JP2013154604A - Laser processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing method that precisely cuts out an effective part having a chamfered corner part from a plate-like object with a reinforced glass plate.SOLUTION: The laser processing method comprises: a first step of forming a first modifying region, along a first predetermined cutting line 51 in a reinforced glass plate 10, for generating a first crack extending in a thickness direction of an object 1 by relatively moving a focus of a laser beam along the first predetermined cutting line 51 extending along a chamfered surface 18a at least of a corner part 18; and after the first step, a second step of forming a second modifying region, along a second predetermined cutting line 52 in the reinforced glass plate 10, for generating a second crack extending in a thickness direction of an object 1 by relatively moving the focus of the laser beam along the second predetermined cutting line 52 extending from the outside of an effective part 17 to the corner part 18.

Description

  The present invention relates to a laser processing method for cutting out an effective portion from a plate-like processing object including a tempered glass plate.

  As a laser processing method in the above technical field, a plate-shaped workpiece is irradiated with a laser beam, thereby forming a modified region inside the workpiece along the planned cutting line, and generated from the modified region. It is known that a workpiece is cut along a planned cutting line by extending a crack in the thickness direction of the workpiece (for example, see Patent Document 1).

JP 2004-343008 A

  However, by carrying out the laser processing method as described above, when trying to cut out an effective portion having a chamfered corner portion from a plate-like workpiece having a tempered glass plate, there is a burr or the like at the corner portion. This may cause cutting quality to deteriorate at the corners.

  Then, an object of this invention is to provide the laser processing method which can cut out the effective part which has the chamfered corner | angular part accurately from the plate-shaped process target provided with a tempered glass board.

  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 processing object including a tempered glass plate, and at least along the chamfered surface of the corner. A first modified region that generates a first crack extending in the thickness direction of the workpiece by relatively moving the condensing point of the laser light along the first scheduled cutting line extending to A first step formed inside the tempered glass plate along the first scheduled cutting line, and a second planned cutting line extending from the outside of the effective portion to the corner after the first step. The second modified region that generates the second crack extending in the thickness direction of the object to be processed by relatively moving the condensing point of the laser beam, the tempered glass plate along the second scheduled cutting line 2nd process formed in the inside.

  In this laser processing method, the first modified region is formed along the first scheduled cutting line extending along the chamfered surface of the corner portion, and then extended from the outside of the effective portion to the corner portion. A second modified region is formed along the existing second cutting scheduled line. When the first modified region and the second modified region are formed in this order, the first crack is easily extended along the first scheduled cutting line with the following reason. In other words, the tempered glass plate has a tensile stress layer and a compressive stress layer formed on both sides of the tensile stress layer, so that a crack is easily generated from the modified region and is easily extended. Therefore, when the first modified region is formed after the second modified region is formed, a part of the first crack generated from the first modified region deviates from the first scheduled cutting line toward the second modified region. It becomes easy to generate burrs at the corners. On the other hand, when the second modified region is formed after the first modified region is formed, a situation in which a part of the first crack extends toward the second modified region is prevented, and the first cutting scheduled The first crack is easily extended along the line with high accuracy. Therefore, according to this laser processing method, the effective part which has the chamfered corner | angular part can be accurately cut out from the plate-shaped process target provided with a tempered glass board.

  Here, in the first step, the first crack may reach the front surface and the back surface of the workpiece, and in the second step, the second crack may reach the front surface and the back surface of the workpiece. According to this, it is possible to more reliably prevent a situation in which a part of the first crack extends toward the second modified region, and it is possible to extend the first crack along the first scheduled cutting line. .

  In addition, when the first scheduled cutting line extends along the end surface of the effective portion that reaches the chamfered surface of the side surface of the effective portion, the first cutting planned line extends along the end surface; You may set a 2nd cutting plan line so that it may continue. In addition, when the chamfered surface is a convex curved surface, the second scheduled cutting line may be set so as to be in contact with a portion extending along the chamfered surface in the first scheduled cutting line. According to these, for example, also in the second scheduled cutting line for cutting off the portion around the effective portion, a part of the second crack generated from the second modified region is removed from the second scheduled cutting line and the first modified It is possible to suppress extension toward the quality region.

  Further, in the laser processing method described above, when a plurality of effective portions are cut out from the workpiece, the third cutting scheduled line extending so as to pass between adjacent effective portions is provided before the first step. The third modified region that generates the third crack extending in the thickness direction of the object to be processed is moved along the third scheduled cutting line by relatively moving the condensing point of the laser beam. You may further provide the 3rd process formed inside. According to this, in one of the adjacent effective portions, a part of the first and second cracks generated from the first and second modified regions deviate from the first and second scheduled cutting lines and are adjacent to each other. Even if it extends toward the other side of the part, the extension is stopped by the third modified region and the third crack, so that the other of the adjacent effective parts can be prevented from being damaged.

  At this time, in the third step, the third crack may reach the front surface and the back surface of the workpiece. According to this, extension of a part of the 1st and 2nd cracks which deviated from the 1st and 2nd scheduled cutting lines can be stopped more certainly.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the laser processing method which can cut out the effective part which has the chamfered corner | angular part accurately from the plate-shaped process target provided with a tempered glass board.

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 process target object used as the object of the laser processing method of 1st Embodiment of this invention, and an effective part. It is a top view of the processing target 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 processing target 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 2nd Embodiment of this invention, and an effective part. It is a top view of the process target in which the laser processing method of 2nd Embodiment of this invention is implemented. It is a top view of the process target in which the laser processing method of 2nd Embodiment of this invention is implemented. It is a figure which shows the example of the corner | angular part of the effective part used as the object of the laser processing method of this invention.

  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. Therefore, the formation of the modified region will be described with reference to FIGS. 1 to 6 without limiting the material of the workpiece.

  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 this laser processing apparatus 100, the laser light L emitted from the laser light source 101 has its optical axis changed by 90 ° by the dichroic mirror 103, and the inside of the processing object 1 placed on the support base 107. The light is condensed by the condensing lens 105. 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, a crack may be formed starting from the modified region 7, and the crack and modified region 7 may be exposed on the outer surface (front surface, back surface, or outer peripheral surface) of the workpiece 1.

  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.

Considering the required cutting accuracy, required flatness of the cut surface, thickness of the workpiece, type, crystal orientation, etc., the size of the modified spot and the length of the crack to be generated are appropriately determined. It is preferable to control.
[First Embodiment]

  As illustrated in FIG. 7A, the workpiece 1 is a rectangular plate-shaped member having a front surface 1 a and a back surface 1 b and includes a tempered glass plate 10. The tempered glass plate 10 is a glass plate having a tensile stress layer and a compressive stress layer formed on both sides of the tensile stress layer. The tempered glass plate 10 is formed by immersing a normal glass (float glass) plate in a molten salt and forming a compressive stress layer on the surface layer of the glass plate by ion exchange (ion exchange method) or heating a normal glass plate. Thereafter, the glass plate is rapidly cooled (air cooling strengthening method) by blowing air on the surface of the glass plate. In the tempered glass plate 10, the thickness direction thereof coincides with the arrangement direction of the tensile stress layer and the compressive stress layer.

  A plurality (four in this case) of rectangular plate-shaped effective portions 17 are cut out from the workpiece 1 configured as described above as follows. In addition, as shown in FIG.7 (b), the effective part 17 has the surface 17a and the back surface 17b, and the chamfered four corner | angular part 18, and each corner | angular part 18 has the chamfered surface 18a convex. R-chamfered so as to be a curved surface. Such an effective portion 17 is used for a protective substrate of a display of a portable terminal.

  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 placed on the support table 107 such as by sticking a tape on the back surface 1b of the processing object 1 or forming the support table 107 in a porous shape and vacuum-adsorbing the processing object 1. Hold. And with respect to the workpiece 1, the 1st scheduled cutting line 51 (one-dot chain line in Fig.7 (a)), the 2nd scheduled cutting line 52 (dashed line in Fig.7 (a)), and the 3rd scheduled cutting line 53 (FIG. 7 (a) is set.

  The first scheduled cutting line 51 extends along the side surface 19 of each effective portion 17 (that is, the four end surfaces 17c and the four chamfered surfaces 18a of each effective portion 17). The first scheduled cutting lines 51 closed in an annular shape are arranged in a plurality of rows and a plurality of columns (here, 2 rows and 2 columns) with respect to the workpiece 1. Each first scheduled cutting line 51 is separated from the side surface 1c of the workpiece 1, and the adjacent first scheduled cutting lines 51, 51 are separated from each other.

  The second scheduled cutting line 52 extends from the outside of the effective portion 17 to reach each corner portion 18. Each second scheduled cutting line 52 is continuous with the portion 51a extending along the end surface 17c of the effective portion 17 in the first scheduled cutting line 51, and along the chamfered surface 18a in the first scheduled cutting line 51. It is in contact with the extending part 51b. Since the second scheduled cutting line 52 is a line for cutting off a portion around each effective portion 17, each second scheduled cutting line 52 reaches the side surface 1c of the workpiece 1 or is scheduled to be third cut. Crosses line 53.

  The third scheduled cutting line 53 extends so as to pass between the adjacent effective portions 17 and 17. The third scheduled cutting line 53 extending so as to pass between the effective portions 17 and 17 adjacent in the row direction reaches the side surfaces 1c and 1c of the workpiece 1 facing each other in the column direction. Cross 1 The third scheduled cutting line 53 extending so as to pass between the effective portions 17 and 17 adjacent in the column direction reaches the side surfaces 1c and 1c of the workpiece 1 facing each other in the row direction. Cross 1

  Subsequently, as shown in FIG. 8A, the condensing point of the laser light L is positioned inside the tempered glass plate 10 with the surface 1 a of the workpiece 1 as the laser light incident surface, and each third cutting scheduled line The workpiece 1 is irradiated with the laser beam L along the line 53. That is, the condensing point of the laser beam L is relatively moved (scanned) along the third scheduled cutting line 53. As a result, the third modified region 73 that generates the third crack 83 extending in the thickness direction of the workpiece 1 (see FIG. 8B), along the third scheduled cutting line 53, (In the third step). At this time, with the formation of the third modified region 73 with respect to the third cutting scheduled line 53 (without applying any external force to the workpiece 1), the third crack 83 generated from the third modified region 73 is caused. The processing object 1 is made to reach the front surface 1a and the back surface 1b.

  After the third modified region 73 is formed, the condensing point of the laser beam L is located inside the tempered glass plate 10 with the surface 1a of the workpiece 1 as the laser beam incident surface, as shown in FIG. 8B. The workpiece 1 is irradiated with the laser beam L along each first scheduled cutting line 51. That is, the condensing point of the laser beam L is relatively moved (scanned) along the first scheduled cutting line 51. Thereby, the 1st modified area | region 71 which generate | occur | produces the 1st crack 81 extended in the thickness direction of the workpiece 1 (refer Fig.9 (a)), and the tempered glass board 10 along the 1st scheduled cutting line 51 is shown. (First step). At this time, with the formation of the first modified region 71 with respect to the first scheduled cutting line 51 (without applying any external force to the workpiece 1), the first crack 81 generated from the first modified region 71 is formed. The processing object 1 is made to reach the front surface 1a and the back surface 1b.

  After forming the first modified region 71, as shown in FIG. 9A, the condensing point of the laser light L is positioned inside the tempered glass plate 10 with the surface 1a of the workpiece 1 as the laser light incident surface. Then, the workpiece 1 is irradiated with the laser beam L along each second scheduled cutting line 52. That is, the condensing point of the laser beam L is relatively moved (scanned) along the second scheduled cutting line 52. Thereby, the 2nd modified area | region 72 which generate | occur | produces the 2nd crack 82 extended in the thickness direction of the workpiece 1 (refer FIG.9 (b)), and the tempered glass board 10 along the 2nd cutting plan line 52 is shown. (Second step). At this time, with the formation of the second modified region 72 with respect to the second scheduled cutting line 52 (without applying any external force to the workpiece 1), the second crack 82 generated from the second modified region 72 is formed. The processing object 1 is made to reach the front surface 1a and the back surface 1b.

  By forming the first modified region 71, the second modified region 72, and the third modified region 73 in the above order, as shown in FIG. 7B, the portion around each effective portion 17 is cut off. Then, a plurality of rectangular plate-shaped effective portions 17 are cut out. In addition, in order to relatively move the condensing point of the laser beam L along each scheduled cutting line 51, 52, 53, the processing object 1 side (the support base 107 or the like) may be moved, or the laser may be moved. The light L side (laser light source 101, dichroic mirror 103, condensing lens 105, etc.) may be moved, or both the workpiece 1 side and the laser light L side may be moved. Further, the holding of the workpiece 1 on the support base 107 is released after all the modified regions 71, 72, 73 are formed.

  As described above, in the laser processing method according to the first embodiment, the first cutting scheduled line 51 extending along the side surface 19 of the effective portion 17 (that is, the end surface 17c and the chamfered surface 18a of the effective portion 17). The first modified region 71 is formed along the second cut region 52, and then the second modified region 72 is formed along the second scheduled cutting line 52 extending from the outside of the effective portion 17 to the corner portion 18. When the first modified region 71 and the second modified region 72 are formed in this order, along the portion 51b extending along the chamfered surface 18a of the corner portion 18 in the first cutting scheduled line 51 for the following reason. Therefore, the first crack 81 can be easily extended with high accuracy. That is, since the tempered glass plate 10 includes a tensile stress layer and a compressive stress layer formed on both sides of the tensile stress layer, cracks 81 to 83 are easily generated from the modified regions 71 to 73 and are easily extended. Therefore, when the first modified region 71 is formed after the second modified region 72 is formed, a part of the first crack 81 generated from the first modified region 71 is formed in the portion 51b of the first scheduled cutting line 51. Detach from the first scheduled cutting line 51 and extend toward the second modified region 72 (extends so as to be pulled by the second crack 82), and burrs and the like are likely to occur at the corner 18. On the other hand, when the second modified region 72 is formed after the first modified region 71 is formed, a situation in which a part of the first crack 81 extends toward the second modified region 72 is prevented, The first crack 81 can easily extend along the first scheduled cutting line 51 with high accuracy. Therefore, according to the laser processing method of 1st Embodiment, the effective part 17 which has the chamfered corner | angular part 18 can be cut out from the plate-shaped process target object 1 provided with the tempered glass board 10 with sufficient precision.

  In particular, in the laser processing method according to the first embodiment, the first crack 81 is caused to reach the front surface 1a and the back surface 1b of the workpiece 1 as the first modified region 71 is formed, and the second modified region 72 is formed. Accordingly, since the second crack 82 is made to reach the front surface 1a and the back surface 1b of the workpiece 1, it is more certain that a part of the first crack 81 extends toward the second modified region 72. To be prevented.

  Further, in the laser processing method of the first embodiment, the first cutting scheduled line 51 is continuous with the portion 51 a extending along the end surface 17 c of the effective portion 17, and the first cutting planned line 51 has the corner portion 18. The second scheduled cutting line 52 is set so as to contact the portion 51b extending along the chamfered surface 18a. Thereby, also in the 2nd cutting plan line 52 for cutting off the surrounding part of the effective part 17, a part of 2nd crack 82 which generate | occur | produced from the 2nd modification | reformation area | region 72 comes off from the 2nd cutting plan line 52, and is 2nd. It is possible to suppress extension toward the one modified region 71.

  Further, in the laser processing method of the first embodiment, before forming the first modified region 71, the first machining region 53 extends along the third scheduled cutting line 53 extending so as to pass between the adjacent effective portions 17 and 17. 3 A modified region 73 is formed. As a result, in one of the adjacent effective portions 17, 17, a part of the first and second cracks 81, 82 generated from the first and second modified regions 71, 72 are the first and second scheduled cutting lines. Even if it deviates from 51 and 52 and extends toward the other of the adjacent effective portions 17 and 17, since the extension is stopped by the third modified region 73 and the third crack 81, the adjacent effective portions 17 and 17. Can be prevented from being damaged.

  In particular, in the laser processing method of the first embodiment, the third crack 83 is caused to reach the front surface 1a and the back surface 1b of the workpiece 1 as the third modified region 73 is formed. The extension of a part of the first and second cracks 81 and 82 deviating from the scheduled cutting lines 51 and 52 is more reliably stopped.

  By the way, in the laser processing method of 1st Embodiment, when moving the condensing point of the laser beam L cyclically along the 1st cutting plan line 51, the repetition frequency of the laser beam L as follows, And the relative moving speed of the condensing point of the laser beam L is adjusted. That is, in the straight portion 51a, the workpiece 1 is irradiated with the laser beam L at the repetition frequency Fa, and the focusing point is relatively moved at the relative movement speed Va. In the curved portion 51b, the repetition is repeated. The workpiece 1 is irradiated with the laser light L at a repetition frequency Fb lower than the frequency Fa, and the focusing point is relatively moved at a relative movement speed Vb lower than the relative movement speed Va. As a result, if the frequency Fa is 50 kHz and the speed Va is 500 mm / s, the pulse pitch (speed Va / frequency Fa) of the laser light L in the portion 51a is 10 μm. If the frequency Fb is 1 kHz and the speed Vb is 10 mm / s, the pulse pitch (speed Vb / frequency Fb) of the laser light L in the portion 51b is 10 μm.

  Note that the adjustment of the repetition frequency of the laser light L is realized, for example, 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. In this case, the repetition frequency of the laser light L emitted from the laser light source 101 can be reduced by thinning out the repetition frequency of the laser light L from the laser light source 101 using the AOM.

  As described above, when the first modified region 71 is formed along the curved portion 51b (that is, along the chamfered surface 18a of the effective portion 17), along the straight portion 51a (that is, along the chamfered surface 18a of the effective portion 17). Compared with the case where the first modified region 71 is formed (along the end face 17c of the effective portion 17), the relative moving speed of the condensing point of the laser light L is lowered. Thereby, the situation where the condensing point of the laser beam L passes outside the chamfered surface 18a with respect to the effective portion 17 can be prevented, and the first modified region 71 can be accurately formed along the chamfered surface 18a. it can.

  Further, when the first modified region 71 is formed along the curved portion 51b, the laser beam L is condensed compared to the case where the first modified region 71 is formed along the straight portion 51a. In addition to lowering the relative movement speed of the points, the repetition frequency of the laser light L is lowered. If the relative moving speed of the condensing point of the laser beam L is lowered without lowering the repetition frequency of the laser beam L, the pulse pitch is shortened, so that a modified spot (formed by irradiation of one pulse of the laser beam L) is formed. The first modified region 71 is formed in a state where the modified portion) is dense, and as a result, the first crack 81 may not easily extend in the thickness direction of the workpiece 1. By lowering the relative moving speed of the condensing point of the laser light L and lowering the repetition frequency of the laser light L, the pulse pitch is prevented from being shortened, and the first portion along the chamfered surface 18a of the effective portion 17 is prevented. The modified region 71 can be formed so that the first crack 81 can be easily extended.

Further, in the laser processing method of the first embodiment, the condensing point of the laser light L is relatively moved along the linearly continuous second scheduled cutting line 52 and the portion 51a of the first scheduled cutting line 51. When passing over the second scheduled cutting line 52, the irradiation of the laser beam L with respect to the workpiece 1 is turned ON, and when passing over the portion 51a of the first scheduled cutting line 51, the laser beam L with respect to the workpiece 1 is turned on. Is turned off. This prevents the laser beam L from being irradiated again to the first modified region 71 and the first crack 81 that have already been formed along the portion 51a of the first scheduled cutting line 51. Therefore, it is possible to prevent the cutting quality of the end surface 17c of the effective portion 17 corresponding to the portion 51a of the first cutting scheduled line 51 from being lowered or the bending strength of the effective portion 17 from being lowered. Note that ON / OFF switching of the irradiation of the laser beam L to the workpiece 1 is also realized by an optical element such as the above-described ultrasonic light modulator (AOM).
[Second Embodiment]

  The laser processing method of the second embodiment is mainly different from the laser processing method of the first embodiment described above in that the third cutting scheduled line 53 is not set for the workpiece 1. In the laser processing method of the second embodiment, first, as shown in FIG. 10 (a), the first cutting scheduled line 51 (the one-dot chain line in FIG. 10 (a)) and the second cutting scheduled are performed on the workpiece 1. A line 52 (broken line in FIG. 10A) is set.

  The first scheduled cutting line 51 extends along the side surface 19 of each effective portion 17 (that is, the four end surfaces 17c and the four chamfered surfaces 18a of each effective portion 17). The first scheduled cutting lines 51 closed in an annular shape are arranged in a plurality of rows and a plurality of columns (here, 2 rows and 2 columns) with respect to the workpiece 1. Each first scheduled cutting line 51 is separated from the side surface 1c of the workpiece 1 and the adjacent first scheduled cutting lines 51, 51 are sufficiently large (for example, more than the width of the effective portion 17 in plan view). ) Separated.

  The second scheduled cutting line 52 extends from the outside of the effective portion 17 to reach each corner portion 18. Each second scheduled cutting line 52 is continuous with the portion 51a extending along the end surface 17c of the effective portion 17 in the first scheduled cutting line 51, and along the chamfered surface 18a in the first scheduled cutting line 51. It is in contact with the extending part 51b. Since the second scheduled cutting line 52 is a line for cutting off a portion around each effective portion 17, each second scheduled cutting line 52 reaches the side surface 1 c of the workpiece 1.

  Subsequently, as shown in FIG. 11, the condensing point of the laser light L is positioned inside the tempered glass plate 10 with the surface 1 a of the workpiece 1 as the laser light incident surface, and along each first scheduled cutting line 51. Then, the workpiece 1 is irradiated with the laser beam L. That is, the condensing point of the laser beam L is relatively moved (scanned) along the first scheduled cutting line 51. Thereby, the 1st modified area | region 71 which generate | occur | produces the 1st crack 81 extended in the thickness direction of the workpiece 1 (refer Fig.12 (a)), and the tempered glass board 10 along the 1st scheduled cutting line 51 is shown. (First step). At this time, with the formation of the first modified region 71 with respect to the first scheduled cutting line 51 (without applying any external force to the workpiece 1), the first crack 81 generated from the first modified region 71 is formed. The processing object 1 is made to reach the front surface 1a and the back surface 1b.

  After forming the first modified region 71, as shown in FIG. 12A, the condensing point of the laser light L is located inside the tempered glass plate 10 with the surface 1a of the workpiece 1 as the laser light incident surface. Then, the workpiece 1 is irradiated with the laser beam L along each second scheduled cutting line 52. That is, the condensing point of the laser beam L is relatively moved (scanned) along the second scheduled cutting line 52. Thereby, the 2nd modified area | region 72 which generate | occur | produces the 2nd crack 82 extended in the thickness direction of the workpiece 1 (refer FIG.12 (b)), and the tempered glass board 10 along the 2nd cutting plan line 52 is shown. (Second step). At this time, with the formation of the second modified region 72 with respect to the second scheduled cutting line 52 (without applying any external force to the workpiece 1), the second crack 82 generated from the second modified region 72 is formed. The processing object 1 is made to reach the front surface 1a and the back surface 1b.

  By forming the first modified region 71 and the second modified region 72 in the above order, as shown in FIG. 10 (b), the portion around each effective portion 17 is cut off, and the rectangular plate-shaped effective A plurality of parts 17 are cut out. In addition, in order to relatively move the condensing point of the laser beam L along each scheduled cutting line 51, 52, the workpiece 1 side may be moved, or the laser beam L side may be moved. Alternatively, both the workpiece 1 side and the laser beam L side may be moved. Further, the holding of the workpiece 1 on the support base 107 is released after all the modified regions 71 and 72 are formed.

  As described above, in the laser processing method according to the second embodiment, the first cutting scheduled line 51 extending along the side surface 19 of the effective portion 17 (that is, the end surface 17c and the chamfered surface 18a of the effective portion 17). The first modified region 71 is formed along the second cut region 52, and then the second modified region 72 is formed along the second scheduled cutting line 52 extending from the outside of the effective portion 17 to the corner portion 18. Therefore, according to the laser processing method of the second embodiment, the same effects as those of the laser processing method of the first embodiment are exhibited.

  Further, in the laser processing method of the second embodiment, the adjacent first cutting scheduled lines 51 and 51 are sufficiently separated from each other (for example, more than the width of the effective portion 17 in plan view). As a result, in one of the adjacent effective portions 17, 17, a part of the first and second cracks 81, 82 generated from the first and second modified regions 71, 72 are the first and second scheduled cutting lines. Even if it deviates from 51 and 52 and extends toward the other of the adjacent effective portions 17 and 17, it is difficult to reach the other of the adjacent effective portions 17 and 17. Damage can be prevented.

  Although the first and second embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, the shapes of the processing object and the effective portion are not limited to a rectangular plate shape, and various shapes can be applied. Moreover, you may cut out one effective part from a process target object.

  In addition, 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, the crack which generate | occur | produced from the modification | reformation area | region with the formation of the modification | reformation area | region with respect to each cutting planned line (without applying any external force to a process target object) on the surface and back surface of a process target object. Although it was made to reach, it is not limited to this. In other words, only the crack is generated along with the formation of the modified region, and the crack may reach only one of the front surface and the back surface of the workpiece, or both the front and back surfaces of the workpiece are processed. It is not necessary to let the crack reach. In these cases, after forming the modified region, an external force is applied along the planned cutting line to cause the cracks generated from the modified region to reach the front and back surfaces of the workpiece, thereby cutting. What is necessary is just to cut | disconnect a process target object along a line.

  Moreover, as shown in FIG. 13, the corner | angular part 18 of the effective part 17 may be comprised from the chamfering surface 18a which is one or several substantially planes. Even in those cases, according to the present invention, it is possible to prevent the crack from extending from the chamfered surface in an unnecessary direction, and to accurately cut out the effective portion having the chamfered corner portion from the plate-like workpiece. it can.

  Further, the object to be processed may be one in which a resin film or the like is formed on at least one of the front surface and the back surface of the tempered glass plate. In addition, as the modified region, a melt-processed region, a crack region, a dielectric breakdown region, a refractive index change region, or a region in which these are mixed is formed depending on the irradiation condition of the laser beam.

  DESCRIPTION OF SYMBOLS 1 ... Processing target object, 1a ... Front surface, 1b ... Back surface, 10 ... Tempered glass plate, 17 ... Effective part, 17c ... End surface, 18 ... Corner | angular part, 18a ... Chamfering surface, 19 ... Side surface, 51 ... 1st scheduled cutting line 52 ... second cutting scheduled line, 53 ... third cutting scheduled line, 71 ... first modified region, 72 ... second modified region, 73 ... third modified region, 81 ... first crack, 82 ... first 2 cracks, 83... Third crack, L... Laser light, P.

Claims (6)

A laser processing method for cutting out an effective portion having a chamfered corner from a plate-like processing object including a tempered glass plate,
A laser beam condensing point is relatively moved along a first scheduled cutting line extending along at least the chamfered surface of the corner, thereby extending in the thickness direction of the workpiece. A first step of forming a first modified region for generating one crack in the tempered glass plate along the first scheduled cutting line;
After the first step, the processing target is moved by relatively moving a condensing point of the laser light along a second scheduled cutting line extending from the outside of the effective portion to the corner portion. And a second step of forming a second modified region for generating a second crack extending in the thickness direction of the object inside the tempered glass plate along the second scheduled cutting line. . In the first step, the first crack reaches the front surface and the back surface of the workpiece,
The laser processing method according to claim 1, wherein in the second step, the second crack is caused to reach the front surface and the back surface of the workpiece.   When the first scheduled cutting line extends along the end surface of the effective portion that reaches the chamfered surface of the side surface of the effective portion, the first cutting planned line extends along the end surface in the first planned cutting line. The laser processing method according to claim 1, wherein the second scheduled cutting line is set so as to be continuous with an existing portion.   When the chamfered surface is a convex curved surface, the second planned cutting line is set so as to contact a portion extending along the chamfered surface in the first planned cutting line. The laser processing method according to any one of claims.   In the case where a plurality of effective portions are cut out from the object to be processed, laser light is collected along a third scheduled cutting line extending so as to pass between adjacent effective portions before the first step. A third modified region that generates a third crack that extends in the thickness direction of the workpiece by moving the light spot relatively is formed inside the tempered glass plate along the third scheduled cutting line. The laser processing method according to any one of claims 1 to 4, further comprising a third step of forming the step.   The laser processing method according to claim 5, wherein in the third step, the third crack reaches the front surface and the back surface of the processing object.

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