Semiconductor device fabrication method and semiconductor device
AssigneeLapis Semiconductor Co., Ltd.
InventorMasataka Yoshinari
Life of this patent
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Abstract
A method of fabricating a semiconductor device includes forming a first semiconductor region at a front surface of a substrate, the first semiconductor region including an active element that regulates current flowing in a thickness direction of the substrate; grinding a rear surface of the substrate; after the grinding, performing a first etching that etches the rear surface of the substrate with a chemical solution including phosphorus; after the first etching, performing a second etching that etches the rear surface with an etching method with a lower etching rate than the first etching; and after the second etching, forming a second semiconductor region through which the current is to flow, by implanting impurities from the rear surface of the substrate.
Claims14
A method of fabricating a semiconductor device in which current flows in a thickness direction of a substrate, the method comprising:
- forming a first semiconductor region at a front surface of the substrate, the first semiconductor region including an active element;
- forming a damaged layer on a rear surface of the substrate;
- etching the rear surface of the substrate self-consistently by a chemical solution to remove the damaged layer;
- removing impurities adhered to the semiconductor substrate in association with the removing of the damaged layer;
- forming a buffer layer by ion-implantation from the rear surface of the substrate;
- and
- forming a second semiconductor region by implanting impurities of P-type conductivity from the rear surface of the substrate,
- wherein a density per unit volume of phosphorous in the second semiconductor region is at most ⅕ of a density of the impurities of the P-type conductivity in the buffer layer.
A method of fabricating a semiconductor device, the method comprising:
- forming a first semiconductor region at a front surface of a substrate, the first semiconductor region including an active element;
- grinding a rear surface of the substrate;
- etching the rear surface of the substrate by a chemical solution to produce a smooth mirror finish;
- washing the rear surface of the substrate after the etching;
- forming a buffer layer of N-type conductivity by ion-implantation from the rear surface of the substrate;
- and
- forming a second semiconductor region by implanting impurities of P-type conductivity from the rear surface of the substrate,
- wherein a density per unit volume of phosphorus in the second semiconductor region is at most ⅕ of a density of the impurities of the P-type conductivity in the buffer layer.
Dependencies are inferred from the claim text.