JP2012240107A - Laser processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing method that can accurately cut an effective part having a chamfered angle part off a plate-like processing object.SOLUTION: The laser processing method is to cut an effective part 18 having a chamfered angle part 19 off a plate-like processing object 1. By relatively moving the light focal point P of a laser beam L along one side face 18a of the effective part 18 to the angle part 19 and along a cutoff planned line 51 extending through the angle part 19, a modified region is formed inside the processing object 1 along the cutoff planned line 51. After that, by relatively moving the light focal point P of the laser beam L along a cutoff planned line 53 extending along the chamfering face 19a of the angle part 19, the modified region is formed inside the processing object 1 along the cutoff planned line 53.

Description

  The present invention relates to a laser processing method for cutting out an effective portion having chamfered corners from a plate-like workpiece.

  As a laser processing method in the above technical field, the following is known (for example, see Patent Document 1). That is, when moving the condensing point of the laser beam along the straight line portion of the planned cutting line, the spot shape of the condensing point of the laser light is made elliptical, and its long axis is made to coincide with the straight line portion of the planned cutting line. When moving the condensing point of the laser beam along the curved portion of the planned cutting line, the spot shape of the condensing point of the laser beam is made circular.

JP 2008-062289 A

  However, in the laser processing method as described above, when the laser beam is irradiated along the curved portion of the planned cutting line, a crack extends in an unnecessary direction from the curved portion, and as a result, from the workpiece. The effective part to be cut out may be damaged.

  Then, an object of this invention is to provide the laser processing method which makes it possible to cut out the effective part which has the chamfered corner | angular part from a plate-shaped workpiece precisely.

  The laser processing method of the present invention is a laser processing method for cutting out an effective portion having a chamfered corner from a plate-like workpiece, and is provided along one side surface of the effective portion that reaches the corner and has a corner. A laser beam condensing point is relatively moved along a first scheduled cutting line extending so as to pass through the section, whereby a first cutting point is formed along the first scheduled cutting line. A first step of forming the modified region in the workpiece, and a laser beam along the second scheduled cutting line extending along the chamfered surface of the corner after the first step. A second step of forming a second modified region serving as a starting point of cutting inside the workpiece along the second scheduled cutting line by relatively moving the condensing point of It is characterized by providing.

  In this laser processing method, the first modified region serving as a starting point of cutting is formed along a first scheduled cutting line extending along one side surface of the effective portion reaching the corner portion and passing through the corner portion. After that, a second modified region serving as a starting point for cutting is formed along a second scheduled cutting line extending along the chamfered surface of the corner. Thereby, the crack which generate | occur | produces from the 2nd modification area | region formed along the chamfering surface will extend so that the 1st modification area | region already formed may be followed. Therefore, according to this laser processing method, it is possible to prevent the crack from extending in an unnecessary direction from the chamfered surface, and as a result, the effective portion having the chamfered corner portion can be accurately detected from the plate-like workpiece. It is possible to cut out well.

  In the laser processing method of the present invention, when the third scheduled cutting line extends along the other side surface of the effective portion that reaches the corner and passes through the corner, the laser processing method is performed before the second step. The third modified region that is the starting point of cutting along the third scheduled cutting line is moved by moving the laser beam condensing point relatively along the third scheduled cutting line. You may further provide the 3rd process formed in the inside of a thing. In this case, the crack generated from the second modified region formed along the chamfered surface extends along each of the first modified region and the third modified region that are already formed. Become. Therefore, it is possible to more reliably prevent the crack from extending from the chamfered surface in an unnecessary direction.

  In the laser processing method of the present invention, the first scheduled cutting line may extend along the boundary surface between adjacent effective portions. In this case, cracks generated from the second modified region formed along the chamfered surface of one of the effective portion, the first modified region has already been formed along the interface of the useful portion adjacent It will extend along. Therefore, it is possible to prevent a crack from extending from the chamfered surface of one effective portion into the other effective portion.

  In the laser processing method of the present invention, the first scheduled cutting line may extend along the boundary surface between the effective portion and the outer edge portion including the side surface of the workpiece. In this case, it is possible to make the quality of the side surface of the effective portion uniform by cutting off the side surface of the workpiece from the effective portion.

  In the laser processing method of the present invention, the first scheduled cutting line may extend so as to cross the workpiece. In this case, the crack generated from the end portion of the first modified region formed along the first scheduled cutting line reaches the side surface of the workpiece. Therefore, it is possible to prevent the crack from extending in an unnecessary direction from the end portion of the first modified region.

  In the laser processing method of the present invention, the chamfered surface may be a convex curved surface or a substantially flat surface. In any case, it is possible to prevent the crack from extending in an unnecessary direction from the chamfered surface.

  In the laser processing method of the present invention, in the first step, the laser beam is pulse-oscillated at the first frequency, the focusing point is relatively moved at the first speed, and in the second step, the first step is performed. The laser beam may be pulse-oscillated at a second frequency lower than the first frequency, and the focal point may be relatively moved at a second speed lower than the first speed. According to this, the second modified region can be formed with high accuracy along the chamfered surface, and the second modified region can be formed so as to easily extend the crack.

  In the laser processing method of the present invention, the first cutting is performed by causing the first modified region and the crack generated from the second modified region to reach the front surface and the back surface of the workpiece after the second step. A fourth step of cutting the workpiece along the scheduled line and the second scheduled cutting line may be further provided. According to this, the effective part which has the chamfered corner | angular part can be accurately cut out from a plate-shaped process target object.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to cut out the effective part which has the chamfered corner | angular part from a plate-shaped process target object with sufficient precision.

It is a schematic block diagram of the laser processing apparatus used for formation of a modification area | region. It is a top view of the processing target object used as the object of formation of a modification field. It is sectional drawing along the III-III line of the workpiece of FIG. It is a top view of the processing target after laser processing. It is sectional drawing along the VV line of the workpiece of FIG. It is sectional drawing along the VI-VI line of the processing target object of FIG. It is a top view of the processing target used as the object of the laser processing method of a 1st embodiment of the present invention. It is a top view of the processed object in which the laser processing method of a 1st embodiment of the present invention is carried out. It is a top view of the processed object in which the laser processing method of a 1st embodiment of the present invention is carried out. It is a top view of the process target object used as the object of the laser processing method of the 2nd Embodiment of this invention. It is a top view of the processing target object in which the laser processing method of a 2nd embodiment of the present invention is carried out. It is a top view of the processing target object in which the laser processing method of a 2nd embodiment of the present invention is carried out. It is a top view of the process target object used as the object of the laser processing method of the 3rd Embodiment of this invention. It is a top view of the processing target object in which the laser processing method of the 3rd embodiment of the present invention is carried out. It is a top view of the processing target object in which the laser processing method of the 3rd embodiment of the present invention is carried out. It is a top view of the process target object used as the object of the laser processing method of the 4th Embodiment of this invention. It is a top view of the processing target object in which the laser processing method of the 4th embodiment of the present invention is carried out. It is a top view of the processing target object in which the laser processing method of the 4th embodiment of the present invention is carried out. It is a figure which shows the process order of a comparative example, and the photograph of a process result. It is a figure which shows the process order of 1st Example, and the photograph of a process result. It is a figure which shows the photograph of the process order of a 2nd Example, and a process result.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted.

  In the laser processing method of one embodiment of the present invention, the modified region that is the starting point of cutting inside the workpiece along the planned cutting line by irradiating the processing target with laser light along the planned cutting line Form. First, the formation of the modified region will be described with reference to FIGS.

  As shown in FIG. 1, a laser processing apparatus 100 includes a laser light source 101 that oscillates a laser beam L, a dichroic mirror 103 that is arranged so as to change the direction of the optical axis (optical path) of the laser beam L, and A condensing lens 105 for condensing the laser light L. Further, the laser processing apparatus 100 includes a support base 107 for supporting the workpiece 1 irradiated with the laser light L condensed by the condensing lens 105, and a stage 111 for moving the support base 107. And a laser light source control unit 102 for controlling the laser light source 101 in order to adjust the output, pulse width, etc. of the laser light L, and a stage control unit 115 for controlling the drive of the stage 111.

  In the laser processing apparatus 100, the laser beam L emitted from the laser light source 101, the internal dichroic by the mirror 103 is changed direction by 90 ° of the optical axis, the support base 107 object 1 placed on The light is condensed by the condensing lens 105. At the same time, the stage 111 is moved, and the workpiece 1 is moved relative to the laser beam L along the planned cutting line 5. As a result, a modified region along the planned cutting line 5 is formed on the workpiece 1.

  As the workpiece 1, plate-like members (for example, substrates, wafers, etc.) made of various materials (for example, glass, semiconductor material, piezoelectric material, etc.) are used. As shown in FIG. 2, a scheduled cutting line 5 for cutting the workpiece 1 is set in the workpiece 1. The planned cutting line 5 is a virtual line extending linearly. When forming a modified region inside the workpiece 1, as shown in FIG. 3, the laser beam L is projected along the planned cutting line 5 in a state where the focused point P is aligned with the inside of the workpiece 1. It moves relatively (that is, in the direction of arrow A in FIG. 2). Thereby, as shown in FIGS. 4 to 6, the modified region 7 is formed inside the workpiece 1 along the planned cutting line 5, and the modified region 7 formed along the planned cutting line 5 is formed. It becomes the cutting start area 8.

  In addition, the condensing point P is a location where the laser light L is condensed. Further, the planned cutting line 5 is not limited to a straight line, but may be a curved line, or may be a line actually drawn on the surface 3 of the workpiece 1 without being limited to a virtual line. In addition, the modified region 7 may be formed continuously or intermittently. Further, the modified region 7 may be in the form of a line or a dot. In short, the modified region 7 only needs to be formed at least inside the workpiece 1. In addition, there may be cases where cracks starting from the modified region 7 is formed, cracks and modified region 7, the outer surface of the object 1 may be exposed to (surface, back surface, or outer peripheral surface).

  Incidentally, the laser light L here passes through the workpiece 1 and is particularly absorbed near the condensing point inside the workpiece 1, thereby forming the modified region 7 in the workpiece 1. (Ie, internal absorption laser processing). Therefore, since the laser beam L is hardly absorbed by the surface 3 of the workpiece 1, the surface 3 of the workpiece 1 is not melted. In general, when a removed portion such as a hole or a groove is formed by being melted and removed from the front surface 3 (surface absorption laser processing), the processing region gradually proceeds from the front surface 3 side to the back surface side.

  By the way, the modified region formed in the present embodiment refers to a region where the density, refractive index, mechanical strength, and other physical characteristics are different from the surroundings. Examples of the modified region include a melt treatment region, a crack region, a dielectric breakdown region, a refractive index change region, and the like, and there is a region where these are mixed. Furthermore, as the modified region, there are a region in which the density of the modified region in the material to be processed is changed as compared with the density of the non-modified region, and a region in which lattice defects are formed (collectively these are high-density regions). Also known as the metastatic region).

In addition, the area where the density of the melt treatment area, the refractive index change area, the modified area has changed compared to the density of the non-modified area, and the area where lattice defects are formed are further included in these areas and the modified areas. In some cases, cracks (cracks, microcracks, etc.) are included in the interface between the non-modified region and the non-modified region. The included crack may be formed over the entire surface of the modified region, or may be formed in only a part or a plurality of parts. Examples of the processing object 1 include a substrate or wafer made of silicon, glass, LiTaO ₃ or sapphire (Al ₂ O ₃ ), or a material including such a substrate or wafer.

  Further, in the present embodiment, the modified region 7 is formed by forming a plurality of modified spots (processing marks) along the planned cutting line 5. The modified spot is a modified portion formed by one pulse shot of pulsed laser light (that is, one pulse of laser irradiation: laser shot). Examples of the modified spot include a crack spot, a melting treatment spot, a refractive index change spot, or a mixture of at least one of these.

This modified spot, the required cutting accuracy, flatness of the required cutting plane, the thickness of the object, type, taking into account the crystal orientation and the like, suitably the length of the size and generated cracks It is preferable to control.
[First Embodiment]

  FIG. 7 is a plan view of a workpiece to be processed by the laser processing method according to the first embodiment of the present invention. As shown in FIG. 7, in the first embodiment, a rectangular plate-like workpiece 1 made of glass is provided in a plurality of rows and columns (here, two rows) without providing a space along the side surfaces 1a and 1b. This is a case where a plurality (four in this case) of rectangular plate-shaped effective portions 18 are cut out from the workpiece 1. Effective portion 18, substantially parallel pair of side surfaces 18a in the row direction, 18a, substantially parallel pair of side surfaces 18b in the column direction, 18b, and to have a chamfered four corners 19 are, from the object 1 Cut out. The corner portion 19 is rounded so that the chamfered surface 19a is a convex curved surface. Such an effective part 18 is used for a protective substrate of a display of a portable terminal.

  In the workpiece 1, a scheduled cutting line (first scheduled cutting line) 51, a scheduled cutting line (third scheduled cutting line) 52 and a scheduled cutting line (second scheduled cutting line) 53 are set.

  The planned cutting line 51 extends along one side surface 18 a that reaches the corner 19 and through the corner 19. Here, the planned cutting line 51 extends along the boundary surface between the adjacent effective portions 18 and 18 in the column direction. Furthermore, the cutting scheduled line 51 extends so as to cross the workpiece 1. That is, the planned cutting line 51 extends between a pair of side surfaces 1b, 1b substantially parallel to the column direction. Note that the planned cutting line 51 passes through the corner portion 19 so as to intersect the intersection line between the one side surface 18a of the effective portion 18 and the chamfered surface 19a of the corner portion 19 (here, substantially orthogonal). This means that the planned cutting line 51 is extended.

  The planned cutting line 52 extends along the other side surface 18 b reaching the corner 19 and through the corner 19. Here, the planned cutting line 52 extends along the boundary surface between the effective portions 18 and 18 adjacent to each other in the row direction. Further, the planned cutting line 52 extends so as to cross the workpiece 1. That is, the planned cutting line 52 extends between a pair of side surfaces 1a and 1a substantially parallel to the row direction. Note that the planned cutting line 52 passes through the corner portion 19 so as to intersect the intersection line between the other side surface 18b of the effective portion 18 and the chamfered surface 19a of the corner portion 19 (in this case, substantially orthogonal). This means that the planned cutting line 52 is extended.

  The planned cutting line 53 extends along the chamfered surface 19 a of the corner portion 19. That is, the planned cutting line 53 is an intersection line between one side surface 18a of the effective portion 18 and the chamfered surface 19a of the corner portion 19, and an intersection line between the other side surface 18b of the effective portion 18 and the chamfered surface 19a of the corner portion 19. Crossed between.

  As described above, a plurality of effective portions 18 are cut out from the workpiece 1 in which the scheduled cutting lines 51, 52, and 53 are set as follows. First, the workpiece 1 is placed on the support base 107 of the laser processing apparatus 100. At this time, the processing object 1 is held, for example, by sticking a tape on the back surface 4 of the processing object 1 or by forming the support 107 in a porous shape and vacuum-adsorbing the processing object 1. In this state, the stage 111 is driven so that the condensing point P of the laser beam L is located inside by a predetermined distance from the surface 3 of the workpiece 1.

  Subsequently, as illustrated in FIG. 8A, the processing object 1 is irradiated with the laser light L along the scheduled cutting line 51 using the surface 3 of the processing object 1 as the laser light incident surface. That is, the condensing point P of the laser beam L is relatively moved (scanned) along the scheduled cutting line 51. At this time, the laser beam L is pulse-oscillated at the frequency F1, and the condensing point P is relatively moved at the speed V1. If the frequency F1 is 50 kHz and the speed V1 is 500 mm / s, the pulse pitch (speed V1 / frequency F1) of the laser light L is 10 μm. By such irradiation with the laser beam L, a modified region (first modified region) 71 serving as a starting point of cutting is formed inside the workpiece 1 along the planned cutting line 51 (FIG. 9A). )reference).

  Subsequently, as illustrated in FIG. 8A, the processing target 1 is irradiated with the laser light L along the planned cutting line 52 with the surface 3 of the processing target 1 as the laser light incident surface. That is, the condensing point P of the laser light L is relatively moved along the planned cutting line 52. At this time, the laser beam L is pulse-oscillated at the frequency F2, and the condensing point P is relatively moved at the speed V2. If the frequency F2 is 50 kHz and the speed V2 is 500 mm / s, the pulse pitch of the laser light L (speed V2 / frequency F2) is 10 μm. By such irradiation with the laser beam L, a modified region (third modified region) 72 serving as a starting point of cutting is formed inside the workpiece 1 along the planned cutting line 52 (FIG. 9A). )reference).

  Here, as long as the stage 111 can move in two axial directions in a plane substantially perpendicular to the optical axis of the laser light L and can rotate around the optical axis of the laser light L, as follows: The stage 111 is driven. That is, the stage 111 is driven so that the condensing point P of the laser beam L moves relatively along the scheduled cutting line 51. Subsequently, in this state (without driving the stage 111 so as to rotate around the optical axis of the laser beam L), the condensing point P of the laser beam L relatively moves along the planned cutting line 52. The stage 111 is driven.

  On the other hand, if the stage 111 can move in one axial direction in a plane substantially perpendicular to the optical axis of the laser light L and can rotate about the optical axis of the laser light L, the stage is as follows. 111 is driven. That is, the stage 111 is driven so that the condensing point P of the laser beam L moves relatively along the scheduled cutting line 51. Subsequently, the stage 111 is driven so as to rotate 90 ° around the optical axis of the laser light L, and in this state, the condensing point P of the laser light L is relatively moved along the planned cutting line 52. The stage 111 is driven.

  The movement of the condensing point P of the laser light L along the planned cutting line 52 and the formation of the modified region 72 are performed first, and the converging point P of the laser light L along the planned cutting line 51 is moved. Further, the modified region 71 may be formed later. Further, the laser light L side (the laser light source 101, the dichroic mirror 103, the condensing lens 105, etc.) is moved in order to relatively move the condensing point P of the laser light L along the scheduled cutting lines 51 and 52. Alternatively, both the workpiece 1 side (the support base 107 and the like) and the laser beam L side may be moved.

  After the modified regions 71 and 72 are formed along the planned cutting lines 51 and 52, the laser beam is applied to the workpiece 1 along the planned cutting line 53 for each effective portion 18, as shown in FIG. 8B. L is irradiated. That is, the condensing point P of the laser light L is relatively moved along the scheduled cutting line 53 for each effective portion 18. At this time, the laser beam L is pulse-oscillated at a frequency F3 lower than the frequencies F1 and F2, and the condensing point P is relatively moved at a speed V3 lower than the speeds V1 and V2. If the frequency F3 is 1 kHz and the speed V3 is 10 mm / s, the pulse pitch (speed V3 / frequency F3) of the laser light L is 10 μm. By irradiation with such laser light L, a modified region (second modified region) 73 serving as a starting point of cutting is formed inside the workpiece 1 along the planned cutting line 53 (FIG. 9A). )reference).

  Here, when irradiating the workpiece 1 with the laser beam L along the scheduled cutting line 53 for each effective portion 18, as shown in FIG. 8B, the laser beam L along the outer edge of the effective portion 18. The stage 111 is driven so that the condensing point P of the lens moves in a rectangular ring shape. At this time, on the chamfered surface 19a of each corner portion 19, the irradiation of the laser beam L is switched ON so that the laser beam L is irradiated onto the workpiece 1 (solid arrow in FIG. 8B), and each side surface. In 18a and 18b, the irradiation of the laser beam L is switched OFF so that the workpiece 1 is not irradiated with the laser beam L (broken arrows in FIG. 8B). Then, on each of the side surfaces 18a and 18b, the stage 111 is driven so that the condensing point P of the laser light L moves at a speed higher than the speed V3 (for example, a speed corresponding to the speed V1 or V2).

  Note that the adjustment of the repetition frequency of the laser light L is realized by adding an optical element such as an ultrasonic light modulator (AOM) to the laser light source 101 and the laser light source control unit 102. By thinning out the repetition frequency by AOM, the repetition frequency can be lowered from the frequency F1, F2 to the frequency F3. Further, in order to relatively move the condensing point P of the laser beam L along the scheduled cutting line 53, the laser beam L side may be moved, or both the workpiece 1 side and the laser beam L side may be moved. May be moved.

  As shown in FIG. 9A, after forming the modified regions 71, 72, 73 along the planned cutting lines 51, 52, 53, an external force is applied along the planned cutting lines 51, 52, 53, By causing the cracks generated from the modified regions 71, 72, 73 to reach the front surface 3 and the back surface 4 of the workpiece 1, the workpiece 1 is cut along the scheduled cutting lines 51, 52, 53. As described above, as shown in FIG. 9B, the effective portion 18 having the chamfered corner portion 19 is cut out from the workpiece 1.

  As described above, in the laser processing method of the first embodiment, the modified regions 71 and 72 are formed along the scheduled cutting lines 51 and 52 (that is, along the side surfaces 18a and 18b of the effective portion 18). Thereafter, the modified region 73 is formed along the planned cutting line 53 (that is, along the chamfered surface 19a of the effective portion 18). Thereby, the crack which generate | occur | produces from the modification | reformation area | region 73 formed along the chamfering surface 19a extends so that the modification | reformation area | regions 71 and 72 already formed may be followed. Therefore, according to the laser processing method of the first embodiment, and reliably prevent cracks from spreading in unwanted directions from the chamfered surface 19a, plate-like processing effective portion 18 having a chamfered corner portion 19 The object 1 can be accurately cut out. Such a laser processing method is extremely effective when a plurality of effective portions 18 are cut out from a single workpiece 1.

  Here, the scheduled cutting lines 51 and 52 extend along the boundary surface between the adjacent effective portions 18 and 18. Thus, a crack generated from the modified region 73 formed along the chamfered surface 19a of one of the effective portion 18, the effective portion 18 modified regions already formed along the interface between 71 adjacent , 72 to extend along. Accordingly, it is possible to prevent the crack from extending from the chamfered surface 19 a of one effective portion 18 into the other effective portion 18.

  Further, the scheduled cutting lines 51 and 52 extend so as to cross the workpiece 1. Thereby, the crack which generate | occur | produces from the edge part of the modification | reformation area | regions 71 and 72 formed along the scheduled cutting lines 51 and 52 reaches the side surfaces 1a and 1b of the workpiece 1. FIG. Therefore, it is possible to prevent the cracks from extending from the end portions of the modified regions 71 and 72 in unnecessary directions.

  Further, when the modified region 73 is formed along the planned cutting line 53 (that is, along the chamfered surface 19a of the effective portion 18), along the planned cutting lines 51 and 52 (that is, the effective portion 18). Compared with the case where the modified regions 71 and 72 are formed (along the side surfaces 18a and 18b), the relative moving speed of the condensing point P of the laser light L is lowered. Thereby, the situation where the condensing point P of the laser beam L passes outside the chamfered surface 19a with respect to the effective portion 18 can be prevented, and the modified region 73 can be accurately formed along the chamfered surface 19a. .

Further, when the relative moving speed of the condensing point P of the laser beam L is lowered and the modified region 73 is formed along the planned cutting line 53, the modified region is formed along the planned cutting lines 51 and 52. Compared with the case of forming 71 and 72, the repetition frequency of the laser beam L is lowered. If the relative moving speed of the condensing point P of the laser beam L is lowered without lowering the repetition frequency of the laser beam L, the pulse pitch becomes shorter, so that the modified spot (formed by irradiation of one pulse of the laser beam L) is formed. The modified region 73 is formed in a dense state), and as a result, there is a possibility that cracks are difficult to extend in the thickness direction of the workpiece 1. By lowering the relative moving speed of the condensing point P of the laser light L and lowering the repetition frequency of the laser light L, it is possible to prevent the pulse pitch from being shortened, and to modify the effective portion 18 along the chamfered surface 19a. The quality region 73 can be formed so as to facilitate extension of cracks.
[Second Embodiment]

  FIG. 10 is a plan view of a workpiece to be processed by the laser processing method according to the second embodiment of the present invention. As shown in FIG. 10, in the second embodiment, a rectangular plate-like workpiece 1 made of glass is provided in a plurality of rows and columns (here, two rows and two columns) by providing a space along the side surfaces 1a and 1b. This is different from the first embodiment in that it is cut into rows. Hereinafter, the second embodiment will be described with a focus on differences from the first embodiment.

  In the workpiece 1, scheduled cutting lines (first scheduled cutting lines) 51a and 51b, scheduled cutting lines (third scheduled cutting lines) 52a and 52b, and scheduled cutting lines 53 are set.

  The planned cutting lines 51 a and 51 b extend along the one side surface 18 a reaching the corner 19 and through the corner 19. Here, the planned cutting line 51a extends along the boundary surface between the adjacent effective portions 18 and 18 in the column direction. Further, the planned cutting line 51 b extends along the boundary surface between the effective portion 18 and the outer edge portion 21 a including the side surface 1 a of the workpiece 1. Further, the scheduled cutting lines 51 a and 51 b extend so as to cross the workpiece 1. That is, the planned cutting lines 51a and 51b extend between a pair of side surfaces 1b and 1b substantially parallel to the column direction.

  The planned cutting lines 52 a and 52 b extend along the other side surface 18 b reaching the corner 19 and through the corner 19. Here, the planned cutting line 52a extends along the boundary surface between the effective portions 18 and 18 adjacent in the row direction. Further, the planned cutting line 52b extends along the boundary surface between the effective portion 18 and the outer edge portion 21b including the side surface 1b of the workpiece 1. Further, the scheduled cutting lines 52 a and 52 b extend so as to cross the workpiece 1. That is, the scheduled cutting lines 52a and 52b extend between a pair of side surfaces 1a and 1a substantially parallel to the row direction.

  As described above, a plurality (four in this case) of effective portions 18 are cut out from the workpiece 1 on which the scheduled cutting lines 51a, 51b, 52a, 52b, 53 are set as follows. First, the processing object 1 is placed on the support 107 of the laser processing apparatus 100, and then, as shown in FIG. 11A, the surface 3 of the processing object 1 is scheduled to be cut with the laser light incident surface. The workpiece 1 is irradiated with the laser beam L along the lines 51a and 51b. That is, the condensing point P of the laser beam L is relatively moved along the scheduled cutting lines 51a and 51b. At this time, the laser beam L is pulse-oscillated at the frequency F1, and the condensing point P is relatively moved at the speed V1. Thus, the modified region 71 is formed inside the workpiece 1 along the scheduled cutting lines 51a and 51b (see FIG. 12A).

  Subsequently, as illustrated in FIG. 11A, the processing target 1 is irradiated with the laser light L along the scheduled cutting lines 52 a and 52 b with the surface 3 of the processing target 1 as the laser light incident surface. That is, the condensing point P of the laser beam L is relatively moved along the scheduled cutting lines 52a and 52b. At this time, the laser beam L is pulse-oscillated at the frequency F2, and the condensing point P is relatively moved at the speed V2. Thus, the modified region 72 is formed inside the workpiece 1 along the scheduled cutting lines 52a and 52b (see FIG. 12A).

  In addition, the condensing point P of the laser beam L along the scheduled cutting lines 52a and 52b is first moved and the modified region 72 is formed, and the laser beam L is focused along the planned cutting lines 51a and 51b. The movement of the point P and the formation of the modified region 71 may be performed later.

  After the modified regions 71 and 72 are formed along the scheduled cutting lines 51a, 51b, 52a, and 52b, as shown in FIG. 1 is irradiated with a laser beam L. That is, the condensing point P of the laser light L is relatively moved along the scheduled cutting line 53 for each effective portion 18. At this time, the laser beam L is pulse-oscillated at a frequency F3 lower than the frequencies F1 and F2, and the condensing point P is relatively moved at a speed V3 lower than the speeds V1 and V2. Thereby, the modified region 73 is formed inside the workpiece 1 along the planned cutting line 53 (see FIG. 12A).

  In addition, when irradiating the processing target 1 with the laser beam L along the scheduled cutting line 53 for each effective portion 18, switching ON / OFF of the irradiation with the laser beam L is performed as in the first embodiment. And the relative moving speed of the condensing point P of the laser beam L is switched.

  As shown in FIG. 12 (a), cutting lines 51a, 51b, 52a, along a 52 b, 53 after forming the modified regions 71, 72, 73, cutting lines 51a, 51b, 52a, 52 b, 53 It reacted with external force along, by reaching the front face 3 and rear face 4 of the crack generated from the modified region 71, 72, 73 the object 1, cutting lines 51a, 51b, 52a, the 52 b, 53 The workpiece 1 is cut along. As described above, as shown in FIG. 12B, the effective portion 18 having the chamfered corner portion 19 is cut out from the workpiece 1.

  As described above, in the laser processing method of the second embodiment, cutting lines 51a, 51b, 52a, along a 52 b (i.e., the side surface 18a of the effective portion 18, along 18b) modified region 71, 72 is formed, and then the modified region 73 is formed along the planned cutting line 53 (that is, along the chamfered surface 19a of the effective portion 18). Thereby, the crack which generate | occur | produces from the modification | reformation area | region 73 formed along the chamfering surface 19a extends so that the modification | reformation area | regions 71 and 72 already formed may be followed. Therefore, according to the laser processing method of the second embodiment, it is possible to reliably prevent cracks from extending in an unnecessary direction from the chamfered surface 19a, and the effective portion 18 having the chamfered corner portions 19 to be processed into a plate shape. The object 1 can be accurately cut out.

  Here, the scheduled cutting lines 51a and 52a extend along the boundary surface between the adjacent effective portions 18 and 18. Thus, a crack generated from the modified region 73 formed along the chamfered surface 19a of one of the effective portion 18, the effective portion 18 modified regions already formed along the interface between 71 adjacent , 72 to extend along. Accordingly, it is possible to prevent the crack from extending from the chamfered surface 19 a of one effective portion 18 into the other effective portion 18.

  Further, the scheduled cutting lines 51b and 52b extend along the boundary surface between the effective portion 18 and the outer edge portions 21a and 21b. Thereby, the side surfaces 1a and 1b of the workpiece 1 can be cut off from the effective portion 18, and the quality of the side surfaces 18a and 18b of the effective portion 18 can be made uniform.

  Further, the scheduled cutting lines 51 a, 51 b, 52 a, 52 b extend so as to cross the workpiece 1. Thus, cutting lines 51a, 51b, 52a, cracks generated from the end of the modified region 71, 72 formed along the 52b would lead to side 1a, 1b of the object 1. Therefore, it is possible to prevent the cracks from extending from the end portions of the modified regions 71 and 72 in unnecessary directions.

Also, along the line to cut 53 (i.e., along the chamfered surface 19a of the effective portion 18) when forming the modified regions 73, cutting lines 51a, 51b, 52a, along a 52 b (i.e., side 18a of the effective portion 18, along 18b) compared with the case of forming the modified regions 71 and 72, to the relative moving speed of the converging point P of laser light L, and the repetition frequency of the laser beam L low. As a result, the modified region 73 can be formed with high accuracy along the chamfered surface 19a, and the modified region 73 can be formed so as to easily extend a crack.
[Third Embodiment]

  FIG. 13 is a plan view of a workpiece to be processed by the laser processing method according to the third embodiment of the present invention. As shown in FIG. 13, the third embodiment is the first embodiment in that a rectangular plate-shaped workpiece 1 made of glass is cut into a plurality of rows and one column (here, two rows and one column). And different. Hereinafter, the third embodiment will be described with a focus on differences from the first embodiment.

  In the workpiece 1, a scheduled cutting line 51 and a planned cutting line 53 are set. A plurality (two in this case) of effective portions 18 are cut out from the workpiece 1 in which the scheduled cutting lines 51 and 53 are set as described below. First, the workpiece 1 is placed on the support 107 of the laser processing apparatus 100, and then, as shown in FIG. 14 (a), the surface 3 of the workpiece 1 is scheduled to be cut with the laser light incident surface. The workpiece 1 is irradiated with the laser light L along the line 51. That is, the condensing point P of the laser light L is relatively moved along the scheduled cutting line 51. At this time, the laser beam L is pulse-oscillated at the frequency F1, and the condensing point P is relatively moved at the speed V1. Thus, the modified region 71 is formed inside the workpiece 1 along the planned cutting line 51 (see FIG. 15A).

  After the modified region 71 is formed along the planned cutting line 51, the workpiece 1 is irradiated with the laser light L along the planned cutting line 53 for each effective portion 18, as shown in FIG. . That is, the condensing point P of the laser light L is relatively moved along the scheduled cutting line 53 for each effective portion 18. At this time, the laser light L is pulse-oscillated at a frequency F3 lower than the frequency F1, and the condensing point P is relatively moved at a speed V3 lower than the speed V1. Thereby, the modified region 73 is formed inside the workpiece 1 along the planned cutting line 53 (see FIG. 15A).

  In addition, when irradiating the processing target 1 with the laser beam L along the scheduled cutting line 53 for each effective portion 18, switching ON / OFF of the irradiation with the laser beam L is performed as in the first embodiment. And the relative moving speed of the condensing point P of the laser beam L is switched.

  As shown in FIG. 15A, after forming the modified regions 71 and 73 along the planned cutting lines 51 and 53, an external force is applied along the planned cutting lines 51 and 53 to modify the modified regions 71 and 73. The workpiece 1 is cut along the scheduled cutting lines 51 and 53 by causing the cracks generated from the above to reach the front surface 3 and the back surface 4 of the workpiece 1. As described above, as shown in FIG. 15 (b), the effective portion 18 having the chamfered corner portion 19 is cut out from the workpiece 1.

  As described above, in the laser processing method according to the third embodiment, the modified region 71 is formed along the planned cutting line 51 (that is, along the side surface 18a of the effective portion 18), and then the planned cutting is performed. The modified region 73 is formed along the line 53 (that is, along the chamfered surface 19a of the effective portion 18). As a result, a crack generated from the modified region 73 formed along the chamfered surface 19a extends along the modified region 71 that has already been formed. Therefore, according to the laser processing method of the third embodiment, the crack is reliably prevented from extending from the chamfered surface 19a in an unnecessary direction, and the effective portion 18 having the chamfered corner portion 19 is processed into a plate-like shape. The object 1 can be accurately cut out.

  Here, the planned cutting line 51 extends along the boundary surface between the adjacent effective portions 18 and 18. Thereby, the crack generated from the modified region 73 formed along the chamfered surface 19a of one effective portion 18 is the modified region 71 already formed along the boundary surface between the adjacent effective portions 18 and 18. It will be extended along. Accordingly, it is possible to prevent the crack from extending from the chamfered surface 19 a of one effective portion 18 into the other effective portion 18.

  Furthermore, the planned cutting line 51 extends so as to cross the workpiece 1. Thereby, the crack generated from the end portion of the modified region 71 formed along the planned cutting line 51 reaches the side surface 1 b of the workpiece 1. Therefore, it is possible to prevent the crack from extending from the end portion of the modified region 71 in an unnecessary direction.

Also, along the line to cut 53 (i.e., along the chamfered surface 19a of the effective portion 18) when forming the modified regions 73 along the line to cut 51 (i.e., the side surface 18a of the effective portion 18 Along with the case where the modified region 71 is formed, the relative moving speed of the condensing point P of the laser beam L and the repetition frequency of the laser beam L are lowered. As a result, the modified region 73 can be formed with high accuracy along the chamfered surface 19a, and the modified region 73 can be formed so as to easily extend a crack.
[Fourth Embodiment]

  FIG. 16 is a plan view of a workpiece to be processed by the laser processing method according to the fourth embodiment of the present invention. As shown in FIG. 16, in the fourth embodiment, a rectangular plate-shaped workpiece 1 made of glass is provided with a space along its side surfaces 1a and 1b, and a space between adjacent effective portions 18 and 18 is provided. Is different from the first embodiment in that it is cut into 1 row and multiple columns (here, 1 row and 2 columns). Hereinafter, the fourth embodiment will be described focusing on differences from the first embodiment.

  In the processing object 1, a scheduled cutting line 51b, scheduled cutting lines 52b and 52c, and a planned cutting line 53 are set.

  The planned cutting line 51 b extends along one side surface 18 a that reaches the corner 19 and passes through the corner 19. Here, the planned cutting line 51 b extends along the boundary surface between the effective portion 18 and the outer edge portion 21 a including the side surface 1 a of the workpiece 1. Furthermore, the planned cutting line 51 b extends so as to cross the workpiece 1. That is, the planned cutting line 51b extends between a pair of side surfaces 1b and 1b substantially parallel to the column direction.

  The planned cutting lines 52 b and 52 c extend along the other side surface 18 b reaching the corner 19 and through the corner 19. Here, the planned cutting line 52 b extends along the boundary surface between the effective portion 18 and the outer edge portion 21 b including the side surface 1 b of the workpiece 1. Further, the planned cutting line 52c extends along the boundary surface between the effective portion 18 and the intermediate portion 22 interposed between the adjacent effective portions 18 and 18. Further, the planned cutting lines 52b and 52c extend so as to cross the workpiece 1. That is, the planned cutting lines 52b and 52c extend between a pair of side surfaces 1a and 1a substantially parallel to the row direction.

  As described above, a plurality (two in this case) of effective portions 18 are cut out from the workpiece 1 on which the scheduled cutting lines 51b, 52b, 52c, 53 are set as follows. First, the processing object 1 is placed on the support 107 of the laser processing apparatus 100, and then, as shown in FIG. 17A, the surface 3 of the processing object 1 is scheduled to be cut with the laser light incident surface. The workpiece 1 is irradiated with the laser beam L along the line 51b. That is, the condensing point P of the laser beam L is relatively moved along the planned cutting line 51b. At this time, the laser beam L is pulse-oscillated at the frequency F1, and the condensing point P is relatively moved at the speed V1. Thereby, the modified region 71 is formed inside the workpiece 1 along the planned cutting line 51b (see FIG. 18A).

  Subsequently, as illustrated in FIG. 17A, the processing target 1 is irradiated with the laser light L along the scheduled cutting lines 52 b and 52 c with the surface 3 of the processing target 1 as the laser light incident surface. That is, the condensing point P of the laser beam L is relatively moved along the scheduled cutting lines 52b and 52c. At this time, the laser beam L is pulse-oscillated at the frequency F2, and the condensing point P is relatively moved at the speed V2. Thereby, the modified region 72 is formed inside the workpiece 1 along the scheduled cutting lines 52b and 52c (see FIG. 18A).

  In addition, the condensing point P of the laser beam L along the scheduled cutting lines 52b and 52c is first moved and the modified region 72 is formed, and the condensing point P of the laser beam L along the scheduled cutting lines 51b is formed. The movement and the formation of the modified region 71 may be performed later.

  After the modified regions 71 and 72 are formed along the scheduled cutting lines 51b, 52b, and 52c, as shown in FIG. Laser light L is irradiated. That is, the condensing point P of the laser light L is relatively moved along the scheduled cutting line 53 for each effective portion 18. At this time, the laser beam L is pulse-oscillated at a frequency F3 lower than the frequencies F1 and F2, and the condensing point P is relatively moved at a speed V3 lower than the speeds V1 and V2. Thereby, the modified region 73 is formed inside the workpiece 1 along the planned cutting line 53 (see FIG. 18A).

  In addition, when irradiating the processing target 1 with the laser beam L along the scheduled cutting line 53 for each effective portion 18, switching ON / OFF of the irradiation with the laser beam L is performed as in the first embodiment. And the relative moving speed of the condensing point P of the laser beam L is switched.

  As shown in FIG. 18 (a), cutting lines 51b, 52 b, after forming the modified regions 71, 72, 73 along the 52c, 53, cutting lines 51b, 52 b, along the 52c, 53 an external force It reacted with, by reaching the front face 3 and rear face 4 of the crack generated from the modified region 71, 72, 73 the object 1, cutting lines 51b, 52 b, the object along the 52c, 53 1 Disconnect. As described above, as shown in FIG. 18B, the effective portion 18 having the chamfered corner portion 19 is cut out from the workpiece 1.

  As described above, in the laser processing method of the fourth embodiment, the modified regions 71 and 72 are formed along the scheduled cutting lines 51b, 52b, and 52c (that is, along the side surfaces 18a and 18b of the effective portion 18). Then, the modified region 73 is formed along the planned cutting line 53 (that is, along the chamfered surface 19a of the effective portion 18). Thereby, the crack which generate | occur | produces from the modification | reformation area | region 73 formed along the chamfering surface 19a extends so that the modification | reformation area | regions 71 and 72 already formed may be followed. Therefore, according to the laser processing method of the fourth embodiment, the crack is surely prevented from extending from the chamfered surface 19a in an unnecessary direction, and the effective portion 18 having the chamfered corner portion 19 is processed into a plate-like shape. The object 1 can be accurately cut out.

  Here, the scheduled cutting lines 51b and 52b extend along the boundary surface between the effective portion 18 and the outer edge portions 21a and 21b. Thereby, the side surfaces 1a and 1b of the workpiece 1 can be cut off from the effective portion 18, and the quality of the side surfaces 18a and 18b of the effective portion 18 can be made uniform.

  Further, the scheduled cutting lines 51 b, 52 b, 52 c extend so as to cross the workpiece 1. Thereby, the crack which generate | occur | produces from the edge part of the modification | reformation area | regions 71 and 72 formed along the scheduled cutting lines 51b, 52b, and 52c reaches the side surfaces 1a and 1b of the workpiece 1. Therefore, it is possible to prevent the cracks from extending from the end portions of the modified regions 71 and 72 in unnecessary directions.

  Further, when the modified region 73 is formed along the planned cutting line 53 (that is, along the chamfered surface 19a of the effective portion 18), along the planned cutting lines 51b, 52b, and 52c (that is, the effective portion). Compared with the case where the modified regions 71 and 72 are formed (along the 18 side surfaces 18a and 18b), the relative moving speed of the condensing point P of the laser light L and the repetition frequency of the laser light L are lowered. As a result, the modified region 73 can be formed with high accuracy along the chamfered surface 19a, and the modified region 73 can be formed so as to easily extend a crack.

  Next, comparative examples and examples will be described. Here, a tempered glass plate having an outer shape of 60 mm × 60 mm and a thickness of 900 μm was prepared as a workpiece. The workpiece is irradiated with laser light under the conditions of an output of 20 μJ, a repetition frequency of 1 kHz, and a relative moving speed of the condensing point of 10 mm / s. The modified regions of 5 rows (“distances between the laser light incident surface of the object to be processed and the focal point” were 380 μm, 310 μm, 240 μm, 170 μm, and 100 μm, respectively) were formed. And in order to cut | disconnect a process target object along a cutting plan line, the external force was made to act along each cutting plan line by hand.

  FIG. 19 is a diagram illustrating a photograph of the processing order and processing results of the comparative example. As shown in FIG. 19 (a), laser light is irradiated along the planned cutting lines (dotted line in FIG. 19 (a)) (solid arrows in FIG. 19 (a)), and each cutting planned line is applied. Five rows of modified regions were formed. The processing order is the order of the planned cutting lines along the chamfered surfaces of R5 to R10 (unit mm), the planned cutting lines in the vertical and horizontal directions, the square ring (outer shape 30 mm × 30 mm). In this comparative example, the planned horizontal and vertical cutting lines were not crossed so that the planned cutting line along the chamfered surface crossed between the end points of the vertical and horizontal cutting planned lines. As a result, as shown in FIG. 19 (b), an unnecessary crack that deviated from the planned cutting line extended from the upper right end of the lower right chamfered surface to the upper right.

  FIG. 20 is a diagram illustrating a photograph of the processing order and processing results of the first example. As shown in FIG. 20 (a), laser light is irradiated along the planned cutting lines (dotted line in FIG. 20 (a)) (solid arrows in FIG. 20 (a)), and each cutting planned line is applied. Five rows of modified regions were formed. The processing order is the order of the planned cutting lines along the chamfered surfaces of R5 to R10 (unit mm), the planned cutting lines in the vertical and horizontal directions, the square ring (outer shape 30 mm × 30 mm). In the first embodiment, the vertical and horizontal cutting lines are crossed so that the cutting line along the chamfered surface extends between the intermediate points of the vertical and horizontal cutting lines. As a result, as shown in FIG. 20 (b), an unnecessary crack deviated from the planned cutting line did not extend, and the workpiece could be accurately cut along each planned cutting line.

  FIG. 21 is a diagram showing a photograph of the processing order and processing results of the second embodiment. As shown in FIG. 21 (a), laser light is irradiated along the planned cutting lines (dotted line in FIG. 21 (a)) (solid line arrows in FIG. 21 (a)), and each cutting planned line is applied. Five rows of modified regions were formed. The processing order is the order of the vertical and horizontal cutting scheduled lines, the square annular (outer shape 30 mm × 30 mm) cutting planned lines, and the cutting scheduled lines along the chamfered surfaces of C1 to C5 (unit mm). In the second embodiment, the vertical and horizontal cutting lines are crossed so that the cutting line along the chamfered surface extends between the intermediate points of the vertical and horizontal cutting lines. As a result, as shown in FIG. 21 (b), an unnecessary crack deviated from the planned cutting line did not extend, and the workpiece could be accurately cut along each planned cutting line.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, a plurality of rows of modified regions may be formed so as to be aligned in the thickness direction of the workpiece with respect to each scheduled cutting line. Even in that case, according to the present invention, the effective portion having the chamfered corner portion can be accurately cut out from the plate-like workpiece. The number of columns of the modified region for one scheduled cutting line can be determined as appropriate according to the thickness of the workpiece.

  Moreover, in the said embodiment, although the external force was made to act along a cutting plan line and the crack which generate | occur | produced from the modification | reformation area | region was reached to the surface and back surface of a workpiece, it is not limited to this. With the formation of the modified region of one or more rows for each line to cut (any without the action of external force to the workpiece), reaching the crack generated from the modified region on the front surface and the back surface of the object Thus, the workpiece may be cut along the planned cutting line.

  Further, the corner portion of the effective portion may be chamfered so that the chamfered surface thereof is substantially flat. Also in this case, according to the present invention, to prevent the cracks from spreading in unwanted directions from the chamfered surfaces, the effective portion having a chamfered corner can be cut precisely from the plate-shaped workpiece .

  Moreover, as a material of a processing target object, it is not limited to glass, Various materials are applicable. As the modified region, depending on the type of material and the irradiation condition of the laser beam, a melt-processed region, a crack region, a dielectric breakdown region, a refractive index change region, and the like, or a region in which these are mixed is formed.

  1 ... workpiece, 1a, 1b ... side, 3 ... surface, 4 ... rear surface, 18 ... effective portion, 19 ... corner, 19a ... chamfered surface, 21a, 21b ... outer edge, 51, 51a, 51b ... cut Line (first cutting planned line), 52, 52a, 52b ... Cutting scheduled line (third cutting scheduled line), 53 ... Cutting planned line (second cutting planned line), 71 ... Modified region (first , 72 ... modified region (third modified region), 73 ... modified region (second modified region), L ... laser beam, P ... condensing point.

Claims (9)

A laser processing method for cutting out an effective part having a chamfered corner from a plate-like workpiece,
By relatively moving the condensing point of the laser beam along the first cutting scheduled line extending along one side surface of the effective portion reaching the corner portion and passing through the corner portion, A first step of forming a first modified region inside the workpiece along the first scheduled cutting line;
After the first step, the second focusing point of the laser light is relatively moved along a second scheduled cutting line extending along the chamfered surface of the corner portion, whereby the second And a second step of forming a second modified region inside the object to be processed along a planned cutting line. When the third scheduled cutting line extends along the other side surface of the effective portion that reaches the corner and passes through the corner,
Prior to the second step, by moving the focusing point of the laser light relatively along the third scheduled cutting line, the workpiece is moved along the third scheduled cutting line. The laser processing method according to claim 1, further comprising a third step of forming a third modified region therein.   3. The laser processing method according to claim 1, wherein the first scheduled cutting line extends along a boundary surface between the adjacent effective portions.   The said 1st cutting plan line is extended so that the boundary surface of the said effective part and the outer edge part containing the side surface of the said workpiece may be followed, The Claim 1 or 2 characterized by the above-mentioned. Laser processing method.   The laser processing method according to claim 1, wherein the first scheduled cutting line extends so as to cross the workpiece.   The laser processing method according to claim 1, wherein the chamfered surface is a convex curved surface.   The laser processing method according to claim 1, wherein the chamfered surface is a substantially flat surface. In the first step, the laser beam is pulse-oscillated at a first frequency, and the focusing point is relatively moved at a first speed,
In the second step, the laser light is pulse-oscillated at a second frequency lower than the first frequency, and the focusing point is relatively moved at a second speed lower than the first speed. It moves, The laser processing method as described in any one of Claims 1-7 characterized by the above-mentioned.   After the second step, by causing the cracks generated from the first modified region and the second modified region to reach the front surface and the back surface of the workpiece, the first scheduled cutting line and The laser processing method according to claim 1, further comprising a fourth step of cutting the object to be processed along the second scheduled cutting line.