# US 2022/0285218 A1 · Laser lift-off method for separating substrate and semiconductor-epitaxial structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0285218 A1 - Document ID: US20220285218A1 - Status: Published application - Kind: A1 - Application number: 17/194,100 - Filed: 2021-03-05 - Published: 2022-09-08 - Earliest claimed: 2021-03-05 - Assignees: Sky Tech Inc. - Applicants: Sky Tech Inc. - Inventors: JING-CHENG LIN; TSUNG-HUA HSIEH - Web page: https://patentgrep.com/patent/US20220285218A1 ## CPC - H10P 95/112: {leaving a reusable substrate, e.g. epitaxial lift off} - B23K 26/08: Devices involving relative movement between laser beam and workpiece - B23K 26/16: Removal of by-products, e.g. particles or vapours produced during treatment of a workpiece (by a fluid stream B23K26/142) - B23K 26/402: involving non-metallic material, e.g. isolators - B23K 26/50: Working by transmitting the laser beam through or within the workpiece - H10P 72/0428: {Apparatus for mechanical treatment or grinding or cutting} - B32B 43/006: {Delaminating} - Y10T 156/1158: Electromagnetic radiation applied to work for delamination [e.g., microwave, uv, ir, etc.] - Y10T 156/1917: Electromagnetic radiation delaminating means [e.g., microwave, uv, ir, etc.] - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present disclosure provides a laser lift-off method for separating substrate and semiconductor-epitaxial structure, which includes: providing at least one semiconductor device, wherein the semiconductor device includes a substrate and at least one semiconductor-epitaxial structure disposed in a stack-up manner; irradiating a laser onto an edge area of the semiconductor device to separate portions of the substrate and the semiconductor-epitaxial structure in the edge area; and pressing against the edge area of the semiconductor device vis a pressing device, then irradiating the laser onto an inner area of the semiconductor device to separate portions of the substrate and the semiconductor-epitaxial structure in the inner area wherein gas is generated during separating the portions of the substrate and the semiconductor-epitaxial structure in the inner area and evacuated from the edge area, to prevent damage of the semiconductor-epitaxial structure during the separating process. ## Claims ### Claim 1 A laser lift-off method for separating substrate and semiconductor-epitaxial structure, comprising: providing at least one semiconductor device, wherein the at least one semiconductor device comprises a substrate and at least one semiconductor-epitaxial structure, and the at least one semiconductor-epitaxial structure is connected to the substrate; irradiating a laser onto an edge area of the at least one semiconductor device, wherein a light of the laser is projected on a side of the at least one semiconductor-epitaxial structure that is connected to the substrate to separate the substrate and the at least one semiconductor-epitaxial structure in the edge area; pressing the edge area of the at least one semiconductor device via a pressing device; and irradiating the laser onto an inner area of the at least one semiconductor device, the light of the laser is projected on the side of the at least one semiconductor-epitaxial structure that is connected to the substrate to separate the substrate and the at least one semiconductor-epitaxial structure in the inner area. ### Claim 2 (depends on 1) The laser lift-off method according to claim 1, wherein the light of the laser is projected on the side of the at least one semiconductor-epitaxial structure that is connected to the substrate, to separate the substrate and the at least one semiconductor-epitaxial structure in the edge area, thereby the at least one semiconductor-epitaxial structure absorbs an energy from the laser and starts thermal decomposition then to produce gas, and the gas is evacuated from a lateral side of the at least one semiconductor device. ### Claim 3 (depends on 1) The laser lift-off method according to claim 1, further comprising: placing the at least one semiconductor device on a suction platform that creates a negative pressure for sucking and fastening the at least one semiconductor device; and operating the light of the laser to enter the at least one semiconductor device from the substrate to irradiate onto the edge area of the at least one semiconductor device and to be projected on the side of the at least one semiconductor-epitaxial structure that is connected to the substrate, thereby to allow the at least one semiconductor-epitaxial structure absorb an energy from the laser and start thermal decomposition. ### Claim 4 (depends on 3) The laser lift-off method according to claim 3, wherein the suction platform comprises a plurality of suction holes for creating a negative pressure for fastening the at least one semiconductor device. ### Claim 5 (depends on 1) The laser lift-off method according to claim 1, further comprising: operating the laser to irradiate onto and process the edge area of the at least one semiconductor device to form a processed zone, until a width of the processed zone exceeds a threshold value; and temporarily stopping the laser from processing the at least one semiconductor device, and using the pressing device to press against the edge area of the at least one semiconductor device, thereafter to irradiate the laser onto and process the inner area of the at least one semiconductor device. ### Claim 6 (depends on 5) The laser lift-off method according to claim 5, wherein the threshold value is equal to or greater than 1.5 mm. ### Claim 7 (depends on 1) The laser lift-off method according to claim 1, wherein the pressing device comprises a plurality of pressing units for pressing against the edge area of the at least one semiconductor device, and each adjacent two of the pressing units have a gap therebetween. ### Claim 8 (depends on 1) The laser lift-off method according to claim 1, wherein the pressing device is formed in an annular shape, and disposed to move related to the suction platform in an up-down direction for pressing the at least one semiconductor device on the suction platform. ### Claim 9 (depends on 1) The laser lift-off method according to claim 1, wherein the at least one semiconductor-epitaxial structure is a gallium-nitride-compound epitaxial structure or a gallium-nitride epitaxial structure. ### Claim 10 (depends on 1) The laser lift-off method according to claim 1, comprising a step of connecting the at least one semiconductor-epitaxial structure of the at least one semiconductor device to an alternative substrate, before irradiating the laser onto the at least one semiconductor device. ### Claim 11 A laser lift-off method for separating substrate and semiconductor-epitaxial structure, comprising: providing at least one semiconductor device, wherein the at least one semiconductor device comprises a substrate and at least one semiconductor-epitaxial structure, and the at least one semiconductor-epitaxial structure is connected to the substrate; irradiating a laser onto and processing the at least one semiconductor device and move the laser along a lateral side of the at least one semiconductor device, to separate the substrate and the at least one semiconductor-epitaxial structure in the lateral side and to form a first separate zone in the lateral side of the at least one semiconductor device; moving the laser toward a radially-inner side of the first separate zone; moving the laser along an inner periphery of the first separate zone to form at least one second separate zone, wherein the at least one second separate zone is adjacent to the first separate zone and in the radially-inner side of the first separate zone; pressing against the first separate zone and the at least one second separate zone of the at least one semiconductor device via a pressing device; and irradiating the laser onto and processing an inner area of the at least one semiconductor device, a light of the laser is projected on a side of the at least one semiconductor-epitaxial structure that is connected to the substrate to separate the substrate and the at least one semiconductor-epitaxial structure in the inner area, wherein the at least one second separate zone surrounds the inner area. ### Claim 12 (depends on 11) The laser lift-off method according to claim 11, comprising of a step of placing the at least one semiconductor device on a suction platform that creates a negative pressure for sucking and fastening the at least one semiconductor device. ### Claim 13 (depends on 12) The laser lift-off method according to claim 12, wherein the suction platform comprises a plurality of suction holes for creating a negative pressure to fasten the at least one semiconductor device. ### Claim 14 (depends on 11) The laser lift-off method according to claim 11, comprising a step of operating the light of the laser to enter the at least one semiconductor device from the substrate and projecting the light of the laser on the side of the at least one semiconductor-epitaxial structure that is connected to the substrate, when processing and forming the first separate zone and the at least one second separate zone of the at least one semiconductor device, thereby to allow the at least one semiconductor-epitaxial structure absorb an energy from the laser and start thermal decomposition then to produce gas, and then the gas is evacuated from the lateral side of the at least one semiconductor device. ### Claim 15 (depends on 11) The laser lift-off method according to claim 11, wherein the pressing device comprises a plurality of pressing units for pressing against the first separate zone and the at least one second separate zone of the at least one semiconductor device, and each adjacent two of the pressing units have a space therebetween. ### Claim 16 (depends on 11) The laser lift-off method according to claim 11, wherein the pressing device is formed in an annular shape, and disposed to move related to the suction platform in an up-down direction for pressing the at least one semiconductor device on the suction platform. ### Claim 17 (depends on 11) The laser lift-off method according to claim 11, comprising: operating the laser to process and form the first separate zone and the at least one second separate zone of the at least one semiconductor device, until a summed value of a width of the first separate zone and a width of the at least one second separate zone exceeds a threshold value; and temporarily stopping the laser from processing the at least one semiconductor device, and using the pressing device to press against the first separate zone and the at least one second separate zone of the at least one semiconductor device, thereafter to continue processing the at least one semiconductor device with the laser. ### Claim 18 (depends on 11) The laser lift-off method according to claim 11, wherein the threshold value is equal to or greater than 1.5 mm. ### Claim 19 (depends on 11) The laser lift-off method according to claim 11, wherein a light spot size of the laser projected on the first separate zone is larger than that on the at least one second separate zone. ### Claim 20 (depends on 11) The laser lift-off method according to claim 11, comprising a step of connecting the at least one semiconductor-epitaxial structure of the at least one semiconductor device to an alternative substrate, before irradiating the laser onto and processing the at least one semiconductor device.