| 摘要 |
In a method of making a negative photoresist image as for lithography, a positive resist is exposed by a light radiation through a phase shift mask as a first exposing step. Next, the positive resist is changed in its character by means of baking the substrate in an amine gas atmosphere such as ammonium, to make an exposed portion insoluble by developer. Next, an unexposed potion of the positive resist is exposed a second time to a light radiation using a second mask. After the second exposing step, the positive resist is developed to remove the unexposed portion. The phase shift mask has a fine pattern constituted mask membrane and an opening placed alternatively. And the opening is covered by attenuator intermittently. The second mask has an opening so that at least one portion unexposed by the first exposing step is exposed by the second exposing step.
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