Process for the autopositioning of a local field oxide with respect to an insulating trench
First Claim
1. A process for self-positioning a local field oxide with respect to an insulating trench formed in a silicon substrate, comprising the successive steps of:
- (a) forming at least one first insulating material coating on the substrate surface;
(b) forming a second insulating material coating on said first coating;
(c) anisotropically etching the first and second insulating material coatings until the region of the substrate in which the trench is to be formed is exposed;
(d) forming insulating spacers on the etched flanks of the first and second insulating material coatings;
(e) anisotropically said region of the substrate in order to produce the trench, the second etched insulating material coating and the spacers acting as a mask for said etching;
(f) eliminating the second etched insulating material coating and the spacers;
(g) forming insulating edges in the trench;
(h) filling the trench with a polycrystalline silicon;
(i) producing the local field oxide with a thermal oxidation of said polycrystalline silicon, the first etched insulating material coating acting as a mask for said thermal oxidation; and
(j) eliminating the first etched insulating material coating.
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Accused Products
Abstract
Process for the autopositioning of a local field oxide relative to an insulating trench.
This process consists of forming at least one first insulating coating on a silicon substrate, producing a second insulating coating on the first coating, anisotropically etching the first and second coating until the region of the substrate in which the trench is to be formed is exposed, forming insulating spacers on the etched flanks of the first and second coatings, anisotropically etching the substrate region in order to form the trench, the second etched coating and the spacers used as a mask for said etching, eliminating the mask, forming the insulating edges in the trench, filling said trench with a material and forming the field oxide.
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Citations
17 Claims
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1. A process for self-positioning a local field oxide with respect to an insulating trench formed in a silicon substrate, comprising the successive steps of:
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(a) forming at least one first insulating material coating on the substrate surface; (b) forming a second insulating material coating on said first coating; (c) anisotropically etching the first and second insulating material coatings until the region of the substrate in which the trench is to be formed is exposed; (d) forming insulating spacers on the etched flanks of the first and second insulating material coatings; (e) anisotropically said region of the substrate in order to produce the trench, the second etched insulating material coating and the spacers acting as a mask for said etching; (f) eliminating the second etched insulating material coating and the spacers; (g) forming insulating edges in the trench; (h) filling the trench with a polycrystalline silicon; (i) producing the local field oxide with a thermal oxidation of said polycrystalline silicon, the first etched insulating material coating acting as a mask for said thermal oxidation; and (j) eliminating the first etched insulating material coating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification