Semiconductor device and manufacturing method thereof
First Claim
1. A method of manufacturing a semiconductor device comprising the steps of:
- forming a multilayer film, which includes a silicon oxide layer, a polycrystalline silicon layer having a thickness, above the silicon oxide layer and a silicon nitride layer having a first thickness, above the polycrystalline silicon layer, on a main surface of a silicon substrate;
patterning said multilayer film and etching a trench for element separation in said silicon substrate;
forming an inner wall silicon oxide film at a thickness which covers inner walls of said trench by oxidizing the inner wall surfaces which include sidewalls of said multilayer film;
forming a trench oxide layer so as to fill in the trench which is covered with said inner wall silicon oxide film and so as to contact a top surface of said silicon nitride layer;
polishing said trench oxide layer and said silicon nitride layer through CMP polishing reducing the first thickness of said silicon nitride layer to a second thickness leaving an upper surface of the silicon nitride layer exposed and forming a recess in the trench oxide layer such that an upper surface of the trench oxide is below the upper surface of the silicon nitride layer;
etching the trench oxide layer after, CMP polishing to reduce the height by an amount no greater than the thickness of said inner wall silicon oxide film for the purpose of height adjustment of a trench separation band.
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Accused Products
Abstract
A semiconductor device as well as a method of manufacturing a semiconductor device wherein a wide trench separation band is formed without causing the scooping out of the silicon substrate can be gained.
The process is provided with the step of forming a multilayer film on a silicon substrate, the step of patterning the multilayer film and of etching the silicon substrate so as to create a trench, the step of forming an inner wall silicon oxide film on the inner wall surface of the trench, the step of forming a trench oxide layer so as to fill in the trench, the step of polishing the trench oxide layer through CMP polishing so as to expose the silicon nitride layer and the step of etching the trench oxide film, which has undergone the CMP polishing, by a thickness no more than the thickness of the inner wall silicon oxide film.
27 Citations
13 Claims
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1. A method of manufacturing a semiconductor device comprising the steps of:
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forming a multilayer film, which includes a silicon oxide layer, a polycrystalline silicon layer having a thickness, above the silicon oxide layer and a silicon nitride layer having a first thickness, above the polycrystalline silicon layer, on a main surface of a silicon substrate;
patterning said multilayer film and etching a trench for element separation in said silicon substrate;
forming an inner wall silicon oxide film at a thickness which covers inner walls of said trench by oxidizing the inner wall surfaces which include sidewalls of said multilayer film;
forming a trench oxide layer so as to fill in the trench which is covered with said inner wall silicon oxide film and so as to contact a top surface of said silicon nitride layer;
polishing said trench oxide layer and said silicon nitride layer through CMP polishing reducing the first thickness of said silicon nitride layer to a second thickness leaving an upper surface of the silicon nitride layer exposed and forming a recess in the trench oxide layer such that an upper surface of the trench oxide is below the upper surface of the silicon nitride layer;
etching the trench oxide layer after, CMP polishing to reduce the height by an amount no greater than the thickness of said inner wall silicon oxide film for the purpose of height adjustment of a trench separation band. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
said trench separation band comprises a first trench separation band portion and a second trench separation band portion which is greater than said first trench separation band portion. -
9. The method of manufacturing a semiconductor device according to claim 1, wherein said trench is created in said silicon substrate in a band form which includes interconnection films which contact a top surface of the interlayer insulating film on the silicon substrate in the plan view.
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10. The method of manufacturing a semiconductor device according to claim 9, wherein said wires are first and second wire arranged in parallel and said trench is created as a region in a band form which includes said first and second wires in the plan view.
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11. A semiconductor device manufactured in accordance with the method of claim 10, wherein
said trench separation band comprises a first trench separation band portion and a second trench separation band portion which is wider than said first trench separation band portion. -
12. A semiconductor device manufactured in accordance with the method of claim 9, wherein
said trench separation band comprises a first trench separation band portion and a second trench separation band portion which is wider than said first trench separation band portion. -
13. A semiconductor device manufactured in accordance with the method of claim 1, wherein
said trench separation band comprises a first trench separation band portion and a second trench separation band portion which is wider than said first trench separation band portion.
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Specification