WO2020130108A1 - Procédé d'usinage au laser et procédé de fabrication de dispositif à semi-conducteurs - Google Patents

Procédé d'usinage au laser et procédé de fabrication de dispositif à semi-conducteurs Download PDF

Info

Publication number
WO2020130108A1
WO2020130108A1 PCT/JP2019/049955 JP2019049955W WO2020130108A1 WO 2020130108 A1 WO2020130108 A1 WO 2020130108A1 JP 2019049955 W JP2019049955 W JP 2019049955W WO 2020130108 A1 WO2020130108 A1 WO 2020130108A1
Authority
WO
WIPO (PCT)
Prior art keywords
laser processing
modified spots
laser light
processing method
semiconductor
Prior art date
Application number
PCT/JP2019/049955
Other languages
English (en)
Japanese (ja)
Inventor
大祐 河口
陽太郎 和仁
泰則 伊ケ崎
Original Assignee
浜松ホトニクス株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 浜松ホトニクス株式会社 filed Critical 浜松ホトニクス株式会社
Publication of WO2020130108A1 publication Critical patent/WO2020130108A1/fr

Links

Images

Classifications

    • 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
    • B23K26/50—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
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • 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
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting

Definitions

  • the present disclosure relates to a laser processing method and a semiconductor device manufacturing method.
  • a modified region is formed inside the semiconductor object, and a crack extending from the modified region is propagated, so that the semiconductor object is a semiconductor such as a semiconductor wafer.
  • a processing method for cutting out a member is known (see, for example, Patent Documents 1 and 2).
  • the semiconductor member to be thinned may include an epitaxial growth layer for a semiconductor device to be cut out later.
  • the leaked light may damage the epitaxial growth layer, resulting in deterioration of the quality of the semiconductor device.
  • the present disclosure aims to provide a laser processing method and a semiconductor device manufacturing method that enable acquisition of a suitable semiconductor device.
  • a laser processing method is a laser processing method for cutting a semiconductor wafer along a virtual surface facing the surface of the semiconductor wafer inside the semiconductor wafer.
  • a modified spot is formed inside the semiconductor wafer by irradiation with laser light prior to forming a semiconductor layer for a semiconductor device by epitaxial growth. Therefore, the semiconductor layer cannot be damaged when the modified spot is formed. Therefore, it is possible to obtain a suitable semiconductor device in which damage is suppressed by advancing a crack extending from the modified spot and cutting (eg, peeling) the semiconductor wafer along the virtual surface.
  • the semiconductor is changed from a surface different from the surface on which the semiconductor layer is formed in the semiconductor wafer so that the converging point does not overlap the modified spot when viewed from the direction intersecting the surface.
  • a third step of forming a crack across the virtual surface by irradiating the inside of the wafer with laser light may be provided. As described above, the irradiation of the laser light may form a crack along the virtual surface that is the origin of the peeling. Even in this case, since the modified spot is formed prior to the formation of the semiconductor layer, the damage to the semiconductor layer is less likely to occur as compared with the case where all the laser processing is performed after the formation of the semiconductor layer. Suppressed.
  • a modified spot is formed along the virtual surface inside the semiconductor wafer by irradiation with laser light, and a crack extending from the modified spot is developed to cut out a semiconductor device from the semiconductor wafer (peeling).
  • peeling In order to reduce the unevenness of the peeled surface and obtain a more suitable semiconductor device, it is effective to reduce the energy of the laser light on the virtual surface. If the energy on the virtual surface is too low, modified spots and cracks cannot be generated.
  • the present inventor has obtained the following knowledge by paying attention to such a problem and proceeding with further studies. That is, first, by irradiating a semiconductor wafer containing gallium with a laser beam, a plurality of modified spots and a deposition region containing gallium deposited in the plurality of modified spots are provided along the virtual surface. Form. Then, when the laser light is irradiated again in a later step, the modification spots formed in advance do not overlap the condensing point of the laser light, and the energy of the laser light on the virtual surface is set to the processing threshold of the semiconductor wafer. The region containing pre-formed gallium can be expanded even if the amount is lowered below the range. As a result, when the semiconductor wafer is peeled off by forming a crack across the virtual surface, the unevenness of the peeled surface can be reduced.
  • the following invention was made based on such knowledge.
  • the semiconductor wafer contains gallium
  • a plurality of modified spots and a plurality of modified spots are formed by irradiating the inside of the semiconductor wafer with laser light from the surface.
  • Forming a plurality of deposition regions containing gallium deposited in the modified spots and in the third step, irradiating the inside of the semiconductor wafer with laser light so that the energy on the virtual surface falls below the processing threshold of the semiconductor wafer.
  • the precipitation region may be enlarged and a crack may be formed across the virtual surface.
  • a plurality of modified spots and deposited gallium are formed along a virtual surface facing the surface that is the incident surface of laser light. Forming a plurality of deposition regions including. Then, in a later step, the inside of the semiconductor wafer is irradiated with laser light so that the condensing point does not overlap with the modified spot and the energy on the virtual surface falls below the processing threshold of the semiconductor wafer. Expand the area and create a crack across the virtual plane. As a result, as described above, it becomes possible to obtain a suitable semiconductor device in which unevenness is reduced due to peeling at the boundary of the crack across the virtual surface.
  • the second step by heating the semiconductor wafer for epitaxial growth, a plurality of cracks respectively extending from the plurality of modified spots are propagated to form a crack across the virtual surface. You may. In this case, the formation of the semiconductor layer and the formation of the crack over the virtual surface can be performed at the same time.
  • the semiconductor wafer in the first step, may be provided with a peripheral region that prevents the development of a plurality of cracks extending from the plurality of modified spots. In this case, during the epitaxial growth in the second step, unintentional formation of cracks across the imaginary plane and peeling are suppressed.
  • the laser processing method includes a fourth step between the first step and the second step, which measures the transmittance of the semiconductor wafer, and a fourth step between the fourth step and the second step.
  • the modified spots can be sufficiently formed inside the semiconductor wafer prior to the second step of forming the semiconductor layer.
  • a plurality of modified spots may be formed so that the plurality of cracks extending from the plurality of modified spots are not connected to each other.
  • the focus point of the laser light can be prevented from overlapping not only with the modified spot but also with the crack extending from the modified spot.
  • a plurality of rows of modified spots are formed as a plurality of modified spots by moving the focal point of the pulsed laser light along the virtual surface.
  • the condensing point of the pulsed laser light may be moved along the virtual plane between the rows of the reforming spots of a plurality of rows. In this case, it is possible to reliably prevent the converging points of the laser light in the third step from overlapping the plurality of modified spots.
  • the semiconductor wafer may contain gallium nitride.
  • the pressure (internal pressure) of the nitrogen gas generated along with the deposition of gallium can be used to easily form a crack over the virtual surface.
  • a semiconductor device manufacturing method includes a step of performing any one of the above laser processing methods, and a step of acquiring a plurality of semiconductor devices from a semiconductor wafer with a crack across a virtual surface as a boundary. This method implements the laser processing method described above. Therefore, a suitable semiconductor device can be obtained for the same reason.
  • a plurality of virtual planes may be set so as to be aligned in the direction along the surface.
  • a plurality of semiconductor devices can be acquired from one semiconductor wafer.
  • FIG. 3 is a plan view of the GaN ingot shown in FIG. 2. It is a longitudinal cross-sectional view of a part of the GaN ingot in one step of the laser processing method and the semiconductor member manufacturing method of the first example. It is a transverse cross section of a part of GaN ingot in one process of the laser processing method and semiconductor member manufacturing method of the 1st example. It is a longitudinal cross-sectional view of a part of the GaN ingot in one step of the laser processing method and the semiconductor member manufacturing method of the first example.
  • FIG. 6 is an image of modified spots and cracks formed by the laser processing method and the semiconductor member manufacturing method of the second and third embodiments. It is a top view of a GaN wafer which is an object of a laser processing method and a semiconductor member manufacturing method of the 2nd example. It is a side view of a part of GaN wafer in one process of a laser processing method and a semiconductor member manufacturing method of a 2nd example. It is a side view of a part of GaN wafer in one process of a laser processing method and a semiconductor member manufacturing method of a 2nd example. It is a side view of a semiconductor device in one process of a laser processing method and a semiconductor member manufacturing method of a 2nd example.
  • the laser processing apparatus 1 includes a stage 2, a light source 3, a spatial light modulator 4, a condenser lens 5, and a control unit 6.
  • the laser processing apparatus 1 is an apparatus that forms a modified region 12 on the object 11 by irradiating the object 11 with a laser beam L.
  • the first horizontal direction will be referred to as the X direction
  • the second horizontal direction perpendicular to the first horizontal direction will be referred to as the Y direction.
  • the vertical direction is called the Z direction.
  • the stage 2 supports the target object 11 by, for example, adsorbing a film attached to the target object 11.
  • the stage 2 is movable along each of the X direction and the Y direction. Further, the stage 2 can rotate about an axis parallel to the Z direction as a center line.
  • the light source 3 outputs a laser beam L that is transparent to the object 11 by using, for example, a pulse oscillation method.
  • the spatial light modulator 4 modulates the laser light L output from the light source 3.
  • the spatial light modulator 4 is, for example, a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) spatial light modulator (SLM: Spatial Light Modulator).
  • the condenser lens 5 condenses the laser light L modulated by the spatial light modulator 4.
  • the spatial light modulator 4 and the condenser lens 5 are movable as a laser irradiation unit along the Z direction.
  • the modified region 12 is a region in which density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding unmodified region.
  • the modified region 12 includes, for example, a melt-processed region, a crack region, a dielectric breakdown region, and a refractive index change region.
  • a plurality of modified spots 13 are moved along the X direction by 1. It is formed so as to line up in a row.
  • One modified spot 13 is formed by irradiation with one pulse of laser light L.
  • the one-row reforming region 12 is a set of a plurality of reforming spots 13 arranged in one row.
  • the adjacent modified spots 13 may be connected to each other or may be separated from each other depending on the relative moving speed of the condensing point C with respect to the object 11 and the repetition frequency of the laser light L.
  • the control unit 6 controls the stage 2, the light source 3, the spatial light modulator 4, and the condenser lens 5.
  • the control unit 6 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like.
  • the software (program) read into the memory or the like is executed by the processor, and the reading and writing of data in the memory and the storage and the communication by the communication device are controlled by the processor. Thereby, the control unit 6 realizes various functions.
  • the target 11 is a GaN ingot (semiconductor ingot, semiconductor target) 20 formed of gallium nitride (GaN) in a disk shape, for example.
  • the GaN ingot 20 has a diameter of 2 inches and the GaN ingot 20 has a thickness of 2 mm.
  • the laser processing method and the semiconductor member manufacturing method of the first embodiment are performed to cut out a plurality of GaN wafers (semiconductor wafers, semiconductor members) 30 from the GaN ingot 20.
  • the GaN wafer 30 has a diameter of 2 inches and the GaN wafer 30 has a thickness of 100 ⁇ m.
  • the laser processing apparatus 1 described above forms a plurality of modified spots 13 along each of a plurality of virtual surfaces 15.
  • Each of the plurality of virtual surfaces 15 is a surface facing the surface 20a of the GaN ingot 20 inside the GaN ingot 20, and is set to be aligned in a direction facing the surface 20a.
  • each of the plurality of virtual surfaces 15 is a surface parallel to the surface 20a and has, for example, a circular shape.
  • Each of the plurality of virtual surfaces 15 is set so as to overlap each other when viewed from the front surface 20a side.
  • a plurality of peripheral regions 16 are set in the GaN ingot 20 so as to surround each of the plurality of virtual surfaces 15.
  • each of the plurality of virtual surfaces 15 does not reach the side surface 20b of the GaN ingot 20.
  • the distance between the adjacent virtual surfaces 15 is 100 ⁇ m
  • the width of the peripheral region 16 in the present embodiment, the distance between the outer edge of the virtual surface 15 and the side surface 20b is 30 ⁇ m or more.
  • the formation of the plurality of modified spots 13 is sequentially performed for each one virtual surface 15 from the side opposite to the surface 20a by the irradiation of the laser light L having a wavelength of 532 nm, for example. Since the formation of the plurality of modified spots 13 is the same on each of the plurality of virtual surfaces 15, the formation of the plurality of modified spots 13 along the virtual surface 15 closest to the surface 20a will be described below with reference to FIGS. This will be described in detail with reference to 11.
  • the arrow indicates the locus of the condensing point C of the laser light L.
  • the modified spots 13a, 13b, 13c, 13d described later may be collectively referred to as the modified spot 13
  • the cracks 14a, 14b, 14c, 14d described later may be collectively referred to as the crack 14.
  • the laser processing apparatus 1 causes the laser light L to enter the GaN ingot 20 from the surface 20 a and irradiate the laser light L along the virtual plane 15 (for example, a virtual plane).
  • a plurality of modified spots 13a are formed (two-dimensionally arranged along the entire surface 15) (step S1).
  • the laser processing apparatus 1 forms the plurality of modified spots 13a so that the plurality of cracks 14a extending from the plurality of modified spots 13a are not connected to each other.
  • the laser processing apparatus 1 forms the modified spots 13a in a plurality of rows by moving the condensing point C of the pulsed laser light L along the virtual surface 15.
  • the modified spot 13a is shown in white (no hatching), and the range in which the crack 14a extends is shown by broken lines (the same applies to FIGS. 6 to 11). Further, at this time, the gallium deposited in each of the modified spots 13a spreads so as to enter the crack 14a, so that a deposition region R containing the deposited gallium is formed around the modified spot 13a. ..
  • the pulsed laser light L is modulated by the spatial light modulator 4 so as to be condensed at a plurality of (for example, six) condensing points C arranged in the Y direction. Then, the plurality of condensing points C are relatively moved on the virtual surface 15 along the X direction.
  • the distance between the condensing points C adjacent to each other in the Y direction is 8 ⁇ m
  • the pulse pitch of the laser light L that is, the relative moving speed of the plurality of condensing points C is determined by the repetition frequency of the laser light L).
  • the divided value is 10 ⁇ m.
  • the pulse energy of the laser light L per one condensing point C (hereinafter, simply referred to as “pulse energy of the laser light L”) is 0.33 ⁇ J.
  • the center-to-center distance between adjacent modified spots 13a in the Y direction is 8 ⁇ m
  • the center-to-center distance between adjacent modified spots 13a in the X direction is 10 ⁇ m.
  • the cracks 14a extending from the modified spots 13a are not connected to each other.
  • the laser processing apparatus 1 causes the laser light L to enter the GaN ingot 20 from the surface 20 a and irradiates the laser light L along the virtual surface 15 (for example, A plurality of modified spots (second modified spots) 13b are formed so as to be arranged two-dimensionally along the entire virtual surface 15 (step S2). At this time, the laser processing apparatus 1 forms the plurality of modified spots 13b so as not to overlap the plurality of modified spots 13a and the plurality of cracks 14a.
  • the laser processing apparatus 1 moves the condensing point C of the pulsed laser light L along the virtual plane 15 between the rows of the reforming spots 13a of the plurality of rows to thereby form the reforming spots 13b of the plurality of rows.
  • the cracks 14b extending from the modified spots 13b may be connected to the cracks 14a. 6 and 7, the modified spot 13b is shown by dot hatching, and the range in which the crack 14b extends is shown by broken lines (the same applies to FIGS. 8 to 11).
  • the gallium deposited in each of the modified spots 13b spreads so as to enter the crack 14b, so that a deposition region R containing the deposited gallium is formed around the modified spot 13b. ..
  • the pulsed laser light L is modulated by the spatial light modulator 4 so as to be condensed at a plurality of (for example, six) condensing points C arranged in the Y direction. Then, the plurality of condensing points C are relatively moved on the virtual surface 15 along the X direction at the centers between the rows of the reformed spots 13a.
  • the distance between the condensing points C adjacent to each other in the Y direction is 8 ⁇ m
  • the pulse pitch of the laser light L is 10 ⁇ m.
  • the pulse energy of the laser light L is 0.33 ⁇ J.
  • the center-to-center distance between adjacent modified spots 13b in the Y direction is 8 ⁇ m
  • the center-to-center distance between adjacent modified spots 13b in the X direction is 10 ⁇ m.
  • the laser processing apparatus 1 causes the laser light L to enter the GaN ingot 20 from the surface 20 a and irradiate the laser light L along the virtual surface 15 (for example, A plurality of modified spots (third modified spots) 13c are formed so as to be two-dimensionally arranged along the entire virtual surface 15 (step S3). Further, as shown in FIGS. 10 and 11, the laser processing apparatus 1 causes the laser light L to enter the GaN ingot 20 from the front surface 20 a and irradiate the laser light L along the virtual surface 15 (for example, a virtual surface). A plurality of modified spots (third modified spots) 13d are formed so as to be two-dimensionally arranged along the entire surface 15 (step S4). At this time, the laser processing apparatus 1 forms the plurality of modified spots 13c and 13d so as not to overlap the plurality of modified spots 13a and 13b.
  • the laser processing apparatus 1 moves the condensing point C of the pulsed laser light L along the virtual plane 15 between the rows of the reforming spots 13a and 13b of the plurality of rows, thereby reforming the plurality of rows.
  • the spots 13c and 13d are formed.
  • the cracks 14c and 14d extending from the modified spots 13c and 13d may be connected to the cracks 14a and 14b.
  • the modified spot 13c is shown by solid line hatching, and the range in which the crack 14c extends is shown by broken lines (also in FIGS. 10 and 11).
  • the modified spot 13d is shown by solid line hatching (solid line hatching that is the reverse of the solid line hatching of the modified spot 13c), and the range in which the crack 14d extends is shown by broken lines.
  • the gallium deposited in each of the reformed spots 13c and 13d spreads so as to enter the cracks 14c and 14d, so that the deposited gallium is deposited around the reformed spots 13c and 13d. Region R is formed.
  • the pulsed laser light L is modulated by the spatial light modulator 4 so as to be condensed at a plurality of (for example, six) condensing points C arranged in the Y direction. Then, the plurality of converging points C are relatively moved on the virtual surface 15 along the X direction at the center between the rows of the reformed spots 13a and 13b of the plurality of rows.
  • the distance between the condensing points C adjacent to each other in the Y direction is 8 ⁇ m
  • the pulse pitch of the laser light L is 5 ⁇ m.
  • the pulse energy of the laser light L is 0.33 ⁇ J.
  • the center-to-center distance between adjacent modified spots 13c in the Y direction is 8 ⁇ m
  • the center-to-center distance between adjacent modified spots 13c in the X direction is 5 ⁇ m.
  • the center-to-center distance between the modified spots 13d adjacent to each other in the Y direction is 8 ⁇ m
  • the center-to-center distance between the modified spots 13d adjacent to each other in the X-direction is 5 ⁇ m.
  • a heating device including a heater or the like heats the GaN ingot 20 to connect the plurality of cracks 14 extending from the plurality of modified spots 13 to each other on each of the plurality of virtual planes 15, thereby being shown in FIG.
  • a crack 17 (hereinafter, simply referred to as “crack 17”) that extends over the virtual surface 15 is formed in each of the plurality of virtual surfaces 15.
  • a range in which the plurality of modified spots 13, the plurality of cracks 14, and the crack 17 are formed is shown by a broken line.
  • the cracks 17 may be formed by connecting the plurality of cracks 14 to each other by applying some force to the GaN ingot 20 by a method other than heating. Further, by forming the plurality of modified spots 13 along the virtual surface 15, the plurality of cracks 14 may be connected to each other to form the crack 17.
  • the GaN ingot 20 nitrogen gas is generated in a plurality of cracks 14 extending from the plurality of modified spots 13, respectively. Therefore, by heating the GaN ingot 20 and expanding the nitrogen gas, the crack 17 can be formed by utilizing the pressure (internal pressure) of the nitrogen gas. Moreover, since the peripheral region 16 prevents the cracks 14 from propagating to the outside of the virtual surface 15 surrounded by the peripheral region 16 (for example, the side surface 20b of the GaN ingot 20), nitrogen generated in the cracks 14 is prevented. It is possible to prevent the gas from escaping to the outside of the virtual surface 15.
  • the peripheral area 16 is a non-modified area that does not include the modified spot 13, and when the crack 17 is formed on the virtual surface 15 surrounded by the peripheral area 16, the virtual surface 15 surrounded by the peripheral area 16 is formed. It is a region that prevents the plurality of cracks 14 from propagating to the outside. Therefore, the width of the peripheral region 16 can be set to 30 ⁇ m or more.
  • the grinding device grinds (polishs) the portions of the GaN ingot 20 corresponding to the plurality of peripheral regions 16 and the plurality of virtual surfaces 15, respectively, so that a plurality of cracks 17 are formed as shown in FIG.
  • a plurality of GaN wafers 30 are obtained from the GaN ingot 20 with each of them as a boundary (step S5). In this way, the GaN ingot 20 is cut along each of the virtual surfaces 15.
  • portions of the GaN ingot 20 corresponding to the plurality of peripheral regions 16 may be removed by mechanical processing other than grinding, laser processing, or the like.
  • the laser processing method of the first example includes up to the step of forming the plurality of modified spots 13 along each of the plurality of virtual surfaces 15. Further, among the above steps, the steps up to the step of obtaining the plurality of GaN wafers 30 from the GaN ingot 20 with each of the plurality of cracks 17 as the boundary are the semiconductor member manufacturing method of the first example.
  • the plurality of modified spots 13a are formed along each of the plurality of virtual surfaces 15 so as not to overlap the plurality of modified spots 13a and the plurality of cracks 14a. Then, a plurality of modified spots 13b are formed along each of the plurality of virtual surfaces 15. Furthermore, in the laser processing method of the first example, a plurality of modified spots 13c and 13d are formed along each of the plurality of virtual surfaces 15 so as not to overlap the plurality of modified spots 13a and 13b. Thereby, the plurality of modified spots 13 can be accurately formed along each of the plurality of virtual surfaces 15, and as a result, the crack 17 can be formed accurately along each of the plurality of virtual surfaces 15. It will be possible.
  • the laser processing method of the first example it is possible to obtain a plurality of suitable GaN wafers 30 by obtaining a plurality of GaN wafers 30 from the GaN ingot 20 with each of the plurality of cracks 17 as a boundary. ..
  • the laser processing apparatus 1 that implements the laser processing method of the first example, it is possible to accurately form the crack 17 along each of the plurality of virtual surfaces 15, and thus a plurality of suitable GaN layers can be formed.
  • the wafer 30 can be acquired.
  • the plurality of modified spots 13a are formed so that the plurality of cracks 14a extending from the plurality of modified spots 13a are not connected to each other. Thereby, the plurality of modified spots 13b can be formed more accurately along the virtual surface 15.
  • the condensing point C of the pulsed laser light L is moved along the virtual surface 15 to form the modified spots 13a in a plurality of rows and pulsed.
  • the plurality of rows of modified spots 13b are formed.
  • gallium nitride contained in the material of the GaN ingot 20 is decomposed by the irradiation of the laser beam L, gallium is deposited in the cracks 14a extending from the modified spots 13a. Then, the deposition region R is formed, and the laser light L is easily absorbed by the gallium. Therefore, forming the plurality of modified spots 13b so as not to overlap the crack 14a is effective in accurately forming the plurality of modified spots 13b along the virtual surface 15.
  • the crack 17 can be easily formed by utilizing the pressure of the nitrogen gas.
  • the cracks 17 can be accurately formed along each of the virtual surfaces 15 by the steps included in the laser processing method of the first example.
  • the plurality of virtual surfaces 15 are set to be aligned in the direction facing the surface 20 a of the GaN ingot 20. This makes it possible to obtain a plurality of GaN wafers 30 from one GaN ingot 20.
  • FIG. 14 is an image of a peeled surface of a GaN wafer formed by the laser processing method and the semiconductor member manufacturing method of an example
  • FIGS. 15A and 15B show the height of the peeled surface shown in FIG. It is a profile.
  • laser light L having a wavelength of 532 nm is made incident on the inside of the GaN ingot 20 from the surface 20a of the GaN ingot 20, and one condensing point C arranged in the Y direction is placed on the virtual surface 15 along the X direction. Were relatively moved to form a plurality of modified spots 13 along the virtual surface 15.
  • the distance between adjacent condensing points C in the Y direction was 10 ⁇ m
  • the pulse pitch of the laser light L was 1 ⁇ m
  • the pulse energy of the laser light L was 1 ⁇ J.
  • irregularities of about 25 ⁇ m appeared on the separated surface (surface formed by the crack 17) of the GaN wafer 30.
  • FIG. 16 is an image of a peeled surface of a GaN wafer formed by a laser processing method and a semiconductor member manufacturing method of another example, and FIGS. 17(a) and 17(b) are shown in FIG. It is a height profile of a peeling surface.
  • laser light L having a wavelength of 532 nm is made to enter the inside of the GaN ingot 20 from the surface 20a of the GaN ingot 20, and the first and second steps of the laser processing method and the semiconductor member manufacturing method of the first embodiment.
  • the plurality of modified spots 13 were formed along the virtual surface 15.
  • the distance between the condensing points C adjacent to each other in the Y direction was 6 ⁇ m
  • the pulse pitch of the laser light L was 10 ⁇ k
  • the pulse energy of the laser light L was 0.33 ⁇ J.
  • the distance between the condensing points C adjacent to each other in the Y direction was 6 ⁇ m
  • the pulse pitch of the laser light L was 10 ⁇ m
  • the pulse energy of the laser light L was 0.33 ⁇ J.
  • the distance between the condensing points C adjacent to each other in the Y direction was 6 ⁇ m
  • the pulse pitch of the laser light L was 5 ⁇ m
  • the pulse energy of the laser light L was 0.33 ⁇ J.
  • the distance between the condensing points C adjacent to each other in the Y direction was 6 ⁇ m
  • the pulse pitch of the laser light L was 5 ⁇ m
  • the pulse energy of the laser light L was 0.33 ⁇ J.
  • unevenness of about 5 ⁇ m appeared on the separated surface of the GaN wafer 30.
  • the irregularities appearing on the separated surface of the GaN wafer 30 are small, that is, the cracks 17 along the virtual surface 15. Was found to be formed with high precision. It should be noted that if the irregularities appearing on the peeled surface of the GaN wafer 30 become small, the amount of grinding for flattening the peeled surface will be small. Therefore, it is advantageous in terms of material utilization efficiency and production efficiency that the irregularities appearing on the separated surface of the GaN wafer 30 become small.
  • a plurality of modified spots 13a are formed along a virtual surface 15, and the modified spots 13b are virtual so that the modified spots 13b overlap the cracks 14a extending from the modified spots 13a on one side.
  • a plurality of modified spots 13b are formed along the surface 15.
  • the laser light L is easily absorbed by the gallium deposited in the plurality of cracks 14a, even if the condensing point C is located on the virtual surface 15, the laser is not applied to the modified spot 13a.
  • the modified spot 13b is easily formed on the incident side of the light L.
  • a plurality of modified spots 13c are formed along the virtual surface 15 so that the modified spots 13c overlap the cracks 14b extending from the modified spots 13b on one side.
  • the laser light L is easily absorbed by the gallium deposited in the plurality of cracks 14b, even if the condensing point C is located on the virtual surface 15, the laser is not applied to the modified spot 13b.
  • the modified spot 13c is easily formed on the incident side of the light L.
  • the plurality of modified spots 13b are formed on the incident side of the laser light L with respect to the plurality of modified spots 13a, and further, the plurality of modified spots 13c are formed into the plurality of modified spots 13b. On the other hand, it tends to be formed on the incident side of the laser light L.
  • a plurality of modified spots 13a are formed along the virtual surface 15 so that the modified spots 13b do not overlap the cracks 14a extending from the modified spots 13a on both sides thereof.
  • a plurality of modified spots 13b are formed along the virtual surface 15.
  • the laser light L is easily absorbed by the gallium deposited in the plurality of cracks 14a, the modified spot 13b does not overlap the crack 14a, so the modified spot 13b is similar to the modified spot 13a.
  • a plurality of modified spots 13c are formed along the virtual surface 15 so that the modified spots 13c overlap the cracks 14a and 14b extending from the modified spots 13a and 13b on both sides thereof.
  • a plurality of modified spots 13d are formed along the virtual surface 15 so that the modified spots 13d overlap the cracks 14a and 14b extending from the modified spots 13a and 13b on both sides thereof.
  • the modified spots 13c and 13d are easily formed on the incident side of the laser light L with respect to 13b. As described above, in this example, the modified spots 13c and 13d are easily formed on the incident side of the laser light L with respect to the modified spots 13a and 13b.
  • a plurality of modified spots 13a and a plurality of modified spots 13a are provided so as not to overlap the cracks 14a extending from the modified spots 13a. It can be seen that the formation of the spots 13b is extremely important in reducing the unevenness appearing on the separated surface of the GaN wafer 30.
  • FIG. 20A and 20B are images of cracks formed during the laser processing method and the semiconductor member manufacturing method of an example
  • FIG. 20B is a rectangle in FIG. 20A. It is an enlarged image in the frame.
  • laser light L having a wavelength of 532 nm is made to enter the inside of the GaN ingot 20 from the surface 20a of the GaN ingot 20, and the six condensing points C arranged in the Y direction are arranged on the virtual surface 15 along the X direction. Were relatively moved to form a plurality of modified spots 13 along the virtual surface 15.
  • the distance between the condensing points C adjacent to each other in the Y direction was 6 ⁇ m
  • the pulse pitch of the laser light L was 1 ⁇ m
  • the pulse energy of the laser light L was 1.33 ⁇ J.
  • the laser processing was stopped in the middle of the virtual surface 15.
  • the crack that propagated from the processed region to the unprocessed region largely deviated from the virtual surface 15 in the unprocessed region.
  • FIG. 21(a) and 21(b) are images of cracks formed during the laser processing method and the semiconductor member manufacturing method of another example of the embodiment
  • FIG. 21(b) is an image of FIG. It is an enlarged image in a rectangular frame in (a).
  • laser light L having a wavelength of 532 nm is made to enter the inside of the GaN ingot 20 from the surface 20a of the GaN ingot 20, and the six condensing points C arranged in the Y direction are arranged on the virtual surface 15 along the X direction. Were relatively moved to form a plurality of modified spots 13 along the virtual surface 15.
  • the processing area 1 and the processing area 2 are set such that the distance between the condensing points C adjacent to each other in the Y direction is 6 ⁇ m, the pulse pitch of the laser light L is 10 ⁇ m, and the pulse energy of the laser light L is 0.33 ⁇ J.
  • a plurality of rows of modified spots 13 were formed on the surface. Then, the distance between the condensing points C adjacent to each other in the Y direction is 6 ⁇ m, the pulse pitch of the laser light L is 10 ⁇ m, and the pulse energy of the laser light L is 0.33 ⁇ J.
  • a plurality of rows of modified spots 13 were formed such that each row was positioned in the center between the plurality of rows of modified spots 13.
  • the distance between the condensing points C adjacent to each other in the Y direction is 6 ⁇ m
  • the pulse pitch of the laser light L is 5 ⁇ m
  • the pulse energy of the laser light L is 0.33 ⁇ J.
  • a plurality of rows of reforming spots 13 were formed such that each row was positioned at the center between the rows of reforming spots 13. In this case, as shown in (a) and (b) of FIG. 21, the crack propagated from the processing region 1 to the processing region 2 was not largely deviated from the virtual surface 15 in the processing region 2.
  • FIG. 22 is an image (side view image) of modified spots and cracks formed by the laser processing method and the semiconductor member manufacturing method of the comparative example.
  • a laser beam L having a wavelength of 532 nm is made incident on the inside of the GaN ingot 20 from the surface 20a of the GaN ingot 20, and one condensing point C is relatively moved on the virtual plane 15 along the X direction.
  • the plurality of modified spots 13 were formed along the imaginary plane 15 by moving the modified spots 13 to.
  • the distance between the condensing points C adjacent to each other in the Y direction is 2 ⁇ m
  • the pulse pitch of the laser light L is 5 ⁇ m
  • the pulse energy of the laser light L is 0.3 ⁇ J.
  • Quality spot 13 was formed.
  • the extension amount of the crack 14 extending from the modified spot 13 to the laser light L incident side and the opposite side was about 100 ⁇ m.
  • FIG. 23A and 23B are images of modified spots and cracks formed by the laser processing method and the semiconductor member manufacturing method of the first embodiment.
  • FIG. 23A is an image in plan view
  • FIG. I is an image in side view.
  • laser light L having a wavelength of 532 nm is made incident on the inside of the GaN ingot 20 from the surface 20a of the GaN ingot 20, and the six condensing points C arranged in the Y direction are virtual along the X direction.
  • a plurality of modified spots 13 were formed along the virtual surface 15.
  • the distance between the condensing points C adjacent to each other in the Y direction is 8 ⁇ m
  • the pulse pitch of the laser light L is 10 ⁇ m
  • the pulse energy of the laser light L is 0.3 ⁇ J.
  • the modified spot 13a of No. 1 was formed.
  • the distance between the converging points C adjacent in the Y direction is 8 ⁇ m
  • the pulse pitch of the laser light L is 10 ⁇ m.
  • a plurality of modified spots 13b were formed along the virtual surface 15 by setting the pulse energy of the laser light L to 0.3 ⁇ J.
  • the distance between the converging points C adjacent to each other in the Y direction is 8 ⁇ m, and the pulse pitch of the laser light L is changed.
  • a plurality of modified spots 13 were formed along the virtual surface 15 with the pulse energy of the laser beam L being 5 ⁇ m and 0.3 ⁇ J.
  • the distance between the converging points C adjacent in the Y direction is 8 ⁇ m, and the pulse pitch of the laser light L is 5 ⁇ m.
  • a plurality of modified spots 13 were formed along the virtual surface 15 with the pulse energy of the laser light L set to 0.3 ⁇ J.
  • the first modified spot 13a and the third modified spot 13 overlap each other, and the second modified spot 13b and the fourth modified spot 13 overlap each other. It is assumed that In this case, as shown in (b) of FIG. 23, the extension amount of the crack 14 extending from the modified spot 13 to the incident side of the laser light L and the opposite side thereof was about 70 ⁇ m.
  • 24A and 24B are images of modified spots and cracks formed by the laser processing method and the semiconductor member manufacturing method of the second example, and FIG. 24A is a plan view. 24B is an image in a side view.
  • laser light L having a wavelength of 532 nm is made incident on the inside of the GaN ingot 20 from the surface 20a of the GaN ingot 20, and the first step and the first step of the laser processing method and the semiconductor member manufacturing method of the first example. Similar to the two steps, a plurality of modified spots 13 were formed along the virtual surface 15.
  • the distance between the condensing points C adjacent to each other in the Y direction was 8 ⁇ m
  • the pulse pitch of the laser light L was 10 ⁇ m
  • the pulse energy of the laser light L was 0.3 ⁇ J.
  • the distance between the condensing points C adjacent to each other in the Y direction was 8 ⁇ m
  • the pulse pitch of the laser light L was 10 ⁇ m
  • the pulse energy of the laser light L was 0.3 ⁇ J.
  • the distance between the condensing points C adjacent to each other in the Y direction was 8 ⁇ m
  • the pulse pitch of the laser light L was 5 ⁇ m
  • the pulse energy of the laser light L was 0.3 ⁇ J.
  • the distance between the condensing points C adjacent to each other in the Y direction was 8 ⁇ m
  • the pulse pitch of the laser light L was 5 ⁇ m
  • the pulse energy of the laser light L was 0.3 ⁇ J.
  • the extension amount of the crack 14 extending from the modified spot 13 to the incident side of the laser light L and the opposite side thereof was about 50 ⁇ m.
  • FIG. 24C and 24D are images of modified spots and cracks formed by the laser processing method and the semiconductor member manufacturing method of the third embodiment, and FIG. 24C is a plan view.
  • An image, (d) of FIG. 24, is an image in a side view.
  • a plurality of modified spots 13 are further formed along the virtual surface 15 in the state shown in FIG. 23 (that is, the virtual surface 15 on which a plurality of rows of modified spots 13 have already been formed). .. Specifically, first, first, the distance between adjacent condensing points C in the Y direction is 8 ⁇ m, the pulse pitch of the laser light L is 5 ⁇ m, and the pulse energy of the laser light L is 0.1 ⁇ J.
  • a plurality of rows of reforming spots 13 were formed such that each row was positioned at the center between the rows of reforming spots 13.
  • the extension amount of the crack 14 extending from the modified spot 13 to the incident side of the laser beam L and the opposite side thereof was about 60 ⁇ m.
  • the object 11 of the laser processing method and the semiconductor member manufacturing method of the second example is a GaN wafer (semiconductor wafer, semiconductor object) 30 formed of GaN in a disk shape, for example, as shown in FIG.
  • the GaN wafer 30 has a diameter of 2 inches and the GaN wafer 30 has a thickness of 100 ⁇ m.
  • the laser processing method and the semiconductor member manufacturing method of the second example are performed to cut out a plurality of semiconductor devices (semiconductor members) 40 from the GaN wafer 30.
  • the outer shape of the GaN substrate portion of the semiconductor device 40 is 1 mm ⁇ 1 mm, and the thickness of the GaN substrate portion of the semiconductor device 40 is several tens ⁇ m.
  • the laser processing apparatus 1 described above forms a plurality of modified spots 13 along each of a plurality of virtual surfaces 15.
  • Each of the plurality of virtual surfaces 15 is a surface facing the surface 30a of the GaN wafer 30 inside the GaN wafer 30, and is set so as to be aligned in the direction in which the surface 30a extends.
  • each of the plurality of virtual surfaces 15 is a surface parallel to the surface 30a and has, for example, a rectangular shape.
  • Each of the plurality of virtual planes 15 is set to be arranged two-dimensionally in a direction parallel to the orientation flat 31 of the GaN wafer 30 and a direction perpendicular to the orientation flat 31.
  • a plurality of peripheral regions 16 are set so as to surround each of the plurality of virtual surfaces 15. That is, each of the plurality of virtual surfaces 15 does not reach the side surface 30b of the GaN wafer 30.
  • the width of the peripheral region 16 corresponding to each of the plurality of virtual surfaces 15 is 30 ⁇ m or more.
  • the formation of the plurality of modified spots 13 along each of the plurality of virtual surfaces 15 is performed in the same manner as steps S1 to S4 of the laser processing method and the semiconductor member manufacturing method of the first example.
  • a plurality of modified spots 13 that is, modified spots 13a, 13b, 13c, 13d
  • a plurality of modified spots 13 are provided along each of the plurality of virtual planes 15.
  • 14 that is, the cracks 14a, 14b, 14c, 14d
  • the range in which the plurality of modified spots 13 and the plurality of cracks 14 are formed is indicated by a broken line.
  • the semiconductor manufacturing apparatus forms a plurality of functional elements 32 on the surface 30a of the GaN wafer 30, as shown in FIG.
  • Each of the plurality of functional elements 32 is formed such that one functional element 32 is included in one virtual surface 15 when viewed from the thickness direction of the GaN wafer 30.
  • the functional element 32 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.
  • the semiconductor manufacturing apparatus functions as a heating device when forming the plurality of functional elements 32 on the surface 30a. That is, when forming the plurality of functional elements 32 on the surface 30 a, the semiconductor manufacturing apparatus heats the GaN wafer 30, and the plurality of cracks 14 extending from the plurality of modified spots 13 on each of the plurality of virtual surfaces 15 are formed. Are connected to each other, a crack 17 (that is, a crack 17 across the virtual surface 15) is formed in each of the plurality of virtual surfaces 15. In FIG. 27, the range in which the plurality of modified spots 13, the plurality of cracks 14, and the crack 17 are formed is indicated by broken lines. A heating device different from the semiconductor manufacturing device may be used.
  • the cracks 17 may be formed by connecting the plurality of cracks 14 to each other by applying some force to the GaN wafer 30 by a method other than heating. Further, by forming the plurality of modified spots 13 along the virtual surface 15, the plurality of cracks 14 may be connected to each other to form the crack 17.
  • the crack 17 can be formed by utilizing the pressure of the nitrogen gas.
  • the peripheral region 16 prevents the plurality of cracks 14 from propagating to the outside of the virtual surface 15 surrounded by the peripheral region 16 (for example, the adjacent virtual surface 15 and the side surface 30b of the GaN wafer 30), the plurality of cracks is prevented. It is possible to prevent the nitrogen gas generated in 14 from escaping to the outside of the virtual surface 15.
  • the peripheral area 16 is a non-modified area that does not include the modified spot 13, and when the crack 17 is formed on the virtual surface 15 surrounded by the peripheral area 16, the virtual surface 15 surrounded by the peripheral area 16 is formed. It is a region that prevents the plurality of cracks 14 from propagating to the outside. Therefore, the width of the peripheral region 16 can be set to 30 ⁇ m or more.
  • the laser processing device cuts the GaN wafer 30 into each functional element 32, and the grinding device grinds the portions corresponding to each of the plurality of virtual planes 15, as shown in FIG. 28.
  • a plurality of semiconductor devices 40 are obtained from the GaN wafer 30 with each of the plurality of cracks 17 as a boundary (step S6). In this way, the GaN wafer 30 is cut along each of the plurality of virtual planes 15. In this step, the GaN wafer 30 may be cut into each functional element 32 by mechanical processing (for example, blade dicing) other than laser processing.
  • the laser processing method of the second example includes up to the step of forming the plurality of modified spots 13 along each of the plurality of virtual surfaces 15. Further, among the above steps, the steps up to the step of obtaining the plurality of semiconductor devices 40 from the GaN wafer 30 with each of the plurality of cracks 17 as the boundary are the semiconductor member manufacturing method of the second example.
  • the laser processing method of the second example As described above, according to the laser processing method of the second example, as in the laser processing method of the first example, it is possible to accurately form the plurality of modified spots 13 along each of the plurality of virtual surfaces 15. As a result, the crack 17 can be accurately formed along each of the plurality of virtual surfaces 15. Therefore, according to the laser processing method of the second example, it is possible to obtain a plurality of suitable semiconductor devices 40 by obtaining a plurality of semiconductor devices 40 from the GaN wafer 30 with each of the plurality of cracks 17 as a boundary. .. It is also possible to reuse the GaN wafer 30 after cutting out the plurality of semiconductor devices 40.
  • the laser processing apparatus 1 that implements the laser processing method of the second example, it is possible to accurately form the crack 17 along each of the virtual surfaces 15, and thus a plurality of suitable semiconductors can be formed.
  • the device 40 can be acquired.
  • the plurality of modified spots 13a are formed so that the plurality of cracks 14a extending from the plurality of modified spots 13a are not connected to each other. Thereby, the plurality of modified spots 13b can be formed more accurately along the virtual surface 15.
  • the condensing point C of the pulsed laser light L is moved along the virtual plane 15 to form a plurality of rows of modified spots 13a and pulsed.
  • the plurality of rows of modified spots 13b are formed.
  • gallium nitride contained in the material of the GaN wafer 30 is decomposed by the irradiation of the laser light L, gallium is deposited in the cracks 14a extending from the modified spots 13a. Then, the laser light L is easily absorbed by the gallium. Therefore, forming the plurality of modified spots 13b so as not to overlap the crack 14a is effective in accurately forming the plurality of modified spots 13b along the virtual surface 15.
  • the crack 17 can be easily formed by utilizing the pressure of the nitrogen gas.
  • the cracks 17 can be accurately formed along each of the virtual surfaces 15 by the steps included in the laser processing method of the second embodiment. Therefore, it is possible to obtain a plurality of suitable semiconductor devices 40.
  • the plurality of virtual surfaces 15 are set to be aligned in the direction in which the surface 30a of the GaN wafer 30 extends. This makes it possible to obtain a plurality of semiconductor devices 40 from one GaN wafer 30.
  • the various numerical values regarding the laser light L are not limited to those described above.
  • the pulse energy of the laser light L is 0.1 ⁇ J to 1 ⁇ J and the pulse of the laser light L is The width can be 200 fs to 1 ns.
  • the semiconductor object processed by the laser processing method and the semiconductor member manufacturing method is not limited to the GaN ingot 20 of the first example and the GaN wafer 30 of the second example.
  • the semiconductor member manufactured by the semiconductor member manufacturing method is not limited to the GaN wafer 30 of the first example and the semiconductor device 40 of the second example.
  • One virtual surface may be set for one semiconductor object.
  • the material of the semiconductor object may be SiC. Even in that case, according to the laser processing method and the semiconductor member manufacturing method, as described below, it is possible to accurately form a crack extending over the virtual surface along the virtual surface.
  • FIG. 29A and 29B are images (images in side view) of the cracks of the SiC wafer formed by the laser processing method and the semiconductor member manufacturing method of the comparative example, and FIG. 29A is an enlarged image within a rectangular frame in FIG.
  • laser light having a wavelength of 532 nm is made incident on the inside of the SiC wafer from the surface of the SiC wafer, and the six converging points arranged in the Y direction are relatively moved on the virtual surface along the X direction. By doing so, a plurality of modified spots were formed along the virtual surface.
  • the distance between the condensing points C adjacent to each other in the Y direction was 2 ⁇ m
  • the pulse pitch of the laser light was 15 ⁇ m
  • the pulse energy of the laser light was 4 ⁇ J.
  • a crack extending in a direction inclined by 4° to 5° with respect to the virtual plane occurred.
  • FIG. 30A and 30B are images (images in side view) of the cracks of the SiC wafer formed by the laser processing method and the semiconductor member manufacturing method of the example, and FIG. 30 is an enlarged image in the rectangular frame in FIG.
  • a laser beam having a wavelength of 532 nm is made to enter the inside of the SiC wafer from the surface of the SiC wafer, and the laser processing method and the semiconductor member manufacturing method according to the first embodiment have the same first and second steps.
  • a plurality of modified spots were formed along the virtual plane.
  • FIG. 31 is an image of the peeled surface of the SiC wafer formed by the laser processing method and the semiconductor member manufacturing method of the example, and FIGS. 32A and 32B show the height of the peeled surface shown in FIG. It is a profile. In this case, the unevenness appearing on the peeled surface of the SiC wafer was suppressed to about 2 ⁇ m.
  • the SiC wafers used in the above-described comparative examples and examples are 4H-SiC wafers having an off angle of 4 ⁇ 0.5°, and the direction in which the focusing point of the laser light is moved is the m-axis direction. Is.
  • the method of forming the plurality of modified spots 13a, 13b, 13c, 13d is not limited to the above.
  • the plurality of modified spots 13a may be formed such that the plurality of cracks 14a extending from the plurality of modified spots 13a are connected to each other.
  • the plurality of modified spots 13b may be formed so as not to overlap the plurality of modified spots 13a. Even if the plurality of reforming spots 13b overlap the plurality of cracks 14a extending from the plurality of reforming spots 13a, if the plurality of reforming spots 13b do not overlap the plurality of reforming spots 13a, the plurality of reforming spots 13b do not overlap. 13a and 13b are accurately formed along the virtual surface 15.
  • the method of forming the plurality of modified spots 13c and 13d is arbitrary, and the plurality of modified spots 13c and 13d may not be formed.
  • FIG. 33 for example, by rotating the GaN ingot 20, a plurality of condensing points arranged in the radial direction are relatively rotated (dashed-dotted arrows), and a plurality of rows of modified spots are formed.
  • the formation of the plurality of modified spots 13 may be sequentially performed for each of the plurality of virtual surfaces 15 from the side opposite to the surface 20a. Further, in the laser processing method and the semiconductor member manufacturing method of the first example, the formation of the plurality of modified spots 13 is performed along the one or more virtual surfaces 15 on the front surface 20a side, and the one or more GaN wafers. After the 30 is cut out, the surface 20a of the GaN ingot 20 may be ground, and again, the plurality of modified spots 13 may be formed along the one or more virtual surfaces 15 on the surface 20a side.
  • the peripheral region 16 may not be formed.
  • the peripheral region 16 is not formed in the laser processing method and the semiconductor member manufacturing method of the first example, after forming the plurality of modified spots 13 along each of the plurality of virtual surfaces 15, for example, the GaN ingot 20 is formed. It is also possible to obtain a plurality of GaN wafers 30 by performing etching on them.
  • the laser processing device 1 is not limited to the one having the above-mentioned configuration.
  • the laser processing device 1 may not include the spatial light modulator 4. [Laser Processing Method According to Embodiment and Semiconductor Device Manufacturing Method]
  • FIG. 35 is a diagram showing a laser processing device.
  • the laser processing apparatus 1A is different from the laser processing apparatus 1 shown in FIG. 1 in that the laser processing apparatus 1A further includes a measuring unit 50 and that the laser processing apparatus 1A includes a stage 2A instead of the stage 2.
  • the laser processing apparatus 1 is different.
  • the light source 3, the spatial light modulator 4, and the condenser lens 5 form an irradiation unit 45.
  • the laser processing apparatus 1A includes the stage 2A that supports the GaN wafer 30, the irradiation unit 45 that irradiates the GaN wafer 30 supported by the stage 2A with the laser light L, and the measurement unit that measures the transmittance of the GaN wafer 30. 50 and a control unit 6 that controls the irradiation unit 45 and the measurement unit 50.
  • the stage 2A includes a transmission part 2T that transmits the measurement light IL used for measurement.
  • the measurement unit 50 includes a light source 51 that irradiates the GaN wafer 30 supported by the stage 2A with the measurement light IL, and a photodetector 52 that detects the measurement light IL transmitted through the GaN wafer 30 and the transmission unit 2T. Then, the transmittance of the GaN wafer 30 is measured based on the detection result of the photodetector 52.
  • steps S1 to S3 are carried out in the same manner as the above-mentioned first example. That is, as shown in FIG. 36, by irradiating the laser light L from the surface 30 a of the GaN wafer 30 (in place of the GaN ingot 20) to the inside of the GaN wafer 30, the surface 30 a is opposed to the inside of the GaN wafer 30.
  • a plurality of reforming spots 13 (reforming spots 13a to 13c) and a plurality of deposition regions R containing gallium deposited in the plurality of reforming spots 13 are formed along the virtual surface 15 ( First step). In the first step, of course, the energy of the laser light L on the virtual surface 15 exceeds the processing threshold of the GaN wafer 30.
  • the irradiation conditions of the laser light L when forming the modified spots 13a to 13c can be specified as follows, for example. First, as the pulse energy of the laser light L increases, the deposition region R formed around the modified spot 13 tends to increase. Therefore, when the distance between the condensing points C of the laser light L (for example, in the Y direction) is relatively increased (the modified spot 13 and the deposition region R are relatively coarsely formed), the subsequent laser is used.
  • the pulse energy of the laser light L can be increased from the viewpoint of enlarging the deposition region R by irradiation with light.
  • the laser light is used. Even if the pulse energy of is reduced, the deposition region R can be enlarged by irradiation with laser light in a later step.
  • the pulse pitch of the laser light L is fixed to 10 ⁇ m
  • the pulse energy of the laser light L is set to about 2 ⁇ J.
  • the deposition region R can be enlarged by irradiation with laser light in a later step.
  • the pulse energy of the laser light L is set to about 0.67 ⁇ J, so that the deposition area is formed by the irradiation of the laser light in the subsequent step.
  • R can be expanded.
  • the pulse energy of the laser light L is set to about 0.33 ⁇ J, so that the deposition region is formed by the irradiation of the laser light in a later step. R can be expanded.
  • the transmittance of the GaN wafer 30 is measured (fourth step). Then, it is determined whether the transmittance measured in the fourth step is higher than the reference value (fifth step).
  • the reference value of the transmittance of the GaN wafer 30 can be set to 0.5 (50%), for example. Then, as a result of the determination in the fifth step, if the transmittance is higher than the reference value, the formation of the modified spots 13 is considered to be insufficient, and the first step is performed again. On the other hand, as a result of the determination in the fifth step, if the transmittance is equal to or less than the reference value, the process proceeds to the subsequent step.
  • the GaN wafer 30 is placed in the chamber H of the semiconductor manufacturing apparatus. Then, a semiconductor layer (epitaxial growth layer) 70 for a semiconductor device is formed on the GaN wafer 30 by epitaxial growth.
  • the semiconductor layer 70 is formed on the surface 30 a of the GaN wafer 30.
  • the GaN wafer 30 can be heated to, for example, about 1030° C.
  • the GaN wafer 30 provided with the semiconductor layer 70 is taken out from the chamber H.
  • the condensing point C of the laser light L is arranged so as not to overlap the modified spot 13 when viewed from the direction (Z direction) crossing the surface 30 a of the GaN wafer 30. ..
  • each of the plurality of condensing points C is arranged between the modified spot 13a and the modified spot 13b which are adjacent to each other in the Y direction.
  • the condensing point C may be arranged so as not to overlap the crack 14 and the deposition region R in addition to the modified spot 13.
  • the energy on the virtual surface 15 is set to be lower than the processing threshold of the GaN wafer 30.
  • the laser light L is irradiated to the inside of the GaN wafer 30 from the back surface (the surface of the GaN wafer 30 different from the surface on which the semiconductor layer 70 is formed) 30r opposite to the front surface 30a.
  • This process is based on the following findings. That is, first, by irradiating a semiconductor object containing gallium with laser light, along a virtual plane, a plurality of modified spots, and a deposition region containing gallium deposited in the plurality of modified spots, To form. Then, when the laser light is irradiated again in a later step, the energy of the laser light on the virtual plane is changed (while preventing the modified spots formed in advance from overlapping the focused spots of the laser light). Even if it is lowered below the processing threshold value, the deposition region containing gallium formed in advance can be expanded. As a result, when a semiconductor member is cut out by forming a crack across a virtual surface, it is possible to reduce the unevenness of the cut surface.
  • the laser processing apparatus 1 moves the focal point C of the pulsed laser light L along the virtual surface 15. Further, the pulsed laser light L is modulated by the spatial light modulator 4 so as to be condensed at a plurality of (for example, six) condensing points C arranged in the Y direction. Then, the plurality of condensing points C are relatively moved on the virtual surface 15 along the X direction.
  • the distance between the condensing points C adjacent to each other in the Y direction is 1 ⁇ m
  • the pulse pitch of the laser light L is 10 ⁇ m.
  • the pulse energy of the laser light L is 0.33 ⁇ J.
  • the deposition region R is enlarged.
  • the subsequent steps are the same as those in the above first example. As a result, a semiconductor device including the semiconductor layer 70 is obtained from the GaN wafer 30.
  • the modified spots 13 are formed inside the GaN wafer 30 by the irradiation of the laser light L before the formation of the semiconductor layer 70 for the semiconductor device by the epitaxial growth. .. Therefore, the semiconductor layer 70 cannot be damaged when the modified spot 13 is formed. Therefore, by advancing the crack extending from the modified spot 13 and peeling the GaN wafer 30, a suitable semiconductor device in which damage is suppressed can be obtained.
  • the semiconductor layer 70 in the GaN wafer 30 is formed after the second step so that the condensing point C does not overlap the modified spot 13 when viewed from the direction intersecting the surface 30a.
  • a third step of forming a crack across the virtual surface 15 by irradiating the inside of the GaN wafer 30 with the laser light L from the back surface 30r different from the surface is provided.
  • the irradiation of the laser beam L may form a crack along the virtual surface 15 that is the starting point of peeling.
  • the semiconductor layer 70 is compared with the case where all the laser processing is performed after the formation of the semiconductor layer 70. Damage is suppressed.
  • the laser light L is irradiated from the surface 30a to the inside of the GaN wafer, so that the plurality of modified spots 13 and the plurality of modified spots 13 are formed.
  • the plurality of modified spots 13 are formed along the virtual surface 15 facing the surface 30a that is the incident surface of the laser light L. , And a plurality of deposition regions R containing the deposited gallium.
  • the laser light L is introduced inside the GaN wafer 30 so that the converging point C does not overlap the modified spot 13 and the energy on the virtual surface 15 falls below the processing threshold of the GaN wafer 30. Is irradiated to expand the precipitation region R and form a crack across the virtual surface 15.
  • the above embodiments describe one example of the laser processing method and the semiconductor device manufacturing method according to the present disclosure. Therefore, the laser processing method and the semiconductor device manufacturing method according to the present disclosure are not limited to the above embodiment, and various modifications can be applied.
  • the second step by heating the GaN wafer 30 for epitaxial growth, a plurality of cracks respectively extending from the plurality of modified spots 13 are propagated to form a crack across the virtual surface 15. You may. In this case, the formation of the semiconductor layer 70 and the formation of the crack over the virtual surface 15 can be performed at the same time.
  • the GaN wafer 30 may be provided with the peripheral region 16 that prevents the development of the plurality of cracks 14 extending from the plurality of modified spots 13, respectively.
  • the GaN wafer 30 may be provided with the peripheral region 16 that prevents the development of the plurality of cracks 14 extending from the plurality of modified spots 13, respectively.
  • the transmittance of the GaN wafer 30 is measured in the fourth step, and if the transmittance is determined to be higher than the reference value in the fifth step, the first step is performed again.
  • the case in which the modified spots 13 are sufficiently formed by the above-described example has been described. In this case, damage to the semiconductor layer 70 could be suppressed by lowering the energy of laser processing after forming the semiconductor layer 70 or by refraining from irradiation with laser light.
  • the semiconductor layer 70 is formed in the second step while maintaining the transmittance higher than the reference value, and then in the third step, with the energy exceeding the processing threshold of the GaN wafer 30.
  • Laser processing may be performed.
  • the amount of the modified spots 13 formed in advance is small, it is possible to suppress the warp of the semiconductor layer 70 during the epitaxial growth in the second step. Even in this case, damage to the semiconductor layer 70 is suppressed as compared with the case where all laser processing is performed after the formation of the semiconductor layer 70.
  • the measurement and determination of the transmittance of the GaN wafer 30 are not essential.
  • the above embodiments describe one example of the laser processing method and the semiconductor device manufacturing method according to the present disclosure. Therefore, the laser processing method and the semiconductor device manufacturing method according to the present disclosure are not limited to the above embodiment, and various modifications can be applied.
  • the elements of the first example, the second example, and the respective modified examples can be arbitrarily applied to the method according to the above embodiment.
  • the plurality of modified spots 13 can be formed so that the plurality of cracks 14 extending from the plurality of modified spots 13 are not connected to each other.
  • the condensing point C of the pulsed laser light L is moved along the virtual surface 15 to form a plurality of modified spots 13 as a plurality of modified spots 13.
  • the condensing point C of the pulsed laser light L can be moved along the virtual surface 15 between the rows of the reforming spots 13 in a plurality of rows.
  • a laser processing method capable of obtaining a suitable semiconductor device and a semiconductor device manufacturing method.
  • Reference numeral 13 is a modified spot
  • 15 is a virtual surface
  • 30 is a GaN wafer (semiconductor wafer)
  • 30a is a surface
  • 70 is a semiconductor layer
  • L is a laser beam
  • R is a deposition region.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Plasma & Fusion (AREA)
  • General Chemical & Material Sciences (AREA)
  • Computer Hardware Design (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Chemical & Material Sciences (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Laser Beam Processing (AREA)
  • Processing Of Stones Or Stones Resemblance Materials (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Dicing (AREA)

Abstract

La présente invention concerne un procédé d'usinage au laser destiné à découper une tranche de semi-conducteurs le long d'un plan virtuel qui est à l'intérieur de la tranche de semi-conducteurs et fait face à la surface de la tranche de semi-conducteurs, ledit procédé comprenant : une première étape consistant à former une pluralité de points modifiés le long du plan virtuel à l'intérieur de la tranche de semi-conducteurs par rayonnement de lumière laser dans la tranche de semi-conducteurs à partir de la surface de celle-ci ; et une seconde étape consistant à former, par croissance épitaxiale, sur la tranche de semi-conducteurs après la première étape, une couche de semi-conducteurs pour un dispositif à semi-conducteurs.
PCT/JP2019/049955 2018-12-21 2019-12-19 Procédé d'usinage au laser et procédé de fabrication de dispositif à semi-conducteurs WO2020130108A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2018239492A JP7330695B2 (ja) 2018-12-21 2018-12-21 レーザ加工方法、及び、半導体デバイス製造方法
JP2018-239492 2018-12-21

Publications (1)

Publication Number Publication Date
WO2020130108A1 true WO2020130108A1 (fr) 2020-06-25

Family

ID=71101283

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2019/049955 WO2020130108A1 (fr) 2018-12-21 2019-12-19 Procédé d'usinage au laser et procédé de fabrication de dispositif à semi-conducteurs

Country Status (3)

Country Link
JP (1) JP7330695B2 (fr)
TW (1) TW202108275A (fr)
WO (1) WO2020130108A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113369677B (zh) * 2021-05-31 2022-05-31 深圳赛意法微电子有限公司 晶圆切割方法及切割设备

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003535472A (ja) * 2000-05-30 2003-11-25 コミツサリア タ レネルジー アトミーク 脆弱化された基板およびそのような基板の製造方法
WO2010082267A1 (fr) * 2009-01-15 2010-07-22 並木精密宝石株式会社 Substrat de reformage intérieur pour croissance épitaxiale, élément de formation de couche de cristal, dispositif et substrat massif produit à l'aide de ce dernier, et son procédé de production
WO2011108698A1 (fr) * 2010-03-05 2011-09-09 並木精密宝石株式会社 Substrat à reformage interne pour croissance épitaxiale, substrat à reformage interne avec film multicouche, dispositif à semi-conducteur, substrat semi-conducteur massif et leurs procédés de production
JP2012169363A (ja) * 2011-02-10 2012-09-06 Saitama Univ 基板加工方法
WO2017163548A1 (fr) * 2016-03-24 2017-09-28 日本碍子株式会社 Procédé de production d'un substrat de cristal germe, procédé de production d'un cristal de nitrure d'élément du groupe 13, et substrat de cristal germe
JP2017183600A (ja) * 2016-03-31 2017-10-05 パナソニックＩｐマネジメント株式会社 スライス方法およびスライス装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003535472A (ja) * 2000-05-30 2003-11-25 コミツサリア タ レネルジー アトミーク 脆弱化された基板およびそのような基板の製造方法
WO2010082267A1 (fr) * 2009-01-15 2010-07-22 並木精密宝石株式会社 Substrat de reformage intérieur pour croissance épitaxiale, élément de formation de couche de cristal, dispositif et substrat massif produit à l'aide de ce dernier, et son procédé de production
WO2011108698A1 (fr) * 2010-03-05 2011-09-09 並木精密宝石株式会社 Substrat à reformage interne pour croissance épitaxiale, substrat à reformage interne avec film multicouche, dispositif à semi-conducteur, substrat semi-conducteur massif et leurs procédés de production
JP2012169363A (ja) * 2011-02-10 2012-09-06 Saitama Univ 基板加工方法
WO2017163548A1 (fr) * 2016-03-24 2017-09-28 日本碍子株式会社 Procédé de production d'un substrat de cristal germe, procédé de production d'un cristal de nitrure d'élément du groupe 13, et substrat de cristal germe
JP2017183600A (ja) * 2016-03-31 2017-10-05 パナソニックＩｐマネジメント株式会社 スライス方法およびスライス装置

Also Published As

Publication number Publication date
JP7330695B2 (ja) 2023-08-22
TW202108275A (zh) 2021-03-01
JP2020102521A (ja) 2020-07-02

Similar Documents

Publication Publication Date Title
WO2020130109A1 (fr) Procédé d'usinage par laser et procédé de production d'élément semi-conducteur
KR102128416B1 (ko) 레이저 가공 장치 및 레이저 가공 방법
KR20150135262A (ko) 레이저 가공 장치 및 레이저 가공 방법
JP2013157452A (ja) 半導体デバイスの製造方法
JP2016015463A (ja) ＳｉＣ材料の加工方法及びＳｉＣ材料
JP6012185B2 (ja) 半導体デバイスの製造方法
JP7123759B2 (ja) レーザスライス装置、及びレーザスライス方法
WO2020130108A1 (fr) Procédé d'usinage au laser et procédé de fabrication de dispositif à semi-conducteurs
JP5361916B2 (ja) レーザスクライブ方法
WO2020130054A1 (fr) Procédé de traitement laser, procédé de fabrication d'élément semi-conducteur et dispositif de traitement laser
WO2020130110A1 (fr) Appareil d'usinage au laser
WO2020129569A1 (fr) Procédé d'usinage au laser, procédé de production d'élément semi-conducteur, et objet semi-conducteur
JP6542630B2 (ja) レーザ加工方法及びレーザ加工装置
JP7246919B2 (ja) レーザ加工方法、半導体部材製造方法及びレーザ加工装置
WO2021153353A1 (fr) Procédé d'usinage par laser, procédé de fabrication d'élément semi-conducteur et dispositif d'usinage par laser
WO2021153354A1 (fr) Procédé d'usinage par laser, procédé de fabrication d'élément semi-conducteur et dispositif d'usinage par laser
US20230123795A1 (en) Singulation of optical devices from optical device substrates via laser ablation
JP2023183070A (ja) レーザ加工方法、半導体デバイスの製造方法、及びレーザ加工装置
KR20230123917A (ko) 레이저 가공 장치 및 레이저 가공 방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19898446

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19898446

Country of ref document: EP

Kind code of ref document: A1