JP6255147B2 - Cutting device and method for cutting workpiece - Google Patents

Description

  The present invention relates to an apparatus and method for dividing a workpiece by irradiating a laser beam.

  Various methods are known as processing methods for cutting out hard and brittle materials (brittle materials) such as glass plates and sapphire substrates. For example, as processing of a glass plate, so-called scoring is performed in which shallow scratches (initial cracks) are formed with diamond crystals or the like linearly from the edge of the material to be cut, and force is applied to both sides of the formed initial cracks to A method of dividing an initial crack in the thickness direction is widely known.

  However, in the case of such a method, the desired cutting accuracy may occur during the cutting operation, depending on the depth of the scribing and how to apply the force, and the dividing surface may be inclined or cracked in an unexpected direction. In the worst case, there is a risk of damage to the entire material.

  In addition, a method is also widely known in which an initial crack is given to an end portion of a workpiece, and the workpiece is divided by advancing the crack by performing heating scanning with a laser beam from the end portion (for example, , See Patent Document 1).

  In the case of such a method, if the brittle material to be divided is homogeneous and the stress field generated is ideal, the position and direction of crack propagation may be controlled with high precision, but in reality, However, it is difficult to control the crack growth with high accuracy in view of the non-uniformity of the material, the non-uniformity of the heating energy distribution, and the difficulty of high-precision position control of the heating point. Here, high accuracy is assumed to be position control with accuracy on the order of μm.

  Moreover, at the end of the work piece, stress dispersion occurs and the stress distribution is not uniform. For crack growth control, it is necessary to limit the processing procedure or to deliberately shift the heating point (for example, , See Patent Document 2).

  Also, when cutting a brittle material in which unit patterns are two-dimensionally arranged on the surface into pieces (in chip units) for each unit pattern, cutting in two directions orthogonal to each other by laser cleaving After cutting in one direction, cutting is performed in a direction perpendicular thereto, but in the case of a large amount of chip processing, how to give an initial crack becomes more complicated.

  As a combination of the above methods, a minute scratch (initial crack) is provided on the edge of a hard and brittle material substrate (eg glass, silicon, ceramics, sapphire, etc.) with diamond or Vickers indenter, and then laser is applied to the back side of the substrate. A technique is also known in which a light absorbing material is arranged, local heating is performed by laser irradiation focused on the back surface of the substrate, and cracks are developed by stress concentration caused thereby, thereby dividing the glass (see, for example, Patent Document 3). ).

  Alternatively, a linear processing mark called a scribe line or scribe line is mechanically or laser beam irradiated on the surface of the workpiece in advance, and then irradiation heating with laser light is performed along the processing mark. And a method of dividing the workpiece by causing the crack to progress from the processing trace is also known (see, for example, Patent Document 4 and Patent Document 5).

  Note that Patent Document 3 also discloses an aspect in which a laser is irradiated from a surface opposite to the ruled line to perform division.

Japanese Patent Publication No. 3-13040 JP-A-9-45636 JP 2008-62547 A Japanese Patent No. 2712723 Japanese Patent No. 3036906

  In the case of the method disclosed in Patent Document 3, it is only the laser light absorber that is directly heated by the laser light, and the hard and brittle material substrate is indirectly heated by the heat conduction from the laser light absorber. Only. Therefore, it is difficult to ensure the uniformity of heat conduction, and the tensile stress does not always act in the intended direction. Further, like the conventional laser cleaving disclosed in Patent Document 1, it is difficult to control the direction of crack propagation. Therefore, it is difficult to perform accurate division by such a method.

In addition, what is specifically disclosed in Patent Document 4 and Patent Document 5 is an aspect in which a workpiece is divided by irradiating a CO ₂ laser mechanically or along a processing mark formed by laser light. However, a technique for efficiently generating such division is not necessarily disclosed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of dividing a workpiece made of a brittle material with high accuracy and efficiency.

  In order to solve the above-mentioned problems, the invention of claim 1 is an apparatus for performing processing for dividing a workpiece, and a stage for placing and fixing the workpiece, and a first emitted from a first emission source. A scribe line is formed on the scribe surface by irradiating the scribe surface, which is the upper surface of the workpiece placed and fixed on the stage, while scanning the laser beam relative to the stage. By irradiating the second laser light emitted from the processing means and the second emission source and absorbed inside the workpiece along the scribe line while being relatively scanned with respect to the stage. Irradiation heating means for heating the inside of the workpiece along the scribe line, and the irradiation heating means applies the second laser light to the scribe surface. The tensile stress field formed inside the workpiece and in the vicinity of the scribe line is moved by relatively scanning the second laser light along the scribe line, Dividing the workpiece by causing the progress of cracks from the scribe line to the non-scribe surface, which are generated when the scribe line is located in the tensile stress field, sequentially along the scribe line; It is characterized by that.

  A second aspect of the present invention is the cutting apparatus according to the first aspect, wherein the second laser light is either an Er-YAG laser or an Nd-YAG laser.

  A third aspect of the present invention is the cutting apparatus according to the first or second aspect, wherein the irradiation heating means adjusts an irradiation range of the second laser beam emitted from the second emission source. An adjusting mechanism for irradiating the scribe surface with the second laser light whose irradiation range is adjusted by the adjusting mechanism.

  According to a fourth aspect of the invention, there is provided the dividing apparatus according to any one of the first to third aspects, wherein the first laser beam is a third harmonic of a YAG laser.

  A fifth aspect of the present invention is the cutting apparatus according to any one of the first to fourth aspects, wherein the stage is rotatable in a horizontal plane while holding the workpiece, and the stage Alignment processing means for performing alignment processing for correcting the posture of the workpiece placed and fixed on the stage in the horizontal plane by rotating the workpiece in the horizontal plane, and the workpiece subjected to the alignment processing On the other hand, the formation of the scribe line by the scribe processing means and the heating by the irradiation heating means are performed.

  A sixth aspect of the present invention is the cutting apparatus according to any one of the first to fifth aspects, further comprising a cooling fluid supply means for injecting a cooling fluid to the workpiece, and the irradiation heating. The means moves the second laser light by relatively scanning the scribe line while cooling the tensile stress field by jetting the cooling fluid by the cooling fluid supply means. And

  The invention according to claim 7 is a method of dividing a workpiece, wherein the first laser beam is emitted from a first emission source, and the first laser beam is directed to the scribe surface of the workpiece. By irradiating, a scribe process for forming a scribe line on the scribe surface, and a second laser beam absorbed inside the workpiece from a second emission source is emitted, and the second laser beam is emitted. Irradiating from the side of the scribe surface along the scribe line to heat the inside of the workpiece along the scribe line, and in the irradiation heating step, the second The tensile stress field formed in the vicinity of the scribe line inside the workpiece including the scribe surface by the irradiation of the laser beam is applied to the second laser beam. And by moving the scribe line relative to the non-scribe surface, the scribe line causes a crack progress from the scribe line to the non-scribe surface caused by the scribe line being located in the tensile stress field. The workpiece is divided by being sequentially generated along the line.

  The invention of claim 8 is the dividing method according to claim 7, wherein the second laser light is either an Er-YAG laser or an Nd-YAG laser.

  The invention of claim 9 is the dividing method according to claim 7 or claim 8, wherein the irradiation range of the second laser beam emitted from the second emission source is set in the irradiation heating step. The second scribe surface is irradiated with the second laser light after adjustment by an adjustment mechanism.

  A tenth aspect of the invention is the dividing method according to any one of the seventh to ninth aspects, wherein the first laser beam is a third harmonic of a YAG laser.

  The invention of claim 11 is the dividing method according to any one of claims 7 to 10, further comprising an alignment processing step of correcting a posture of the workpiece in a horizontal plane, wherein the alignment processing step The scribe processing step and the irradiation heating step are performed on the workpiece that has been subjected to.

  A twelfth aspect of the invention is the dividing method according to any of the seventh to eleventh aspects, wherein in the scribing step, melting and resolidification occur at the irradiated position of the first laser beam. The scribe line is formed by setting the irradiated position as an altered region.

  Invention of Claim 13 is the dividing method in any one of Claim 7 thru | or 11, Comprising: In the said scribing process, ablation is produced in the irradiated position of said 1st laser beam, The scribe line is formed by forming a groove at the irradiated position.

  A fourteenth aspect of the present invention is the cutting method according to any one of the seventh to twelfth aspects, wherein the irradiation heating step is performed while cooling the tensile stress field.

  A fifteenth aspect of the invention is the dividing method according to the fourteenth aspect, wherein the irradiation heating step is performed while cooling the tensile stress field by jetting a cooling fluid.

  The invention according to claim 16 is the dividing method according to any one of claims 7 to 15, wherein, in the scribing step, predetermined in each of a first direction and a second direction orthogonal to each other. A plurality of scribe lines are formed at a pitch, and in the irradiation heating step, after performing irradiation heating along the scribe lines extending in the first direction, the extension extending in the second direction. Irradiation heating is performed along the scribe line.

  The invention according to claim 17 is the dividing method according to claim 16, wherein, in the irradiation heating step, an irradiation beam diameter of the second laser light is set to be equal to or smaller than a pitch when the scribe line is formed. It is characterized by that.

  According to the invention of Claims 1 to 17, the second laser beam is irradiated along the scribe line formed with high precision in advance at the planned cutting position of the workpiece by irradiating the first laser beam. By heating the inside of the workpiece, tensile stress is applied to the scribe line, and the crack progresses from the scribe line to the non-scribe surface sequentially along the extending direction of the scribe line. The workpiece can be divided with high accuracy. Moreover, since the tensile stress can be generated by laser heating in the same apparatus following the formation of the scribe line, highly accurate cutting can be performed efficiently. In addition, since it is not necessary to place the workpiece again on the breaker that performs cutting from a conventional scribing apparatus, the cutting process is simplified.

It is a figure which shows the principle of a parting process typically. It is a figure which shows typically the mode in the middle of parting. It is a figure which shows the structure of the cutting device 100 schematically. 2 is a diagram showing a detailed configuration of a scribing laser optical system 20. FIG. 2 is a diagram showing a detailed configuration of a heating laser optical system 30. FIG. It is a schematic diagram which shows a mode that the tensile-stress field SF2 is cooled in the structure by which the laser beam LBh for a heating is irradiated to the scribe surface W1. It is a schematic diagram which shows a mode that the tensile-stress field SF2 is cooled in the structure by which the laser beam LBh for a heating is irradiated to the scribe surface W1. It is a figure which shows roughly an example of a structure which implement | achieves injection of the cooling gas CG in the cutting device 100. FIG.

<Basic principles of processing>
First, the basic principle of processing (parting processing) according to the present embodiment will be described. In the cutting process performed in the present embodiment, the scribe line SL is formed by irradiating the first laser beam (scribing laser beam) to the scheduled cutting position of the workpiece (dividing object) W. After that, a stress field is generated in the vicinity of the scribe line SL by performing heating (laser heating) by irradiation with a second laser beam (heating laser beam), thereby causing a crack (crack from the scribe line SL as an initial crack). ) To divide the work piece.

  As the workpiece W, for example, a brittle material such as a glass plate or a sapphire substrate, or a unit pattern two-dimensionally formed by a thin film layer on the surface of a substrate made of such a brittle material (hereinafter referred to as a patterned substrate). ).

  FIG. 1 is a diagram schematically showing the principle of parting. More specifically, FIG. 1 shows a state in which laser heating is performed by irradiating the laser beam LBh for heating along a scribe line SL formed in advance on the workpiece W.

  In the following description, the surface of the workpiece W on which the scribe line SL is formed or the surface on which the scribe line SL is scheduled to be formed is referred to as a scribe surface W1, and the surface opposite to the scribe surface W1 is defined as a non-surface. This is referred to as a scribe surface W2. Further, FIG. 1 shows a state where the laser beam LBh for heating scans the scribe surface W1 by moving in the scanning direction indicated by the arrow AR1 (which is of course also the extending direction of the scribe line SL). Instead, while the heating laser beam LBh is fixedly irradiated at a certain irradiation position, the workpiece W is moved by a moving means (not shown), whereby the arrow AR1 by the heating laser beam LBh. A mode in which relative scanning in the direction is realized may be employed.

In the case shown in FIG. 1, the case where the laser beam LBh for heating which absorbs on the surface of the workpiece W is irradiated is illustrated. Such a heating laser beam LBh includes a CO ₂ laser (wavelength: 9.4 μm to 10.6 μm) which is a long wavelength laser. In such a case, when the heating laser beam LBh is irradiated, the irradiation region of the heating laser beam LBh on the scribe surface W1 of the workpiece W is heated and expands to become a compressive stress field SF1 as shown in FIG. . On the other hand, the outer peripheral region of the compressive stress field SF1 contracts to become a tensile stress field SF2. When the scribe line SL is included in the tensile stress field SF2, the tensile stress TS acts on the workpiece W on the side of the scribe line SL. Due to the action of the tensile stress TS, the crack CR advances from the scribe line SL toward the scheduled cutting position L0 on the non-scribe surface W2. In addition, since the heating laser beam LBh is relatively scanned along the scribe line SL as described above, the tensile stress field SF2 also moves along the scribe line SL. Then, the portion where the crack CR progresses toward the non-scribe surface W2 side transitions along the extending direction of the scribe line SL, that is, the scanning direction of the heating laser beam LBh. Therefore, if the heating laser beam LBh is irradiated from one end to the other end of the scribe line SL provided at the planned slicing position on the scribe surface W1 side, the planned slicing position at the entire scribe line SL formation position. Since the progress of the crack CR to L0 can be sequentially generated, the workpiece W can be divided as a result.

  However, when the heating laser beam LBh that is absorbed on the surface of the workpiece W is used as shown in FIG. 1, the irradiation region of the heating laser beam LBh is necessarily the compressive stress field SF1 on the scribe surface W1. Therefore, the compressive stress CS acts on the scribe line SL in the irradiation region of the heating laser beam LBh. Since the compressive stress CS acts so as to prevent the crack CR from progressing in the tensile stress field SF2 described above, the crack CR only propagates around the irradiation region of the heating laser beam LBh in the case shown in FIG. It will be.

  Therefore, in the present embodiment, irradiation heating with the laser beam LBh for heating is performed in such a manner that absorption is generated inside the workpiece W. FIG. 2 is a cross-sectional view schematically showing a state in the middle of the cutting process according to the present embodiment. 2 illustrates the case where the scribe line SL is formed as a groove, the form of the scribe line SL is not limited to this as described later (the same applies to FIG. 6).

  In the case shown in FIG. 2, the point that the heating laser beam LBh is irradiated along the scribe line SL is the same as the case shown in FIG. 1, but it is heated by absorbing the heating laser beam LBh and compressed stress. The field SF1 is a region inside the workpiece W. And the outer peripheral area | region of the said area | region including the scribe surface W1 in which the scribe line SL is formed becomes the tensile stress field SF2. In such a case, since the formation position of the scribe line SL is included only in the tensile stress field SF2, the progress of the crack CR to the non-scribe surface W2 is not hindered by the action of the compressive stress. Therefore, the crack CR progresses efficiently.

  Further, when the workpiece W is divided in such a manner, the scribe line SL formed accurately at a predetermined position on the scribe surface W1 after accurately positioning the workpiece W is used as an initial crack. The crack CR is advanced toward the scribe surface W2. Usually, the thickness of the workpiece W is sufficiently small compared to the length of the scribe line SL, and the tensile stress field SF2 formed by the heating laser beam LBh is relatively uniform. Hard to occur. That is, in this embodiment, it is possible to perform division with excellent accuracy. As a result, it is possible to divide with an accuracy of μm order.

  In addition, when a substrate with a pattern, such as an LED manufacturing substrate, which is a sapphire substrate having an LED pattern two-dimensionally formed on the surface, is divided into individual pieces for each unit pattern (on a chip basis), When set in a lattice shape, a plurality of scribe lines SL are sequentially formed in the first direction and the second direction orthogonal to each other, and then the laser beam LBh for heating is sequentially applied in each direction. Is heated. In this case, when laser heating is performed along the scribe line SL (first scribe line) extending in a first direction by the heating laser beam LBh, another scribe line SL (second In the vicinity of the lattice point with the scribe line), the crack CR slightly progresses to the non-scribe surface W2 even in the second scribe line extending in the second direction. However, even in such a case, by performing laser heating along the second scribe line later, it is possible to perform division without any problem in accuracy.

As the scribing laser beam, an appropriate pulse laser beam may be selected and used according to the material of the workpiece W or the like. For example, if the LED manufacturing substrate, which is a patterned substrate manufactured using a sapphire substrate or a sapphire substrate, is the workpiece W, the third harmonic (wavelength 355 nm) of the YAG laser is used. This is a preferred example. Further, in order to improve the accuracy and certainty of the division at the planned division position, it is desirable that the scribe line SL be formed as thin as possible. Therefore, the scribe laser beam has an irradiation range of about several μm to several tens of μm ( (Irradiation beam diameter). In addition, from the viewpoint of processing efficiency (energy utilization efficiency), the scribing laser light is combined on the scribe surface W1 of the workpiece W or in the vicinity of the internal scribe surface W1 (range from the scribe surface W1 to about several tens of μm). Irradiated in a sharp manner. In the present embodiment, the irradiation beam diameter is an energy value of 1 / e ² or more of the center maximum value assuming that the energy distribution of the cross section of the laser beam to be irradiated is a Gaussian distribution shape. The diameter of a certain area.

  In addition, the scribe line SL may be in a form in which a triangular or wedge-shaped groove portion formed by evaporating a substance at the irradiation position of the scribe laser beam is the scribe line SL, A mode in which the altered region having a triangular shape or a wedge shape in sectional view formed by melting and re-solidifying (melt-modifying) a substance at the irradiated position may be a scribe line SL. Irradiation conditions (pulse width, repetition frequency, peak power density, scanning speed, etc.) of the scribing laser beam are determined depending on which mode is used. Moreover, although the case where the scribe line SL is continuously formed is illustrated in FIG. 1, the form of the scribe line SL is not limited to this. For example, the aspect in which the scribe line SL is formed in a dotted line shape or a broken line shape along the scheduled division position may be used.

  On the other hand, as the heating laser beam LBh, it is preferable to use the fundamental wave of an Er-YAG laser (wavelength 2940 nm) or the fundamental wave of an Nd-YAG laser (wavelength 1064 nm). If it is these laser beams, the absorption in the inside of glass or sapphire can be produced suitably. Note that, unlike the scribe laser beam irradiated for the purpose of processing the workpiece, which is the formation of the scribe line SL, the heating laser beam LBh is a compressive stress formed in the heating region by heating the workpiece. Irradiation is performed for the purpose of forming a tensile stress field SF2 around the field SF1. Therefore, the irradiation range of the heating laser beam LBh is larger than that of the scribing laser beam in order to prevent the workpiece from being broken or altered or to form the tensile stress field SF2 as wide as possible. It's okay. For example, when the thickness of the workpiece is 150 μm, it may be about 100 μm to 1000 μm.

  However, in the case of cutting a rectangular chip from a substrate with a pattern, the irradiation beam diameter of the heating laser beam LBh is set to be equal to or smaller than the planar size of the chip (approximately equal to the pitch of the planned cutting position). To do. If the irradiation beam diameter is made larger than this, it is not preferable because the division is not performed well and a chip having a predetermined shape cannot be obtained.

<Severing device>
Next, a cutting apparatus for cutting a workpiece based on the above-described processing principle will be described. FIG. 3 is a diagram schematically showing the configuration of the cutting apparatus 100.

  As shown in FIG. 3, the cutting apparatus 100 mainly includes a stage unit 10, a scribing laser optical system 20, a heating laser optical system 30, and a position reading optical system 40. In addition, the cutting device 100 includes, for example, a CPU, ROM, RAM, and the like (not shown), and exchanges various signals with the scribing laser optical system 20, the heating laser optical system 30, the position reading optical system 40, and the like. Thus, a control system 50 for controlling the operation of each component is provided. Note that the control system 50 may be incorporated in the main body of the cutting apparatus 100 as an integral part of other components, or may be configured by, for example, a personal computer and provided separately from the main body of the cutting apparatus 100. An aspect may be sufficient.

  The stage unit 10 mainly includes an XY stage 11 and a processing stage 12 provided on the XY stage 11.

  The XY stage 11 is movable in two directions (X direction and Y direction) orthogonal to each other in the horizontal plane (in the XY plane) based on the drive control signal sg1 from the control system 50. The position information signal sg2 of the XY stage 11 is constantly fed back to the control system.

  The processing stage 12 is a part for mounting and fixing the workpiece W thereon. The processing stage 12 includes a suction mechanism (not shown), and the workpiece W is suction-fixed to the upper surface 12a of the processing stage 12 by operating the suction mechanism based on the suction control signal sg3 from the control system 50. It is configured as follows. Further, the processing stage 12 is provided with a rotation drive mechanism (not shown) so that it can rotate in a horizontal plane based on a rotation control signal sg4 from the control system 50.

  In addition, although illustration is abbreviate | omitted in FIG. 3, when fixing to the stage 12 for a process, an adhesive film is affixed on the non-scribe surface W2 side (mounting surface side) of the to-be-processed W, and also with this film The aspect which fixes the to-be-processed object W may be sufficient.

  The scribing laser optical system 20 is a part that irradiates the workpiece W with the scribing laser light based on the scribing laser control signal sg5 provided from the control system 50.

  FIG. 4 is a diagram showing a detailed configuration of the scribing laser optical system 20. As shown in FIG. 4, the scribing laser optical system 20 adjusts the amount of light of the laser oscillator 21 that is a light source (emission source) of the scribing laser light LBs and the scribing laser light LBs emitted from the laser oscillator 21. Attenuator 22 for the purpose and an objective lens 23 for adjusting the focus of the scribing laser beam LBs are mainly provided. As described above, since the pulse laser beam corresponding to the material or the like of the workpiece W is used as the scribe laser beam LBs, the laser oscillator 21 corresponds to the type of the scribe laser beam LBs to be used. It only has to be selected.

  The scribing laser optical system 20 also includes a mirror 24 that appropriately switches the direction of the optical path of the scribing laser beam LBs by reflecting the scribing laser beam LBs. 4 illustrates the case where only one mirror 24 is provided. However, the number of mirrors 24 is not limited to this, and layout requirements within the scribing laser optical system 20 or further within the cutting apparatus 100 are illustrated. For other reasons, more mirrors 24 may be provided, and the optical path of the scribing laser beam LBs may be appropriately set.

  More specifically, the laser oscillator 21 is provided with a shutter 21a for switching between emission / non-emission of the scribing laser beam LBs. The opening / closing operation of the shutter 21a is controlled based on an ON / OFF control signal sg5a which is a kind of scribe laser control signal sg5. The adjustment of the amount of the scribing laser light LBs in the attenuator 22 is controlled based on an output power control signal sg5b which is a kind of the scribing laser control signal sg5.

  In the scribing laser optical system 20, the scribing laser beam LBs emitted from the laser oscillator 21 and adjusted in light amount by the attenuator 22 is near the scribing surface W1 of the workpiece W or the inner scribing surface W1 (the scribing surface W1). To the range of about several tens of μm), and the position of the objective lens 23 is adjusted so that the irradiation beam diameter is about several μm to several tens of μm. Thereby, a favorable scribe line SL is formed.

  The heating laser optical system 30 is a part that irradiates the workpiece W with the heating laser light based on the heating laser control signal sg6 provided from the control system 50.

  FIG. 5 is a diagram showing a detailed configuration of the heating laser optical system 30. As shown in FIG. 5, the heating laser optical system 30 adjusts the amount of light of the laser beam LBh emitted from the laser oscillator 31, which is a light source (emission source) of the heating laser beam LBh, and the laser oscillator 31. The attenuator 32 for adjusting, the beam adjusting mechanism 33 for adjusting the irradiation range of the heating laser beam LBh to the workpiece W, and the objective lens 34 for adjusting the focus of the heating laser beam LBh are mainly provided. As described above, since the Er-YAG laser or the Nd-YAG laser is used as the heating laser beam LBh, the laser oscillator 31 is an oscillator of one of the lasers.

  The heating laser optical system 30 is also provided with a mirror 35 that appropriately switches the direction of the optical path of the heating laser beam LBh by reflecting the heating laser beam LBh. FIG. 5 illustrates the case where only one mirror 35 is provided, but the number of mirrors 35 is not limited to this, and the layout requirements in the heating laser optical system 30 or further in the cutting apparatus 100 are not limited. For other reasons, more mirrors 35 may be provided, and the optical path of the heating laser beam LBh may be appropriately set.

  More specifically, the laser oscillator 31 is provided with a shutter 31a for switching between emission / non-emission of the heating laser beam LBh. The opening / closing operation of the shutter 31a is controlled based on an ON / OFF control signal sg6a which is a kind of the heating laser control signal sg6. The adjustment of the amount of the heating laser beam LBh in the attenuator 32 is controlled based on an output power control signal sg6b which is a kind of the heating laser control signal sg6.

  The beam adjusting mechanism 33 is provided for adjusting the irradiation range of the heating laser beam LBh linearly emitted from the laser oscillator 31. The beam adjusting mechanism 33 is realized by appropriately combining various lenses, for example, and adjusting the positions of these lenses to irradiate the workpiece W with the heating laser beam LBh in an appropriate irradiation range. It can be done. 5 exemplifies the case where the workpiece W is irradiated with an irradiation range larger than the beam diameter when emitted from the laser oscillator 31 by the adjustment by the beam adjustment mechanism 33. doing.

  The position reading optical system 40 images the workpiece W attracted and fixed to the processing stage 12 with a CCD camera (not shown) or the like, and supplies the obtained captured image data to the control system 50 as an image information signal sg7. Based on the obtained image information signal sg7, the control system 50 sets the movement range of the XY stage 11, the irradiation position of the scribing laser beam LBs and the heating laser beam LBh, and the like.

  In the cutting apparatus 100 having the above configuration, the workpiece W is moved to the scribe laser optical system 20 by moving the XY stage 11 while the workpiece W is attracted and fixed to the machining stage 12. The heating laser optical system 30 and the position reading optical system 40 can be opposed to each other from below. In this case, the workpiece W is fixed to the processing stage 12 so that the scribe surface W1 is the upper surface (non-mounting surface).

  Then, the XY stage 11 is moved while irradiating the workpiece W with the scribe laser beam LBs from the scribe laser optical system 20 in a state where the workpiece W is disposed opposite to the scribe laser optical system 20. Thus, relative scanning of the scribing laser beam LBs with respect to the workpiece W is realized. A scribe line SL can be formed by relatively scanning the scribe laser beam LBs along a predetermined expected cutting position of the scribe surface W1.

  Similarly, the XY stage 11 is moved while the workpiece W is irradiated with the heating laser beam LBh from the heating laser optical system 30 while the workpiece W is disposed opposite to the heating laser optical system 30. By doing so, relative scanning of the heating laser beam LBh with respect to the workpiece W is realized. By making the heating laser beam LBh relatively scan along the scribe line SL formed by the irradiation of the scribe laser beam LBs, the crack CR is scheduled to be divided from the scribe line SL to the non-scribe surface W2 of the workpiece W. The workpiece W can be divided by the progress toward the position.

  Further, in the cutting apparatus 100, the workpiece W is imaged by the position reading optical system 40 in a state in which the workpiece W is disposed opposite to the position reading optical system 40, and based on the obtained captured image data, An alignment operation for correcting the inclination (posture) of the workpiece W in the horizontal plane can be performed. Specifically, the control system 50 determines the inclination (XY stage 11) of the workpiece W in the horizontal plane based on the image content of the captured image data (for example, the alignment mark arrangement position and the repeated pattern arrangement position). The rotation control signal sg4 is given to the processing stage 12 so that the inclination is canceled, and the processing stage 12 is rotated. As a main for specifying the inclination of the workpiece W in the horizontal plane, a known method such as a pattern matching method can be applied.

  In the case of normal cutting, imaging by the position reading optical system 40 and subsequent alignment in a state where the workpiece W is fixed to the processing stage 12 so that the scribe surface W1 is an upper surface (non-mounting surface). After the processing, the scribe line SL is formed by the scribe laser optical system 20, and further, the heating laser light LBh is irradiated in the heating laser optical system 30, whereby the workpiece W is formed. Divided.

<Cooling of tensile stress field>
There is a method of cooling the tensile stress field SF2 as a method of causing the crack CR to progress more effectively in the tensile stress field SF2.

  6 and 7 are schematic views showing a state in which the tensile stress field SF2 is cooled in the configuration in which the laser beam LBh for heating is irradiated on the scribe surface W1. 6 is a cross-sectional view of the workpiece W perpendicular to the extending direction of the scribe line SL, and FIG. 7 is a top view of the workpiece W.

  6 and FIG. 7, when the scribe surface W1 is scanned in the scanning direction indicated by the arrow AR1 with the laser beam LBh for heating, the rear portion in the scanning direction of the formed tensile stress field SF2 is cooled. Gas CG is injected.

  When cooling is performed in this manner, the temperature difference between the cooled portion of the tensile stress field SF2 and the compressive stress field SF1 heated by irradiation with the heating laser beam LBh becomes higher, and the tensile stress field SF2 Tensile stress is increased. Thereby, the certainty of progress of crack CR is improved. As a result, the workpiece W can be divided more accurately.

  As the cooling gas CG, a gas that does not react with the workpiece W, such as an inert gas, may be appropriately used.

  FIG. 8 is a diagram schematically showing an example of a configuration for realizing the injection of the cooling gas CG in the cutting apparatus 100 shown in FIGS. 3 to 5. That is, in the case shown in FIG. 8, the nozzle 36 for injecting the cooling gas CG is attached to the heating laser optical system 30, and the cooling gas CG supplied from the cooling gas supply source 37 through the supply pipe 38 is supplied. The nozzle 36 can be ejected toward the tensile stress field SF2 in synchronization with the scanning (relative scanning) of the heating laser beam LBh.

  However, the mode of cooling the tensile stress field SF2 is not limited to that by the injection of the cooling gas CG as described above. If there is no problem such as reactivity with the workpiece and corrosion of the cutting apparatus, the liquid is used. Cooling may be performed. In other words, cooling by a fluid containing gas and liquid may be performed. Moreover, the aspect which cools by making a solid refrigerant | coolant approach or contact the tensile stress field SF2 may be sufficient.

  As described above, according to the present embodiment, the laser beam for heating is irradiated along the scribe line that is formed in advance at the planned cutting position of the workpiece by irradiating the laser beam for scribe. By heating the inside of the work piece, tensile stress is applied to the scribe line, and the progress of cracks from the scribe line to the non-scribe surface is sequentially generated along the extending direction of the scribe line. You can divide things. Moreover, the crack can be more efficiently caused by cooling the tensile stress field.

  Moreover, the scribing process for forming the scribe line by irradiating the scribing laser beam can be performed after positioning the processing target position with high accuracy. Therefore, a highly accurate cutting process can be efficiently performed by forming a scribe line with high accuracy at the planned cutting position in the same device and subsequently generating tensile stress by laser heating. Can be performed.

DESCRIPTION OF SYMBOLS 10 Stage part 11 XY stage 12 Processing stage 20 Scribe laser optical system 21 Laser oscillator 21a Shutter 22 Attenuator 23 Objective lens 24 Mirror 30 Heating laser optical system 31 Laser oscillator 31a Shutter 32 Attenuator 33 Beam adjustment mechanism 34 Objective lens 35 Mirror 36 Nozzle 37 Cooling gas supply source 38 Supply pipe 40 Optical system 50 Control system 100 Cutting device CG Cooling gas CR Crack CS Compressive stress L0 Scheduled cutting position LBh Heating laser beam LBs Scribing laser beam SF1 Compressive stress field SF2 Tensile stress field SL Scribe line TS Tensile stress W Workpiece W1 (Workpiece) scribe surface W2 (Workpiece) non-scribe surface

Claims (2)

An apparatus for performing processing to divide a workpiece,
A stage for mounting and fixing the workpiece;
By irradiating the first laser beam emitted from the first emission source onto the scribe surface which is the upper surface of the workpiece placed and fixed on the stage while being relatively scanned with respect to the stage. Scribing means for ablating the scribe surface to form a scribe line;
The workpiece is irradiated by irradiating the second laser light emitted from the second emission source and absorbed inside the workpiece along the scribe line while being relatively scanned with respect to the stage. Irradiation heating means for heating the inside along the scribe line,
A cooling fluid supply means for injecting a cooling fluid to the workpiece;
With
The irradiation heating means generates a tensile stress field formed in the vicinity of the scribe line inside the workpiece including the scribe surface by the irradiation of the second laser light by the cooling fluid supply means. The second laser beam is moved by being relatively scanned along the scribe line while being cooled by jetting a cooling fluid, thereby causing the scribe line to be located in the tensile stress field. The progress of cracks from the scribe line to the non-scribe surface is sequentially generated along the scribe line, thereby dividing the workpiece.
A cutting device characterized by that. A method of dividing a workpiece,
A first laser beam is emitted from a first emission source, and the scribe surface of the workpiece is irradiated with the first laser beam, thereby causing ablation on the scribe surface to form a scribe line. Scribing process to
A second laser beam that is absorbed inside the workpiece is emitted from a second emission source, and the second laser beam is irradiated along the scribe line from the scribe surface side. An irradiation heating step of heating the inside of the workpiece along the scribe line;
With
In the irradiation heating step, the second stress is generated while cooling the tensile stress field formed in the vicinity of the scribe line inside the workpiece including the scribe surface by the irradiation of the second laser beam. The laser beam is moved by relatively scanning along the scribe line, and thereby the crack progresses from the scribe line to the non-scribe surface caused by the scribe line being positioned in the tensile stress field. Are divided along the scribe line to divide the workpiece.
A method for dividing a workpiece, characterized in that.