WO2014030518A1 - 加工対象物切断方法 - Google Patents
加工対象物切断方法 Download PDFInfo
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- WO2014030518A1 WO2014030518A1 PCT/JP2013/070905 JP2013070905W WO2014030518A1 WO 2014030518 A1 WO2014030518 A1 WO 2014030518A1 JP 2013070905 W JP2013070905 W JP 2013070905W WO 2014030518 A1 WO2014030518 A1 WO 2014030518A1
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- sapphire substrate
- single crystal
- crystal sapphire
- back surface
- along
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
- H01L24/98—Methods for disconnecting semiconductor or solid-state bodies
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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
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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
- B23K26/0006—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
- B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
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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
- B23K26/36—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
- B23K26/36—Removing material
- B23K26/40—Removing material taking account of the properties of the material involved
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- 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
- B28D5/0005—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by breaking, e.g. dicing
- B28D5/0011—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by breaking, e.g. dicing with preliminary treatment, e.g. weakening by scoring
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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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
- H01L21/70—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
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/76—Making of isolation regions between components
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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
- H01L21/70—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
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
- H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
- H01L21/76886—Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances
- H01L21/76892—Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances modifying the pattern
- H01L21/76894—Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances modifying the pattern using a laser, e.g. laser cutting, laser direct writing, laser repair
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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
- H01L21/70—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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
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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
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T225/00—Severing by tearing or breaking
- Y10T225/10—Methods
- Y10T225/12—With preliminary weakening
Definitions
- the present invention relates to a processing object cutting method for manufacturing a plurality of light emitting elements by cutting a processing object including a single crystal sapphire substrate for each light emitting element portion.
- Patent Document 1 discloses that separation grooves are formed on the front and back surfaces of a sapphire substrate by dicing or scribing, and a work-affected portion is formed in the sapphire substrate by irradiation with laser light. A method is described in which the sapphire substrate is cut along a separation groove and a work-affected portion, formed in multiple stages.
- the present invention provides a process capable of suppressing variations in the meandering amount of cracks generated from a modified region formed along each of a plurality of scheduled cutting lines parallel to the a-plane and the back surface of a single crystal sapphire substrate.
- An object is to provide a method for cutting an object.
- the present inventors have generated from a modified region formed along each of a plurality of scheduled cutting lines parallel to the a surface and the back surface of the single crystal sapphire substrate.
- the variation in the meandering amount of the crack is caused by the relationship between the direction in which the laser light condensing point is relatively moved along the planned cutting line and the direction in which the r-plane of the single crystal sapphire substrate is inclined. I figured out what I was doing.
- the method for cutting a workpiece includes a single crystal sapphire substrate having a front surface and a back surface that form an angle corresponding to the c-plane and a plurality of light emitting element portions arranged in a matrix on the front surface.
- a processing object cutting method for manufacturing a plurality of light emitting elements by cutting a processing object provided with an element layer for each light emitting element section, and a back surface of the single crystal sapphire substrate on which the laser light is incident
- a plurality of first values set so as to be parallel to the a-plane and the back surface of the single crystal sapphire substrate by aligning the condensing point of the laser light with the position in the single crystal sapphire substrate that is separated from the back surface by the first distance.
- the first modified region is formed in the single crystal sapphire substrate along each of the first scheduled cutting lines by relatively moving the focusing point from one side to the other side along each of the planned cutting lines.
- laser light is condensed from one side to the other side in each of a plurality of first cutting scheduled lines set to be parallel to the a-plane and the back surface of the single crystal sapphire substrate. Move the points relatively. Thereby, it can suppress that the amount of meandering of the 1st crack which occurred from the 1st modification field formed along each of the 1st scheduled cutting line changes. Therefore, according to this workpiece cutting method, variation in the meandering amount of cracks generated from the modified regions formed along each of a plurality of scheduled cutting lines parallel to the a-plane and the back surface of the single-crystal sapphire substrate is reduced. It becomes possible to suppress.
- the off angle includes the case of 0 °. In this case, the front and back surfaces of the single crystal sapphire substrate are parallel to the c-plane.
- the side where the angle between the r-plane and the back surface of the single crystal sapphire substrate is an acute angle is one side
- the side where the angle between the r-plane and the back surface is an obtuse angle is the other side.
- the condensing point of the laser beam is relatively moved from the side where the angle between the r-plane and the back surface of the single crystal sapphire substrate is an obtuse angle to the side where the angle is an acute angle.
- the amount of meandering of the first crack that reaches the back surface of the single crystal sapphire substrate from the one modified region can be suppressed to be small.
- an external force is applied to the workpiece along each of the first scheduled cutting lines by pressing the knife edge against the workpiece from the surface side along each of the first scheduled cutting lines. You may let them. According to this, since an external force acts on the workpiece so that the first crack reaching the back surface of the single crystal sapphire substrate is opened, the workpiece is easily and accurately along the first scheduled cutting line. Can be cut off.
- the workpiece cutting method is such that, before the second step, the back surface is the incident surface, the focusing point is aligned within the single crystal sapphire substrate, and is parallel to the m-plane and the back surface of the single crystal sapphire substrate.
- a second modified region is formed in the single crystal sapphire substrate along each of the second scheduled cutting lines by relatively moving the condensing point along each of the set second scheduled cutting lines.
- an external force is applied to the workpiece along each of the second scheduled cutting lines, thereby extending the second crack generated from the second modified region.
- a fourth step of cutting the workpiece along each of the second scheduled cutting lines is such that, before the second step, the back surface is the incident surface, the focusing point is aligned within the single crystal sapphire substrate, and is parallel to the m-plane and the back surface of the single crystal sapphire substrate.
- the workpiece can be cut easily and accurately along the first scheduled cutting line and the second scheduled cutting line.
- the third step may be performed before the first step or may be performed after the first step as long as it is before the second step.
- the fourth step may be performed before the fourth step or after the fourth step as long as it is after the first step and the third step.
- a focusing point is aligned with a position in the single crystal sapphire substrate that is separated from the back surface by a second distance larger than the first distance, and each of the first scheduled cutting lines
- a third modified region is formed in the single crystal sapphire substrate along each of the first scheduled cutting lines by relatively moving the focusing point from the other side to the one side along the second step. Then, by applying an external force to the object to be processed along each of the first cutting scheduled lines, the first crack and the third crack generated from the third modified region are extended, and the first cutting scheduled line You may cut
- the workpiece can be easily and accurately cut along the first scheduled cutting line. Further, by moving the condensing point of the laser beam in the opposite direction when forming the first modified region and when forming the third modified region, for example, for each first cutting scheduled line, When the modified region is formed and then the first modified region is formed continuously, the condensing point of the laser beam can be moved efficiently.
- a focusing point is aligned with a position in the single crystal sapphire substrate that is separated from the back surface by a second distance larger than the first distance, and each of the first scheduled cutting lines
- a third modified region is formed in the single crystal sapphire substrate along each of the first scheduled cutting lines by relatively moving the focusing point from one side to the other side along the second step. Then, by applying an external force to the object to be processed along each of the first cutting scheduled lines, the first crack and the third crack generated from the third modified region are extended, and the first cutting scheduled line You may cut
- the workpiece can be easily and accurately cut along the first scheduled cutting line. Further, by moving the laser light condensing point in the same direction during the formation of the first modified region and during the formation of the third modified region, the first crack is simply removed during the formation of the first modified region. It is possible to reliably reach the back surface of the crystal sapphire substrate.
- FIG. 3 is a cross-sectional view taken along the line III-III of the workpiece in FIG. 2. It is a top view of the processing target after laser processing.
- FIG. 5 is a cross-sectional view taken along the line VV of the workpiece in FIG. 4.
- FIG. 5 is a cross-sectional view taken along line VI-VI of the workpiece in FIG. 4. It is a top view of the processing object used as the object of the processing object cutting method of a 1st embodiment of the present invention.
- the modified region is formed inside the processing object along the planned cutting line by irradiating the processing object with laser light along the planned cutting line.
- a laser processing apparatus 100 includes a laser light source 101 that oscillates a laser beam L, a dichroic mirror 103 that is arranged so as to change the direction of the optical axis (optical path) of the laser beam L, and A condensing lens 105 for condensing the laser light L. Further, the laser processing apparatus 100 includes a support base 107 for supporting the workpiece 1 irradiated with the laser light L condensed by the condensing lens 105, and a stage 111 for moving the support base 107. And a laser light source control unit 102 for controlling the laser light source 101 to adjust the output of the laser light L, the pulse width, and the like, and a stage control unit 115 for controlling the movement of the stage 111.
- the laser light L emitted from the laser light source 101 has its optical axis changed by 90 ° by the dichroic mirror 103, and the inside of the processing object 1 placed on the support base 107.
- the light is condensed by the condensing lens 105.
- the stage 111 is moved, and the workpiece 1 is moved relative to the laser beam L along the planned cutting line 5. As a result, a modified region along the planned cutting line 5 is formed on the workpiece 1.
- a cutting target line 5 for cutting the processing object 1 is set in the processing object 1.
- the planned cutting line 5 is a virtual line extending linearly.
- the laser beam L is projected along the planned cutting line 5 in a state where the focused point P is aligned with the inside of the workpiece 1. It moves relatively (that is, in the direction of arrow A in FIG. 2).
- the modified region 7 is formed inside the workpiece 1 along the planned cutting line 5, and the modified region 7 formed along the planned cutting line 5 is formed. It becomes the cutting start area 8.
- the condensing point P is a location where the laser light L is condensed.
- the planned cutting line 5 is not limited to a straight line, but may be a curved line, or may be a line actually drawn on the surface 3 of the workpiece 1 without being limited to a virtual line.
- the modified region 7 may be formed continuously or intermittently. Further, the modified region 7 may be in the form of a line or a dot. In short, the modified region 7 only needs to be formed at least inside the workpiece 1.
- a crack may be formed starting from the modified region 7, and the crack and modified region 7 may be exposed on the outer surface (front surface, back surface, or outer peripheral surface) of the workpiece 1.
- the laser light L here passes through the workpiece 1 and is particularly absorbed near the condensing point inside the workpiece 1, thereby forming the modified region 7 in the workpiece 1. (Ie, internal absorption laser processing). Therefore, since the laser beam L is hardly absorbed by the surface 3 of the workpiece 1, the surface 3 of the workpiece 1 is not melted. In general, when a removed portion such as a hole or a groove is formed by being melted and removed from the front surface 3 (surface absorption laser processing), the processing region gradually proceeds from the front surface 3 side to the back surface side.
- the modified region formed in the present embodiment refers to a region in which density, refractive index, mechanical strength, and other physical characteristics are different from the surroundings.
- the modified region include a melt treatment region, a crack region, a dielectric breakdown region, a refractive index change region, and the like, and there is a region where these are mixed.
- the modified region there are a region in which the density of the modified region in the material to be processed is changed as compared with the density of the non-modified region, and a region in which lattice defects are formed (collectively these are high-density regions). Also known as the metastatic region).
- the area where the density of the melt treatment area, the refractive index change area, the modified area has changed compared to the density of the non-modified area, and the area where lattice defects are formed are further included in these areas and the modified areas.
- cracks are included in the interface between the non-modified region and the non-modified region.
- the included crack may be formed over the entire surface of the modified region, or may be formed in only a part or a plurality of parts.
- the modified region 7 is formed by forming a plurality of modified spots (processing marks) along the planned cutting line 5.
- the modified spot is a modified portion formed by one pulse shot of pulsed laser light (that is, one pulse of laser irradiation: laser shot).
- Examples of the modified spot include a crack spot, a melting treatment spot, a refractive index change spot, or a mixture of at least one of these.
- the workpiece 1 is a wafer including a single crystal sapphire substrate 31 having a circular plate shape (for example, 2 to 6 inches in diameter and 50 to 200 ⁇ m in thickness).
- the single crystal sapphire substrate 31 has a hexagonal crystal structure, and the c-axis is an angle ⁇ (for example, 0.1 mm with respect to the thickness direction of the single crystal sapphire substrate 31). °) Inclined. That is, the single crystal sapphire substrate 31 has an off angle of the angle ⁇ .
- ⁇ for example, 0.1 mm with respect to the thickness direction of the single crystal sapphire substrate 31.
- the single crystal sapphire substrate 31 has a front surface 31a and a back surface 31b that form an angle ⁇ corresponding to the c-plane and an off angle.
- the m plane is inclined at an angle ⁇ with respect to the thickness direction of the single crystal sapphire substrate 31 (see FIG. 9A), and the a plane is the thickness of the single crystal sapphire substrate 31. It is parallel to the vertical direction (see FIG. 9B).
- the workpiece 1 includes an element layer 33 including a plurality of light emitting element portions 32 arranged in a matrix on the surface 31 a of the single crystal sapphire substrate 31.
- a cutting planned line (first cutting planned line) 51 and a cutting planned line (second cutting planned line) 52 for cutting the processing target 1 for each light emitting element part 32 are in a grid pattern (for example, 300 ⁇ m ⁇ 300 ⁇ m).
- a plurality of scheduled cutting lines 51 are set to be parallel to the a-plane and the back surface 31b (in other words, to be parallel to the a-plane and the front surface 31a).
- a plurality of scheduled cutting lines 52 are set to be parallel to the m-plane and the back surface 31b (in other words, to be parallel to the m-plane and the front surface 31a).
- an orientation flat 31c is formed on the single crystal sapphire substrate 31 so as to be parallel to the a-plane.
- each light emitting element portion 32 is stacked on the n-type semiconductor layer (first conductivity type semiconductor layer) 34 stacked on the surface 31 a of the single crystal sapphire substrate 31 and on the n-type semiconductor layer 34.
- P-type semiconductor layer (second conductivity type semiconductor layer) 35 P-type semiconductor layer (second conductivity type semiconductor layer) 35.
- the n-type semiconductor layer 34 is continuously formed over all the light-emitting element portions 32, and the p-type semiconductor layer 35 is separated for each light-emitting element portion 32 and formed in an island shape.
- the n-type semiconductor layer 34 and the p-type semiconductor layer 35 are made of a III-V group compound semiconductor such as GaN, for example, and are pn-junctioned with each other. As shown in FIG.
- an electrode pad 36 is formed for each light emitting element portion 32 in the n-type semiconductor layer 34, and an electrode pad 37 is formed for each light emitting element portion 32 in the p-type semiconductor layer 35.
- the n-type semiconductor layer 34 has a thickness of about 6 ⁇ m, for example, and the p-type semiconductor layer 35 has a thickness of about 1 ⁇ m, for example.
- a street region 38 having a predetermined width extends in a lattice shape between the light emitting element portions 32 and 32 adjacent to each other in the element layer 33.
- the street region 38 has a member having an outer edge closest to the other light emitting element portion 32B among the members exclusively occupied by one light emitting element portion 32A and the other light emitting element. This is a region between the member exclusively used by the portion 32B and the member having the outer edge closest to the one light emitting element portion 32A.
- the member having the outer edge closest to the light emitting element portion 32B among the members exclusively used by the light emitting element portion 32A is the p-type semiconductor layer 35, and among the members exclusively occupied by the light emitting element portion 32B.
- Members having the outer edge closest to the light emitting element portion 32 ⁇ / b> A are the electrode pad 36 and the p-type semiconductor layer 35.
- the street region 38 in this case is a region between the p-type semiconductor layer 35 of the light-emitting element portion 32A and the electrode pad 36 and the p-type semiconductor layer 35 of the light-emitting element portion 32B.
- the n-type semiconductor layer 34 shared by the light emitting element portion 32 ⁇ / b> A and the light emitting element portion 32 ⁇ / b> B is exposed in the street region 38.
- the member having the outer edge closest to the light emitting element portion 32B among the members exclusively used by the light emitting element portion 32A is the n-type semiconductor layer 34, and among the members exclusively occupied by the light emitting element portion 32B.
- the member having the outer edge closest to the light emitting element portion 32 ⁇ / b> A is the n-type semiconductor layer 34.
- the street region 38 in this case is a region between the n-type semiconductor layer 34 of the light-emitting element portion 32A and the n-type semiconductor layer 34 of the light-emitting element portion 32B.
- the surface 31 a of the single crystal sapphire substrate 31 is exposed in the street region 38.
- a processing object cutting method for manufacturing a plurality of light emitting elements by cutting the processing object 1 configured as described above for each light emitting element section 32 will be described below.
- a protective tape 41 is attached to the workpiece 1 so as to cover the element layer 33, and the workpiece is placed on the support base 107 of the laser processing apparatus 100 described above via the protective tape 41. 1 is placed.
- the back surface 31b of the single crystal sapphire substrate 31 is used as the incident surface of the laser light L in the single crystal sapphire substrate 31, and the condensing point P of the laser light L is aligned in the single crystal sapphire substrate 31, and each of the planned cutting lines 51
- the condensing point P is relatively moved along.
- a modified region (first modified region) 71 is formed in the single crystal sapphire substrate 31 along each of the planned cutting lines 51, and a crack (first crack) 81 generated from the modified region 71 is formed. Reach the back surface 31b (first step). At this time, the crack 81 does not reach the surface 31a of the single crystal sapphire substrate 31, but extends from the modified region 71 to the surface 31a side.
- the side formed by the acute angle between the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is one side, and the angle formed by the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is an obtuse angle.
- the condensing point P of the laser light L is relatively moved from one side to the other side in all the scheduled cutting lines 51 with the side as the other side.
- the distance (first distance) from the back surface 31b to the position where the condensing point P is aligned is, for example, a distance less than half the thickness of the single crystal sapphire substrate 31, and is, for example, 30 to 50 ⁇ m.
- the back surface 31b of the single crystal sapphire substrate 31 is used as the incident surface of the laser light L on the single crystal sapphire substrate 31, and the condensing point P of the laser light L is aligned in the single crystal sapphire substrate 31.
- the condensing point P is relatively moved along each of the scheduled cutting lines 52.
- a modified region (second modified region) 72 is formed in the single crystal sapphire substrate 31 along each of the planned cutting lines 52, and a crack (second crack) 82 generated from the modified region 72 is formed.
- the crack 82 does not reach the surface 31 a of the single crystal sapphire substrate 31, but also extends from the modified region 72 to the surface 31 a side.
- the distance from the center line CL of the street region 38 extending in the direction parallel to the m-plane between the adjacent light emitting element portions 32, 32 to the position where the condensing point P is aligned is “from the direction perpendicular to the back surface 31b.
- ⁇ Y thickness of single crystal sapphire substrate 31: t
- distance from back surface 31b to position where converging point P is aligned Z
- width of street region 38 d
- the center line CL is a center line in the width direction of the street region 38 (that is, the direction in which the adjacent light emitting element portions 32 and 32 are arranged).
- the meandering amount m of the crack 82 on the surface 31a is an “assumed maximum value” of the swing width of the crack 82 meandering on the surface 31a (the swing width in the width direction of the street region 38), for example, ⁇ 5 to +5 ⁇ m. It is.
- the direction in which the crack 82 extends is the direction in which the r-plane is inclined with respect to the direction perpendicular to the back surface 31b, but the angle formed between the direction perpendicular to the back surface 31b and the direction in which the crack 82 extends.
- ⁇ does not necessarily coincide with the angle between the direction perpendicular to the back surface 31b and the r-plane, and is, for example, 5 to 7 °.
- the operation of the laser processing apparatus 100 in this process is as follows. First, the laser processing apparatus 100 detects a street region 38 extending from the back surface 31b side of the single crystal sapphire substrate 31 in a direction parallel to the m-plane between the adjacent light emitting element portions 32 and 32. Subsequently, the laser processing apparatus 100 applies the laser beam to the processing target 1 so that the position where the condensing point P is aligned is located on the center line CL of the street region 38 when viewed from the direction perpendicular to the back surface 31b. Adjust the irradiation position of L.
- the laser processing apparatus 100 when viewed from the direction perpendicular to the back surface 31b, causes the laser beam L for the workpiece 1 so that the position where the converging point P is aligned is offset from the center line CL by ⁇ Y. Adjust the irradiation position. Subsequently, the laser processing apparatus 100 starts irradiating the processing target 1 with the laser beam L, and when viewed from a direction perpendicular to the back surface 31b, the position where the condensing point P is aligned is the center line CL (here, The condensing point P is relatively moved along each of the planned cutting lines 52 in a state offset by ⁇ Y with respect to the planned cutting line 52).
- the modified regions 71 and 72 formed in the single crystal sapphire substrate 31 include a melt processing region.
- the crack 81 generated from the modified region 71 and the crack 82 generated from the modified region 72 can reach the back surface 31b of the single crystal sapphire substrate 31 by appropriately adjusting the irradiation condition of the laser light L. It is.
- the irradiation conditions of the laser beam L for causing the cracks 81 and 82 to reach the back surface 31b include, for example, the distance from the back surface 31b to the position where the condensing point P of the laser beam L is aligned, the pulse width of the laser beam L, and the laser beam L pulse pitch (a value obtained by dividing “the moving speed of the condensing point P of the laser beam L relative to the workpiece 1” by “the repetition frequency of the laser beam L”), the pulse energy of the laser beam L, and the like.
- the crack 81 is difficult to extend and the crack 81 is likely to meander in the planned cutting line 51 set so as to be parallel to the a-plane and the back surface 12b.
- the crack 82 is easy to extend and the crack 82 is difficult to meander.
- the pulse pitch of the laser light L on the planned cutting line 51 side may be smaller than the pulse pitch of the laser light L on the planned cutting line 52 side.
- the expanded tape 42 is applied to the workpiece 1 so as to cover the back surface 31b of the single crystal sapphire substrate 31, and a three-point bending break is applied.
- the workpiece 1 is placed on the receiving member 43 of the apparatus via the expanded tape 42.
- the knife edge 44 is pressed against the workpiece 1 via the protective tape 41 from the surface 31 a side of the single crystal sapphire substrate 31 along each of the scheduled cutting lines 51.
- an external force is applied to the workpiece 1 along each of the scheduled cutting lines 51.
- the crack 81 generated from the modified region 71 is extended to the surface 31a side, and the workpiece 1 is cut into a bar shape along each of the scheduled cutting lines 51 (second step).
- the knife edge 44 is pushed to the workpiece 1 through the protective tape 41 from the surface 31 a side of the single crystal sapphire substrate 31 along each of the planned cutting lines 52.
- an external force is applied to the workpiece 1 along each of the scheduled cutting lines 52.
- the crack 82 generated from the modified region 72 is extended to the surface 31a side, and the workpiece 1 is cut into a chip shape along each of the scheduled cutting lines 52 (fourth step).
- the protective tape 41 is removed from the workpiece 1 and the expanded tape 42 is expanded outward. Thereby, the some light emitting element 10 obtained by cut
- the crack 82 generated from the modified region 71 formed along each of the plurality of scheduled cutting lines 51 parallel to the a-plane and the back surface 31b of the single crystal sapphire substrate 31 Variations in the meandering amount can be suppressed.
- the meandering amount of the crack 81 generated from the modified region 71 is the swing width of the crack 81 meandering on the front surface 31a or the back surface 31b of the single crystal sapphire substrate 31 (the swing width in the width direction of the street region 38).
- the side where the angle formed between the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is an acute angle is one side, and the side where the angle is an obtuse angle is the other side.
- the focusing point P of the laser beam L is relatively moved from one side to the other side along each of the planned cutting lines 51 to form the modified region 71 in the single crystal sapphire substrate 31,
- the crack 81 generated from the modified region 71 is made to reach the back surface 31b.
- the condensing point P of the laser beam L is relatively moved from the side where the angle between the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is an obtuse angle to the side where the angle is an acute angle. Further, the meandering amount of the crack 81 that reaches the back surface 31b of the single crystal sapphire substrate 31 from the modified region 71 can be suppressed small.
- the cutting scheduled line is formed by pressing the knife edge 44 against the workpiece 1 from the surface 31 a side of the single crystal sapphire substrate 31 along each of the scheduled cutting lines 51 and 52.
- An external force is applied to the workpiece 1 along each of 51 and 52.
- an external force acts on the workpiece 1 so that the cracks 81 and 82 that have reached the back surface 31b of the single crystal sapphire substrate 31 are opened, so that the cutting target lines 51 and 52 can be easily and accurately aligned.
- the workpiece 1 can be cut.
- ⁇ Y (tan ⁇ ) ⁇ (t ⁇ Z) ⁇ [(d / 2) in each of the plurality of scheduled cutting lines 52 set to be parallel to the m-plane and the back surface 31b of the single crystal sapphire substrate 31. ) -M] to irradiate the workpiece 1 with the laser beam L to form the modified region 72 in the single crystal sapphire substrate 31, and the crack 82 generated from the modified region 72 reaches the back surface 31b.
- the crack 82 can be contained in the street region 38 on the surface 31a of the single crystal sapphire substrate 31, It is possible to prevent the crack 81 from reaching the light emitting element portion 32. This is because "the extension direction of the crack 82 generated from the modified region 72 formed along the planned cutting line 52 parallel to the m-plane and the back surface 31b of the single crystal sapphire substrate 31 is greater than the influence of the m-plane. It is based on the knowledge that it is strongly influenced by the r-plane inclined with respect to the surface and is pulled in the direction of inclination of the r-plane.
- the position where the condensing point P is aligned is offset by ⁇ Y with respect to the center line CL of the street region 38, so that the position where the condensing point P is aligned is a single crystal. Even if it is separated from the surface 31 a of the sapphire substrate 31, the crack 82 generated from the modified region 72 can be accommodated in the street region 38, so that the characteristics of the light emitting element portion 32 deteriorate due to the irradiation with the laser light L. Can be prevented.
- t thickness of the single crystal sapphire substrate 31: 150 ⁇ m
- Z distance from the back surface 31b to the position where the converging point P is aligned
- d width of the street region 38
- 20 20 ⁇ m
- m front surface 31a
- Meandering amount of the crack 82 3 ⁇ m
- ⁇ angle formed by the direction perpendicular to the back surface 31b and the direction in which the crack 82 extends
- ⁇ Y (tan ⁇ ) ⁇ (t ⁇ Z ) ⁇ [(d / 2) ⁇ m]
- ⁇ Y 10 ⁇ 7 ⁇ m.
- the cut line 52 is aligned with each of the planned cutting lines 52 in a state where the position where the converging point P is aligned is offset by 3 to 17 ⁇ m with respect to the center line CL of the street region 38.
- the focusing point P may be moved relatively.
- the workpiece cutting method of the second embodiment is different from the workpiece cutting method of the first embodiment described above in the step of forming the modified region 72 and the step of cutting the workpiece 1.
- the processing object cutting method of the second embodiment will be described mainly with respect to the different steps.
- the laser beam L is irradiated to the processing object 1 along each of the planned cutting lines 51, thereby along each of the planned cutting lines 51.
- the modified region 71 is formed in the single crystal sapphire substrate 31, and the crack 81 generated from the modified region 71 is made to reach the back surface 31b of the single crystal sapphire substrate 31 (first step).
- the back surface 31 b of the single crystal sapphire substrate 31 is used as the incident surface of the laser light L on the single crystal sapphire substrate 31, and the condensing point P of the laser light L is aligned in the single crystal sapphire substrate 31.
- the condensing point P is relatively moved along each of the scheduled cutting lines 52.
- the modified region 72 is formed in the single crystal sapphire substrate 31 along each of the planned cutting lines 52, and the crack 82 generated from the modified region 72 reaches the surface 31a of the single crystal sapphire substrate 31 ( (3rd process).
- the crack 82 does not reach the back surface 31b of the single crystal sapphire substrate 31, but extends from the modified region 72 to the back surface 31b side.
- the width of the street region 38 extending in the direction parallel to the m-plane between the light emitting element portions 32 and 32, d, the amount of meandering of the crack 82 on the front surface 31a: m, and the direction perpendicular to the back surface 31b that is, single crystal sapphire Cutting is performed so as to satisfy t ⁇ [(d / 2) ⁇ m] / tan ⁇ ⁇ Z ⁇ te, where ⁇ is an angle formed between the thickness direction of the substrate 31 and the direction in which the crack 82 extends.
- the workpiece 1 is irradiated with the laser beam L along each of the planned lines 52.
- the allowable minimum distance e from the position where the condensing point P is aligned to the surface 31a is reduced by the irradiation of the laser beam L when the distance from the position where the condensing point P is aligned to the surface 31a is smaller than the allowable minimum distance e.
- the distance that may deteriorate the characteristics of the light emitting element section 32 for example, 40 to 60 ⁇ m.
- the crack 82 generated from the modified region 72 can reach the surface 31a of the single crystal sapphire substrate 31 by appropriately adjusting the irradiation condition of the laser light L.
- irradiation conditions of the laser beam L for causing the crack 82 to reach the front surface 31a for example, the distance from the back surface 31b to the position where the condensing point P of the laser beam L is aligned, the pulse width of the laser beam L, the laser beam L There are a pulse pitch, pulse energy of the laser beam L, and the like.
- the expanded tape 42 is attached to the workpiece 1 so as to cover the back surface 31b of the single crystal sapphire substrate 31.
- the workpiece 1 is placed on the receiving member 43 of the point bending break device via the expanded tape 42.
- the knife edge 44 is pressed against the workpiece 1 via the protective tape 41 from the surface 31a side of the single crystal sapphire substrate 31 along each of the planned cutting lines 51, so that each of the planned cutting lines 51 is cut.
- An external force is applied to the workpiece 1 along the line. Thereby, the crack 81 generated from the modified region 71 is extended to the surface 31a side, and the workpiece 1 is cut into a bar shape along each of the scheduled cutting lines 51 (second step).
- the workpiece 1 is reversed, and the workpiece 1 is placed on the receiving member 43 of the three-point bending break device via the protective tape 41. Then, the knife edge 44 is pressed against the workpiece 1 through the expanded tape 42 from the back surface 31b side of the single crystal sapphire substrate 31 along each of the planned cutting lines 52, so that each of the planned cutting lines 52 is cut. An external force is applied to the workpiece 1 along the line. Thereby, the crack 82 generated from the modified region 72 is extended to the back surface 31b side, and the workpiece 1 is cut into a chip shape along each of the scheduled cutting lines 52 (fourth step).
- the protective tape 41 is removed from the workpiece 1 and the expanded tape 42 is expanded outward. Thereby, the some light emitting element 10 obtained by cut
- the above-described first embodiment also relates to the plurality of scheduled cutting lines 51 set so as to be parallel to the a-plane and the back-surface 31b of the single crystal sapphire substrate 31 also by the workpiece cutting method of the second embodiment described above. The same effect as the method for cutting an object to be processed is obtained.
- the cutting line 52 is pressed by pressing the knife edge 44 against the workpiece 1 from the back surface 31 b side of the single crystal sapphire substrate 31 along each of the cutting lines 52.
- An external force is applied to the workpiece 1 along each of the above.
- an external force acts on the workpiece 1 so that the crack 82 reaching the surface 31a of the single crystal sapphire substrate 31 is opened. Therefore, the workpiece 1 is easily and accurately along the planned cutting line 52. Can be cut off.
- the laser beam L is irradiated to the workpiece 1 along each of the planned cutting lines 52 so as to satisfy ⁇ e, thereby forming the modified region 72 in the single crystal sapphire substrate 31 and generating from the modified region 72
- the crack 82 is made to reach the surface 31 a of the single crystal sapphire substrate 31.
- the crack 82 can be stored in the street region 38 on the surface 31 a of the single crystal sapphire substrate 31, and the crack 81 can be prevented from reaching the light emitting element portion 32. And especially the cutting quality of the element layer 33 can be improved by making the crack 82 generated from the modified region 72 reach the surface 31a of the single crystal sapphire substrate 31.
- e minimum allowable distance from the position where the condensing point P is aligned to the surface 31a: 50 ⁇ m
- t thickness of the single crystal sapphire substrate 31
- d width of the street region 38
- m t-[(d / 2) From ⁇ m] / tan ⁇ ⁇ Z ⁇ te, 30 ⁇ m ⁇ Z ⁇ 100 ⁇ m.
- the condensing point P of the laser beam L is aligned with the position in the single crystal sapphire substrate 31 that is 30 to 100 ⁇ m away from the back surface 31b, and the condensing point P can be relatively moved along the planned cutting line 52. That's fine.
- the modified region 71 is formed along the scheduled cutting line 51 as follows, it is not necessary to invert the processing object 1 in the process of cutting the processing object 1. That is, as shown in FIG. 17, the back surface 31b of the single crystal sapphire substrate 31 is used as the incident surface of the laser light L in the single crystal sapphire substrate 31, and the condensing point P of the laser light L is aligned in the single crystal sapphire substrate 31. The focusing point P is relatively moved along each of the scheduled cutting lines 51.
- the modified region 71 is formed in the single crystal sapphire substrate 31 along each of the planned cutting lines 51, and contrary to the case of the processing object cutting method of the first embodiment,
- the generated crack 81 is caused to reach the surface 31a of the single crystal sapphire substrate 31 (first step). At this time, the crack 81 does not reach the back surface 31b of the single crystal sapphire substrate 31, but extends from the modified region 71 to the back surface 31b side.
- the side formed by the acute angle between the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is one side, and the angle formed by the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is an obtuse angle.
- the condensing point P of the laser light L is set from the other side to the one side in all the scheduled cutting lines 51, contrary to the case of the workpiece cutting method of the first embodiment. Move relative.
- the distance from the position where the condensing point P is aligned to the surface 31a is, for example, a distance less than half the thickness of the single crystal sapphire substrate 31, and is, for example, 50 to 70 ⁇ m.
- the distance from the position where the condensing point P is aligned to the surface 31a should not be smaller than the allowable minimum distance e.
- the knife edge 44 is pressed against the workpiece 1 through the expanded tape 42 from the back surface 31 b side of the single crystal sapphire substrate 31 along each of the scheduled cutting lines 51 and 52.
- the workpiece 1 can be cut along each of the scheduled cutting lines 51 and 52. Thus, in the process of cutting the workpiece 1, it is not necessary to reverse the workpiece 1.
- the laser beam L is collected from the other side to the one side, contrary to the case of the processing object cutting method of the first embodiment.
- the meandering amount of the crack 81 reaching the surface 31a of the single crystal sapphire substrate 31 from the modified region 71 can be suppressed to be small.
- the r-plane of the single crystal sapphire substrate 31 and the surface are formed.
- the workpiece cutting method according to the third embodiment is different from the workpiece cutting method according to the first embodiment described above in the step of forming the modified regions 71 and 72.
- the processing object cutting method of the third embodiment will be described mainly with respect to the different steps.
- the back surface 31b of the single crystal sapphire substrate 31 is the incident surface of the laser light L on the single crystal sapphire substrate 31, and the single crystal sapphire substrate 31 separated from the back surface 31b by a distance (second distance) Zd1.
- the condensing point P of the laser beam L is aligned with the inner position, and the condensing point P is relatively moved along one cutting scheduled line 51.
- a modified region (third modified region) 73 is formed in the single crystal sapphire substrate 31 along the one scheduled cutting line 51.
- the crack (third crack) 83 generated from the modified region 73 does not reach the front surface 31a and the back surface 31b of the single crystal sapphire substrate 31, but extends from the modified region 73 to the front surface 31a side and the back surface 31b side. To do.
- the side where the angle formed between the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is an acute angle is one side, and the r-plane and the back surface 31b of the single crystal sapphire substrate 31 are If the other side is the side where the formed angle is an obtuse angle, the condensing point P is relatively moved from the other side to the one side along the one scheduled cutting line 51.
- the back surface 31b of the single crystal sapphire substrate 31 is used as the incident surface of the laser light L in the single crystal sapphire substrate 31, and the single crystal sapphire substrate 31 is separated from the back surface 31b by a distance (first distance) Zs1 smaller than the distance Zd1.
- the condensing point P of the laser beam L is aligned with the position of, and the condensing point P is relatively moved along the one scheduled cutting line 51.
- the modified region 71 is formed in the single crystal sapphire substrate 31 along the one scheduled cutting line 51, and the crack 81 generated from the modified region 71 is made to reach the back surface 31b.
- the crack 81 generated from the modified region 71 does not reach the surface 31a of the single crystal sapphire substrate 31, but extends from the modified region 71 to the surface 31a side.
- the side where the angle between the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is an acute angle is one side, and the r-plane and the back surface 31b of the single crystal sapphire substrate 31 are Assuming that the other side is an obtuse angle, the condensing point P is relatively moved from one side to the other side along the one scheduled cutting line 51.
- the above reformed regions 71 and 73 are sequentially formed for every planned cutting line 51 for each planned cutting line 51 (first step).
- the distance from the position where the condensing point P is aligned to the surface 31a is made not to be smaller than the allowable minimum distance e.
- the back surface 31b of the single crystal sapphire substrate 31 is used as the incident surface of the laser light L in the single crystal sapphire substrate 31, and is located at a position in the single crystal sapphire substrate 31 away from the back surface 31b by a distance Zd2.
- the condensing point P of the laser beam L is matched, and the condensing point P is relatively moved along one cutting scheduled line 52.
- a modified region (second modified region) 74 is formed in the single crystal sapphire substrate 31 along the one scheduled cutting line 52.
- the crack 84 generated from the modified region 74 does not reach the front surface 31a and the back surface 31b of the single crystal sapphire substrate 31, but extends from the modified region 74 to the front surface 31a side and the back surface 31b side.
- the workpiece 1 is cut along the planned cutting line 52, the surface of the single crystal sapphire substrate 31 even if the extension direction of the crack 84 generated from the modified region 74 is pulled in the direction of the r-plane inclination.
- the crack 84 can be accommodated in the street region 38 in 31a, and the crack 81 can be prevented from reaching the light emitting element portion 32.
- the back surface 31b of the single crystal sapphire substrate 31 is used as the incident surface of the laser light L on the single crystal sapphire substrate 31, and the laser light is positioned at a position in the single crystal sapphire substrate 31 that is separated from the back surface 31b by a distance Zs2 smaller than the distance Zd2.
- the condensing point P of L is put together, and the condensing point P is relatively moved along the one scheduled cutting line 52.
- the modified region 72 is formed in the single crystal sapphire substrate 31 along the one scheduled cutting line 52, and the crack 82 generated from the modified region 72 reaches the back surface 31b.
- the crack 82 generated from the modified region 72 does not reach the surface 31a of the single crystal sapphire substrate 31, but extends from the modified region 71 to the surface 31a side.
- the modified region 72 In forming the modified region 72, the inclined surface 45 and the back surface of each of the planned cutting lines 52 with respect to the inclined surface 45 that passes through the modified region 74 and is parallel to the r-plane of the single crystal sapphire substrate 31.
- the modified region 72 is positioned on the side where the angle formed with 31b is an acute angle. More specifically, when viewed from a direction perpendicular to the back surface 31b, the crack 82 reaching the back surface 31b is positioned on the center line CL (here, coincides with the planned cutting line 52) of the street region 38.
- the modified region 72 is positioned on the side away from the inclined surface 45 with respect to the center line CL. However, as shown in FIG.
- the crack 82 reaching the back surface 31b is located between the center line CL of the street region 38 and the inclined surface 45 reaching the back surface 31b.
- the modified region 72 may be positioned on the side closer to the inclined surface 45 with respect to the center line CL.
- the crack 82 reaching the back surface 31b is formed in the street region 38 or between the center line CL of the street region 38 and the inclined surface 45 reaching the back surface 31b.
- the modified region 72 may be formed along the planned cutting line 52 so as to be positioned.
- the above reformed regions 72 and 74 are formed sequentially for all the planned cutting lines 52 for each planned cutting line 52 (third step).
- the distance from the position where the condensing point P is aligned to the back surface 31b is, for example, a distance less than half the thickness of the single crystal sapphire substrate 31, and is, for example, 30 to 50 ⁇ m.
- the expanded tape 42 is attached to the workpiece 1 so as to cover the back surface 31b of the single crystal sapphire substrate 31.
- the three-point bending break device by pressing the knife edge 44 against the workpiece 1 via the protective tape 41 from the surface 31a side of the single crystal sapphire substrate 31 along each of the scheduled cutting lines 51, An external force is applied to the workpiece 1 along each of the scheduled cutting lines 51. Thereby, the crack 81 generated from the modified region 71 and the crack 83 generated from the modified region 73 are extended, and the workpiece 1 is cut into a bar shape along each of the scheduled cutting lines 51 (second). Process).
- the knife edge 44 is pressed against the workpiece 1 via the protective tape 41 from the surface 31a side of the single crystal sapphire substrate 31 along each of the planned cutting lines 52.
- An external force is applied to the workpiece 1 along the line.
- the crack 82 generated from the modified region 72 and the crack 84 generated from the modified region 74 are extended to the surface 31a side, and the workpiece 1 is cut into chips along each of the planned cutting lines 52. (4th process).
- the protective tape 41 is removed from the workpiece 1 and the expanded tape 42 is expanded outward. Thereby, the some light emitting element 10 obtained by cut
- the above-described first embodiment also relates to the plurality of scheduled cutting lines 51 set so as to be parallel to the a-surface and the back surface 31b of the single crystal sapphire substrate 31 also by the workpiece cutting method of the third embodiment described above. The same effect as the method for cutting an object to be processed is obtained.
- the modified region 73 is formed for each planned cutting line 51, and then the modified region 71 is formed continuously. Then, the condensing point P of the laser beam L is moved in the opposite direction when the modified region 73 is formed and when the modified region 71 is formed. Thereby, the condensing point P of the laser beam L can be moved efficiently. More specifically, the condensing point P that is relatively moved from the other side to the one side when forming the modified region 73 in the one scheduled cutting line 51 forms the modified region 71. In this case, the relative movement from one side to the other side returns to the other side. Therefore, the irradiation of the laser beam L can be started quickly in the scheduled cutting line 51 adjacent to the one scheduled cutting line 51.
- the workpiece 1 can be cut with high accuracy.
- the pulse energy of the laser beam L for forming one of the modified regions 71 and 73 and one of the modified regions 72 and 74 can be reduced, the light emitting element portion is caused by the irradiation of the laser beam L. It is possible to prevent the characteristics of 32 from deteriorating.
- the cutting scheduled line is formed by pressing the knife edge 44 against the workpiece 1 from the surface 31 a side of the single crystal sapphire substrate 31 along each of the scheduled cutting lines 51 and 52.
- An external force is applied to the workpiece 1 along each of 51 and 52.
- an external force acts on the workpiece 1 so that the cracks 81 and 82 that have reached the back surface 31b of the single crystal sapphire substrate 31 are opened, so that the cutting target lines 51 and 52 can be easily and accurately aligned.
- the workpiece 1 can be cut.
- each of the plurality of scheduled cutting lines 52 set to be parallel to the m-plane and the back surface 31b of the single crystal sapphire substrate 31 passes through the modified region 74 and extends to the r-plane of the single crystal sapphire substrate 31.
- the modified region 72 is positioned on the side where the angle formed by the inclined surface 45 and the back surface 31b becomes an acute angle with respect to the parallel inclined surface 45.
- the crack 84 extending from the modified region 74 to the back surface 31b side extends to the modified region 72 side
- the crack 82 extending from the modified region 72 to the surface 31a side extends to the modified region 74 side.
- the crack 84 and the crack 82 are connected in the single crystal sapphire substrate 31.
- the crack 84 generated from the modified region 74 on the front surface 31a side is suppressed from extending to the front surface 31a of the single crystal sapphire substrate 31 while the crack 82 generated from the modified region 72 on the back surface 31b side is suppressed to the street region 38. It is possible to prevent the cracks 82 and 84 from reaching the light emitting element portion 32.
- the processing object cutting method of the first to third embodiments of the present invention has been described above. However, the processing object cutting method of the present invention is limited to the processing object cutting method of the first to third embodiments. It is not something.
- the laser is changed from the side where the angle between the r-plane and the back surface 31b of the single crystal sapphire substrate 31 is an obtuse angle to the side where the angle is an acute angle.
- the crack 81 generated from the modified region 71 when the modified region 71 is formed may not reach the back surface 31b. Also in these cases, it is possible to suppress a change in the meandering amount of the crack 81 generated from the modified region 71 formed along each of the scheduled cutting lines 51. At least this effect is exhibited regardless of how the modified region is formed along the planned cutting line 52.
- the single crystal sapphire substrate 31 when the single crystal sapphire substrate 31 is relatively thick, etc., a plurality of rows (not limited to two rows, depending on the case) Three or more modified regions may be formed.
- the angle formed between the r-plane of the single crystal sapphire substrate 31 and the back surface 31b is an obtuse angle from the side that becomes an acute angle. If the condensing point P of the laser beam L is relatively moved to the side, the modification closest to the back surface 31b compared to the case where the condensing point P of the laser beam L is relatively moved in the opposite direction.
- the meandering amount of the crack 81 reaching the back surface 31b of the single crystal sapphire substrate 31 from the region 71 can be suppressed to a small value.
- the other modified region such as the modified region 73 is formed from one side to the other along the planned cutting line 51.
- the condensing point P of the laser beam L may be moved relatively to the side of the laser beam L. In this way, the condensing point P of the laser beam L is moved in the same direction when the modified region 71 is formed and when the modified region 73 is formed, so that the crack 81 is simply formed when the modified region 71 is formed.
- the back surface 31b of the crystal sapphire substrate 31 can be reliably reached.
- the modified regions are continuously formed for each scheduled cutting line, and this is sequentially performed for all the scheduled cutting lines. May be.
- the modified region located at the same distance from the back surface 31b may be continuously formed, and then another modified region located at the same distance from the back surface 31b may be continuously formed.
- This step may be performed first.
- Either step may be performed first.
- the support base 107 of the laser processing apparatus 100 may be moved, or the laser processing apparatus 100 may be moved.
- the laser light source 101 side (the laser light source 101, the dichroic mirror 103, the condensing lens 105, etc.) may be moved, or both the support base 107 and the laser light source 101 side may be moved.
- the workpiece 1 includes a single crystal sapphire substrate 31, an n-type semiconductor layer (first conductivity type semiconductor layer) 34 stacked on the surface 31 a of the single crystal sapphire substrate 31, and an n-type semiconductor layer 34. And an p-type semiconductor layer (second conductivity type semiconductor layer) 35 laminated on the active layer.
- the n-type semiconductor layer 34, the active layer, and the p-type semiconductor layer 35 are made of a III-V group compound semiconductor such as GaN, for example, and constitute a quantum well structure.
- the element layer 33 may further include a contact layer for electrical connection with the electrode pads 36 and 37.
- the first conductivity type may be p-type and the second conductivity type may be n-type.
- the off-angle of the single crystal sapphire substrate 31 may be 0 °. In this case, the front surface 31a and the back surface 31b of the single crystal sapphire substrate 31 are parallel to the c-plane.
Abstract
Description
[第1実施形態]
[第2実施形態]
[第3実施形態]
Claims (6)
- c面とオフ角分の角度を成す表面及び裏面を有する単結晶サファイア基板と、前記表面上にマトリックス状に配列された複数の発光素子部を含む素子層と、を備える加工対象物を前記発光素子部ごとに切断して複数の発光素子を製造するための加工対象物切断方法であって、
前記裏面を前記単結晶サファイア基板におけるレーザ光の入射面として、前記裏面から第1距離だけ離れた前記単結晶サファイア基板内の位置に前記レーザ光の集光点を合わせて、前記単結晶サファイア基板のa面及び前記裏面に平行となるように設定された複数の第1切断予定ラインのそれぞれに沿って一方の側から他方の側に前記集光点を相対的に移動させることにより、前記第1切断予定ラインのそれぞれに沿って前記単結晶サファイア基板内に第1改質領域を形成する第1工程と、
前記第1工程の後に、前記第1切断予定ラインのそれぞれに沿って前記加工対象物に外力を作用させることにより、前記第1改質領域から発生した第1亀裂を伸展させて、前記第1切断予定ラインのそれぞれに沿って前記加工対象物を切断する第2工程と、を備える、加工対象物切断方法。 - 前記第1工程では、前記単結晶サファイア基板のr面と前記裏面との成す角度が鋭角となる側を前記一方の側とし、且つ前記r面と前記裏面との成す角度が鈍角となる側を前記他方の側として、前記第1切断予定ラインのそれぞれに沿って前記一方の側から前記他方の側に前記集光点を相対的に移動させることにより、前記第1切断予定ラインのそれぞれに沿って前記単結晶サファイア基板内に前記第1改質領域を形成すると共に、前記第1亀裂を前記裏面に到達させる、請求項1記載の加工対象物切断方法。
- 前記第2工程では、前記第1切断予定ラインのそれぞれに沿って前記表面側から前記加工対象物にナイフエッジを押し当てることにより、前記第1切断予定ラインのそれぞれに沿って前記加工対象物に外力を作用させる、請求項2記載の加工対象物切断方法。
- 前記第2工程の前に、前記裏面を前記入射面として、前記単結晶サファイア基板内に前記集光点を合わせて、前記単結晶サファイア基板のm面及び前記裏面に平行となるように設定された複数の第2切断予定ラインのそれぞれに沿って前記集光点を相対的に移動させることにより、前記第2切断予定ラインのそれぞれに沿って前記単結晶サファイア基板内に第2改質領域を形成する第3工程と、
前記第1工程及び前記第3工程の後に、前記第2切断予定ラインのそれぞれに沿って前記加工対象物に外力を作用させることにより、前記第2改質領域から発生した第2亀裂を伸展させて、前記第2切断予定ラインのそれぞれに沿って前記加工対象物を切断する第4工程と、を更に備える、請求項1~3のいずれか一項記載の加工対象物切断方法。 - 前記第1工程では、前記裏面を前記入射面として、前記裏面から前記第1距離よりも大きい第2距離だけ離れた前記単結晶サファイア基板内の位置に前記集光点を合わせて、前記第1切断予定ラインのそれぞれに沿って前記他方の側から前記一方の側に前記集光点を相対的に移動させることにより、前記第1切断予定ラインのそれぞれに沿って前記単結晶サファイア基板内に第3改質領域を形成し、
前記第2工程では、前記第1切断予定ラインのそれぞれに沿って前記加工対象物に外力を作用させることにより、前記第1亀裂、及び前記第3改質領域から発生した第3亀裂を伸展させて、前記第1切断予定ラインのそれぞれに沿って前記加工対象物を切断する、請求項1~4のいずれか一項記載の加工対象物切断方法。 - 前記第1工程では、前記裏面を前記入射面として、前記裏面から前記第1距離よりも大きい第2距離だけ離れた前記単結晶サファイア基板内の位置に前記集光点を合わせて、前記第1切断予定ラインのそれぞれに沿って前記一方の側から前記他方の側に前記集光点を相対的に移動させることにより、前記第1切断予定ラインのそれぞれに沿って前記単結晶サファイア基板内に第3改質領域を形成し、
前記第2工程では、前記第1切断予定ラインのそれぞれに沿って前記加工対象物に外力を作用させることにより、前記第1亀裂、及び前記第3改質領域から発生した第3亀裂を伸展させて、前記第1切断予定ラインのそれぞれに沿って前記加工対象物を切断する、請求項1~4のいずれか一項記載の加工対象物切断方法。
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