JP5104919B2 - Laser processing apparatus, workpiece processing method, and workpiece dividing method - Google Patents

Laser processing apparatus, workpiece processing method, and workpiece dividing method Download PDF

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JP5104919B2
JP5104919B2 JP2010166229A JP2010166229A JP5104919B2 JP 5104919 B2 JP5104919 B2 JP 5104919B2 JP 2010166229 A JP2010166229 A JP 2010166229A JP 2010166229 A JP2010166229 A JP 2010166229A JP 5104919 B2 JP5104919 B2 JP 5104919B2
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workpiece
cleavage
stage
irradiated
processing
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JP2012024815A (en
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正平 長友
郁祥 中谷
充 菅田
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三星ダイヤモンド工業株式会社
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/36Removing material
    • B23K26/38Removing material by boring or cutting
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/062Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
    • B23K26/0622Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
    • B23K26/0624Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses using ultrashort pulses, i.e. pulses of 1ns or less
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/08Devices involving relative movement between laser beam and workpiece
    • B23K26/083Devices involving movement of the workpiece in at least one axial direction
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/70Auxiliary operations or equipment
    • B23K26/702Auxiliary equipment
    • B23K26/703Cooling arrangements
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K37/00Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups
    • B23K37/04Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups for holding or positioning work
    • B23K37/0408Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups for holding or positioning work for planar work
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2101/00Articles made by soldering, welding or cutting
    • B23K2101/36Electric or electronic devices

Description

  The present invention relates to a laser processing method for processing a workpiece by irradiating a laser beam and a laser processing apparatus used therefor.

  Various techniques (hereinafter simply referred to as laser processing or laser processing technology) for processing a workpiece by irradiating pulsed laser light are already known (see, for example, Patent Document 1 to Patent Document 4).

  Patent Document 1 discloses that when a die as a workpiece is divided, a groove having a V-shaped cross section (break groove) is formed along a planned dividing line by laser ablation, and the die is started from this groove. Is a method of dividing On the other hand, Patent Document 2 discloses that a laser beam in a defocused state is irradiated along a planned division line of an object to be processed (divided object), so that the irradiated region is less crystallized than the surroundings. In this method, a melt-modified region (modified region) having a substantially V-shaped cross section is generated, and the workpiece is divided starting from the lowest point of the melt-modified region.

  In any case where the division starting points are formed using the techniques disclosed in Patent Document 1 and Patent Document 2, the subsequent division is performed satisfactorily, so that it is uniform along the planned division line direction that is the scanning direction of the laser light. It is important to form a V-shaped cross section (groove cross section or altered region cross section) having a simple shape. For this purpose, for example, the irradiation of the laser beam is controlled so that the irradiated region (beam spot) of the laser beam for each pulse overlaps before and after.

  For example, when the repetition frequency (unit: kHz), which is the most basic parameter of laser processing, is R, and the scanning speed (unit: mm / sec) is V, the ratio V / R of both is the center distance of the beam spot. However, in the techniques disclosed in Patent Document 1 and Patent Document 2, laser light irradiation and scanning are performed under the condition that V / R is 1 μm or less so that beam spots overlap each other.

  Further, in Patent Document 3, a modified region is formed inside the substrate by aligning a condensing point inside the substrate having a laminated portion on the surface and irradiating laser light, and this modified region is defined as a starting point of cutting. An embodiment is disclosed.

  Further, in Patent Document 4, a laser beam scan is repeated a plurality of times for one separation line to deepen a groove portion and a modification portion that are continuous in the separation line direction and an internal modification portion that is not continuous in the separation line direction. The aspect formed in the up-down direction is disclosed.

  On the other hand, Patent Document 5 discloses a processing technique using an ultrashort pulse laser beam having a pulse width of the order of psec, and by adjusting the focused spot position of the pulse laser beam, a workpiece (plate). A mode is disclosed in which minute dissolution marks are formed in which micro cracks are clustered from the surface layer portion to the surface, and a linear separation facilitating region in which these dissolution marks are connected is disclosed.

JP 2004-9139 A International Publication No. 2006/062017 JP 2007-83309 A JP 2008-98465 A JP 2005-271563 A

  The method of forming the split starting point with laser light and then splitting with a breaker is more automated, faster, more stable and more accurate than diamond scribing, which is a conventional mechanical cutting method. Is advantageous in terms of sex.

  However, when the division starting point is formed by the laser beam by the conventional method, it is inevitable that a so-called processing mark (laser processing mark) is formed in the portion irradiated with the laser beam. A processing mark is a denatured region in which the material or structure has changed as a result of irradiation with laser light. It is preferable to suppress the formation of the processing marks as much as possible in order to adversely affect the characteristics of each of the divided workpieces (divided pieces).

  For example, a workpiece in which a light emitting element structure such as an LED structure is formed on a substrate made of a hard and brittle and optically transparent material such as sapphire is processed by conventional laser processing as disclosed in Patent Document 2. In the edge portion of the light emitting element obtained by dividing into chips (the portion that has been irradiated with laser light during division), the width is about several μm and the depth is about several μm to several tens of μm. Traces are formed continuously. Such a processing mark absorbs light generated inside the light emitting element, and there is a problem in that light extraction efficiency from the element is reduced. In particular, the problem associated with the light emitting device structure using a sapphire substrate having a high refractive index is significant.

  The inventor of the present invention, as a result of intensive studies, in forming the division starting point by irradiating the workpiece with laser light, by utilizing the cleavage property or cleavage property of the workpiece, It was found that the formation of is suitably suppressed. In addition, the inventors have found that it is preferable to use ultrashort pulse laser light for such processing.

  In Patent Document 1 to Patent Document 5, there is no disclosure or suggestion about the formation mode of the division starting point that utilizes the cleavage property or cleavage property of the workpiece.

  On the other hand, when the division starting point is formed using laser light and the process of dividing the workpiece into chips is performed, the tip of the dividing starting point reaches as deep as possible in the workpiece. This is preferable because the certainty of division is increased. The same applies to the case where ultrashort pulse laser light is used.

  The present invention has been made in view of the above-described problems, and it is possible to form a division starting point that enables formation of a division starting point that suppresses the formation of machining traces and more reliably realizes division of the workpiece. It is an object of the present invention to provide a method and a laser processing apparatus used therefor.

In order to solve the above problems, the invention of claim 1 is a laser processing apparatus including a light source that emits pulsed laser light and a stage on which a workpiece is placed, and is placed on the stage. The pulse laser is further provided with a cooling mechanism for cooling the placement surface of the workpiece, the workpiece is placed on the stage, and the placement surface is cooled by the cooling mechanism. At least two irradiated areas formed by different unit pulse lights so that the irradiated areas for each individual unit pulsed light of light are discretely formed on the processing surface facing the mounting surface described above but the next to each other in the cleavage or parting easy direction of the workpiece, by irradiating the pulsed laser beam while moving said stage in said workpiece, said to be illuminated By giving sequentially generate cleavage or parting of the workpiece between the band between said forms a starting point for splitting the workpiece, characterized in that.

Invention of Claim 2 is a laser processing apparatus provided with the light source which emits a pulse laser beam, and the stage in which a workpiece is mounted, Comprising: The mounting surface of the said workpiece mounted in the said stage A cooling mechanism for cooling the unit, each unit pulse light of the pulse laser light is placed in a state where the workpiece is placed on the stage and the placement surface is cooled by the cooling mechanism. At least two irradiated areas formed by different unit pulse lights so as to irradiate the processing surface facing the mounting surface discretely , and in the direction in which the workpiece is easily cleaved or cleaved as adjacent in, while moving the stage irradiating the pulsed laser beam on the workpiece, depending on the impact or stress when the individual unit pulsed beam is irradiated to the irradiation position By causing cleavage or parting between the irradiated position of the unit pulsed beam irradiated immediately before or at the same time, the form the starting point for the division in the workpiece, characterized in that.
A third aspect of the present invention is the laser processing apparatus according to the first or second aspect, wherein the at least two irradiated regions are formed by two easy cleaving or cleaving of the workpieces. It is characterized by alternately performing in the direction.
Invention of Claim 4 is a laser processing apparatus of Claim 1 or Claim 2, Comprising: All the said to-be-irradiated area | regions are formed along the easy cleavage or cleavage direction of the said to-be-processed object. It is characterized by.
The invention of claim 5 is a laser processing apparatus comprising: a light source that emits pulsed laser light; and a stage on which the workpiece is placed, and the placement surface of the workpiece placed on the stage A cooling mechanism for cooling the unit, each unit pulse light of the pulse laser light in a state where the workpiece is placed on the stage and the placement surface is cooled by the cooling mechanism. The pulsed laser beam while moving the stage so that the irradiated area of the workpiece is discretely formed on the workpiece surface in an equivalent direction to two different cleavage or cleavage easy directions of the workpiece. Is applied to the workpieces to sequentially cause cleavage or cleavage of the workpieces between the irradiated regions, thereby forming a starting point for division in the workpieces. It is characterized in.
The invention of claim 6 is a laser processing apparatus comprising: a light source that emits pulsed laser light; and a stage on which the workpiece is placed, and the placement surface of the workpiece placed on the stage A cooling mechanism for cooling the unit, each unit pulse light of the pulse laser light is placed in a state where the workpiece is placed on the stage and the placement surface is cooled by the cooling mechanism. The pulse laser beam is applied to the workpiece surface while moving the stage so that the workpiece is discretely irradiated in a direction equivalent to two different cleavage or cleavage easy directions of the workpiece on the workpiece surface. Cleavage between the irradiation position of the unit pulse light irradiated immediately before or simultaneously with the impact or stress when the irradiation with the unit pulse light is irradiated to the irradiation position is performed on the workpiece. Ku by causing tearing, said to form a starting point for the division in the workpiece, characterized in that.

The invention of claim 7 is a claims 1 laser processing apparatus according to claim 6, wherein the pulsed laser light, the pulse width is ultrashort pulse light psec order, and characterized in that To do.

The invention according to claim 8 is the laser processing apparatus according to any one of claims 1 to 7 , wherein at least when the pulse laser beam is irradiated onto the workpiece, the cooling mechanism is provided on the stage. It is arrange | positioned below, The said mounting surface is cooled when the said cooling mechanism cools the said stage from the downward direction, It is characterized by the above-mentioned.

A ninth aspect of the present invention is the laser processing apparatus according to the eighth aspect , wherein the cooling mechanism includes a Peltier element, and at least when the pulse laser beam is irradiated onto the workpiece, the Peltier element is The placement surface is cooled by cooling the stage with the Peltier element in a state of being arranged close to the stage.

A tenth aspect of the present invention is the laser processing apparatus according to the eighth or ninth aspect , wherein a digging portion is provided below the stage, and the cooling mechanism is connected to the stage at the digging portion. It arrange | positions so that it may adjoin.

The invention of claim 11 is a processing method for forming a division starting point on a workpiece, comprising: a mounting step of mounting the workpiece on a stage; and a mounting surface of the workpiece on the stage. By irradiating the workpiece with the pulsed laser light in a cooled state so that the irradiated region for each unit pulsed light is discretely formed on the processing surface facing the mounting surface. An irradiation step of forming a starting point for division on the workpiece by sequentially causing cleavage or cleavage of the workpiece between the irradiated regions, and in the irradiation step Is characterized in that at least two irradiated regions formed by different unit pulse lights are formed adjacent to each other in the direction of easy cleavage or cleavage of the workpiece .

The invention of claim 12 is a processing method for forming a division starting point on a workpiece, wherein a mounting step of mounting the workpiece on a stage, and a mounting surface of the workpiece on the stage are provided. In a cooled state, the pulse laser beam is applied to the workpiece so that each unit pulse beam is discretely irradiated to the workpiece surface facing the mounting surface, and the individual unit pulse beams are irradiated. Is divided into the workpiece by causing cleavage or cleavage between the irradiation position of the unit pulse light irradiated immediately before or simultaneously due to impact or stress when the irradiation position is irradiated to the irradiation position. and an irradiation step of forming a starting point for, in the irradiation step, at least two irradiation regions are formed by different said unit pulsed beams, the cleavage or parting easy axis of the workpiece There formed to so as to be adjacent to, and wherein the.
Invention of Claim 13 is the processing method of Claim 11 or Claim 12, Comprising: In the said irradiation process, formation of the said at least 2 to-be-irradiated area | region is two said different said workpieces. It is characterized by being alternately performed in the direction of easy cleavage or cleavage.
The invention of claim 14 is the processing method according to claim 11 or claim 12, wherein, in the irradiation step, all the irradiated regions are arranged along a direction in which the workpiece is easily cleaved or cleaved. It is characterized by forming.
A fifteenth aspect of the present invention is the processing method according to any one of the eleventh to thirteenth aspects, wherein, in the irradiation step, the pulse laser beam emission source and the workpiece are moved relative to each other. The pulsed laser beam emission direction is periodically changed in a plane perpendicular to the relative movement direction, thereby forming a plurality of irradiated regions that have a staggered arrangement relationship on the workpiece. It is characterized by that.
A sixteenth aspect of the present invention is the processing method according to any one of the eleventh to thirteenth aspects, wherein in the irradiation step, the plurality of pulsed laser light emission sources and the workpiece are relatively moved. While forming the plurality of irradiated regions that meet the staggered arrangement relationship on the workpiece by periodically changing the irradiation timing of the unit pulse light from each of the plurality of emission sources, It is characterized by that.
The invention according to claim 17 is a processing method for forming a division starting point on a workpiece, and includes a mounting step of mounting the workpiece on a stage, and a mounting surface of the workpiece on the stage. By irradiating the workpiece with the pulsed laser light in a cooled state so that the irradiated region for each unit pulsed light is discretely formed on the processing surface facing the mounting surface. An irradiation step of forming a starting point for division on the workpiece by sequentially causing cleavage or cleavage of the workpiece between the irradiated regions, and in the irradiation step Is characterized in that the irradiated region is formed in a direction equivalent to two different cleavage or cleavage easy directions of the workpiece.
The invention according to claim 18 is a processing method for forming a division starting point on a workpiece, comprising: a mounting step of mounting the workpiece on a stage; and a mounting surface of the workpiece on the stage. In a cooled state, the pulse laser beam is applied to the workpiece so that each unit pulse beam is discretely irradiated to the workpiece surface facing the mounting surface, and the individual unit pulse beams are irradiated. Is divided into the workpiece by causing cleavage or cleavage between the irradiation position of the unit pulse light irradiated immediately before or simultaneously due to impact or stress when the irradiation position is irradiated to the irradiation position. An irradiation step for forming a starting point for forming the irradiation area, wherein in the irradiation step, the irradiated region is formed in an equivalent direction to two different cleavage or cleavage easy directions of the workpiece. This The features.

The invention of claim 19 is a processing method according to any one of claims 11 to claim 18, wherein the pulsed laser light, the pulse width is ultrashort pulse light psec order, characterized in that .

The invention of claim 20 is the processing method according to any one of claims 11 to 19 , wherein, in the irradiation step, the cooling mechanism is disposed below the stage, and the stage is moved by the cooling mechanism. The mounting surface is cooled by cooling from below.

The invention according to claim 21 is the processing method according to claim 20 , wherein the cooling mechanism includes a Peltier element, and in the irradiation step, the Peltier element is disposed in proximity to the stage by the Peltier element. The mounting surface is cooled by cooling the stage.

  The invention of claim 22 is a method of dividing a workpiece, wherein the workpiece on which a division starting point is formed by the method according to any one of claims 11 to 21 is arranged along the division starting point. It is characterized by dividing.

  According to the inventions of claims 1 to 22, the formation of machining traces due to the alteration of the workpiece and the scattering of the workpiece are kept to be local, while the workpiece is actively cleaved or cleaved. As a result, the division starting point can be formed on the workpiece at a much higher speed than in the prior art. In addition, by cooling the mounting surface of the workpiece, the energy of the pulsed laser beam can be more efficiently contributed to the formation of the division start point, so that the tip of the division start point can be reached deeper. .

In particular, according to the invention of claim 3 , claim 5, claim 6 , claim 13 and claim 15 to claim 18 , the divided cross section when the workpiece is divided along the formed division starting point. And the division | segmentation starting point can be formed so that the unevenness | corrugation by adjacent cleavage or cleavage surface may be formed in the surface vicinity of a workpiece. When the work piece is a substrate made of a light and brittle and optically transparent material such as sapphire and a light emitting element structure such as an LED structure is formed, such a concavo-convex shape on the divided cross section of the substrate By forming the light emitting element, the light emission efficiency of the light emitting element can be improved.

It is a figure for demonstrating the process by a 1st process pattern. It is an optical microscope image about the surface of the to-be-processed object which formed the division | segmentation starting point by the cleavage / cleaving process by a 1st process pattern. It is a SEM image from the surface (c surface) to a section after dividing a sapphire C surface substrate which formed a division starting point by processing concerning the 1st processing pattern along this division starting point. It is a figure which shows typically the processing mode by a 2nd processing pattern. It is an optical microscope image about the surface of the to-be-processed object which formed the division | segmentation origin by the cleavage / cleaving process by a 2nd process pattern. It is a SEM image from the surface (c surface) to a section after dividing a sapphire c plane substrate which formed a division starting point by processing concerning the 2nd processing pattern along this division starting point. It is a figure which shows typically the processing mode by the 3rd processing pattern. It is a figure which shows the relationship between the process planned line in the 3rd process pattern, and the formation planned position of a to-be-irradiated area. It is a schematic diagram which shows roughly the structure of the laser processing apparatus 50 which concerns on embodiment of this invention. 2 is a schematic view illustrating the configuration of an optical system 5. FIG. It is a figure which shows typically the structure of the optical path setting means 5c. FIG. 4 is a diagram illustrating the configuration and arrangement position of a cooling mechanism 60.

<Processing principle>
First, the principle of processing realized in the following embodiment of the present invention will be described. In general, the processing performed in the present invention is performed by irradiating the upper surface (processing surface) of a workpiece while scanning with a pulsed laser beam (hereinafter, also simply referred to as laser beam). The workpiece is cleaved or cleaved in sequence between the irradiated areas, and the starting point (dividing starting point) for splitting is formed as a continuous surface of the cleaved surface or cleaved surface formed in each. Is.

  Note that in this embodiment mode, cleavage refers to a phenomenon in which a workpiece is cracked substantially regularly along a crystal plane other than the cleavage plane, and the crystal plane is referred to as a cleavage plane. In addition to cleaving and cleaving that are microscopic phenomena completely along the crystal plane, cracks that are macroscopic cracks may occur along a substantially constant crystal orientation. Depending on the substance, only one of cleavage, cleaving, or cracking mainly occurs, but in the following, in order to avoid complicated explanation, cleavage / cleavage is not distinguished from each other without distinguishing cleavage, cleaving, and cracking. Collectively called open. Further, the above-described processing may be simply referred to as cleavage / dehiscence processing or the like.

  In the following, an example will be described in which the workpiece is a hexagonal single crystal substance, and the directions of the a1 axis, a2 axis, and a3 axis are cleavage / cleavage easy directions. For example, a c-plane sapphire substrate corresponds to this. The a1 axis, a2 axis, and a3 axis of the hexagonal crystal are symmetric with each other at an angle of 120 ° in the c plane. The machining according to the present invention has several patterns depending on the relationship between the direction of these axes and the direction of the planned machining line (the planned machining direction). Hereinafter, these will be described. In the following, the laser light irradiated for each individual pulse is referred to as unit pulse light.

<First processing pattern>
The first processing pattern is an aspect of cleavage / dehissing processing when any of the a1 axis direction, the a2 axis direction, and the a3 axis direction is parallel to the planned processing line. More generally speaking, this is a processing mode in the case where the cleavage / cleavage easy direction matches the direction of the planned processing line.

  FIG. 1 is a diagram schematically showing a processing mode by the first processing pattern. FIG. 1 illustrates the case where the a1 axis direction and the planned machining line L are parallel. FIG. 1A is a diagram illustrating an azimuth relationship between the a1 axis direction, the a2 axis direction, the a3 axis direction, and the planned processing line L in such a case. FIG. 1B shows a state in which the unit pulse light of the first pulse of the laser light is irradiated to the irradiated region RE1 at the end of the processing line L.

  In general, irradiation with unit pulse light gives high energy to a very small region of the workpiece, and therefore, such irradiation is equivalent to the irradiation region of the unit pulse light (laser light) on the surface to be irradiated or the target. It causes alteration, melting, evaporative removal, etc. of substances in a range wider than the irradiation area.

  However, if the irradiation time of the unit pulse light, that is, the pulse width is set to be extremely short, a substance that is narrower than the spot size of the laser light and exists in the substantially central region of the irradiated region RE1 obtains kinetic energy from the irradiated laser light. While being scattered or altered in a direction perpendicular to the irradiated surface, the impact and stress generated by the irradiation of unit pulse light including reaction force caused by the scattering are around the irradiated region, In particular, it acts in the a1 axis direction, the a2 axis direction, and the a3 axis direction, which are easy cleavage / cleavage directions. As a result, micro-cleavage or cleaving partially occurs along the direction while maintaining an apparent contact state, or thermal distortion is inherent even without cleaving or cleaving. A state occurs. In other words, it can be said that the irradiation with the ultra-short pulse unit pulse light acts as a driving force for forming a weak intensity portion that is substantially linear in a top view toward the cleavage / cleavage easy direction.

  In FIG. 1 (b), the weak strength portion W1 in the + a1 direction that coincides with the extending direction of the planned processing line L among the weak strength portions formed in each of the above cleavage / cleavage easy directions is schematically shown by a broken line arrow. Is shown.

  Subsequently, as shown in FIG. 1C, the second unit pulse light of the laser light is irradiated, and the irradiated region RE2 is located on the processing planned line L at a position away from the irradiated region RE1 by a predetermined distance. As in the case of the first pulse, a weak intensity portion is formed in the second pulse along the easy cleavage / cleavage direction. For example, the weak strength portion W2a is formed in the −a1 direction, and the weak strength portion W2b is formed in the + a1 direction.

  However, at this time, the weak intensity portion W1 formed by the irradiation of the unit pulse light of the first pulse exists in the extending direction of the weak intensity portion W2a. That is, the extending direction of the weak strength portion W2a is a location where cleavage or cleavage can occur with less energy than other locations. Therefore, actually, when the unit pulse light of the second pulse is irradiated, the impact or stress generated at that time propagates to the easy-cleavage / cleavage direction and the weak intensity part existing ahead, and the weak intensity part From W2a to the weak intensity portion W1, complete cleavage or cleavage occurs almost at the moment of irradiation. As a result, a cleavage / cleavage plane C1 shown in FIG. 1 (d) is formed. The cleavage / cleavage surface C1 can be formed to a depth of about several μm to several tens of μm in the direction perpendicular to the drawing of the workpiece. Moreover, as will be described later, on the cleavage / cleavage plane C1, as a result of receiving a strong impact or stress, the crystal plane slips and undulations occur in the depth direction.

  Then, as shown in FIG. 1 (e), the irradiated regions RE1, RE2, RE3, RE4,... Are sequentially irradiated with unit pulse light by scanning the laser light along the planned processing line L. As a result, cleavage / cleavage surfaces C2, C3,... Are sequentially formed accordingly. It is the cleavage / dehissing process in the first machining pattern that continuously forms the cleavage / dehiscence surface in such a manner.

  That is, in the first processing pattern, a plurality of irradiated regions that exist discretely along the planned processing line L and the cleavage / cleavage surfaces formed between the plurality of irradiated regions as a whole This is the starting point for dividing the workpiece along the planned machining line L. After the formation of the division starting point, the workpiece can be divided in a mode generally along the planned processing line L by performing division using a predetermined jig or apparatus.

  In order to realize such cleavage / cleavage processing, it is necessary to irradiate a short pulse laser beam with a short pulse width. Specifically, it is necessary to use laser light having a pulse width of 100 psec or less. For example, it is preferable to use laser light having a pulse width of about 1 psec to 50 psec.

  On the other hand, the irradiation pitch of unit pulse light (center distance of irradiated spots) may be determined in the range of 4 μm to 50 μm. If the irradiation pitch is larger than this, the formation of the weak strength portion in the cleavage / cleavage easy direction may not progress to such an extent that a cleavage / cleavage surface can be formed. From the viewpoint of reliably forming the division starting point consisting of In view of scanning speed, processing efficiency, and product quality, it is preferable that the irradiation pitch is large. However, in order to make the formation of the cleavage / cleavage surface more reliable, it is determined within the range of 4 to 30 μm. Desirably, it is more preferably about 4 μm to 15 μm.

  Now, when the repetition frequency of laser light is R (kHz), unit pulse light is emitted from the laser light source every 1 / R (msec). When the laser beam moves relative to the workpiece at a speed V (mm / sec), the irradiation pitch Δ (μm) is determined by Δ = V / R. Therefore, the scanning speed V and the repetition frequency of the laser beam are determined so that Δ is about several μm. For example, the scanning speed V is preferably about 50 mm / sec to 3000 mm / sec, and the repetition frequency R is preferably about 1 kHz to 200 kHz, particularly about 10 kHz to 200 kHz. Specific values of V and R may be appropriately determined in consideration of the material of the workpiece, the absorption rate, the thermal conductivity, the melting point, and the like.

The laser beam is preferably irradiated with a beam diameter of about 1 μm to 10 μm. In such a case, the peak power density upon laser light irradiation is approximately 0.1 TW / cm 2 to several tens TW / cm 2 .

  Further, the laser beam irradiation energy (pulse energy) may be appropriately determined within the range of 0.1 μJ to 50 μJ.

  FIG. 2 is an optical microscope image of the surface of the workpiece on which the division starting points are formed by the cleavage / cleavage processing in the first processing pattern. Specifically, the sapphire c-plane substrate is a workpiece, and on the c-plane, processing is performed to discretely form irradiated spots at intervals of 7 μm with the a1 axis direction as the extending direction of the processing line L. The results are shown. The result shown in FIG. 2 suggests that the actual workpiece is processed by the mechanism described above.

  Further, FIG. 3 shows an SEM (scanning electron microscope) from the surface (c-plane) to the cross-section after dividing the sapphire c-plane substrate on which the division starting points are formed by the processing according to the first processing pattern along the division starting points. ) In FIG. 3, the boundary portion between the surface and the cross section is indicated by a broken line.

  The elongated triangular or needle-like region having a longitudinal direction from the surface of the workpiece, which is present in the range of about 10 μm from the surface, is observed in FIG. 3 and is irradiated with unit pulse light. This is a region where a phenomenon such as alteration or scattering removal has occurred directly (hereinafter referred to as a direct alteration region). Then, an area observed between the directly altered regions, which is observed such that a number of streak portions having a longitudinal direction in the left-right direction as viewed in the drawing are connected at a submicron pitch in the up-down direction as viewed in the drawing, is cleaved / dehised. Surface. Below these directly altered regions and cleavage / cleavage surfaces are the divided surfaces formed by the division.

  Since the region where the cleavage / cleavage surface is formed is not a region irradiated with laser light, only the directly altered region formed discretely becomes a processing mark in the processing according to the first processing pattern. ing. And the size in the to-be-processed surface of a direct alteration region is only about several hundred nm-1 micrometer. That is, by performing the processing with the first processing pattern, it is possible to realize the formation of the division starting point in which the formation of the processing marks is suitably suppressed as compared with the conventional case.

  In addition, what is actually observed as a streak portion in the SEM image is a minute unevenness having a height difference of about 0.1 μm to 1 μm formed on the cleavage / dehiscence surface. Such unevenness is caused by a strong impact or stress acting on the work piece by irradiation of unit pulse light when cleaving / cleaving a hard brittle inorganic compound such as sapphire. It is formed by sliding.

  Although such fine irregularities exist, from FIG. 3 it is judged that the surface and the cross section are almost orthogonal with respect to the wavy line as a boundary, so that the fine irregularities are allowed as a processing error. It can be said that the workpiece can be divided substantially perpendicularly to the surface thereof by forming the dividing starting point by the first processing pattern and dividing the workpiece along the dividing starting point.

  As will be described later, it may be preferable to positively form such fine irregularities. For example, the effect of improving the light extraction efficiency that is remarkably obtained by the processing by the second processing pattern described below may be exhibited to some extent by the processing by the first processing pattern.

<Second processing pattern>
The second processing pattern is an aspect of cleavage / dehiscence processing when any of the a1 axis direction, the a2 axis direction, and the a3 axis direction is perpendicular to the processing planned line. In addition, the conditions of the laser beam used in a 2nd process pattern are the same as that of a 1st process pattern. More generally speaking, machining in the case where the direction equivalent to two different cleavage / cleavage directions (the direction of the symmetry axis of the two cleavage / cleavage easy directions) is the direction of the planned machining line. It is an aspect.

  FIG. 4 is a diagram schematically showing a processing mode by the second processing pattern. FIG. 4 illustrates a case where the a1 axis direction and the planned machining line L are orthogonal to each other. FIG. 4A is a diagram illustrating an azimuth relationship between the a1 axis direction, the a2 axis direction, the a3 axis direction, and the planned machining line L in such a case. FIG. 4B shows a state in which the unit pulse light of the first pulse of the laser light is irradiated to the irradiated region RE11 at the end of the processing line L.

  Also in the case of the second processing pattern, the weak intensity portion is formed by irradiating the unit pulse light of the ultrashort pulse, similarly to the first processing pattern. In FIG. 4B, among the weak strength portions formed in each of the above cleavage / cleavage easy directions, the weak strength portions W11a and W12a in the −a2 direction and the + a3 direction close to the extending direction of the processing line L are shown. This is schematically indicated by a broken arrow.

Then, as shown in FIG. 4 (c), are irradiated laser light second unit pulsed beam of the irradiated region at a position from the irradiated region RE 11 separated by a predetermined distance on the planned processing line L RE When 12 is formed, similarly to the first pulse, a weak intensity portion along the easy cleavage / dehiscence direction is also formed in the second pulse. For example, a weak strength portion W11b is formed in the -a3 direction, a weak strength portion W12b is formed in the + a2 direction, a weak strength portion W11c is formed in the + a3 direction, and a weak strength portion W12c is formed in the -a2 direction. Will be.

  Also in this case, as in the case of the first processing pattern, the weak intensity portions W11a and W12a formed by the irradiation of the first unit pulse light are present in the extending direction of the weak intensity portions W11b and W12b, respectively. Actually, when the unit pulse light of the second pulse is irradiated, the impact or stress generated at that time propagates to the easy-cleavage / cleavage direction and the weak intensity portion existing ahead. That is, as shown in FIG. 4D, cleavage / cleavage surfaces C11a and C11b are formed. Also in this case, the cleavage / cleavage surfaces C11a and C11b can be formed to a depth of about several μm to several tens of μm in the direction perpendicular to the drawing of the workpiece.

  Subsequently, as shown in FIG. 4E, when the laser beam is scanned along the planned processing line L and the irradiated regions RE11, RE12, RE13, RE14,. The cleaved / cleavage surfaces C11a and C11b, C12a and C12b, C13a and C13b, C14a and C14b. It will be formed.

  As a result, a state in which the cleavage / cleavage plane is positioned symmetrically with respect to the planned processing line L is realized. In the second machining pattern, the plurality of irradiated areas discretely present along the planned machining line L and the cleavage / cleavage surfaces present in a zigzag form as a whole are intended to process the workpiece. It becomes a division starting point when dividing along L.

  FIG. 5 is an optical microscope image of the surface of the workpiece on which the division starting points are formed by the cleavage / cleavage processing in the second processing pattern. Specifically, the sapphire C-plane substrate is a workpiece, and the irradiated spots are discretely spaced at intervals of 7 μm on the C-plane with the direction orthogonal to the a1 axis direction as the extending direction of the processing line L. The result of processing to be formed is shown. From FIG. 5, even in an actual workpiece, a zigzag (zigzag) cleavage / cleavage surface is observed in the same manner as that schematically shown in FIG. 4 (e). Such a result suggests that the actual workpiece is processed by the mechanism described above.

  FIG. 6 is an SEM image from the surface (c-plane) to the cross-section after dividing the sapphire C-plane substrate on which the division starting points are formed by processing according to the second processing pattern along the division starting points. In FIG. 6, the boundary between the surface and the cross section is indicated by a broken line.

  From FIG. 6, in the range of about 10 μm from the surface of the cross section of the workpiece after division, the cross section of the workpiece has irregularities corresponding to the staggered arrangement schematically shown in FIG. It is confirmed that it has. It is the cleavage / cleavage surface that forms such irregularities. In addition, the uneven | corrugated pitch in FIG. 6 is about 5 micrometers. As in the case of the processing by the first processing pattern, the cleavage / cleavage surface is not flat, and unevenness of a submicron pitch is generated due to slippage on a specific crystal plane due to irradiation of unit pulse light. Yes.

  Further, it is the cross section of the directly altered region that extends from the surface portion in the depth direction corresponding to the position of the convex and concave portions. Compared to the directly altered region formed by the processing by the first processing pattern shown in FIG. 3, the shape is non-uniform. Further, below the direct alteration region and the cleavage / cleavage surface is a divided surface formed by the division.

  The second machining pattern is the same as the first machining pattern in that only the directly altered region formed discretely is a machining trace. And the size in the to-be-processed surface of a direct alteration area | region is only about several hundred nm-2 micrometers. That is, even when processing with the second processing pattern is performed, formation of the division starting point in which the formation of the processing trace is more suitable than the conventional one is realized.

In the case of processing by the second processing pattern, in addition to the submicron pitch unevenness formed on the cleavage / cleavage surface, the adjacent cleavage / cleavage surfaces form unevenness with a pitch of about several μm. In a mode of forming a cross-section having such a concavo-convex shape, a work piece in which a light-emitting element structure such as an LED structure is formed on a substrate made of a hard and brittle and optically transparent material such as sapphire is chip (divided). This is effective when dividing into units. In the case of a light-emitting element, if the light generated inside the light-emitting element is absorbed at the location of the processing mark formed on the substrate by laser processing, the light extraction efficiency from the element will be reduced, When the unevenness as shown in FIG. 6 is intentionally formed on the processed cross section of the substrate by performing the processing with the second processing pattern, the total reflectance at the position is lowered and higher in the light emitting element. Light extraction efficiency will be realized.

<Third processing pattern>
In the third processing pattern, a point using an ultra-short pulse laser beam, a1 axis direction, a2 axis direction, or a3 axis direction is perpendicular to the planned processing line (in two different cleavage / cleavage easy directions). On the other hand, in the point that the equivalent direction is the direction of the planned processing line), the laser beam irradiation mode is different from that of the second processing pattern.

  FIG. 7 is a diagram schematically showing a processing mode by the third processing pattern. FIG. 7 illustrates a case where the a1 axis direction and the planned machining line L are orthogonal to each other. FIG. 7A is a diagram illustrating an azimuth relationship between the a1 axis direction, the a2 axis direction, the a3 axis direction, and the planned processing line L in such a case.

  In the second machining pattern described above, the laser beam is exactly in the middle of the a2 axis direction and the a3 axis direction, which are the extending directions of the planned machining line L, under the same orientation relationship as that shown in FIG. Along the direction (equivalent to the a2 axis direction and the a3 axis direction). In the third machining pattern, instead of this, as shown in FIG. 7B, the individual irradiated regions are staggered in an aspect along the two easy cleavage / cleavage directions sandwiching the machining line L. The unit pulse light for forming each irradiated region is irradiated so as to be formed in a zigzag manner. In the case of FIG. 7, irradiated regions RE21, RE22, RE23, RE24, RE25... Are formed along the −a2 direction and the + a3 direction alternately.

  Even when the unit pulse light is irradiated in such a manner, a cleavage / cleavage surface is formed between the irradiated regions as each unit pulse light is irradiated, as in the first and second processing patterns. The In the case shown in FIG. 7 (b), the irradiated regions RE21, RE22, RE23, RE24, RE25,... Are formed in this order, so that the cleavage / cleavage surfaces C21, C22, C23, C24,. -Are formed sequentially.

  As a result, in the third processing pattern, a plurality of irradiated areas discretely present in a staggered arrangement with the planned processing line L as an axis, and a cleavage / crack formed between each irradiated area The open surface as a whole becomes a division starting point when the workpiece is divided along the planned machining line L.

  Then, when the division is actually performed along the division starting point, in the range of about 10 μm from the surface of the cross section of the workpiece after the division, the cleavage / dehissing surface is used as in the second machining pattern. Unevenness with a pitch of several μm is formed. In addition, as in the case of the first and second processing patterns, each cleaved / cleavage surface has a submicron pitch due to the occurrence of slippage on a specific crystal plane due to irradiation of unit pulse light. Unevenness occurs. In addition, the directly altered region is formed in the same manner as the second processing pattern. That is, in the third processing pattern, the formation of the processing trace is suppressed to the same extent as the second processing pattern.

  Therefore, in the case of processing by such a third processing pattern, in addition to the submicron pitch irregularities formed on the cleavage / cleavage surfaces, in the same way as the processing by the second pattern, several μm by the cleavage / cleavage surfaces. Since unevenness of a certain pitch is formed, even when the processing by the third processing pattern is performed on the light emitting element, the obtained light emitting element is from the viewpoint of improving the light extraction efficiency as described above. It becomes more suitable.

  Note that, depending on the type of workpiece, in order to cause cleavage / dehiscence more reliably, both of the irradiated region RE21 and irradiated region RE22 in FIG. The midpoint, the midpoint of the irradiated region RE22 and the irradiated region RE23, the midpoint of the irradiated region RE23 and the irradiated region RE24, the midpoint of the irradiated region RE24 and the irradiated region RE25,. A region may be formed.

  By the way, the arrangement position of the irradiated region in the third processing pattern is partially along the easy cleavage / cleavage direction. The same applies to the case where the irradiated region is also formed at the midpoint position on the planned processing line L as described above. That is, it can also be said that the third processing pattern is common to the first processing pattern in that at least two irradiated areas are formed adjacent to each other in the cleavage / cleavage easy direction of the workpiece. Accordingly, from a different perspective, the third processing pattern can be regarded as a processing performed by the first processing pattern while periodically changing the laser beam scanning direction.

  In the case of the first and second processing patterns, since the irradiated region is positioned on a straight line, the laser light emission source is moved along the planned processing line to reach a predetermined formation target position. What is necessary is just to form a to-be-irradiated area | region by irradiating unit pulse light every time, and the formation aspect which concerns is the most efficient. However, in the case of the third processing pattern, the irradiated area is formed not in a straight line but in a zigzag pattern (in a zigzag pattern), so that not only a method of actually moving the laser beam emission source in a zigzag pattern (in a zigzag pattern). The irradiated region can be formed by various methods. In the present embodiment, the movement of the emission source means a relative movement between the workpiece and the emission source, and not only when the workpiece is fixed and the emission source moves, but also the emission source. Is fixed and the workpiece moves (actually, the stage on which the workpiece is placed moves).

  For example, as described above, by periodically moving the emission direction of the laser beam in a plane perpendicular to the planned processing line while relatively moving the output source and the stage at a constant speed parallel to the planned processing line. It is also possible to form the irradiated region in a manner that satisfies a staggered arrangement relationship.

  Alternatively, the above-described staggered arrangement relationship is achieved by periodically changing the irradiation timing of the unit pulse light from each emission source while relatively moving the plurality of emission sources at a constant speed in parallel. It is also possible to form an irradiated region with

  FIG. 8 is a diagram showing the relationship between the planned processing line and the planned formation position of the irradiated region in these two cases. In any case, as shown in FIG. 8, the formation planned positions P21, P22, P23, P24, P25... Of the irradiated regions RE21, RE22, RE23, RE24, RE25. .. Are alternately set on the parallel straight lines Lα and Lβ, and the formation of irradiated regions at the planned formation positions P21, P23, P25... Along the straight line Lα and the planned formation positions P22 and P24 along the straight line Lβ. · · · · · · · · · · · · · · · · · · ·

  When the emission source is moved in a zigzag manner (zigzag), the laser beam is relatively scanned by moving the stage on which the workpiece is placed, even if the emission source of the laser beam is directly moved. In any case, the movement of the emission source or stage is a two-axis simultaneous operation. On the other hand, the operation of moving only the emission source or the stage in parallel with the planned processing line is a uniaxial operation. Therefore, it can be said that the latter is more suitable for realizing high-speed movement of the emission source, that is, improvement of processing efficiency.

  As shown in each of the above processing patterns, the cleavage / cleavage processing performed in the present embodiment causes discrete irradiation of unit pulse light to cause continuous cleavage / cleavage mainly in the workpiece. This is a processing mode used as a means for imparting impact and stress. Deterioration (that is, formation of machining traces) and scattering of the workpiece in the irradiated area are only locally generated as incidental. The cleavage / cleavage processing of the present embodiment having such characteristics performs processing by causing alteration / melting / evaporation removal continuously or intermittently while overlapping irradiation regions of unit pulse light. The mechanism is essentially different from the conventional processing method.

  Further, since it is sufficient that a strong impact or stress is instantaneously applied to each irradiated region, it is possible to irradiate while scanning with laser light at a high speed. Specifically, extremely high-speed scanning, that is, high-speed machining at a maximum of 1000 mm / sec can be realized. Considering that the processing speed in the conventional processing method is about 200 mm / sec at most, the difference is remarkable. Naturally, it can be said that the processing method realized in the present embodiment improves the productivity at each stage as compared with the conventional processing method.

  In the cleavage / cleavage processing in the present embodiment, the crystal orientation of the workpiece (the orientation in the cleavage / easy cleavage direction) and the planned processing line are in a predetermined relationship as in each of the above-described processing patterns. However, the object of application is not limited to these. In principle, the present invention can also be applied to a case where the two are in an arbitrary relationship and the workpiece is a polycrystalline body. In these cases, the direction in which cleavage / cleavage occurs with respect to the planned processing line is not always constant, and irregular irregularities may occur at the division starting point. However, the laser light including the interval between the irradiated areas and the pulse width may be used. By appropriately setting the irradiation conditions, it is possible to perform processing without any practical problems in which the unevenness remains within the allowable range of processing errors.

<Overview of laser processing equipment>
Next, a laser processing apparatus capable of realizing the above-described various processing patterns will be described.

  FIG. 9 is a schematic diagram schematically showing the configuration of the laser processing apparatus 50 according to the present embodiment. The laser processing device 50 includes a laser beam irradiation unit 50A, an observation unit 50B, a transparent member such as quartz, a stage 7 on which the workpiece 10 is placed, and various laser processing devices 50. The controller 1 mainly controls operations (observation operation, alignment operation, processing operation, etc.). The laser light irradiation unit 50A includes the laser light source SL and the optical system 5, and is a part that irradiates the workpiece 10 placed on the stage 7 with laser light, and corresponds to the laser light emission source described above. . The observation unit 50B includes surface observation for directly observing the workpiece 10 from a side irradiated with laser light (referred to as a surface or a workpiece surface), and a side placed on the stage 7 (referred to as a back surface). Alternatively, it is a part that performs backside observation that is observed through the stage 7.

  The stage 7 is movable in the horizontal direction between the laser beam irradiation unit 50A and the observation unit 50B by the moving mechanism 7m. The moving mechanism 7m moves the stage 7 in a predetermined XY 2-axis direction within a horizontal plane by the action of a driving unit (not shown). Thereby, the movement of the laser beam irradiation position in the laser beam irradiation unit 50A, the movement of the observation position in the observation unit 50B, the movement of the stage 7 between the laser beam irradiation unit 50A and the observation unit 50B, and the like are realized. It becomes. As for the moving mechanism 7m, a rotation (θ rotation) operation in a horizontal plane around a predetermined rotation axis can be performed independently of horizontal driving.

  In the laser processing apparatus 50, the front surface observation and the back surface observation can be switched appropriately. Thereby, the optimal observation according to the material and state of the workpiece 10 can be performed flexibly and promptly.

  The stage 7 is formed of a transparent member such as quartz, and a suction pipe (not shown) serving as an intake passage for adsorbing and fixing the workpiece 10 is provided therein. The suction pipe is provided, for example, by drilling a predetermined position of the stage 7 by machining.

  With the workpiece 10 placed on the stage 7, suction is performed on the suction pipe by the suction means 11 such as a suction pump, for example, and the suction provided at the stage 7 mounting surface side tip of the suction pipe. The workpiece 10 (and the fixing sheet 4) is fixed to the stage 7 by applying a negative pressure to the holes. FIG. 9 illustrates the case where the workpiece 10 to be processed is attached to the fixed sheet 4. Preferably, the fixed sheet 4 is fixed to the outer edge portion of the fixed sheet 4. A fixing ring (not shown) is provided.

  Although not shown in FIG. 9, the laser beam irradiation unit 50 </ b> A is provided with a cooling mechanism 60 (see FIG. 12) below the stage 7. The laser processing apparatus 50 according to the present embodiment is characteristic in that the cooling mechanism 60 is provided. Details of the cooling mechanism 60 will be described later.

<Illumination system and observation system>
The observation unit 50B irradiates the workpiece 10 placed on the stage 7 with the epi-illumination light L1 from the epi-illumination light source S1 from above the stage 7 and the oblique light-transmitting illumination light L2 from the oblique illumination light source S2. The surface observation by the surface observation means 6 from above the stage 7 and the back surface observation by the back surface observation means 16 from below the stage 7 can be performed.

  Specifically, the epi-illumination light L1 emitted from the epi-illumination light source S1 is reflected by the half mirror 9 provided in a lens barrel (not shown) and is irradiated onto the workpiece 10. . The observation unit 50B includes surface observation means 6 including a CCD camera 6a provided above the half mirror 9 (above the lens barrel) and a monitor 6b connected to the CCD camera 6a. The bright field image of the workpiece 10 can be observed in real time with the light L1 irradiated.

  In the observation unit 50B, a CCD camera 16a provided below the stage 7, more preferably below a half mirror 19 described later (below the lens barrel), and a monitor 16b connected to the CCD camera 16a, The back surface observation means 16 containing is provided. The monitor 16b and the monitor 6b provided in the surface observation means 6 may be common.

  Further, the coaxial illumination light L3 emitted from the coaxial illumination light source S3 provided below the stage 7 is reflected by the half mirror 19 provided in a lens barrel (not shown) and collected by the condenser lens 18. In addition, the workpiece 10 may be irradiated via the stage 7. More preferably, an oblique illumination light source S4 may be provided below the stage 7 so that the oblique illumination light L4 can be applied to the workpiece 10 via the stage 7. These coaxial illumination light source S3 and oblique illumination light source S4 are, for example, when there is an opaque metal layer on the surface side of the workpiece 10 and it is difficult to observe from the surface side due to reflection from the metal layer. It can be suitably used when observing the workpiece 10 from the back side.

<Laser light source>
As the laser light source SL, one having a wavelength of 500 nm to 1600 nm is used. Further, in order to realize the processing with the processing pattern described above, the pulse width of the laser beam LB needs to be about 1 psec to 50 psec. The repetition frequency R is preferably about 10 kHz to 200 kHz, and the laser beam irradiation energy (pulse energy) is preferably about 0.1 μJ to 50 μJ.

  The polarization state of the laser beam LB emitted from the laser light source SL may be circularly polarized light or linearly polarized light. However, in the case of linearly polarized light, for example, the angle between the two is within ± 1 ° so that the polarization direction is substantially parallel to the scanning direction from the viewpoint of the bending of the processed cross section in the crystalline work material and the energy absorption rate. It is preferable that it is made to exist.

<Optical system>
The optical system 5 is a part that sets an optical path when the workpiece 10 is irradiated with laser light. In accordance with the optical path set by the optical system 5, laser light is irradiated to a predetermined irradiation position of the workpiece (formation position of the irradiation area).

  FIG. 10 is a schematic view illustrating the configuration of the optical system 5. The optical system 5 mainly includes a beam expander 51 and an objective lens system 52. The optical system 5 may be provided with an appropriate number of mirrors 5a at appropriate positions for the purpose of changing the direction of the optical path of the laser beam LB. FIG. 10 illustrates a case where two mirrors 5a are provided.

  Further, when the emitted light is linearly polarized light, the optical system 5 preferably includes an attenuator 5b. The attenuator 5b is disposed at an appropriate position on the optical path of the laser beam LB, and plays a role of adjusting the intensity of the emitted laser beam LB.

  In the optical system 5 illustrated in FIG. 10, the laser light LB emitted from the laser light source SL is provided so as to irradiate the workpiece 10 with its optical path fixed during the processing. Yes. In addition to this, a plurality of optical paths of the laser light LB when the laser light LB emitted from the laser light source SL is irradiated onto the workpiece 10 are actually or virtually set, and the optical path setting means 5c ( According to FIG. 11, the optical path when the individual unit pulse light of the laser light LB is irradiated onto the workpiece may be configured to be sequentially switched among the plurality of set optical paths. . In the latter case, a state where simultaneous scanning is performed at a plurality of locations on the upper surface of the workpiece 10 or a state virtually regarded as such is realized. In other words, it can be said that the optical path of the laser beam LB is multiplied.

  Although FIG. 9 illustrates a case where scanning is performed at three positions with the three laser beams LB0, LB1, and LB2, the manner of multiplexing the optical path by the optical system 5 is not necessarily limited to this. A specific configuration example of the optical system 5 will be described later.

<Controller>
The controller 1 controls the operation of each of the above-described units, and implements a control unit 2 that realizes processing of the workpiece 10 in various modes to be described later, a program 3p that controls the operation of the laser processing apparatus 50, and processing processing. It further includes a storage unit 3 for storing various data referred to at the time.

  The control unit 2 is realized by a general-purpose computer such as a personal computer or a microcomputer, for example, and various components can be obtained by reading and executing the program 3p stored in the storage unit 3 into the computer. Is realized as a functional component of the control unit 2.

  Specifically, the control unit 2 includes a drive control unit 21 that controls operations of various driving parts related to processing such as driving of the stage 7 by the moving mechanism 7m and focusing operation of the condenser lens 18, CCD, The imaging control unit 22 that controls imaging by the cameras 6a and 16a, the irradiation control unit 23 that controls the irradiation of the laser light LB from the laser light source SL and the setting of the optical path in the optical system 5, and the stage 7 by the suction means 11 A suction control unit 24 for controlling the suction fixing operation of the workpiece 10 and a processing for executing a processing to the processing target position in accordance with the given processing position data D1 (described later) and processing mode setting data D2 (described later). The unit 25 is mainly provided.

  The storage unit 3 is realized by a storage medium such as a ROM, a RAM, and a hard disk. The storage unit 3 may be implemented by a computer component that implements the control unit 2, or may be provided separately from the computer, such as a hard disk.

  In the storage unit 3, machining position data D1 describing the position of the planned machining line set for the workpiece 10 is given from the outside and stored. The storage unit 3 describes conditions for individual parameters of the laser beam, optical path setting conditions in the optical system 5, driving conditions for the stage 7 (or their settable ranges), and the like for each processing mode. Processing mode setting data D2 is stored in advance.

  Various input instructions given by the operator to the laser processing apparatus 50 are preferably performed using a GUI realized in the controller 1. For example, a processing menu is provided on the GUI by the operation of the processing unit 25. Based on the processing menu, the operator selects a processing mode, which will be described later, and inputs processing conditions.

<Alignment operation>
In the laser processing apparatus 50, prior to the processing, the observation unit 50B can perform an alignment operation for finely adjusting the arrangement position of the workpiece 10. The alignment operation is a process performed to make the XY coordinate axes defined on the workpiece 10 coincide with the coordinate axes of the stage 7. Such alignment processing is performed when the processing with the above-described processing pattern is performed so that the crystal orientation of the workpiece, the planned processing line, and the scanning direction of the laser light satisfy a predetermined relationship required in each processing pattern. Is important.

  The alignment operation can be performed by applying a known technique, and may be performed in an appropriate manner according to the processing pattern. For example, in the case where a repeated pattern is formed on the surface of the workpiece 10 such as when a large number of device chips manufactured using one mother substrate are cut out, a method such as pattern matching is used. Thus, an appropriate alignment operation is realized. In this case, roughly speaking, the CCD camera 6a or 16a acquires captured images of a plurality of alignment marks formed on the workpiece 10, and based on the relative relationship between the captured positions of these captured images. The processing unit 25 specifies the alignment amount, and the drive control unit 21 moves the stage 7 by the moving mechanism 7m according to the alignment amount, thereby realizing alignment.

  By performing such an alignment operation, the machining position in the machining process is accurately specified. Note that after the alignment operation is completed, the stage 7 on which the workpiece 10 is placed moves to the laser beam irradiation unit 50A, and subsequently a processing process is performed by irradiating the laser beam LB. The movement of the stage 7 from the observation unit 50B to the laser beam irradiation unit 50A is guaranteed so that the planned processing position assumed during the alignment operation does not deviate from the actual processing position.

<Outline of processing>
Next, the processing in the laser processing apparatus 50 according to the present embodiment will be described. In the laser processing apparatus 50, the laser beam LB emitted from the laser light source SL and passed through the optical system 5 is combined with the movement of the stage 7 on which the workpiece 10 is placed and fixed, thereby passing through the optical system 5. The workpiece 10 can be processed while the laser beam is scanned relative to the workpiece 10.

  The laser processing apparatus 50 is characterized in that a basic mode and a multi mode can be alternatively selected as a processing mode (processing mode) by scanning (relatively) the laser beam LB. Is. These processing modes are provided according to the setting mode of the optical path in the optical system 5 described above.

  The basic mode is a mode in which the optical path of the laser beam LB emitted from the laser light source SL is fixedly determined. In the basic mode, the laser beam LB always passes through one optical path, and the stage 7 on which the workpiece 10 is placed is moved at a predetermined speed so that the laser beam scans the workpiece 10 in one direction. Is realized. In the case of the optical system 5 illustrated in FIG. 10, only processing in the basic mode is possible.

  The basic mode is preferably used when performing processing with the above-described first and second processing patterns. That is, for the workpiece 10 in which the planned processing line L is set parallel to the cleavage / easy cleavage direction, the workpiece 10 is aligned so that the cleavage / easy cleavage direction coincides with the moving direction of the stage 7. In addition, the first processing pattern can be processed by processing in the basic mode. On the other hand, with respect to the workpiece 10 in which the planned processing line L is set to be perpendicular to the cleavage / easy cleavage direction, the workpiece 10 is aligned so that the cleavage / easy cleavage direction and the moving direction of the stage 7 are orthogonal to each other. In addition, the second processing pattern can be processed by performing processing in the basic mode.

  Further, in principle, it can also be applied to machining with the third machining pattern by appropriately changing the moving direction of the stage 7.

  On the other hand, the multi mode is a mode in which a plurality of optical paths are set by actually or virtually multiplexing the optical path of the laser beam LB. For example, as shown in FIG. 8, a plurality of laser beams are scanned substantially or virtually along the straight lines Lα and Lβ parallel to the planned processing line L or further along the planned processing line L itself. As a result, this is a mode that realizes the same processing as when the laser beam is scanned in a manner that repeatedly intersects the planned processing line L. Note that virtually scanning a plurality of laser beams is actually irradiating a laser beam with one optical path as in the basic mode, but by changing the optical path with time, It means that the same scanning mode as that in the case of irradiating with laser light is realized.

  The multi mode is suitably used when processing with the third processing pattern. That is, as in the case of the second machining pattern, for the workpiece 10 in which the planned machining line L is set to be perpendicular to the cleavage / easy cleavage direction, the cleavage / easy cleavage direction and the moving direction of the stage 7 are the same. After the workpiece 10 is aligned so as to be orthogonal to each other, the third processing pattern can be processed by performing processing in a multimode.

Processing mode, for example, it is preferable that the processing menu thus selected to be provided available to the operator in the controller 1 by the action of the processing unit 25. The processing unit 25 acquires the processing position data D1 and the conditions corresponding to the selected processing pattern from the processing mode setting data D2, and the drive control unit 21 or the like so that the operation according to the conditions is executed. The operation of each corresponding unit is controlled through the irradiation control unit 23 and others.

  For example, adjustment of the wavelength and output of the laser light LB emitted from the laser light source SL, the pulse repetition frequency, the pulse width, and the like are realized by the irradiation control unit 23 of the controller 1. When a predetermined setting signal according to the processing mode setting data D2 is issued from the processing unit 25 to the irradiation control unit 23, the irradiation control unit 23 sets the irradiation condition of the laser beam LB according to the setting signal.

  In particular, when processing is performed in the multimode, the irradiation controller 23 synchronizes the timing of switching the optical path by the optical path setting means 5c with the timing of emitting the unit pulse light from the laser light source SL. Thereby, unit pulse light is irradiated with respect to the planned formation position of each irradiation region in the optical path corresponding to the planned formation position among the plurality of optical paths set by the optical path setting means 5c.

  In the laser processing apparatus 50, it is possible to irradiate the laser beam LB in the defocus state in which the in-focus position is intentionally shifted from the surface of the workpiece 10 as necessary during the processing. It has become. This is realized, for example, by adjusting the relative distance between the stage 7 and the optical system 5.

<Configuration example and operation of optical path setting means>
Next, a specific configuration of the optical path setting unit 5c and an example of the operation will be described mainly for the operation in the multimode.

  In the following description, the processing is performed while moving the stage 7 on which the workpiece 10 is placed along the moving direction D that coincides with the extending direction of the processing line L. To do.

  Further, in the multi-mode operation, the laser beam LB0 is irradiated when the irradiated region RE is formed on the planned processing line L, and the irradiated region on the straight line Lα parallel to the planned processing line L. The laser beam LB1 is irradiated when the RE is formed. The laser beam LB1 is also irradiated when the irradiated region RE is formed on the straight line Lβ parallel to the processing line L and symmetrical with respect to the processing line L. Is the laser beam LB2.

  Further, the processing of the third processing pattern in the multi-mode is realized by positioning a plurality of irradiated regions formed sequentially or simultaneously along the easy cleavage / cleavage direction.

  FIG. 11 is a diagram schematically showing the configuration of the optical path setting means 5c. The optical path setting means 5 c is provided as a component of the optical system 5. The optical path setting unit 5 c includes a plurality of half mirrors 53, a mirror 54, and an optical path selection mechanism 55.

  The half mirror 53 and the mirror 54 divide the optical path of the laser beam LB emitted from the laser light source SL in an in-plane direction perpendicular to the moving direction D of the stage 7, and a plurality of optical paths (laser beams LB0, LB1, and LB2). Provided to form an optical path). The number of half mirrors 53 is determined according to the number of optical paths. In FIG. 11, two half mirrors 53 are provided to obtain three optical paths. By providing the half mirror 53 and the mirror 54, the stage 7 is moved while emitting the laser beam LB, thereby realizing a state in which a plurality of laser beams scan the workpiece 10.

  The optical path selection mechanism 55 is provided to control the emission timing of the laser light to the workpiece 10 in a plurality of optical paths. More specifically, the optical path selection mechanism 55 includes an optical switch SW in the middle of the optical path of each laser beam branched by the half mirror 53 and the mirror 54. The optical switch SW is composed of, for example, an AOM (acousto-optic modulator) or an EOM (electro-optic device), and allows the incident laser light to pass when it is in the ON state, and blocks or attenuates the incident laser light when it is in the OFF state. It has a function to make it (non-passing state). Thereby, in the optical path selection mechanism 55, only the laser beam that passes through the optical switch SW in the ON state is irradiated to the workpiece 10.

  In the multi-mode operation of the laser processing apparatus 50 including the optical path setting means 5c having such a configuration, the irradiation control unit 23 performs the laser light LB0 according to the emission timing of the unit pulse light of the laser light LB according to the repetition frequency R. This is realized by controlling the ON / OFF operation of each optical switch SW so that the optical switches SW on the optical paths of LB1, LB2 are sequentially and periodically turned on. By such control, the laser beam LB0, LB1, LB2 passes through the optical path selection mechanism 55 and is irradiated on the workpiece 10 only when the timings at which the laser beams LB0, LB1, LB2 form the irradiated region are reached. It will be.

  That is, a plurality of optical paths of laser light irradiated to the workpiece 10 are actually provided, and by scanning the plurality of laser lights simultaneously in parallel while changing the irradiation timing of each unit pulse light, Multi-mode operation is performed.

  Note that the operation in the basic mode is possible, for example, by moving only the optical switch SW on any one of the optical paths of the laser beams LB0, LB1, and LB2 to emit the laser beam LB and moving the stage 7. It is.

<Cooling of workpiece and high efficiency of cleavage / cleavage>
The above-described cleavage / cleavage processing is a technique for causing cleavage / cleavage in a workpiece using an impact or stress generated by irradiation with unit pulse light. Therefore, the cleavage / cleavage plane is formed with less energy consumption when irradiated with individual unit pulse light, so that the cleaving / cleavage is deeper in the workpiece even if the applied energy is the same. As a result, the tip of the split starting point reaches a deeper part of the workpiece, and the cleavage / cleavage surface is more efficiently formed.

  Based on the above viewpoints, in this embodiment, more efficient cleavage / dehiscence processing is realized by irradiating a pulse laser beam in a state in which tensile stress is applied to the processing surface in advance. So that Specifically, a temperature difference is generated between the mounting surface and the processing surface by cooling the mounting surface of the workpiece. When such a temperature difference occurs, in the work piece, the placement surface side becomes more contracted than the work surface side, and as a result, tensile stress acts on the work surface side. become. If pulse laser light is irradiated in this state, the energy consumed in forming the cleavage / cleavage surface is reduced by the amount of the tensile stress acting, and as a result, the cleavage / cleavage surface is likely to progress. Become.

  In general, the fracture toughness value of a solid decreases as the temperature decreases. And as the fracture toughness value is lower, the cleavage / cleavage surface is more easily formed. Therefore, by cooling the mounting surface in the above-described manner, the workpiece has a state in which the fracture toughness value is lower toward the mounting surface side, that is, a state in which the cleavage / cleavage surface is more likely to progress. Yes. Cooling the work surface of the work piece also contributes to higher efficiency of the cleavage / dehissing process from this point.

  That is, in the present embodiment, by cooling the work surface of the work piece, two events of applying tensile stress to the work surface and lowering the fracture toughness value on the work surface side are caused simultaneously. In this state, the cleavage / cleavage process is performed, so that the cleavage / cleavage surface can be formed more efficiently.

<Cooling mechanism>
Next, in the laser processing apparatus 50, the cooling mechanism 60 responsible for cooling the workpiece from the mounting surface side will be described. FIG. 12 is a diagram illustrating the configuration and arrangement position of the cooling mechanism 60. FIG. 12 illustrates a case where the workpiece 10 includes a sapphire substrate 101 and an LED structure 102 formed thereon with a group III nitride or the like.

  As shown in FIG. 12, the cooling mechanism 60 includes a Peltier element 61 that is a cooling member, a support portion 62a that supports the Peltier element 61, and a fin that has a large number of fins. The heat dissipating part 62 including the part 62b, and the fan part 63 that is disposed adjacent to the fin part 62b and blows air to the fin part 62b by driving a fan provided therein.

  The cooling mechanism 60 is configured so that the Peltier element 61 is close to the back surface 7b of the stage 7 opposite to the top surface 7a on which the workpiece 10 is placed when at least the stage 7 is positioned in the laser beam irradiation unit 50A. Is arranged. In such an arrangement state, when the Peltier element 61 is energized by energizing means (not shown), heat absorption occurs on the surface 61a. This heat absorption cools the stage 7 and the placement surface 10a of the workpiece 10 placed thereon. In addition, when the Peltier element 61 absorbs heat on the surface 61a in principle, heat generation on the opposite surface is unavoidable. Therefore, the cooling mechanism 60 has a heat radiating part 62 for releasing the generated heat to the outside, and A fan unit 63 is provided. The cooling mechanism 60 is realized by combining known members.

  When performing the cleavage / dehissing process by irradiating the pulsed laser beam in the laser beam irradiation unit 50A, the cooling mechanism 60 cools the placement surface 10a of the workpiece 10 from the stage 7 side to thereby High efficiency of the cleavage / cleavage processing is realized. The cooling process by the cooling mechanism 60 is preferably controlled by the processing unit 25 integrally with the processing process.

  By the way, what is shown in FIG. 12 is the structure where the stage 7 has the digging part 71 in the center part of the back surface 7b on the opposite side to the upper surface 7a in which the workpiece 10 is mounted. And the cooling mechanism 60 is arrange | positioned so that the Peltier device 61 may adjoin the stage 7 in this digging part 71. FIG. That is, in the stage 7, only the formation part of the digging part 71 is thinner than the other parts. When such a configuration is employed, the placement surface 10 a of the workpiece 10 is more efficiently cooled by the Peltier element 61.

  In this case, at least one of the stage 7 and the cooling mechanism 60 is provided with a moving mechanism in the vertical direction as viewed in the drawing, so as not to interfere with the cooling mechanism 60 when the stage 7 moves to the observation unit 50B.

  Alternatively, a direction perpendicular to the drawing may be a moving direction of the stage 7 by the moving mechanism 7m, and the digging portion 71 may be provided in a manner extending in the direction.

<Modification>
A mode in which a temperature difference is generated between the placement surface and the processing surface is not limited to the above-described embodiment. For example, the same effect can be obtained by heating the surface to be processed instead of cooling the mounting surface.

DESCRIPTION OF SYMBOLS 1 Controller 2 Control part 3 Memory | storage part 4 Fixed sheet 5 Optical system 5c Optical path setting means 7 Stage 7m Movement mechanism 10 Work piece 10a (workpiece's) mounting surface 50 Laser processing apparatus 50A Laser beam irradiation part 51 Beam expander 52 Objective lens system 53 Half mirror 5a, 54 Mirror 55 Optical path selection mechanism 60 Cooling mechanism 61 Peltier element C1-C3, C11a, C11b, C21-C24 Cleavage / cleavage plane D (stage) movement direction L Planned line LB, LB0 , LB1, LB2 Laser light RE, RE1-RE4, RE11-RE15, RE21-RE25 Irradiation area SL Laser light source SW Optical switch

Claims (22)

  1. A light source that emits pulsed laser light;
    A stage on which the workpiece is placed;
    A laser processing apparatus comprising:
    A cooling mechanism for cooling the mounting surface of the workpiece mounted on the stage;
    In the state where the workpiece is placed on the stage and the placement surface is cooled by the cooling mechanism, the irradiated area for each unit pulse light of the pulsed laser light faces the placement surface. So as to be discretely formed on the surface to be processed , and so that at least two irradiated regions formed by different unit pulse lights are adjacent in the direction of easy cleavage or cleavage of the workpiece, By irradiating the workpiece with the pulsed laser light while moving the stage, the workpiece is sequentially cleaved or cleaved between the irradiated regions, thereby causing the workpiece to Form the starting point for the division,
    Laser processing equipment characterized by that.
  2. A light source that emits pulsed laser light;
    A stage on which the workpiece is placed;
    A laser processing apparatus comprising:
    A cooling mechanism for cooling the mounting surface of the workpiece mounted on the stage;
    In a state where the workpiece is placed on the stage and the placement surface is cooled by the cooling mechanism, each unit pulse light of the pulsed laser light is placed on the work surface facing the placement surface. The stage is moved so that it is irradiated in a discrete manner and at least two irradiated areas formed by different unit pulse lights are adjacent in the direction of easy cleavage or cleavage of the workpiece. While irradiating the workpiece with the pulsed laser light, the irradiation position of the unit pulse light irradiated immediately before or simultaneously by the impact or stress when the individual unit pulse light is irradiated to the irradiation position; Forming a starting point for the division in the workpiece by causing cleavage or cleavage during
    Laser processing equipment characterized by that.
  3. The laser processing apparatus according to claim 1 or 2,
    Alternately forming the at least two irradiated regions in two different cleaving or tearing directions of the workpiece;
    Laser processing equipment characterized by that.
  4. The laser processing apparatus according to claim 1 or 2 ,
    Forming all the irradiated areas along the direction of easy cleavage or cleavage of the workpiece;
    Laser processing equipment characterized by that.
  5. A light source that emits pulsed laser light;
    A stage on which the workpiece is placed;
    A laser processing apparatus comprising:
    A cooling mechanism for cooling the mounting surface of the workpiece mounted on the stage;
    In the state where the workpiece is placed on the stage and the placement surface is cooled by the cooling mechanism, the irradiated region for each unit pulse light of the pulse laser light is the workpiece surface on the workpiece surface. By irradiating the workpiece with the pulsed laser light while moving the stage so as to be discretely formed in an equivalent direction with respect to two different cleavage or cleavage easy directions of the workpiece, Forming a starting point for division in the workpiece by sequentially generating cleavage or cleavage of the workpiece between the irradiated regions;
    Laser processing equipment characterized by that.
  6. A light source that emits pulsed laser light;
    A stage on which the workpiece is placed;
    A laser processing apparatus comprising:
    A cooling mechanism for cooling the mounting surface of the workpiece mounted on the stage;
    In a state where the workpiece is placed on the stage and the placement surface is cooled by the cooling mechanism, each unit pulse light of the pulse laser beam is applied to the workpiece on the workpiece surface. The unit laser is irradiated with the pulsed laser light while moving the stage so as to be discretely irradiated in the equivalent direction to two different cleavage or cleavage easy directions. By causing cleavage or cleavage between the irradiation position of the unit pulse light irradiated immediately before or simultaneously due to impact or stress when the irradiation position is irradiated with light, the workpiece is Form the starting point for the division,
    Laser processing equipment characterized by that.
  7. A laser processing apparatus according to any one of claims 1 to 6,
    The pulse laser beam is an ultrashort pulse beam having a pulse width of the order of psec.
    Laser processing equipment characterized by that.
  8. It claims 1 The laser processing apparatus according to claim 7,
    At least at the time of irradiation of the pulse laser beam to the workpiece, the cooling mechanism is disposed below the stage, and the mounting surface is cooled by the cooling mechanism cooling the stage from below.
    Laser processing equipment characterized by that.
  9. It is a laser processing apparatus of Claim 8 , Comprising:
    The cooling mechanism includes a Peltier element;
    At least during the irradiation of the pulsed laser light on the workpiece, the placement surface is cooled by cooling the stage with the Peltier element in a state in which the Peltier element is disposed in proximity to the stage,
    Laser processing equipment characterized by that.
  10. The laser processing apparatus according to claim 8 or 9 , wherein
    A recessed portion is provided on the lower side of the stage, and the cooling mechanism is disposed so as to be close to the stage at the recessed portion.
    Laser processing equipment characterized by that.
  11. A processing method for forming a division starting point on a workpiece,
    A placing step of placing the workpiece on the stage;
    In a state where the mounting surface of the workpiece with respect to the stage is cooled, the pulse laser beam is discretely formed on the processing surface where the irradiation region for each unit pulse light faces the mounting surface. By irradiating the workpiece as described above, the workpiece is sequentially cleaved or cleaved between the irradiated regions, thereby forming a starting point for division in the workpiece. An irradiation process to
    Equipped with a,
    In the irradiation step, at least two irradiated regions formed by the different unit pulse lights are formed so as to be adjacent to each other in the easy cleavage or cleavage direction of the workpiece.
    A processing method of a workpiece characterized by the above.
  12. A processing method for forming a division starting point on a workpiece,
    A placing step of placing the workpiece on the stage;
    In a state where the mounting surface of the workpiece with respect to the stage is cooled, the pulse laser beam is applied so that each unit pulse light is discretely irradiated onto the processing surface facing the mounting surface. Irradiate the workpiece, and cleave or cleave between the irradiated position of the unit pulse light irradiated immediately before or simultaneously with the impact or stress when the irradiated unit pulse light is irradiated to the irradiated position. An irradiation step of forming a starting point for the division on the workpiece,
    Equipped with a,
    In the irradiation step, at least two irradiated regions formed by the different unit pulse lights are formed so as to be adjacent to each other in the easy cleavage or cleavage direction of the workpiece.
    A processing method of a workpiece characterized by the above.
  13. The processing method according to claim 11 or claim 12,
    In the irradiation step, the formation of the at least two irradiated regions is alternately performed in two different cleavage or cleavage easy directions of the workpiece.
    A processing method of a workpiece characterized by the above.
  14. The processing method according to claim 11 or claim 12 ,
    In the irradiation step, all the irradiated region is formed along the direction of easy cleavage or cleavage of the workpiece.
    A processing method of a workpiece characterized by the above.
  15. A processing method according to any one of claims 11 to 13 ,
    In the irradiation step, the pulse laser beam emission source and the workpiece are relatively moved, and the pulse laser beam emission direction is periodically changed in a plane perpendicular to the relative movement direction. To form a plurality of irradiated regions that satisfy a staggered arrangement relationship on the workpiece.
    A processing method of a workpiece characterized by the above.
  16. A processing method according to any one of claims 11 to 13 ,
    In the irradiation step, the irradiation timing of the unit pulse light from each of the plurality of emission sources is periodically changed while relatively moving the plurality of emission sources of the pulse laser light and the workpiece. To form a plurality of irradiated regions that satisfy a staggered arrangement relationship on the workpiece.
    A processing method of a workpiece characterized by the above.
  17. A processing method for forming a division starting point on a workpiece,
    A placing step of placing the workpiece on the stage;
    In a state where the mounting surface of the workpiece with respect to the stage is cooled, the pulse laser beam is discretely formed on the processing surface where the irradiation region for each unit pulse light faces the mounting surface. By irradiating the workpiece as described above, the workpiece is sequentially cleaved or cleaved between the irradiated regions, thereby forming a starting point for division in the workpiece. An irradiation process to
    With
    In the irradiation step, the irradiated region is formed in an equivalent direction with respect to two different cleavage or cleavage easy directions of the workpiece.
    A processing method of a workpiece characterized by the above.
  18. A processing method for forming a division starting point on a workpiece,
    A placing step of placing the workpiece on the stage;
    In a state where the mounting surface of the workpiece with respect to the stage is cooled, the pulse laser beam is applied so that each unit pulse light is discretely irradiated onto the processing surface facing the mounting surface. Irradiate the workpiece, and cleave or cleave between the irradiated position of the unit pulse light irradiated immediately before or simultaneously with the impact or stress when the irradiated unit pulse light is irradiated to the irradiated position. An irradiation step of forming a starting point for the division on the workpiece,
    With
    In the irradiation step, the irradiated region is formed in an equivalent direction with respect to two different cleavage or cleavage easy directions of the workpiece.
    A processing method of a workpiece characterized by the above.
  19. A processing method according to any one of claims 11 to 18 , wherein
    The pulse laser beam is an ultrashort pulse beam having a pulse width of the order of psec.
    A processing method of a workpiece characterized by the above.
  20. A processing method according to any one of claims 11 to 19 , wherein
    In the irradiation step, the cooling mechanism is disposed below the stage, and the stage is cooled by cooling the stage from below by the cooling mechanism,
    A processing method of a workpiece characterized by the above.
  21. The processing method according to claim 20 , wherein
    The cooling mechanism includes a Peltier element;
    In the irradiation step, the placement surface is cooled by cooling the stage with the Peltier element in a state where the Peltier element is disposed in proximity to the stage.
    A processing method of a workpiece characterized by the above.
  22. A method of dividing a workpiece,
    A work piece on which a division starting point is formed by the method according to any one of claims 11 to 21 is divided along the division starting point.
    A workpiece dividing method characterized by the above.
JP2010166229A 2010-07-23 2010-07-23 Laser processing apparatus, workpiece processing method, and workpiece dividing method Expired - Fee Related JP5104919B2 (en)

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KR1020110045004A KR101312427B1 (en) 2010-07-23 2011-05-13 Laser processing apparatus, method of processing products to be processed, and method of dividing products to be processed
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