Method of manufacturing semiconductor device
AssigneeRenesas Electronics Corporation
InventorYu NAGAHAMA
Life of this patent
Estimating the term…
Abstract
The reliability of the semiconductor device is improved. A field plate electrode FP is formed inside the trench TR via an insulating film IF1. The other part of the field plate electrode FP is selectively retracted toward the bottom of the trench TR so that a part of the field plate electrode FP remains as a lead-out part FPa. A silicon oxide film OX1 is formed on the upper surface of the field plate electrode FP by thermal oxidation. The insulating film IF1 located on the upper surface TS of the semiconductor substrate SUB and the silicon oxide film OX1 are removed, and the insulating film IF1 is retracted so that its upper surface position is lower than the upper surface position of the field plate electrode FP.
Claims14
A method of manufacturing a semiconductor device comprising:
- (a) providing a semiconductor substrate of a first conductivity type having an upper surface and a lower surface;
- (b) after (a), forming a trench in the semiconductor substrate so as to reach a predetermined depth from the upper surface of the semiconductor substrate toward the lower surface of the semiconductor substrate;
- (c) after (b), forming a first insulating film on the upper surface of the semiconductor substrate and inside the trench;
- (d) after (c), forming a first conductive film on the first insulating film so as to fill the inside of the trench;
- (e) after (d), removing the first conductive film located outside the trench to form the first conductive film remaining inside the trench as a field plate electrode;
- (f) after (e), so that a part of the field plate electrode remains as a lead-out part, selectively retracting the other part of the field plate electrode toward the bottom of the trench;
- (g) after (f), forming a first silicon oxide film on the upper surface of the field plate electrode by thermal oxidation;
- (h) after (g), removing the first insulating film located on the upper surface of the semiconductor substrate and the first silicon oxide film, and retracting the first insulating film located inside the trench toward the bottom of the trench so that the position of the upper surface of the first insulating film located inside the trench is lower than the position of the upper surface of the field plate electrode in cross-sectional view;
- (i) after (h), forming a gate insulating film inside the trench on the first insulating film and forming a second insulating film so as to cover the field plate electrode exposed from the first insulating film;
- (j) after (i), forming a second conductive film on the gate insulating film, the second insulating film, and the first insulating film to fill the inside of the trench;
- and
- (k) after (j), removing the second conductive film located outside the trench to form the second conductive film remaining inside the trench on the field plate electrode as a gate electrode,
- wherein the second conductive film formed on the first insulating film and the second insulating film in contact with the lead-out part by (j) is removed by (k).
Dependencies are inferred from the claim text.