Laser processing device, and laser processing method

Abstract

A laser processing device for forming a modified region along a virtual surface inside an object along the incident surface of the laser light of the object by irradiating the object with laser light, comprising: a support member for supporting the object; an irradiation member for irradiating the laser light onto the object supported by the support member; a moving member for moving at least one of the support member and the irradiation member so that a focused spot of the laser light moves along the virtual surface; and a control member for controlling the support member, the irradiation member, and the moving member. The irradiation member comprises a spatial light modulator for modulating the laser light and a focusing member for focusing the laser light that has passed through the spatial light modulator toward the object.

Description

Technology Field

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

[0002] Patent Document 1 describes a substrate processing system. In this substrate processing system, a modified layer is first formed in a ring shape by irradiating a laser light along the boundary between the peripheral edge portion and the central portion of the wafer to be removed. Subsequently, a modified surface is formed by irradiating a laser light along the unprocessed surface of the wafer to be processed, which is the surface bonded to the support wafer, and where the device layer is formed. Subsequently, the peripheral edge portion of the wafer to be processed is peeled off and removed starting from the modified layer and a crack extending from the modified layer in the plate thickness direction. At this time, since the modified surface is formed at the interface between the wafer to be processed and the support wafer, the bonding force between the wafer to be processed and the support wafer is reduced, and the peripheral edge portion can be properly removed. After that, finishing grinding is performed on the processed surface of the wafer to be processed. Prior art literature

[0003] Japanese Patent Publication No. 2022-002312 The problem to be solved

[0004] In the substrate processing system described in the above patent document 1, a modified surface is formed by rotating a chuck on which a wafer to be processed is placed, moving a laser head outward in the radial direction, and irradiating a laser beam into the interior of the wafer to be processed. In this case, a plurality of modified regions arranged in the Y direction are formed within a YZ plane that includes a Z direction intersecting the incident plane of the laser beam in the object to be processed, such as the wafer to be processed, and a Y direction which is the radial direction. In particular, in this case, a plurality of modified regions are formed sequentially within the YZ plane from one side in the Y direction toward the other (from the inner side in the radial direction toward the outer side).

[0005] When multiple modified regions arranged in the Y direction are formed sequentially in a first Y direction extending from one side of the Y direction to the other, there is a risk that cracks extending from the modified region toward the first Y direction may propagate at an angle with respect to the first Y direction. In particular, among the multiple modified regions, cracks extending toward the first Y direction from the last modified region formed may propagate further, for example, due to the crystal structure of the object. If such cracks propagate and reach the bottom surface opposite to the incident surface of the object, there is a risk of damage to structures such as the device layer formed on the bottom surface or other wafers bonded to the bottom surface. Therefore, there is a need to suppress the propagation of cracks so that cracks extending from the modified region do not reach the bottom surface.

[0006] Therefore, the present disclosure aims to provide a laser processing apparatus and a laser processing method capable of suppressing the progression of cracks extending from a modified region. means of solving the problem

[0007] A laser processing device according to the present disclosure [1] is a laser processing device for forming a modified region along a virtual plane inside an object along the incident plane of the laser light of the object by irradiating the object with a laser light, comprising a support member for supporting the object, an irradiation member for irradiating the laser light to the object supported by the support member, a moving member for moving at least one of the support member and the irradiation member so that the laser light collecting spot moves along the virtual plane, and a control member for controlling the support member, the irradiation member, and the moving member, wherein the irradiation member comprises a spatial light modulator for modulating the laser light and a collecting member for collecting the laser light that has passed through the spatial light modulator toward the object, and the control member performs X-direction processing to form a first modified region as the modified region by irradiating the laser light to the object while moving the collecting spot in the X direction along the virtual plane, wherein the collecting spot in the Y direction that follows the virtual plane and intersects the X direction A laser processing device that performs a first processing process to form a plurality of first modified regions arranged along the Y direction within a YZ plane including a Z direction intersecting the X direction and the Y direction and the Y direction by changing the position of the spot from one side of the Y direction to the other, and in the first processing process, the control unit modulates the laser light by the spatial light modulator such that the beam shape at the focusing spot of the laser light within the YZ plane is inclined toward the first Y direction with respect to the Z direction at least on the incident plane side relative to the center of the focusing spot.

[0008] A laser processing method according to the present disclosure

[10] is a laser processing method for forming a modified region along a virtual plane inside the object along the incident plane of the laser light of the object by irradiating the object with a laser light, and comprises a processing process for forming the modified region by irradiating the laser light of the object while moving the laser light spot of the laser light along the virtual plane, and in the processing process, a first processing is performed to form a plurality of the first modified regions arranged along the Y-direction within the YZ plane including the X-direction and the Y-direction, by irradiating the laser light of the object while moving the laser light spot along the X-direction within the virtual plane, thereby forming a first modified region as the modified region along the X-direction, and by changing the position of the laser light spot in the Y-direction that intersects the X-direction along the virtual plane and the X-direction to a first Y-direction that intersects the X-direction and the Y-direction, and by changing the position of the laser light spot in the Y-direction that intersects the X-direction and the X-direction to a first Y-direction that intersects the X-direction and the Y-direction. In the first processing, the A laser processing method in which the beam shape of the laser light at the concentration spot within the YZ plane is inclined toward the first Y direction at least on the side of the incident plane than the center of the concentration spot.

[0009] In this apparatus and method, within a virtual plane along the incident plane of the laser light of the object, a laser light is irradiated while moving a focusing spot along the X direction along the virtual plane to form a first modification region along the X direction. By performing X-direction processing that forms a first modification region along the X direction while changing the position of the focusing spot in the Y direction intersecting the X direction along the virtual plane to a first Y direction extending from one side of the Y direction to the other, a plurality of first modification regions arranged along the Y-direction within the YZ plane are formed. In this case, as described above, there is a risk that cracks extending from the plurality of first modification regions toward the first Y direction may advance at an angle with respect to the first Y direction. In particular, among the plurality of first modification regions, cracks extending from the last formed first modification region toward the first Y direction may advance further, for example, due to the crystal structure of the object.

[0010] In this regard, in the apparatus and method, when forming the first modification region, the beam shape of the laser light concentration spot in the YZ plane is inclined toward the first Y direction at least toward the incident plane side from the center of the concentration spot. By using a concentration spot having such a beam shape when forming the first modification region, the crack extending from the first modification region toward the first Y direction is suppressed from advancing obliquely toward the side opposite to the incident plane of the object (i.e., the bottom side). That is, according to the apparatus and method, it is possible to suppress the advancement of the crack extending from the modification region.

[0011] The laser processing device according to the present disclosure may be [2] a laser processing device described in [1], wherein “a plurality of lines arranged in a concentric shape when viewed from the Z direction are set on the object, and the control unit irradiates the object with the laser light while moving the light-gathering spot along one of the lines to form the first modification area along the X direction as the circumferential direction of the one line, and performs the X-direction processing across the plurality of lines while changing the one line to the first Y direction to form the plurality of first modification areas arranged in the YZ plane along the Y direction as the diameter direction of the line.” In this way, when processing (concentric processing) is performed along a plurality of lines arranged in a concentric shape, unlike when processing (spiral processing) is performed along a spiral-shaped line, for example, the spacing of the modification areas in the Y direction within the YZ plane can be kept constant, thereby enabling stable processing.

[0012] The laser processing device according to the present disclosure [3] may be the laser processing device described in [1], wherein “a spiral-shaped line is set on the object when viewed from the Z direction, and the control unit irradiates the object with the laser light while moving the light-gathering spot along the line, thereby forming the first modification area along the X direction as the tangential direction of the line, and by performing the X-direction processing from the beginning to the end of the line, thereby forming a plurality of the first modification areas arranged along the Y-direction as the direction intersecting the tangential direction of the line within the YZ plane.” In this way, when performing spiral processing, it is possible to perform processing continuously along a single line. Because of this, the tact can be improved, and stable processing is possible because the effect of the rise when the laser is turned on is limited to only one point at the processing start point.

[0013] A laser processing device according to the present disclosure may be [4] a laser processing device described in any of [1] to [3], wherein the object has a first region including the center of the object when viewed from the Z direction, and a second region including the periphery edge of the object as a region outside the first region, and the control unit performs the first processing treatment on the first region. In this case, it is possible to perform a peeling process using a first modified region formed along a virtual plane while suppressing the propagation of cracks in the first region including the center of the object. Here, when peeling of the object is performed using a modified region formed along a virtual plane and a crack extending from the modified region, the longer the crack extending from the modified region toward the part remaining after peeling, the rougher the peeled surface becomes. In contrast to this, here, since the propagation of cracks extending from the first modified region formed along the virtual plane is suppressed, the roughness of the peeled surface is suppressed and the quality of the peeled surface is improved.

[0014] A laser processing device according to the present disclosure may be [5] a laser processing device described in any of [1] to [3], wherein the object has a first region including the center of the object when viewed from the Z direction, and a second region including the periphery edge of the object as a region outside the first region, and the control unit performs the first processing treatment on the second region. In this case, it is possible to perform a peeling process using a first modified region formed along a virtual plane in the second region including the periphery edge of the object while suppressing the propagation of cracks. In this case, for the same reason as in [4], when peeling of the object is performed using the first modified region formed along the virtual plane and the crack extending from the first modified region, roughening of the peeled surface is suppressed and the quality of the peeled surface is improved.

[0015] A laser processing device according to the present disclosure [6] “The second region has a boundary with the first region, and the control unit performs a second processing process after the first processing process, wherein a plurality of second modification regions are positionally intersecting with a plurality of first modification regions arranged along the Y direction at the boundary, and in the second processing process, the control unit modulates the laser light by controlling the spatial light modulator so that a third modification region, which is the second modification region closest to the first modification region among the plurality of second modification regions, becomes elongated in the Z direction, thereby imparting a first aberration to the laser light, and the third modification region is the second modification region furthest from the incident plane among the plurality of second modification regions, and the first aberration is the aberration that occurs in the direction of the optical axis of the laser light at the focusing position due to the focusing of the laser light by the focusing unit, and the focusing of the laser light to which the reference aberration is imparted The laser processing device described in [5] may be a device for forming a concentrated spot in the shape of a long rod in the Z direction rather than a spot.

[0016] The elongated third modified region formed in this manner has the property that cracks extending from the third modified region are difficult to propagate in the Z-direction (i.e., the cracks become short). Because of this, since it is difficult for cracks to extend from the third modified region, the propagation of cracks from the third modified region to the bottom surface of the object (the surface opposite to the incident surface) is suppressed.

[0017] Meanwhile, cracks extending from multiple first modified regions arranged in the Y direction may further advance by connecting with cracks extending from other modified regions if another modified region is formed close to the first modified region. In this regard, the second modified region closest to the first modified region serves as a third modified region where cracks are difficult to extend. In such a case, the phenomenon of cracks extending from the first modified region further advancing due to the formation of the third modified region is unlikely to occur. In other words, the advancement of cracks from the first modified region to the bottom surface of the object is suppressed. As described above, in this case, it is possible to reliably suppress the advancement of cracks extending from the modified region.

[0018] A laser processing device according to the present disclosure may be [7] a laser processing device described in [6], wherein the boundary comprises an inclined portion that is inclined with respect to the Z direction within a YZ plane including the Z direction and the Y direction, and the control unit modulates the laser light by controlling the spatial light modulator so that when forming the modification area in the inclined portion, the beam shape of the laser light at the focusing spot within the YZ plane is inclined in the direction of the inclined portion at least on the incident plane side rather than at the center of the focusing spot. In this case, it is possible to form a crack that extends obliquely with respect to the Z direction from the modification area along the inclined boundary. By doing so, it is possible to reduce the impact on structures on the bottom side, such as a device layer or another wafer, compared to the case where the crack extending from the modification area advances along the Z direction and reaches the bottom surface.

[0019] The laser processing device according to the present disclosure may be [8] a laser processing device described in any of [1] to [7], wherein, in the first processing process, the control unit branches the laser light so that at least a plurality of the concentrated spots with different positions in the Y direction are formed within the virtual plane. In this way, by forming a plurality of concentrated spots with different positions in the Y direction through the branching of the laser light, cracks extending from each of the first modified regions formed corresponding to the plurality of concentrated spots are easily connected to each other within the XY plane. As a result, the oblique progression of cracks extending from the first modified region toward the bottom side is suppressed.

[0020] The laser processing device according to the present disclosure may be [9] the laser processing device described in [8], wherein, in the first processing process, the control unit branches the laser light to form a plurality of the concentrating spots in the X direction that are additionally different in the virtual plane. In this case, cracks extending from each of the first modified regions formed corresponding to the plurality of concentrating spots become more easily connected to each other in the XY plane. As a result, the oblique progression of cracks extending from the first modified region toward the bottom side is more reliably suppressed. Effects of the invention

[0021] According to the present disclosure, a laser processing apparatus and a laser processing method capable of suppressing the progression of cracks extending from a modified region can be provided. Brief explanation of the drawing

[0022] FIG. 1 is a schematic diagram showing the configuration of a laser processing device according to one embodiment. Figure 2 is a schematic diagram showing the configuration of the investigation unit illustrated in Figure 1. FIG. 3 is a drawing showing an object to be laser processed according to a first embodiment. FIG. 4 is a drawing for explaining a laser processing method according to a first embodiment. FIG. 4 (a) is a schematic side view showing the formation of a modified region, and FIG. 4 (b) is a schematic side view showing the state in which the modified region is formed. FIG. 5 is a drawing for explaining a laser processing method according to a first embodiment. FIG. 5 (a) is a plan view, and FIG. 5 (b) is a schematic side view. FIG. 6 is a drawing for explaining a laser processing method according to a first embodiment. FIG. 6 (a) is a schematic side view showing a state in which a laser light is irradiated, and FIG. 6 (b) and (c) are a schematic plan view and a side view, respectively, showing a state in which a modified region is formed. FIG. 7 is a drawing showing an example of an object shown in FIG. 5 and FIG. 6. FIG. 7 (a) is a perspective view with a portion cut out, and FIG. 7 (b) is a schematic cross-sectional view. FIG. 8 is a cross-sectional view showing an example of a modified area and crack formation for the object shown in FIG. 7. FIG. 8 (a) and (b) are schematic cross-sectional views showing the progression of a crack. FIG. 9 is a diagram illustrating the relationship between the first Y direction, which is the direction of movement of the light-concentrating spot in the YZ plane, and the progression of the crack. FIG. 9 (a) is a schematic side view showing the movement of the light-concentrating spot, and FIG. 9 (b) is a schematic cross-sectional view showing the extension of the crack from the modified region within the YZ plane. FIG. 10 is a diagram illustrating the relationship between the first Y direction, which is the direction of movement of the light-concentrating spot in the YZ plane, and the progression of the crack. FIG. 10 (a) is a schematic side view showing the movement of the light-concentrating spot, and FIG. 10 (b) is a schematic cross-sectional view showing the extension of the crack from the modified region within the YZ plane. FIG. 11 is a diagram illustrating the relationship between the beam shape at the light-concentrating spot and the direction of crack propagation. FIG. 11 (a) is a diagram showing the beam shape at the light-concentrating spot, and FIG. 11 (b) is a cross-sectional photograph showing a modified area and a crack extending from the modified area. FIG. 12 is a diagram showing the relationship between each beam shape and the processing result when the first Y direction (ND) is the Y-plus direction. FIG. 13 is a diagram showing an example of a beam shape in a concentrating spot. FIG. 13 (a) shows a beam shape in the YZ plane, and FIG. 13 (b) shows a beam shape (intensity distribution) in each cross section (i.e., XY plane) of F1 to F7 in FIG. 13 (a). FIG. 14 is a drawing for explaining the post-process of a laser processing method according to a first embodiment. FIG. 14 (a) and (b) are schematic side views. FIG. 15 is a drawing for explaining a laser processing method according to a second embodiment. FIG. 15 (a) is a plan view, and FIG. 15 (b) is a schematic side view. FIG. 16 is a drawing for explaining a laser processing method according to a second embodiment. FIG. 16 (a) is a schematic cross-sectional view showing a state in which a light-gathering spot is positioned on a virtual plane, and FIG. 16 (b) is a schematic cross-sectional view showing a state in which a modified region is formed on a virtual plane. FIG. 17 is a drawing for explaining a laser processing method according to a second embodiment. Specifically, it is a schematic cross-sectional view showing a state in which a plurality of modified regions are formed along a virtual plane. FIG. 18 is a drawing for explaining a laser processing method according to a second embodiment. FIG. 18 (a) is a plan view, and FIG. 18 (b) is a schematic side view. FIG. 19 is a drawing for explaining a laser processing method according to a second embodiment. FIG. 19 (a) is a schematic cross-sectional view showing a state in which a focused spot is positioned at a boundary. FIG. 19 (b) is a schematic cross-sectional view showing a state in which a modified region is formed at a boundary. Figure 20 is a diagram illustrating the aberrations occurring at the focusing position of the laser light. FIG. 21 is a diagram showing the intensity and focusing spot of laser light when multiple aberrations are applied based on a reference aberration. FIG. 22 is a drawing for explaining a laser processing method according to a second embodiment. FIG. 22 (a) is a schematic cross-sectional view showing a state in which a focused spot is positioned at a boundary. FIG. 22 (b) is a schematic cross-sectional view showing a state in which a plurality of modified regions are formed arranged in the Z direction at the boundary. FIG. 23 is a drawing for explaining a laser processing method according to a modified example. Specifically, FIG. 23 (a) and (b) are schematic cross-sectional views showing the boundary between the effective area and the removal area in the object. FIG. 24 is a drawing for explaining a laser processing method according to a modified example. Specifically, FIG. 24 (a) and (b) are schematic cross-sectional views showing a modified region and a state in which a crack extending obliquely from the modified region is formed. FIG. 25 is a schematic cross-sectional (XY plane) view illustrating a laser processing method according to another modified example. FIG. 25 (a) is a schematic cross-sectional view showing a state in which a focused spot is formed. FIG. 25 (b) and (c) are schematic cross-sectional views showing a state in which a modified region is formed. FIG. 26 is a schematic cross-sectional (XY plane) view illustrating a laser processing method according to another modified example. FIG. 26 (a) is a schematic cross-sectional view showing a state in which a focused spot is formed. FIG. 26 (b) and (c) are schematic cross-sectional views showing a state in which a modified region is formed. FIG. 27 is a schematic cross-sectional (XY plane) view illustrating a laser processing method according to another modified example. FIG. 27 (a) is a schematic cross-sectional view showing a state in which a focused spot is formed. FIG. 27 (b) is a schematic cross-sectional view showing a state in which a modified region is formed. Specific details for implementing the invention

[0023] Hereinafter, an embodiment will be described with reference to the drawings. In addition, in each drawing, the same or equivalent parts are denoted by the same reference numerals, and redundant descriptions may be omitted. Also, each drawing may show an orthogonal coordinate system defined by the X-axis, Y-axis, and Z-axis.

[0024] FIG. 1 is a schematic diagram showing the configuration of a laser processing device according to one embodiment. As shown in FIG. 1, the laser processing device (1) is equipped with a stage (support part) (2), an irradiation part (3), a moving part (4, 5), and a control part (processing control part) (6). The laser processing device (1) is a device for forming a modified area (12) on an object (11) by irradiating a laser light (L) onto an object (11).

[0025] The stage (2) supports the object (11) by, for example, holding a film attached to the object (11). The stage (2) can rotate with an axis parallel to the Z direction as the axis of rotation. The stage (2) may be movable along the X direction and the Y direction, respectively. Additionally, the X direction and the Y direction are a first horizontal direction and a second horizontal direction that intersect (orthogonally) each other, and the Z direction is a vertical direction.

[0026] The irradiation unit (3) is intended to irradiate a laser beam (L) onto an object (11) supported on the stage (2). The irradiation unit (3) concentrates a laser beam (L) that is permeable to the object (11) and irradiates it onto the object (11). When the laser beam (L) is concentrated inside the object (11) supported on the stage (2), the laser beam (L) is particularly absorbed in a portion corresponding to the concentration spot (C) of the laser beam (L) (e.g., the center (Ca) shown in FIG. 18), and a modified region (12) is formed inside the object (11). Additionally, the concentration spot (C) is a region within a predetermined range from the center (Ca), which is the position where the beam intensity of the laser beam (L) is highest or the center of the beam intensity.

[0027] The modified region (12) is a region in which the density, refractive index, mechanical strength, and other physical properties differ from those of the surrounding non-modified region. Examples of the modified region (12) include a melting region, a crack region, an dielectric breakdown region, and a refractive index change region. The modified region (12) may be formed such that cracks extend from the modified region (12) toward the incident side of the laser light (L) and the opposite side. Such modified region (12) and cracks are used, for example, for cutting an object (11).

[0028] For example, by moving the stage (2) along the X direction, the focusing spot (C) is moved relative to the object (11) along the X direction, and a plurality of modification spots (12s) are formed to be arranged in a row along the X direction. One modification spot (12s) is formed by irradiation with a single pulse of laser light (L). A row of modification areas (12) is a collection of a plurality of modification spots (12s) arranged in a row. Adjacent modification spots (12s) may be connected to each other or separated from each other depending on the relative movement speed of the focusing spot (C) relative to the object (11) and the repetition frequency of the laser light (L).

[0029] The moving unit (4) includes a first moving unit (41) that moves the stage (2) in one direction within a plane intersecting (orthogonal) the Z direction, and a second moving unit (42) that moves the stage (2) in another direction within a plane intersecting (orthogonal) the Z direction. As an 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. Additionally, the moving unit (4) rotates the stage (2) using an axis parallel to the Z direction as the axis of rotation. The moving unit (5) supports the irradiation unit (3). The moving unit (5) moves the irradiation unit (3) along the X direction, the Y direction, and the Z direction. When the stage (2) and / or the irradiation unit (3) are moved while the laser light (L) is in a state where the light-gathering spot (C) is formed, the light-gathering spot (C) is moved relative to the object (11). That is, the moving part (4, 5) moves at least one of the stage (2) and the irradiation part (3) in order to move the focusing spot (C) of the laser light (L) relative to the object (11).

[0030] The control unit (6) controls the operation of the stage (2), the investigation unit (3), and the movement unit (4, 5). The control unit (6) has a processing unit, a memory unit, and an input receiving unit (not shown). The processing unit is configured as a computer device including a processor, memory, storage, and communication device. In the processing unit, the processor executes software (program) read into memory, etc., and controls the reading and writing of data in memory and storage, as well as communication by the communication device. The memory unit is, for example, a hard disk, and stores various data. The input receiving unit is an interface unit that displays various information and receives input of various information from the user. The input receiving unit is configured as a GUI (Graphical User Interface).

[0031] FIG. 2 is a schematic diagram showing the configuration of the irradiation unit illustrated in FIG. 1. FIG. 2 shows a hypothetical line (A) indicating the planned laser processing. As shown in FIG. 2, the irradiation unit (3) has a light source (31), a spatial light modulator (7), and a focusing lens (focusing unit) (33). The light source (31) outputs laser light (L) by, for example, a pulse oscillation method. Additionally, the irradiation unit (3) may be configured to introduce laser light (L) from outside the irradiation unit (3) without having a light source (31). 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) output from the spatial light modulator (7) (i.e., laser light that has passed through the spatial light modulator (7)) that has been modulated by the spatial light modulator (7) toward the target object (11).

[0032] 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 intended to modulate the laser light (L). In the spatial light modulator (7), when the modulation pattern is displayed, the laser light (L) is incident from the outside, reflected, and emitted outward, and the laser light (L) is modulated according to the displayed modulation pattern. In this way, according to the spatial light modulator (7), by appropriately setting the displayed modulation pattern, it is possible to modulate the laser light (L) (for example, modulation of the intensity, amplitude, phase, polarization, etc. of the laser light (L)).

[0033] As described above, laser light (L) output from the light source (31) passes through the spatial light modulator (7) and is incident on the focusing lens (33), and is focused within the object (11) by the focusing lens (33), thereby forming a modified area (12) and a crack extending from the modified area (12) in the object (11) at the focused spot (C). Additionally, by the control unit (6) controlling the moving unit (4, 5), the focused spot (C) is moved relative to the object (11), thereby forming a modified area (12) and a crack along the direction of movement of the focused spot (C).

[0034] [First Embodiment]

[0035] FIG. 3 is a drawing showing an object for laser processing according to a first embodiment. FIG. 3(a) is a top view, and FIG. 3(b) is a side view. As shown in FIG. 3, the object (11) is, for example, a silicon wafer. The object (11) includes a first surface (11a) and a second surface (11b) opposite to the first surface (11a). A device layer including a plurality of functional elements is formed on the second surface (11b) of the object (11). The object (11) is supported on the stage (2) such that the first surface (11a) faces the irradiation unit (3) side (i.e., the second surface (11b) faces the stage (2) side).

[0036] The object (11) includes an effective region (first region) (R) and a removal region (second region) (E). The effective region (R) is a portion corresponding to the semiconductor device to be acquired. Here, the effective region (R) is a disc-shaped portion including the center of the object (11) when viewed from the Z direction, which is the thickness direction of the object (11). The removal region (E) is a region located outside the effective region (R) in the object (11). In this embodiment, the removal region (E) is an outer edge portion other than the effective region (R) in the object (11). Here, the removal region (E) is a round ring-shaped portion surrounding the effective region (R). The removal region (E) includes the perimeter edge portion (outer edge bevel portion) of the object (11) when viewed from the Z direction.

[0037] In the object (11), a virtual surface (M1) is set as a surface scheduled for peeling. The virtual surface (M1) is a surface scheduled for the formation of a modified area (12). The virtual surface (M1) is a surface that follows the first surface (11a), which is the laser light incident surface of the object (100). The virtual surface (M1) is a surface parallel to the first surface (11a) and, for example, represents a circular shape. The virtual surface (M1) is a virtual area and is not limited to a flat plane, but may be a curved surface or a three-dimensional surface. The setting of the effective area (R), the removal area (E), and the virtual surface (M1) can be performed by the control unit (6). The effective area (R), the removal area (E), and the virtual surface (M1) may be coordinate-specified.

[0038] A line (M3) is set on the object (11) as a trimming line. The line (M3) is a line that is intended to form a modified area. The line (M3) extends in a ring shape on the inner side of the outer edge of the object (11). Here, the line (M3) extends in a round ring shape. The line (M3) is set at the boundary between the effective area (R) and the removal area (E) in a part opposite to the laser light incident surface from the virtual surface (M1) inside the object (11) (i.e., the line (M3) is also part of the boundary between the effective area (R) and the removal area (E)). The setting of the line (M3) can be performed by the control unit (6). The line (M3) is a virtual line, but it may be an actual line. The line (M3) may be a coordinate-specified line.

[0039] Next, a laser processing method for processing the above-described object (11) will be described. The laser processing method according to this embodiment is carried out by the laser processing device (1) described above. Accordingly, the laser processing method described below is also an example of processing performed by the laser processing device (1). That is, here, the control unit (6) controls the moving unit (4, 5) to move at least one of the stage (2) and the irradiation unit (3), thereby moving the focusing spot (C) of the laser light (L) relative to the object (11) and irradiating the laser light (L) onto the object (11), thereby performing laser processing to form a modified area (12) on the object (11).

[0040] In the laser processing method according to the present embodiment, first, trimming processing is performed. That is, as shown in FIG. 4, a laser light (L) is irradiated along the line (M3) to form a modified region (12) on a part opposite to the laser light incident surface (first surface (11a)) than the virtual surface (M1) inside the object (11) (process S101).

[0041] More specifically, in process S101, the irradiation unit (3) and / or stage (2) are moved so that the irradiation spot (C) of the laser light (L) is positioned on the line (M3) and also positioned at a predetermined depth (position in the Z direction) from the first surface (11a) of the object (11). In that state, the control unit (6) controls the movable unit (4) to rotate the stage (2) with an axis parallel to the Z direction as the axis of rotation, and simultaneously controls the light source (31) to start irradiating the laser light (L) and move the irradiation spot (C) of the laser light (L) relative to the object (11). By this, a modified area (12) in the shape of a circular ring is formed along the circular line (M3) on the side opposite to the laser light incident surface (second surface (11b) side) from the virtual surface (M1) inside the object (11). Process S101 is performed multiple times while sequentially changing the position of the light-gathering spot (C) in the Z direction, for example, from the second surface (11b) side to the first surface (11a) side.

[0042] Next, a peeling process is performed. That is, as shown in FIG. 5, a laser beam (L) is irradiated onto the object (11) along the virtual plane (M1) to form a modified area (12) along the virtual plane (M1) (Process S102: first processing treatment, processing process). Process S102 will be explained in more detail. As shown in FIG. 5 (a), a line (A) is set along the virtual plane (M1) on the object (11) when viewed from the Z direction. The line (A) runs in a spiral shape (involute curve) centered on the position of the rotation axis of the stage (2), extending from the periphery edge of the object (11) to the center when viewed from the Z direction.

[0043] As illustrated in FIG. 6, in process S102, the irradiation unit (3) and / or stage (2) are moved so that the laser light (L) concentration spot (C) is positioned on line (A) and also at the depth (position in the Z direction) of the virtual plane (M1) which is the surface to be peeled from the first surface (11a) of the object (11). At this time, the control unit (6) positions the laser light (L) concentration spot (C) at the beginning (e.g., the end on the perimeter edge side) or the end (e.g., the end on the center side) of line (A) when viewed from the Z direction. In that state, the control unit (6) controls the moving unit (4) to rotate the stage (2) with an axis parallel to the Z direction as the axis of rotation, and controls the moving unit (5) to move the irradiation unit (3) along the Y direction intersecting the Z direction, and controls the light source (31) to start irradiating the laser light (L) and move the focused spot (C) of the laser light (L) relative to the object (11).

[0044] At this time, the control unit (6) can adjust the rotation speed of the stage (2) and the movement speed of the irradiation unit (3) in the Y direction so that the light-gathering spot (C) moves relative to the spiral-shaped line (A) when viewed from the Z direction. By doing so, the light-gathering spot (C) of the laser light (L) is moved relative to the tangential direction of the line (A) that intersects the Z direction, and is also moved relative to the first Y direction (e.g., Y plus direction) (ND) that intersects the tangential direction and moves from one side to the other in the Y direction. As a result, a first modification area (121) is formed as a modification area (12) along the line (A) and the virtual plane (M1). Here, the tangential direction of the line (A) is set to the X direction, which is the processing progress direction (PD) along the virtual plane (M1) (see FIG. 5 (a)). In this case, the first modification region (121) is formed in multiple numbers so as to be arranged in the Y direction within the YZ plane, which includes the Z direction and the Y direction intersecting the X direction and the Y direction.

[0045] That is, in process S102, the control unit (6) performs an X-direction processing to form a first modification area (121) arranged along the Y-direction within a YZ plane that includes the Z-direction and Y-direction intersecting the X-direction and Y-direction by moving a light-gathering spot (C) in the X-direction along the virtual plane (M1) and irradiating a laser light (L) onto an object (11) while moving a light-gathering spot (C) in the X-direction along the virtual plane (M1) and changing the position of the light-gathering spot (C) in the Y-direction intersecting the X-direction to a first Y-direction (ND) that extends from one side of the Y-direction to the other, thereby performing the X-direction processing to form a plurality of first modification areas (121) arranged along the Y-direction within a YZ plane that includes the Z-direction and Y-direction intersecting the X-direction and Y-direction.

[0046] In particular, in process S102, the control unit (6) irradiates a laser beam (L) onto an object (11) while moving a concentrating spot (C) along a spiral-shaped line (A), thereby performing an X-direction processing from the beginning to the end of the line (A) to form a first modification area (121) along the X-direction which is the tangential direction of the line (A), and thereby forming a plurality of first modification areas (121) arranged along the Y-direction which is the direction intersecting the tangential direction of the line (A) within the YZ plane.

[0047] FIG. 7 is a drawing showing an example of an object illustrated in FIG. 5 and FIG. 6. FIG. 7 (a) is a perspective view with a portion cut away, and FIG. 7 (b) is a schematic cross-sectional view. As shown in FIG. 7, the object (11) is, for example, a crystal orientation <100> It is a wafer (e.g., a silicon wafer). That is, in the object (11), the first surface (11a) (main surface) is the (100) surface. The object (11) is supported on a stage (2) such that the first surface (11a) becomes the incident surface of the laser light (L). The object (11) includes a (110) surface that is orthogonal to the first surface (11a), which is the (100) surface, and a (111) surface that intersects the (110) surface at an angle of 125.25°. The angle between the (111) surfaces extending in the direction of mutual intersecting is 70.5°.

[0048] FIG. 8 is a cross-sectional view showing an example of the formation of a modified area and a crack in the object shown in FIG. 7. As shown in FIG. 8 (a), when a plurality of modified areas (12) are formed along the Y direction (i.e., the (100) plane) within the YZ plane by irradiating the object (11) with a laser light (L) using the first plane (11a), which is the (100) plane, as the incident plane of the laser light (L), it is preferable to also advance the crack (13) extending from the modified area (12) along the Y direction (i.e., the (100) plane). This is because if the crack (13) extending from the modified area (12) advances obliquely with respect to the (100) plane and reaches, for example, the second plane (11b), there is a risk of adversely affecting the device layer formed on the second plane (11b) or other objects that can be bonded to the second plane (11b) side through the device layer.

[0049] However, the object (11) includes a plane (111) that is easier to cleave than the plane (100). Therefore, as shown in FIG. 8 (b), in practice, when a laser beam (L) is irradiated onto the object (11) with the first plane (11a), which is the plane (100), as the incident plane of the laser beam (L), thereby forming a plurality of modified regions (12) arranged along the Y direction (i.e., the plane (100)) within the YZ plane, cracks (13) extending from the modified regions (12) tend to advance along the plane (111). In this case, there is a risk that the cracks (13) will reach the second plane (11b). Therefore, there is a need to suppress the progression of cracks (13) extending from the modified regions (12) to the second plane (11b).

[0050] Here, as illustrated in FIG. 9 and FIG. 10, among the cracks (13) extending along the (111) plane, the crack (13p) extending from the last modified region (12p) formed among the plurality of modified regions (12) formed to be arranged along the Y direction within the YZ plane tends to advance further. In the example illustrated in FIG. 9, the focused spot (C) of the laser light (L) is moved in the Y-plus direction from the center in the Y direction of the object (11) toward the periphery edge. That is, in the example of FIG. 9, the first Y direction (ND) is the Y-plus direction, and the crack (13p) extending from the modified region (12p) at the end of the first Y direction (ND) (at the periphery edge side of the object (11)) tends to advance further along the (111) plane.

[0051] Meanwhile, in the example illustrated in FIG. 10, the focused spot (C) of the laser light (L) is moved in the Y-negative direction from the periphery edge in the Y direction of the object (11) toward the center. That is, in the example of FIG. 10, the first Y direction (ND) is the Y-negative direction, and the crack (13p) extending from the modified area (12p) at the end of the first Y direction (ND) (the most central side of the object (11)) tends to advance further along the (111) plane.

[0052] As described above, the (111) planes that influence the progression of the crack (13) exist within the object (11) such that they intersect each other at an angle of 70.5°. Accordingly, the crack (13p) that progresses further toward the first Y direction (ND) with respect to the Z direction may extend toward the first plane (11a) side (hereinafter referred to as the "incident plane side" for convenience) along one of the intersecting (111) planes, and may extend toward the second plane (11b) side (hereinafter referred to as the "bottom plane side" for convenience) along the other of the intersecting (111) planes. And, as described above, since there is a risk that the crack (13) will have an adverse effect on the device layer, etc. when it reaches the second plane (11b), it is important to suppress the progression of the crack (13p) that extends toward the bottom plane side along the (111) plane among these cracks (13p).

[0053] In this regard, by adjusting the beam shape at the focusing spot (C) of the laser light (L), the direction of propagation of the crack (13) extending from the modification area (12) can be controlled. In the example shown in FIG. 11 (a), the beam shape at the focusing spot (C) of the laser light (L) within the YZ plane is inclined in the Y-negative direction with respect to the Z direction, with respect to the incident plane side rather than the center (Ca) of the focusing spot (C) (here, it is shaped like an arc that is convex in the Y-positive direction overall). When the beam shape at the focusing spot (C) of the laser light (L) is adjusted to such a shape, as shown in FIG. 11 (b), the crack (13) extending from the modified region (12a, 12b) formed by the irradiation of such laser light (L) becomes a crack (13a) that extends obliquely in the same direction as the inclination direction of the beam shape on the incident plane side rather than the center (Ca) of the focusing spot (C) (here, the Y minus direction).

[0054] Additionally, the beam shape shown in FIG. 11 (a) can be formed, for example, by controlling the spatial light modulator (7) to offset the center of the spherical aberration correction pattern in the spatial light modulator (7) in an inclined direction with respect to the center of the incident plane of the condensing lens (33), or by controlling the magnitude of the coma aberration in the coma aberration pattern for imparting coma aberration to the laser light (L).

[0055] Accordingly, when forming a plurality of modified regions (12) arranged in the Y direction including the modified region (12p), it is possible to suppress the progression of the crack (13p) by adjusting the beam shape of the laser light (L)'s focusing spot (C) so that the inclination direction of the crack (13a) with respect to the Z direction becomes opposite to the inclination direction of the crack (13p) with respect to the Z direction.

[0056] More specifically, when forming a modified region (12p), if the inclination direction of the part on the incident plane side relative to the center (Ca) of the beam shape at the concentrating spot (C) of the laser light (L) is adjusted such that the inclination direction relative to the Z direction of the crack (13a) formed by irradiation of a laser light (L) is opposite to the inclination direction relative to the Z direction of the crack (13p) extending toward the bottom side, the progression of the crack (13p) can be suppressed.

[0057] In the example of FIG. 9, if the inclination direction with respect to the Z direction of the crack (13a) that can be formed by irradiation of the laser light (L) is adjusted so that the inclination direction of the part of the beam shape on the incident plane side, which is closer to the center (Ca) of the laser light (L) at the focusing spot (C), is also adjusted so that the inclination direction is the first Y direction (ND) which is the Y-plus direction, then the progression of the crack (13p) extending obliquely from the modified area (12p) toward the bottom side can be suppressed. In addition, in the example of FIG. 10, if the inclination direction with respect to the Z direction of the crack (13a) that can be formed by irradiation of the laser light (L) is adjusted so that the inclination direction of the part on the incident plane side rather than the center (Ca) of the beam shape in the laser light (L) is also adjusted so that the inclination direction is the first Y direction (ND) that is the Y direction, then the progression of the crack (13p) extending obliquely from the modified area (12p) toward the bottom side can be suppressed.

[0058] That is, by modulating the laser light (L) by the spatial light modulator (7) such that the beam shape at the focusing spot (C) of the laser light (L) is inclined toward the first Y direction (ND) with respect to the Z direction at least on the incident plane side than the center (Ca) of the focusing spot (C), the progression of the crack (13p) extending obliquely from the modified area (12p) toward the bottom side can be suppressed.

[0059] FIG. 12 is a diagram showing the relationship between each beam shape and processing result when the first Y direction (ND) is the Y-plus direction. In the example shown in FIG. 12, the processing result is shown when the offset amount of the spherical aberration correction pattern in the spatial light modulator (7) is varied from -15 to +5. When the offset amount is negative, the part of the beam shape on the incident plane side, relative to the center (Ca) of the beam shape at the collecting spot (C) of the laser light (L), is inclined toward the first Y direction (ND), which is the Y-plus direction with respect to the Z direction, and when the offset amount is positive, the corresponding part is inclined toward the direction opposite to the first Y direction (ND) (i.e., the direction of inclination of the crack (13p) extending toward the bottom side).

[0060] Referring to FIG. 12, it is understood that when the inclination direction with respect to the Z direction of the part of the incident plane side relative to the center (Ca) of the beam shape at the focusing spot (C) of the laser light (L) is the first Y direction (ND) (i.e., when the offset amount is negative), the progression of the crack (13p) extending toward the bottom side is suppressed as described above. On the other hand, when the offset amount is 0 and when the offset amount is positive, the progression of the crack (13p) extending toward the bottom side is not suppressed.

[0061] From the above perspective, in process S102 (i.e., in the first processing step), the control unit (6) modulates the laser light (L) by the spatial light modulator (7) such that the beam shape at the focusing spot (C) of the laser light (L) in the YZ plane is inclined toward the first Y direction (ND) with respect to the Z direction at least from the center (Ca) of the focusing spot (C) toward the incident plane.

[0062] In addition, to suppress the progression of cracks (13p) extending toward the bottom side, the laser light (L) may be modulated by a spatial light modulator (7) so that the entire beam shape at the focusing spot (C) of the laser light (L) in the YZ plane is inclined toward the first Y direction (ND), as shown in FIG. 13. FIG. 13 (a) shows the beam shape in the YZ plane, and FIG. 13 (b) shows the beam shape (intensity distribution) in each cross section (i.e., the XY plane) of F1 to F7 in FIG. 13 (a). Each figure in FIG. 13 (b) is the result of actual observation by a camera. According to FIG. 13, as the position in the Z direction changes from F1 to F7, it can be understood that the focusing spot (C) gradually shifts toward one side of the Y direction (here, the first Y direction (ND) side, which is the Y-plus direction).

[0063] In addition, in the case of the arc-shaped beam shape shown in FIG. 11, within the XY plane, as the position in the Z direction moves from the incident plane side to the center (Ca), the light-gathering spot (C) gradually shifts toward one side of the Y direction, and as the position in the Z direction moves from the center (Ca) to the lower plane side, the light-gathering spot (C) gradually shifts toward the other side of the Y direction.

[0064] As described above, in the laser processing method according to the present embodiment, trimming is performed in process S101 and peeling is performed in process S102. By doing so, as shown in FIG. 14 (a), a portion of the object (11) can be peeled off along the boundary of the modified area (12) formed across the virtual plane (M1) and the crack (13) extending from the modified area (12). Along with this, the removal area (E) can be removed along the boundary of the modified area (12) formed along the line (M3) and the crack (13) extending from the modified area (12). Afterward, for example, as shown in FIG. 13 (b), finishing polishing or polishing with an abrasive such as a grinding stone can be performed on the peeled surface (11h) of the object (11). As a result of the above, a semiconductor device (11k) is obtained from the object (11).

[0065] As described above, in the laser processing device (1) and laser processing method according to the present embodiment, within a virtual plane (M1) along the incident plane (first plane (11a)) of the laser light (L) of the object (11), by irradiating the laser light (L) while moving the focusing spot (C) along the virtual plane (M1) to form a first modification area (121) along the X direction, the X direction processing is performed by changing the position of the focusing spot (C) in the Y direction that intersects the X direction along the virtual plane (M1) to a first Y direction (ND) that is directed from one side of the Y direction to the other, thereby forming a plurality of first modification areas (121) arranged along the Y direction within the YZ plane.

[0066] In particular, in the laser processing device (1) and laser processing method according to the present embodiment, when forming the first modification area (121), the beam shape of the laser light (L) at the focusing spot (C) in the YZ plane is inclined toward the first Y direction (ND) at least from the center (Ca) of the focusing spot (C) toward the incident plane. By using the focusing spot (C) having such a beam shape when forming the first modification area (121), the crack (13) extending from the first modification area (121) toward the first Y direction (ND) is suppressed from advancing obliquely toward the bottom side of the object (11). That is, it is possible to suppress the advancement of the crack (13) extending from the first modification area (121).

[0067] In addition, in the laser processing device (1) and laser processing method according to the present embodiment, in process S102, the control unit (6) irradiates a laser beam (L) onto an object (11) while moving a focusing spot (C) along a spiral-shaped line (A), thereby performing X-direction processing from the beginning to the end of the line (A) to form a first modification area (121) along the X-direction, which is the tangential direction of the line (A), thereby forming a plurality of first modification areas (121) arranged along the Y-direction, which is the direction intersecting the tangential direction of the line (A) within the YZ plane. In this way, the first processing treatment may be performed along the line (A) set in a spiral shape on the object (11) (i.e., spiral processing may be performed). When spiral processing is performed, it is possible to perform processing continuously along a single line (A). For this reason, it is possible to improve the tact, and since the effect of the rise when the laser is ON is limited to only one point at the processing start point, stable processing is possible.

[0068] In addition, in the laser processing device (1) and laser processing method according to the present embodiment, the object (11) has an effective area (R) (first area) including the center of the object when viewed from the Z direction, and a removal area (E) (second area) including the periphery edge of the object (11) as an area outside the effective area (R). Then, the control unit (6) performs a first processing treatment on the effective area (R). By doing so, it becomes possible to perform a peeling process using a first modified area (121) formed along a virtual plane (M1) while suppressing the progression of cracks (13) in the effective area (R) including the center of the object (11). In particular, since the progression of cracks extending from the first modified area (121) formed along the virtual plane (M1) is suppressed, the roughening of the peeling surface is suppressed, and the quality of the peeling surface is improved.

[0069] [Second Embodiment]

[0070] Next, a laser processing method according to a second embodiment will be described. As shown in FIG. 15, the object (100) of the laser processing according to the present embodiment includes the object (11) described above and an object (11R) which is a different component from the object (11). The object (11R) is, for example, a silicon wafer. The object (11) includes a plurality of functional elements and a device layer (110) formed on a second surface (11b). The object (11R) includes a plurality of functional elements and a device layer (110R) formed on a first surface (11Ra) of the object (11R). The object (11) and the object (11R) are stacked by arranging the device layer (110) and the device layer (110R) to face each other and joining them together, thereby constituting the object (100).

[0071] The effective area (R) (first area) and the removal area (E) (second area) of the object (11) have a boundary (B). In this embodiment, the boundary (B) is also a trimming planned line. Additionally, in the removal area (E) of the object (11), a virtual surface (M2) is set as a planned peeling surface. The virtual surface (M2) is a surface planned for the formation of the modification area (12). The virtual surface (M2) is a surface that follows the first surface (11a), which is the laser light incident surface of the object (11). The virtual surface (M2) is a surface parallel to the first surface (11a) and, for example, represents a round ring shape. The virtual surface (M2) is a virtual area and is not limited to a flat plane, but may be a curved surface or a three-dimensional surface. The setting of the virtual surface (M2) can be performed by the control unit (6). The virtual surface (M2) may be a coordinate-specified surface.

[0072] The laser processing method according to the present embodiment is carried out by the laser processing device (1) described above. Accordingly, the laser processing method described below is also an example of processing performed by the laser processing device (1). That is, here, the control unit (6) controls the moving unit (4, 5) to move at least one of the stage (2) and the irradiation unit (3), thereby moving the focused spot (C) of the laser light (L) relative to the object (11) and irradiating the laser light (L) onto the object (11), thereby performing laser processing to form a modified area (12) on the object (11).

[0073] In the laser processing method according to the present embodiment, a peeling process is first performed. That is, as shown in FIG. 15, a laser beam (L) is irradiated onto an object (11) along a virtual plane (M2) to form a modified area (12) along the virtual plane (M2) (Process S201: first processing treatment, processing process). Process S201 will be explained in more detail. As shown in FIG. 15 (a), a plurality of circular lines (A) are set along the virtual plane (M2) on the object (11) when viewed from the Z direction. The plurality of lines (A) are arranged in a concentric circle shape that shares a center with the object (11) when viewed from the Z direction.

[0074] In process S201, as illustrated in FIGS. 15 and FIGS. 16 (a), the control unit (6) controls the moving unit (4, 5) so that the laser light (L) concentration spot (C) is positioned on one of the multiple lines (A) and also positioned at the depth (position in the Z direction) of the virtual plane (M2) which is the surface to be peeled from the first surface (11a) of the object (11) and the irradiation unit (3) and / or the stage (2) are moved. In that state, the control unit (6) controls the moving unit (4) to rotate the stage (2) with an axis parallel to the Z direction as the axis of rotation, and at the same time, by controlling the light source (31), the irradiation of the laser light (L) is started and the laser light (L) concentration spot (C) (concentration spot (C0)) is moved relative to the object (11). By this, as shown in FIG. 16 (b), a first modification region (121) arranged in a circular shape is formed as a modification region (12) in a circular line (A) viewed from the Z direction. Also, in this example, the one line (A) and the boundary (B) coincide.

[0075] In process S201, as shown in FIG. 17, the formation of the first modified region (121) is repeated while sequentially changing the position in the Y direction. That is, the control unit (6) performs a first processing operation to form a plurality of first processing areas (121) arranged along the Y direction within a YZ plane that includes the Z direction and Y direction intersecting the X direction and the Y direction, by irradiating a laser light (L) onto an object (11) while moving a light-gathering spot (C0) in the X direction along the virtual plane (M2) to form a first processing area (121) as a processing area (12) along the X direction, and by changing the position of the light-gathering spot (C0) in the Y direction intersecting the X direction along the virtual plane (M2) to a first Y direction (ND) (here, a Y plus direction from the center side of the object (11) toward the periphery edge side) while changing the position of the light-gathering spot (C0) in the Y direction intersecting the X direction and the X direction to a first Y direction (ND) (here, a Y plus direction from the center side of the object (11) toward the periphery edge side).

[0076] In particular, in process S201, the control unit (6) irradiates a laser light (L) onto an object (11) while moving a light-gathering spot (C) along a line (A) to form a first modification area (121) along the X direction as the circumferential direction of the line (A), and performs X-direction processing over a plurality of lines (A) while changing the line (A) to the first Y direction (ND), thereby forming a plurality of first modification areas (121) arranged along the Y direction as the diameter direction of the line (A) within the YZ plane. By doing so, a plurality of first modification areas (121) arranged in a two-dimensional shape within a virtual plane (M2) are formed.

[0077] In this way, in process S201, a plurality of modified regions (12) arranged in the Y direction within the YZ plane are formed, just as in the first embodiment. Accordingly, in this embodiment as in the first embodiment, there is a requirement to suppress the progression of cracks (13) extending from the modified regions (12) toward the bottom side along the (111) plane. Accordingly, in process S201, just as in process S102 according to the first embodiment, the control unit (6) modulates the laser light (L) by the spatial light modulator (7) so that the beam shape at the focusing spot (C) of the laser light (L) within the YZ plane is inclined toward the first Y direction (ND) with respect to the Z direction at least from the center (Ca) of the focusing spot (C) toward the incident plane side. By the above, the peeling process is completed.

[0078] In the subsequent process, trimming is performed. As described above, the effective area (R) and the removal area (E) have a boundary (B), and the boundary (B) is also a trimming line. That is, in the subsequent process, as shown in FIG. 18, a laser beam (L) is irradiated at the boundary (B) to form a modified area (12) (process S202, second processing). More specifically, in process S202, first, the irradiation unit (3) and / or the stage (2) are moved so that the laser beam (L) concentration spot (C) is located at the boundary (B) and also at a predetermined depth (position in the Z direction) from the first surface (11a) of the object (11).

[0079] In that state, the control unit (6) controls the moving unit (4) to rotate the stage (2) with an axis parallel to the Z direction as the axis of rotation, and simultaneously controls the light source (31) to initiate irradiation of the laser light (L) and to move the focused spot (C) of the laser light (L) relative to the object (11). By doing so, a modified area (12) arranged in a circular shape is formed at the circular boundary (B) when viewed from the Z direction.

[0080] At this time, as shown in FIG. 19 (a), the control unit (6) modulates the laser light (L) by controlling the spatial light modulator (7) so that a laser light spot (C1) in the Z direction is formed as a laser light spot (C), compared with the laser light spot (C0) formed when the first modification area (121) is formed in process S201, thereby imparting a first aberration to the laser light (L). By doing so, as shown in FIG. 19 (b), a third modification area (123) in the Z direction can be formed as a modification area (12) (and a second modification area (122) described later) at the boundary (B). That is, in process S202, the control unit (6) performs a process of irradiating laser light (L) onto the object (11) so as to form a third modification area (123) in the Z direction as a modification area (12) at the boundary (B) between the effective area (R) and the removal area (E).

[0081] The first aberration imparted to the laser light in process S202 is described. FIG. 20 is a diagram illustrating the aberration occurring at the focusing position of the laser light. When the laser light (L) is a plane wave (a plane wavefront (phase)), it is geometrically focused at a single point. On the other hand, since the wavefront of the laser light (L) of a plane wave usually changes due to various influences, there are cases where the laser light (L) focused on the object (11) does not focus at a single point, i.e., aberration occurs naturally. The aberration includes, for example, Seidel aberration (astigmatism, coma aberration, spherical aberration, image plane curvature and distortion aberration), and also includes longitudinal aberration, which is an aberration in the longitudinal direction (a direction following the optical axis direction), and transverse aberration, which is an aberration in a direction intersecting the longitudinal direction.

[0082] For example, as illustrated in FIG. 20, when a laser beam (L) is focused onto an object (11) by a focusing lens (33) or the like, when it is incident on the object (11) during the focusing process, spherical aberration naturally occurs in which light rays of different angles of incidence are focused at different locations due to refraction (Snell's Law). That is, as illustrated, due to the laser beam (L) being focused onto the object (11), aberration naturally occurs at the corresponding focusing location without relying on the spatial light modulator (7), and a range of aberration along the optical axis direction (a range in which the intensity of the corresponding laser beam (L) is greater than or equal to the processing threshold value (α)) exists as a reference aberration (H).

[0083] By modulating the laser light (L) containing such a reference aberration (H) using a spatial light modulator (7), it becomes possible to impart an aberration different from the reference aberration (H) to the laser light (L). FIG. 21 is a diagram showing the intensity and focusing spot of the laser light when multiple aberrations are imparted based on the reference aberration. The intensity distributions D10, D11, D12, and D13 shown in FIG. 21 represent, in order, the case where a reference aberration H10 corresponding to the reference aberration (H) is imparted, the case where a first aberration H11 with a longer range (negative side) than the reference aberration H10 is imparted, the case where a first aberration H12 with a longer range (more negative side) than the reference aberration H10 is imparted, and the case where a second aberration H13 with a shorter range (positive side) than the reference aberration H10 is imparted. In addition, the concentrating spots C10, C11, C12, and C13 are, for example, regions that are greater than or equal to the processing threshold (α) for each of the corresponding intensity distributions D10, D11, D12, and D13.

[0084] As illustrated in FIG. 21, the control unit (6) can impart a first aberration H11 and H12 to the laser light (L) by controlling the spatial light modulator (7) to modulate the laser light (L), so that a long, narrow-shaped focusing spot C11 and C12 are formed in the Z direction, compared to the focusing spot C10 of the laser light (L) to which a reference aberration H10 is imparted. Examples of such modulation include, for instance, phase modulation that realizes the action of an axicon lens, phase modulation that realizes the action of a diffraction grating, and phase modulation that generates a predetermined spherical aberration. Each of the examples of such phase modulation can be implemented, for instance, by displaying an axicon lens pattern, a diffraction grating pattern, and a predetermined spherical aberration pattern, respectively, as modulation patterns to the spatial light modulator (7).

[0085] As described above, in process S202, the control unit (6) controls the spatial light modulator (7) to modulate the laser light (L) so that when the aberration occurring in the direction of the optical axis of the laser light (L) at the corresponding focusing position is set as a reference aberration H10, the laser light (L) is given a reference aberration H10, and the focusing spots C11 and C12 are formed in the Z direction more elongated than the focusing spot C10 of the laser light (L) to which the reference aberration H10 is given, thereby giving the first aberration H11 and H12 to the laser light (L). By doing so, as shown in FIG. 19 (b), a third modified region (123) in the Z direction is formed as a second modified region (122) at the boundary (B).

[0086] It has been confirmed that the third modified region (123), formed in this manner, has a property that makes it difficult for cracks extending from the third modified region (123) to advance in the Z direction (i.e., the cracks become shorter) compared to the modified region (12) formed by a laser light (L) to which, for example, a reference aberration H10 or a second aberration H13 is applied. By this, when the third modified region (123) is formed near another modified region (12), it has the effect of suppressing the cracks extending from the third modified region (123) from connecting to cracks extending from the other modified region (12) and causing further advancement. In other words, as described above, by making the second modification area (122) formed near the first modification area (121) where the progression of the crack (13) extending along the (111) plane is predicted to be such a third modification area (123), it is possible to suppress the progression of the crack (13) extending from the first modification area (121) so that it does not reach the second plane (11b).

[0087] In process S202, as illustrated in FIG. 22, laser processing is performed to form a plurality of second modification regions (122) arranged in the Z direction along the boundary (B) within the YZ plane as modification regions (12) (Process S202: Second processing). More specifically, first, the irradiation unit (3) and / or stage (2) are moved so that the focusing spot (C2) of the laser light (L) is located at the boundary (B) and also at a predetermined depth (position in the Z direction) from the first surface (11a) of the object (11). At this time, as illustrated in FIG. 22 (a), the position in the Z direction of the focusing spot (C2) is positioned closer to the incident surface of the laser light (L) than the position in the Z direction of the focusing spot (C1) when the third modification region (123) is formed.

[0088] In that state, the control unit (6) controls the moving unit (4) to rotate the stage (2) with an axis parallel to the Z direction as the axis of rotation, and simultaneously controls the light source (31) to initiate irradiation of the laser light (L) and to move the laser light (L) concentration spot (C2) relative to the object (11). At this time, the concentration spot (C2) becomes a concentration spot (C2) that is shorter in the Z direction than the concentration spot (C1) when the third modification area (123) is formed. By this, as shown in FIG. 22 (b), a second modification area (122) arranged in a circular shape is formed as a modification area (12) at the circular boundary (B) viewed from the Z direction.

[0089] The formation of this second modified region (122) is performed multiple times while sequentially changing the position of the Z-direction of the concentrating spot (C2) from the bottom side toward the incident side. By doing so, a plurality of second modified regions (122) arranged along the Z-direction at the boundary (B) within the YZ plane are formed as modified regions (12). Thus, in process S202, the control unit (6) performs a second processing process after the first processing process to form a plurality of second modified regions (122) as modified regions (122) that have a positional relationship intersecting with a plurality of first modified regions (121) arranged along the Y-direction at the boundary (B) (including a third modified region (123)).

[0090] Additionally, the intersecting positional relationship is a positional relationship in which a virtual line (plane) connecting a plurality of first modification regions and a virtual line (plane) connecting a plurality of second modification regions (122) intersect each other, and there are cases where the plurality of first modification regions (121) and the plurality of second modification regions (122) actually intersect, and cases where they do not intersect (for example, a gap is formed in the Z direction).

[0091] Among the plurality of second modification regions (122), the aforementioned long-length third modification region (123) is the second modification region (122) that is closest to the first modification region (121) and is also located on the bottom side. In this embodiment, the third modification region (123) is closest to the first modification region (121) located at the end of the first Y direction (ND) among the plurality of first modification regions (121) (i.e., the first modification region (121) that was last formed in process S201). In this way, in process S202, the control unit (6) modulates the laser light (L) by controlling the spatial light modulator (7) so that the third modification region (123), which is the second modification region (122) closest to the first modification region (121) among the plurality of second modification regions (122), becomes elongated in the Z direction, thereby imparting the first aberrations H11 and H12 to the laser light (L).

[0092] As a result of this process S202, a crack (13) is formed at the boundary (B) that extends across a plurality of second modified regions (122) including a third modified region (123). The crack (13) may extend to the first surface (11a).

[0093] As described above, in the laser processing method according to the present embodiment, peeling processing is performed in process S201 and trimming processing is performed in process S202. By doing so, a part of the object (11) (removal area (E)) can be peeled off with respect to the modified area (12) formed across the virtual plane (M2) and the crack (13) extending from the modified area (12), and the modified area formed along the boundary (B) and the crack (13) extending from the modified area (12).

[0094] As described above, in the laser processing device (1) and laser processing method according to the present embodiment, within a virtual plane (M2) along the incident plane (first plane (11a)) of the laser light (L) of the object (11), by irradiating the laser light (L) while moving a focusing spot (C) (focusing spot (C0)) along the virtual plane (M2) to form a first modification area (121) along the X direction, the X direction processing is performed by changing the position of the focusing spot (C) in the Y direction that intersects the X direction along the virtual plane (M2) to a first Y direction (ND) that is directed from one side of the Y direction to the other, thereby forming a plurality of first modification areas (121) arranged along the Y direction within the YZ plane.

[0095] In particular, in the laser processing device (1) and laser processing method according to the present embodiment, when forming the first modification area (121), the beam shape of the laser light (L) at the focusing spot (C) in the YZ plane is inclined toward the first Y direction (ND) at least from the center (Ca) of the focusing spot (C) toward the incident plane. By using the focusing spot (C) having such a beam shape when forming the first modification area (121), the crack (13) extending from the first modification area (121) toward the first Y direction (ND) is suppressed from advancing obliquely toward the bottom side of the object (11). That is, it is possible to suppress the advancement of the crack (13) extending from the first modification area (121).

[0096] In addition, in the laser processing device (1) and laser processing method according to the present embodiment, a plurality of lines (A) arranged in a concentric circle shape when viewed from the Z direction are set on the object (11), and in process S201, the control unit (6) irradiates the object (11) with a laser light (L) while moving a focusing spot (C) along one line (A) to form a first modification area (121) along the X direction, which is the circumferential direction of the one line (A), and performs X-direction processing across the plurality of lines (A) while changing the one line (A) to the first Y direction (ND), thereby forming a plurality of first modification areas (121) arranged along the Y direction, which is the diameter direction of the line (A), within the YZ plane (virtual plane (M2)). Thus, the first processing treatment may be performed along the plurality of lines (A) set in a concentric circle shape on the object (11) (i.e., concentric processing may be performed). When concentric processing is performed, unlike when spiral processing is performed, the spacing in the Y direction of the first modified region (121) within the YZ plane can be kept constant, so stable processing is possible.

[0097] In addition, in the laser processing device (1) and laser processing method according to the present embodiment, the object (11) has an effective area (R) (first area) including the center of the object (11) when viewed from the Z direction, and a removal area (E) (second area) including the periphery edge portion of the object (11) as an area outside the effective area (R). Then, the control unit (6) performs a first processing treatment on the removal area (E). By doing so, it becomes possible to perform a peeling process using a first modified area (121) formed along a virtual plane (M2) in the removal area (E) including the periphery edge portion of the object (11) while suppressing the progression of cracks (13). In particular, since the progression of cracks extending from the first modified area (121) formed along the virtual plane (M2) is suppressed, the roughening of the peeling surface is suppressed, and the quality of the peeling surface is improved.

[0098] In addition, in the laser processing device (1) and laser processing method according to the present embodiment, the control unit (6) performs a second processing process after the first processing process, in which a plurality of second modification regions (122) are formed as modification regions (12) that have a positional relationship intersecting a plurality of first modification regions (121) arranged along the Y direction at the boundary (B). In the second processing process (process S202), the control unit (6) modulates the laser light (L) by controlling the spatial light modulator (7) so that the third modification region (123), which is the second modification region (122) closest to the first modification region (121) among the plurality of second modification regions (122), becomes elongated in the Z direction, thereby imparting a first aberration H11, H12 to the laser light (L). The third modification region (123) is the second modification region (122) furthest from the incident plane among the plurality of second modification regions (122), and the first aberrations H11 and H12 are aberrations for forming a long, narrow shape of the focusing spot C11 and C12 in the Z direction, which is greater than the focusing spot C10 of the laser light (L) to which the reference aberration H10 is applied, when the aberration occurring in the direction of the optical axis of the laser light (L) at the focusing position due to focusing the laser light (L) on the object (11) is set as the reference aberration H10.

[0099] The third modified region (123) formed in this manner has the property that cracks extending from the third modified region (123) are difficult to advance in the Z direction (i.e., the cracks become short). Because of this, since it is difficult for cracks to extend from the third modified region (123), the advancement of cracks (13) from the third modified region (123) to the bottom surface (second surface (11b)) of the object (11) is suppressed. Furthermore, in this case, the second modified region (122) closest to the first modified region (121) is the third modified region (123) where cracks are difficult to extend. In this case, due to the formation of the third modified region (123), it is difficult for the phenomenon of additional advancement of cracks (13) extending from the first modified region (121) to occur. That is, the progression of the crack (13) from the first modified area (121) to the bottom surface of the object (11) is suppressed. As described above, in this case, it is possible to reliably suppress the progression of the crack (13) extending from the modified area (12).

[0100] [Variation Example]

[0101] The above embodiments describe one aspect of the laser processing apparatus and laser processing method according to the present disclosure. Accordingly, the laser processing apparatus and laser processing method according to the present disclosure are not limited to the above embodiments and can be modified arbitrarily. Modified examples will be described next.

[0102] FIG. 23 is a drawing for explaining a laser processing method according to a modified example. As shown in FIG. 23, the boundary (B) between the effective area (R) and the removal area (E) may include an inclined portion (B1) that is inclined with respect to the Z direction within the YZ plane. In the example of FIG. 23 (a), a part of the boundary (B) on the second plane (11b) side is the inclined portion (B1). In the example of FIG. 23 (b), the entire boundary (B) is the inclined portion (B1). Thus, when the boundary (B) includes the inclined portion (B1), when forming the modification area (12) in the inclined portion (B1), there is a requirement to form a crack (13) that extends obliquely along the inclined portion (B1) (with respect to the Z direction) from the modification area (12).

[0103] Thus, the control unit (6) can modulate the laser light (L) by controlling the spatial light modulator (7) so that when forming a modified region (12) in the inclined section (B1) as shown in FIG. 11 (in the example shown, process S202, second processing), the beam shape of the laser light (L) at the focusing spot (C) in the YZ plane is inclined in the inclined direction of the inclined section (B1) (here, Y minus direction) at least on the side of the incident plane (first plane (11a)) rather than the center (Ca) of the focusing spot (C).

[0104] Various methods can be conceived as modulation methods for such laser light (L), and any method can be selected. For example, methods such as offsetting the center of a spherical aberration correction pattern in an inclined direction with respect to the center of the incident plane of the condensing lens (33) as described above, or controlling the magnitude of coma aberration in a coma aberration pattern for imparting coma aberration to the laser light (L), or modulating the laser light (L) by a modulation pattern that is asymmetric with respect to the axis line along the X direction, which is the processing direction, can be cited.

[0105] By controlling the shape of the light-concentrating spot (C) as described above, as shown in FIG. 24 (a), it is possible to form a third modified region (123) in process S202, and also to form a crack (13a) that extends obliquely along the inclined portion (B1) between the third modified region (123) and the second modified region (122) closest to the third modified region (123). In addition, in the example of FIG. 24 (a), in process S202, the second modified region (122) arranged in the Z direction is formed without inclining the light-concentrating spot (C), thereby forming a crack (13b) that extends in the Z direction from the second modified region (122).

[0106] Meanwhile, in the example of FIG. 24 (b), in process S202, the concentrating spot (C) is inclined, and a plurality of second modified regions (122) and third modified regions (123) are formed along the entire boundary (B) inclined with respect to the Z direction, thereby forming a crack (13a) that extends in an inclined direction with respect to the Z direction along the entire boundary (B). In this way, by forming a crack (13a) that extends obliquely with respect to the Z direction from the modified region (12) along the inclined boundary (B), it is possible to reduce the impact on structures on the bottom side, such as the device layer (110, 110R) or other objects (11R), compared to the case where the crack (13) extending from the modified region (12) advances along the Z direction and reaches the bottom surface (second surface (11b)).

[0107] FIG. 25 is a schematic cross-sectional (XY plane) view for explaining a laser processing method according to another modified example. As shown in FIG. 25 (a), a laser beam (L) can be branched so that a plurality (here, two) of focused spots (C) are formed at different positions in the Y direction intersecting the X direction, which is the processing direction, within virtual planes (M1, M2). The branching of the laser beam (L) can be performed, for example, by displaying a branching pattern such as a diffraction grating pattern on a spatial light modulator (7) and modulating the laser beam (L) by the pattern.

[0108] In the first embodiment, such branching of the laser light (L) can be performed in the first processing step S102, and in the second embodiment, in the first processing step S201. That is, in the first processing step, the control unit (6) can branch the laser light (L) so that a plurality of light-gathering spots (C) with different positions in the Y direction are formed within the virtual planes (M1, M2).

[0109] In this way, by forming a plurality of light-focusing spots (C) with different positions in the Y direction, as shown in FIG. 25 (b) and (c), a plurality (here, two) of first modified regions 121a and 121b with different positions in the Y direction can be formed as modified regions (12) at positions corresponding to each light-focusing spot (C). Additionally, the first modified region 121b is formed after the first modified region 121a. In this way, by forming a plurality of light-focusing spots (C) with different positions in the Y direction through the branching of the laser light (L), the cracks (13) extending from each of the first modified regions 121a and 121b formed corresponding to the plurality of light-focusing spots (C) become easily connected to each other within the XY plane (virtual plane (M1, M2)). As a result, the crack (13) extending from the first modified region 121a, 121b is prevented from advancing obliquely toward the bottom side.

[0110] Additionally, as shown in FIG. 26 (a), the laser light (L) may be branched so that a plurality (here, two) of light-gathering spots (C) are formed at different positions in the X direction and the Y direction intersecting the X direction, which is the processing direction, within the virtual plane (M1, M2). That is, in the first processing step, the control unit (6) may branch the laser light (L) so that a plurality of light-gathering spots (C) at additionally different positions in the X direction are formed within the virtual plane (M1, M2).

[0111] In the illustrated example, as shown in FIG. 26 (b) and (c), one of the first modified regions 121a is arranged in the Y direction when viewed from the Z direction to the first modified region 121b formed after the first modified region 121a. By doing so, cracks (13) are more likely to be connected in the Y direction between the first modified region 121a and the first modified region 121b. As a result, cracks (13) extending from each of the first modified regions 121a and 121b formed corresponding to a plurality of light-concentrating spots (C) are more likely to be connected to each other within the XY plane. Therefore, the oblique progression of cracks (13) extending from the first modified regions 121a and 121b toward the bottom side is more reliably suppressed.

[0112] In addition, as illustrated in FIG. 27 (a), when forming a light-concentrating spot (C) at a different position in the X and Y directions within a virtual plane (M1, M2), the amount of shift in the X direction between one light-concentrating spot (C) and another light-concentrating spot (C) may be made larger. In the illustrated example, as illustrated in FIG. 27 (b), the amount of shift in the X direction of the light-concentrating spot (C) may be larger than the distance between the first modified region 121a and the first modified region 121b formed after the first modified region 121a.

[0113] In this example, the amount of shift in the X direction of the concentrating spot (C) is set such that when the first modified region 121a, the first modified region 121b, the first modified region 121c, and the first modified region 121d are formed sequentially, one first modified region 121a is aligned with the first modified region 121d in the Y direction. By doing so, it is possible to accumulate internal stress in the Y direction when the first modified regions 121a to 121d are formed, thereby making it easier for the crack (13) to propagate along the Y direction.

[0114] In addition, as described above, when the laser light (L) is branched to form a plurality of concentrated spots (C) in the first processing step, the control unit (6) can modulate the laser light (L) by the spatial light modulator (7) such that the beam shape of the laser light (L) at each of the plurality of concentrated spots (C) is inclined toward the first Y direction (ND) with respect to the Z direction at least from the center (Ca) of the concentrated spot (C).

[0115] Although the main variations have been described above, any other variations are possible. For example, in the above embodiment, during the first processing step, while the light-gathering spot (C) rotates along the circular line (A) when viewed from the Z direction, the beam shape was adjusted so that at least the portion on the incident plane side along the entire circumference of the line (A) was inclined toward the first Y direction (ND). However, such adjustment of the beam shape may be performed only on a part of the line (A).

[0116] For example, the object (11) has a determination orientation <100> In a state where the first surface (11a), which is the (100) surface, is supported on the stage (2) so as to face the irradiation unit (3), when viewed from the Z direction, the intersection point of the (110) surface of the object (11) and the line (A) is set to a processing angle of 0° and 180°, and the intersection point of the (100) surface of the object (11) and the line (A) is set to a processing angle of 90° and 270°, then at least, the adjustment of the beam shape may be performed by controlling the modulation pattern displayed on the spatial light modulator (7) only in a portion of the area including each of the processing angles of the line (A) of 0°, 90°, 180°, and 270°. Explanation of the symbols

[0117] 1… Laser processing device 2… Stage (support section) 3… Investigation Department 4, 5… Mobile Department 6… Control unit 7… Spatial optical modulator 11… object 11a… First plane (plane of incidence) 11b… Second side (bottom) 12… modification zone 13, 13a, 13b, 13p… cracks 31… light source 33… Concentrating lens (concentrating part) 121… 1st Reforming Zone 122… 2nd reforming zone 123… Third modification zone L… Laser light H, H10… Reference Water Cycle H11, H12… 1st water turbine

Claims

Claim 1 A laser processing device for forming a modification region along a virtual plane inside an object along the incident plane of the laser light of the object by irradiating the object with laser light, comprising: a support member for supporting the object; an irradiation member for irradiating the laser light onto the object supported by the support member; a moving member for moving at least one of the support member and the irradiation member so that a focused spot of the laser light moves along the virtual plane; and a control member for controlling the support member, the irradiation member, and the moving member. The irradiation member includes a spatial light modulator for modulating the laser light and a focusing member for focusing the laser light that has passed through the spatial light modulator toward the object. The control member performs X-direction processing, wherein, within the virtual plane, the laser light is irradiated onto the object while moving the focused spot in the X-direction along the virtual plane to form a first modification region as the modification region along the X-direction, wherein the position of the focused spot in the Y-direction that follows the virtual plane and intersects the X-direction is from one side of the Y-direction. A laser processing apparatus that performs a first processing process to form a plurality of first modified regions arranged along the Y direction within a YZ plane including a Z direction intersecting the X direction and the Y direction and the Y direction by changing to a first Y direction directed toward the other direction, wherein in the first processing process, the control unit modulates the laser light by the spatial light modulator such that the beam shape at the focusing spot of the laser light within the YZ plane is inclined toward the first Y direction with respect to the Z direction at least on the incident plane side relative to the center of the focusing spot. Claim 2 A laser processing apparatus according to claim 1, wherein a plurality of lines arranged in a concentric circle shape when viewed from the Z direction are set on the object, and the control unit irradiates the laser light on the object while moving the light-gathering spot along one of the lines to form the first modification region along the X direction as the circumferential direction of the one line, and performs the X-direction processing across the plurality of lines while changing the one line to the first Y direction to form the plurality of first modification regions arranged along the Y-direction as the diameter direction of the line within the YZ plane. Claim 3 A laser processing apparatus according to claim 1, wherein a spiral-shaped line is set on the object when viewed from the Z direction, and the control unit irradiates the laser light on the object while moving the light-gathering spot along the line, thereby forming the first modification region along the X direction as the tangential direction of the line, and performs the X-direction processing from the beginning to the end of the line to form the first modification region, thereby forming a plurality of the first modification regions arranged along the Y-direction as the direction intersecting the tangential direction of the line within the YZ plane. Claim 4 A laser processing device according to any one of claims 1 to 3, wherein the object has, when viewed in the Z direction, a first region including the center of the object and a second region including the periphery edge portion of the object as a region outer than the first region, and the control unit performs the first processing on the first region. Claim 5 A laser processing device according to any one of claims 1 to 3, wherein the object has, when viewed in the Z direction, a first region including the center of the object and a second region including the periphery edge portion of the object as a region outer than the first region, and the control unit performs the first processing on the second region. Claim 6 In claim 5, the second region has a boundary with the first region, and the control unit performs a second processing process after the first processing process, wherein a plurality of second modification regions are formed as the modification regions, having a positional relationship intersecting a plurality of first modification regions arranged along the Y direction at the boundary, and in the second processing process, the control unit modulates the laser light by controlling the spatial light modulator so that a third modification region, which is the second modification region closest to the first modification region among the plurality of second modification regions, becomes elongated in the Z direction, thereby imparting a first aberration to the laser light, wherein the third modification region is the second modification region furthest from the incident plane among the plurality of second modification regions, and the first aberration is such that when the aberration occurring in the direction of the optical axis of the laser light at the focusing position due to focusing the laser light on the object by the focusing unit is taken as the reference aberration, the first aberration is in the Z direction relative to the focusing spot of the laser light to which the reference aberration is imparted. A laser processing device having a water aberration for forming the above-mentioned concentrated spot in the shape of a long rod. Claim 7 A laser processing apparatus according to claim 6, wherein the boundary includes an inclined portion inclined with respect to the Z direction within a YZ plane including the Z direction and the Y direction, and the control unit modulates the laser light by controlling the spatial light modulator such that, when forming the modification region in the inclined portion, the beam shape at the focusing spot of the laser light within the YZ plane is inclined in the inclined direction of the inclined portion at least on the incident plane side rather than the center of the focusing spot. Claim 8 A laser processing device according to any one of claims 1 to 7, wherein in the first processing step, the control unit branches the laser light so that a plurality of light-gathering spots are formed within the virtual plane, wherein at least the positions in the Y direction are different from each other. Claim 9 A laser processing device according to claim 8, wherein in the first processing step, the control unit branches the laser light to form a plurality of light-gathering spots in which the positions in the X direction are additionally different within the virtual plane. Claim 10 A laser processing method for forming a modified region along a virtual plane inside an object along the incident plane of the laser light of the object by irradiating the object with laser light, comprising a processing process for forming the modified region by irradiating the laser light of the object while moving the laser light spot along the virtual plane, wherein in the processing process, within the virtual plane, a first processing is performed to form a plurality of the first modified regions arranged along the Y direction within a YZ plane including the X direction and the Y direction, by performing X-direction processing to form a first modified region as the modified region by irradiating the object with the laser light while moving the laser light spot along the X direction along the virtual plane, and changing the position of the laser light spot in the Y direction that follows the virtual plane and intersects the X direction to a first Y direction that extends from one side of the Y direction to the other. In the first processing, the laser light within the YZ plane A laser processing method in which the beam shape in the spot is inclined in the first Y direction on the incident plane side, at least more than the center of the concentrated spot.

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