摘要 |
A photoresist exposure process is disclosed which produces features which are substantially smaller than the aperture dimension of the mask used to make the feature. The smaller feature size results from a double exposure of the photoresist, combined with a double baking process to create the features in the photoresist. The double baking process thins the layer of photoresist, prior to the second exposure, thereby improving the resolution of the mark created by the second exposure on the photoresist. The process also uses a binary bias mask through which the first exposure is made, which overlaps with the area of the second exposure, to allow a process tolerance for the realignment of the mask over the wafer for the second exposure.
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