WO2022215388A1 - レーザ加工方法及びレーザ加工装置 - Google Patents
レーザ加工方法及びレーザ加工装置 Download PDFInfo
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- WO2022215388A1 WO2022215388A1 PCT/JP2022/008694 JP2022008694W WO2022215388A1 WO 2022215388 A1 WO2022215388 A1 WO 2022215388A1 JP 2022008694 W JP2022008694 W JP 2022008694W WO 2022215388 A1 WO2022215388 A1 WO 2022215388A1
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- laser
- laser beam
- irradiation
- irradiated
- grooving
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/50—Working by transmitting the laser beam through or within the workpiece
- B23K26/53—Working by transmitting the laser beam through or within the workpiece for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/073—Shaping the laser spot
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/352—Working by laser beam, e.g. welding, cutting or boring for surface treatment
- B23K26/354—Working by laser beam, e.g. welding, cutting or boring for surface treatment by melting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/60—Preliminary treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/268—Bombardment with radiation with high-energy radiation using electromagnetic radiation, e.g. laser radiation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/324—Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
- H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/36—Electric or electronic devices
- B23K2101/40—Semiconductor devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
- B23K2103/56—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26 semiconducting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/0006—Working by laser beam, e.g. welding, cutting or boring taking account of the properties of the material involved
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/03—Observing, e.g. monitoring, the workpiece
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- 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
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
- B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
Definitions
- One aspect of the present invention relates to a laser processing method and a laser processing apparatus.
- the wafer In order to cut a wafer including a semiconductor substrate and a functional element layer formed on one surface of the semiconductor substrate along a plurality of lines, the wafer is irradiated with a laser beam from the other surface side of the semiconductor substrate.
- a laser processing apparatus is known that forms a plurality of rows of modified layers inside a semiconductor substrate along each of a plurality of lines (see, for example, Patent Document 1).
- the laser beam irradiation surface of the object on which the modified layer is to be formed is not flat but rough, the laser beam may be absorbed or scattered on the irradiation surface. There is a possibility that a modified layer cannot be properly formed inside.
- One aspect of the present invention has been made in view of the above circumstances, and an object thereof is to appropriately flatten the irradiated surface of an object and appropriately form a modified layer inside the object.
- a laser processing method includes a first step of irradiating a front surface or a rear surface of an object having a functional element layer on the surface side with a first laser beam and planarizing the irradiated surface by laser annealing; and a second step of irradiating the irradiation surface planarized in the first step with a second laser beam to form a modified layer inside the object, wherein the pulse pitch of the first laser beam is the same as that of the second laser beam. shorter than the pulse pitch of light.
- the surface irradiated with the second laser beam is subjected to laser annealing.
- a first laser beam is applied to planarize the irradiated surface. If the surface irradiated with the laser light when forming the modified layer is rough and not flat, the modified layer may not be properly formed by irradiation with the laser light.
- the irradiation surface for forming the modified layer is irradiated in advance with the first laser beam for flattening the irradiation surface (laser annealing is is performed), it is possible to irradiate the flattened irradiation surface with the second laser beam, and to appropriately form a modified layer inside the object.
- the pulse pitch of the first laser light for laser annealing is shorter than the pulse pitch of the second laser light for forming the modified layer.
- the region that is recrystallized and flattened after melting is reduced. It can be formed continuously, and planarization of the irradiated surface by laser annealing can be more appropriately achieved.
- the laser processing method of the present invention it is possible to appropriately planarize the irradiation surface of the object and appropriately form the modified layer inside the object.
- the first laser beam and the second laser beam may be emitted from a common light source. According to such a configuration, the configuration related to laser processing can be simplified, and the size reduction of the device configuration can be realized.
- the frequency of the first laser light may be higher than the frequency of the second laser light.
- the next laser beam is irradiated before the irradiated area cools down, thereby accumulating heat and appropriately recrystallizing the irradiated area. .
- by increasing the frequency of the first laser light (making it higher than the frequency of the second laser light), it is possible to more appropriately flatten the irradiated surface by laser annealing.
- the number of branches in the processing progress direction of the first laser light may be greater than the number of branches in the processing progress direction of the second laser light. Since the number of branches of the first laser beam in the processing progress direction is large (more than the number of branches of the second laser beam), the time required for the laser annealing process can be shortened.
- the number of branches in the direction that intersects the processing progress direction of the first laser beam and is parallel to the irradiation surface is the direction that intersects the processing progress direction of the second laser beam, and the irradiation It may be more than the number of branches in the direction parallel to the plane.
- the irradiation ranges of the branched beams of the first laser light may partially overlap each other on the irradiation surface. Thereby, planarization can be performed even if the energy per point is low.
- unevenness occurs between the center of the beam and a location away from the center of the beam.
- the illuminated surface can be flattened.
- the first laser beam may be a top hat-shaped laser beam.
- the laser annealing region can be widened on the irradiation surface.
- the irradiation surface can be made flatter.
- the irradiation surface in the first step, may be irradiated with the first laser beam so as to planarize the irradiation surface and form a modified layer inside the object.
- the first laser light related to laser annealing for planarization also to form the modified layer for example, the number of passes of the second laser light related to the formation of the modified layer can be reduced, The time required for forming the modified layer can be shortened.
- the irradiated surface in the first step, may be irradiated with the first laser beam so as not to form a modified layer inside the object.
- the irradiated surface may be irradiated with the first laser beam so as not to form a modified layer inside the object.
- the focal point of the first laser beam may be positioned outside the object. As a result, it is possible to appropriately avoid formation of a modified layer inside the object due to laser light for laser annealing.
- the back surface in the first step, may be irradiated with the first laser beam to planarize the back surface.
- the back surface of the object may have, for example, a satin finish or may be rough.
- the laser beam is absorbed or scattered on the back surface, and a modified layer is appropriately formed inside the object. may not be possible.
- the roughened back surface can be appropriately flattened, and the modified layer can be appropriately formed inside the object.
- the above laser processing method further comprises a first grooving step of forming a weakened region on the front surface of the object by irradiating the third laser beam from the back surface of the object before the second step.
- the back surface may be planarized by irradiating the back surface before the process with the first laser beam as an irradiation surface.
- the weakened region is utilized by irradiating the rear surface with the second laser beam for forming the modified layer in the second step. , a crack reaching the surface side on which the functional element layer is formed can be appropriately formed.
- the first grooving step when performing the first grooving step, if there is damage to the back surface on which the third laser beam is incident, it is difficult to appropriately perform grooving (IR grooving) on the front surface side, and the third laser beam for grooving energy is limited.
- the first step relating to laser annealing is performed with the back surface as the irradiation surface, so that the first grooving step is performed with the back surface being flattened.
- the amount of energy that can be applied to the third laser beam in one grooving process increases, and the types of target objects (devices) that can be handled increase. Thereby, grooving (IR grooving) on the surface side can be performed more easily and appropriately.
- the laser processing method further comprises a second grooving step of removing the surface layer of the surface by irradiating the surface of the object with a fourth laser beam, and in the first step, the surface layer formed on the surface by the second grooving step.
- the bottom surface of the groove may be irradiated with the first laser beam using the bottom surface of the groove as an irradiation surface to planarize the bottom surface of the groove.
- the surface is irradiated with the second laser beam for forming the modified layer in the second step, thereby improving the processing throughput and processing quality such as film peeling. can be suppressed.
- the bottom surface of the grooves formed on the surface by grooving is rough. For this reason, normally, stealth dicing cannot be performed from the front surface after grooving, and the second laser beam for forming the modified layer is irradiated from the rear surface side after transferring to the rear surface side. In this case, the transfer cost is a problem.
- the bottom surface of the groove formed on the surface is flattened by performing the first step related to laser annealing with the bottom surface of the groove formed on the surface as the irradiation surface. , stealth dicing can be performed from the surface that is the grooving surface side, and the transfer process described above is not required. This makes it possible to speed up processing and reduce costs.
- a laser processing apparatus includes a support section that supports an object having a functional element layer on the surface side, an irradiation section that irradiates the object with laser light, and a first laser beam on the front surface or the back surface of the object.
- a second control that controls the irradiation unit so that the modified layer is formed inside the object by irradiation; and a control unit configured to perform a second control.
- the controller may control the irradiator so that in the first control, the back surface is irradiated with the first laser beam and the back surface is flattened.
- control unit controls the irradiation unit such that the weakened region is formed on the front surface of the object by irradiating the third laser beam from the rear surface of the object before the second control is performed. Control may be further performed, and in the first control, the irradiation unit may be controlled so that the back surface before the first grooving control is irradiated with the first laser light and the back surface is flattened.
- control unit further performs second grooving control for controlling the irradiation unit such that the surface layer of the surface is removed by irradiating the surface of the object with the fourth laser beam,
- the irradiation unit may be controlled so that the bottom surface of the groove formed on the surface by the second grooving control is irradiated with the first laser light and the bottom surface of the groove is flattened.
- FIG. 2 is a front view of a portion of the laser processing apparatus shown in FIG. 1;
- FIG. FIG. 2 is a front view of a laser processing head of the laser processing apparatus shown in FIG. 1;
- 4 is a side view of the laser processing head shown in FIG. 3;
- FIG. 4 is a configuration diagram of an optical system of the laser processing head shown in FIG. 3;
- FIG. It is a figure explaining the subject at the time of stealth dicing processing. It is a figure explaining the subject at the time of stealth dicing processing. It is a figure explaining the subject at the time of stealth dicing processing. It is a figure explaining the modification layer formation processing after planarization processing and planarization processing.
- FIG. 10 is a diagram showing laser annealing results for each laser beam condition shown in FIG. 9; It is a figure explaining the flatness improvement by a horizontal branch.
- FIG. 10 is a diagram for explaining tact-up and expansion of flattened width due to lateral branching; It is a figure explaining the effect of branching in the direction which intersects the direction of progress of processing. It is a figure which shows an example of laser annealing and modification layer formation for every condensing position. It is a figure which shows an example of GUI. It is a figure which shows an example of GUI.
- 4 is a flowchart showing a laser processing method including planarization processing and modified layer forming processing; It is a figure explaining the IR grooving and modification layer formation processing after planarization processing, and planarization processing.
- 4 is a flow chart showing a laser processing method including planarization processing, IR grooving, and modified layer forming processing. It is a figure which shows typically an example of the IR grooving after planarization processing, and the IR grooving and modification layer formation processing after planarization processing. It is a figure explaining laser grooving, and the planarization process and modification layer formation process after laser grooving.
- 4 is a flow chart showing a laser processing method including laser grooving, planarization processing, and modified layer formation processing. It is a figure which shows typically an example of the planarization process after laser grooving, and a modified layer formation process after laser grooving.
- the laser processing device 1 implements the laser processing method according to the embodiment.
- the laser processing apparatus 1 includes a plurality of moving mechanisms 5 and 6, a support section 7, a pair of laser processing heads 10A and 10B, a light source unit 8, and a control section 9.
- the first direction will be referred to as the X direction
- the second direction perpendicular to the first direction will be referred to as the Y direction
- the third direction perpendicular to the first and second directions will be referred to as the Z direction.
- the X and Y directions are horizontal and the Z direction is vertical.
- the moving mechanism 5 has a fixed portion 51 , a moving portion 53 and a mounting portion 55 .
- the fixing portion 51 is attached to the device frame 1a.
- the moving part 53 is attached to a rail provided on the fixed part 51 and can move along the Y direction.
- the attachment portion 55 is attached to a rail provided on the moving portion 53 and can move along the X direction.
- the moving mechanism 6 has a fixed portion 61, a pair of moving portions 63 and 64, and a pair of mounting portions 65 and 66.
- the fixed part 61 is attached to the device frame 1a.
- Each of the pair of moving parts 63 and 64 is attached to a rail provided on the fixed part 61 and can move independently along the Y direction.
- the attachment portion 65 is attached to a rail provided on the moving portion 63 and can move along the Z direction.
- the attachment portion 66 is attached to a rail provided on the moving portion 64 and can move along the Z direction. That is, each of the pair of mounting portions 65 and 66 can move along the Y direction and the Z direction with respect to the device frame 1a.
- the support part 7 is attached to a rotating shaft provided in the attachment part 55 of the moving mechanism 5, and can rotate around an axis line parallel to the Z direction. That is, the support portion 7 can move along each of the X direction and the Y direction, and can rotate about an axis line parallel to the Z direction.
- the support section 7 supports the target object 100 .
- Object 100 is a wafer.
- the object 100 includes a semiconductor substrate and a plurality of functional elements (functional element layers).
- the semiconductor substrate is, for example, a silicon substrate.
- Each functional element is two-dimensionally arranged, for example, along the surface of the semiconductor substrate.
- Each functional element is, for example, a light receiving element such as a photodiode, a light emitting element such as a laser diode, a circuit element such as a memory, or the like.
- Each functional element may be configured three-dimensionally by stacking a plurality of layers.
- the laser processing head 10A is attached to the attachment portion 65 of the moving mechanism 6.
- the laser processing head 10A irradiates the object 100 supported by the support portion 7 with the laser beam L1 (first laser beam) while facing the support portion 7 in the Z direction.
- the laser processing head 10B is attached to the attachment portion 66 of the moving mechanism 6. As shown in FIG.
- the laser processing head 10B irradiates the object 100 supported by the support portion 7 with the laser beam L2 (second laser beam) while facing the support portion 7 in the Z direction.
- the light source unit 8 has a pair of light sources 81,82.
- the light source 81 outputs laser light L1.
- the laser beam L1 is emitted from the emitting portion 81a of the light source 81 and guided to the laser processing head 10A by the optical fiber 2.
- the light source 82 outputs laser light L2.
- the laser beam L2 is emitted from the emitting portion 82a of the light source 82 and guided to the laser processing head 10B by another optical fiber 2. As shown in FIG.
- the controller 9 controls each part of the laser processing apparatus 1 (a plurality of moving mechanisms 5 and 6, a pair of laser processing heads 10A and 10B, a light source unit 8, and the like).
- the control unit 9 is configured as a computer device including a processor, memory, storage, communication device, and the like.
- the software (program) loaded into the memory or the like is executed by the processor, and the reading and writing of data in the memory and storage and the communication by the communication device are controlled by the processor.
- the control part 9 implement
- the laser processing head 10A includes a housing 11, an incident section 12, an adjusting section 13, and a condensing section .
- the housing 11 has a first wall 21 and a second wall 22 , a third wall 23 and a fourth wall 24 , and a fifth wall 25 and a sixth wall 26 .
- the first wall portion 21 and the second wall portion 22 face each other in the X direction.
- the third wall portion 23 and the fourth wall portion 24 face each other in the Y direction.
- the fifth wall portion 25 and the sixth wall portion 26 face each other in the Z direction.
- the distance between the third wall portion 23 and the fourth wall portion 24 is smaller than the distance between the first wall portion 21 and the second wall portion 22 .
- the distance between the first wall portion 21 and the second wall portion 22 is smaller than the distance between the fifth wall portion 25 and the sixth wall portion 26 .
- the distance between the first wall portion 21 and the second wall portion 22 may be equal to the distance between the fifth wall portion 25 and the sixth wall portion 26, or the distance between the fifth wall portion 25 and the sixth wall portion may be the same. It may be larger than the distance from the portion 26 .
- the first wall portion 21 is positioned on the fixed portion 61 side of the moving mechanism 6, and the second wall portion 22 is positioned on the opposite side of the fixed portion 61.
- the third wall portion 23 is located on the mounting portion 65 side of the moving mechanism 6, and the fourth wall portion 24 is located on the side opposite to the mounting portion 65 and on the laser processing head 10B side (Fig. 2).
- the fifth wall portion 25 is located on the side opposite to the support portion 7, and the sixth wall portion 26 is located on the support portion 7 side.
- the housing 11 is configured such that the housing 11 is attached to the mounting portion 65 with the third wall portion 23 arranged on the mounting portion 65 side of the moving mechanism 6 .
- the mounting portion 65 has a base plate 65a and a mounting plate 65b.
- the base plate 65a is attached to a rail provided on the moving portion 63 (see FIG. 2).
- the mounting plate 65b is erected at the end of the base plate 65a on the side of the laser processing head 10B (see FIG. 2).
- the housing 11 is attached to the mounting portion 65 by screwing the bolt 28 into the mounting plate 65b via the pedestal 27 while the third wall portion 23 is in contact with the mounting plate 65b.
- the pedestal 27 is provided on each of the first wall portion 21 and the second wall portion 22 .
- the housing 11 can be attached to and detached from the attachment portion 65 .
- the incidence part 12 is attached to the fifth wall part 25 .
- the incident part 12 causes the laser beam L ⁇ b>1 to enter the housing 11 .
- the incident portion 12 is biased toward the second wall portion 22 (one wall portion) in the X direction, and biased toward the fourth wall portion 24 in the Y direction. That is, the distance between the incident portion 12 and the second wall portion 22 in the X direction is smaller than the distance between the incident portion 12 and the first wall portion 21 in the X direction, and the distance between the incident portion 12 and the fourth wall portion 24 in the Y direction is smaller. is smaller than the distance between the entrance portion 12 and the third wall portion 23 in the X direction.
- the incident part 12 is configured so that the connection end part 2a of the optical fiber 2 can be connected.
- the connection end 2a of the optical fiber 2 is provided with a collimator lens for collimating the laser light L1 emitted from the output end of the fiber, and is not provided with an isolator for suppressing return light.
- the isolator is provided in the middle of the fiber on the light source 81 side of the connection end 2a. Thereby, miniaturization of the connecting end portion 2a, and further miniaturization of the incident portion 12 is achieved.
- An isolator may be provided at the connection end portion 2a of the optical fiber 2.
- the adjustment unit 13 is arranged inside the housing 11 .
- the adjuster 13 adjusts the laser beam L1 incident from the incident part 12 .
- Each component of the adjustment section 13 is attached to an optical base 29 provided inside the housing 11 .
- the optical base 29 is attached to the housing 11 so as to divide the area inside the housing 11 into an area on the side of the third wall 23 and an area on the side of the fourth wall 24 .
- the optical base 29 is integrated with the housing 11 . Details of each configuration of the adjustment section 13 attached to the optical base 29 on the fourth wall section 24 side will be described later.
- the condensing part 14 is arranged on the sixth wall part 26 . Specifically, the condensing portion 14 is arranged on the sixth wall portion 26 while being inserted into a hole 26 a formed in the sixth wall portion 26 .
- the light collecting unit 14 emits the laser light L1 adjusted by the adjusting unit 13 to the outside of the housing 11 while collecting the laser light L1.
- the condensing portion 14 is biased toward the second wall portion 22 (one wall portion) in the X direction, and biased toward the fourth wall portion 24 in the Y direction.
- the distance between the condensing part 14 and the second wall part 22 in the X direction is smaller than the distance between the condensing part 14 and the first wall part 21 in the X direction, and the distance between the condensing part 14 and the fourth wall part 21 in the Y direction
- the distance to the wall portion 24 is smaller than the distance between the light collecting portion 14 and the third wall portion 23 in the X direction.
- the adjustment section 13 has an attenuator 31, a beam expander 32, and a mirror 33.
- the incident section 12 and the attenuator 31, beam expander 32 and mirror 33 of the adjusting section 13 are arranged on a straight line (first straight line) A1 extending along the Z direction.
- the attenuator 31 and the beam expander 32 are arranged between the incident part 12 and the mirror 33 on the straight line A1.
- the attenuator 31 adjusts the output of the laser beam L1 incident from the incident portion 12 .
- the beam expander 32 expands the diameter of the laser light L1 whose output has been adjusted by the attenuator 31 .
- the mirror 33 reflects the laser beam L1 whose diameter has been expanded by the beam expander 32 .
- the adjusting section 13 further has a reflective spatial light modulator 34 and an imaging optical system 35 .
- the reflective spatial light modulator 34 and imaging optical system 35 of the adjusting section 13, and the condensing section 14 are arranged on a straight line (second straight line) A2 extending along the Z direction.
- a reflective spatial light modulator 34 modulates the laser light L1 reflected by the mirror 33 .
- the reflective spatial light modulator 34 is, for example, a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) spatial light modulator (SLM: Spatial Light Modulator).
- the imaging optical system 35 constitutes a double-telecentric optical system in which the reflecting surface 34a of the reflective spatial light modulator 34 and the entrance pupil surface 14a of the condensing section 14 are in an imaging relationship.
- the imaging optical system 35 is composed of three or more lenses.
- the straight lines A1 and A2 are located on a plane perpendicular to the Y direction.
- the straight line A1 is located on the second wall portion 22 side (one wall portion side) with respect to the straight line A2.
- the laser beam L1 enters the housing 11 from the incident portion 12, travels along the straight line A1, is reflected by the mirror 33 and the reflective spatial light modulator 34 in sequence, and then travels along the straight line A2.
- the light travels upward and exits from the housing 11 through the condensing section 14 .
- the order of arrangement of the attenuator 31 and the beam expander 32 may be reversed.
- the attenuator 31 may be arranged between the mirror 33 and the reflective spatial light modulator 34 .
- the adjustment unit 13 may have other optical components (for example, a steering mirror or the like arranged in front of the beam expander 32).
- the laser processing head 10A further includes a dichroic mirror 15, a measurement section 16, an observation section 17, a drive section 18, and a circuit section 19.
- the dichroic mirror 15 is arranged between the imaging optical system 35 and the condensing section 14 on the straight line A2. In other words, the dichroic mirror 15 is arranged inside the housing 11 between the adjusting section 13 and the condensing section 14 . The dichroic mirror 15 is attached to the optical base 29 on the fourth wall 24 side. The dichroic mirror 15 transmits the laser beam L1. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 is preferably, for example, a cube type or two plate types arranged to have a twisted relationship.
- the measurement unit 16 is arranged in the housing 11 on the first wall 21 side (the side opposite to the one wall) with respect to the adjustment unit 13 .
- the measuring section 16 is attached to the optical base 29 on the fourth wall section 24 side.
- the measurement unit 16 outputs measurement light L10 for measuring the distance between the surface of the object 100 (for example, the surface on which the laser beam L1 is incident) and the light collecting unit 14, and outputs the measurement light L10 through the light collecting unit 14. , the measuring light L10 reflected by the surface of the object 100 is detected. That is, the measurement light L10 output from the measurement unit 16 is irradiated onto the surface of the object 100 via the light condensing unit 14, and the measurement light L10 reflected by the surface of the object 100 is transmitted through the light condensing unit 14. is detected by the measuring unit 16.
- the measurement light L10 output from the measurement unit 16 is sequentially reflected by the beam splitter 20 and the dichroic mirror 15 attached to the optical base 29 on the fourth wall 24 side, and is emitted from the light collection unit 14.
- the light is emitted outside the housing 11 .
- the measurement light L10 reflected by the surface of the object 100 enters the housing 11 from the light collecting unit 14, is sequentially reflected by the dichroic mirror 15 and the beam splitter 20, enters the measurement unit 16, and reaches the measurement unit 16. detected by
- the observation section 17 is arranged on the first wall section 21 side (the side opposite to the one wall section side) with respect to the adjustment section 13 in the housing 11 .
- the observation section 17 is attached to the optical base 29 on the fourth wall section 24 side.
- the observation unit 17 outputs observation light L20 for observing the surface of the object 100 (for example, the surface on which the laser beam L1 is incident), which is reflected by the surface of the object 100 via the light collecting unit 14 .
- the observed light L20 is detected. That is, the observation light L20 output from the observation unit 17 is irradiated onto the surface of the object 100 via the light collecting unit 14, and the observation light L20 reflected by the surface of the object 100 is transmitted through the light collecting unit 14. is detected by the observation unit 17.
- the observation light L20 output from the observation unit 17 is transmitted through the beam splitter 20, reflected by the dichroic mirror 15, and emitted from the light collection unit 14 to the outside of the housing 11.
- the observation light L20 reflected by the surface of the object 100 enters the housing 11 from the light collecting unit 14, is reflected by the dichroic mirror 15, passes through the beam splitter 20, enters the observation unit 17, and enters the observation unit 17. 17 is detected.
- the wavelengths of the laser light L1, the measurement light L10, and the observation light L20 are different from each other (at least their center wavelengths are shifted from each other).
- the driving section 18 is attached to the optical base 29 on the fourth wall section 24 side. It is attached to the sixth wall portion 26 of the housing 11 .
- the drive unit 18 moves the condensing unit 14 arranged on the sixth wall 26 along the Z direction, for example, by driving force of a piezoelectric element.
- the circuit section 19 is arranged inside the housing 11 on the third wall section 23 side with respect to the optical base 29 . That is, the circuit section 19 is arranged on the third wall section 23 side with respect to the adjustment section 13 , the measurement section 16 and the observation section 17 in the housing 11 .
- the circuit section 19 is, for example, a plurality of circuit boards.
- the circuit section 19 processes the signal output from the measuring section 16 and the signal input to the reflective spatial light modulator 34 .
- the circuit section 19 controls the driving section 18 based on the signal output from the measuring section 16 .
- the circuit unit 19 maintains a constant distance between the surface of the object 100 and the light collecting unit 14 based on the signal output from the measurement unit 16 (that is, the distance between the surface of the object 100 and the The drive unit 18 is controlled so that the distance to the focal point of the laser light L1 is maintained constant.
- the housing 11 is provided with a connector (not shown) to which wiring for electrically connecting the circuit section 19 to the control section 9 (see FIG. 1) or the like is connected.
- the laser processing head 10B includes a housing 11, an incident section 12, an adjusting section 13, a light collecting section 14, a dichroic mirror 15, a measuring section 16, an observing section 17, A driving unit 18 and a circuit unit 19 are provided.
- each configuration of the laser processing head 10B is, as shown in FIG. are arranged so as to have a symmetrical relationship with
- the housing (first housing) 11 of the laser processing head 10A has the fourth wall portion 24 located on the laser processing head 10B side with respect to the third wall portion 23, and the sixth wall portion 26 located on the fifth wall. It is attached to the attachment portion 65 so as to be positioned on the support portion 7 side with respect to the portion 25 .
- the fourth wall portion 24 is located on the laser processing head 10A side with respect to the third wall portion 23, and the sixth wall portion 26 is located on the side of the laser processing head 10A.
- 5 is attached to the attachment portion 66 so as to be positioned on the support portion 7 side with respect to the wall portion 25 .
- the housing 11 of the laser processing head 10B is configured such that the housing 11 is attached to the mounting portion 66 with the third wall portion 23 arranged on the mounting portion 66 side. Specifically, it is as follows.
- the mounting portion 66 has a base plate 66a and a mounting plate 66b.
- the base plate 66 a is attached to rails provided on the moving portion 63 .
- the mounting plate 66b is erected at the end of the base plate 66a on the side of the laser processing head 10A.
- the housing 11 of the laser processing head 10B is attached to the attachment portion 66 with the third wall portion 23 in contact with the attachment plate 66b.
- the housing 11 of the laser processing head 10B can be attached to and detached from the mounting portion 66 . [Example of processing by laser processing equipment (stealth dicing)]
- FIG. 6A schematically shows a mode of forming a modified layer inside the object 1000 by irradiating the object 1000 having a mirror surface with the laser beam L.
- FIG. 6B shows the rear surface 1000b, which is the incident surface (irradiation surface) of the laser light L.
- FIG. 6(c) shows a cross section of the object 1000.
- the target object 1000 is a wafer, and has a back surface 1000b that serves as an incident surface for the laser light L and a front surface 1000a on which functional elements are formed.
- FIG. 6A schematically shows a mode of forming a modified layer inside the object 1000 by irradiating the object 1000 having a mirror surface with the laser beam L.
- FIG. FIG. 6B shows the rear surface 1000b, which is the incident surface (irradiation surface) of the laser light L.
- FIG. 6(c) shows a cross section of the object 1000.
- the target object 1000 is a wafer, and has a back surface 1000b that serves
- the rear surface 1000b of the object 1000 which is the incident surface of the laser beam L, is a mirror surface (see FIG. 6B).
- a modified layer 1050 SD layer is appropriately formed inside the object 1000 as shown in FIG. 6(c).
- FIG. 7(a) schematically shows a mode of forming a modified layer inside the object 100 by irradiating the object 100 with the rough back surface 100b with the laser beam L.
- FIG. FIG. 7B shows the rear surface 100b, which is the incident surface (irradiation surface) of the laser light L.
- FIG. FIG. 7(c) shows a cross section of the object 100.
- the target object 100 is a wafer, and has a back surface 100b that serves as an incident surface for the laser light L and a front surface 100a on which functional elements are formed.
- the rear surface 100b of the object 100 which is the incident surface of the laser beam L, is a rough surface (rough surface) with unevenness (see FIG. 7B).
- the rough back surface 100b means, for example, a back surface 100b with an arithmetic mean roughness Ra>0.02 ⁇ m.
- the object 100 having such a rough back surface 100b includes, for example, a wafer having a satin-finished back surface 100b (for example, a wafer of a predetermined size or less such as 8 inches) or a wafer that is not sufficiently ground.
- a modified layer cannot be properly formed inside.
- FIG. 7C there is a possibility that the region of the modified layer 150 cannot be sufficiently formed inside the object 100 . In order to avoid such a situation, it is conceivable to sufficiently grind the wafer, for example, but there is a problem that the cost required for grinding increases.
- a modified layer is formed inside the object 100 by irradiating the back surface 100b with the laser beam L.
- the back surface 100b which is the incident surface of the laser light L, is planarized by laser annealing.
- Laser annealing is a technique for modifying materials such as melting and recrystallization on an irradiated surface by irradiating a laser beam.
- the irradiated surface is recrystallized and flattened by laser annealing.
- the flattened back surface 100b is irradiated with the laser beam L for forming the modified layer, so the above-described problem is solved, and the modified layer is appropriately formed inside the object 100.
- the modified layer is appropriately formed inside the object 100.
- FIG. 8 is a diagram for explaining the planarization process and the modified layer formation process after the planarization process.
- a stealth dicing process that forms a modified layer is performed to cut the object 100, which is a wafer, into a plurality of chips.
- the light source 81 outputs the laser beam L1 for laser annealing and the laser processing head 10A irradiates the object 100 with the laser beam L1.
- the light source 82 outputs the laser beam L2 for forming the modified layer and the laser processing head 10B irradiates the object 100 with the laser beam L2.
- the light source 81 is, for example, a light source that emits an ultrashort pulse laser.
- the light source 82 is, for example, a light source that emits a nanosecond pulse laser.
- the pulse pitch of the laser beam L1 for laser annealing emitted from the light source 81 is at least shorter than the pulse pitch of the laser beam L2 for formation of the modified layer emitted from the light source 82 (details will be described later).
- the light source 81 of the laser beam L1 for the flattening process and the laser processing head 10A and the light source 82 of the laser beam L2 for the modified layer forming process and the laser processing head 10B are mounted separately. , after the flattening process, the laser for the modified layer forming process can perform follow-up processing.
- a laser dicer for flattening processing and a laser dicer for modified layer forming processing may be provided separately in two separate devices. In this case, processing can be performed in parallel by two apparatuses, so that the tact time can be increased.
- the laser light L1 and the laser light L2 may be emitted from a common light source 82 . That is, the laser light L1 and the laser light L2 may be the same kind of laser (for example, a transmissive laser emitted from the light source 82 that emits a nanosecond pulse laser).
- the laser beam L1 and the laser beam L2 may be emitted from a common laser processing head.
- the object 100 is prepared, and the object 100 is supported by the support section 7 (see FIG. 1).
- the object 100 has a back surface 100b that serves as an incident surface for the laser light L, and a front surface 100a on which functional elements are formed.
- the moving mechanism 6 controlled by the control unit 9 moves the focal point of the laser beam L1 along one line extending in one direction on the back surface 100b.
- the light source 81 controlled by the controller 9 outputs the laser beam L1 for laser annealing.
- the control unit 9 controls the light source 81 and the moving mechanism 6 so that the back surface 100b of the object 100 is irradiated with the laser beam L1 and the back surface 100b, which is the irradiated surface, is flattened by laser annealing. to implement.
- the first control is control related to the first step (flattening process) of irradiating the back surface 100b with the laser beam L1 and planarizing the back surface 100b by laser annealing.
- the rear surface 100b is irradiated with a laser beam L1 to planarize the rear surface 100b.
- the one line described above becomes a laser annealing line 100x on which laser annealing has been performed.
- the laser annealing line 100x includes at least a dicing line irradiated with a laser beam L2 for forming a modified layer, which will be described later.
- the planarization process may be performed on a roughened region (for example, a dicing street roughened by etching) on the surface 100a on the device side.
- the moving mechanism 6 controlled by the controller 9 moves the laser processing head so that the focal point of the laser beam L2 is positioned along the laser annealing line 100x. 10B is moved, and the light source 82 controlled by the controller 9 outputs the laser light L2 for forming the modified layer. That is, the control unit 9 controls the light source 82 and the moving mechanism 6 so that the flattened back surface 100b (irradiation surface) is irradiated with the laser beam L2 to form a modified layer inside the object 100. 2nd control is implemented.
- the second control is control related to the second step (modified layer forming process) of irradiating the back surface 100b flattened in the first step with the laser beam L2 to form a modified layer inside the object 100. .
- an expanding process (FIG. 8(d)) is performed in the dividing step, and the object 100 is cut into a plurality of chips.
- the expanding process (FIG. 8F) may be performed after the grinding process (see FIG. 8E).
- the laser light L1 and the laser light L2 may be the same type of laser emitted from a common light source.
- FIG. 9 shows whether the laser beam L1 and the laser beam L2 of the same kind emitted from a common light source (for example, the light source 82) are appropriately planarized by laser annealing while changing the conditions of the laser beam L1. This is the result of determining whether or not.
- the above experiment was performed on the object 100 which is a silicon wafer (crystal orientation ⁇ 100>) with a wafer thickness of 300 ⁇ m and a grinding count of 2000.
- the wavelength of the laser light L1 and the laser light L2 was 1099 nm
- the pulse width was 700 nsec
- the energy was 90 ⁇ J.
- the number of branches of the laser beam L2 in the processing progress direction was 1, the frequency was 120 kHz, the processing speed was 800 mm/sec, and the pulse pitch was 6.7 ⁇ m.
- Such processing conditions for the laser beam L2 are conditions for forming a desired modified layer on the object 100 . Then, as shown in FIG.
- the planarization process is appropriately performed by the laser beam L1. It was determined whether or not In this experiment, the back surface 100b of the object 100 after laser annealing is judged to be mirror-finished. It was determined that the flattening process was not performed appropriately.
- FIG. 10 is a diagram showing laser annealing results of the laser beams L1 described above. As shown in FIG. 9, for the laser beam L1, the number of branches in the processing progress direction is 1, the frequency is 80 kHz, and the pulse pitch is changed to 10 ⁇ m, 5 ⁇ m, 2.5 ⁇ m, 1 ⁇ m, and 0.2 ⁇ m while changing the processing speed.
- the laser beams L1 with pulse pitches of 1 ⁇ m and 0.2 ⁇ m passed the specular judgment.
- FIG. 10 is a diagram showing laser annealing results of the laser beams L1 described above. As shown in FIG.
- the laser beam L1 with pulse pitches of 10 ⁇ m, 5 ⁇ m, and 2.5 ⁇ m causes a ripple shape on the laser annealing line 100x, and the mirror surface cannot be mirror-finished, and the flattening process is not performed appropriately. Not done.
- the laser annealing line 100x does not have a ripple shape, and the laser annealing line 100x is mirror-finished. It is done.
- the shorter the pulse pitch the more appropriately the flattening process is performed. This is because the shorter the pulse pitch, the more continuously melted, recrystallized, and flattened regions are formed by laser annealing.
- the pulse pitch of the laser beam L1 is set at least shorter than the pulse pitch of the laser beam L2.
- the frequency of the laser light L1 was set to 150 kHz, which was higher than the frequency of the laser light L2 of 120 kHz, so that the mirror surface determination of the laser light L1 passed.
- the next pulse is applied before the irradiated area cools down, so that heat is accumulated and recrystallization is appropriately performed, and the irradiated surface can be flattened. can.
- the planarization process can be performed appropriately.
- the number of branches of the laser beam L1 in the processing progress direction is set, for example, to be greater than the number of branches of the laser beam L2 in the processing progress direction.
- the branching of the laser light L1 will be described with reference to FIGS. 11 to 13.
- FIG. The branching of the laser beam L1 here refers to branching in the X and Y directions (horizontal branching) rather than branching in the Z direction (vertical branching).
- the lateral branching of the laser beam L1 includes branching in the processing progress direction and branching in a direction intersecting the processing progress direction (and parallel to the irradiation surface of the laser beam L1). In the following, two examples of the lateral branching may simply be referred to as branching in the direction of machining progress and branching in a direction crossing the direction of machining progress.
- FIG. 11 is a diagram for explaining improvement of flatness by lateral branching.
- the beams obtained by laterally branching the laser light L1 may partly overlap each other in the irradiation range on the rear surface 100b, which is the irradiation surface.
- FIG. 11 shows the result of verifying the flatness of the laser annealing line 100x while changing the conditions of the laser beam L1.
- the upper part shows the possibility of flattening and the flatness when the back surface 100b is irradiated twice with the 36 ⁇ J laser beam L1 without lateral branching so as not to overlap each other.
- the flattenability and flatness when the back surface 100b is irradiated once with the laser beam L1 of 72 ⁇ J are shown. It shows whether or not the back surface 100b is irradiated once so as to overlap each other, and the flatness.
- whether the planarization is possible or not indicates whether or not the laser annealing line 100x is formed. It shows that the anneal line 100x is not formed.
- the flatness here indicates the flatness (less unevenness) in the flattened region (laser annealing line 100x), and "o" in FIG. 11 indicates that the laser annealing line 100x is sufficiently flat.
- ⁇ indicates that the laser annealing line 100x includes a non-flat region
- X indicates that the laser annealing line 100x is not flat to the extent that there is no planarized region. It should be noted that in the region showing flatness in FIG. 11, the unevenness of the irradiation surface is indicated by waveforms. As described above, the total energy of laser light L1 is the same in each example.
- the laser beam L1 has a convex flatness at the beam center and a concave portion away from the beam center, as shown in the middle part of FIG. At L1, the flatness is not sufficient (flatness " ⁇ ").
- the beams of the laser light L1 with lateral branching 36 ⁇ J ⁇ 2 branches, branch interval of 8 ⁇ m
- branch interval of 8 ⁇ m branch interval of 8 ⁇ m
- each beam is irradiated so as to overlap each other (so that the irradiation range overlaps), even if there is unevenness in flatness between the beam center and a point away from the beam center, the overlapping beams Since the unevenness is suppressed by, the flatness is also "O". In this manner, the irradiation ranges of the beams of the laser light L1 partially overlap each other on the back surface 100b, thereby improving the flatness in the flattening process.
- FIG. 12 is a diagram explaining tact-up and expansion of flattening width by lateral branching.
- FIG. 12(a) shows an example of 4 branches in the direction of progress of machining.
- two-branching with an interval of 8 ⁇ m for improving flatness, two-branching with an interval of 1 ⁇ m is performed. That is, as shown in FIG.
- the laser beam L1 is branched into two so that the distance between the condensing points L111 and L113 is 8 ⁇ m, and the distance between the condensing points L111 and L112 and Each of the light beams L113 and L114 is branched into two such that the distance between the light condensing points L113 and L114 is 1 ⁇ m.
- the laser beam L1 split into four in total is irradiated in this way, the beams with intervals of 1 ⁇ m are irradiated while the beams with intervals of 8 ⁇ m overlap as described above, thereby improving the flatness in the planarization process.
- the pulse pitch can be lengthened, and the processing speed can be increased.
- the pulse pitch when the number of branches in the processing progress direction is 1, the pulse pitch must be 1 ⁇ m in order to set the beam interval to 1 ⁇ m.
- the pulse pitch When a 1 ⁇ m branched beam is irradiated at , the pulse pitch should be 2 ⁇ m in order to set the beam interval to 1 ⁇ m.
- FIG. 12(b) shows an example of branching in the direction intersecting with the machining progress direction. More specifically, FIG. 12(b) shows an example of branching into two in the machining advancing direction and branching into two in the direction intersecting the machining advancing direction, for a total of four branches. FIG. 12(b) shows condensing points L115, L116, L117, and L118 of the four beams of the laser beam L1. In the example shown in FIG.
- the distance between the condensing points L115 and L116 facing each other in the processing progress direction, and the distance between the converging points L117 and L118 facing each other in the processing progress direction The distance is 8 ⁇ m, the distance between the condensing points L115 and L117 facing each other in the direction intersecting the processing progress direction, and the converging points L116 and L118 facing each other in the direction intersecting the processing progress direction.
- the laser light L1 is branched so that the interval between . In this way, the laser beam L1 is split in the direction intersecting the processing progress direction, so that the width of the laser annealing line 100x flattened by laser annealing with the laser beam L1 (the length in the direction intersecting the processing progress direction ) can be increased.
- the number of branches in the direction intersecting the processing progress direction of the laser beam L1 for laser annealing may be greater than the number of branches in the direction intersecting the processing progress direction of the laser beam L2 for forming the modified layer.
- the laser beam L1 may have a top hat shape rather than a Gaussian shape.
- the annealing width may be adjusted by adjusting the position of the focal point. That is, if a wide annealing width is desired, the position of the focal point may be deep, and if a narrow annealing width is desired, the position of the focal point may be shallow.
- FIG. 13 is a diagram explaining the effect of branching the laser light L1 in the direction intersecting the processing progress direction.
- FIG. 13A shows the laser beam L2 after being branched in the direction intersecting the processing progress direction (after performing the flattening process) in order to form a laser annealing line 100x having a predetermined width. shows an example of performing a modified layer forming process by .
- FIG. 13(b) shows that after irradiating the laser beam L1 twice in the direction intersecting the processing progress direction to form a laser annealing line 100x having a predetermined width (after performing a flattening process), the laser An example of performing a modified layer forming process with light L2 is shown.
- the laser annealing line 100x having a predetermined width can be formed by the laser beam L1, but in the example shown in FIG. ), in the example shown in FIG. 13(a), laser annealing line 100x having a predetermined width is formed by one irradiation of laser light L1 by branching laser light L1 in the direction intersecting the processing progress direction. can be formed.
- the width of the laser annealing line 100x is relatively large, the number of passes for irradiating the laser beam L1 can be reduced by branching the laser beam L1 in the direction intersecting the processing progress direction, resulting in a flat surface. The time required for conversion processing can be shortened.
- FIG. 14 is a diagram showing an example of laser annealing and modified layer formation for each condensing position.
- FIG. 14A shows a case where laser annealing is performed so that the focal point of the laser beam L1 is located inside the object 100.
- FIG. 150 in addition to forming a laser annealing line 100x on the rear surface 100b by the laser beam L1 as shown in FIG. A modified layer 150 may be formed.
- the laser beam L1 for laser annealing has a shorter pulse pitch than the laser beam L2 for forming the modified layer. difficult.
- the modified layer itself formed by the laser beam L1 does not become the starting point of splitting.
- a crack generated in the modified layer formed by L2 leads to a crack in the modified layer formed by the above-described laser beam L1, and the crack in the modified layer formed by the laser beam L1 assists the splitting. .
- the number of passes of the laser beam L2 for forming the modified layer can be reduced.
- the irradiation surface is irradiated with the laser beam L1 so as not to form a modified layer inside the object 100.
- the focal point of the laser beam L1 may be set to a position outside the object 100 (for example, a position above the object 100).
- laser annealing lines 100x are formed on the back surface 100b by the laser beam L1, while the laser beam L1 is applied to the inside of the object 100 as shown in FIG. 14(f). Formation of the modified layer can be prevented.
- the same planarization process as in the case of condensing light inside the object 100 is performed by making the irradiation area approximately the same as in the case of condensing light inside the object 100. It is possible. Note that even if the focal point of the laser beam L1 is positioned outside the object 100, a modified layer may be formed in the vicinity of the irradiated surface depending on other conditions.
- the laser beam L1 and the laser beam L2 are the same type of laser emitted from a common light source, for example, the laser beam L1 for laser annealing has a wavelength of 1099 nm, a pulse width of 700 nsec, a frequency of 150 kHz, and a processing speed of 150 kHz.
- the pulse pitch is 1 ⁇ m
- the condensing point is set outside (above) the object 100
- the total output is set to 14 W.
- the wavelength of the laser light L2 for forming the modified layer is 1099 nm
- the pulse width is 700 nsec
- the frequency is 120 kHz
- the processing speed is 800 mm/sec
- the pulse pitch is 6.67 ⁇ m
- the modified layers with different depths are formed. It is conceivable to set the forming power to 2.78W and 1.85W.
- the wavelength of the laser light L1 for laser annealing is 1064 nm
- the pulse width is 9 psec
- the frequency is 1 MHz
- the processing speed is 1000 mm/sec
- the pulse pitch is set to 1 ⁇ m
- the total output to 30 W
- the number of burst pulses to 2.
- burst refers to division of each pulse, and the same effect as the branching of laser light described above can be obtained.
- the wavelength of the laser light L2 for forming the modified layer is 1099 nm
- the pulse width is 700 nsec
- the frequency is 120 kHz
- the processing speed is 800 mm/sec
- the pulse pitch is 6.67 ⁇ m
- the modified layers with different depths are formed. It is conceivable to set the forming power to 2.78W and 1.85W.
- FIGS. 15 and 16 setting screens of the GUI 111 for carrying out the first step related to the planarization process and the second process related to the modified layer forming process described above will be described.
- 15 and 16 (a) to (d) schematically show the steps to be performed, and (e) shows a setting screen of the GUI 111.
- FIG. Now, as shown in FIGS. 15(a) to 15(d), an object 100 is prepared (see FIG. 15(a)) and flattened so that laser annealing lines 100x are formed on all dicing lines. After the modification treatment is performed (see FIGS.
- the focal point of the laser beam L1 is set at a position above the object 100 .
- the Z height becomes, for example, a negative value.
- the Z height is "-30”
- the output is "14 ⁇ J”
- the processing speed is "150 mm/sec”
- the laser condition is "A”
- the side branch is "-8 ⁇ m”.
- a of the laser condition is a condition of the laser beam L1 set in advance to be selectable, for example, a pulse width of 700 nsec and a frequency of 150 kHz.
- “Yes-8 ⁇ m” for lateral branching means that there is lateral branching and the branch interval is 8 ⁇ m.
- the Z height, output, speed, laser conditions, and presence/absence of lateral branching for two passes relating to two modified layers 112 having different depths are set. set.
- the Z height of the first pass is "64”
- the output is "2.78 ⁇ J”
- the processing speed is "800 mm/sec”
- the laser condition is "B”
- the side branch is "none”.
- the Z height of the second pass is "24”
- the output is "1.85 ⁇ J”
- the processing speed is "800 mm/sec”
- the laser condition is "B”
- the side branch is "none".
- the laser condition "B” is a condition of the laser light L2 that is set in advance to be selectable, for example, a pulse width of 700 nsec and a frequency of 120 kHz. Although the pulse pitch can be calculated by processing speed/frequency, it is not displayed on the setting screen of the GUI 111 in the example shown in FIG. 15(e).
- the setting screen of the GUI 111 displays the processing order of the two recipes (recipe 1 first, recipe 2 later).
- FIGS. 16(a) to 16(d) an object 100 is prepared (see FIG. 16(a)), and one laser annealing line 100x is formed on one dicing line.
- a flattening process is performed (see FIG. 16(b)), and stealth dicing is performed along the formed single laser annealing line 100x to form a modified layer 112 (see FIG. 16(c) ), the processing shown in FIGS. 16(b) and 16(c) is performed on all the dicing lines to form the modified layer 112 on all the dicing lines (see FIG. 16(d)). That is, it is assumed that the planarization scan and the modified layer formation scan are repeatedly performed for each dicing line.
- FIG. 17 is a flowchart showing a laser processing method including planarization processing and modified layer formation processing.
- step S1 an object 100, which is a wafer, is put into the laser processing apparatus 1, and the object 100 is supported by the support section 7 (step S1). Then, alignment of the irradiation position of the laser light is performed (step S2). Subsequently, the Z height is set based on the set recipe (step S3).
- step S4 a flattening process is performed (step S4). Specifically, the control unit 9 controls the light source 81 and the moving mechanism 6 so that the back surface 100b of the object 100 is irradiated with the laser beam L1 and the back surface 100b, which is the irradiated surface, is flattened by laser annealing. be.
- a modified layer forming process for forming a modified layer for dividing the object 100 is performed (step S5).
- the light source 82 and the moving mechanism 6 are controlled by the control unit 9 so that a modified layer is formed inside the object 100 whose back surface 100b (irradiation surface) that has been flattened is irradiated with the laser beam L2. is controlled.
- the object 100 which is a wafer, is taken out from the laser processing apparatus 1 (step S6).
- IR grooving here is a process of irradiating a functional element formed on the front surface 100a of the object 100 with a laser beam from the back surface 100b side to form a weakened region in the functional element.
- a weakened region is a region in which a functional element is weakened. To weaken includes to embrittle.
- the weakened region can also be said to be a region where traces are produced by laser irradiation, and is a region that is more likely to be cut or destroyed than the non-treated region.
- the weakened region may be formed continuously in a line shape in at least a partial region of the functional element, or may be formed intermittently according to the pulse pitch of laser irradiation.
- the back surface 100b irradiated with the laser light is damaged in the IR grooving, there is a possibility that the laser beam incident from the back surface 100b cannot properly perform the IR grooving on the functional elements on the front surface 100a (device surface). There is a problem that the energy that can be used is limited. Therefore, in this embodiment, the back surface 100b of the object 100 is planarized by laser annealing before IR grooving.
- FIG. 18 is a diagram for explaining the planarization process, and the IR grooving and modified layer formation process after the planarization process.
- an object 100 is prepared and supported by the support section 7 (see FIG. 1).
- the moving mechanism 6 controlled by the control unit 9 moves the focal point of the laser beam L1 along one line extending in one direction on the back surface 100b.
- the light source 81 controlled by the controller 9 outputs the laser beam L1 for laser annealing.
- the light source 81 here is, for example, a light source that emits an ultrashort pulse laser.
- the control unit 9 controls the light source 81 and the moving mechanism 6 so that the back surface 100b of the object 100 is irradiated with the laser beam L1 and the back surface 100b, which is the irradiated surface, is flattened by laser annealing. to implement.
- the first control is control related to the first step (flattening process) of irradiating the back surface 100b with the laser beam L1 and planarizing the back surface 100b by laser annealing.
- the back surface 100b before the IR grooving (first grooving) step is irradiated with the laser beam L1.
- the one line described above becomes a laser annealing line 100x on which laser annealing has been performed.
- the laser annealing line 100x includes at least a line irradiated with laser light in IR grooving (that is, a dicing line).
- the moving mechanism 6 controlled by the control unit 9 moves the laser beam L3 for IR grooving along the laser annealing line 100x.
- the laser processing head 10A is moved as above, and a light source 81 (for example, a light source that emits an ultrashort pulse laser) controlled by the controller 9 outputs a laser beam L3 related to IR grooving. That is, the control unit 9 controls the light source 81 and the moving mechanism 6 so that the laser beam L3 is irradiated from the back surface 100b of the object 100 to form the weakened region 100y in the functional element layer on the front surface 100a.
- 1 grooving control is performed.
- the first grooving control is a first grooving step (IR grooving). IR grooving is thereby performed on the functional element on the surface 100a to form a weakened region 100y in the functional element.
- the moving mechanism 6 controlled by the control unit 9 moves the laser processing head 10B so that the focal point of the laser beam L2 is positioned along the laser annealing line 100x. is moved, and the light source 82 controlled by the control unit 9 outputs the laser light L2 for forming the modified layer.
- the light source 82 here is, for example, a light source that emits a nanosecond pulse laser.
- the control unit 9 controls the light source 82 and the moving mechanism 6 so that a modified layer is formed inside the object 100 whose back surface 100b (irradiation surface) is irradiated with the laser beam L2. Enforce controls.
- the second control is control related to the second step (modified layer forming process) of irradiating the back surface 100b flattened in the first step with the laser beam L2 to form a modified layer inside the object 100. .
- an expanding process (FIG. 18(e)) is performed in the dividing step, and the object 100 is cut into a plurality of chips.
- the expanding process (FIG. 18G) may be performed after the grinding process (see FIG. 18F).
- the light source 81 for flattening and the light source 81 for IR grooving are shared (for example, a light source that emits a transmissive ultrashort pulse laser), but the present invention is not limited to this.
- the light source for flattening and the light source for IR grooving may be separated.
- the light source involved in the planarization process may be a light source that emits light with an absorptive wavelength such as 532 nsec.
- the light source for IR grooving may be a light source common to the light source for the modified layer forming process (for example, a light source that emits a nanosecond pulse laser).
- the laser dicer for planarization processing and IR grooving and the laser dicer for modified layer formation processing may be shared. , may be provided as separate devices.
- FIG. 19 is a flow chart showing a laser processing method including planarization, IR grooving, and modified layer formation.
- FIG. 20 is a diagram schematically showing an example of a planarization process, IR grooving after the planarization process, and a modified layer formation process. An example of processing in which an apparatus for planarization processing and IR grooving and an apparatus for forming a modified layer are separate apparatuses will be described below.
- the light source for the flattening process and the IR grooving is a common light source that emits an ultrashort pulse laser, and is described as the "light source 81" described above.
- the light source for the modified layer forming process is a light source of a device different from the device for the flattening treatment and IR grooving, it is referred to as a "light source 82" for convenience of explanation.
- an object 100 which is a wafer, is put into a device related to planarization processing and IR grooving in the laser processing device 1 (step S11).
- the object 100 is set so that the rear surface 100b can be irradiated with a laser beam (see FIG. 20(a)).
- alignment of the irradiation position of the laser light is performed (step S12).
- the Z height is set based on the set recipe (step S13).
- a flattening process is performed (step S14). Specifically, the control unit 9 controls the light source 81 and the moving mechanism 6 so that the back surface 100b of the object 100 is irradiated with the laser beam L1 and the back surface 100b, which is the irradiated surface, is flattened by laser annealing. be.
- the planarization process all the laser annealing lines 100x are sequentially formed line by line (see FIGS. 20(b) and 20(c)).
- IR grooving is performed after all the laser annealing lines 100x are formed (step S15). Specifically, the light source 81 and the light source 81 are moved by the controller 9 so that the laser beam L3 is irradiated from each laser annealing line 100x on the back surface 100b of the object 100 and the weakened region 100y is formed in the functional element layer on the front surface 100a. Mechanism 6 is controlled (see FIG. 20(d)). Then, the target object 100, which is a wafer, is taken out from the device related to the planarization processing and IR grooving in the laser processing device 1 (step S16).
- planarization process and IR grooving have been described assuming that after all the laser annealing lines 100x are formed, the laser beam L3 is irradiated from each laser annealing line 100x on the back surface 100b to form each weakened region 100y. but not limited to this. That is, the planarization process and the IR grooving are performed by forming a laser annealing line 100x for each line (see FIG. 20(f)) and then irradiating the laser beam L3 from the laser annealing line 100x to form the functional element layer on the surface 100a. All the weakened regions 100y may be formed (see FIG. 20(h)) by repeating the process of forming the weakened regions 100y (see FIG. 20(g)).
- step S16 the target object 100, which is a wafer for which the processes up to step S16 have been completed, is put into the apparatus related to the modified layer forming process in the laser processing apparatus 1 (step S17). Then, alignment of the irradiation position of the laser light is performed (step S18). Subsequently, the Z height is set based on the set recipe (step S19).
- a modified layer forming process for forming a modified layer for dividing the object 100 is performed (step S20). Specifically, the control unit 9 controls the light source 82 and the moving mechanism so that the modified layer 112 is formed inside the object 100 whose back surface 100b (irradiation surface) is irradiated with the laser beam L2. 6 is controlled (see FIG. 20(e)). Finally, the object 100, which is a wafer, is taken out from the laser processing apparatus 1 (step S21). [Another example of processing by laser processing equipment (surface laser grooving + stealth dicing)]
- the surface laser grooving here is a process of removing the surface layer of the dicing streets on the surface 100a before the modified layer forming process.
- the surface layer is the TEG or film on the dicing street.
- the bottom surface of the grooves formed on the surface 100a may be roughened by the surface laser grooving.
- stealth dicing cannot be performed from the front surface 100a after the front surface laser grooving, and it is necessary to transfer to the back surface 100b once and irradiate the laser beam for forming the modified layer from the back surface 100b.
- the problem is that the transfer cost increases. Therefore, in this embodiment, the surface 100a of the object 100 is flattened by laser annealing after the surface laser grooving and before the modified layer forming process.
- FIG. 21 is a diagram for explaining laser grooving and flattening treatment and modified layer forming treatment after laser grooving.
- FIG. 21(a) first, an object 100 is prepared and supported by the support section 7 (see FIG. 1). Subsequently, as shown in FIG. 21(b), the movement mechanism 6 controlled by the controller 9 moves the laser beam L4 for surface laser grooving along one line extending in one direction on the surface 100a.
- the laser processing head 10A is moved so that the focal point is positioned, and a light source 81 (for example, a light source that emits an ultrashort pulse laser) controlled by the controller 9 outputs a laser beam L4 for surface laser grooving.
- a light source 81 for example, a light source that emits an ultrashort pulse laser
- control unit 9 performs the second grooving control to control the light source 81 and the moving mechanism 6 so that the surface layer of the surface 100a is removed by irradiating the surface 100a of the object 100 with the laser beam L4.
- the second grooving control is control related to the second grooving step (surface laser grooving) of removing the surface layer of the surface 100a by irradiating the surface of the object 100 with the laser beam L4.
- the bottom surface 100z of the groove on which the surface laser grooving is performed becomes a rough surface.
- the moving mechanism 6 controlled by the controller 9 moves the laser processing head so that the focal point of the laser beam L1 is positioned along the bottom surface 100z of the groove. 10B is moved, and the light source 82 controlled by the controller 9 outputs the laser beam L1 related to the laser annealing.
- the light source 82 here is, for example, a light source that emits a nanosecond pulse laser. That is, the control unit 9 irradiates the bottom surface 100z of the groove on the surface 100a of the object 100 with the laser beam L1 and causes the bottom surface 100z to become a laser annealing line 100x flattened by laser annealing. A first control for controlling the mechanism 6 is performed.
- the first control is control related to the first step (planarization process) of irradiating the surface 100a with the laser beam L1 and planarizing the surface 100a by laser annealing.
- the bottom surface 100z of the groove formed in the surface 100a by the surface laser grooving (second grooving) step is irradiated with the laser beam L1 as an irradiation surface to flatten the bottom surface 100z of the groove (laser annealing line 100x). I do.
- the moving mechanism 6 controlled by the controller 9 moves the laser processing head 10B so that the focal point of the laser beam L2 is positioned along the laser annealing line 100x.
- the light source 82 moved and controlled by the control unit 9 outputs the laser light L2 for forming the modified layer.
- the light source 82 here is, for example, a light source that emits a nanosecond pulse laser.
- the control unit 9 controls the light source 82 and the moving mechanism 6 so that a modified layer is formed inside the object 100 where the planarized bottom surface 100z (that is, the laser annealing line 100x) is irradiated with the laser beam L2. 2nd control to carry out.
- the second control is a second step (modified layer formation process ). After the modified layer is formed in this manner, an expanding process (FIG. 21(e)) is performed in the dividing step, and the object 100 is cut into a plurality of chips.
- the light source 81 for the surface laser grooving and the light source 82 for the flattening treatment are separately provided, but the present invention is not limited to this, and the light source for the surface laser grooving and the light source for the flattening treatment are shared.
- a light source that emits an ultrashort pulse laser For example, when a light source for surface laser grooving and a light source for flattening treatment are separately provided, the laser dicer for surface laser grooving and the laser dicer for flattening treatment and modified layer forming treatment are common. may be provided as a separate device.
- FIG. 22 is a flow chart showing a laser processing method including laser grooving, planarization, and modified layer formation.
- FIG. 23 is a diagram schematically showing an example of laser grooving, planarization treatment after laser grooving, and modified layer formation treatment. An example of processing in which an apparatus for surface laser grooving and an apparatus for flattening treatment and modified layer forming treatment are separate apparatuses will be described below.
- the light source for surface laser grooving is a common light source that emits an ultrashort pulse laser, and is described as the above-described "light source 81".
- the light source for the flattening process and the modified layer forming process is a light source of a device different from the device for the surface laser grooving, it is referred to as a "light source 82" for convenience of explanation.
- an object 100 which is a wafer, is put into a device related to surface laser grooving in the laser processing device 1 (step S101).
- the object 100 is set so that the rear surface 100b can be irradiated with laser light (see FIG. 23(a)).
- alignment of the irradiation position of the laser light is performed (step S102).
- surface laser grooving is performed to remove surface layers such as wiring and metal films on the surface 100a (step S103).
- the controller 9 controls the light source 81 and the moving mechanism 6 so that the surface 100a of the object 100 is irradiated with the laser beam L4 to remove the surface layer of the surface 100a.
- the target object 100 which is a wafer for which the processes up to step S104 have been completed, is put into the apparatus related to the planarization process and the modified layer forming process in the laser processing apparatus 1 (step S105). Then, alignment of the irradiation position of the laser light is performed (step S106). Subsequently, the Z height is set based on the set recipe (step S107).
- a flattening process is performed (step S108). Specifically, the control unit 9 irradiates the bottom surface 100z of the groove on the surface 100a of the object 100 with the laser beam L1, and the light source is controlled so that the bottom surface 100z becomes a laser annealing line 100x that is flattened by laser annealing. 82 and moving mechanism 6 are controlled. In the planarization process, all the laser annealing lines 100x are sequentially formed line by line (see FIG. 23(c)).
- a modified layer forming process for forming a modified layer for dividing the object 100 is performed (step S109). Specifically, the light source 82 is controlled by the controller 9 so that the modified layer 112 is formed inside the object 100 where the flattened bottom surface 100z (that is, the laser annealing line 100x) is irradiated with the laser beam L2. and the moving mechanism 6 is controlled (see FIG. 23(d)). Finally, the object 100, which is a wafer, is taken out from the laser processing apparatus 1 (step S110).
- the surface laser grooving and flattening treatment it has been described that the surface laser grooving is performed on all lines and then the flattening treatment is performed on each line, but the present invention is not limited to this. That is, the surface laser grooving and flattening treatment are performed for each line to remove the surface layer and roughen the bottom surface 100z (after FIG. 23(e), the bottom surface 100z is flattened).
- the process to form the laser annealing line 100x may be repeatedly performed, and the flattening process after surface laser grooving may be performed for all lines (see FIG. 23(g)).
- the surface laser grooving and the flattening process may be performed in the same apparatus, and the object that has been flattened may be subjected to the modified layer forming process in another apparatus. may be carried out on the apparatus of
- the front surface 100a or the back surface 100b of the object 100 having the functional element layer on the front surface 100a side is irradiated with the laser beam L1, and the irradiated surface is flattened by laser annealing. and a second step of irradiating the irradiation surface flattened in the first step with the laser beam L2 to form a modified layer inside the object 100.
- the pulse pitch is shorter than the pulse pitch of the laser light L2.
- the irradiated surface of the laser beam L2 is subjected to laser annealing.
- a laser beam L1 is applied for planarization. If the surface irradiated with the laser beam L2 when forming the modified layer is rough and not flat, the modified layer may not be properly formed by irradiation with the laser beam L2.
- the laser beam L1 for flattening the irradiated surface is irradiated in advance to the irradiated surface when forming the modified layer (laser annealing is performed), it becomes possible to irradiate the flattened irradiation surface with the laser light L2, and the modified layer can be appropriately formed inside the object 100.
- the pulse pitch of the laser beam L1 for laser annealing is shorter than the pulse pitch of the laser beam L2 for forming the modified layer.
- the material is recrystallized and flattened after melting.
- the regions can be formed continuously, and the irradiation surface can be more appropriately planarized by laser annealing.
- the irradiated surface of the object 100 can be appropriately planarized, and the modified layer can be appropriately formed inside the object 100 .
- the laser light L1 and the laser light L2 may be emitted from a common light source. According to such a configuration, the configuration related to laser processing can be simplified, and the size reduction of the device configuration can be realized.
- the frequency of the laser beam L1 may be higher than the frequency of the laser beam L2.
- the next laser beam L1 is irradiated before the irradiated area cools down, thereby accumulating heat and appropriately recrystallizing the irradiated area, thereby flattening the irradiated surface. can be done.
- the frequency of the laser light L1 for example, making it higher than the frequency of the laser light L2
- the number of branches in the processing progress direction of the laser light L1 may be greater than the number of branches in the processing progress direction of the laser light L2. Since the laser beam L1 has a large number of branches in the processing progress direction (for example, the number of branches is larger than that of the laser beam L2), the time required for the laser annealing process can be shortened.
- the number of branches in the direction that intersects the processing progress direction and is parallel to the irradiation surface of the laser beam L1 is the direction that intersects the processing progress direction of the laser beam L2 and is in the irradiation surface. It may be more than the number of branches in parallel directions. Thereby, the width flattened by the laser annealing treatment can be increased.
- the irradiation ranges of the beams of the laser beam L1 may partially overlap each other on the irradiation surface. Thereby, planarization can be performed even if the energy per point is low.
- unevenness occurs between the center of the beam and a location away from the center of the beam.
- the illuminated surface can be flattened.
- the laser beam L1 may be a top hat-shaped laser beam.
- the laser annealing region can be widened on the irradiation surface.
- the irradiation surface can be made flatter.
- the irradiation surface in the first step, may be irradiated with the laser beam L1 so as to planarize the irradiation surface and form a modified layer inside the object 100 .
- the laser beam L1 related to laser annealing for planarization also for forming the modified layer for example, the number of passes of the laser beam L2 related to formation of the modified layer can be reduced, and the modification can be performed.
- the time required for layer formation can be shortened.
- the irradiation surface may be irradiated with the laser beam L1 so that no modified layer is formed inside the object 100 .
- the irradiation surface may be irradiated with the laser beam L1 so that no modified layer is formed inside the object 100 .
- the focal point of the laser beam L1 may be positioned outside the object 100 . Accordingly, it is possible to appropriately avoid formation of a modified layer inside the object 100 by the laser beam L1 related to laser annealing.
- the back surface 100b may be irradiated with the laser light L1 to planarize the back surface 100b.
- the back surface 100b of the object 100 may have, for example, a satin finish or may be rough.
- the laser beam L2 is absorbed or scattered on the rear surface 100b, and the inside of the object 100 is appropriately modified. It may not be possible to form a solid layer.
- the roughened back surface 100b is appropriately flattened, and a modified layer is appropriately formed inside the object 100. can be done.
- the laser processing method further includes a first grooving step of forming a weakened region 100y on the front surface 100a by irradiating the laser beam L3 from the back surface 100b of the object 100 before the second step.
- the back surface 100b before the first grooving step may be irradiated with the laser beam L1 to planarize the back surface 100b.
- the laser beam L2 for forming the modified layer is irradiated to the rear surface 100b in the second step, thereby weakening the weakened region 100y. Using this, it is possible to appropriately form a crack reaching the surface 100a side on which the functional element layer is formed.
- the first grooving step when the first grooving step is performed, if the back surface 100b on which the laser beam L3 is incident is damaged, it is difficult to appropriately perform grooving (IR grooving) on the front surface 100a side. energy is limited.
- the first step relating to laser annealing is performed with the back surface 100b as the irradiation surface before the first grooving step, the first grooving step is performed in a state in which the back surface 100b is flattened. , the amount of energy that can be applied to the laser beam L3 in the first grooving step increases, and the types of target objects 100 (devices) that can be handled increase. Thereby, grooving (IR grooving) on the front surface 100a side can be performed more easily and appropriately.
- the laser processing method further includes a second grooving step of removing the surface layer of the surface 100a by irradiating the surface 100a of the object 100 with the laser beam L4.
- the bottom surface 100z of the formed groove may be irradiated with the laser beam L1 to planarize the bottom surface 100z of the groove.
- the surface 100a is irradiated with the laser beam L2 related to the formation of the modified layer in the second step, thereby improving the processing throughput and processing such as film peeling. Reduction in quality can be suppressed.
- the bottom surface 100z of the groove formed in the surface 100a by grooving is rough.
- the stealth dicing cannot be performed from the front surface 100a after grooving, and the laser beam L2 for forming the modified layer is irradiated from the rear surface 100b side after transferring to the rear surface 100b side.
- the problem is that the transfer cost is high.
- the first step related to laser annealing is performed with the bottom surface 100z of the groove formed on the surface 100a as the irradiation surface, so that the bottom surface 100z of the groove formed on the surface 100a is flat. Therefore, the stealth dicing process can be performed from the front surface 100a, which is the grooving surface side, and the transfer process described above becomes unnecessary. This makes it possible to speed up processing and reduce costs.
- SYMBOLS 1 Laser processing apparatus, 7... Support part, 9... Control part, 81, 82... Light source, 100... Object, 100a... Front surface, 100b... Back surface, 100y... Weakened area, 100z... Bottom surface, L1... Laser beam, L2 ...laser light.
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Abstract
Description
[レーザ加工装置の構成]
[レーザ加工ヘッドの構成]
[レーザ加工装置による加工の一例(ステルスダイシング)]
[レーザ加工装置による加工の他の例(IRグルービング+ステルスダイシング)]
[レーザ加工装置による加工の他の例(表面レーザグルービング+ステルスダイシング)]
Claims (17)
- 表面側に機能素子層を有する対象物の表面又は裏面に第1レーザ光を照射し、レーザアニールにより照射面の平坦化を行う第1工程と、
前記第1工程において平坦化された前記照射面に第2レーザ光を照射し、前記対象物の内部に改質層を形成する第2工程と、を含み、
前記第1レーザ光のパルスピッチは、前記第2レーザ光のパルスピッチよりも短い、レーザ加工方法。 - 前記第1レーザ光及び前記第2レーザ光は、共通の光源から出射されている、請求項1記載のレーザ加工方法。
- 前記第1レーザ光の周波数は、前記第2レーザ光の周波数よりも高い、請求項1又は2記載のレーザ加工方法。
- 前記第1レーザ光の加工進行方向における分岐数は、前記第2レーザ光の前記加工進行方向における分岐数よりも多い、請求項1~3のいずれか一項記載のレーザ加工方法。
- 前記第1レーザ光の、加工進行方向に交差する方向であって前記照射面に平行な方向における分岐数は、前記第2レーザ光の、前記加工進行方向に交差する方向であって前記照射面に平行な方向における分岐数よりも多い、請求項1~4のいずれか一項記載のレーザ加工方法。
- 前記第1レーザ光の分岐した各ビームは、前記照射面において互いに照射範囲の一部が重なっている、請求項4又は5記載のレーザ加工方法。
- 前記第1レーザ光は、トップハット形状のレーザ光である、請求項1~6のいずれか一項記載のレーザ加工方法。
- 前記第1工程では、前記照射面を平坦化すると共に前記対象物の内部に改質層が形成されるように、前記照射面に前記第1レーザ光を照射する、請求項1~7のいずれか一項記載のレーザ加工方法。
- 前記第1工程では、前記対象物の内部に改質層が形成されないように、前記照射面に前記第1レーザ光を照射する、請求項1~7のいずれか一項記載のレーザ加工方法。
- 前記第1工程では、前記第1レーザ光の集光点を前記対象物の外部の位置とする、請求項9記載のレーザ加工方法。
- 前記第1工程では、前記裏面を前記照射面として前記第1レーザ光を照射し、前記裏面の平坦化を行う、請求項1~10のいずれか一項記載のレーザ加工方法。
- 前記第2工程前において、前記対象物の前記裏面から第3レーザ光を照射することにより、前記表面に弱化領域を形成する第1グルービング工程を更に備え、
前記第1工程では、前記第1グルービング工程前の前記裏面を前記照射面として前記第1レーザ光を照射し、前記裏面の平坦化を行う、請求項11記載のレーザ加工方法。 - 前記対象物の前記表面に第4レーザ光を照射することにより、前記表面の表層を除去する第2グルービング工程を更に備え、
前記第1工程では、前記第2グルービング工程によって前記表面に形成された溝の底面を前記照射面として前記第1レーザ光を照射し、前記溝の底面の平坦化を行う、請求項1~10のいずれか一項記載のレーザ加工方法。 - 表面側に機能素子層を有する対象物を支持する支持部と、
前記対象物にレーザ光を照射する照射部と、
前記対象物の前記表面又は裏面に第1レーザ光が照射されてレーザアニールにより照射面が平坦化されるように前記照射部を制御する第1制御と、平坦化された前記照射面に前記第1レーザ光よりもパルスピッチが長い第2レーザ光が照射されて前記対象物の内部に改質層が形成されるように前記照射部を制御する第2制御と、を実施するように構成された制御部と、を備えるレーザ加工装置。 - 前記制御部は、前記第1制御において、前記裏面を前記照射面として前記第1レーザ光が照射され前記裏面が平坦化されるように前記照射部を制御する、請求項14記載のレーザ加工装置。
- 前記制御部は、
前記第2制御実施前において、前記対象物の前記裏面から第3レーザ光が照射されることにより前記表面に弱化領域が形成されるように前記照射部を制御する第1グルービング制御を更に実施し、
前記第1制御において、前記第1グルービング制御実施前の前記裏面を前記照射面として前記第1レーザ光が照射され前記裏面が平坦化されるように前記照射部を制御する、請求項15記載のレーザ加工装置。 - 前記制御部は、
前記対象物の前記表面に第4レーザ光が照射されることにより前記表面の表層が除去されるように前記照射部を制御する第2グルービング制御を更に実施し、
前記第1制御において、前記第2グルービング制御によって前記表面に形成された溝の底面を前記照射面として前記第1レーザ光が照射され前記溝の底面が平坦化されるように前記照射部を制御する、請求項14記載のレーザ加工装置。
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Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004361481A (ja) * | 2003-06-02 | 2004-12-24 | Sumitomo Heavy Ind Ltd | 均一照射装置及び照射方法 |
JP2012156168A (ja) * | 2011-01-21 | 2012-08-16 | Disco Abrasive Syst Ltd | 分割方法 |
JP2013130835A (ja) * | 2011-12-22 | 2013-07-04 | Sharp Corp | ホモジナイザ、ホモジナイザ装置および照明装置 |
JP2016525018A (ja) * | 2013-07-23 | 2016-08-22 | 3デー−ミクロマク アクチェンゲゼルシャフト | 平坦なワークピースを複数の部分に分割する方法及び装置 |
JP2017183401A (ja) * | 2016-03-29 | 2017-10-05 | 株式会社ディスコ | ウエーハの加工方法 |
JP2017208445A (ja) * | 2016-05-18 | 2017-11-24 | 株式会社ディスコ | レーザー加工装置及びレーザー加工方法 |
JP2019175976A (ja) * | 2018-03-28 | 2019-10-10 | パナソニックIpマネジメント株式会社 | 素子チップの製造方法 |
WO2020090893A1 (ja) * | 2018-10-30 | 2020-05-07 | 浜松ホトニクス株式会社 | レーザ加工方法 |
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Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004361481A (ja) * | 2003-06-02 | 2004-12-24 | Sumitomo Heavy Ind Ltd | 均一照射装置及び照射方法 |
JP2012156168A (ja) * | 2011-01-21 | 2012-08-16 | Disco Abrasive Syst Ltd | 分割方法 |
JP2013130835A (ja) * | 2011-12-22 | 2013-07-04 | Sharp Corp | ホモジナイザ、ホモジナイザ装置および照明装置 |
JP2016525018A (ja) * | 2013-07-23 | 2016-08-22 | 3デー−ミクロマク アクチェンゲゼルシャフト | 平坦なワークピースを複数の部分に分割する方法及び装置 |
JP2017183401A (ja) * | 2016-03-29 | 2017-10-05 | 株式会社ディスコ | ウエーハの加工方法 |
JP2017208445A (ja) * | 2016-05-18 | 2017-11-24 | 株式会社ディスコ | レーザー加工装置及びレーザー加工方法 |
JP2019175976A (ja) * | 2018-03-28 | 2019-10-10 | パナソニックIpマネジメント株式会社 | 素子チップの製造方法 |
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