摘要 |
An insulation film is formed on a semiconductor substrate. A stopper film, which has a large etching selectivity relative to the insulation film and has a first film thickness, is formed on the insulation film. A first mask material, which has a second film thickness that is less than the first film thickness, is formed on the stopper film. A first mask is formed by patterning the first mask material. An opening portion is formed by etching the stopper film using the first mask. The opening portion is filled with a second mask material. A second mask of the second mask material is formed by removing the stopper film. The insulation film is etched using the second mask.
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