# US 10,455,176 B2 · Image sensor and image capturing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,455,176 B2 - Document ID: US10455176B2 - Status: Granted - Kind: B2 - Application number: 15/747,001 - Filed: 2016-07-07 - Published: 2018-08-02 - Granted: 2019-10-22 - Earliest claimed: 2015-08-11 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Hideki Ikedo - Web page: https://patentgrep.com/patent/US10455176B2 ## CPC - H04N 25/76: Addressed sensors, e.g. MOS or CMOS sensors - G02B 27/0025: {for optical correction, e.g. distorsion, aberration} - H04N 23/54: Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils - H04N 25/61: the noise originating only from the lens unit, e.g. flare, shading, vignetting or "cos4" - H04N 25/63: applied to dark current - H10F 39/014: {of CMOS image sensors} - H10F 39/8023: {Disposition of the elements in pixels, e.g. smaller elements in the centre of the imager compared to larger elements at the periphery} - H10F 39/8027: {Geometry of the photosensitive area} - H10F 39/8033: {Photosensitive area} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract An image sensor in which at least a portion of an imaging plane thereof has a curved shape, wherein the imaging plane includes a plurality of pixels that are two-dimensionally arranged, each of the plurality of pixels having: a photoelectric conversion region that is provided with an impurity region of a first conductivity type that is formed in a semiconductor substrate; and an impurity region of a second conductivity type that is formed on a substrate surface side of the photoelectric conversion region, and impurity concentration in the impurity region of the second conductivity type varies depending on a position on the imaging plane. ## Claims ### Claim 1 An image sensor in which at least a portion of an imaging plane thereof has a curved shape, wherein the imaging plane includes a plurality of pixels that are two-dimensionally arranged, each of the plurality of pixels having: a photoelectric conversion region that is provided with an impurity region of a first conductivity type that is formed in a semiconductor substrate; and an impurity region of a second conductivity type that is formed on a substrate surface side of the photoelectric conversion region, and impurity concentration in the impurity region of the second conductivity type varies depending on a position on the imaging plane and a relative dark current amount in the corresponding photoelectric conversion region. ### Claim 2 (depends on 1) The image sensor according to claim 1, wherein curvature of the imaging plane varies depending on a position on the imaging plane, and the impurity concentration in the impurity region of the second conductivity type varies depending on the curvature of the imaging plane. ### Claim 3 (depends on 2) The image sensor according to claim 2, wherein the impurity concentration in the impurity region of the second conductivity type is higher in a region of the imaging plane in which the curvature of the imaging plane is smaller. ### Claim 4 (depends on 1) The image sensor according to claim 1, wherein stress generated in the imaging plane varies depending on a position on the imaging plane, and the impurity concentration in the impurity region of the second conductivity type varies depending on the stress generated in the imaging plane. ### Claim 5 (depends on 4) The image sensor according to claim 4, wherein the impurity concentration in the impurity region of the second conductivity type is higher in a region of the imaging plane in which the stress that is generated is smaller. ### Claim 6 (depends on 1) The image sensor according to claim 1, wherein the impurity concentration in the impurity region of the second conductivity type is higher in a region where the relative dark current amount in the corresponding photoelectric conversion region is greater. ### Claim 7 (depends on 1) The image sensor according to claim 1, wherein the impurity region of the second conductivity type is formed by implanting an impurity of the second conductivity type by performing ion implantation a plurality of times for each of the plurality of pixels. ### Claim 8 (depends on 1) The image sensor according to claim 1, wherein the impurity region of the second conductivity type is formed by implanting an impurity of the second conductivity type by performing ion implantation through a resist pattern provided with apertures arranged at regular intervals, for each of the plurality of pixels. ### Claim 9 (depends on 8) The image sensor according to claim 8, wherein an aperture ratio of the apertures arranged at the regular intervals is greater in a region in which the impurity concentration in the corresponding impurity region of the second type is higher. ### Claim 10 (depends on 1) The image sensor according to claim 1, wherein an electrode that partially overlaps the photoelectric conversion region is formed above the semiconductor substrate. ### Claim 11 (depends on 1) The image sensor according to claim 1, wherein the imaging plane includes a peripheral portion having a curved shape and a flat portion located in a central region of the imaging plane, and the impurity concentration in the impurity region of a pixel in the flat portion is higher than the impurity concentration of the impurity region of a pixel in the peripheral portion. ### Claim 12 (depends on 11) The image sensor according to claim 11, wherein the curved shape is a spherical shape, and the impurity concentration in the impurity region of a pixel in a peripheral portion of the imaging plane is higher than the impurity concentration of the impurity region of a pixel in the central region. ### Claim 13 An image capturing apparatus comprising: an image sensor in which at least a portion of an imaging plane thereof has a curved shape, wherein the imaging plane includes a plurality of pixels that are two-dimensionally arranged, each of the plurality of pixels having a photoelectric conversion region that is provided with an impurity region of a first conductivity type that is formed in a semiconductor substrate and an impurity region of a second conductivity type that is formed on a substrate surface side of the photoelectric conversion region, and impurity concentration in the impurity region of the second conductivity type varies depending on a position on the imaging plane and a relative dark current amount in the corresponding photoelectric conversion region; and a sensitivity correction circuit that corrects sensitivity for each pixel region of the image sensor. ### Claim 14 (depends on 13) The apparatus according to claim 13, wherein the sensitivity correction circuit corrects spectral sensitivity according to the impurity concentration in the impurity region of each of the plurality of pixels.