Process for fabricating a semiconductor device
AssigneeOki Electric Industry Co., Ltd.
InventorJun Kanamori
Life of this patent
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Abstract
In a process for fabricating a semiconductor device having a trench at the surface of a semiconductor substrate, a first mask layer is formed to have an opening whose side is set back from an area where the trench will be formed, a second mask layer is formed on the side of the opening of the first mask layer with an opening corresponding to the area where the trench will be formed, and an etching is performed using the first and the second mask layer as a mask to form the trench.
Claims9
A process for fabricating a semiconductor device which includes a semiconductor substrate having a trench formed at a predetermined area in a surface thereof, said trench having a rounded corner at the surface of said substrate, wherein said process comprises the steps of:
- (a) forming a first mask layer on said surface of said substrate, said first mask layer having an opening therein with a side spaced from said predetermined area;
- (b) forming a second mask layer on said side of the opening of said first mask layer, said second mask layer having an opening therein with a side wall substantially aligned with said predetermined area where said trench is to be formed;
- (c) forming a trench in said substrate at said predetermined area using said first and second mask layers as a mask;
- (d) removing said second mask layer;
- and
- (e) dry etching said substrate at said predetermined area using said first mask layer as a mask, whereby the edge of said trench, which has a higher etching rate than the remainder of said substrate under dry etching, is rounded.
Dependencies are inferred from the claim text.