Laser processing apparatus and laser processing method

Abstract

A laser processing apparatus for forming a modified region by irradiating a laser to an object, comprising: a support portion for supporting the object; an irradiation portion for irradiating the laser toward the object supported by the support portion; a movement portion for relatively moving a condensing region of the laser with respect to the object; and a control portion for controlling the movement portion and the irradiation portion. The object has a crystal structure including a (100) plane, one (110) plane, another (110) plane, a first crystal orientation orthogonal to the one (110) plane, and a second crystal orientation orthogonal to the another (110) plane, and the object is supported on the support portion with the (100) plane as an incident plane of the laser.

Description

Technical Field

[0001] One aspect of this disclosure relates to laser processing apparatus and laser processing methods. Background Technology

[0002] Patent Document 1 describes a laser processing apparatus comprising: a holding mechanism for holding a workpiece and a laser irradiation mechanism for irradiating the workpiece held by the holding mechanism with a laser. In the laser processing apparatus described in Patent Document 1, the laser irradiation mechanism, which has a focusing lens, is fixed relative to a base, and the holding mechanism is used to move the workpiece in a direction perpendicular to the optical axis of the focusing lens.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 5456510

[0006] Patent Document 2: Japanese Patent Application Publication No. 2020-069530 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in manufacturing processes such as semiconductor devices, there are cases where finishing processes are performed to remove the outer edge portion of a semiconductor wafer as an unwanted part. However, in order to remove this outer edge portion from the object, there is a concern that when a laser focus point is relatively moved along a line extending in a loop inside the outer edge of the object to form a modified region, the quality of the finished surface of the object formed by removing the outer edge portion is degraded due to the location of the process.

[0009] On the other hand, according to the inventors' understanding, during finishing processes, when a crack extends from the modified region to the opposite side of the surface from the laser incident surface of the object, it is required that the crack extend obliquely in the thickness direction rather than vertically along the thickness direction of the object. This is because, for example, when the crack extends along the thickness direction, it is necessary to prevent it from reaching other objects (e.g., other wafers attached to the wafer that is the object) disposed directly below the object along the thickness direction. That is, the inventors have a new understanding of the above-mentioned technical field, namely, the ability to suppress the quality degradation of the finished surface of the object whose outer edge portion has been removed, and the formation of oblique cracks.

[0010] Therefore, one aspect of this disclosure is to provide a laser processing apparatus and laser processing method that can suppress the quality reduction of the trimmed surface of an object whose outer edge portion has been removed and prevent the formation of oblique cracks.

[0011] Technical means to solve the problem

[0012] The inventors conducted in-depth research to solve the above-mentioned problems and obtained the following insights. First, regarding the object, which is a wafer with a (100) surface as the main surface and having a first crystal orientation orthogonal to one (110) surface and a second crystal orientation orthogonal to another (110) surface, the beam shape is formed with an angle greater than that between the first and second crystal orientations and the processing direction (the direction of relative movement of the focusing point), thereby suppressing the reduction in the quality of the outer surface (for example, see Patent Document 2 mentioned above).

[0013] More specifically, when the crack extending from the modified region is pulled by, for example, the first crystal orientation, the beam shape becomes elongated, and the orientation of its long side is not the same as the machining direction, but rather tilted relative to the machining direction to a second crystal orientation that is close to the opposite side of the first crystal orientation. Therefore, it is believed that by making the beam shape elongated to counteract the crack extension force caused by the crystal orientation (crystallization axis), the crack extends with high precision along the machining direction.

[0014] Furthermore, when cracks extending from the modified region are drawn by, for example, the second crystallization orientation, the beam shape becomes elongated, and the orientation of its long side is not the same as the machining travel direction, but rather inclined relative to the machining travel direction to the first crystallization orientation, which is opposite to the second crystallization orientation. Therefore, it is believed that by shaping the beam into an elongated form, the crack extension force caused by the crystallization orientation can be counteracted, allowing the cracks to extend with high precision along the machining travel direction BD. These results are believed to suppress the degradation of the finished surface quality.

[0015] On the other hand, based on the above insights, the inventors conducted further research and discovered that even when the orientation of the long side of the beam shape is set as described above based on the processing direction and the crystal structure, the relationship between the orientation of the long side of the beam shape and the tilt direction of the oblique crack allows for further suppression of the quality reduction of the finished surface. That is, when the orientation of the long side of the beam shape and the tilt direction of the oblique crack are on the same side relative to the processing direction, the quality of the finished surface is relatively good; conversely, when the orientation of the long side of the beam shape and the tilt direction of the oblique crack are on opposite sides relative to the processing direction, the quality of the finished surface is relatively poor.

[0016] In particular, when the point where the line specifying the processing direction intersects the second crystal orientation is set to 0°, the point where the line intersects the first crystal orientation is set to 90°, and the point midway between 0° and 90° is set to 45°, during processing at the 45° point, when the orientation of the long side of the beam shape and the tilt direction of the oblique crack are opposite to each other relative to the processing direction, a decrease in the quality of the finished surface is likely to occur. One aspect of this disclosure is based on the above-described insights.

[0017] That is, one aspect of the laser processing apparatus disclosed herein is a laser processing apparatus for irradiating an object with a laser to form a modified region, comprising: a support for supporting the object; an irradiation unit for irradiating the object supported by the support for irradiating with a laser; a moving unit for moving a focusing area of ​​the laser relative to the object; and a control unit for controlling the moving unit and the irradiation unit. The object has a crystalline structure comprising: a (100) facet, a (110) facet, another (110) facet, a first crystalline orientation orthogonal to one (110) facet, and a crystalline orientation orthogonal to the other (110) facet. The second crystallization orientation, and the object is supported on the support with the (100) surface becoming the incident surface of the laser. On the object, an annular line is provided, which, when viewed from the Z direction intersecting the incident surface, includes a first arc-shaped region and a second arc-shaped region having a boundary with the first region. The irradiation unit has a forming section that forms the laser with the focusing area having a long side direction when viewed from the Z direction. The control unit performs a first processing step, which, by controlling the irradiation unit and the moving section, moves the focusing area relative to the first region along the line, thereby forming a modified region on the object along the first region, and from the modified region... The modified region faces the opposite side of the incident surface of the object, forming an oblique crack extending obliquely relative to the Z direction; and the second processing involves controlling the irradiation unit and the moving unit to move the focusing region relative to the second region in the line, thereby forming a modified region on the object along the second region, and forming an oblique crack extending obliquely from the modified region toward the opposite side. In the first and second processing, the control unit controls the forming unit to shape the laser so that the long side direction of the focusing region is close to the processing travel direction that is the moving direction of the focusing region in the first and second crystallization orientations. The orientation of the side with the larger angle is tilted relative to the processing direction. By controlling the moving part, the clockwise and counterclockwise processing directions are made the same in the first and second processing processes. When the point where the second crystal orientation is orthogonal to the line is set to 0°, the point where the first crystal orientation is orthogonal to the line is set to 90°, and the point between 0° and 90° of the line is set to 45°, the boundary of the first and second regions is set in such a way that, when viewed from the Z direction in the first and second regions, the orientation of the tilt in the long side direction is 45° relative to the processing direction and the side extending from the oblique crack, which is on the same side.

[0018] Alternatively, one aspect of the laser processing method disclosed herein is a laser processing method for irradiating an object with a laser to form a modified region, comprising: a first processing step in which a focusing region of a laser is moved relative to a first region along a line set in the object, thereby forming a modified region in the object along the first region, and forming an oblique crack extending obliquely in a Z direction relative to the incident surface of the laser on the object from the modified region toward an opposite surface. The second processing step in which a focusing region is moved relative to a second region along a line, thereby forming a modified region in the object along the second region, and forming an oblique crack extending obliquely from the modified region toward the opposite surface. The object has a crystalline structure comprising: a (100) surface, a (110) surface, another (110) surface, a first crystal orientation orthogonal to one (110) surface, and a second crystal orientation orthogonal to the other (110) surface, and the (100) surface is set as the incident surface. When viewed from the Z direction, there is an annular line comprising a first arc-shaped region and a second arc-shaped region having a boundary with the first region. In the first and second processing steps, the laser is formed such that, when viewed from the Z direction, the focusing region has a long side direction, and the long side direction of the focusing region is inclined relative to the processing direction with the larger angle between the first and second crystal orientations and the processing direction which is the moving direction of the focusing region. In the first and second processing steps, the clockwise and counterclockwise processing directions are made the same. When the point where the second crystal orientation is orthogonal to the line is set to 0°, the point where the first crystal orientation is orthogonal to the line is set to 90°, and the point between 0° and 90° of the line is set to 45°, the boundary of the first and second regions is set such that, when viewed from the Z direction, the inclined direction of the long side direction in the first and second regions is 45° relative to the processing direction and the side extending from the oblique crack.

[0019] In these apparatuses and methods, the object has a crystalline structure comprising: a (100) facet, a (110) facet, another (110) facet, a first crystalline orientation orthogonal to one (110) facet, and a second crystalline orientation orthogonal to the other (110) facet. Furthermore, in both cases where a modified region is formed on the object along a line that relatively moves the laser focusing area (first processing, first processing step) and a modified region is formed on the object along a second region of that line (second processing, second processing step), the long side direction of the focusing area is inclined relative to the processing direction with an orientation closer to the larger angle between the first and second crystalline orientations and the processing direction. Therefore, as described above, the reduction in the quality of the trimmed surface can be suppressed.

[0020] On the other hand, in these apparatuses and methods, during the first and second processing steps (and the same applies to the first and second processing steps hereinafter the same), oblique cracks are formed on the opposite side of the modified region toward the object, extending at an angle relative to the Z direction (the direction intersecting the incident surface). Therefore, as explained above, the relationship between the extension direction of these oblique cracks and the orientation of the long side of the focusing region must be considered. In particular, when processing at a 45° point, when the orientation of the long side of the focusing region and the tilt direction of the oblique cracks are opposite to each other relative to the processing direction, a decrease in the quality of the finished surface is likely to occur.

[0021] To address this, in these apparatuses and methods, the boundary between the first and second regions is set such that the inclined direction of the long side of the first and second regions is aligned with the processing direction and the side where the oblique crack extends, both containing a 45° point. In other words, in the first and second regions, the areas processed with the long side of the focusing area and the inclined direction of the oblique crack being opposite to each other with respect to the processing direction will not reach the 45° point of the line. Therefore, quality degradation can be suppressed. Thus, according to these apparatuses and methods, quality degradation of the finished surface of the object can be suppressed, and oblique cracks can be prevented from forming.

[0022] Furthermore, in these apparatuses and methods, the direction of processing travel is the same in both the first and second processing steps. Therefore, compared to the case where the direction of processing travel is switched between the first and second processing steps, the time required for acceleration and deceleration of the relative movement of the laser focusing area can be reduced.

[0023] In one aspect of the laser processing apparatus disclosed herein, one of the first and second regions may be set to be longer than the other of the first and second regions. This allows the lengths of the first and second regions to be set differently.

[0024] In one aspect of the laser processing apparatus disclosed herein, the object may include: a first part and a second part arranged sequentially from opposite sides along the Z-direction; a control unit; for the first part, the forward and reverse directions of the processing travel direction are set to be the same, and a first processing process and a second processing process are performed; and for the second part, other processing processes different from the first and second processing processes are performed; in the other processing processes, the control unit, the irradiation control unit, and the movement unit are configured to make the forward and reverse directions of the processing travel direction the same throughout the entire line, and to move the focusing area relative to each other along the line, thereby forming a modified region and cracks extending from the modified region along the Z-direction on the object along the line. In this case, in the second part where cracks are formed along the Z-direction, laser processing is performed by making the orientation of the processing travel direction the same throughout the entire line. Therefore, compared to the case where the forward and reverse directions of the processing travel direction are switched in the first and second regions along the line in the second part, the time required for acceleration and deceleration of the relative movement of the laser focusing area can be reduced.

[0025] In one aspect of the laser processing apparatus disclosed herein, in other processing steps, the control unit controls the forming unit to form the laser so that the long side direction of the focusing region is along the processing travel direction. In this case, when forming the second part with cracks along the Z direction, it is not necessary to perform laser forming in a manner that changes the relationship between the long side direction of the focusing region and the processing travel direction between processing the first region and processing the second region in the line, thus simplifying the processing of the control unit.

[0026] In one aspect of the laser processing apparatus disclosed herein, the object may include a joining region that joins with other components. In the first and second processing steps, a control unit is formed with an oblique crack that slopes from the inner side of the joining region toward the outer edge of the joining region as it moves from the incident surface toward the opposite surface. In this case, when a portion of the object is removed from the object along the oblique crack, leaving a residual portion of the object, it is possible to prevent the object from extending outward across the joining region with other components.

[0027] In one aspect of the laser processing apparatus disclosed herein, the control unit may perform the following in the first and second processing steps: a first forming process in which the position of the focusing region in the Z direction is set to a first Z position, and the focusing region is moved relative to the object along a line, thereby forming a first modified region as a modified region and cracks extending from the first modified region on the object; and a second forming process in which the position of the focusing region in the Z direction is set to a second Z position that is closer to the incident surface than the first Z position, and the focusing region is moved relative to the object along a line, thereby forming a second modified region as a modified region and cracks extending from the first modified region. The crack extending from the second modified region is formed as follows: In the first forming process, the control unit sets the position of the focusing area in the Y direction, which intersects the processing travel direction and the Z direction, as the first Y position. In the second forming process, the control unit sets the position of the focusing area in the Y direction to a second Y position, which is shifted from the first Y position. Through the control of the forming unit, the laser is formed such that the shape of the focusing area within the YZ plane, which includes both the Y and Z directions, becomes an inclined shape that is at least tilted towards the shift direction closer to the incident surface than the center of the focusing area. This forms an oblique crack in the YZ plane, tilted towards the shift direction. Thus, an oblique crack tilted relative to the Z direction can be appropriately formed.

[0028] In one aspect of the laser processing apparatus disclosed herein, the forming unit may include a spatial light modulator for forming the laser by modulating the laser according to a modulation pattern, the irradiation unit includes a focusing lens for focusing the laser from the spatial light modulator toward an object, a second forming process, and a control unit that modulates the laser to an inclined shape by controlling the modulation pattern displayed on the spatial light modulator, thereby forming the laser. In this case, the spatial light modulator can be used to easily form the laser.

[0029] In one aspect of the laser processing apparatus disclosed herein, the modulation pattern may include: a coma pattern for imparting coma aberration to the laser; in a second forming process, a control unit controls the magnitude of the coma aberration in the coma pattern, thereby performing a first pattern control to make the shape of the focusing region tilted. According to the inventors' understanding, in this case, the shape of the focusing region in the YZ plane is arc-shaped. That is, in this case, the shape of the focusing region is tilted in a lateral displacement direction closer to the incident surface than the center of the focusing region, and tilted in a direction opposite to the displacement direction further away from the incident surface than the center of the focusing region. Even in this case, oblique cracks tilting in the displacement direction may be formed.

[0030] In one aspect of the laser processing apparatus disclosed herein, the modulation pattern may include a spherical aberration correction pattern for correcting spherical aberration of the laser. In the second forming process, the control unit shifts the center of the spherical aberration correction pattern in the Y direction relative to the center of the entrance pupil plane of the condenser lens, thereby performing a second pattern control to make the shape of the focusing region tilted. According to the inventors' understanding, in this case, similarly to the case using a coma aberration pattern, the shape of the focusing region in the YZ plane can be formed into an arc shape, and oblique cracks tilting in the displacement direction can be formed.

[0031] In one aspect of the laser processing apparatus disclosed herein, during the second forming process, the control unit displays a modulation pattern that is asymmetrical with respect to the axis along the processing direction on a spatial light modulator, thereby performing a third pattern control to make the shape of the focusing region tilted. According to the inventors' understanding, in this case, the overall shape of the focusing region in the YZ plane can be tilted in the displacement direction. In this case, oblique cracks tilting in the offset direction can also be formed.

[0032] In one aspect of the laser processing apparatus of this disclosure, the modulation pattern may include an elliptical pattern for shaping the focusing region in the Y direction and the XY plane (including the X and Y directions intersecting the Z direction) into an elliptical shape with the X direction as its longer side. In the second forming process, the control unit displays the modulation pattern on a spatial light modulator in a manner where the intensity of the elliptical pattern is asymmetrical relative to the axis along the X direction, thereby performing a fourth pattern control to make the shape of the focusing region tilted. According to the inventors, in this case, the shape of the focusing region in the YZ plane may also be formed as an arc, and oblique cracks tilting towards the displacement direction may be formed.

[0033] In one aspect of the laser processing apparatus of this disclosure, during the second forming process, the control unit displays a modulation pattern for forming a plurality of laser focusing points arranged along the shift direction in the YZ plane on a spatial light modulator, thereby performing a fifth pattern control to make the shape of the focusing region containing the plurality of focusing points into an inclined shape. According to the inventors' understanding, in this case, oblique cracks inclined in the shift direction can also be formed.

[0034] The effects of the invention

[0035] According to one aspect of this disclosure, a laser processing apparatus and a laser processing method may be provided, which suppress the degradation of the quality of the finished surface of the object whose outer edge portion has been removed, and prevent the formation of oblique cracks. Attached Figure Description

[0036] Figure 1This is a schematic diagram showing the structure of a laser processing apparatus according to one embodiment.

[0037] Figure 2 This is a schematic diagram showing the structure of the laser irradiation section.

[0038] Figure 3 It means Figure 2 The diagram shows the 4f lens unit.

[0039] Figure 4 It means Figure 2 The diagram shows a spatial light modulator.

[0040] Figure 5 It is a cross-sectional view of an object used to illustrate the concept of oblique crack formation.

[0041] Figure 6 It is a cross-sectional view of an object used to illustrate the concept of oblique crack formation.

[0042] Figure 7 It is a diagram showing the beam shape of the laser beam in the focusing area.

[0043] Figure 8 It is a graph representing the offset of the modulation pattern.

[0044] Figure 9 It is a cross-sectional photograph showing the formation state of oblique cracks.

[0045] Figure 10 It is a schematic top view of the object.

[0046] Figure 11 It is a cross-sectional photograph showing the formation state of oblique cracks.

[0047] Figure 12 It is a cross-sectional photograph showing the formation state of oblique cracks.

[0048] Figure 13 This is a diagram representing an example of a modulation pattern.

[0049] Figure 14 It is a diagram showing the intensity distribution at the entrance pupil of a condenser lens and the beam shape in the focusing area.

[0050] Figure 15 It is a graph showing the observation results of the beam shape and intensity distribution in the focusing area.

[0051] Figure 16 This is a diagram representing an example of a modulation pattern.

[0052] Figure 17 This is a diagram illustrating other examples of asymmetric modulation patterns.

[0053] Figure 18 It is a diagram showing the intensity distribution at the entrance pupil of a condenser lens and the beam shape in the focusing area.

[0054] Figure 19 This is an example of a modulation pattern and a diagram showing the formation of a focusing area.

[0055] Figure 20 It is a diagram representing the object being processed.

[0056] Figure 21 It is a diagram representing the object being processed.

[0057] Figure 22 This is a schematic diagram showing the shape of the beam in the focusing area.

[0058] Figure 23 This is a schematic diagram showing the shape of the beam in the focusing area.

[0059] Figure 24 This is a diagram representing a finishing or processing step.

[0060] Figure 25 This is a diagram representing a finishing or processing step.

[0061] Figure 26 This is a diagram representing a finishing or processing step.

[0062] Figure 27 This is a diagram representing a finishing or processing step.

[0063] Figure 28 This is a diagram representing a finishing or processing step.

[0064] Figure 29 This is a diagram representing a finishing or processing step.

[0065] Figure 30 This is a diagram showing an object processed by laser according to one embodiment.

[0066] Figure 31 yes Figure 30 The cross-sectional view of the object shown.

[0067] Figure 32 yes Figure 30 The top view of the object shown.

[0068] Figure 33 It is a cross-sectional photograph showing the processing result.

[0069] Figure 34 It is a cross-sectional photograph showing the processing result.

[0070] Figure 35 This is a schematic diagram used to illustrate the processing test.

[0071] Figure 36 This is a schematic diagram illustrating the relationship between the processing direction, beam shape, and oblique cracking in a processing test.

[0072] Figure 37 It means Figure 35 , 36 The table shows the results of the processing tests.

[0073] Figure 38 This is a table that represents the results of processing tests.

[0074] Figure 39 It is a cross-sectional photograph showing the results of the processing test.

[0075] Figure 40 This is a diagram illustrating a step in laser processing according to one embodiment.

[0076] Figure 41 This is a diagram illustrating a step in laser processing according to one embodiment.

[0077] Figure 42 This is a diagram illustrating a step in laser processing according to one embodiment.

[0078] Figure 43 This is a diagram illustrating a step in laser processing according to one embodiment.

[0079] Figure 44 This is a diagram illustrating a step in laser processing according to one embodiment.

[0080] Figure 45 This is a diagram illustrating a step in laser processing according to one embodiment.

[0081] Figure 46 This is a diagram illustrating a step in laser processing according to one embodiment.

[0082] Figure 47 This is a diagram illustrating a step in laser processing according to one embodiment.

[0083] Figure 48 This is a diagram showing an object processed by laser according to one embodiment.

[0084] Figure 49 This is a table that represents the results of processing tests.

[0085] Figure 50 This is a table that represents the results of processing tests. Detailed Implementation

[0086] Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. Furthermore, in the various figures, the same or equivalent parts are sometimes given the same symbols, and repeated descriptions are omitted. Additionally, in the various figures, a rectangular coordinate system defined by the X-axis, Y-axis, and Z-axis is sometimes shown.

[0087] [Laser processing equipment and an overview of laser processing]

[0088] Figure 1 This is a schematic diagram illustrating the structure of a laser processing apparatus according to one embodiment. For example... Figure 1 As shown, the laser processing apparatus 1 includes: a stage (support) 2, an irradiation unit 3, moving units 4 and 5, and a control unit 6. The laser processing apparatus 1 is used to form a modified region 12 on a workpiece 11 by irradiating the workpiece 11 with a laser L.

[0089] The stage 2, for example, holds the film adhered to the object 11, thereby supporting the object 11. The stage 2 can rotate with an axis parallel to the Z direction as its rotation axis. The stage 2 can also move along the X and Y directions respectively. Furthermore, the X and Y directions are first and second horizontal directions that intersect (orthogonal) each other, and the Z direction is the vertical direction.

[0090] The irradiation unit 3 focuses a transmissive laser L onto the object 11. If the laser L is focused inside the object 11 supported by the stage 2, the laser L is specifically absorbed in the area corresponding to the focusing region C (e.g., the center Ca described later), forming a modified region 12 inside the object 11. Furthermore, the focusing region C, which will be described in detail later, is the area defined as either the position where the laser beam intensity is highest or a range from the center of beam intensity.

[0091] The modified region 12 is a region whose density, refractive index, mechanical strength, and other physical properties differ from the surrounding unmodified region. Examples of modified regions 12 include: melt-treated regions, cracked regions, insulation failure regions, and regions with refractive index changes. The modified region 12 is formed such that cracks extend from the modified region 12 to the incident side of the laser L and to the opposite side. This modified region 12 and the cracks are used, for example, for cutting the object 11.

[0092] As an example, if the stage 2 is moved along the X direction and the focusing region C is moved relative to the object 11 along the X direction, multiple modification points 12s are formed in a row along the X direction. A modification point 12s is formed by irradiation with a single pulse of laser L. A row of modification regions 12 is a collection of multiple modification points 12s arranged in a row. Adjacent modification points 12s may be connected or separated depending on the relative movement speed of the focusing region C relative to the object 11 and the repetition frequency of the laser L.

[0093] The moving part 4 includes: a first moving part 41 that moves the stage 2 along one direction in a plane intersecting (or orthogonal) to the Z direction; and a second moving part 42 that moves the stage 2 along other directions in a plane intersecting (or orthogonal) to the Z direction. For example, the first moving part 41 moves the stage 2 along the X direction, and the second moving part 42 moves the stage 2 along the Y direction. Additionally, the moving part 4 rotates the stage 2 about an axis parallel to the Z direction. The moving part 5 supports the irradiation part 3. The moving part 5 moves the irradiation part 3 along the X, Y, and Z directions. With the laser L focusing area C formed, the stage 2 and / or the irradiation part 3 are moved, thereby causing the focusing area C to move relative to the object 11. That is, the moving parts 4 and 5 are moving parts that move at least one of the stage 2 and the irradiation part 3 in a manner that causes the focusing area C of the laser L to move relative to the object 11.

[0094] The control unit 6 controls the operation of the stage 2, the irradiation unit 3, and the moving units 4 and 5. The control unit 6 includes a processing unit, a storage unit, and an input receiving unit (not shown). The processing unit is configured as a computer device including a processor, memory, storage unit, and communication device. In the processing unit, the processor executes software (programs) loaded into memory, etc., and controls the reading and writing of data in the memory and storage unit, as well as communication via the communication device. The storage unit, such as a hard disk, stores various types of data. The input receiving unit is an interface unit that displays various information and receives various types of input from the user. The input receiving unit constitutes a GUI (Graphical User Interface).

[0095] Figure 2 It means Figure 1 A schematic diagram of the structure of the irradiation unit is shown. Figure 2 In the diagram, a virtual line A is shown, representing the predetermined laser processing. (Example) Figure 2As shown, the irradiation unit 3 includes: a light source 31, a spatial light modulator (shaping unit) 7, a condenser lens 33, and a 4f lens unit 34. The light source 31 outputs laser light L, for example, via pulse oscillation. Alternatively, the irradiation unit 3 may not have a light source 31, but instead be configured to introduce laser light L from outside the irradiation unit 3. The spatial light modulator 7 modulates the laser light L output from the light source 31. The condenser lens 33 focuses the laser light L modulated by the spatial light modulator 7 and output from the spatial light modulator 7 toward the object 11.

[0096] like Figure 3 As shown, the 4f lens unit 34 has a pair of lenses 34A and 34B arranged in the optical path of the laser L from the spatial light modulator 7 toward the condenser lens 33. The pair of lenses 34A and 34B constitute a telecentric optical system on both sides of the modulation surface 7a of the spatial light modulator 7 and the entrance pupil surface 33a of the condenser lens 33, which are in an imaging relationship. Thus, the image of the laser L at the modulation surface 7a of the spatial light modulator 7 (the image of the laser L modulated by the spatial light modulator 7) is imaged onto the entrance pupil surface 33a of the condenser lens 33. Furthermore, Fs in the figure represents the Fourier surface.

[0097] like Figure 4 As shown, the spatial light modulator 7 is a spatial light modulator (SLM) of reflective liquid crystal on silicon (LCOS). The spatial light modulator 7 is constructed by sequentially stacking a driving circuit layer 72, a pixel electrode layer 73, a reflective film 74, an alignment film 75, a liquid crystal layer 76, an alignment film 77, a transparent conductive film 78, and a transparent substrate 79 on a semiconductor substrate 71.

[0098] The semiconductor substrate 71 is, for example, a silicon substrate. The driving circuit layer 72 forms an active matrix circuit on the semiconductor substrate 71. The pixel electrode layer 73 includes a plurality of pixel electrodes 73a arranged in a matrix along the surface of the semiconductor substrate 71. Each pixel electrode 73a is formed, for example, of a metal material such as aluminum. A voltage is applied to each pixel electrode 73a by the driving circuit layer 72.

[0099] The reflective film 74 is, for example, a dielectric multilayer film. An alignment film 75 is disposed on the surface of the liquid crystal layer 76 on the side of the reflective film 74, and an alignment film 77 is disposed on the surface of the liquid crystal layer 76 opposite to the reflective film 74. Each alignment film 75 and 77 is formed, for example, from a polymer material such as polyimide, and a rubbing treatment is performed, for example, on the contact surface between each alignment film 75 and 77 and the liquid crystal layer 76. The alignment films 75 and 77 align the liquid crystal molecules 76a contained in the liquid crystal layer 76 in a certain direction.

[0100] A transparent conductive film 78 is disposed on the surface of the transparent substrate 79 on the side of the alignment film 77, facing the pixel electrode layer 73 through the liquid crystal layer 76, etc. The transparent substrate 79 is, for example, a glass substrate. The transparent conductive film 78 is formed of, for example, a light-transmitting and conductive material such as ITO. The transparent substrate 79 and the transparent conductive film 78 allow the laser L to pass through.

[0101] In the spatial light modulator 7 configured as described above, if a signal representing a modulation pattern is input from the control unit 6 to the drive circuit layer 72, a voltage corresponding to that signal is applied to each pixel electrode 73a, forming an electric field between each pixel electrode 73a and the transparent conductive film 78. When this electric field is formed, the alignment direction of the liquid crystal molecules 76a in each region corresponding to each pixel electrode 73a changes, and the refractive index in each region corresponding to each pixel electrode 73a changes. This state is characterized by a modulation pattern displayed on the liquid crystal layer 76. The modulation pattern is used to modulate the laser L.

[0102] That is, when the liquid crystal layer 76 displays a modulation pattern, if laser L is incident on the liquid crystal layer 76 from the outside via the transparent substrate 79 and the transparent conductive film 78, reflected by the reflective film 74, and exits from the liquid crystal layer 76 through the transparent conductive film 78 and the transparent substrate 79 to the outside, then laser L is modulated according to the modulation pattern displayed on the liquid crystal layer 76. Thus, according to the spatial light modulator 7, laser L can be modulated (e.g., modulation of the intensity, amplitude, phase, polarization, etc. of laser L) by appropriately setting the modulation pattern displayed on the liquid crystal layer 76. Furthermore, Figure 3 The modulation surface 7a shown is, for example, a liquid crystal layer 76.

[0103] As described above, the laser L output from the light source 31 is incident on the condenser lens 33 via the spatial light modulator 7 and the 4f lens unit 34. The condenser lens 33 focuses the light onto the object 11, thereby forming a modified region 12 and cracks extending from the modified region 12 on the object 11 within the focused region C. Furthermore, the control unit 6 controls the moving units 4 and 5 to move the focused region C relative to the object 11, thereby forming the modified region 12 and cracks along the moving direction of the focused region C.

[0104] [Explanation of insights regarding the formation of oblique cracks]

[0105] Here, the direction of relative movement (processing travel direction) of the focusing area C at this time is defined as the X direction. Furthermore, the direction intersecting (or orthogonal) with the incident surface of the laser L of the object 11, i.e., the first surface 11a, is defined as the Z direction. Additionally, the direction intersecting (or orthogonal) with both the X and Z directions is defined as the Y direction. The X and Y directions are along the first surface 11a. Furthermore, the Z direction can also be defined as the optical axis of the focusing lens 33, the optical axis of the laser L focused towards the object 11 via the focusing lens 33.

[0106] like Figure 5 As shown, the requirement is that, within the intersecting surface (including the YZ surface S encompassing the Y and Z directions) that intersects the processing direction (i.e., the X direction), a crack is formed obliquely along a line RA (here, a line RA inclined at a predetermined angle θ from the Y direction) that is inclined relative to the Z and Y directions. Based on the inventor's understanding of the formation of such oblique cracks, a processing example will be shown for explanation.

[0107] Here, modified regions 12a and 12b are formed as modified regions 12. Consequently, the crack 13a extending from modified region 12a and the crack 13b extending from modified region 12b are connected, forming a crack 13 extending obliquely along line RA. Here, firstly, as... Figure 6 As shown, a focusing region C1 is formed by setting the first surface 11a of the object 11 as the incident surface of the laser L. On the other hand, a focusing region C2 is formed by setting the first surface 11a as the incident surface of the laser L on a side further from the focusing region C1. At this time, the focusing region C2 is shifted by a distance Sz in the Z direction compared to the focusing region C1, and by a distance Sy in the Y direction compared to the focusing region C1. The distances Sz and Sy, as examples, correspond to the inclination of the line RA.

[0108] On the other hand, such as Figure 7 As shown, a spatial light modulator 7 is used to modulate the laser L, thereby making the beam shape within the YZ plane S of the focusing region C (at least the focusing region C2) an inclined shape that is tilted relative to the Z direction towards the shift direction (in this case, the negative side of the Y direction), at least on the side closer to the first plane 11a than the center Ca of the focusing region C. Figure 7 For example, it becomes: an arc shape that, on the side closer to the first surface 11a than the center Ca, is inclined to the negative side of the Y direction relative to the Z direction, and on the opposite side closer to the first surface 11a than the center Ca, it is also inclined to the negative side of the Y direction relative to the Z direction. Furthermore, the beam shape of the focusing region C within the YZ plane S refers to the intensity distribution of the laser L in the focusing region C within the YZ plane S.

[0109] As described above, at least two focusing regions C1 and C2 are shifted in the Y direction, and the beam shape of at least focusing region C2 (which in this case includes both focusing regions C1 and C2) becomes tilted, thereby achieving the desired effect. Figure 9As shown in (a), a slanted, extending crack 13 can be formed. Furthermore, for example, by controlling the modulation pattern of the spatial light modulator 7, it is also possible to simultaneously form focusing regions C1 and C2 and form modified region 12 and crack 13 by branching the laser L (multi-focus processing), or after forming modified region 12a and crack 13a by forming focusing region C1, modified region 12b and crack 13b can be formed by forming focusing region C2 (single-pass processing).

[0110] Alternatively, other focusing areas can be formed between focusing area C1 and focusing area C2, thereby achieving the desired effect. Figure 9 As shown in (b), there is another modified region 12c between modified region 12a and modified region 12b, forming a longer, inclined, extended crack 13.

[0111] Next, an explanation will be given regarding the understanding of how to make the beam shape within the YZ plane S of the focusing region C into an inclined shape. First, the definition of the focusing region C will be specifically explained. Here, the focusing region C is a region within a specified range from the center Ca (for example, a range of ±25 μm from the center Ca in the Z direction). The center Ca, as described above, is the position of the highest beam intensity or the centroid of the beam intensity. The centroid of the beam intensity is, for example, the position on the optical axis of the laser L where the beam intensity is located when there is no modulation by a modulation pattern that shifts the optical axis of the laser L, such as a modulation pattern used to branch the laser L. The position of the highest beam intensity or the centroid of the beam intensity can be obtained as follows. That is, the laser L is used to irradiate the object 11 with the output of the laser L reduced to a level that does not form the modified region 12 in the object 11 (lower than the processing threshold). Furthermore, the reflected light of the laser L from the surface opposite to the incident surface of the laser L of the object 11 (here, the second surface 11b) is, for example, directed to... Figure 15 Multiple positions F1 to F7 in the Z direction, as shown, were captured by a camera. Based on the obtained images, the position and center of gravity of the beam with the highest intensity can be determined. Furthermore, the modified region 12 is formed near this center Ca.

[0112] To make the beam shape in the focusing region C tilted, there is a method to offset the modulation pattern. More specifically, in the spatial light modulator 7, various patterns are displayed, including: a deformation correction pattern for correcting wavefront distortion, a grating pattern for laser branching, a split pattern, an astigmatic pattern, a coma aberration pattern, and a spherical aberration correction pattern (patterns overlapping these patterns are shown). Among them, such as Figure 8 As shown, the spherical aberration correction pattern Ps is shifted, thereby adjusting the beam shape of the focusing region C.

[0113] exist Figure 8 In the example, on the modulation surface 7a, the center Pc of the spherical aberration correction pattern Ps is offset by an amount Oy1 relative to the center Lc (beam point) of the laser L in the negative Y direction. As described above, the modulation surface 7a is imaged onto the entrance pupil surface 33a of the condenser lens 33 via the 4f lens unit 34. Therefore, the offset of the modulation surface 7a in the entrance pupil surface 33a becomes an offset in the positive Y direction. That is, in the entrance pupil surface 33a, the center Pc of the spherical aberration correction pattern Ps is offset by an amount Oy2 from the center Lc of the laser L and the center of the entrance pupil surface 33a (which coincides with the center Lc here) in the positive Y direction.

[0114] As described above, the spherical aberration correction pattern Ps is shifted, thereby changing the beam shape of the focusing region C of the laser L, as follows: Figure 7 As shown, it is deformed into an arc-shaped tilted shape. As described above, shifting the spherical aberration correction pattern Ps is equivalent to imparting coma to the laser L. Therefore, the beam shape of the focusing region C can also be tilted by including a coma aberration pattern for imparting coma to the laser L in the modulation pattern of the spatial light modulator 7. Furthermore, as the coma aberration pattern, a pattern equivalent to 9 terms of the Zernike polynomial (the Y component of the 3rd coma aberration) can be used, that is, a pattern in which coma occurs in the Y direction.

[0115] Next, I will explain my understanding of the relationship between the crystallinity of object 11 and the cracks 13. Figure 10 This is a schematic top view of the object. Here, object 11 is a silicon wafer (775μm, <100> 1Ω·cm), forming a notch 11d. For this object 11, the first machining example, where the machining travel direction, i.e., the X direction, aligns with the 0° (110) surface, is shown in... Figure 11 (a) illustrates the second machining operation where the X direction is matched with 15°. Figure 11 (b) illustrates other processing techniques that match 30°. Figure 12 (a) illustrates the fourth machining process that matches the 45° (100) surface. Figure 12 (b) In each processing example, the angle θ of the line RA in the YZ plane S from the Y direction is set to 71°.

[0116] Furthermore, in each processing example, a single-path processing is adopted. In the first path, the focusing region C1 is moved relatively in the X direction to form the modified region 12a and the crack 13a. Then, in the second path, the focusing region C2 is moved relatively in the X direction to form the modified region 12b and the crack 13b. The processing conditions for the first and second paths are described below. Additionally, CP below represents the intensity of the focusing correction, and coma (LBA offset Y) represents the amount of offset of the spherical aberration correction pattern Ps in the Y direction in pixel units of the spatial light modulator 7.

[0117] <Path 1>

[0118] Z-axis position: 161μm

[0119] CP: -18

[0120] Output: 2W

[0121] Speed: 530mm / s

[0122] Frequency: 80kHz

[0123] Comet (LBA offset Y): -5

[0124] Y-direction position: 0

[0125] <Path 2>

[0126] Z-axis position: 151μm

[0127] CP: -18

[0128] Output: 2W

[0129] Speed: 530mm / s

[0130] Frequency: 80kHz

[0131] Comet (LBA offset Y): -5

[0132] Y-axis position: 0.014mm

[0133] like Figure 11 and Figure 12 As shown, in any case, a crack 13 can be formed along a line RA that is inclined at 71° relative to the Y direction. That is, regardless of the main crack surfaces of the object 11, namely the (110) surface, (111) surface, and (100) surface, a crack 13 that extends obliquely can be formed along the desired line RA.

[0134] Furthermore, the control of the beam shape used to form this obliquely extending crack 13 is not limited to the examples described above. Next, other examples for making the beam shape oblique will be described. For example... Figure 13 As shown in (a), the laser L can also be modulated using a modulation pattern PG1 that is asymmetrical with respect to the axis Ax along the processing travel direction, i.e., the X direction, so that the beam shape of the focusing region C becomes tilted. The modulation pattern PG1 includes a grating pattern Ga on the negative side further in the Y direction than the axis Ax, and an unmodulated region Ba on the positive side further in the Y direction than the axis Ax. The axis Ax passes through the center Lc of the laser L beam point in the Y direction and extends along the X direction. In other words, the modulation pattern PG1 only includes the grating pattern Ga on the positive side further in the Y direction than the axis Ax. Furthermore, Figure 13 (b) will Figure 13 The modulation pattern PG1 of (a) is reversed in a manner corresponding to the entrance pupil 33a of the condenser lens 33.

[0135] Figure 14 (a) represents the intensity distribution of laser L at the entrance pupil surface 33a of the condenser lens 33. For example... Figure 14 As shown in (a), by using this modulation pattern PG1, the portion of the laser L incident on the spatial light modulator 7 that is modulated by the grating pattern Ga becomes non-incident at the entrance pupil surface 33a of the condenser lens 33. The result is as follows: Figure 14 (b) and Figure 15 As shown, the beam shape of the focusing region C within the YZ plane S can be made into an inclined shape that is tilted in one direction relative to the Z direction.

[0136] That is, in this case, the beam shape of the focusing region C is such that, on the side closer to the first surface 11a than the center Ca of the focusing region C, it is tilted to the negative side relative to the Z direction towards the Y direction, and on the opposite side closer to the first surface 11a than the center Ca of the focusing region C, it is tilted to the positive side relative to the Z direction towards the Y direction. Furthermore, Figure 15 Figures (b) show that: Figure 15 The intensity distribution of laser L at positions F1 to F7 in the Z direction shown in (a) is the result of actual observation by the camera. When the beam shape of the focusing area C is controlled in this way, similarly to the example above, a slanted, extending crack 13 can be formed.

[0137] Furthermore, as a modulation pattern that is asymmetrical with respect to the axis Ax, it can also be adopted. Figure 16The modulation patterns PG2, PG3, and PG4 are shown. Modulation pattern PG2, on the negative side further in the Y direction than the axis Ax, includes a non-modulation region Ba and a grating pattern Ga arranged sequentially in a direction away from the axis Ax, and on the positive side further in the Y direction than the axis Ax, it includes the non-modulation region Ba. That is, a portion of the region on the negative side of modulation pattern PG2, further in the Y direction than the axis Ax, includes the grating pattern Ga.

[0138] The modulation pattern PG3, on the negative side further in the Y direction than the axis Ax, includes an unmodulated region Ba and a grating pattern Ga arranged sequentially in a direction away from the axis Ax. On the positive side further in the Y direction than the axis Ax, it also includes an unmodulated region Ba and a grating pattern Ga arranged sequentially in a direction away from the axis Ax. In the modulation pattern PG3, the proportions of the unmodulated region Ba and the grating pattern Ga are different on the positive and negative sides (the unmodulated region Ba is relatively narrower on the negative side of the Y direction), thus making it asymmetrical relative to the axis Ax.

[0139] Similar to modulation pattern PG2, modulation pattern PG4 includes a grating pattern Ga in a region on the negative side of the Y direction, further away from the axis Ax. In modulation pattern PG4, the region containing the grating pattern Ga is further incorporated into the X direction. That is, in modulation pattern PG4, the region on the negative side of the Y direction, further away from the axis Ax, includes: a non-modulated region Ba, the grating pattern Ga, and another non-modulated region Ba arranged sequentially in the X direction. Here, the grating pattern Ga is disposed in the region containing the axis Ay along the Y direction, at the center Lc of the laser beam point passing through the X direction.

[0140] By using any of the modulation patterns PG2 to PG4 described above, the beam shape of the focusing region C can be made to be an inclined shape that is tilted at least on the side closer to the first surface 11a than the center Ca, in the negative direction of the Y direction relative to the Z direction. That is, in order to control the beam shape of the focusing region C to be tilted at least on the side closer to the first surface 11a than the center Ca, in the negative direction of the Y direction relative to the Z direction, as with modulation patterns PG1 to PG4, or not limited to modulation patterns PG1 to PG4, an asymmetric modulation pattern including a grating pattern Ga can be used.

[0141] Furthermore, the asymmetric modulation pattern used to make the beam shape of the focusing region C tilted is not limited to the use of the grating pattern Ga. Figure 17 These are diagrams illustrating other examples of asymmetric modulation patterns. For example... Figure 17 As shown in (a), the modulation pattern PE contains an elliptical pattern Ew on the negative side of the Y direction, which is closer to the axis Ax, and an elliptical pattern Es on the positive side of the Y direction, which is closer to the axis Ax. Furthermore, Figure 17 (b) will Figure 17The modulation pattern PE of (a) is reversed in a manner corresponding to the entrance pupil surface 33a of the condenser lens 33.

[0142] like Figure 17 As shown in (c), elliptical patterns Ew and Es are both used to shape the beam in the focusing region C of the XY plane, which includes both the X and Y directions, into an elliptical shape with the X direction as its longer side. However, the modulation intensity differs between elliptical patterns Ew and Es. More specifically, the modulation intensity achieved by elliptical pattern Es is greater than that achieved by elliptical pattern Ew. That is, the focusing region Cs formed by the laser L modulated by elliptical pattern Es has a longer elliptical shape in the X direction compared to the focusing region Cw formed by the laser L modulated by elliptical pattern Ew. Here, a relatively stronger elliptical pattern Es is positioned on the negative side in the Y direction, closer to the axis Ax.

[0143] like Figure 18 As shown in (a), by using this modulation pattern PE, the beam shape of the focusing region C within the YZ plane S can be made into an inclined shape that is tilted towards the negative Y direction relative to the Z direction on the side closer to the first surface 11a than the center Ca. In particular, in this case, the beam shape of the focusing region C within the YZ plane S can also be made such that it is also tilted towards the negative Y direction relative to the Z direction on the opposite side closer to the first surface 11a than the center Ca, forming an arc shape as a whole. Furthermore, Figure 18 Figures (b) show that: Figure 18 The intensity distribution of laser L in the XY plane at positions H1 to F8 in the Z direction shown in (a) is the actual observation result obtained by the camera.

[0144] Furthermore, the modulation pattern used to make the beam shape of the focusing region C tilted is not limited to the asymmetrical patterns described above. As an example, such modulation patterns can be listed as follows: Figure 19 As shown, a pattern is used to modulate laser L by forming focusing points CI at multiple locations within the YZ plane S, and by forming a focusing region C of an inclined shape from the entirety of the multiple focusing points CI (including the multiple focusing points CI). As an example of such a modulation pattern, it can be formed based on an axicon lens pattern. When using this modulation pattern, the modified region 12 itself can also be formed obliquely within the YZ plane S. Therefore, in this case, the oblique crack 13 can be correctly formed according to the desired tilt. On the other hand, when using this modulation pattern, there is a tendency for the length of the crack 13 to be shorter compared to the other examples described above. Therefore, by using various modulation patterns according to requirements, the desired processing can be performed.

[0145] Furthermore, the aforementioned focusing point CI is, for example, a point for focusing unmodulated laser light. As described above, according to the inventors' understanding, by shifting at least two modified regions 12a and 12b in the Y and Z directions within the YZ plane S, and by making the beam shape of the focusing region C in the YZ plane S oblique, a crack 13 extending obliquely in the Y direction relative to the Z direction can be formed.

[0146] Furthermore, when controlling the beam shape, high-energy processing can be achieved compared to using diffraction grating patterns to remove (cut) a portion of the laser when using spherical aberration correction patterns, coma aberration patterns, and elliptical patterns. Additionally, this is effective in cases where crack formation is a concern. Furthermore, when using coma aberration patterns in multifocal processing, the beam shape can be tilted only in a portion of the focusing area. Moreover, when using axial conical lens patterns, the use of other patterns is effective when the formation of modified regions is a concern, compared to other patterns.

[0147] [An example of finishing and processing]

[0148] Next, an example of trimming processing will be described. Trimming processing is the process of removing unwanted portions from the object 11. Trimming processing includes a laser processing method in which a focusing area is focused on the object 11 to irradiate it with laser L, thereby forming a modified region 12 on the object 11. The object 11 may include, for example, a semiconductor wafer formed in a circular plate shape. The object is not particularly limited and may be formed from various materials and may have various shapes. Functional elements (not shown) are formed on the second surface 11b of the object 11. Functional elements include, for example, light-receiving elements such as photodiodes, light-emitting elements such as laser diodes, and circuit elements such as memory.

[0149] Figure 20 and Figure 21 A diagram is a representation of the object being processed. For example... Figure 20 , 21 As shown, an effective region R and a removal region E are defined on the object 11. The effective region R corresponds to the portion of the acquired semiconductor element. Here, the effective region R is a circular plate-shaped portion including the central part when the object 11 is viewed from the thickness direction. The removal region E is the region of the object 11 that is further outward than the effective region R. The removal region E is the outer edge portion of the object 11 outside the effective region R. Here, the removal region E is a ring-shaped portion surrounding the effective region R. The removal region E includes the peripheral portion (the chamfered outer edge) when the object 11 is viewed from the thickness direction. The setting of the effective region R and the removal region E can be performed in the control unit 6. The effective region R and the removal region E can also be specified by coordinates.

[0150] The mounting stage 2 is a support on which the object 11 is placed. In this embodiment, the mounting stage 2 holds the object 11 with its first surface 11a as the laser incident surface (i.e., the upper side) and its second surface 11b as the mounting stage 2 side (i.e., the lower side). The mounting stage 2 has a rotation axis Cx located at its center. The rotation axis Cx is an axis extending along the Z direction. The mounting stage 2 is rotatable about the rotation axis Cx. The mounting stage 2 is driven to rotate by the driving force of a known drive device such as a motor.

[0151] The irradiation unit 3 irradiates the object 11 placed on the mounting stage 2 with laser L along the Z direction, forming a modified region inside the object 11. The irradiation unit 3 is mounted on the moving unit 5. The irradiation unit 3 can move linearly along the Z direction by the driving force of a known drive device such as a motor. The irradiation unit 3 can also move linearly in the X and Y directions by the driving force of a known drive device such as a motor.

[0152] The irradiation unit 3, as described above, includes a spatial light modulator 7. The spatial light modulator 7 forms a shaping unit that shapes the shape of a focusing region C (i.e., the shape of the focusing region C when viewed from the Z direction) within a plane perpendicular to the optical axis of the laser L (hereinafter also referred to as the "beam shape"). The spatial light modulator 7 shapes the laser L such that the beam shape when viewed from the Z direction has its long side in the direction of its long side. For example, the spatial light modulator 7 displays a modulation pattern that makes the beam shape elliptical, thereby shaping the beam shape into an elliptical shape.

[0153] The beam shape is not limited to an ellipse; any elongated shape is acceptable. The beam shape can also be a flat circle, an oblong shape, or a rectangle. The beam shape can also be an elongated triangle, rectangle, or polygon. The modulation pattern of this spatial light modulator 7, which realizes the beam shape, can also include at least one of a slit pattern and a diffused beam pattern. Furthermore, when the laser L has multiple focusing regions C due to diffused beams, the shape of the most upstream focusing region C in the optical path of the laser L is the beam shape of this embodiment (the same applies to other lasers). Here, the long side direction is the direction of the major axis of the elliptical beam shape, also referred to as the elliptical major axis direction.

[0154] The beam shape is not limited to the shape of the focal point; it can also be the shape near the focal point, as long as it is a part of the focal region C. For example, in the case of a laser L with astigmatism, such as... Figure 22 As shown in (a), in the region near the laser incident surface near the focal point, the beam shape has a long-side direction NH. Figure 22The beam intensity distribution in the plane of the beam shape of (a) (in the plane at the Z-direction position on the laser incident surface near the focal point) becomes a strong intensity distribution in the long side direction NH, and the direction of the strong beam intensity is consistent with the long side direction NH.

[0155] In the case of a laser L with astigmatism, such as Figure 22 As shown in (c), in the region opposite to the laser incident surface near the focal point, the beam shape has a long side direction NH (refer to) for the region on the laser incident surface side. Figure 22 (a) is perpendicular to the long side direction NH0. Figure 22 The beam intensity distribution within the plane of the beam shape of (c) (in the plane at the Z-direction position on the opposite side of the laser incident surface near the focal point) becomes a beam with a stronger intensity distribution in the long-side direction NH0, and the direction of the stronger beam intensity coincides with the long-side direction NH0. In the case of a laser L with astigmatism, such as Figure 22 As shown in (b), in the region between the laser incident surface and its opposite surface near the focal point, the focal region C becomes a circle without a long side direction.

[0156] In the case of a laser L with such astigmatism, the focusing region C, which is the object of this embodiment, includes the region on the laser incident surface side near the focusing point, and the beam shape, which is the object of this embodiment, is... Figure 22 The beam shape shown in (a).

[0157] Furthermore, by adjusting the modulation pattern of the spatial light modulator 7, the light-focusing region C can be arbitrarily controlled. Figure 22 The position of the beam shape shown in (a). For example, it can be controlled to be located in the region opposite to the laser incident surface near the focal point, having Figure 22 The beam shape shown in (a). Additionally, for example, it can be controlled to have, in the region between the laser incident surface side and its opposite surface near the focal point, a beam shape... Figure 22 The beam shape shown in (a). The location of a portion of the focusing region C is not particularly limited, as long as it is located anywhere between the laser incident surface of the object 11 and its opposite surface.

[0158] Additionally, for example, in the case of slit or elliptical optical systems resulting from the use of modulation pattern control and / or mechanical mechanisms, such as Figure 23 As shown in (a), in the region near the laser incident surface near the focal point, the beam shape has a long-side direction NH. Figure 23 The beam intensity distribution in the plane of the beam shape of (a) (in the plane at the Z-direction position on the laser incident surface near the focal point) becomes a strong intensity distribution in the long side direction NH, and the direction of the strong beam intensity is consistent with the long side direction NH.

[0159] In the case of using slit or elliptical optical systems, such as Figure 23 As shown in (c), in the region opposite to the laser incident surface near the focal point, the beam shape has a direction NH (refer to) that is parallel to the long side of the region on the laser incident surface side. Figure 22 (a) NH has the same long side direction. In Figure 23 The beam intensity distribution within the plane of the beam shape in (c) (the plane at the Z-direction position opposite to the laser incident surface near the focal point) becomes a beam with a stronger intensity distribution in the long side direction NH, and the direction of stronger beam intensity coincides with the long side direction NH. In the case of using a slit or elliptical optical system, such as... Figure 23 As shown in (b), at the focal point, the beam shape has a long side direction NH (refer to) relative to the region on the side of the laser incident surface. Figure 23 (a) is perpendicular to the long side direction NH0. Figure 23 The beam intensity distribution in the plane of the beam shape of (b) (in the plane of the Z-direction position of the focusing point) becomes a strong intensity distribution in the long side direction NH0, and the direction of the strong beam intensity is consistent with the long side direction NH0.

[0160] When using this slit or elliptical optical system, the beam shape outside the focal point becomes a shape with its long side facing outwards. This beam shape outside the focal point is the beam shape that is the object of this embodiment. That is, a portion of the focal region C that is the object of this embodiment includes the region near the laser incident surface near the focal point. The beam shape that is the object of this embodiment is... Figure 23 The beam shape shown in (a).

[0161] During finishing processing, the control unit 6 controls the rotation of the stage 2, the irradiation of the laser L from the irradiation unit 3, the beam shape, and the movement of the focusing area C. The control unit 6 can perform various controls based on rotation information (hereinafter also referred to as "θ information") related to the amount of rotation of the stage 2. The θ information can be obtained from the drive amount of the drive device that rotates the stage 2, or from other sensors. The θ information can be obtained using various known methods. Here, the θ information includes the rotation angle based on the state of the object 11 when it is located in the 0° direction.

[0162] The control unit 6, while rotating the stage 2 and positioning the focusing area C along line A (the periphery of the effective area R) of the object 11, controls the start and stop of the irradiation of the laser L of the irradiation unit 3 based on θ information, thereby performing periphery treatment to form a modified area along the periphery of the effective area R.

[0163] The control unit 6 does not rotate the stage 2, but irradiates the removal area E with laser L, and moves the focusing area C of the laser L, thereby performing a removal process that forms a modified area in the removal area E.

[0164] The control unit 6 controls at least one of the following: the rotation of the stage 2, the irradiation of the laser L from the irradiation unit 3, and the movement of the focusing area C, by fixing the spacing between the multiple modification points contained in the modification area (the interval between adjacent modification points in the processing travel direction).

[0165] The control unit 6 obtains the reference position (0° position) of the rotation direction of the object 11 and the diameter of the object 11 from the image captured by the alignment camera (not shown). The control unit 6 controls the movement of the irradiation unit 3 such that the irradiation unit 3 can be moved along the X direction to the rotation axis Cx of the stage 2.

[0166] Next, an example of finishing processing will be described. First, the object 11 is placed on the stage 2 with the first surface 11a serving as the incident surface of the laser L. A support substrate or adhesive tape is adhered to the second surface 11b of the object 11, which houses the functional components, for protection.

[0167] Next, finishing processes are carried out. During the finishing process, the control unit 6 performs peripheral treatment. Specifically, as follows... Figure 24 As shown in (a), while the stage 2 rotates at a certain speed and the focusing area C is positioned along the periphery of the effective area R of the object 11, the start and stop of the laser L irradiation of the irradiation unit 3 are controlled based on θ information. Thus, as Figure 24 (b) and Figure 24 As shown in (c), a modified region 12 is formed along line A (the periphery of the effective region R). The formed modified region 12 includes a modification point and a crack extending from the modification point.

[0168] During the finishing process, the removal process is carried out by control unit 6. Specifically, as follows: Figure 25 As shown in (a), without rotating the stage 2, laser L is irradiated in the removal area E, and the irradiation unit 3 is moved along the X direction, causing the focusing area C of the laser L to move relative to the object 11 in the X direction. After rotating the stage 2 by 90°, laser L is irradiated in the removal area E, and the irradiation unit 3 is moved along the X direction, causing the focusing area C of the laser L to move relative to the object 11 in the X direction.

[0169] Therefore, as Figure 25As shown in (b), the modified region 12 is formed by extending a line along which region E is divided into four equal parts when viewed from the Z direction. The formed modified region 12 includes a modification point and a crack extending from the modification point. The crack may reach at least either the first surface 11a or the second surface 11b, or it may not reach at least either the first surface 11a or the second surface 11b. Then, as... Figure 26 (a) and Figure 26 As shown in (b), the removal region E is removed, with the modified region 12 as the boundary, by means of, for example, a jig or air. Thus, a semiconductor element 11K is formed from the object 11.

[0170] Next, as Figure 26 As shown in (c), the release surface 11c of the semiconductor element 11K is finished by grinding or polishing with an abrasive material KM such as a whetstone. This polishing process can be simplified when the object 11 is removed by etching. As a result, the semiconductor element 11M is obtained.

[0171] Next, a more detailed explanation will be given regarding the finishing and processing. For example... Figure 27 As shown, object 11 is plate-shaped. Object 11 has a crystalline structure comprising: a (100) facet, a (110) facet, another (110) facet, a first crystalline orientation K1 orthogonal to one (110) facet, and a second crystalline orientation K2 orthogonal to the other (110) facet. The first facet 11a of object 11 is the (100) facet. Object 11 is supported on stage 2 such that the (100) facet (i.e., the first facet 11a) serves as the incident surface of laser L. Object 11 is, for example, a silicon wafer formed of silicon. The (110) facet is the crack facet. The first crystalline orientation K1 and the second crystalline orientation K2 are the crack directions, i.e., the directions in which cracks in object 11 are most likely to extend. The first crystalline orientation K1 and the second crystalline orientation K2 are orthogonal to each other.

[0172] In object 11, there is a positioning object 11n. For example, the position of the positioning object 11n relative to the 0° direction of object 11 is related to the θ direction (the rotation direction of the stage 2 about the rotation axis Cx). The position in the 0° direction refers to the position of object 11 that serves as a reference in the θ direction. For example, the positioning object 11n is a notch formed on the outer edge. Furthermore, the positioning object 11n is not particularly limited; it can be the orientation plane of object 11 or a pattern of a functional element. In the example of the icon, the positioning object 11n is located at the 0° direction of object 11. In other words, the positioning object 11n is located at a position where the outer edge of object 11 is orthogonal to the second crystal orientation K2.

[0173] On the object 11, a line A is set as a predetermined trimming line. Line A is a line that is intended to form the modified area 12. Line A extends in a loop on the inner side of the outer edge of the object 11. Here, line A extends in a loop shape. Line A is set at the boundary between the effective area R and the removal area E of the object 11. The setting of line A can be performed in the control unit 6. Although line A is a virtual line, it can also be an actually drawn line. Line A can also be specified by coordinates.

[0174] The control unit 6 acquires object information about the object 11. This object information includes, for example, information about the crystal orientation of the object 11 (first crystal orientation K1 and second crystal orientation K2), alignment information about the object 11's position in the 0° direction, and alignment information about the diameter of the object 11. The control unit 6 can acquire this object information based on images captured by an alignment camera, user input, or input from external communications.

[0175] Additionally, the control unit 6 acquires line information about line A. This line information includes information about line A itself, and information about the direction of movement (also called the "processing travel direction") when the focusing area C is moved relatively along line A. For example, the processing travel direction is the tangential direction of line A through the focusing area C located on line A. The control unit 6 can acquire this line information based on user operation or input from external communication, etc.

[0176] Furthermore, the control unit 6, based on the acquired object information and line information, determines the orientation of the long side direction when the focusing area C is moved relative to the line A, and makes the long side direction of the beam shape intersect the processing travel direction. Specifically, the control unit 6, based on the object information and line information, determines the orientation of the long side direction NH as a first orientation and a second orientation. The first orientation is the orientation of the long side direction of the beam shape when the focusing area C is moved relative to the line A1 in the first region. The second orientation is the orientation of the long side direction of the beam shape when the focusing area C is moved relative to the line A2 in the second region. Hereinafter, the "orientation of the long side direction of the beam shape" will be referred to simply as the "orientation of the beam shape".

[0177] Region A1 is an arc-shaped region. For example, when the point where the second crystal orientation K2 intersects line A is set to 0°, the point where the first crystal orientation K1 intersects line A is set to 90°, and the point between 0° and 90° of line A is set to 45°, it includes the following regions: from 0° to 45°, from 90° to 135°, from 180° to 225°, and from 270° to 315°. Region A2 is an arc-shaped region, including the following regions: from 45° to 90°, from 135° to 180°, from 225° to 270°, and from 315° to 360°. Furthermore, in this case, the points at 45° and 225° are the points where the third crystal orientation K3, which is orthogonal to the (100) plane, is orthogonal to line A, and the points at 135° and 315° are the points where the fourth crystal orientation K4, which is orthogonal to the (100) plane, is orthogonal to line A.

[0178] As described above, line A contains multiple first regions A1 and multiple second regions A2 arranged alternately every 45° counterclockwise. However, the aforementioned angular range of the first regions A1 and second regions A2 can be arbitrarily changed depending on where the 0° point is set. For example, if the point where the first crystal orientation K1 is orthogonal to line A is set to 0° (if the aforementioned 90° point is set to 0°), then the first regions A1 and second regions A2 are angular ranges rotated 90° from the aforementioned angular range. Furthermore, if the 0° point is set as described above, the point 45° clockwise from the 0° point, i.e., the 315° point, can be renamed the -45° point. Additionally, the point at the boundary (e.g., 45°) between the first regions A1 and the second regions A2 can be included in either the first region A1 or the second region A2, or it can be included in both.

[0179] Region A1, when the focusing area C is moved relative to line A, includes areas with a processing angle of 0° to 45° or -90° to -45° as described later. Region A2, when the focusing area C is moved relative to line A, includes areas with a processing angle of 45° to 90° or -45° to 0° as described later.

[0180] like Figure 28As shown in (b), the processing angle α is the angle between the processing travel direction ND and the first crystal orientation K1. The processing angle α is viewed from the Z direction, which intersects the incident surface of the laser L (i.e., the first surface 11a), with the counter-clockwise angle considered positive (+) and the clockwise angle considered negative (-). The processing angle α can be obtained based on the θ information, object information, and line information of the stage 2. For example, if the focusing area C is moved relative to the first region A1, the processing angle α can be considered to be 0° to 45° or -90° to -45°. Similarly, if the focusing area C is moved relative to the second region A2, the processing angle α can be considered to be 45° to 90° or -45° to 0°.

[0181] The first orientation and the second orientation are orientations that are inclined relative to the machining direction ND, in a manner that is closer to the larger (farther) angle between the first crystal orientation K1 and the second crystal orientation K2 and the machining direction ND.

[0182] The first and second orientations, when the processing angle α is 0° to 90°, are as follows: The first orientation is an orientation in which the long side direction NH is inclined towards the side approaching the second crystallization orientation K2 relative to the processing travel direction ND. The second orientation is an orientation in which the long side direction NH is inclined towards the side approaching the first crystallization orientation K1 relative to the processing travel direction ND. For example, the first orientation is an orientation in which the processing travel direction ND is inclined towards the side approaching the second crystallization orientation K2 by 10° to 35°. The second orientation is, for example, an orientation in which the processing travel direction ND is inclined towards the side approaching the first crystallization orientation K1 by 10° to 35°.

[0183] The first orientation is the orientation of the focusing region C when the beam angle β is +10° to +35°. The second orientation is the orientation of the focusing region C when the beam angle β is -35° to -10°. The beam angle β is the angle between the machining travel direction ND and the long side direction NH. The beam angle β is determined by viewing the laser from the Z direction, which intersects the incident surface of the laser L (i.e., the first surface 11a), with counter-clockwise angles considered positive (+) and clockwise angles considered negative (-). The beam angle β can be obtained based on the orientation of the focusing region C and the machining travel direction ND.

[0184] Control unit 6 controls the start and stop of laser processing on object 11. Control unit 6 performs a first processing step, in which the focusing area C is moved relative to the first region A1 of line A to form a modified region 12, and the formation of the modified region 12 is stopped outside the first region A1 of line A. Control unit 6 performs a second processing step, in which the focusing area C is moved relative to the second region A2 of line A to form a modified region 12, and the formation of the modified region 12 is stopped outside the second region A2 of line A.

[0185] The formation and cessation of the modified region 12 in the control unit 6 can be switched as follows. For example, in the irradiation unit 3, the start and stop (ON / OFF) of the irradiation (output) of the laser L are switched, thereby switching the formation and cessation of the formation of the modified region 12. Specifically, when the laser oscillator is composed of a solid-state laser, the ON / OFF of the Q-switch (AOM (acoustic optical modulator), EOM (electro-optical modulator), etc.) provided in the resonant cavity is switched, thereby switching the start and stop of the irradiation of the laser L at high speed. When the laser oscillator is composed of a fiber laser, the ON / OFF of the output of the semiconductor laser constituting the seed laser and the amplifier (excitation) laser is switched, thereby switching the start and stop of the irradiation of the laser L at high speed. When the laser oscillator uses an external modulation element, the ON / OFF of the external modulation element (AOM, EOM, etc.) provided outside the resonant cavity is switched, thereby switching the ON / OFF of the irradiation of the laser L at high speed.

[0186] Alternatively, the formation and cessation of the modified region 12 controlled by the control unit 6 can be switched as follows: For example, the formation and cessation of the modified region 12 can be switched by controlling a mechanical mechanism such as a shutter to close the optical path of the laser L. The formation of the modified region 12 can also be stopped by switching the laser L to CW (continuous wave) light. The formation of the modified region 12 can also be stopped by displaying the focusing state of the laser L as a pattern that cannot be modified (e.g., a rough pattern that scatters the laser light) on the liquid crystal layer 76 of the spatial light modulator 7. The formation of the modified region 12 can also be stopped by controlling the output adjustment unit such as an attenuator to reduce the output of the laser L in a way that prevents the formation of the modified region 12. The formation of the modified region 12 can also be stopped by switching the polarization direction. The formation of the modified region 12 can also be stopped by scattering (dispersing) the laser L in a direction other than the optical axis.

[0187] Control unit 6 adjusts the orientation of the focusing region C by controlling the spatial light modulator 7. When performing the first processing step, control unit 6 adjusts the orientation of the focusing region C to achieve the first orientation. When performing the second processing step, control unit 6 adjusts the orientation of the focusing region C to achieve the second orientation. As an example, control unit 6 adjusts the long side direction NH of the focusing region C by varying the processing travel direction ND within a range of ±35°.

[0188] The following finishing process is performed in the laser processing apparatus 1 described above.

[0189] During the finishing process, firstly, with the alignment camera positioned directly above the alignment object 11n of the object 11 and the camera's focus aligned with the alignment object 11n, the stage 2 is rotated and the irradiation unit 3 equipped with the camera is moved along the X and Y directions.

[0190] Next, a positioning camera is used to take a picture. Based on the image captured by the camera, the position of the object 11 in the 0° direction is obtained. Through the control unit 6, object information and line information are obtained based on the image captured by the camera and input from user operation or external communication. The object information includes positioning information for the desired position and diameter of the object 11 in the 0° direction. As described above, the position of the object 11n in the 0° direction has a certain relationship with the θ direction, so the position of the object 11n in the 0° direction can be obtained from the captured image, thereby obtaining the position in the 0° direction. The diameter of the object 11 can be obtained based on the image captured by the camera. In addition, the diameter of the object 11 can also be set by user input.

[0191] Next, based on the obtained object information and line information, the control unit 6 determines the orientation of the long side direction NH of the focusing area C when the focusing area C is moved relative to the line A, namely the first orientation and the second orientation.

[0192] Next, the stage 2 is rotated so that the object 11 is positioned at 0°. In the X direction, the irradiation unit 3 is moved along the X and Y directions with the focusing area C positioned at a predetermined location. The predetermined location is, for example, a predetermined position on line A of the object 11.

[0193] Next, the stage 2 begins to rotate. Tracking of the first surface 11a of the range sensor (not shown) begins. Furthermore, before the range sensor begins tracking, it is confirmed that the position of the focusing area C is within the detectable range of the range sensor. At the point when the rotational speed of the stage 2 becomes constant, irradiation by the laser L from the irradiation unit 3 begins.

[0194] While rotating the stage 2, the control unit 6 switches the irradiation of the laser L on / off, thereby... Figure 28 As shown in (a), the focusing region C is relatively moved along the first region A1 in line A to form the modified region 12, and the formation of the modified region 12 stops in the region outside the first region A1 of line A (first processing step). Figure 28 As shown in (b), when the first processing step is performed, the orientation of the focusing area C is adjusted to the first orientation by the control unit 6. That is, the orientation of the focusing area C in the first processing step is fixed to the first orientation.

[0195] Next, while rotating the stage 2, the control unit 6 switches the ON / OFF state of the laser L's irradiation, thereby... Figure 29 As shown in (a), the focusing region C is relatively moved along the second region A2 in line A to form the modified region 12, and the formation of the modified region 12 stops in the region other than the first region A1 in line A (second processing step). Figure 29 As shown in (b), when performing the second processing step, the orientation of the focusing area C is adjusted to the second orientation by the control unit 6. That is, the orientation of the focusing area C in the second processing step is fixed to the second orientation.

[0196] The Z-direction position of the modified position is changed to repeatedly perform the first and second processing steps described above. As described above, multiple rows of modified regions 12 are formed in the Z-direction along line A of the periphery of the effective region R inside the object 11.

[0197] [First Embodiment of Laser Processing]

[0198] The above has explained the insights regarding the formation of oblique cracks and an example of finishing processing. Here, an embodiment of laser processing for the formation of oblique cracks during finishing processing will be described. Figure 30 , is a diagram showing the object to be laser-processed according to one embodiment. Figure 30 (a) is a top view. Figure 30 (b) is a side view. Figure 31 ,yes Figure 30 The cross-sectional view of the object shown.

[0199] like Figure 30 , 31As shown, object 100 includes: object 11 as described above, and object 11R with different components from object 11. Object 11R is, for example, a silicon wafer. Object 11 contains multiple functional elements and includes a component layer 110 formed on a second surface 11b. Object 11R contains multiple functional elements and includes a component layer 110R formed on a first surface 11Ra of object 11R. Object 11 and object 11R are arranged and bonded together with component layers 110 and 110R facing each other to form object 100.

[0200] Here, a modified region 12 and a crack 13 extending from the modified region 12 are formed on the object 11. A finishing process is performed, using these modified regions 12 and cracks 13 as boundaries, to remove the removal region E of the object 11. More specifically, the object 11 includes a first portion 15A and a second portion 15B arranged sequentially from the side opposite to the first surface 11a of the incident surface of the laser L, to the side of the second surface 11b (opposite surface). Furthermore, in the first portion 15A, the modified region 12 is formed by creating a crack 13 extending obliquely relative to the Z direction (hereinafter referred to as "oblique crack"), and in the second portion 15B, the modified region 12 is formed by creating a crack 13 extending along the Z direction (hereinafter referred to as "vertical crack"). In addition, Figure 31 Line R1 is a predetermined line indicating the formation of oblique cracks, and line R2 is a predetermined line indicating the formation of vertical cracks.

[0201] Therefore, at least during the processing of Part 15A, the above-mentioned finishing process is combined with the process for generating oblique cracks. That is, during the processing of Part 15A, the beam shape is formed with the long side direction NH tilted relative to the processing direction ND, so as to approach the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the processing direction ND, and the modified region 12 and the crack 13 are formed along line A, and the crack 13 is made into an oblique crack.

[0202] More specifically, when processing the first region A1 of line A, such as Figure 28 As shown in (b), laser L is formed in such a way that it becomes the focusing region C of the first shape Q1 in the first orientation. When processing the second region A2 of line A, as shown... Figure 29 As shown in (b), laser L is formed in such a way that it becomes the focusing region C of the second shape Q2 in the second orientation. When performing this processing, a processing test is conducted as follows.

[0203] Figure 32 ,yes Figure 30 A top view of the object shown. For example... Figure 32As shown, here, for the second region A2 in line A, from the intersection of line A and the second crystal orientation K2 (0°) to the intersection of line A and the fourth crystal orientation K4 (-45°), cross-sectional observation is performed under the following conditions: when the processing direction ND is forward (ND1) and the focusing region C is relatively moved; and when the processing direction ND is reverse (ND2) and the focusing region C is relatively moved. Here, because the second region A2 is processed, the focusing region C becomes... Figure 29 The second shape Q2 is shown in (b). Furthermore, the direction of the oblique crack extension CD is from the center side of the object 11 outwards (see reference). Figure 29 (b)

[0204] Therefore, as Figure 29 As shown in (b), when the processing direction ND is forward ND1, the orientation of the long side direction NH of the focusing region C, which is inclined with respect to the processing direction ND, is the same as the extension direction CD of the oblique crack. On the other hand, when the processing direction ND is reverse ND2 (making the direction of the arrow of the processing direction ND opposite), the orientation of the long side direction NH, which is inclined with respect to the processing direction ND, is opposite to the extension direction CD of the oblique crack. Furthermore, forward ND1 is a counterclockwise direction, and reverse ND2 is a clockwise direction.

[0205] Figure 33 and Figure 34 , is a cross-sectional photograph showing the processing result. Figure 33 The images show the machining results along the ND1 direction. (a) to (d) are cross-sectional photographs of the points at 0°, -15°, -30°, and -45°, respectively. Additionally, Figure 34 , representing the machining results of ND2 in the reverse direction, (a)~(d) are cross-sectional photographs of the points at 0°, -15°, -30° and -45°, respectively.

[0206] like Figure 33 , 34 As shown, machining in the forward direction ND1, where the orientation of the long side direction NH and the extension direction CD of the oblique crack are on the same side as the machining travel direction ND, yields good machining results from 0° to -45°. However, machining in the reverse direction ND2, where the orientation of the long side direction NH and the extension direction CD of the oblique crack are on opposite sides of the machining travel direction ND, yields poor results at the point -45°. Figure 34(d) indicates that the unevenness FN below the surface occurs, confirming a decrease in quality. This suggests that the relationship between the orientation of the long side direction NH relative to the machining travel direction ND and the direction CD from which the diagonal crack extends relative to the machining travel direction ND affects the machining quality. Based on this understanding, further machining tests were conducted.

[0207] Figure 35 This is a schematic diagram used to illustrate the processing test. Figure 36 This is a schematic diagram illustrating the relationship between the machining travel direction, beam shape, and oblique cracking in a machining test. For example... Figure 35 , 36 As shown, in this processing test, when viewed from the Z direction, the processing direction ND is taken as the direction that is 45° to the (110) surface. For each of the forward direction ND1 and the reverse direction ND2, processing is performed to make the extension direction CD of the oblique crack become the positive direction CD1 and the reverse direction CD2. That is, with the forward and reverse directions of the processing direction ND as a pair, and the positive and negative directions of the extension direction CD of the oblique crack as a pair, for a total of four combinations, processing is further performed to make the beam shape of the focusing area C become the first shape Q1 and the second shape Q2 (a total of eight sets of processing).

[0208] Figure 37 , means Figure 35 , 36 The table shows the results of the processing tests. (See table below.) Figure 37 As shown, for a total of eight processing steps, when the extension direction CD of the oblique crack is the positive direction CD1, good processing results are obtained when the beam shape of the focusing region C becomes the second shape Q2 and the processing direction ND is the forward direction ND1, and when the beam shape of the focusing region C becomes the first shape Q1 and the processing direction ND is the reverse direction ND2. Figure 37 Table "A").

[0209] Furthermore, for the eight sets of processing, when the extension direction CD of the oblique crack becomes the opposite direction CD2, good processing results are obtained when the beam shape of the focusing region C becomes the first shape Q1 and the processing travel direction ND is in the forward direction ND1, and when the beam shape of the focusing region C becomes the second shape Q2 and the processing travel direction ND is in the reverse direction ND2. It can be understood that, at least when processing points at 45°, adjusting the forward or reverse direction of the processing travel direction ND, and ensuring that the orientation of the long side direction NH of the focusing region C relative to the processing travel direction ND is the same as the extension direction CD of the oblique crack, yields good processing results.

[0210] Furthermore, the point at 45° is the point at which the second crystal orientation K2 orthogonal to line A is 0°, and is the point at which the third crystal orientation K3 orthogonal to line A is orthogonal to the (100) plane. Similarly, the point at -45° is the point at which the fourth crystal orientation K4 orthogonal to line A is orthogonal to the (100) plane.

[0211] Based on the above insights, further processing experiments will be conducted. Figure 38 , is a table that represents the results of processing tests. Figure 38 Among the conditions shown in the table, the conditions that make the beam shape become shape Q1 in region A1 and shape Q2 in region A2, namely, the conditions IR1 and IR2 where the long side direction NH of the focusing region C is tilted with respect to the processing travel direction ND and the extension direction CD of the oblique crack are on the same side, can yield good processing results. Figure 38 The table is rated "A" or "B". Furthermore, Figure 38 The evaluations shown are in the order of "A", "B", "C", "D", and "E" as good (i.e., "A" is the best and "E" is the worst).

[0212] Condition IR1 is defined as follows: with the point where the first crystal orientation K1 intersects line A at 0°, for the second region A2 from 0° to -45°, the processing direction ND is set to the forward direction ND1, and the beam shape of the focusing region C becomes the second shape Q2. Condition IR2 is defined as follows: with the point where the first crystal orientation K1 intersects line A at 0°, for the first region A1 from -45° to -90°, the processing direction ND is set to the reverse direction ND2, and the beam shape of the focusing region C becomes the first shape Q1.

[0213] on the other hand, Figure 38 Of the conditions shown in the table, as long as the beam shape becomes shape Q1 in region A1 and shape Q2 in region A2, even conditions IR3 and IR4, where the orientation of the long side direction NH of the focusing region C is tilted relative to the processing travel direction ND and the extension direction CD of the oblique crack, although worse than conditions IR1 and IR2, still yield generally good processing results except for the point at -45°. On the other hand, Figure 38 Among the conditions shown in the table, condition IR5, which makes the beam shape become the second shape Q2 in region A1, and condition IR6, which makes the beam shape become the first shape Q1 in region A2, cannot produce good overall results regardless of whether the processing direction ND is forward or reverse.

[0214] also, Figure 39 (a) corresponds to Figure 38 The rating "E" in the table Figure 39 (b) corresponds to Figure 38 The rating "D" in the table Figure 39 (c) corresponds to Figure 38 The rating "C" in the table Figure 39 (d) corresponds to Figure 38 The rating "B" in the table Figure 39 (e) corresponds to Figure 38 An example of a cross-sectional photograph of a rating "A" in the table. For example... Figure 39 As shown, ratings "A" and "B" indicate a good processing result where unevenness does not form on the surface. Rating "C" indicates a slight unevenness that reaches the surface, but is generally a good result. On the other hand, ratings "D" and "E" indicate relatively more unevenness reaching the surface, indicating a poor result.

[0215] according to Figure 38 , 39 The results of the processing tests shown confirm that the material was produced by... Figure 37 The insights derived from the processing test results shown are correct.

[0216] In this embodiment, laser processing is performed based on the above insights. Here, firstly, the first part 15A of the object 11 (refer to...) is processed. Figure 31 The processing involves rotating the stage 2 while switching the ON / OFF state of laser L irradiation via the control unit 6, thereby achieving the desired effect. Figure 40 As shown in (a), the focusing region C is moved relative to the first region A1 in line A to form the modified region 12, and the formation of the modified region 12 is stopped in the region outside the first region A1 in line A (the second region A2) (first processing).

[0217] like Figure 40 As shown in (b), in the first processing, the rotation direction of the stage 2 is controlled by the movement unit 4 of the control unit 6, thereby making the processing travel direction ND the reverse direction ND2. Furthermore, the first processing is the processing of the first region A1, therefore, the laser L caused by the spatial light modulator 7 is shaped under the control of the control unit 6, thereby making the beam shape of the focusing region C the first shape Q1. Moreover, here, it is tilted outward from the center of the object 11 in the Z direction towards the second surface 11b (see reference). Figure 31 This makes the direction of the oblique crack extension CD become the positive direction CD1.

[0218] The method for forming oblique cracks will be explained in detail here. That is, in the first processing step, such as... Figure 41 As shown, the position of the focusing region C1 is set at a first Z position Z1 in the Z direction, which intersects the incident surface of the laser L1 of the object 11, i.e., the first surface 11a. The focusing region C1 is then moved relative to the object 11 along line A (X direction), thereby forming a modified region (first modified region) 12a and a crack (first crack) 13a extending from the modified region 12a (first formation) on the object 11. In this first formation, the position of the focusing region C1 is set at a first Y position Y1 in the Y direction, which is along the first surface 11a and intersects the X direction.

[0219] Furthermore, in the first processing, the position of the focusing region C2 of laser L2 in the Z direction is set to a second Z position Z2, which is closer to the first surface 11a (incident surface) than the first Z position Z1 of the first-formed focusing region C1. The focusing region C2 is then moved relative to the first surface 11a (incident surface) along line A (X direction) to form a modified region 12b (second modified region) and a crack (second crack) 13b extending from the modified region 12b (second formation). In this second formation, the position of the focusing region C2 in the Y direction is formed to a second Y position Y2, which is shifted from the first Y position Y1 of the focusing region C1. In addition, in the second formation, the beam shape of the focusing region C2 within the YZ plane S, which includes both the Y and Z directions, is modulated by the laser L2 into an inclined shape that is tilted in the shifting direction, at least closer to the first surface 11a than the center of the focusing region C2 (when viewed from the Z direction, the beam shape of the focusing region C2 is the first shape Q1). Therefore, a diagonal crack 13 is formed in the YZ plane S, pointing in the direction of displacement. The control of the beam shape in the YZ plane S is as described in the above-mentioned explanation of the diagonal crack.

[0220] Furthermore, in this first formation, similar to the second formation, the beam shape of the focusing region C1 within the YZ plane S, which includes the Y and Z directions, is such that the laser L1 is modulated into an inclined shape tilted towards the shift direction, at least closer to the first plane 11a than the center of the focusing region C1 (in this case, when viewed from the Z direction, the beam shape of the focusing region C1 is the first shape Q1). Based on the above, as... Figure 41 As shown in (b), in the first region A1 of line A, cracks 13a and 13b connect, forming obliquely extending cracks 13 (oblique cracks 13F) that extend throughout the modified regions 12a and 12b. The oblique cracks 13F may or may not reach the second surface 11b of the object 11 (this can be appropriately set according to the required processing state).

[0221] Furthermore, lasers L1 and L2, for example, can be modulated by displaying a pattern for branching laser L on the spatial light modulator 7, thereby splitting laser L into two beams. In this case, the first formation and the second formation are performed simultaneously. However, lasers L1 and L2 can also be different lasers, in which case the first formation and the second formation are performed at their respective points in time. Additionally, focusing regions C1 and C2 are each focusing regions of lasers L1 and L2 corresponding to the focusing region C of laser L.

[0222] On the other hand, in this embodiment, while rotating the stage 2, the control unit 6 switches the ON / OFF state of the laser L's irradiation, thereby achieving... Figure 42 As shown in (a), the focusing region C is moved relative to the second region A2 in line A to form the modified region 12, and the formation of the modified region 12 is stopped in the region outside the second region A2 in line A (the first region A1) (the second processing).

[0223] like Figure 42 As shown in (b), in the second processing, the rotation direction of the stage 2 is controlled by the movement unit 4 of the control unit 6, so that the processing travel direction ND becomes the forward direction ND1. That is, between the first processing and the second processing, the forward and reverse directions of the processing travel direction ND (forward direction ND1 or reverse direction ND2) are switched. In addition, the second processing is the processing of the second region A2, so the laser L caused by the spatial light modulator 7 is shaped by the control unit 6, so that the beam shape of the focusing region C becomes the second shape Q2. Furthermore, here, it is tilted in the direction from the center of the object 11 outward in the Z direction toward the second surface 11b (see reference). Figure 31 This makes the direction of the oblique crack extension CD become the positive direction CD1.

[0224] The method for forming oblique cracks will be explained in detail here. That is, in the second processing step, such as... Figure 43 As shown in (a), with respect to the Z direction intersecting the incident surface of the laser L1 of the object 11, i.e., the first surface 11a, the position of the focusing region C1 is set at the first Z position Z1, and the focusing region C1 is moved relative to the line A (X direction), thereby forming a modified region (first modified region) 12a and a crack (first crack) 13a extending from the modified region 12a (first formation) on the object 11. In this first formation, with respect to the Y direction intersecting the X direction along the first surface 11a, the position of the focusing region C1 is set at the first Y position Y1.

[0225] Furthermore, in the second formation, the position of the focusing region C2 of the laser L2 in the Z direction is set at a second Z position Z2, which is closer to the first surface 11a (incident surface) than the first Z position Z1 of the focusing region C1 formed in the first formation. The focusing region C2 is then moved relative to the first surface 11a (incident surface) along line A (X direction) to form a modified region 12b (second modified region) and a crack (second crack) 13b extending from the modified region 12b (second formation). In this second formation, the position of the focusing region C2 in the Y direction is set at a second Y position Y2, which is shifted from the first Y position Y1 of the focusing region C1. In addition, in the second formation, the beam shape of the focusing region C2 within the YZ plane S, which includes both the Y and Z directions, is modulated by the laser L2 into an inclined shape that is tilted towards the shifting direction, at least closer to the first surface 11a than the center of the focusing region C2 (when viewed from the Z direction, the beam shape of the focusing region C2 is the second shape Q2). As a result, an oblique crack 13 is formed in the YZ plane S, pointing in the direction of displacement.

[0226] Furthermore, in this first formation, similar to the second formation, the beam shape of the focusing region C1 within the YZ plane S, which includes the Y and Z directions, is such that the laser L1 is modulated into an inclined shape tilted towards the shift direction, at least closer to the first plane 11a than the center of the focusing region C1 (in this case, when viewed from the Z direction, the beam shape of the focusing region C1 is the second shape Q2). Based on the above, as... Figure 43 As shown in (b), in the second region A2 of line A, cracks 13a and 13b connect, forming obliquely extending cracks 13 (oblique cracks 13F) that extend throughout the modified regions 12a and 12b. Cracks 13 may or may not reach the second surface 11b of the object 11 (this can be appropriately set according to the required processing pattern). Furthermore, the modulation pattern used to make the beam shape oblique is as described above.

[0227] That is, the modulation pattern here contains a coma pattern for imparting coma aberration to the laser L, which is formed at least in the second stage. The control unit 6 controls the magnitude of the coma aberration in the coma pattern, thereby performing first pattern control to make the beam shape of the focusing region C2 into an inclined shape. As described above, imparting coma aberration to the laser L is the same as the offset of the spherical aberration correction pattern.

[0228] Therefore, the modulation pattern here includes a spherical aberration correction pattern Ps for correcting the spherical aberration of the laser L. At least in the second formation, the control unit 6 can also perform a second pattern control, which shifts the center Pc of the spherical aberration correction pattern Ps in the Y direction relative to the center of the entrance pupil surface 33a of the condenser lens 33, thereby making the beam shape of the condenser region C2 into an inclined shape.

[0229] Alternatively, in the second formation, the control unit 6 may also perform a third pattern control, which displays an asymmetric modulation pattern on the spatial light modulator 7 with respect to the axis Ax along the X direction, thereby making the beam shape of the focusing region C2 tilted. The asymmetric modulation pattern with respect to the axis Ax may be a modulation pattern PG1 to PG4 containing a grating pattern Ga, or a modulation pattern PE containing elliptical patterns Es and Ew (or may contain both).

[0230] That is, the modulation pattern here contains elliptical patterns Es and Ew, which are used to make the beam shape of the focusing area C in the XY plane become an elliptical shape with the X direction as the long side. In the second formation, the control unit 6 can also display the modulation pattern PE on the spatial light modulator 7 in a way that the intensity of the elliptical patterns Es and Ew is asymmetrical with respect to the axis Ax along the X direction, thereby performing the fourth pattern control for making the shape of the focusing area C2 into an inclined shape.

[0231] Furthermore, during the second formation, the control unit 6 may also display a modulation pattern (such as the aforementioned axial conical lens pattern PA) for forming multiple focusing regions C arranged along the shifting direction within the YZ plane S on the spatial light modulator 7, thereby performing a fifth pattern control to make the beam shape of the focusing region C tilted. These various patterns can also be arbitrarily combined and overlapped. That is, the control unit 6 can arbitrarily combine the first to fifth pattern controls to perform the operation.

[0232] Furthermore, the first formation and the second formation can be performed simultaneously (multi-focus processing) or sequentially (single-channel processing). That is, the control unit 6 can perform the first formation on, for example, the first region A1 of line A, and then perform the second formation. Alternatively, the control unit 6 can display a modulation pattern including a branching pattern for splitting laser L into lasers L1 and L2 on the spatial light modulator 7, thereby performing the first formation and the second formation simultaneously on, for example, the first region A1 of line A set on the object 11.

[0233] Next, in this embodiment, the second part 15B of the object 11 (see reference) will be performed. Figure 31 The processing of Part 2, 15B, does not necessarily involve the formation of oblique cracks; instead, vertical cracks are formed. Therefore, the processing of Part 2, 15B is performed in the same manner as the finishing process described above to form the modified regions 12c, 12d and the cracks (vertical cracks) 13c, 13d extending from them (see reference). Figure 45 In this case, in Part 2, 15B, it is not necessary to switch the direction of machining travel ND between Area 1, A1 and Area 2, and the first and second machining processes can be performed.

[0234] However, in the above-mentioned finishing process, in order to suppress the degradation of the finished surface quality, the beam shape is made into shape Q1 (first processing) during the processing of region A1, and the beam shape is made into shape Q2 (second processing) during the processing of region A2. However, in the second part 15B, the long side direction NH of the focusing region C can be moved along the processing travel direction ND (without tilting towards the processing travel direction ND), and the focusing region C can be continuously moved relative to each other throughout the entire line A without the ON / OFF irradiation of laser L at the boundary between region A1 and region A2, thereby forming modified regions 12c, 12d and cracks 13c, 13d. That is, other processing different from the first and second processing can also be performed in the second part 15B. Alternatively, in Part 2, 15B, the switching of the processing direction ND can be omitted, and the first Z processing and the second Z processing can be performed as different processes. In the first Z processing, the focusing region C is moved relative to each other along the first region A1 in line A, thereby forming modified regions 12c and 12d along the first region A1, and forming cracks 13c and 13d extending from the modified regions 12c and 12d along the Z direction. In the second Z processing, the focusing region C is moved relative to each other along the second region A2 in line A, thereby forming modified regions 12c and 12d along the second region A2, and forming cracks 13c and 13d extending from the modified regions 12c and 12d along the Z direction. In this case, in the first Z processing and the second Z processing, similarly to the first processing and the second processing, the laser L can be shaped such that, when viewed from the Z direction, the focusing region C has a long side direction NH, and for the processing travel direction NDD, this long side direction NH is tilted toward the direction that is closer to the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the processing travel direction ND.

[0235] Through the above processing, and as Figure 44 and Figure 45 As shown, the modified region 12 and cracks 13 are formed on the object 11, extending across the entirety of line A and approximately across the entirety of the Z direction. Specifically, as... Figure 45 As shown, in part 15A, there are oblique cracks 13a and 13b formed from the inner side of the bonding region between the element layer 110 of the object 11 and the element layer 110R of the object 11R, toward the outer edge 110e of the bonding region, as the object 11 moves from the first surface 11a to the second surface 11b. Furthermore, cracks 13c and 13d may be discontinuous and broken, or they may be continuous. Additionally, cracks 13b and 13c may be discontinuous and broken, or they may be continuous.

[0236] Next, the removal process is performed in the same manner as the trimming process described above. Specifically, without rotating the stage 2, laser L is irradiated in the removal area E, and the irradiation unit 3 is moved along the X direction, causing the focusing area C of the laser L to move relative to the object 11 in the X direction. After rotating the stage 2 by 90°, laser L is irradiated in the removal area E, and the irradiation unit 3 is moved along the X direction, causing the focusing area C of the laser L to move relative to the object 11 in the X direction.

[0237] Therefore, as Figure 46 As shown, viewed from the Z direction, along a line extending in a manner that divides the removed region E into four equal parts, the modified region 12 and the crack 13 extending from the modified region 12 are formed. Then, as... Figure 47 As shown in (a), the removal region E is removed by means of, for example, a jig or air, with the modified region 12 as the boundary. Thus, a semiconductor element 11K is formed from the object 11, resulting in an object 100K containing the semiconductor element 11K.

[0238] Next, the semiconductor element 11K is ground from the first surface 11a side. Here, the second portion 15B and a portion of the first portion 15A are removed. The removed portion of the first portion 15A is the portion where the modified regions 12a and 12b are formed. Thus, the remaining portion of the first portion 15A does not contain the modified regions 12a and 12b. If the object 11 is removed by etching, this grinding process can be simplified. As a result of the above, the semiconductor element 11M is formed, and an object 100M containing the semiconductor element 11M is obtained.

[0239] The laser processing described in this embodiment will be explained using the structure of the laser processing apparatus 1. Specifically, the laser processing apparatus 1 is an apparatus for irradiating a workpiece 11 with lasers L (lasers L1, L2) to form a modified region 12. It includes at least: a stage 2 for supporting the workpiece 11; an irradiation unit 3 for irradiating the workpiece 11 supported by the stage 2 with laser L; moving units 4 and 5 for moving the focusing regions C (focusing regions C1, C2) of the laser L relative to the workpiece 11; and a control unit 6 for controlling the moving units 4 and 5 and the irradiation unit 3. The irradiation unit 3 has a spatial light modulator 7, which shapes the laser L so that the focusing region C, when viewed from the Z direction, has a long side direction NH.

[0240] Furthermore, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 to perform the first processing (the first processing mentioned above), thereby causing the focusing area C (focusing areas C1 and C2) to move relative to the first area A1 in line A, thereby forming a modified area 12 (modified areas 12a and 12b) on the object 11 along the first area A1, and forming an oblique crack 13F extending obliquely in the Z direction from the modified area 12 toward the second surface 11b opposite to the incident surface of the object 11, i.e., the first surface 11a.

[0241] Furthermore, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 to perform the second processing (the second processing mentioned above), thereby causing the focusing area C (focusing area C1, C2) to move relative to the second area A2 in line A, thereby forming a modified area 12 (modified area 12a, 12b) on the object 11 along the second area A2, and forming oblique cracks 13F (cracks 13a, 13b) extending from the modified area 12 toward the second surface 11b.

[0242] In the first and second processing steps, the control unit 6 controls the spatial light modulator 7 to shape the laser L such that, when viewed from the Z direction, the focusing region C has a long side direction NH, and relative to the processing travel direction ND, the long side direction NH of the focusing region C is tilted towards the direction with the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the moving direction of the focusing region C, i.e., the processing travel direction ND. Furthermore, in the first and second processing steps, the control unit 6 controls the moving units 4 and 5 to switch the direction of the processing travel direction ND between the first and second processing steps so that, when viewed from the Z direction, the tilting direction of the long side direction NH is on the same side as the direction in which the oblique crack 13F extends relative to the processing travel direction ND.

[0243] Next, regarding the laser processing of this embodiment described above, the process steps of the laser processing method will be explained. That is, the laser processing method of this embodiment is a method for forming a modified region 12 by irradiating a workpiece 11 with lasers L (lasers L1, L2), and has a first processing step (the first processing described above), in which a focusing region C (focusing region C1, C2) is moved relative to the workpiece 11 along a first region A1 set in a line A, thereby forming a modified region 12 (modified region 12a, 12b) on the workpiece 11 along the first region A1, and forming oblique cracks 13F (cracks 13a, 13b) extending obliquely in the Z direction from the modified region 12 toward a second surface 11b opposite to the incident surface of the workpiece 11, i.e., the first surface 11a.

[0244] Furthermore, the laser processing method of this embodiment has a second processing step (the second processing described above), which involves moving the focusing region C (focusing regions C1, C2) relative to the second region A2 in line A, thereby forming a modified region 12 (modified regions 12a, 12b) on the object 11 along the second region A2, and forming oblique cracks 13F (cracks 13a, 13b) extending from the modified region 12 toward the second surface 11b.

[0245] In the first and second processing steps, the laser L is shaped such that, when viewed from the Z direction, the focusing region C has a long side direction NH, and with respect to the processing direction ND, the long side direction NH of the focusing region C is tilted towards the direction with the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the direction of movement of the focusing region C, i.e., the processing direction ND. Furthermore, in the first and second processing steps, the direction of the processing direction ND is switched between the first and second processing steps such that, when viewed from the Z direction, the tilting direction of the long side direction NH is on the same side as the direction in which the oblique crack 13F extends with respect to the processing direction ND.

[0246] As explained above, in the laser processing apparatus 1 and laser processing method of this embodiment, the object 11 has a crystalline structure comprising: a (100) surface, one (110) surface, another (110) surface, a first crystal orientation K1 orthogonal to one (110) surface, and a second crystal orientation K2 orthogonal to the other (110) surface. Furthermore, in both the case where a modified region 12 is formed on the object 11 along the first region A1 in line A that moves the focusing region C of the laser L (first processing, first processing step), and the case where a modified region 12 is formed on the object 11 along the second region A2 in line A (second processing, second processing step), the long side direction NH of the focusing region C is tilted relative to the processing travel direction ND with an orientation closer to the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the processing travel direction ND, thus shaping the laser L. Therefore, the quality reduction of the trimmed surface can be suppressed.

[0247] On the other hand, in the laser processing apparatus 1 and laser processing method of this embodiment, in the first processing and the second processing (the first processing step and the second processing step are the same (hereinafter the same)), an oblique crack 13F is formed that extends obliquely from the modified region 12 toward the second surface 11b of the object 11 relative to the Z direction (the direction intersecting the incident surface). Therefore, the relationship between the extension direction of the oblique crack 13F and the orientation of the long side direction NH of the focusing region C must be considered. Moreover, in the laser processing apparatus 1 and laser processing method of this embodiment, when viewed from the Z direction, the orientation of the oblique crack 13F is aligned with the extension side of the long side direction NH relative to the processing travel direction ND, and the forward and reverse directions of the processing travel direction ND are switched in the first processing and the second processing.

[0248] As a result, in both regions A1 and A2, the orientation of the long side direction NH of the focusing region C relative to the processing travel direction ND is the same as the extension side of the oblique crack 13F. Therefore, the relationship between the orientation of the long side direction NH of the focusing region C and the orientation of the oblique crack 13F is a combination that yields relatively good quality, and quality reduction can be suppressed. Thus, according to the laser processing apparatus 1 and laser processing method of this embodiment, quality reduction of the workpiece 11 can be suppressed, and oblique cracks can be formed.

[0249] Alternatively, in the laser processing apparatus 1 of this embodiment, the object 11 may include a first portion 15A and a second portion 15B arranged sequentially along the Z direction from the second surface 11b side. Furthermore, the control unit 6 performs the first and second processing steps for the first portion 15A while switching the processing direction ND forward and reverse, and performs the first and second processing steps for the second portion 15B without switching the processing direction ND, forming a modified region 12 (modified regions 12c, 12d) and cracks 13 (cracks 13c, 13d) extending from the modified region 12 along the Z direction in the second portion 15B. In this case, the switching of the processing direction ND is not performed during the first and second processing steps for the second portion 15B where cracks 13 along the Z direction are formed. Therefore, compared to switching the processing direction ND forward and reverse in the first and second processing steps, the time required for acceleration and deceleration of the relative movement of the focusing area C of the laser L can be reduced.

[0250] Alternatively, in the laser processing apparatus 1 of this embodiment, the control unit 6 may perform the first and second processing processes for the first part 15A while switching the direction of processing travel ND, and perform other processing processes (other processing) different from the first and second processing processes for the second part 15B. In other processing processes, the control unit 6 may also control the irradiation unit 3 and the moving units 4 and 5 to make the direction of processing travel ND the same throughout the entire line A and to move the focusing area C relative to each other along the line A, thereby forming a modified area 12 and a crack 13 extending from the modified area 12 along the Z direction on the object 11. In this case, compared with the case where the direction of processing travel ND is switched between the first area A1 and the second area A2 of the line A for the second part 15B, the time required for acceleration and deceleration of the relative movement of the focusing area C of the laser L can be reduced.

[0251] Furthermore, in other processing steps, the control unit 6 of the laser processing apparatus 1 of this embodiment can also control the spatial light modulator 7 to shape the laser L such that, when viewed from the Z direction, the focusing region C has a long side direction NH, and the long side direction NH of the focusing region C is along the processing travel direction ND. In this case, compared to the case where the laser L is shaped by varying the processing of the first region A1 and the second region A2 along the tilt line A of the focusing region C of the laser L in the process of forming the second portion 15B of the crack 13 along the Z direction, the processing of the control unit 6 is simplified.

[0252] Alternatively, in the laser processing apparatus 1 of this embodiment, the object 11 may include a joining region that joins with other components (object 11R). In the first and second processing steps, the control unit 6 forms an oblique crack 13F that slopes from the inner side of the joining region toward the outer edge 11e of the joining region as it moves from the first surface 11a toward the second surface 11b. In this case, when a portion of the object 11 bounded by the oblique crack 13F is removed from the object 11, leaving a residual portion of the object 11, it is possible to prevent the residual portion of the object 11 from extending outward across the joining region with other components.

[0253] Furthermore, in the laser processing apparatus 1 of this embodiment, the control unit 6 can perform a first forming process and a second forming process in the first processing and the second processing. In the first forming process (the first forming mentioned above), the position of the focusing region C1 is set at the first Z position Z1 in the Z direction, and the focusing region C1 is moved relative to the object 11 along line A, thereby forming the modified region 12a and the crack 13a extending from the modified region 12a. In the second forming process (the second forming mentioned above), the position of the focusing region C2 is set at the second Z position Z2 in the Z direction, which is closer to the first surface 11a than the first Z position Z1, and the focusing region C2 is moved relative to the object 11 along line A, thereby forming the modified region 12b and the crack 13b extending from the modified region 12b.

[0254] In the first forming process, the control unit 6 may set the position of the focusing region C1 in the Y direction, which intersects the processing travel directions ND and Z, as the first Y position Y1. In the second forming process, the control unit 6 sets the position of the focusing region C2 in the Y direction to the second Y position Y2, which is shifted from the first Y position Y1. Under the control of the spatial light modulator 7, the laser L2 is shaped such that the shape of the focusing region C2 in the YZ plane S, which includes the Y and Z directions, becomes an inclined shape that is at least tilted towards the shift direction from the first plane 11a further than the center of the focusing region C2, thereby forming an oblique crack 13b in the shift direction in the YZ plane S. In this way, an oblique crack tilted towards the Z direction can be appropriately formed.

[0255] Alternatively, in the laser processing apparatus 1 of this embodiment, the irradiation unit 3 may include a focusing lens 33 for focusing the laser L from the spatial light modulator 7 toward the object 11. In the second forming process, the control unit 6 modulates the laser L to an inclined shape by controlling a modulation pattern displayed on the spatial light modulator 7, thereby forming the laser L. In this case, the spatial light modulator 7 can be used to easily form the laser L.

[0256] In this embodiment, the laser processing apparatus 1 may also be configured to modulate a pattern containing a coma pattern for imparting coma aberration to the laser L. During the second forming process, the control unit 6 controls the magnitude of the coma aberration in the coma pattern, thereby performing first pattern control to make the shape of the focusing region C tilted. According to the inventors, in this case, the shape of the focusing region C within the YZ plane S is arc-shaped. That is, in this case, the shape of the focusing region C is tilted in the lateral displacement direction closer to the first surface 11a (incident surface) than the center Ca of the focusing region C, and tilted in the lateral direction opposite to the displacement direction, further away from the incident surface than the center Ca of the focusing region C. Even in this case, a diagonal crack 13F tilted in the displacement direction may be formed.

[0257] Alternatively, the laser processing apparatus 1 in this embodiment may also be an object 11 containing a first part 15A and a second part 15B arranged sequentially along the Z direction from the second surface 11b side. Furthermore, for the first part 15A, the control unit 6 performs the first processing and the second processing while switching the forward and reverse directions of the processing travel direction ND. For the second part 15B, the processing travel direction ND is not switched, and the first Z processing and the second Z processing are performed as different processing. In the first Z processing (the first Z processing mentioned above), the irradiation unit 3 and the moving units 4 and 5 are controlled to move the focusing area C relative to each other along the first region A1 in line A, thereby forming a modified region 12 on the object 11 along the first region A1 and forming a crack 13 extending from the modified region 12 along the Z direction. In the second Z processing (the second processing mentioned above), the irradiation unit 3 and the moving units 4 and 5 are controlled to move the focusing area C relative to each other along the second region A2 in line A, thereby forming a modified region 12 on the object 11 along the second region A2 and forming a crack 13 extending from the modified region 12 along the Z direction. In this case, also for part 2, 15B, compared to the case where the long side direction NH of the focusing region C is set in the first region A1 and the second region A2 according to the processing travel direction ND, and the clockwise and counterclockwise processing travel direction ND is switched in the first region A1 and the second region A2, the time required for acceleration and deceleration of the relative movement of the focusing region C of the laser L can be reduced.

[0258] Alternatively, the laser processing apparatus 1 in this embodiment may also include a modulation pattern containing a spherical aberration correction pattern for correcting the spherical aberration of the laser L. In the second formation process, the control unit 6 performs a second pattern control, which shifts the center of the spherical aberration correction pattern Ps in the Y direction relative to the center of the entrance pupil surface 33a of the condenser lens 33, thereby making the shape of the focusing region C tilted. According to the inventors' understanding, in this case, similar to the case using a coma aberration pattern, the shape of the focusing region C can be formed into an arc shape in the YZ plane S, and a slanted crack 13F tilted in the displacement direction can be formed.

[0259] Alternatively, in the laser processing apparatus 1 of this embodiment, during the second forming process, the control unit 6 performs a third pattern control, which displays an asymmetrical modulation pattern on the spatial light modulator 7 along the axis of the processing travel direction ND, thereby making the shape of the focusing region C tilted. According to the inventors' understanding, in this case, the entire shape of the focusing region C within the YZ plane S can be tilted in the displacement direction. Even in this case, a diagonal crack 13F tilted in the displacement direction can be formed.

[0260] Alternatively, the laser processing apparatus 1 in this embodiment may also have a modulation pattern containing an elliptical pattern. This pattern defines the shape of the focusing region C within the XY plane, which intersects the Y and Z directions, as an ellipse with the X direction as its longer side. In the second forming process, the control unit 6 displays the modulation pattern on the spatial light modulator 7 in a manner where the intensity of the elliptical pattern is asymmetrical about the axis along the X direction, thereby performing a fourth pattern control to make the beam shape tilted. According to the inventors' understanding, in this case, the shape of the focusing region C can also be formed into an arc shape within the YZ plane S, and a diagonal crack 13F tilted in the displacement direction can be formed.

[0261] Alternatively, in the laser processing apparatus 1 of this embodiment, during the second forming process, the control unit 6 displays a modulation pattern for forming focusing points CI of multiple lasers L arranged along the shifting direction in the YZ plane S on the spatial light modulator 7, thereby performing a fifth pattern control to make the shape of the focusing region C containing the multiple focusing points CI tilted. According to the inventors' understanding, in this case, a diagonal crack 13F tilted in the shifting direction can also be formed.

[0262] [Second Implementation of Laser Processing]

[0263] Next, other embodiments of laser processing for forming oblique cracks during finishing processes will be described. Figure 48 This is a diagram illustrating an object subjected to laser processing according to one embodiment. For example... Figure 48 As shown, the object to be laser-processed in this embodiment, like in the first embodiment, is the object 11 that is attached to the object 11R to form the object 100. However, in this embodiment, the angle ranges of the first region A1 and the second region A2 of line A are different from those in the first embodiment.

[0264] In the first embodiment, as an example, the boundary between the first region A1 and the second region A2 is set at a point at 45° or -45° where quality degradation of the trimmed surface is likely to occur. This is because, in the first embodiment, it is known that even at points at 45° or -45° where quality degradation is likely to occur, by adjusting the direction of the machining travel direction ND, during machining at points at 45° or -45°, the orientation of the long side direction NH of the focusing region C inclined with respect to the machining travel direction ND is aligned with the direction of the oblique crack 13F, thereby suppressing quality degradation.

[0265] On the other hand, such as Figure 38As shown in the table, for example, when the processing direction ND of the first region A1 and the second region A2 is both in the forward direction ND1 (refer to the first and third tables from the top), it can be seen that at the point of -45°, although there is a decrease in quality when the beam shape of the focusing region C is the first shape Q1 (refer to the third table from the top), good quality is obtained when it is the second shape Q2 (refer to the first table from the top), and good quality can still be obtained at the point of -50°.

[0266] Therefore, even if the machining direction ND of regions A1 and A2 is unified to the forward direction ND1, and the beam shape of the focusing region C is the second shape Q2 during machining in the angular range from approximately 0° to -50°, and the beam shape of the focusing region C is the first shape Q1 during machining in the angular range from approximately -50° to -90°, good machining quality can be obtained in all angular ranges. In fact, referring to... Figure 49 As can be seen from the table, good machining quality is achieved in all angle ranges by using condition IR7 and condition IR8 together.

[0267] Furthermore, for example, when the processing direction ND of the first region A1 and the second region A2 is both in the opposite direction ND2 (refer to the second and fourth tables from the top), it can be seen that at the -45° point, in contrast to the example with the forward direction D1, although the quality is reduced when the beam shape of the focusing region C is made into the second shape Q2 (refer to the second table from the top), good quality is obtained when it is made into the first shape Q1 (refer to the fourth table from the top), and good quality can still be obtained at the -40° point.

[0268] Therefore, even if the processing direction ND of regions A1 and A2 is unified to the opposite direction ND2, the beam shape of the focusing region C becomes the second shape Q2 during processing in the angular range from approximately 0° to -40°, and the beam shape of the focusing region C becomes the first shape Q1 during processing in the angular range from approximately -40° to -90°, good processing quality can be obtained in all angular ranges. In fact, referring to... Figure 50 As can be seen from the table, good machining quality is achieved in all angle ranges by using condition IR9 and condition IR10 together.

[0269] That is, given that the laser L is tilted in the direction of the long side NH of the focusing region C, with respect to the processing direction ND, towards the direction with the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the processing direction ND, and when the processing directions of the first region A1 (the first processing mentioned above) and the second region A2 (the second processing mentioned above) are the same in both directions, the boundary between the first region A1 and the second region A2 is set such that the tilt of the long side NH relative to the processing direction ND is a point that contains 45° (in the example above, a point of -45°) on the side that is the same as the side extending obliquely to the crack 13F. Good processing quality can be obtained in all angle ranges.

[0270] The laser processing in this embodiment is based on the above insights. That is, in the laser processing of this embodiment, such as... Figure 48 As shown, the boundary Ks between region A1 and region A2 is set such that the tilt of the long side direction NH is such that it contains a 45° angle with respect to the side on which the oblique crack 13F extends (in the example above, it is a -45° point). In the illustrated example, the boundary Ks is set such that the machining direction ND is the forward direction ND1, and the boundary Ks contains a 45° angle with respect to region A2.

[0271] In particular, compared to the first embodiment, the first region A1 is reduced by about 5° to become an arc of about 40° ranging from 0° to 40°, and the second region A2 is expanded by about 5° to become an arc of about 50° ranging from 40° to 90°. Therefore, the second region A2 is about 10° longer than the first region A1. The processing of the first region A1 and the second region A2 is carried out in the same manner as the first processing and the second processing (and even the first formation and the second formation) described above, except that the processing direction ND is uniformly set to the forward direction ND1 (or the reverse direction ND2).

[0272] The laser processing described in this embodiment will be explained using the structure of the laser processing apparatus 1. Specifically, the laser processing apparatus 1 is an apparatus for irradiating a workpiece 11 with lasers L (lasers L1, L2) to form a modified region 12. It includes at least: a stage 2 for supporting the workpiece 11; an irradiation unit 3 for irradiating the workpiece 11 supported by the stage 2 with the laser L; moving units 4 and 5 for moving the focusing regions C (focusing regions C1, C2) of the laser L relative to the workpiece 11; and a control unit 6 for controlling the moving units 4 and 5 and the irradiation unit 3. The irradiation unit 3 has a spatial light modulator 7, which shapes the laser L so that the focusing region C, when viewed from the Z direction, has a long side direction NH.

[0273] Furthermore, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 to perform the first processing (the first processing described above), thereby causing the focusing area C (focusing area C1, C2) to move relative to the first area A1 in line A, thereby forming a modified area 12 (modified area 12a, 12b) on the object 11 along the first area A1, and forming oblique cracks 13F (cracks 13a, 13b) extending obliquely in the Z direction from the modified area 12 toward the second surface 11b opposite to the incident surface of the object 11, i.e., the first surface 11a.

[0274] Furthermore, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 to perform the second processing (the second processing mentioned above), thereby causing the focusing area C (focusing area C1, C2) to move relative to the second area A2 in line A, thereby forming a modified area 12 (modified area 12a, 12b) on the object 11 along the second area A2, and forming oblique cracks 13F (cracks 13a, 13b) extending from the modified area 12 toward the second surface 11b.

[0275] In the first and second processing steps, the control unit 6 controls the spatial light modulator 7 to shape the laser L such that, for the processing travel direction ND, the long side direction NH of the focusing region C is tilted toward the direction with the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the moving direction of the focusing region C, i.e., the processing travel direction ND, and the clockwise and counterclockwise directions of the processing travel direction ND of the first and second processing steps are the same.

[0276] Furthermore, when the point where the second crystal orientation K2 intersects line A is 0°, the point where the first crystal orientation K1 intersects line A is 90°, and the point between 0° and 90° of line A is 45°, the boundary Ks of the first region A1 and the second region A2, when viewed from the Z direction, is set such that the tilt of the long side direction NH relative to the processing direction ND is a point containing 45° on the side that is the same as the side extending obliquely to the crack 13F.

[0277] Next, regarding the laser processing of this embodiment described above, the process steps of the laser processing method will be explained. That is, the laser processing method of this embodiment is a method for forming a modified region 12 by irradiating a workpiece 11 with lasers L (lasers L1, L2), and has a first processing step (the first processing described above), in which a focusing region C (focusing region C1, C2) is moved relative to the workpiece 11 along a first region A1 set in a line A, thereby forming a modified region 12 (modified region 12a, 12b) on the workpiece 11 along the first region A1, and forming oblique cracks 13F (cracks 13a, 13b) extending obliquely in the Z direction from the modified region 12 toward a second surface 11b opposite to the incident surface of the workpiece 11, i.e., the first surface 11a.

[0278] Furthermore, the laser processing method of this embodiment has a second processing step (the second processing described above), which involves moving the focusing region C (focusing regions C1, C2) relative to the second region A2 in line A, thereby forming a modified region 12 (modified regions 12a, 12b) on the object 11 along the second region A2, and forming oblique cracks 13F (cracks 13a, 13b) extending from the modified region 12 toward the second surface 11b.

[0279] In the first and second processing steps, the laser L is shaped such that, when viewed from the Z direction, the focusing region C has a long side direction NH, and for the processing travel direction ND, the long side direction NH of the focusing region C is tilted toward the direction with the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the moving direction of the focusing region C, i.e., the processing travel direction ND, and the clockwise and counterclockwise directions of the processing travel direction ND in the first and second processing steps are the same.

[0280] Furthermore, when the point where the second crystal orientation K2 intersects line A is 0°, the point where the first crystal orientation K1 intersects line A is 90°, and the point between 0° and 90° of line A is 45°, the boundary Ks of the first region A1 and the second region A2, when viewed from the Z direction, is set such that the tilt of the long side direction NH relative to the processing direction ND is a point containing 45° on the side that is the same as the side extending obliquely to the crack 13F.

[0281] As explained above, in the laser processing apparatus 1 and laser processing method of this embodiment, the object 11 has a crystalline structure comprising: a (100) surface, one (110) surface, another (110) surface, a first crystal orientation K1 orthogonal to one (110) surface, and a second crystal orientation K2 orthogonal to the other (110) surface. Furthermore, in both cases where a modified region 12 is formed on the object 11 along the first region A1 in line A that moves the focusing region C of the laser L (first processing, first processing step), and in cases where a modified region 12 is formed on the object 11 along the second region A2 in line A (second processing, second processing step), the laser L is shaped such that the long side direction NH of the focusing region C is inclined relative to the processing travel direction ND, towards the direction with the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the processing travel direction ND. Therefore, as explained above, the reduction in the quality of the trimmed surface is suppressed.

[0282] On the other hand, in the laser processing apparatus 1 and laser processing method of this embodiment, the first processing and the second processing (the first processing step and the second processing step are also the same (hereinafter the same)) form an oblique crack 13F that extends obliquely from the modified region 12 toward the second surface 11b (opposite surface) opposite to the first surface 11a (incident surface) of the object 11 in the Z direction (the direction intersecting the incident surface). Therefore, it is necessary to consider the relationship between the direction of extension of the oblique crack 13F and the orientation of the long side direction NH of the focusing region C. In particular, when processing at a point of 45°, when the orientation of the long side direction NH of the focusing region C and the tilt direction of the oblique crack 13F are opposite to each other with respect to the processing travel direction ND, the quality of the trimmed surface is easily reduced.

[0283] In this respect, in the laser processing apparatus 1 and laser processing method of this embodiment, the boundary Ks between the first region A1 and the second region A2 is set such that the tilting direction of the long side direction NH in the first region A1 and the second region A2 is such that it contains a 45° angle with respect to the processing travel direction ND on the side that is the same as the side from which the oblique crack 13F extends. In other words, in the first region A1 and the second region A2, the regions processed in which the tilting direction of the long side direction NH of the focusing region C and the oblique crack 13F are opposite to each other with respect to the processing travel direction ND will not reach the 45° point of line A. Thus, quality degradation can be suppressed. As described above, according to the laser processing apparatus 1 and laser processing method of this embodiment, the oblique crack 13F can be formed while suppressing quality degradation of the surface to be finished on the object 11.

[0284] Furthermore, in the laser processing apparatus 1 and laser processing method of this embodiment, the forward and reverse directions of the processing travel direction ND of the first processing process and the second processing process are the same. Therefore, compared with the case where the forward and reverse directions of the processing travel direction ND are switched between the first processing process and the second processing process, the time required for acceleration and deceleration of the relative movement of the focusing area C of the laser L can be reduced.

[0285] Alternatively, in the laser processing apparatus 1 of this embodiment, when viewed from the Z direction, the side of the inclined direction NH of the first region A1 and the second region A2 is longer than the side of the same direction as the side extending obliquely to the crack 13F in the processing travel direction ND. As described above, the lengths of the first region A1 and the second region A2 can also be set individually.

[0286] Alternatively, in the laser processing apparatus 1 of this embodiment, the control unit 6 may perform the first and second processing processes for the first part 15A while keeping the forward and reverse directions of the processing travel direction ND the same, and perform other processing processes (other processing) different from the first and second processing processes for the second part 15B. In other processing processes, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 to keep the forward and reverse directions of the processing travel direction ND the same throughout the entire line A and to move the focusing area C relative to each other along the line A, thereby forming a modified area 12 and a crack 13 extending from the modified area 12 along the Z direction on the object 11 along the line A. In this case, compared to the case where the forward and reverse directions of the processing travel direction ND are switched between the first area A1 and the second area A2 of the line A for the second part 15B, the time required for acceleration and deceleration of the relative movement of the focusing area C of the laser L can be reduced.

[0287] Alternatively, the laser processing apparatus 1 of this embodiment may also involve the control unit 6 controlling the spatial light modulator 7 during other processing steps, thereby shaping the laser L such that, when viewed from the Z direction, the focusing region C has a long side direction NH, and the long side direction NH of the focusing region C is along the processing travel direction ND. In this case, compared to the case where the laser L is shaped by varying the processing of the first region A1 and the second region A2 along the line A, with the second portion 15B having a crack 13 formed along the Z direction, the processing of the control unit 6 is simplified.

[0288] Alternatively, in the laser processing apparatus 1 of this embodiment, the second part 15B may not be switched in the processing direction ND as another processing process. Instead, the first Z processing and the second Z processing are performed as different processing processes. In the first Z processing (the first Z processing mentioned above), the irradiation unit 3 and the moving units 4 and 5 are controlled to move the focusing area C relative to each other along the first region A1 in line A, thereby forming a modified region 12 on the object 11 along the first region A1 and forming a crack 13 extending from the modified region 12 along the Z direction. In the second Z processing (the second processing mentioned above), the irradiation unit 3 and the moving units 4 and 5 are controlled to move the focusing area C relative to each other along the second region A2 in line A, thereby forming a modified region 12 on the object 11 along the second region A2 and forming a crack 13 extending from the modified region 12 along the Z direction. In this case, also for part 2, 15B, compared to the case where the long side direction NH of the focusing region C is set in the first region A1 and the second region A2 according to the processing travel direction ND, and the clockwise and counterclockwise processing travel direction ND is switched in the first region A1 and the second region A2, the time required for acceleration and deceleration of the relative movement of the focusing region C of the laser L can be reduced.

[0289] Alternatively, in the laser processing apparatus 1 of this embodiment, the object 11 may have a joining region that joins with other components (object 11R). In the first and second processing steps, the control unit 6 forms an oblique crack 13F that slopes from the inner side of the joining region toward the outer edge 11e of the joining region as it moves from the first surface 11a toward the second surface 11b. In this case, when a portion of the object 11 bounded by the oblique crack 13F is removed from the object 11, leaving a residual portion of the object 11, it is possible to prevent the object 11 from extending outward across the joining region with other components.

[0290] Furthermore, in the laser processing apparatus 1 of this embodiment, the control unit 6 can perform a first forming process and a second forming process in the first processing and the second processing. In the first forming process (the first forming mentioned above), the position of the focusing region C1 is set at the first Z position Z1 in the Z direction, and the focusing region C1 is moved relative to the object 11 along line A, thereby forming the modified region 12a and the crack 13a extending from the modified region 12a. In the second forming process (the second forming mentioned above), the position of the focusing region C2 is set at the second Z position Z2 in the Z direction, which is closer to the first surface 11a than the first Z position Z1, and the focusing region C2 is moved relative to the object 11 along line A, thereby forming the modified region 12b and the crack 13b extending from the modified region 12b.

[0291] In the first forming process, the control unit 6 sets the position of the focusing region C1 in the Y direction, which intersects the processing travel directions ND and Z, as the first Y position Y1. In the second forming process, the control unit 6 sets the position of the focusing region C2 in the Y direction to the second Y position Y2, which is shifted from the first Y position Y1. Under the control of the spatial light modulator 7, the laser L2 is shaped such that the shape of the focusing region C2 within the YZ plane S, which includes both the Y and Z directions, becomes an inclined shape that is at least tilted towards the shift direction from the first plane 11a further than the center of the focusing region C2. This forms a diagonal crack 13F tilted towards the shift direction within the YZ plane S. In this way, a diagonal crack tilted towards the Z direction can be appropriately formed.

[0292] Alternatively, in the laser processing apparatus 1 of this embodiment, the irradiation unit 3 may include a focusing lens 33 for focusing the laser L from the spatial light modulator 7 toward the object 11. In the second forming process, the control unit 6 modulates the laser L to an inclined shape by controlling a modulation pattern displayed on the spatial light modulator 7, thereby forming the laser L. In this case, the spatial light modulator 7 can be used to easily form the laser L.

[0293] In this embodiment, the laser processing apparatus 1 may also be configured to modulate a pattern containing a coma pattern for imparting coma aberration to the laser L. During the second forming process, the control unit 6 controls the magnitude of the coma aberration in the coma pattern, thereby performing first pattern control to make the shape of the focusing region C tilted. According to the inventors, in this case, the shape of the focusing region C within the YZ plane S is arc-shaped. That is, in this case, the shape of the focusing region C is tilted in the lateral displacement direction closer to the first surface 11a (incident surface) than the center Ca of the focusing region C, and tilted in the lateral direction opposite to the displacement direction, further away from the incident surface than the center Ca of the focusing region C. Even in this case, a diagonal crack 13F tilted in the displacement direction may be formed.

[0294] Alternatively, the laser processing apparatus 1 in this embodiment may also include a modulation pattern containing a spherical aberration correction pattern for correcting the spherical aberration of the laser L. In the second formation process, the control unit 6 performs a second pattern control, which shifts the center of the spherical aberration correction pattern Ps in the Y direction relative to the center of the entrance pupil surface 33a of the condenser lens 33, thereby making the shape of the focusing region C tilted. According to the inventors' understanding, in this case, similar to the case using a coma aberration pattern, the shape of the focusing region C can be formed into an arc shape in the YZ plane S, and a slanted crack 13F tilted in the displacement direction can be formed.

[0295] Alternatively, in the laser processing apparatus 1 of this embodiment, during the second forming process, the control unit 6 performs a third pattern control, which displays an asymmetrical modulation pattern on the spatial light modulator 7 along the axis of the processing travel direction ND, thereby making the shape of the focusing region C tilted. According to the inventors' understanding, in this case, the entire shape of the focusing region C within the YZ plane S can be tilted in the displacement direction. Even in this case, a diagonal crack 13F tilted in the displacement direction can be formed.

[0296] Alternatively, the laser processing apparatus 1 in this embodiment may also have a modulation pattern containing an elliptical pattern. This pattern defines the shape of the focusing region C within the XY plane, which intersects the Y and Z directions, as an ellipse with the X direction as its longer side. In the second forming process, the control unit 6 displays the modulation pattern on the spatial light modulator 7 in a manner where the intensity of the elliptical pattern is asymmetrical about the axis along the X direction, thereby performing a fourth pattern control to make the beam shape tilted. According to the inventors' understanding, in this case, the shape of the focusing region C can also be formed into an arc shape within the YZ plane S, and a diagonal crack 13F tilted in the displacement direction can be formed.

[0297] Alternatively, in the laser processing apparatus 1 of this embodiment, during the second forming process, the control unit 6 displays a modulation pattern for forming focusing points CI of multiple lasers L arranged along the shifting direction in the YZ plane S on the spatial light modulator 7, thereby performing a fifth pattern control to make the shape of the focusing region C containing the multiple focusing points CI tilted. According to the inventors' understanding, in this case, a diagonal crack 13F tilted in the shifting direction can also be formed.

[0298] [Variation Example]

[0299] The above description addresses one aspect of the laser processing apparatus and method, but this disclosure is not limited to the above-described aspect and may include variations.

[0300] For example, in the above example, although an object 100 (bonded wafer) is formed by bonding object 11 with object 11R, the object processed by laser is not limited to such a bonded wafer, and may also be an object such as a single wafer.

[0301] In addition, Figure 45The example shown illustrates the case where, for part 15A, two focusing regions C1 and C2 are used to form two modified regions 12a and 12b. In this case, when forming the oblique crack 13F, the beam shape within the YZ plane S of the focusing region C2 on the side closest to the first surface 11a is controlled at least. However, for part 15A, when multiple sets of modified regions 12a and 12b are formed, when forming the modified regions 12a and 12b closest to the second surface 11b (object 11R side), the beam shape within the YZ plane S of the focusing region C2 on the side closest to the first surface 11a is only required to be controlled at least.

[0302] Furthermore, in the above embodiment, a vertical crack is formed in the second part 15B of the object 11. However, a diagonal crack may also be formed in the second part 15B of the object 11, similar to the first part 15A.

[0303] Furthermore, in the laser processing of the first embodiment, it is described that the processing of the first region A1 (first processing) and the processing of the second region A2 (second processing) in line A are set on the GUI in a manner that switches at 45° intervals, such as 0°, 45°, and 90°, and the actual ON and OFF of the laser are also performed at the same angle. However, in actual devices, due to the delay of the laser ON and OFF, there may be cases where it is several hundred milliseconds slower than set. That is, it is not limited to performing the laser ON and OFF strictly at the boundary between the first region A1 and the second region A2.

[0304] Furthermore, for the reasons stated above, in order to reduce the positional error of the modified region 12, the control unit 6 can also pre-correct the ON and OFF delay times of the laser, and thus has correction parameters to enable the laser to ON and OFF earlier. In this case, the positional error of the modified region 12 can be suppressed to within 1 mm. As an example, if the object 11 is a 12-inch wafer with a circumference of approximately 942 mm, then each 1° is approximately 2.617 mm, and therefore the error in this case can be reduced to within 1°.

[0305] In addition, such as Figure 38 As the results show, a processing quality margin of approximately ±5° was found at the switching point between region A1 and region A2. Therefore, as long as the switching point is set within a quality margin of 45°±5°, 90°±5°, or 90°±5°, it can be intentionally staggered.

[0306] Furthermore, in the above-described embodiment, the modified region 12, which appears as a ring when viewed from the Z direction, is formed by, for example, switching the laser on and off. Strictly speaking, the modified regions 12 (e.g., about several hundred μm) partially overlap in the ON and OFF positions, or conversely, the modified regions 12 may be present in a portion of the unformed area (e.g., about several hundred μm). To prevent quality deterioration due to these effects, sometimes a multi-segment process is used to form oblique cracks and achieve the effects of the first and second processes described above.

[0307] Furthermore, in actual processing, a run-up distance is required until the relative movement speed of the focusing area C becomes constant. Therefore, the switching between forward ND1 and reverse ND2 includes this run-up. During the run-up, the laser is turned off, and after reaching a constant speed, the laser is turned on at the switching point. The number of revolutions during the run-up depends on the performance of the device. Additionally, regarding autofocus, it can also be adjusted by following the laser during the run-up to prevent overshoot during the formation of the modified area.

[0308] Furthermore, in the second embodiment, the switching precision is the same as in the example above, but the switching points, such as 45° and 135°, are used as follows: Figure 49 As shown in the table, at least at the -45° point, there is no switching; switching is centered around the -50° point (in...). Figure 50 The example table uses a point at -40° as the center for switching. In this case, the allowable displacement is, for example, about ±2°, but due to the beam shape (further increasing the ellipticity), it can be increased to, for example, about ±4°. On the other hand, although there is no need to offset the switching points at 0° and 90°, they can be offset by, for example, within a range of about ±4° to accommodate the quality.

[0309] [Industry availability]

[0310] A laser processing apparatus and a laser processing method are provided that can suppress the quality reduction of the trimmed surface of an object whose outer edge is removed and prevent the formation of oblique cracks.

[0311] Symbol Explanation

[0312] 1…Laser processing device; 2…Stage (support); 3…Irradiation unit; 4, 5…Moving unit; 6…Control unit; 7…Spatial light modulator; 11…Object; 11a…First surface (incident surface); 11b…Second surface (opposite surface); 12, 12a, 12b…Modified area; 13, 13a, 13b…Crack; 13F…Oblique crack; 33…Focusing lens; A1…First region; A2…Second region; K1…First crystallization orientation; K2…Second crystallization orientation; L…Laser; C, C1, C2…Focusing area; ND…Processing direction.

Claims

1. A laser processing apparatus, wherein, It is a laser processing device used to irradiate an object with a laser to form a modified area. have: A support portion, which is used to support the object; An irradiation unit for irradiating the object supported by the support unit with the laser; A moving part for moving the focusing area of ​​the laser relative to the object; and A control unit, which controls the moving part and the irradiation part. The object has a crystalline structure comprising: a (100) facet, a (110) facet, another (110) facet, a first crystalline orientation orthogonal to the one (110) facet, and a second crystalline orientation orthogonal to the other (110) facet. The object is supported on the support portion such that the (100) facet becomes the incident surface of the laser. The object is provided with an annular line that, when viewed from the Z direction intersecting the incident plane, includes a first arc-shaped region and a second arc-shaped region, wherein the second region has a boundary with the first region. The irradiation section includes a shaping section that shapes the laser beam such that, when viewed from the Z direction, the focusing region has a long side direction. The control unit implements: The first processing involves controlling the irradiation unit and the moving unit to move the focusing area relative to each other along the first region in the line, thereby forming the modified region on the object along the first region, and forming oblique cracks extending obliquely relative to the Z direction from the modified region toward the opposite side opposite to the incident surface of the object. as well as The second processing involves controlling the irradiation unit and the moving unit to move the focusing area relative to each other along the second region of the line, thereby forming the modified region on the object along the second region and forming the oblique crack extending from the modified region toward the opposite surface. In the first and second processing steps, the control unit controls the forming unit to shape the laser so that the long side direction of the focusing region is tilted relative to the processing travel direction with the larger angle between the first and second crystallization orientations and the processing travel direction that is the moving direction of the focusing region. Furthermore, by controlling the moving unit, the clockwise and counterclockwise directions of the processing travel direction are made the same in both the first and second processing steps. When the point where the second crystal orientation orthogonal to the line is set to 0°, the point where the first crystal orientation orthogonal to the line is set to 90°, and the point midway between the 0° and 90° of the line is set to 45°, the boundary of the first region and the second region is defined such that, when viewed from the Z direction in the first region and the second region, the tilt of the long side direction relative to the processing direction and the side extending from the oblique crack includes the point at 45°.

2. The laser processing apparatus as described in claim 1, wherein, One of the first region and the second region is longer than the other of the first region and the second region.

3. The laser processing apparatus as described in claim 1, wherein, The object comprises: a first part and a second part arranged sequentially from the opposite side along the Z direction. The control unit, for the first part, sets the forward and reverse directions of the processing travel to be the same and performs the first processing and the second processing, and for the second part, performs other processing different from the first processing and the second processing. In the other processing steps, the control unit controls the irradiation unit and the moving unit to make the forward and reverse directions of the processing travel the same throughout the entire line and to move the focusing area relative to each other along the line, thereby forming the modified area and the crack extending from the modified area along the Z direction on the object along the line.

4. The laser processing apparatus as described in claim 2, wherein, The object comprises: a first part and a second part arranged sequentially from the opposite side along the Z direction. The control unit, for the first part, sets the forward and reverse directions of the processing travel to be the same and performs the first processing and the second processing, and for the second part, performs other processing different from the first processing and the second processing. In the other processing steps, the control unit controls the irradiation unit and the moving unit to make the forward and reverse directions of the processing travel the same throughout the entire line and to move the focusing area relative to each other along the line, thereby forming the modified area and the crack extending from the modified area along the Z direction on the object along the line.

5. The laser processing apparatus as described in claim 3, wherein, In the other processing steps, the control unit controls the forming unit to shape the laser so that the long side direction of the focusing region is along the processing travel direction.

6. The laser processing apparatus as described in claim 4, wherein, In the other processing steps, the control unit controls the forming unit to shape the laser so that the long side direction of the focusing region is along the processing travel direction.

7. The laser processing apparatus as described in claim 1, wherein, The object includes: a joint area that joins with other components. In the first and second processing steps, the control section is formed with an oblique crack that slopes from the inner side of the joint area toward the outer edge of the joint area as it moves from the incident surface toward the opposite surface.

8. The laser processing apparatus as described in claim 2, wherein, The object includes: a joint area that joins with other components. In the first and second processing steps, the control section is formed with an oblique crack that slopes from the inner side of the joint area toward the outer edge of the joint area as it moves from the incident surface toward the opposite surface.

9. The laser processing apparatus as described in claim 3, wherein, The object includes: a joint area that joins with other components. In the first and second processing steps, the control section is formed with an oblique crack that slopes from the inner side of the joint area toward the outer edge of the joint area as it moves from the incident surface toward the opposite surface.

10. The laser processing apparatus as described in claim 4, wherein, The object includes: a joint area that joins with other components. In the first and second processing steps, the control section is formed with an oblique crack that slopes from the inner side of the joint area toward the outer edge of the joint area as it moves from the incident surface toward the opposite surface.

11. The laser processing apparatus as described in claim 5, wherein, The object includes: a joint area that joins with other components. In the first and second processing steps, the control section is formed with an oblique crack that slopes from the inner side of the joint area toward the outer edge of the joint area as it moves from the incident surface toward the opposite surface.

12. The laser processing apparatus as described in claim 6, wherein, The object includes: a joint area that joins with other components. In the first and second processing steps, the control section is formed with an oblique crack that slopes from the inner side of the joint area toward the outer edge of the joint area as it moves from the incident surface toward the opposite surface.

13. The laser processing apparatus according to any one of claims 1 to 12, wherein, In the first and second processing steps, the control unit performs the following: The first forming process sets the position of the light-concentrating region in the Z direction as the first Z position and moves the light-concentrating region relative to each other along the line, thereby forming the first modified region as the modified region and the cracks extending from the first modified region on the object. as well as The second forming process involves setting the position of the focusing region in the Z direction to a second Z position, which is closer to the incident surface than the first Z position, and moving the focusing region relative to the line to form a second modified region as the modified region and cracks extending from the second modified region. In the first forming process, the control unit sets the position of the focusing area in the Y direction, which intersects the processing travel direction and the Z direction, as the first Y position. In the second forming process, the control unit sets the position of the focusing area in the Y direction to a second Y position that has been shifted from the first Y position, and through the control of the forming unit, the laser is formed such that the shape of the focusing area in the YZ plane, which includes the Y direction and the Z direction, becomes an inclined shape that is at least inclined towards the shift direction on the side closer to the incident surface than the center of the focusing area, thereby forming the oblique crack in the YZ plane in an inclined manner towards the shift direction.

14. The laser processing apparatus as described in claim 13, wherein, The forming part includes a spatial light modulator for modulating the laser according to a modulation pattern, thereby forming the laser. The irradiation unit includes a focusing lens for focusing the laser light from the spatial light modulator toward the object. In the second forming process, the control unit modulates the laser in such a way that the shape of the focusing area becomes the tilted shape by controlling the modulation pattern displayed on the spatial light modulator, thereby forming the laser.

15. The laser processing apparatus as described in claim 14, wherein, The modulation pattern includes a coma pattern for imparting coma aberration to the laser. In the second forming process, the control unit controls the magnitude of the coma aberration through the coma aberration pattern, thereby performing a first pattern control to make the shape of the focusing area the tilted shape.

16. The laser processing apparatus as described in claim 14 or 15, wherein, The modulation pattern includes: a spherical aberration correction pattern for correcting the spherical aberration of the laser. In the second forming process, the control unit shifts the center of the spherical aberration correction pattern toward the Y direction relative to the center of the incident pupil surface of the condenser lens, thereby performing a second pattern control to make the shape of the condenser region the tilted shape.

17. The laser processing apparatus as described in claim 14 or 15, wherein, In the second forming process, the control unit displays the modulation pattern, which is asymmetrical with respect to the axis along the processing direction, on the spatial light modulator, thereby performing a third pattern control to make the shape of the focusing area become the tilted shape.

18. The laser processing apparatus as described in claim 14 or 15, wherein, The modulation pattern includes an elliptical pattern, which is used to make the shape of the focusing region in the XY plane, which includes the X direction intersecting the Y direction and the Z direction, an ellipse with the X direction as the long side. In the second forming process, the control unit displays the modulation pattern on the spatial light modulator in such a way that the intensity of the elliptical pattern is asymmetrical with respect to the axis along the X direction, thereby performing a fourth pattern control to make the shape of the focusing area become the tilted shape.

19. The laser processing apparatus as described in claim 14 or 15, wherein, In the second forming process, the control unit displays the modulation pattern for forming a plurality of laser focusing points arranged along the shifting direction in the YZ plane on the spatial light modulator, thereby performing a fifth pattern control for making the shape of the focusing region containing the plurality of focusing points the tilted shape.

20. A laser processing method, wherein, It is a laser processing method used to irradiate an object with a laser to form a modified region. have: In the first processing step, the focusing area of ​​the laser is moved relative to the first region along the line set in the object, thereby forming the modified region on the object along the first region, and forming an oblique crack extending obliquely in the Z direction relative to the incident surface of the laser on the object from the modified region toward the opposite side. as well as The second processing step involves moving the focusing area relative to the object along a second region of the line, thereby forming the modified region along the second region and forming the oblique crack extending from the modified region toward the opposite surface. The object has a crystalline structure comprising: a (100) facet, a (110) facet, another (110) facet, a first crystalline orientation orthogonal to the one (110) facet, and a second crystalline orientation orthogonal to the other (110) facet, wherein the (100) facet is designated as the incident facet. The object is provided with an annular line that, when viewed from the Z direction, includes a first arc-shaped region and a second arc-shaped region, wherein the second region has a boundary with the first region. In the first processing step and the second processing step, The laser shaping is configured such that, when viewed from the Z direction, the focusing region has a long side direction, and the long side direction of the focusing region is inclined relative to the processing travel direction with the larger angle between the first crystallization orientation and the second crystallization orientation and the processing travel direction which is the moving direction of the focusing region, and the clockwise and counterclockwise directions of the processing travel direction are made the same in the first processing step and the second processing step. When the point where the second crystal orientation orthogonal to the line is set to 0°, the point where the first crystal orientation orthogonal to the line is set to 90°, and the point midway between the 0° and 90° of the line is set to 45°, the boundary of the first region and the second region is defined such that, when viewed from the Z direction in the first region and the second region, the tilt of the long side direction relative to the processing direction and the side extending from the oblique crack includes the point at 45°.

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