Semiconductor device and manufacturing method of the same
First Claim
1. A semiconductor device comprising:
- a semiconductor substrate comprising a front surface and a back surface, a recess portion being formed from the back surface toward the front surface;
a MOS structure formed on the front surface of the semiconductor substrate; and
a back surface electrode formed in the recess portion, wherein the semiconductor device is configured to form a current flow between the front and back surfaces of the semiconductor substrate.
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Accused Products
Abstract
Thinning a semiconductor substrate has been needed for reducing on-resistance in a semiconductor device such as a vertical MOS transistor, IGBT, or the like where a high current flows in the semiconductor substrate in a vertical direction. In this case, the thinning is performed to the extent that the semiconductor substrate does not warp with a heat treatment, so that there is a limitation in reduction of on-resistance. In the invention, openings such as trench holes are formed on a back surface side of a semiconductor substrate. Then, a drain electrode is formed being electrically connected with bottoms of these openings. In this case, a current path is formed short corresponding to the depths of the openings, thereby easily achieving low on-resistance.
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Citations
20 Claims
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1. A semiconductor device comprising:
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a semiconductor substrate comprising a front surface and a back surface, a recess portion being formed from the back surface toward the front surface;
a MOS structure formed on the front surface of the semiconductor substrate; and
a back surface electrode formed in the recess portion, wherein the semiconductor device is configured to form a current flow between the front and back surfaces of the semiconductor substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of manufacturing a semiconductor device, comprising:
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forming a MOS structure on a front surface of a semiconductor substrate of a first general conductivity type;
forming a photoresist pattern on a back surface of the semiconductor substrate;
forming a recess portion by etching the semiconductor substrate using the photoresist pattern as a mask; and
forming a back surface electrode in the recess portion. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification