# US 2021/0082983 A1 · Image sensor formed in sequential 3d technology > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0082983 A1 - Document ID: US20210082983A1 - Status: Published application - Kind: A1 - Application number: 17/017,363 - Filed: 2020-09-10 - Published: 2021-03-18 - Earliest claimed: 2019-09-18 - Assignees: Commissariat A L'energie Atomique Et Aux Energies Alternatives - Applicants: Commissariat à l'Énergie Atomique et aux Énergies Alternatives - Inventors: Lina Kadura; François Andrieu; Perrine Batude; Christophe Licitra - Web page: https://patentgrep.com/patent/US20210082983A1 ## CPC - H10F 39/8057: {Optical shielding} - H10F 39/014: {of CMOS image sensors} - H10F 39/018: {of hybrid image sensors} - H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors - H10F 39/199: {Back-illuminated image sensors} - H10F 39/8037: {the integrated elements comprising a transistor} - H10F 39/805: {Coatings} - H10F 39/809: {of hybrid image sensors} - H10F 39/811: {Interconnections} - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract An image sensor including a plurality of pixels, each pixel including a photodetector coupled to a control circuit, the photodetector being formed inside and on top of a first semiconductor substrate, and the control circuit including at least one first MOS transistor formed inside and on top of a second semiconductor substrate arranged on the first substrate, the sensor being intended to be illuminated on the side of the surface of the first substrate opposite to the second substrate, the sensor further comprising a shield arranged between the first and second substrates and extending over substantially the entire surface of the sensor, said shield including at least one electrically-conductive layer. ## Claims ### Claim 1 An image sensor comprising a plurality of pixels, each pixel comprising a photodetector and a circuit for controlling the photodetector, the photodetector being formed inside and on top of a first semiconductor substrate, and the control circuit comprising at least one first MOS transistor formed inside and on top of a second semiconductor substrate arranged on the first substrate, the sensor being intended to be illuminated on the side of the surface of the first substrate opposite to the second substrate, the sensor further comprising a shield arranged between the first and second substrates and extending over substantially the entire surface of the sensor, said shield comprising at least one electrically-conductive layer. ### Claim 2 (depends on 1) The sensor according to claim 1, wherein said at least one electrically-conductive layer of the shield is made of metal or of a doped semiconductor material. ### Claim 3 (depends on 2) The sensor according to claim 2, wherein said at least one electrically-conductive layer of the shield is made of a germanium-containing semiconductor material. ### Claim 4 (depends on 3) The sensor according to claim 3, wherein said at least one electrically-conductive layer of the shield is made of a germanium-tellurium alloy. ### Claim 5 (depends on 2) The sensor according to claim 2, wherein said at least one electrically-conductive layer of the shield is made of a metal from the group comprising tungsten, aluminum, and titanium nitride. ### Claim 6 (depends on 1) The sensor according to claim 1, wherein the shield is absorbing in a detection wavelength range of the sensor. ### Claim 7 (depends on 1) The sensor according to claim 1, wherein the shield comprises an alternation of silicon oxide layers and of doped silicon layers forming a Bragg mirror reflecting the light transmitted by the first substrate at the detection wavelengths of the sensor. ### Claim 8 (depends on 1) The sensor according to claim 1, wherein the first and second substrates are made of silicon. ### Claim 9 (depends on 1) The sensor according to claim 1, wherein the shield is separated from the second substrate by an insulating layer. ### Claim 10 (depends on 1) The sensor according to claim 1, wherein said at least one conductive layer of the shield is connected to a node of application of a bias potential via a conductive via crossing the second substrate. ### Claim 11 (depends on 1) The sensor according to claim 1, wherein each pixel comprises a conductive via crossing the second substrate and the shield, said via coupling the photodetector to said at least one first MOS transistor. ### Claim 12 (depends on 11) The sensor according to claim 11, wherein said conductive via has a diameter smaller than or equal to 90 nm. ### Claim 13 (depends on 1) The sensor according to claim 1, wherein the control circuit comprises at least one second MOS transistor formed inside and on top of the first substrate, and wherein the gate of said at least one second MOS transistor is arranged on the side of a surface of the first substrate facing the second substrate, the gate of said at least one first transistor being arranged on the side of a surface of the second substrate opposite to the first substrate. ### Claim 14 (depends on 1) The sensor of claim 1, wherein the distance between the first and second substrates is shorter than or equal to 750 nm. ### Claim 15 (depends on 1) The sensor according to claim 1, comprising no metal interconnection tracks parallel to the first and second substrates between the first substrate and the shield. ### Claim 16 (depends on 1) The sensor according to claim 1, wherein the pixels of said plurality of pixels are arranged in an array. ### Claim 17 A method of manufacturing an image sensor comprising a plurality of pixels, each pixel comprising a photodetector and a circuit for controlling the photodetector, the photodetector being formed inside and on top of a first semiconductor substrate, and the control circuit comprising at least one first MOS transistor formed inside and on top of a second semiconductor substrate arranged on the first substrate, the sensor being intended to be illuminated on the side of the surface of the first substrate opposite to the second substrate, the sensor further comprising a shield arranged between the first and second substrates and extending over substantially the entire surface of the sensor, said shield comprising at least one electrically-conductive layer, the method comprising the successive steps of: forming the photodetector in the first substrate; depositing the shield on the first substrate or on the second substrate; transferring the second substrate onto the first substrate so that the screen is arranged between the first and second substrates; and forming said at least one first MOS transistor inside and on top of the second substrate, on the side of a surface of the second substrate opposite to the shield.