# US 10,118,250 B1 · In-situ laser beam position and spot size sensor and high speed scanner calibration, wafer debonding method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,118,250 B1 - Document ID: US10118250B1 - Status: Granted - Kind: B1 - Application number: 15/705,521 - Filed: 2017-09-15 - Granted: 2018-11-06 - Earliest claimed: 2017-09-15 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Russell Budd; Robert Polastre; Paul Andry - Web page: https://patentgrep.com/patent/US10118250B1 ## CPC - B23K 26/043: {along the beam path, i.e. alignment of laser beam axis relative to laser beam apparatus} - B23K 26/03: Observing, e.g. monitoring, the workpiece - B23K 26/0344: {Observing the speed of the workpiece} - B23K 26/0622: by shaping pulses - B23K 26/082: Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head - B23K 26/083: {Devices involving movement of the workpiece in at least one axial direction} - B23K 26/361: for deburring or mechanical trimming (B23K26/351 takes precedence) - B23K 26/402: involving non-metallic material, e.g. isolators - G01B 11/26: for measuring angles or tapers; for testing the alignment of axes - H10P 72/0428: {Apparatus for mechanical treatment or grinding or cutting} - H10P 72/74: {using temporarily an auxiliary support} - H10P 90/00: Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement - B23K 2101/40: Semiconductor devices - B23K 2103/172: {wherein at least one of the layers is non-metallic} - B23K 2103/42: {Plastics other than composite materials} - B23K 2103/56: {being semiconducting} - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - 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 - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM ## Abstract A method and system for aligning a scan laser beam on a wafer include scanning a scan laser beam across a laser beam sensor along a scan line, picking up a scan laser beam, at a first position, using a first optical slit of the laser beam sensor to generate a first electrical pulse, picking up the scan laser beam, at a second position, using a second optical slit of the laser beam sensor to generate a second electrical pulse, picking up the scan laser beam, at a third position, using a third optical slit of the laser beam sensor to generate a third electrical pulse, and determining a spot size and a position of the laser beam based on the first to third electrical pulses. ## Claims ### Claim 1 A laser beam sensing system comprising one or more laser beam sensors located outside a wafer and at least one processor, wherein at least one laser beam sensor of the laser beam sensors comprises, the at least one laser beam sensor being adjacent to one of opposing edges of the wafer: a first optical slit configured to pick up, at a first position of a laser scan line, a scan laser beam generated from a laser scanning system and guide the laser beam to a photodetector; a second optical slit configured to pick up, at a second position of the laser scan line, the scan laser beam and guide the laser beam to the photodetector; a third optical slit configured to pick up, at a third position of the laser scan line, the scan laser beam and guide the laser beam to the photodetector; and the photodetector configured to convert the laser beam guided through the first to third optical slits to first to third electrical pulses, respectively, wherein the at least one processor is configured to determine a spot size of the laser beam based on a laser scan speed and a temporal width of the first electrical pulse and determine a position of the scan laser beam based on a time difference between the second and third electrical pulses, and wherein positions of the second optical slit and the third optical slit relative to the wafer are known to the at least one processor. ### Claim 2 (depends on 1) The laser beam sensing system of claim 1, wherein the first optical slit is positioned between the second optical slit and the third optical slit. ### Claim 3 (depends on 1) The laser beam sensing system of claim 1, wherein each of the first to third optical slits is formed along a same plane as a top surface of the wafer. ### Claim 4 (depends on 1) The laser beam sensing system of claim 1, wherein the first optical slit has a first longitudinal direction substantially perpendicular to the laser scan line, and wherein the second optical slit has a second longitudinal direction oblique to the laser scan line, the third optical slit has a third longitudinal direction oblique to the laser scan line, and the second and third optical slits form a V-shape with respect to the first optical slit. ### Claim 5 (depends on 1) The laser beam sensing system of claim 1, wherein the at least one processor is configured to calibrate the laser scanning system based on the determined position of the scan laser beam. ### Claim 6 (depends on 1) The laser beam sensing system of claim 1, further comprising another laser beam sensor adjacent to another of the opposing edges of the wafer, said another laser beam sensor having a fourth optical slit configured to pick up, at a fourth position of the laser scan line, the scan laser beam and guide the laser beam to the photodetector, wherein the photodetector is configured to convert the laser beam guided through the fourth optical slit to a fourth electrical pulse, wherein the at least one processor is configured to determine whether a scan magnification of the laser scanning system is correct based on the time difference between the first electrical pulse and the fourth electrical pulse, the laser scan speed, and a predetermined distance between the first optical slit and the fourth optical slit. ### Claim 7 (depends on 6) The laser beam sensing system of claim 6, wherein responsive to determining that the scan magnification is not correct, the at least one processor is configured to adjust at least one of: a distance between a scan lens of the laser scanning system and the wafer; and on/off timing of the scan laser beam. ### Claim 8 A wafer debonding apparatus, comprising: a laser scanning system configured to provide a scan laser beam; a laser beam sensing system located outside a wafer for aligning the scan laser beam on the wafer, wherein at least one laser beam sensor of the laser beam sensing system comprises, the at least one laser beam sensor being adjacent to one of opposing edges of the wafer: a first optical slit configured to pick up, at a first position of a laser scan line, the scan laser beam and guide the laser beam to a photodetector; a second optical slit configured to pick up, at a second position of the laser scan line, the scan laser beam and guide the laser beam to the photodetector; a third optical slit configured to pick up, at a third position of the laser scan line, the scan laser beam and guide the laser beam to the photodetector; the photodetector configured to convert the laser beam guided through the first to third optical slits to first to third electrical pulses, respectively; and at least one processor configured to determine a spot size of the scan laser beam based on a laser scan speed and a temporal width of the first electrical pulse and determine a position of the scan laser beam based on a time difference between the second and third electrical pulses, and wherein positions of the second optical slit and the third optical slit relative to the wafer are known to the at least one processor. ### Claim 9 (depends on 8) The wafer debonding apparatus of claim 8, further comprising another laser beam sensor adjacent to another of the opposing edges of the wafer, said another laser beam sensor having a fourth optical slit configured to pick up, at a fourth position of the laser scan line, the scan laser beam and guide the laser beam to the photodetector, wherein the photodetector is configured to convert the laser beam guided through the fourth optical slit to a fourth electrical pulse, wherein the at least one processor is configured to determine whether a scan magnification of the laser scanning system is correct based on the time difference between the first electrical pulse and the fourth electrical pulse, the laser scan speed, and a predetermined distance between the first optical slit and the fourth optical slit. ### Claim 10 (depends on 8) The wafer debonding apparatus of claim 8, wherein responsive to determining that the scan magnification is not correct, the at least one processor is configured to adjust at least one of: a distance between a scan lens of the laser scanning system and the wafer; and on/off timing of the scan laser beam. ### Claim 11 (depends on 8) The wafer debonding apparatus of claim 8, wherein each of the first to third optical slits is formed along a same plane as a top surface of the wafer. ### Claim 12 (depends on 8) The wafer debonding apparatus of claim 8, wherein the first optical slit has a first longitudinal direction substantially perpendicular to the laser scan line, and wherein the second optical slit has a second longitudinal direction oblique to the laser scan line, the third optical slit has a third longitudinal direction oblique to the laser scan line, and the second and third optical slits form a V-shape with respect to the first optical slit. ### Claim 13 (depends on 8) The wafer debonding apparatus of claim 8, wherein the at least one processor is configured to calibrate the laser scanning system based on the determined position of the scan laser beam.