from the source. The top layer is patterned by projecting the deep UV light to form an image therein which is complementary to the ultimately desired pattern, followed by treating the top layer, with a suitable solvent which attacks and removes the unexposed portions thereof. Then the bottom layer is patterned by directing a collimated (parallel) beam from the deep UV source onto the bottom layer, using the thus patterned top layer as a shadow mask, followed by treating the bottom layer with a suitable solvent which attacks and removes the portions of the bottom layer thus previously exposed to the UV light. Then the thus patterned photoresist layers can be used as a protective mask for etching the top surface of the substrate in accordance with the desired pattern. </p> |
