# US 2018/0026066 A1 · Back-side illuminated (bsi) image sensor with global shutter scheme > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026066 A1 - Document ID: US20180026066A1 - Status: Published application - Kind: A1 - Application number: 15/710,419 - Filed: 2017-09-20 - Published: 2018-01-25 - Earliest claimed: 2015-10-26 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufacturing Co., Ltd. - Inventors: Chun-Yuan Chen; Ching-Chun Wang; Dun-Nian Yaung; Shyh-Fann Ting; Wei Chuang Wu; Yen-Ting Chiang; Kuan-Tsun Chen - Web page: https://patentgrep.com/patent/US20180026066A1 ## CPC - H10F 39/8067: {Reflectors} - H10F 39/014: {of CMOS image sensors} - H10F 39/024: {of coatings or optical elements} - H10F 39/182: {Colour image sensors} - H10F 39/199: {Back-illuminated image sensors} - H10F 39/8057: {Optical shielding} - H10F 39/811: {Interconnections} - H10F 39/803: {Pixels having integrated switching, control, storage or amplification elements} - H10F 39/8053: {Colour filters} - H10F 39/8063: {Microlenses} - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract In some embodiments, the present disclosure relates to a method of forming a back-side image (BSI) sensor. The method may be performed by forming an image sensing element within a substrate and forming a pixel-level memory node at a position within the substrate that is laterally offset from the image sensing element. A back-side of the substrate is etched to form one or more trenches that are laterally separated from the image sensing element by the substrate and that vertically overlie the pixel-level memory node. A reflective material is formed within the one or more trenches. ## Claims ### Claim 1 A method of forming a back-side illuminated (BSI) image sensor, comprising: forming an image sensing element within a substrate; forming a pixel-level memory node at a position within the substrate that is laterally offset from the image sensing element; etching a back-side of the substrate to form one or more trenches that are laterally separated from the image sensing element by the substrate and that vertically overlie the pixel-level memory node; and forming a reflective material within the one or more trenches. ### Claim 2 (depends on 1) The method of claim 1, further comprising: performing a planarization process to remove a part of the reflective material outside of the one or more trenches. ### Claim 3 (depends on 1) The method of claim 1, further comprising: forming a plurality of metal interconnect layers within a dielectric structure prior to etching the back-side of the substrate, wherein the dielectric structure is arranged along a front-side of the substrate opposing the back-side of the substrate. ### Claim 4 (depends on 3) The method of claim 3, further comprising: bonding the dielectric structure to a carrier substrate; and reducing a thickness of the substrate after bonding the dielectric structure to the carrier substrate. ### Claim 5 (depends on 1) The method of claim 1, wherein the reflective material comprises a metal. ### Claim 6 (depends on 1) The method of claim 1, wherein the reflective material is deposited by way of a deposition process and a plating process. ### Claim 7 (depends on 1) The method of claim 1, wherein the reflective material comprises a multi-layer reflective film formed by a series of deposition processes. ### Claim 8 (depends on 1) The method of claim 1, further comprising: forming a passivation layer onto the back-side of the substrate and onto the reflective material. ### Claim 9 (depends on 1) The method of claim 1, wherein the reflective material extends from the substrate to a horizontal plane extending along the back-side of the substrate. ### Claim 10 (depends on 1) The method of claim 1, wherein the reflective material is separated from the image sensing element by the substrate. ### Claim 11 A method of forming an image sensor, comprising: forming an image sensing element within a substrate forming a memory node within the substrate, wherein the memory node is laterally separated from the image sensing element; forming a masking layer along a back-side of the substrate over the image sensing element; etching the back-side of the substrate according to the masking layer to define one or more trenches directly between the memory node and a horizontal plane extending along the back-side of the substrate; and forming a reflective material within the one or more trenches. ### Claim 12 (depends on 11) The method of claim 11, further comprising: forming an inter-level dielectric (ILD) layer along a front-side of the substrate facing an opposite direction as the back-side of the substrate; patterning the ILD layer to define an opening within the ILD layer; and forming a conductive material within the opening. ### Claim 13 (depends on 11) The method of claim 11, wherein the memory node is separated from the reflective material by the substrate. ### Claim 14 (depends on 11) The method of claim 11, wherein the reflective material comprises copper or aluminum. ### Claim 15 (depends on 11) The method of claim 11, further comprising: forming a passivation layer contacting the back-side of the substrate and the reflective material. ### Claim 16 (depends on 11) The method of claim 11, wherein the reflective material completely fills the one or more trenches from the substrate to the horizontal plane extending along the back-side of the substrate. ### Claim 17 (depends on 11) The method of claim 11, wherein the reflective material is laterally separated from the image sensing element by the substrate. ### Claim 18 A method of forming a back-side illuminated (BSI) image sensor, comprising: forming an image sensing element within a substrate; forming a memory node at a position within the substrate separated from the image sensing element; forming a dielectric structure surrounding one or more interconnect layers on a first side of the substrate; and forming a reflective material along a second side of the substrate facing an opposite direction as the first side, wherein the reflective material has sidewalls defining an aperture that is directly over the image sensing element. ### Claim 19 (depends on 18) The method of claim 18, further comprising: etching the second side of the substrate to form one or more trenches that are laterally separated from the image sensing element by the substrate and that are vertically between the memory node and a horizontal plane extending along the second side of the substrate; and forming the reflective material within the one or more trenches. ### Claim 20 (depends on 19) The method of claim 19, wherein the reflective material extends from the substrate to the horizontal plane extending along the second side of the substrate.