Laser processing apparatus and laser processing method

Abstract

To provide a laser processing device and a laser processing method capable of suppressing deterioration in processing quality.SOLUTION: A control unit 6 tilts a longitudinal direction NH of a condensing area C of a laser beam L to be away from a (111) plane K3 with respect to a processing progress direction ND when irradiating a first area A1 of a line A with the laser beam L, and the longitudinal direction NH of the condensing area C of the laser beam L is tilted away from a (111) plane K4 with respect to the processing progress direction ND when irradiating a second area A2 of the line A with the laser beam L.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a laser processing apparatus and a laser processing method. [Background Art]

[0002] Patent Document 1 describes a laser processing method for an object (a silicon wafer as an example) having a (100) plane as a main surface. In this laser processing method, a modified region is formed by irradiating the object with laser light while relatively moving a condensing region of the laser light along an annularly extending line. In particular, the object has a first crystal orientation perpendicular to one (110) plane and a second crystal orientation perpendicular to another (110) plane. Then, during processing, the longitudinal direction of the condensing region of the laser light is adjusted in each region of the line according to the positional relationship with the first crystal orientation and the second crystal orientation. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2020-069530 [Summary of Invention] [Problem to be Solved by the Invention]

[0004] According to the laser processing method described in Patent Document 1, when processing an object having a (100) plane as a main surface as described above, the condensing region of the laser light is adjusted according to the crystal structure of the object, thereby suppressing deterioration in quality of the processed surface (cut surface) of the object.

[0005] Incidentally, in recent years, as an object to be processed by irradiating with laser light to form a modified region (and further cutting along the modified region), the crystal orientation with the (110) plane as the surface has been used. <110> The use of wafers is being considered. In this case, the (110) plane, which is the surface of the object, is considered the incident surface of the laser beam. For such objects, the relationship between the line that moves the laser beam focusing region and the crystal orientation is different from that of the object described in Patent Document 1. Therefore, it is desirable to suppress the deterioration of the processing quality of the object by performing a separate, more appropriate processing.

[0006] This disclosure aims to provide a laser processing apparatus and a laser processing method capable of suppressing a decrease in processing quality. [Means for solving the problem]

[0007] The laser processing apparatus according to this disclosure comprises: [1] a support unit for supporting an object; an irradiation unit for irradiating the object supported by the support unit with laser light; a moving unit for moving the focusing area of ​​the laser light relative to the object; and a control unit for controlling the moving unit and the irradiation unit, wherein the object includes a main surface which is a (110) surface, a (100) surface, and a (111) surface, and is supported by the support unit such that the (110) surface becomes the incident surface of the laser light, and the object has a surface which intersects the incident surface. Viewed from the Z direction, an annular line is set to intersect another (110) surface, the (100) surface, and the (111) surface, which is the main surface (110) surface, and when viewed from the Z direction, the intersection points of the line with the other (110) surface are set to 0° and 180°, the intersection point with the (100) surface is set to 90°, the point of contact with one of the (111) surfaces is set to 55°, and the point of contact with another (111) surface that intersects the first (111) surface is set to 125°, the first line includes a point of 35° between 0° and 60°. The laser processing apparatus includes a first region and a second region including 145° between 120° and 180°, wherein the irradiation unit has a forming unit that shapes the laser beam such that the focusing region has a longitudinal direction when viewed from the Z direction, the control unit controls the irradiation unit and the moving unit to move the focusing region relative to the line, thereby performing a processing operation to irradiate the object along the line with the laser beam to form a modified region, the control unit controls the irradiation unit and the moving unit to move the focusing region relative to the line, the control unit controls the forming unit to shape the laser beam so that the longitudinal direction is tilted away from the first (111) plane with respect to the processing direction which is the relative movement direction of the focusing region, and the control unit controls the forming unit to shape the laser beam so that the longitudinal direction is tilted away from the other (111) plane with respect to the processing direction.

[0008] The workpiece of this laser processing apparatus has a (110) plane as its main surface, which is the incident surface of the laser beam. An annular line is set up so as to intersect the (110), (100), and (111) planes that intersect the main surface when viewed from the Z direction intersecting the incident surface. The line also includes a first region containing a point at 35° between 0° and 60°, where the intersection points with the (110) plane are 0° and 180°, the intersection point with the (100) plane is 90°, the point of contact with one (111) plane is 55°, and the point of contact with another (111) plane intersecting one (111) plane is 125°, and a second region containing a point at 145° between 120° and 180°. When irradiating the first region of the line with laser light, the longitudinal direction of the laser light focusing region is tilted away from one (111) plane with respect to the processing direction. Similarly, when irradiating the second region of the line with laser light, the longitudinal direction of the laser light focusing region is tilted away from another (111) plane with respect to the processing direction. In this way, the deterioration of processing quality is suppressed at 35° and 145°, where quality deterioration tends to be significant. Therefore, this laser processing apparatus can suppress the deterioration of processing quality for objects having the above-described relationship between the line and crystal orientation.

[0009] The laser processing apparatus according to this disclosure may also be [2] "the laser processing apparatus according to [1] above, wherein the control unit makes the processing direction in the first region and the processing direction in the second region the same in the processing process." In this case, there is no need to change the processing direction between processing in the first region and processing in the second region, and the processing time is shortened.

[0010] The laser processing apparatus according to the present disclosure may also be [3] "the laser processing apparatus according to [1] or [2] above, wherein the line includes a third region including 75° between 50° and 90°, and a fourth region including 105° between 90° and 130°, and the control unit, in the processing process, when irradiating the third region of the line with laser light, controls the forming unit to shape the laser light so that the longitudinal direction is tilted away from the first (111) plane with respect to the processing direction, and the control unit, in the processing process, when irradiating the fourth region of the line with laser light, controls the forming unit to shape the laser light so that the longitudinal direction is tilted away from the other (111) plane with respect to the processing direction." In this case, the deterioration of processing quality can be suppressed even in the 75° and 105° sections of the line, where quality deterioration tends to be somewhat more pronounced.

[0011] The laser processing apparatus according to this disclosure may also be [4] "the laser processing apparatus according to [3] above, wherein the control unit controls the molding unit in the processing process to make the inclination angle of the longitudinal direction with respect to the processing progress direction when the laser light is irradiated onto the first and second regions greater than the inclination angle of the longitudinal direction with respect to the processing progress direction when the laser light is irradiated onto the third and fourth regions." In this case, the deterioration of processing quality can be suppressed more appropriately in each of the first and second regions and the third and fourth regions.

[0012] The laser processing apparatus according to the present disclosure may also be [5] "the laser processing apparatus according to [3] or [4] above, wherein the control unit performs irradiation of the laser beam in the first region and irradiation of the laser beam in the fourth region in the processing process, and then performs irradiation of the laser beam in the second region and irradiation of the laser beam in the third region." In this case, the processing of regions in each region of the line where the longitudinal inclination of the laser beam focusing region is in the same direction is performed together, thereby facilitating control of the molding section.

[0013] The laser processing apparatus according to this disclosure may be [6] "the laser processing apparatus according to any of [3] to [5] above, wherein the first region is a region extending from 0° to 55°, the third region is a region extending from 55° to 90° and has a boundary with the first region, the fourth region is a region extending from 90° to 125° and has a boundary with the third region, and the second region is a region extending from 125° to 180° and has a boundary with the fourth region." In this case, the region between 0° and 180° of the line is composed of two types of regions (first and third regions and second and fourth regions) in which the longitudinal inclination direction of the laser beam focusing region is different from each other. Therefore, the number of times conditions are switched (for example, twice) when processing these regions is reduced, and the processing time can be shortened.

[0014] The laser processing apparatus according to this disclosure may be [7] "the laser processing apparatus according to any of [3] to [5] above, wherein the first region is a region extending from 0° to 60°, the third region is a region extending from 60° to 90° and has a boundary with the first region, the fourth region is a region extending from 90° to 120° and has a boundary with the third region, and the second region is a region extending from 120° to 180° and has a boundary with the fourth region." In this way, it is possible to provide a certain margin at the boundary of each region constituting the line in case of a decrease in processing quality.

[0015] The laser processing apparatus according to the present disclosure may be [8] "the laser processing apparatus according to any of [1] to [7] above, wherein the first region includes a first portion including 35° and a first front portion on the 0° side of the first portion, the second region includes a second portion including 145° and a second rear portion on the 180° side of the second portion, and the control unit controls the forming section in the processing process to make the inclination angle of the longitudinal direction with respect to the processing progress direction when the laser light is irradiated onto the first portion and the second portion greater than the inclination angle of the longitudinal direction with respect to the processing progress direction when the laser light is irradiated onto the first front portion and the second rear portion." In this case, when processing at 35° and 145°, where deterioration of processing quality in the first and second regions tends to be significant, the deterioration of processing quality can be reliably suppressed by relatively increasing the inclination angle of the longitudinal direction of the laser light focusing area. Furthermore, when processing areas where the deterioration of processing quality is not particularly significant, such as the part closer to 0° in the first region or the part closer to 180° in the second region, it is possible to suppress the deterioration of processing quality due to the influence of the longitudinal inclination of the laser beam's focusing region by relatively reducing the longitudinal inclination of the laser beam's focusing region.

[0016] The laser processing apparatus according to the present disclosure may be [9] "the laser processing apparatus according to any of [3] to [5] above, wherein the first region is a part of the region between 0° and 60°, the third region is a part of the region between 60° and 90°, the fourth region is a part of the region between 90° and 120°, the second region is a part of the region between 120° and 180°, and the control unit controls the forming section in the processing process so that when the laser beam is irradiated to regions other than the first region, second region, third region, and fourth region between 0° and 180° of the line, the longitudinal direction is not tilted with respect to the processing direction." In this case, by not tilting the longitudinal direction of the laser beam focusing region in regions other than those containing a portion of the line where the deterioration of processing quality is particularly pronounced, it is possible to suppress the deterioration of processing quality due to the influence of the tilt of the longitudinal direction of the laser beam focusing region when processing regions where the deterioration of processing quality is relatively not pronounced.

[0017] The laser processing apparatus according to the present disclosure includes:

[10] "The first region includes a first portion including 35°, a first front portion on the 0° side of the first portion, and a first rear portion on the 60° side of the first portion; the second region includes a second portion including 145°, a second front portion on the 120° side of the second portion, and a second rear portion on the 180° side of the second portion; and the control unit controls the forming section in the processing process to determine the angle of inclination of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first front portion, and the angle of inclination of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first portion." The laser processing apparatus may be any of the above [1] to [7], wherein the angle of inclination of the longitudinal direction with respect to the processing direction when the laser beam is irradiated onto the first rear portion increases in this order, and the control unit controls the molding section in the processing process so that the angle of inclination of the longitudinal direction with respect to the processing direction when the laser beam is irradiated onto the second rear portion, the angle of inclination of the longitudinal direction with respect to the processing direction when the laser beam is irradiated onto the second portion, and the angle of inclination of the longitudinal direction with respect to the processing direction when the laser beam is irradiated onto the second front portion increases in this order.

[0018] The laser processing method according to the present disclosure is a laser processing method comprising a processing step of irradiating an object with laser light while relatively moving a focusing region of laser light relative to the object, wherein the focusing region is relatively moved along a line set on the object, thereby irradiating the object with laser light along the line to form a modified region, the object includes a main surface which is a (110) surface, a (100) surface, and a (111) surface, the (110) surface is supported so as to be the incident surface of the laser light, the line is set in an annular shape so as to intersect another (110) surface which is the main surface which is the (110) surface, the (100) surface, and the (111) surface when viewed from the Z direction intersecting the incident surface, the line has intersections with the other (110) surface at 0° and 180° when viewed from the Z direction, and the intersection with the (100) surface at 90° The laser processing method includes a first region including a point at 35° between 0° and 60°, and a second region including 145° between 120° and 180°, wherein when the laser beam is irradiated onto the first region of the line, the laser beam is shaped so that the focusing region has a longitudinal direction, and the longitudinal direction is tilted away from the first region of the line with respect to the processing direction, which is the relative movement direction of the focusing region, and when the laser beam is irradiated onto the second region of the line, the laser beam is shaped so that the focusing region has a longitudinal direction, and the longitudinal direction is tilted away from the other region of the line with respect to the processing direction, which is the relative movement direction of the focusing region.

[0019] This laser processing method, like the laser processing apparatus described above, makes it possible to suppress the deterioration of processing quality. [Effects of the Invention]

[0020] According to this disclosure, it is possible to provide a laser processing apparatus and a laser processing method that can suppress a decrease in processing quality. [Brief explanation of the drawing]

[0021] [Figure 1] Fig. 1 is a schematic diagram illustrating the configuration of a laser processing apparatus according to one embodiment. [Figure 2] Fig. 2 is a schematic diagram illustrating the configuration of an irradiation unit shown in Fig. 1. [Figure 3] Fig. 3 is a diagram showing an object of laser processing according to the present embodiment. [Figure 4] Fig. 4 is a cross-sectional view of the object shown in Fig. 3. [Figure 5] Fig. 5 is a plan view of the object shown in Figs. 3 and 4. [Figure 6] Fig. 6 is a plan view of the object shown in Figs. 3 and 4. [Figure 7] Fig. 7 is a diagram illustrating a processing process according to the present embodiment, wherein (a) of Fig. 7 is a plan view and (b) of Fig. 7 is a side view. [Figure 8] Fig. 8 is a diagram showing an example of the shape of a converged region of laser light in the processing process, wherein (a) of Fig. 8 shows shape QB and (b) of Fig. 8 shows another shape QA. [Figure 9] Fig. 9 is a diagram illustrating switching of the shape of a converged region during the processing process. [Figure 10] Fig. 10 is a diagram showing the object in a state where the processing process is completed, wherein (a) of Fig. 10 is a plan view and (b) of Fig. 10 is a side view. [Figure 11] Fig. 11 is an enlarged cross-sectional view showing a part of the object shown in Fig. 10. [Figure 12] Fig. 12 is a diagram showing the shape of the converged region in an XY plane. [Figure 13] Fig. 13 is photographs showing cut surfaces of the object at each processing angle on a line. [Figure 14] Fig. 14 is a photograph of a cut surface of the object showing a processing result at a processing angle of 35°. [Figure 15] Fig. 15 is a photograph of a cut surface of the object showing a processing result at a processing angle of 35°. [Figure 16]Figure 16 is a schematic diagram showing the processing steps involved in the modified example. [Figure 17] Figure 17 is a schematic diagram showing the processing steps related to another modified example. [Figure 18] Figure 18 is a schematic diagram showing the processing of yet another modified example. [Figure 19] Figure 19 is a schematic diagram showing the processing of yet another modified example. [Modes for carrying out the invention]

[0022] An embodiment will be described below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals, and redundant explanations may be omitted. In addition, each drawing may show a Cartesian coordinate system defined by the X, Y, and Z axes.

[0023] Figure 1 is a schematic diagram showing the configuration of a laser processing apparatus according to one embodiment. As shown in Figure 1, the laser processing apparatus 1 comprises a stage (support unit) 2, an irradiation unit 3, moving units 4 and 5, and a control unit 6. The laser processing apparatus 1 is a device for forming a modified region 12 on an object 11 by irradiating the object 11 with laser light L.

[0024] Stage 2 supports the object 11, for example, by holding a film attached to the object 11. Stage 2 is rotatable about an axis parallel to the Z direction. Stage 2 may also be movable along the X and Y directions. The X and Y directions are the first and second horizontal directions, which intersect (are orthogonal to each other), and the Z direction is the vertical direction.

[0025] The irradiation unit 3 is for irradiating the object 11 supported on the stage 2 with laser light L. The irradiation unit 3 focuses laser light L, which is penetrating to the object 11, and irradiates the object 11 with it. When the laser light L is focused inside the object 11 supported on the stage 2, the laser light L is particularly absorbed in the portion corresponding to the focusing region C of the laser light L (for example, the center Ca shown in Figure 12), and a modified region 12 is formed inside the object 11. The focusing region C is a predetermined range from the position where the beam intensity of the laser light L is highest or the centroid of the beam intensity.

[0026] The modified region 12 is a region whose density, refractive index, mechanical strength, and other physical properties differ from those of the surrounding unmodified region. Examples of modified regions 12 include melted regions, cracked regions, dielectric breakdown regions, and refractive index change regions. The modified region 12 may be formed such that cracks extend from the modified region 12 toward the incident side of the laser beam L and the opposite side. Such modified regions 12 and cracks can be used, for example, to cut an object 11.

[0027] For example, when Stage 2 is moved along the X direction, and the focusing region C is moved relative to the object 11 along the X direction, multiple modified spots 12s are formed in a line along the X direction. Each modified spot 12s is formed by irradiation with one pulse of laser light L. A line of modified regions 12 is a collection of multiple modified spots 12s arranged in a line. Adjacent modified spots 12s may be connected to each other or separated from each other, depending on the relative movement speed of the focusing region C with respect to the object 11 and the repetition frequency of the laser light L.

[0028] The moving unit 4 includes a first moving unit 41 that moves the stage 2 in one direction within a plane intersecting (orthogonal to) the Z direction, and a second moving unit 42 that moves the stage 2 in another direction within the plane intersecting (orthogonal to) the Z direction. For example, the first moving unit 41 moves the stage 2 along the X direction, and the second moving unit 42 moves the stage 2 along the Y direction. The moving unit 4 also rotates the stage 2 around an axis parallel to the Z direction. The moving unit 5 supports the irradiation unit 3. The moving unit 5 moves the irradiation unit 3 along the X, Y, and Z directions. When the stage 2 and / or the irradiation unit 3 are moved while the focused area C of the laser beam L is formed, the focused area C is moved relative to the object 11. That is, the moving units 4 and 5 move at least one of the stage 2 and the irradiation unit 3 in order to move the focused area C of the laser beam L relative to the object 11.

[0029] The control unit 6 controls the operation of the stage 2, the irradiation unit 3, and the moving units 4 and 5. The control unit 6 has a processing unit, a storage unit, and an input receiving unit (not shown). The processing unit is configured as a computer device including a processor, memory, storage, and communication devices. In the processing unit, the processor executes software (programs) loaded into memory, etc., and controls the reading and writing of data in memory and storage, as well as communication by the communication devices. The storage unit is, for example, a hard disk, and stores various types of data. The input receiving unit is an interface unit that displays various types of information and accepts input of various types of information from the user. The input receiving unit constitutes a GUI (Graphical User Interface).

[0030] Figure 2 is a schematic diagram showing the configuration of the irradiation unit shown in Figure 1. Figure 2 shows a hypothetical line A indicating the planned laser processing. As shown in Figure 2, the irradiation unit 3 includes a light source 31, a spatial light modulator (shaping unit) 7, a focusing lens 33, and a 4f lens unit 34. The light source 31 outputs laser light L, for example, by a pulse oscillation method. The irradiation unit 3 may also be configured to not have a light source 31, and to introduce laser light L from outside the irradiation unit 3. The spatial light modulator 7 modulates the laser light L output from the light source 31. The focusing lens 33 focuses the laser light L, which has been modulated by the spatial light modulator 7 and output from the spatial light modulator 7, toward the object 11.

[0031] In the spatial light modulator 7, when a signal indicating a modulation pattern is input from the control unit 6, the modulation pattern is displayed according to the signal. The modulation pattern is for modulating the laser light L. In the spatial light modulator 7, when the modulation pattern is displayed and the laser light L is incident from the outside, reflected, and emitted to the outside, the laser light L is modulated according to the displayed modulation pattern. In this way, the spatial light modulator 7 makes it possible to modulate the laser light L (for example, modulating the intensity, amplitude, phase, polarization, etc. of the laser light L) by appropriately setting the displayed modulation pattern.

[0032] As described above, the laser light L output from the light source 31 is incident on the focusing lens 33 via the spatial light modulator 7 and the 4f lens unit 34, and is focused into the object 11 by the focusing lens 33, thereby forming a modified region 12 and cracks extending from the modified region 12 in the object 11 within the focused region C. Furthermore, by controlling the movement units 4 and 5 of the control unit 6, the focused region C is moved relative to the object 11, thereby forming the modified region 12 and cracks along the direction of movement of the focused region C.

[0033] Figure 3 shows an object to be laser processed according to this embodiment. Figure 3(a) is a plan view, and Figure 3(b) is a side view. Figure 4 is a cross-sectional view of the object shown in Figure 3. As shown in Figures 3 and 4, the object 100 includes the object 11 described above and an object 11R which is a separate component from object 11. Object 11R is, for example, a silicon wafer. Object 11 includes a plurality of functional elements and includes a device layer 110 formed on the second surface 11b. Object 11R includes a plurality of functional elements and includes a device layer 110R formed on the first surface 11Ra of object 11R. Object 11 and object 11R are bonded together by arranging the device layer 110 and the device layer 110R so that they face each other and joining them, thereby constituting the object 100.

[0034] The object 11 includes an effective region R and a removal region E. The effective region R is the portion corresponding to the semiconductor device to be acquired. Here, the effective region R is a disc-shaped portion including the central part of the object 11 when viewed from the Z direction, which is the thickness direction of the object 11. The removal region E is the region of the object 11 outside of the effective region R. The removal region E is the outer edge portion of the object 11 other than the effective region R. Here, the removal region E is the annular portion surrounding the effective region R. Here, a modified region 12 and cracks extending from the modified region 12 are formed in the object 11, and trimming is performed to cut off the removal region E of the object 11 using the modified region 12 and cracks as boundaries. Therefore, an annular line A is set on the object 11 at the boundary between the removal region E and the effective region R, where laser light L is to be irradiated.

[0035] As shown in Figure 4, the object 11 includes a first part 15A and a second part 15B arranged sequentially along the Z direction from the second surface 11b (opposite surface) opposite to the first surface (main surface) 11a, which is the incident surface of the laser beam L. In the first part 15A, a modified region 12 is formed to create a crack extending obliquely with respect to the Z direction (hereinafter sometimes referred to as an "oblique crack"), and in the second part 15B, a modified region 12 is formed to create a crack extending along the Z direction (hereinafter sometimes referred to as a "vertical crack"). In Figure 4, line R1 indicates the line where an oblique crack is planned to be formed in the cross-section along the Z direction, and line R2 indicates the line where a vertical crack is planned to be formed in the cross-section along the Z direction.

[0036] Figure 5 is a plan view of the object shown in Figures 3 and 4. The object 11 shown in Figure 5 has a crystal orientation. <110> The object is a wafer (for example, a silicon wafer). That is, in object 11, the first surface 11a (main surface) is the (110) surface. Object 11 is supported on stage 2 such that the first surface 11a is the incident surface of the laser beam L. Object 11, when viewed from the Z direction intersecting (orthogonal to) the first surface 11a, includes the (110) surface K1, the (100) surface K2, the (111) surface K3, and the (111) surface K4 intersecting the (111) surface K3. The (110) surface K1 is the (110) surface that intersects (orthogonal to) the first surface 11a. The angle θ between the (100) surface K2 and the (111) surface K3 is approximately 54.7° (hereinafter referred to as 55°), and the angle φ between the (110) surface K1 and the (111) surface K3 is approximately 35.3°. Furthermore, a notch 11n is formed on the (100) surface of object 11.

[0037] As shown in Figure 6, the annular line A set on the object 11 includes intersections P1a and P1b with the (110) surface K1, intersections P2a and P2b with the (100) surface K2, contact points P3a and P3b with the (111) surface K3, and contact points P4a and P4b with the (111) surface K4. Hereafter, the machining angles on line A will be 0° for intersection P1a, 55° for contact point P3a, 90° for intersection P2a, 125° for contact point P4a, 180° for intersection P1b, 235° for contact point P3b, 270° for intersection P2b, and 305° for contact point P4b.

[0038] In this case, line A includes a first region A1 containing the point at 35° between 0° and 55°, a second region A2 containing 145° between 125° and 180°, a third region A3 containing 75° between 55° and 90°, and a fourth region A4 containing 105° between 90° and 125°. Here, the first region A1 is the region from 0° to 55°, the third region A3 is the region from 55° to 90° and has a boundary with the first region A1, the fourth region A4 is the region from 90° to 125° and has a boundary with the third region A3, and the second region A2 is the region from 125° to 180° and has a boundary with the fourth region A4.

[0039] Furthermore, the crystal orientation of object 11 is symmetrical with respect to a 180° rotation around the axis of rotation along the Z direction. Therefore, line A has the first region A5, the third region A7, the fourth region A8, and the second region A6 in the range from 180° to 360° (0°), just as it does from 0° to 180°. However, below, we will mainly describe each region between 0° and 180°.

[0040] As shown in Figure 7, the laser processing apparatus 1 irradiates the object 11 with laser light L along the line A described above. That is, in the laser processing apparatus 1, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 to move the focusing area C of the laser light L relative to line A, thereby irradiating the object 11 with laser light L along line A to perform a processing operation that forms a modified area 12 (and cracks). The processing operation in the laser processing apparatus 1 is a processing step of the laser processing method according to this embodiment.

[0041] As an example, in the processing step (processing steps (hereinafter the same)), with the focusing region C of the laser beam L positioned inside the object 11, the object 11 is rotated around a rotation axis along the Z direction in accordance with the rotation of the stage 2. This allows the laser beam L to be irradiated onto the object 11 while the focusing region C moves relative to the object along the annular line A. The relative movement direction of the focusing region C at this time (tangential direction to line A, which in this case is the X direction) is defined as the processing progress direction ND. In the processing step, the laser beam L is irradiated onto each region of line A, and the focusing region C of the laser beam L is controlled in each region of line A.

[0042] More specifically, as shown in Figure 8, the control unit 6, in the processing stage, controls the spatial light modulator 7 to shape the focusing region C in a plane intersecting the Z direction into an elongated shape (in this case, an elongated ellipse) so that when viewed from the Z direction, the focusing region C has a longitudinal direction NH. To make the focusing region C elongated, for example, the modulation pattern displayed on the spatial light modulator 7 can be made to include an astigmatism pattern for imparting astigmatism to the laser beam L. When using an astigmatism pattern, two focusing regions C are formed in the Z direction, but here, the shape of the one of the two focusing regions C closer to the incident surface of the laser beam L is made elongated. It should be noted that the shape of the focusing region C can also be made elongated by various other patterns, and any pattern can be selected, not limited to the astigmatism pattern.

[0043] In the processing, the longitudinal direction NH of the elongated focusing region C is further tilted with respect to the processing direction ND. Specifically, when the control unit 6 irradiates the first region A1 of line A with laser light during the processing, it controls the spatial light modulator 7 to shape the laser light L, thereby tilting the longitudinal direction NH away from the (111) plane K3 with respect to the processing direction ND (see Figure 8(a)). Also, when the control unit 6 irradiates the fourth region A4 of line A with laser light during the processing, it controls the spatial light modulator 7 to shape the laser light L, thereby tilting the longitudinal direction NH away from the (111) plane K4 with respect to the processing direction ND (see Figure 8(a)). In this way, when the longitudinal direction NH is tilted away from the (111) planes K3 and K4, if the tilt direction NHa of the longitudinal direction NH is on one side of the processing direction ND (in this case, the right side), the shape of the focusing region C is referred to as shape QB. The same applies to the first region A5 and the fourth region A8.

[0044] The reason for setting the shape of the laser beam L's focusing region C to shape QB during processing of the first region A1 and the fourth region A4 is as follows: When viewed from the Z direction, during laser processing near 35° and 105° on line A, cracks extending from the modified region 12 are pulled in the direction of the nearest (111) planes K3 and K4, which tends to increase the meandering of the cut surface and worsen the processing quality. In contrast, when processing near 35° and 105°, by tilting the longitudinal direction NH of the focusing region C away from the (111) planes K3 and K4, the increase in the meandering of the cut surface is suppressed, and the deterioration of processing quality is suppressed. For this reason, during processing, the shape of the laser beam L's focusing region C is set to shape QB during processing of the first region A1 and the fourth region A4.

[0045] On the other hand, when the control unit 6 irradiates the second region A2 of line A with laser light L during the processing, it controls the spatial light modulator 7 to shape the laser light L, thereby tilting the longitudinal direction NH away from the (111) plane K4 with respect to the processing direction ND (see Figure 8(b)). Also, when the control unit 6 irradiates the third region A3 of line A with laser light L during the processing, it controls the spatial light modulator 7 to shape the laser light L, thereby tilting the longitudinal direction NH away from the (111) plane K3 with respect to the processing direction ND (see Figure 8(b)). When the longitudinal direction NH is tilted away from the (111) planes K4 and K3 in this way, if the tilt direction NHa of the longitudinal direction NH is on the other side of the processing direction ND (in this case, the left side), the shape of the focusing region C is referred to as shape QA. The same applies to the second region A6 and the third region A7.

[0046] The reason for setting the shape of the laser beam L's focusing region C to shape QA during processing of the second region A2 and the third region A3 is as follows: When viewed from the Z direction, during laser processing near 145° and 75° on line A, cracks extending from the modified region 12 are pulled in the direction of the nearest (111) planes K4 and K3, which tends to increase the meandering of the cut surface and worsen the processing quality. In contrast, when processing near 145° and 75°, by tilting the longitudinal direction NH of the focusing region C away from the (111) planes K4 and K3, the increase in the meandering of the cut surface is suppressed, and the deterioration of processing quality is suppressed. For this reason, during processing, the shape of the laser beam L's focusing region C is set to shape QA during processing of the second region A2 and the third region A3.

[0047] Thus, in the machining process, as shown in Figure 9, the focusing region C is defined as shape QB in the range of 0° to 55° of line A (first region A1), shape QA in the range of 55° to 90° of line A (third region A3), shape QB in the range of 90° to 125° of line A (fourth region A4), and shape QA in the range of 125° to 180° of line A (second region A2). In this example, the inclination angle of the longitudinal direction NH from the machining direction ND in shape QB, and the inclination angle of the longitudinal direction NH from the machining direction ND in shape QA, are both set to 10°.

[0048] As described above, a specific procedure for performing processing by changing the shape of the laser beam L focusing region C in each region of line A is as follows: In the processing process, while rotating stage 2 in a certain direction, the shape of the laser beam L focusing region C is set to shape QB, and the laser beam L is irradiated in the first region A1, the fourth region A4, the first region A5, and the fourth region A8, while the irradiation of the laser beam L is switched ON / OFF so that it is not irradiated in the other regions.

[0049] Next, during the processing, while rotating Stage 2 in a certain direction, the shape of the laser beam L focusing region C is set to shape QA, and the laser beam L is irradiated in the third region A3, the second region A2, the third region A7, and the second region A6, while the irradiation of the laser beam L is switched ON / OFF so that it is not irradiated in the other regions.

[0050] In these cases, the rotation direction of Stage 2, i.e., the machining direction ND, can be the same for all of them. That is, the control unit 6 can make the machining direction ND in the first region A1, A5 and the fourth region A4, A8 the same for the machining direction ND in the second region A2, A6 and the third region A3, A7 (however, they may be opposite for all of them). Also, in this example, the control unit 6 will irradiate the laser beam L in the first region A1, A5 and the fourth region A4, A8 with laser beam L, and then irradiate the laser beam L in the second region A2, A6 and the third region A3, A7 with laser beam L.

[0051] As a result of the above processing, a modified region 12 and cracks 13 extending from the modified region 12 are formed on the object 11 along the entire length of line A, as shown in Figures 10 and 11. Subsequently, in the processing, a laser beam L is irradiated along another line Ad that extends linearly from the outer edge of the object 11 to line A, thereby forming a modified region 12 and cracks along line Ad (radiation cutting). This makes it possible to divide the removal region E into multiple arc-shaped parts, facilitating the cutting out of the effective region R.

[0052] Furthermore, after the above processing, the object 11 can be ground from the first surface 11a side to remove the second portion 15B and a portion of the first portion 15A. The portion of the first portion 15A that is removed is the portion in which the modified regions 12a and 12b are formed. Therefore, the remaining portion of the first portion 15A does not include the modified regions 12a and 12b.

[0053] In this embodiment, by performing processing at multiple positions in the Z direction, modified regions 12 and cracks 13 are formed at multiple positions in the Z direction of the object 11. As described above, oblique cracks 13F are formed in the first part 15A of the object 11, and vertical cracks 13c and 13d are formed in the second part 15B of the object 11.

[0054] The formation of the oblique crack 13F in the first portion 15A can be carried out as follows, for example. Specifically, a modified region 12a is formed by positioning the focusing region C at a first position in the Z direction and irradiating it with laser light L, and a modified region 12b is formed by positioning the focusing region C at a second position closer to the incident surface (first surface 11a) than the first position in the Z direction and irradiating it with laser light L. At this time, the position in the Y direction of the focusing region C when forming the modified region 12b is shifted towards the center of the object 11 relative to the position in the Y direction of the focusing region C when forming the modified region 12a. The Y direction is the direction that intersects the Z direction and the X direction, which is the processing progress direction ND.

[0055] Furthermore, by modulating the laser light L using the spatial light modulator 7, the shape of the focusing region C in the XY plane is made to be a sloping shape that is inclined toward the negative Y direction (towards the center of the object 11) with respect to the Z direction, at least on the first surface 11a side (positive Z direction side) from the center Ca of the focusing region C. This connects the crack 13a extending from the modified region 12a and the crack 13b extending from the modified region 12b, and forms an oblique crack 13F that slopes toward the outside of the object 11 as it approaches the device layer 110 side of the object 11. In particular, here the tip of the oblique crack 13F on the second surface 11b side can reach the outer edge 110e of the junction region between the device layer 110 and the device layer 110R.

[0056] Here, as shown in Figure 8, the control unit 6 controls the rotation direction of the stage 2 to control the forward and reverse of the processing direction ND, thereby making the inclination direction NHa of the longitudinal direction NH of the laser beam L focusing region C with respect to the processing direction ND match the extension direction NT of the oblique crack 13F when viewed from the Z direction. In this case, the deterioration of processing quality can be further suppressed. However, it is not necessary to match the inclination direction NHa with the extension direction NT.

[0057] As described above, the object to be processed 11 of the laser processing apparatus 1 and laser processing method according to this embodiment has a first surface 11a as its main surface, which is the (110) surface that is the incident surface of the laser beam L. An annular line A is set so as to intersect the (110) surfaces K1, (100) surfaces K2, and (111) surfaces K3, K4 that intersect the first surface 11a when viewed from the Z direction intersecting the first surface 11a. Furthermore, when viewed from the Z direction, line A has intersections with (110) plane K1 at 0° and 180°, intersections with (100) plane K2 at 90°, a point of tangency with one (111) plane K3 at 55°, and a point of tangency with another (111) plane K4 intersecting one (111) plane K3 at 125°. This includes a first region A1 containing a point at 35° between 0° and 55°, and a second region A2 containing a point at 145° between 125° and 180°.

[0058] When the laser beam L is irradiated onto the first region A1 of line A, the longitudinal direction NH of the focusing region C of the laser beam L is tilted away from the (111) plane K3 with respect to the processing direction ND. Similarly, when the laser beam L is irradiated onto the second region A2 of line A, the longitudinal direction NH of the focusing region C of the laser beam L is tilted away from the (111) plane K4 with respect to the processing direction ND. In this way, the deterioration of processing quality is suppressed at 35° and 145°, where quality deterioration tends to be significant. Therefore, this laser processing apparatus 1 and laser processing method can suppress the deterioration of processing quality for objects having the above-described relationship between line A and crystal orientation.

[0059] Furthermore, in the laser processing apparatus 1 and laser processing method according to this embodiment, line A includes a third region A3 that includes 75° between 55° and 90°, and a fourth region A4 that includes 105° between 90° and 125°. When the control unit 6 irradiates the third region A3 of line A with laser light L during the processing, it controls the spatial light modulator 7 to shape the laser light L, thereby tilting the longitudinal direction NH away from the (111) plane K3 with respect to the processing direction ND. Also, when the control unit 6 irradiates the fourth region A4 of line A with laser light L, it controls the spatial light modulator 7 to shape the laser light L, thereby tilting the longitudinal direction NH away from the (111) plane K4 with respect to the processing direction ND. In this case, even in the 75° and 105° sections of line A, where quality deterioration tends to be somewhat more pronounced, the deterioration of processing quality is suppressed.

[0060] These effects will be explained in detail. Figure 13 is a photograph showing the cross-section of an object at various processing angles on the line. Each photograph in Figure 13 is a conventional processing example where control is not performed to tilt the longitudinal direction NH of the laser beam L focusing region C away from the (111) planes K3 and K4 with respect to the processing direction ND. As shown in Figures 13(a) and (d), when the processing angles are 15° and 85°, crack meandering in the cross-section is not significantly apparent, whereas as shown in Figures 13(b) and (c), when the processing angles are 35° and 75°, crack meandering in the cross-section is significantly apparent, and a decrease in processing quality is confirmed. In particular, when the processing angle is 35°, the amount of crack meandering is about 8 μm, and the greatest decrease in processing quality is confirmed, followed by when the processing angle is 75°, the amount of crack meandering is about 5 μm, and a decrease in processing quality is confirmed. The cracks used for evaluating the amount of meandering here are those that have reached the surface opposite to the incident surface of the laser beam L (for example, the second surface 11b).

[0061] Figure 14(a) shows the processing result when the processing angle is 35°, and the shape of the laser beam L focusing region C is QA instead of the expected shape QB, i.e., when the longitudinal direction NH is tilted so that it approaches the (111) surface K3 closest to the processing direction ND at a 35° angle (the tilt angle is 10°). In this case, the amount of crack meandering in the cut surface was about 8 μm, showing no improvement, and a significant decrease in processing quality was still observed.

[0062] Figures 14(b) and (c) show the processing results when the processing angle is 35° and the shape of the laser beam L focusing region C is set to shape QB, that is, when the longitudinal direction NH is tilted 35° away from the nearest (111) surface K3 with respect to the processing direction ND. (The tilt angles are 10° and 45°, respectively). In this case, the amount of crack meandering in the cut surface was improved to about 4 μm, and the suppression of the deterioration of processing quality was confirmed.

[0063] Figures 15(b) and (c) show the processing results when the processing angle is 75°, and the shape of the laser beam L focusing region C is QB instead of the expected shape QA, i.e., when the longitudinal direction NH is tilted so that it approaches the (111) surface K3 closest to the processing direction ND at 75° (the tilt angles are 10° and 45°). In this case, no improvement was observed in the amount of crack meandering in the cut surface, which was around 5 μm to 8 μm, and a significant decrease in processing quality was still confirmed.

[0064] Figure 15(a) shows the machining result when the machining angle is 75° and the shape of the laser beam focusing region C is defined as shape QA, that is, when the longitudinal direction NH is tilted 75° away from the nearest (111) surface K3 with respect to the machining direction ND (the tilt angle is 10°). In this case, the amount of crack meandering in the cut surface was improved to about 1 μm, and the suppression of the deterioration of machining quality was confirmed.

[0065] From the results above, it can be understood that the deterioration of processing quality can be suppressed by controlling the longitudinal direction NH of the focusing region C of the laser beam L to tilt away from the (111) planes K3 and K4 according to the processing angle with respect to the processing direction ND.

[0066] In the laser processing apparatus 1 and laser processing method according to this embodiment, the control unit 6 may set the processing direction ND in the first region A1 and the processing direction ND in the second region A2 to be the same during the processing. In this case, there is no need to change the processing direction ND between processing the first region A1 and processing the second region A2, and the processing time is shortened.

[0067] Furthermore, in the laser processing apparatus 1 and laser processing method according to this embodiment, the control unit 6 may, in the processing process, perform irradiation of the laser beam L in the second region A2 and the third region A3 after irradiating the first region A1 and the fourth region A4 with the laser beam L. In this case, by grouping together processing in each region of line A where the shape of the laser beam L focusing region C is common (i.e., processing where the inclination direction NHa with respect to the processing progress direction ND in the longitudinal direction NH is the same), the control of the spatial light modulator 7 becomes easier.

[0068] Furthermore, in the laser processing apparatus 1 and laser processing method according to this embodiment, the first region A1 is a region extending from 0° to 55°, the third region A3 is a region extending from 55° to 90° and has a boundary with the first region A1, the fourth region A4 is a region extending from 90° to 125° and has a boundary with the third region A3, and the second region A2 is a region extending from 125° to 180° and has a boundary with the fourth region A4. Therefore, the region of line A between 0° and 180° (and similarly the region between 180° and 360°) is composed of two types of regions (the first and third regions and the second and fourth regions) in which the shape of the laser beam L focusing region C is different from each other. Consequently, the number of times conditions are switched during processing in these regions (for example, twice) is reduced, making it possible to shorten the processing time.

[0069] The above embodiments describe one aspect of the present invention. Therefore, the present invention is not limited to the above embodiments, and the above embodiments can be modified as needed.

[0070] Next, we will explain some modifications. Figure 16 is a schematic diagram showing the processing steps related to the modifications. As shown in Figure 16, in the processing steps, the focusing region C may be shaped as QB in the range of 0° to 60° of line A, as shaped as QA in the range of 60° to 90° of line A, as shaped as QB in the range of 90° to 120° of line A, and as shaped as QA in the range of 120° to 180° of line A.

[0071] In this case, with respect to line A, the first region A1 is defined as the region including the point at 35° between 0° and 60°, the second region A2 is defined as the region including 145° between 120° and 180°, the third region A3 is defined as the region including 75° between 60° and 90°, and the fourth region A4 is defined as the region including 105° between 90° and 130°. In particular, in this example, the first region A1 is the region from 0° to 60°, the third region A3 is the region from 60° to 90° and has a boundary with the first region A1, the fourth region A4 is the region from 90° to 120° and has a boundary with the third region A3, and the second region A2 is the region from 120° to 180° and has a boundary with the fourth region A4.

[0072] In this way, it is possible to provide a certain margin (for example, about ±5°) at the boundaries of each region (the points where the shape of the focusing region C changes). In the example in Figure 16, the inclination angle of the longitudinal direction NH of the focusing region C in the first region A1 and the second region A2, which include 35° and 145° respectively, where the quality degradation is most pronounced (here, 20°), is made larger than the inclination angle of the longitudinal direction NH of the focusing region C in the other third region A3 and fourth region A4 (here, 10°). That is, the control unit 6 can make the inclination angle of the longitudinal direction NH with respect to the processing direction ND when irradiating the first region A1 and the second region A2 with laser light L, larger than the inclination angle of the longitudinal direction NH with respect to the processing direction ND when irradiating the third region A3 and the fourth region A4 with laser light L, by controlling the spatial light modulator 7 during the processing process. In this case, the deterioration of processing quality can be more effectively suppressed in each of the following areas: the first area A1 and the second area A2, and the third area A3 and the fourth area A4.

[0073] Figure 17 is a schematic diagram showing a processing procedure related to another modified example. As shown in Figure 17, in the processing procedure, the focusing region C may be shaped as QB in the range of 0° to 50° of line A, as shaped as QA in the range of 50° to 90° of line A, as shaped as QB in the range of 90° to 130° of line A, and as shaped as QA in the range of 130° to 180° of line A.

[0074] In this case, with respect to line A, the first region A1 is defined as the region including the point at 35° between 0° and 50°, the second region A2 is defined as the region including 145° between 130° and 180°, the third region A3 is defined as the region including 75° between 50° and 90°, and the fourth region A4 is defined as the region including 105° between 90° and 120°. In particular, in this example, the first region A1 is the region from 0° to 50°, the third region A3 is the region from 50° to 90° and has a boundary with the first region A1, the fourth region A4 is the region from 90° to 130° and has a boundary with the third region A3, and the second region A2 is the region from 130° to 180° and has a boundary with the fourth region A4.

[0075] Furthermore, in this example, the first region A1 includes a first portion A1a containing 35° and a first front portion A1b located 0° to the first portion A1a, and the second region A2 includes a second portion A2a containing 145° and a second rear portion A2b located 180° to the second portion A2a. The control unit 6 then controls the spatial light modulator 7 during the processing to make the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the first portion A1a and the second portion A2a greater than the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the first front portion A1b and the second rear portion A2b.

[0076] In this case, when processing at 35° and 145°, where the deterioration of processing quality in the first region A1 and second region A2 is particularly pronounced, the decline in processing quality can be reliably suppressed by relatively increasing the tilt angle of the longitudinal direction NH of the laser beam L focusing region C. Furthermore, when processing areas where the deterioration of processing quality is not particularly pronounced, such as the first front portion A1b, which is closer to 0° in the first region A1, and the second rear portion A2b, which is closer to 180° in the second region A2, the decline in processing quality due to the tilt of the longitudinal direction NH of the laser beam L focusing region C can be suppressed by relatively decreasing the tilt angle of the longitudinal direction NH of the laser beam L focusing region C.

[0077] Figure 18 is a schematic diagram showing the processing of yet another modified example. As shown in Figure 18, the first region A1 can be a portion of the region between 0° and 60° (here, the region from 20° to 45°), the third region A3 can be a portion of the region between 60° and 90° (here, the region from 65° to 80°), the fourth region A4 can be a portion of the region between 90° and 120° (here, the region from 100° to 115°), and the second region A2 can be a portion of the region between 120° and 180° (here, the region from 135° to 160°).

[0078] Then, during the processing, the control unit 6 controls the spatial light modulator 7 to prevent the longitudinal direction NH of the laser beam L from being tilted with respect to the processing direction ND when irradiating laser beam L to areas other than the first region A1, second region A2, third region A3, and fourth region A4 in the area between 0° and 180° of line A (similarly for 180° and 360°), by controlling the spatial light modulator 7 (the tilt angle is set to 0°).

[0079] In this case, by preventing the longitudinal direction NH of the laser beam L focusing region C from being tilted in areas other than those in line A where the deterioration of processing quality is particularly pronounced, it is possible to suppress the deterioration of processing quality due to the tilt of the longitudinal direction NH of the laser beam L focusing region C when processing in areas where the deterioration of processing quality is relatively not pronounced.

[0080] Figure 19 is a schematic diagram showing another modified processing method. As shown in Figure 19, in this example, with respect to line A, the first region A1 is the region including the point at 35° between 0° and 55°, the second region A2 is the region including 145° between 125° and 180°, the third region A3 is the region including 75° between 55° and 90°, and the fourth region A4 is the region including 105° between 90° and 125°. In particular, in this example, the first region A1 is the region from 0° to 55°, the third region A3 is the region from 55° to 90° and has a boundary with the first region A1, the fourth region A4 is the region from 90° to 125° and has a boundary with the third region A3, and the second region A2 is the region from 125° to 180° and has a boundary with the fourth region A4.

[0081] In this example, the first region A1 includes a first portion A1a containing 35°, a first front portion A1b located 0° to the first portion A1a, and a first rear portion A1c located 55° to the first portion A1a. The second region A2 includes a second portion A2a containing 145°, a second front portion A2d located 125° to the second portion A2a, and a second rear portion A2c located 180° to the second portion A2a.

[0082] In this example, the third region A3 includes a third portion A3a containing 75° and a third front portion A3b located 55° further to the third portion A3a. Furthermore, the fourth region A4 includes a fourth portion A4a containing 145° and a fourth rear portion A4b located 125° further to the fourth portion A4a.

[0083] Then, during the processing, the control unit 6 controls the spatial light modulator 7 so that the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the first front portion A1b, the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the first portion A1a, and the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the first rear portion A1c increase in this order.

[0084] Furthermore, during the processing, the control unit 6 controls the spatial light modulator 7 so that the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the second rear portion A2c, the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the second portion A2a, and the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the second front portion A2d increase in this order.

[0085] Furthermore, during the processing, the control unit 6 controls the spatial light modulator 7 to make the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the third front portion A3b greater than the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the third portion A3a, and also makes the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the fourth rear portion A4b greater than the inclination angle of the longitudinal direction NH with respect to the processing direction ND when the laser beam L is irradiated onto the fourth portion A4a.

[0086] In this case, by further subdividing each region of line A and adjusting the tilt angle of the longitudinal direction NH of the laser beam focusing region C, it becomes possible to improve quality by searching for the optimal conditions in each part.

[0087] In the above embodiment, the case of trimming an object 11 which is a bonded wafer has been described, but the laser processing apparatus 1 and laser processing method according to this disclosure may be applied to other processing. Examples of other processing include inch-down processing, which cuts a smaller object from a single circular plate-shaped object, and it may also be applied to any other processing. [Explanation of Symbols]

[0088] 1...Laser processing device, 2...Stage (support unit), 4,5...Moving unit, 6...Control unit, 7...Spatial light modulator (forming unit), 11...Object.

Claims

1. A support part for supporting the object, An irradiation unit for irradiating the object supported by the support unit with laser light, A moving unit for moving the laser beam focusing region relative to the object, A control unit for controlling the moving unit and the irradiation unit, Equipped with, The object includes a main surface which is a (110) surface, a (100) surface, and a (111) surface, and is supported by the support portion such that the (110) surface becomes the incident surface of the laser light. The object has an annular line set to intersect with the (110) surface, the (100) surface, and the (111) surface, when viewed from the Z direction intersecting the incident surface, The line, viewed from the Z direction, has intersections with the other (110) plane at 0° and 180°, an intersection with the (100) plane at 90°, a point of contact with one of the (111) planes at 55°, and a point of contact with another (111) plane intersecting the first (111) plane at 125°, and includes a first region containing a point at 35° between 0° and 60°, and a second region containing a point at 145° between 120° and 180°. The irradiation unit has a forming unit that shapes the laser light such that the focusing region has a longitudinal direction when viewed from the Z direction. The control unit controls the irradiation unit and the moving unit to move the focusing area relative to the line, thereby performing a processing operation to irradiate the object along the line with the laser light and form a modified area. When the control unit irradiates the first region of the line with the laser light during the processing, it controls the molding unit to shape the laser light so that the longitudinal direction is tilted away from the first (111) plane with respect to the processing progress direction, which is the relative movement direction of the focusing region. The control unit, in the processing operation, when irradiating the second region of the line with the laser light, controls the molding unit to shape the laser light, thereby tilting the longitudinal direction away from the other (111) surface with respect to the processing direction. Laser processing equipment.

2. The control unit makes the machining direction in the first region and the machining direction in the second region the same during the machining process. The laser processing apparatus according to claim 1.

3. The line includes a third region including 75° between 50° and 90°, and a fourth region including 105° between 90° and 130°. When the control unit irradiates the third region of the line with the laser light during the processing, it controls the molding unit to shape the laser light, thereby tilting the longitudinal direction away from the first (111) plane with respect to the processing direction. The control unit, in the processing operation, when irradiating the fourth region of the line with the laser light, controls the molding unit to shape the laser light so that the longitudinal direction is tilted away from the other (111) surface with respect to the processing direction. The laser processing apparatus according to claim 1.

4. The control unit, in the processing process, controls the molding unit to make the inclination angle of the longitudinal direction with respect to the processing direction greater than the inclination angle of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first and second regions. The laser processing apparatus according to claim 3.

5. The control unit, in the processing operation, performs irradiation of the laser beam in the first region and the laser beam in the fourth region, and then performs irradiation of the laser beam in the second region and the laser beam in the third region. The laser processing apparatus according to claim 3 or 4.

6. The first region is the region extending from 0° to 55°, The third region is the region extending from 55° to 90° and has a boundary with the first region. The fourth region is the region extending from 90° to 125°, and has a boundary with the third region. The second region is the region extending from 125° to 180° and having a boundary with the fourth region. The laser processing apparatus according to claim 3 or 4.

7. The first region is the region extending from 0° to 60°, The third region is the region extending from 60° to 90° and has a boundary with the first region. The fourth region is the region extending from 90° to 120°, and has a boundary with the third region. The second region is the region extending from 120° to 180° and having a boundary with the fourth region. The laser processing apparatus according to claim 3 or 4.

8. The first region includes a first portion including the 35° and a first front portion on the 0° side of the first portion. The second region includes a second portion including the 145° and a second rear portion that is 180° further than the second portion. The control unit, in the processing process, controls the molding unit to make the inclination angle of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first portion and the second portion greater than the inclination angle of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first front portion and the second rear portion. The laser processing apparatus according to claim 1.

9. The first region is a part of the region between 0° and 60°, The third region is a part of the region between 60° and 90°, The fourth region is a part of the region between 90° and 120°, The second region is a part of the region between 120° and 180°, The control unit controls the molding section in the processing process so that when the laser beam is irradiated onto areas other than the first, second, third, and fourth areas between 0° and 180° of the line, the longitudinal direction is not tilted with respect to the processing direction. The laser processing apparatus according to claim 3.

10. The first region includes a first portion including the 35°, a first front portion on the 0° side of the first portion, and a first rear portion on the 60° side of the first portion. The second region includes a second portion including the 145°, a second front portion 120° further than the second portion, and a second rear portion 180° further than the second portion. The control unit controls the molding unit in the processing process so that the inclination angle of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first front portion, the inclination angle of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first portion, and the inclination angle of the longitudinal direction with respect to the processing direction when the laser light is irradiated onto the first rear portion increase in this order. The control unit controls the molding unit during the processing process so that the inclination angle of the longitudinal direction with respect to the processing direction when the laser beam is irradiated onto the second rear portion, the inclination angle of the longitudinal direction with respect to the processing direction when the laser beam is irradiated onto the second portion, and the inclination angle of the longitudinal direction with respect to the processing direction when the laser beam is irradiated onto the second front portion increase in this order. The laser processing apparatus according to claim 1.

11. A laser processing method comprising irradiating an object with laser light while moving the focusing region of the laser light relative to the object, The process includes a step of irradiating the object with laser light along the line, thereby forming a modified region, by moving the focusing area relative to the object along the line set on the object. The object includes a main surface which is a (110) surface, a (100) surface, and a (111) surface, and is supported such that the (110) surface becomes the incident surface of the laser light. The line is set in a ring shape so as to intersect with another (110) plane, the (100) plane, and the (111) plane, when viewed from the Z direction intersecting the incident plane, the main plane (110) plane. The line, viewed from the Z direction, has intersections with the other (110) plane at 0° and 180°, an intersection with the (100) plane at 90°, a point of contact with one of the (111) planes at 55°, and a point of contact with another (111) plane intersecting the first (111) plane at 125°, and includes a first region containing a point at 35° between 0° and 60°, and a second region containing a point at 145° between 120° and 180°. In the processing step, when the laser light is irradiated onto the first region of the line, the laser light is shaped such that the focusing region has a longitudinal direction, and the longitudinal direction is tilted away from the first (111) plane with respect to the processing progress direction, which is the relative movement direction of the focusing region. In the processing step, when the laser beam is irradiated onto the second region of the line, the laser beam is shaped such that the focusing region has a longitudinal direction, and the longitudinal direction is tilted away from the other (111) surface with respect to the processing direction. Laser processing method.

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