Semiconductor device and manufacturing method therefor
AssigneeRenesas Electronics Corporation
InventorsSenichirou Nagase, Tsuyoshi Kachi, Yoshinori Hoshino
Life of this patent
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Abstract
A deep trench which reaches a predetermined depth from one principal surface is formed in an element region of a semiconductor substrate. A TEOS oxide film and a polycrystalline silicon film are formed so as to fill the deep trench. In formation of a MOSFET and in formation of a protective insulating film on/over a surface of an element region by thermal oxidation, a silicon thermal oxide film grows, the TEOS oxide film contracts and the polycrystalline silicon film expands when oxidized and turning into a silicon oxide film, and thereby an embedded insulator is formed in the deep trench.
Claims14
A manufacturing method for a semiconductor device which includes a semiconductor element in which a first conductivity type first region and a second conductivity type second region which is formed in contact with the first conductivity type first region are alternately arranged and which performs electric current conduction between a first principal surface and a second principal surface of a semiconductor substrate, comprising the steps of:
- (a) forming the semiconductor element;
- (b) defining an element region on the first principal surface side of the semiconductor substrate;
- (c) forming a trench which reaches a first depth from the first principal surface of the semiconductor substrate in the element region;
- (d) introducing a first conductivity type first impurity through the trench and thereby forming the first conductivity type first region down to a second depth which is deeper than the first depth from the first principal surface of the semiconductor substrate;
- (e) introducing a second conductivity type second impurity through the trench and thereby forming the second conductivity type second region in contact with the first conductivity type first region along sidewall surfaces of the trench;
- and
- (f) forming an embedding element which includes a first film and a second film to fill the trench with the embedding element,
- wherein the step (a) of forming the semiconductor element includes the step (g) of forming a protective insulating film over the first principal surface of the semiconductor substrate which is located in the element region by thermal oxidation,
- wherein in the step (g) of forming the protective insulating film, the first film contracts, the second film expands and the embedding element turns into an embedded insulator by the thermal oxidation, and
- wherein after the step (g) of forming the protective insulating film, a state where the first film contracts is maintained and a state where the second film expands is maintained.
The manufacturing method for semiconductor device according to claim
- wherein the step (f) of forming the embedding element includes the steps of
- (k) forming a first oxidation block film which blocks the thermal oxidation in a state of being in contact with an inner-wall surface of the trench including the sidewall surfaces thereof,
- (l) forming the second film in contact with the first oxidation block film, and
- (m) forming the first film in contact with the second film.
Dependencies are inferred from the claim text.