# US 2014/0197513 A1 · Image Sensor with Improved Dark Current Performance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0197513 A1 - Document ID: US20140197513A1 - Status: Published application - Kind: A1 - Application number: 14/225,509 - Filed: 2014-03-26 - Published: 2014-07-17 - Earliest claimed: 2011-11-14 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufacturing Company Ltd. - Inventors: Wei-Chih Weng; Hsun-Ying Huang; Yung-Cheng Chang; Jin-Hong Cho - Web page: https://patentgrep.com/patent/US20140197513A1 ## CPC - H10F 39/8057: {Optical shielding} - H10F 39/024: {of coatings or optical elements} - H10F 39/199: {Back-illuminated image sensors} - H10F 39/805: {Coatings} - H10F 39/811: {Interconnections} - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract Provided is a semiconductor image sensor device. The image sensor device includes a semiconductor substrate that includes an array region and a black level correction region. The array region contains a plurality of radiation-sensitive pixels. The black level correction region contains one or more reference pixels. The substrate has a front side and a back side. The image sensor device includes a first compressively-stressed layer formed on the back side of the substrate. The first compressively-stressed layer contains silicon nitride. The image sensor device includes a metal shield formed on the compressively-stressed layer. The metal shield is formed over at least a portion of the black level correction region. The image sensor device includes a second compressively-stressed layer formed on the metal shield and the first compressively-stressed layer. The second compressively-stressed layer contains silicon oxide. A sidewall of the metal shield is protected by the second compressively-stressed layer. ## Claims ### Claim 1 A method of fabricating a semiconductor image sensor device, comprising: forming a plurality of radiation-sensing components in a semiconductor substrate, the substrate including a black level correction region; forming a first compressive layer over the substrate; forming a metal device on the first compressive layer, the metal device being formed over the black level correction region of the substrate; and forming a second compressive layer on the metal device and on the first compressive layer. ### Claim 2 (depends on 1) The method of claim 1, wherein: the substrate has a front surface and a back surface; the radiation-sensing components are operable to sense light that enters the substrate from the back surface; and the first compressive layer is formed over the back surface of the substrate. ### Claim 3 (depends on 1) The method of claim 1, wherein the black level correction region contains one or more reference pixels. ### Claim 4 (depends on 1) The method of claim 1, wherein the metal device is a tensile device. ### Claim 5 (depends on 1) The method of claim 1, wherein: the first compressive layer contains silicon nitride; and the second compressive layer contains silicon oxide. ### Claim 6 (depends on 1) The method of claim 1, wherein a portion of the second compressive layer is formed on a sidewall of the metal device. ### Claim 7 A method of fabricating a semiconductor device, comprising: providing a substrate having a front side and a back side, the substrate having radiation-sensing elements disposed in a first region of the substrate; thinning the substrate from the back side; forming a first compressive layer over the back side of the substrate; forming a light shield over a selected portion of the first compressive layer; and forming a second compressive layer over the first compressive layer and over the light shield. ### Claim 8 (depends on 7) The method of claim 7, wherein the forming of the light shield comprises forming a metal device as the light shield. ### Claim 9 (depends on 7) The method of claim 7, wherein the forming of the light shield is performed so that the light shield is formed over a second region of the substrate that needs to be kept optically dark. ### Claim 10 (depends on 9) The method of claim 9, wherein the second region of the substrate contains one or more reference pixels. ### Claim 11 (depends on 7) The method of claim 7, wherein the forming of the light shield comprises forming a tensile device as the light shield. ### Claim 12 (depends on 7) The method of claim 7, wherein: the forming of the first compressive layer comprises forming silicon nitride as the first compressive layer; and the forming of the second compressive layer comprises forming silicon oxide as the second compressive layer. ### Claim 13 (depends on 7) The method of claim 7, wherein the forming of the second compressive layer is performed such that a portion of the second compressive layer comes into direct contact with a sidewall of the light shield. ### Claim 14 (depends on 7) The method of claim 7, further comprising: before the thinning, bonding the front side of the substrate to a carrier substrate. ### Claim 15 (depends on 7) The method of claim 7, further comprising: before the forming of the first compressive layer, forming a third compressive layer over the back side of the substrate, wherein the first compressive layer is formed on the third compressive layer; and after the forming of the second compressive layer, forming a fourth compressive layer on the second compressive layer. ### Claim 16 A semiconductor image sensor device, comprising: a semiconductor substrate having a front side and a back side, the substrate including an array region and a black level correction region, wherein the array region contains a plurality of radiation-sensitive pixels proximate the front side, and the black level correction region contains one or more reference pixels proximate the front side; a first compressively-stressed layer formed on the back side of the substrate, the first compressively-stressed layer containing silicon nitride; a metal shield formed on the compressively-stressed layer, wherein the metal shield is formed over at least a portion of the black level correction region; and a second compressively-stressed layer formed on the metal shield and the first compressively-stressed layer, wherein the second compressively-stressed layer contains silicon oxide, and wherein a sidewall of the metal shield is protected by the second compressively-stressed layer. ### Claim 17 (depends on 16) The image sensor device of claim 16, wherein the radiation-sensitive pixels are configured to detect light that enters the substrate from the back side. ### Claim 18 (depends on 16) The image sensor device of claim 16, wherein the metal shield is a tensile device. ### Claim 19 (depends on 16) The image sensor device of claim 16, further including: a third compressively-stressed layer formed between the substrate and the first compressively-stressed layer; and a fourth compressively-stressed layer formed on the second compressively-stressed layer. ### Claim 20 (depends on 19) The image sensor device of claim 19, wherein: the third compressively-stressed layer contains an oxide material; and the fourth compressively-stressed layer contains a nitride material.