TW202205400A - Laser processing device and laser processing method - Google Patents

Abstract

Provided is a laser processing device for irradiating a subject with laser light to form a reformed area, the laser processing device being provided with: a support unit for supporting the subject; an irradiation unit for irradiating the subject supported by the support unit with the laser light; a movement unit for moving a light collection area of the laser light relatively to the subject; and a control unit for controlling the movement unit and the irradiation unit. The subject has a crystalline structure including a (100) plane, one (110) plane, a different (110) plane, and a first crystal orientation orthogonal to the one (110) plane, and a second crystal orientation orthogonal to the different (110) plane. The (100) plane is supported by the support unit so as to be an incident plane of the laser light. For the subject, a line having an annular shape when viewed in a Z direction intersecting with the incident surface is set.

Description

Laser processing device and laser processing method

One aspect of the present invention relates to a laser processing apparatus and a laser processing method.

The laser processing apparatus described in Patent Document 1 includes a holding mechanism for holding a workpiece, and a laser irradiation mechanism for irradiating a workpiece held by the holding mechanism with laser light. In the laser processing apparatus described in Patent Document 1, a laser irradiation mechanism having a condenser lens is fixed to a base, and the workpiece is moved in a direction perpendicular to the optical axis of the condenser lens by a holding mechanism. move. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5456510 [Patent Document 2] Japanese Patent Application Laid-Open No. 2020-069530

[Problems to be Solved by Invention]

However, in processes such as semiconductor devices, there are cases where trimming is performed. In this trimming process, the outer edge portion of the semiconductor wafer is removed as an unnecessary portion. However, in order to remove the outer edge portion of the object from the object, the laser beam is formed along the line by relatively moving the condensing point of the laser light along the line extending annularly inside the outer edge of the object. In the modified region, it is known that the quality of the trimmed surface of the object formed by removing the outer edge portion may decrease depending on the location.

On the other hand, according to the knowledge of the present inventors, during the trimming process, the cracks are extended from the modified region so as to reach the surface on the opposite side from the incident surface side of the laser light of the object, not along the In order to extend the crack in the vertical direction with respect to the thickness direction of the object, it is required to extend the crack obliquely with respect to the thickness direction. This is to suppress, for example, a phenomenon in which, when a crack is extended in the thickness direction, it will reach another object (for example, on a wafer that is an object) arranged directly below the object in the thickness direction. bonded other wafers). That is, the inventors of the present invention have new knowledge in the above-mentioned technical field, that is, it is required that the oblique cracks can be formed in a state in which the quality degradation of the trimmed surface of the object after the outer edge portion is removed is suppressed.

Then, one aspect of the present invention aims to provide a laser processing apparatus and a laser processing method capable of forming an oblique crack while suppressing deterioration in the quality of the trimmed surface of the object after removal of the outer edge portion. . [Technical means to solve problems]

The inventors of the present invention have come to the following knowledge as a result of earnest research in order to solve the above-mentioned problems. That is, first, when the object is a wafer, the wafer has the (100) plane as its main plane, and has a first crystal orientation orthogonal to one (110) plane and a first crystal orientation orthogonal to the other (110) plane. In the case of the second crystal orientation, among the first crystal orientation and the second crystal orientation, the angle between the first crystal orientation and the second crystal orientation and the processing progress direction (the direction of relative movement of the light-converging point), whichever is larger, is close to the processing progress. By shaping the beam shape so that the direction is inclined, it is possible to suppress deterioration of the quality of the outer surface (for example, refer to the above-mentioned Patent Document 2).

More specifically, when the crack extending from the modified region is stretched in the first crystal orientation, for example, the beam shape is elongated, and the orientation of the longitudinal direction is not the orientation of the processing progress direction. , but inclines so as to approach the second crystal orientation on the opposite side of the first crystal orientation with respect to the processing progress direction. Therefore, for the crack extension force due to the crystal orientation (crystal axis), the crack extension force due to the long beam shape should be able to counteract the crack extension force, so that the crack can be accurately processed along the direction of progress. Stretch well.

Also, when the crack extending from the modified region is stretched in the second crystal orientation, for example, the beam shape is elongated, and the direction of the longitudinal direction is not the direction of the processing progress direction, but is relatively It inclines so as to approach the first crystal orientation on the opposite side to the second crystal orientation side in the processing progress direction. Therefore, the crack extension force due to the crystal orientation should be counteracted by the beam shape being elongated, so that the cracks can be accurately extended along the machining progress direction. As a result, the quality degradation of the trimmed surface should be suppressed.

On the other hand, as a result of further research based on the above-mentioned knowledge, the present inventors found that even if the direction of the longitudinal direction of the beam shape is set as described above according to the direction of processing progress and the crystal structure, the length of the beam shape varies according to the length of the beam shape. The relationship between the direction of the edge direction and the inclination direction of the oblique crack still has room to further suppress the deterioration of the quality of the trimmed surface. That is, when the direction of the longitudinal direction of the beam shape and the inclination direction of the oblique crack are on the same side with respect to the progressing direction of processing, the quality of the trimmed surface is relatively good. However, when the direction of the longitudinal direction of the beam shape and the inclination direction of the oblique crack are opposite to each other with respect to the progressing direction of processing, the quality of the trimmed surface may be relatively poor.

In particular, let the point at which the line defining the direction of machining progresses orthogonal to the second crystal orientation be 0°, the point at which the line intersecting the first crystal orientation is orthogonal to 90°, and 0° and 90° on the line. When the point in the middle of ˚ is set to 45˚, when processing the point of 45˚, if the direction of the longitudinal direction of the beam shape and the inclination direction of the oblique crack are opposite to each other with respect to the progressing direction of machining , it is easy to reduce the quality of the trimmed surface. One aspect of the present invention was completed based on the above general knowledge.

That is, a laser processing apparatus according to an aspect of the present invention is a laser processing apparatus for irradiating a target object with laser light to form a modified region, and includes a support portion for supporting the target object, a laser processing apparatus for an irradiation part for irradiating laser light toward an object supported by the support part, a moving part for relatively moving a light-converging region of the laser light with respect to the object, and a control part for controlling the moving part and the irradiation part; the object has A crystal structure consisting of a (100) plane, one (110) plane, another (110) plane, a first crystal orientation orthogonal to one (110) plane, and a first crystal orientation orthogonal to the other (110) plane In the second crystal orientation, the object is supported by the support part so that the (100) plane becomes the incident surface of the laser light; when the object is viewed from the Z direction intersecting with the incident plane, a circular line is set, and the line The system includes: an arc-shaped first region, and an arc-shaped second region having a boundary with the first region; The laser light is shaped in the direction of the edge; the control unit executes the first processing and the second processing. By relative movement, a modified region is formed in the object along the first region, and an oblique crack extending obliquely with respect to the Z direction is formed from the modified region toward the opposite surface opposite to the incident surface of the object. ; In the second processing, by controlling the irradiating part and the moving part, the light-converging area is relatively moved along the second area in the line, thereby forming a modified area on the object along the second area, and forming a modified area. Oblique cracks in which the quality region extends toward the opposite surface; in the first processing and the second processing, the control part controls the forming part to make the long-side direction of the light-converging region approach the first crystal orientation and the second crystal Among the orientations, the moving direction of the light-converging area, that is, the direction of the larger angle between the processing progress direction, is inclined with respect to the processing progress direction. The forward and reverse directions of the processing progress direction are the same as in the second processing treatment; when the point where the second crystal orientation and the line are orthogonal is set to 0°, the point where the first crystal orientation and the line are orthogonal is set to 90°, and the point between the line and the line is set to 90°. When the point between 0° and 90° is set to 45°, in the first area and the second area, when viewed from the Z direction, the direction of the inclination of the longitudinal direction is the same as the direction of the machining progress. The boundary between the first area and the second area is set so that the side of the crack extension becomes the same side including the 45° point.

Alternatively, a laser processing method according to an aspect of the present invention is a laser processing method for irradiating a target object with laser light to form a modified region, comprising a first processing step and a second processing step, and a first processing step. In the processing step, a modified region is formed on the object along the first region by relatively moving the condensing region of the laser light along the first region in the line set on the object, and the modified region is formed from the modified region. An oblique crack extending obliquely with respect to the Z-direction intersecting the incident surface and extending obliquely with respect to the Z direction intersecting the incident surface, the second processing step is performed by the second processing step along the line. The area moves the light-converging area relatively, and along the second area, a modified area is formed in the object, and an oblique crack extending from the modified area to the opposite side is formed; the object has a crystal structure, and the crystal structure includes: (100) plane, one (110) plane, the other (110) plane, a first crystal orientation orthogonal to one (110) plane, and a second crystal orientation orthogonal to the other (110) plane, and ( 100) The plane is set as the incident plane, and the object is set as an annular line when viewed from the Z direction, and the line includes an arc-shaped first area and an arc-shaped area having a boundary with the first area. The second region; in the first processing step and the second processing step, the long-side direction of the light-converging region is made to be close to the first crystal orientation and the second crystal orientation so that the light-converging region has a longitudinal direction when viewed from the Z direction. Among the crystal orientations, the direction of the movement direction of the light-converging region, that is, the direction of the processing progress, whichever is larger, is inclined with respect to the processing progress direction. The forward and reverse directions of the machining progress direction are set to be the same, and the point where the second crystal orientation is perpendicular to the line is set to 0°, the point where the first crystal orientation and the line are orthogonal is set to 90°, and the point between 0° and 90° on the line is set. When the middle point between ˚ is set to 45˚, in the first area and the second area, when viewed from the Z direction, the direction of the inclination of the longitudinal direction with respect to the machining progress direction is the same as the oblique crack extension side. Set the boundary between the 1st area and the 2nd area so that one side of the same side includes a 45° point.

In these apparatuses and methods, the object has a crystal structure including a (100) plane, one (110) plane, another (110) plane, and a first crystal orthogonal to one (110) plane Orientation, the second crystal orientation orthogonal to the other (110) plane. Here, in the case where a modified region is formed in the object along the first region of the line that relatively moves the condensing region of the laser light (first processing, first processing), and when the modified region is formed along the line When the second region in the line is formed as a modified region in the object (second processing, second processing), the longitudinal direction of the light-condensing region is made to be close to the first crystal orientation and the second crystal orientation. The laser beam is shaped so that the direction of the larger angle between the advancing directions is inclined with respect to the processing advancing direction. Therefore, as shown by the above-mentioned knowledge, the quality degradation of the trimmed surface can be suppressed.

On the other hand, in these apparatuses and methods, in the first processing and the second processing (the same is true for the first processing and the second processing (the same applies hereinafter)), a path from the modified region to the object is formed. An oblique crack extending obliquely with respect to the Z direction (direction intersecting with the incident surface) on the opposite surface to the incident surface. Therefore, as indicated by the above knowledge, it is necessary to consider the relationship between the extending direction of the oblique crack and the orientation of the longitudinal direction of the light-converging region. In particular, when the 45° point processing is performed, if the direction of the longitudinal direction of the light-converging region and the inclination direction of the oblique cracks are opposite to each other with respect to the progressing direction of the processing, the quality of the trimmed surface is likely to deteriorate.

In view of this, in these apparatuses and methods, in the first region and the second region, the direction of the inclination of the longitudinal direction with respect to the machining progress direction is one of the same side as the oblique crack extension side, including 45 ˚ point to set the boundary between the 1st area and the 2nd area. In other words, in the first area and the second area, the areas processed in such a state that the direction of the longitudinal direction of the light-converging area and the inclination direction of the oblique cracks are opposite to each other with respect to the progressing direction of the processing do not reach the upper part of the line. 45˚ point. Therefore, quality degradation can be suppressed. As described above, according to these apparatuses and methods, it is possible to form diagonal cracks in a state in which deterioration of the quality of the trimmed surface of the object is suppressed.

In addition, in these apparatuses and methods, in the first processing and the second processing, the forward and reverse directions of the processing progress directions are the same. Therefore, compared to the case where the forward and reverse directions of the machining progress are switched in the first machining process and the second machining process, the time associated with the acceleration and deceleration of the relative movement of the laser light condensing region can be reduced.

In the laser processing apparatus of one aspect of the present invention, one of the first region and the second region may be set longer than the other of the first region and the second region. In this way, the lengths of the first region and the second region can be set to be different.

In the laser processing apparatus according to one aspect of the present invention, the object may include a first part and a second part arranged in order from the opposite surface side along the Z direction, and the control unit may include, for the first part, The forward and reverse directions of the processing progress are set to be the same, and the first processing and the second processing are carried out. For the second part, other processing different from the first processing and the second processing is carried out. In other processing, The control unit controls the irradiation unit and the moving unit, sets the forward and reverse directions of the machining progress direction to be the same for the entire wire, and relatively moves the light-converging area along the wire, thereby forming a modified area on the object along the wire, and from the modified area along the wire. A crack that extends in the Z direction. In this case, in the second portion where the cracks along the Z direction are formed, the entire wire is laser-processed so that the direction of the processing progress direction is the same. Therefore, compared to the case where the forward and reverse directions of the machining progress are switched between the first and second regions where the second part is a line, the time associated with the acceleration and deceleration of the relative movement of the laser light condensing region can be reduced.

In the laser processing apparatus of one aspect of the present invention, in another processing, the control unit may control the shaping unit to shape the laser light so that the longitudinal direction of the light-converging region may be aligned with the processing progress direction. In this case, in the second portion where the cracks along the Z direction are formed, it is not necessary to set the relationship between the longitudinal direction of the light-converging region and the machining progress direction between the machining of the first region of the wire and the machining of the second region. Since the shaping of the laser beam is performed in a different manner, the processing of the control unit can be simplified.

In the laser processing apparatus according to one aspect of the present invention, the object may include a bonding region to be bonded to another member, and in the first processing and the second processing, the control portion may be formed in an opposite direction from the incident surface. An oblique crack that slopes from the inner side of the joint area toward the outer edge of the joint area. In this case, when a part of the object is removed from the object with the oblique crack as a boundary, and the remaining part of the object is left, the object can be prevented from exceeding the junction area between the object and other members and causing the object to be damaged. The rest of it extends outward.

In the laser processing apparatus of one aspect of the present invention, in the first processing and the second processing, the control unit may execute the first forming processing and the second forming processing, and the first forming processing may be performed in the Z direction. The position of the condensing region above is set to the 1Z position, and the light condensing region is relatively moved along the line, thereby forming the first modified region as the modified region and the crack extending from the first modified region. The object, in the second forming process, is formed by setting the position of the light-converging region in the Z direction to the 2Z position on the incident surface side relative to the 1Z position, and relatively moving the light-converging region along the line. In the second modified region of the modified region and the cracks extending from the second modified region, in the first forming process, the control unit sets the position of the light-converging region in the Y direction intersecting the machining progress direction and the Z direction In the second forming process, the control unit sets the position of the light-condensing area in the Y direction to the 2Y position after shifting from the 1Y position, and controls the forming unit to make it in the 1Y position. The shape of the condensing area in the YZ plane including the Y direction and the Z direction is formed so that the laser beam is shaped so as to be inclined in the direction of displacement at least on the incident surface side from the center of the condensing area, thereby forming the laser beam in the YZ. Oblique cracks are formed in the plane so as to be inclined in the displacement direction. In this way, an oblique crack inclined with respect to the Z direction can be appropriately formed.

In one aspect of the present invention, the laser processing apparatus may also be such that the shaping unit includes: a spatial light modulator for modulating the laser light according to the modulation pattern to shape the laser light, and the irradiation unit includes: A condensing lens for condensing the laser light from the spatial light modulator toward the object. In the second forming process, the control unit controls the modulation pattern displayed on the spatial light modulator so that the light-converging area is The laser light is modulated in such a way that the shape becomes an oblique shape, thereby shaping the laser light. In this case, the laser light can be easily shaped using the spatial light modulator.

In the laser processing apparatus of one aspect of the present invention, the modulation pattern may include a coma aberration pattern for imparting coma aberration to the laser light, and in the second forming process, the control unit may control the coma based on the The magnitude of the coma aberration of the morphological aberration pattern is used to perform the first pattern control for making the shape of the light-converging region into an oblique shape. According to the knowledge of the present inventors, in this case, the shape of the light-converging region in the YZ plane is formed in an arc shape. That is, in this case, the shape of the condensing area is inclined toward the displacement direction on the side of the incident surface from the center of the condensing area, and is inclined toward the opposite side of the incident surface from the center of the condensing area. The direction opposite to the displacement direction is inclined. Also in this case, an oblique crack inclined in the displacement direction can be formed.

In the laser processing apparatus of one aspect of the present invention, the modulation pattern may include a spherical aberration correction pattern for correcting spherical aberration of the laser light, and in the second forming process, the control unit may The center of the entrance pupil surface of the lens is offset in the Y direction with the center of the spherical aberration correction pattern, thereby performing the second pattern control for making the shape of the light-converging region into an oblique shape. According to the knowledge of the present inventors, also in this case, as in the case of using the coma aberration pattern, the shape of the light condensing region in the YZ plane can be formed into an arc shape, and the oblique shape inclined in the displacement direction can be formed. to crack.

In the laser processing apparatus of one aspect of the present invention, in the second forming process, the control unit may display on the spatial light modulator an asymmetric modulation pattern with respect to an axis along the processing direction. , to perform the third pattern control for making the shape of the light-converging region into an oblique shape. According to the knowledge of the present inventors, in this case, the shape of the light-converging region in the YZ plane can be made to incline as a whole in the displacement direction. Also in this case, an oblique crack inclined in the displacement direction can be formed.

In the laser processing apparatus of one aspect of the present invention, the modulation pattern may include an ellipse pattern for making the shape of the light-condensing region in the XY plane an ellipse with a long side in the X direction, and the XY plane may include an ellipse pattern. It includes the X direction and the Y direction intersecting the Y direction and the Z direction; in the second forming process, the control unit displays the modulation pattern in such a way that the intensity of the elliptical pattern becomes asymmetrical with respect to the axis along the X direction. The spatial light modulator performs the fourth pattern control for making the shape of the light-converging region into an oblique shape. According to the knowledge of the present inventors, also in this case, the shape of the light-converging region in the YZ plane can be formed in an arc shape, and an oblique crack inclined in the displacement direction can be formed.

In the laser processing apparatus according to an aspect of the present invention, in the second forming process, the control unit may adjust the focus point for forming a plurality of laser beams aligned along the displacement direction in the YZ plane. The variable pattern is displayed on the spatial light modulator, whereby the fifth pattern control for making the shape of the light-converging region including a plurality of light-converging points into an oblique shape is performed. According to the knowledge of the present inventors, also in this case, an oblique crack inclined in the displacement direction can be formed. [Effect of invention]

According to one aspect of the present invention, there are provided a laser processing apparatus and a laser processing method capable of forming an oblique crack while suppressing deterioration in the quality of the trimmed surface of the object after the outer edge portion has been removed.

Hereinafter, an embodiment will be described in detail with reference to the drawings. In addition, in each drawing, the same or corresponding parts are denoted by the same reference numerals, and repeated descriptions may be omitted. In addition, in each drawing, the orthogonal coordinate system defined by the X-axis, the Y-axis, and the Z-axis may be displayed. [Outline of Laser Processing Device and Laser Processing]

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

The stage 2 supports the object 11 by holding, for example, a film attached to the object 11 . The stage 2 can be rotated about an axis parallel to the Z direction as a rotation axis. The stage 2 may be configured to be movable along the X direction and the Y direction. In addition, the X direction and the Y direction are the first horizontal direction and the second horizontal direction intersecting (orthogonal) with each other, and the Z direction is the vertical direction.

The irradiation unit 3 condenses and irradiates the target 11 with the laser light L having penetrability to the target 11 . When the laser light L is condensed inside the object 11 supported by the stage 2, the laser light L is particularly absorbed in the portion corresponding to the condensing region C of the laser light L (for example, the center Ca described later), and the The modified region 12 is formed inside the object 11 . The condensing region C is a region within a predetermined range from the position where the beam intensity of the laser light L becomes the highest, or the position of the center of gravity of the beam intensity, although the details will be described later.

The modified region 12 is a region different in density, refractive index, mechanical strength, and other physical properties from the surrounding non-modified region. As the modified region 12 , for example, a molten processed region, a cracked region, a dielectric breakdown region, a refractive index change region, and the like can be mentioned. The modified region 12 may be formed such that cracks extend from the modified region 12 toward the incident side of the laser light L and the opposite side thereof. Such modified regions 12 and cracks are used for cutting the object 11 , for example.

As an example, when the stage 2 is moved in the X direction and the light-converging region C is relatively moved in the X direction with respect to the object 11, a plurality of modified spots 12s are formed in a row in the X direction. One modified spot 12s is formed by irradiating the laser light L with one pulse. The modified region 12 in one row is a collection of a plurality of modified spots 12s arranged in one row. The adjacent modified spots 12s may be connected to each other or separated from each other depending on the relative movement speed of the light-converging region C with respect to the object 11 and the repetition frequency of the laser light L.

The moving part 4 includes: a first moving part 41 for moving the stage 2 in one of the directions in the plane intersecting (orthogonal) with the Z direction; The second moving part 42 that moves in the other direction. As an example, the first moving part 41 moves the stage 2 in the X direction, and the second moving part 42 moves the stage 2 in the Y direction. Moreover, the moving part 4 rotates the stage 2 about an axis parallel to the Z direction as a rotation axis. The moving part 5 supports the irradiation part 3 . The moving unit 5 moves the irradiation unit 3 along the X direction, the Y direction, and the Z direction. By moving the stage 2 and/or the irradiation unit 3 in a state where the condensing area C of the laser light L is formed, the condensing area C is moved relative to the object 11 . That is, the moving parts 4 and 5 move at least one of the stage 2 and the irradiation part 3 in order to relatively move the condensing region C of the laser light L with respect to the object 11 .

The control unit 6 controls the operations of the stage 2 , the irradiation unit 3 , and the moving units 4 and 5 . The control unit 6 includes a processing unit, a memory unit, and an input receiving unit (not shown). The processing unit is constituted in the form of a computer device including a processor, a memory, a storage device, a communication device, and the like. In the processing section, the processor executes the software (program) loaded into the memory or the like, and controls the reading and writing of data in the memory and the storage device, as well as the communication based on the communication device. The memory unit is, for example, a hard disk or the like, and is used for storing various data. The input receiving part is an interface part that displays various information and receives input of various information from the user. The input receiving unit constitutes a GUI (Graphical User Interface).

FIG. 2 is a schematic diagram showing the configuration of the irradiation section shown in FIG. 1 . The imaginary line A shown in FIG. 2 shows the predetermined laser processing. As shown in FIG. 2 , the irradiation unit 3 includes a light source 31 , a spatial light modulator (molding unit) 7 , a condenser lens 33 , and a 4f lens unit 34 . The light source 31 outputs the laser light L by, for example, a pulse oscillation method. In addition, the irradiation unit 3 may not include the light source 31 , and may be configured to introduce the laser light L from the outside of the irradiation unit 3 . The spatial light modulator 7 modulates the laser light L output from the light source 31 . The condensing lens 33 condenses the laser light L output from the spatial light modulator 7 by the modulation of the spatial light modulator 7 toward the object 11 .

As shown in FIG. 3 , the 4f lens unit 34 includes a pair of lenses 34A and 34B arranged on the optical path of the laser light L from the spatial light modulator 7 toward the condenser lens 33 . The pair of lenses 34A, 34B is a bilateral telecentric optical system in which the modulation surface 7a of the spatial light modulator 7 and the entrance pupil surface (pupil surface) 33a of the condenser lens 33 are in an imaging relationship. Thereby, the image of the laser light L on the modulation surface 7a of the spatial light modulator 7 (the image of the laser light L after being modulated by the spatial light modulator 7) is transferred (imaged) to the condenser lens 33. Entrance pupil face 33a. In addition, Fs in the figure represents the Fourier surface.

As shown in FIG. 4 , the spatial light modulator 7 is a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) spatial light modulator (SLM: Spatial Light Modulator). The spatial light modulator 7 is formed 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 . and constitute.

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 73 a arranged in a matrix along the surface of the semiconductor substrate 71 . Each pixel electrode 73a is formed of, for example, a metal material such as aluminum. A voltage is applied to each pixel electrode 73 a through the driving circuit layer 72 .

The reflection film 74 is, for example, a dielectric multilayer film. The alignment film 75 is provided on the surface of the liquid crystal layer 76 on the reflective film 74 side, and the alignment film 77 is provided on the surface of the liquid crystal layer 76 on the opposite side to the reflective film 74 . The alignment films 75 and 77 are formed of, for example, a polymer material such as polyimide, and are subjected to, for example, a rubbing process on the contact surfaces of the alignment films 75 and 77 with the liquid crystal layer 76 . The alignment films 75 and 77 are for aligning the liquid crystal molecules 76a contained in the liquid crystal layer 76 along a certain direction.

The transparent conductive film 78 is provided on the surface of the transparent substrate 79 on the alignment film 77 side, and faces the pixel electrode layer 73 with the liquid crystal layer 76 and the like interposed therebetween. 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 light L to pass therethrough.

In the spatial light modulator 7 configured as above, when a signal indicating a modulation pattern is input from the control unit 6 to the driving circuit layer 72, the voltage of the signal is applied to each pixel electrode 73a, and the voltage of the signal is applied to each pixel electrode 73a, and An electric field is formed between it and the transparent conductive film 78 . When the electric field is formed, in the liquid crystal layer 76, the alignment direction of the liquid crystal molecules 76a is changed in each region corresponding to each pixel electrode 73a, and the refractive index in each region corresponding to each pixel electrode 73a is changed. This state is a state in which a modulation pattern is displayed on the liquid crystal layer 76 . The modulation pattern is used to modulate the laser light L.

That is, in the state where the liquid crystal layer 76 displays the modulation pattern, when the laser light L transmits from the outside through the transparent substrate 79 and the transparent conductive film 78 and enters the liquid crystal layer 76, is reflected by the reflective film 74, and then passes through the transparent conductive film from the liquid crystal layer 76. When the film 78 and the transparent substrate 79 are emitted to the outside, the laser light L is modulated according to the modulation pattern displayed on the liquid crystal layer 76 . In this way, according to the spatial light modulator 7, by appropriately setting the modulation pattern displayed on the liquid crystal layer 76, the laser light L can be modulated (for example, the intensity, amplitude, phase, polarization, etc. of the laser light L) modulation). The modulation surface 7a shown in FIG. 3 is, for example, a liquid crystal layer 76 .

As described above, the laser light L output from the light source 31 passes through the spatial light modulator 7 and the 4f lens unit 34 and enters the condensing lens 33 , and is condensed in the object 11 by the condensing lens 33 . In the light-converging region C, a modified region 12 and a crack extending from the modified region 12 are formed in the object 11 . Further, the control unit 6 controls the moving units 4 and 5 to relatively move the condensing area C with respect to the object 11 , thereby forming the modified area 12 and cracks along the moving direction of the condensing area C. [Explanation of knowledge about the formation of oblique cracks]

Here, the relative movement direction (processing progress direction) of the condensing region C at this time is referred to as the X direction. Further, the direction intersecting (orthogonal) with the first surface 11 a of the incident surface of the laser beam L of the object 11 is referred to as the Z direction. Also, the direction intersecting (orthogonal) with the X direction and the Z direction is referred to as the Y direction. The X direction and the Y direction are directions along the first surface 11a. The Z direction can also be defined as the optical axis of the condenser lens 33 and the optical axis of the laser light L condensed toward the object 11 through the condenser lens 33 .

As shown in FIG. 5 , in the intersection plane (YZ plane S including the Y direction and the Z direction) intersecting the X direction of the machining progress direction, it is required to follow the line RA inclined with respect to the Z direction and the Y direction (here , a line RA) inclined at a predetermined angle θ with respect to the Y direction forms an oblique crack. The inventor's knowledge of the formation of such an oblique crack will be described while showing a processing example.

Here, the modified regions 12 a and 12 b are formed as the modified regions 12 . Thereby, the crack 13a extending from the modified region 12a and the crack 13b extending from the modified region 12b are connected to form the crack 13 extending obliquely along the line RA. Here, first, as shown in FIG. 6 , the condensing region C1 is formed with the first surface 11 a of the object 11 serving as the incident surface of the laser light L. As shown in FIG. On the other hand, the condensing region C2 is formed on the side of the first surface 11 a with respect to the condensing region C1 , with the first surface 11 a serving as the incident surface of the laser light L. As shown in FIG. At this time, the light condensing area C2 is displaced by a distance Sz in the Z direction with respect to the light condensing area C1, and is displaced by a distance Sy in the Y direction with respect to the light condensing area C1. The distance Sz and the distance Sy correspond to the slope of the line RA as an example.

On the other hand, as shown in FIG. 7 , by using the spatial light modulator 7 to modulate the laser light L, the beam shape in the YZ plane S of the condensing area C (at least the condensing area C2 ) is On the first surface 11a side at least from the center Ca of the light condensing region C, it has an inclined shape inclined in the displacement direction (here, the negative side of the Y direction) with respect to the Z direction. In the example of FIG. 7 , on the side of the first surface 11a from the center Ca, it is inclined to the negative side in the Y direction with respect to the Z direction, and also on the opposite side of the first surface 11a from the center Ca, with respect to the Z direction. The direction is inclined toward the negative side of the Y direction, and has an arc shape. Furthermore, the beam shape of the condensing area C in the YZ plane S refers to the intensity distribution of the laser light L in the condensing area C in the YZ plane S.

In this way, at least two condensing regions C1 and C2 are shifted in the Y direction, and the beam shape of at least the condensing regions C2 (here, both of the condensing regions C1 and C2) is inclined, as shown in FIG. 9 . As shown in (a), a crack 13 extending obliquely can be formed. For example, by controlling the modulation pattern of the spatial light modulator 7, the modified region 12 and the crack 13 can also be formed by branching the laser light L to form the light-condensing regions C1 and C2 at the same time (multi-focus). processing), after the modified region 12a and the crack 13a are formed by the formation of the light-concentrating region C1, the modified region 12b and the crack 13b may be formed by the formation of the light-concentrating region C2 (single pass). pass) processing).

Alternatively, by forming another light condensing region between the light condensing region C1 and the light condensing region C2, as shown in FIG. The modified region 12c is intervened to form longer cracks 13 extending obliquely.

Next, the understanding for making the beam shape in the YZ plane S of the condensing region C into an oblique shape will be described. First, the definition of the condensing region C will be specifically described. Here, the light-converging region C is a region within a predetermined range from the center Ca (for example, a range of ±25 μm from the center Ca in the Z direction). As described above, the center Ca is the position where the intensity of the beam becomes the highest, or the position of the center of gravity of the intensity of the beam. The position of the center of gravity of the beam intensity is the position of the center of gravity of the beam intensity on the optical axis of the laser light L when the modulation based on the modulation pattern is not performed, for example, the modulation pattern is used for branching the laser light L A modulation pattern such as a modulation pattern for shifting the optical axis of the laser light L. The position where the beam intensity becomes the highest or the center of gravity of the beam intensity can be obtained as follows. That is, the object 11 is irradiated with the laser light L in a state where the output of the laser light L is reduced to such an extent that the modified region 12 cannot be formed on the object 11 (lower than the processing threshold). At the same time, the reflected light of the laser light L from the surface (here, the second surface 11 b ) of the object 11 on the opposite side to the incident surface of the laser light L is, for example, a complex number in the Z direction shown in FIG. 15 . Each position F1~F7 is recorded with the camera. Thereby, the position or the center of gravity where the beam intensity becomes the highest can be obtained from the obtained image. The re-modified region 12 is formed in the vicinity of the center Ca.

In order to make the beam shape in the condensing region C an oblique shape, a method of offsetting the modulation pattern can be used. More specifically, the spatial light modulator 7 displays: a distortion correction pattern for correcting wavefront distortion, a grating pattern for dividing the laser light, a slit pattern, an astigmatism pattern, and a coma pattern. , and various patterns such as a spherical aberration correction pattern (the pattern in which they are superimposed is displayed). However, as shown in FIG. 8 , by offsetting the spherical aberration correction pattern Ps, the beam shape of the condensing region C can be adjusted.

In the example of FIG. 8, on the modulation surface 7a, the center Pc of the spherical aberration correction pattern Ps is offset by the offset amount Oy1 to the negative side in the Y direction with respect to the center Lc of the laser light L (the beam spot). set. As described above, the image of the modulating surface 7 a is transferred to the entrance pupil surface 33 a of the condenser lens 33 by the 4 f lens unit 34 . Therefore, the offset on the modulation surface 7a becomes the offset toward the positive side in the Y direction on the entrance pupil surface 33 . That is, on the entrance pupil surface 33a, the center Pc of the spherical aberration correction pattern Ps is oriented in the Y direction with respect to the center Lc of the laser beam L and the center of the entrance pupil surface 33a (here, it coincides with the center Lc). The positive side is offset by the offset amount Oy2.

In this way, by offsetting the spherical aberration correction pattern Ps, the beam shape of the condensing region C of the laser light L is deformed into an arc-like inclined shape as shown in FIG. 7 . As described above, offsetting the spherical aberration correction pattern Ps is equivalent to imparting coma aberration to the laser beam L. FIG. Therefore, by making the modulation pattern of the spatial light modulator 7 include a coma aberration pattern for imparting coma aberration to the laser light L, the beam shape of the condensing region C can be inclined. Also available as a coma aberration pattern: a pattern corresponding to the first nine terms of the Zernike polynomial (the Y component of the third-order coma aberration), that is, a pattern that generates coma aberration in the Y direction.

Next, the understanding of the relationship between the crystallinity of the object 11 and the cracks 13 will be described. Fig. 10 is a schematic plan view of an object. Here, the object 11 is a silicon wafer (t 775 μm, <100>, 1Ω·cm), and the notch 11d is formed. For the object 11, the first processing example in which the processing progress direction, that is, the X direction is aligned with the 0° (110) plane, is shown in Fig. 11(a), and the second processing example in which the X direction is aligned with the 15° plane is shown in Fig. 11(a). 11(b), the other processing example in which the X direction is aligned with 30° is shown in Fig. 12(a), and the fourth processing example in which the X direction is aligned with the 45° (100) plane is shown in Fig. 12(b). In each processing example, the angle θ of the line RA in the YZ plane S with respect to the Y direction is 71°.

In each processing example, a single pass is used, and the first pass is to relatively move the light-converging region C1 in the X direction to form the modified region 12a and the crack 13a, and the second pass is to let the light-converging region C1 move relatively. C2 relatively moves in the X direction to form the modified region 12b and the crack 13b. The processing conditions of the first pass and the second pass are as follows. In addition, the following CP represents the intensity of condensing correction, and the coma aberration (LBA offset Y) represents the offset amount in the Y direction of the spherical aberration correction pattern Ps in pixel units of the spatial light modulator 7 .

＜1st pass＞ Z-direction position: 161μm CP:-18 Output: 2W Speed: 530mm/s Frequency: 80kHz Comatic Aberration (LBA Bias Y): -5 Y direction position: 0

＜Second pass＞ Z-direction position: 151μm CP:-18 Output: 2W Speed: 530mm/s Frequency 80kHz Comatic Aberration (LBA Bias Y): -5 Y direction position: 0.014mm

As shown in FIGS. 11 and 12 , in either case, the crack 13 can be formed along the line RA inclined at 71° with respect to the Y direction. That is, it is not affected by the (110) plane, the (111) plane, and the (100) plane, which are the main cleavage planes of the object 11, that is, regardless of the crystal structure of the object 11, it can be formed along the The desired line RA is a crack 13 extending diagonally.

Furthermore, the control of the beam shape for forming the fissures 13 extending in such an oblique direction is not limited to the above-mentioned example. Next, another example for making the beam shape into an oblique shape will be described. As shown in FIG. 13( a ), the laser beam L can also be modulated by a modulation pattern PG1 that is asymmetric with respect to the axis Ax along the X-direction of the processing progress direction, so that the beam shape of the condensing region C becomes Sloped shape. The modulation pattern PG1 includes a grid pattern Ga on the negative side in the Y direction relative to the axis Ax, and includes a non-modulation region Ba on the positive side in the Y direction relative to the axis Ax, which passes through the Y direction. The center Lc of the beam spot of the laser light L is along the X direction. In other words, the modulation pattern PG1 includes the grating pattern Ga only on the positive side in the Y direction with respect to the axis Ax. FIG. 13( b ) is obtained by inverting the modulation pattern PG1 of FIG. 13( a ) so as to correspond to the entrance pupil surface 33 a of the condenser lens 33 .

FIG. 14( a ) shows the intensity distribution of the laser light L at the entrance pupil surface 33 a of the condenser lens 33 . As shown in FIG. 14( a ), by using such a modulation pattern PG1 , the portion of the laser light L incident on the spatial light modulator 7 modulated by the grating pattern Ga does not move toward the spatial light modulator 7 . The entrance pupil surface 33a of the condenser lens 33 is incident thereon. As a result, as shown in FIGS. 14( b ) and 15 , the beam shape of the condensing region C in the YZ plane S can be made to have an inclined shape in which the whole is inclined in one direction with respect to the Z direction.

That is, in this case, the beam shape of the condensing region C is inclined to the negative side of the Y direction with respect to the Z direction on the side of the first surface 11a with respect to the center Ca of the condensing region C, and is more than the light condensing region C. The center Ca of C is inclined toward the positive side of the Y direction with respect to the Z direction, which is on the opposite side of the first surface 11a. 15(b) shows the intensity distribution in the XY plane of the laser light L at each position F1 to F7 in the Z direction shown in FIG. 15(a), based on the actual observation results of the camera. Also in the case where the beam shape of the condensing region C is controlled in this way, the cracks 13 extending obliquely can be formed in the same manner as in the above-described example.

Furthermore, the modulation patterns PG2 , PG3 , and PG4 shown in FIG. 16 can also be used as modulation patterns that are asymmetric about the axis Ax. The modulation pattern PG2 includes the non-modulation region Ba and the grid pattern Ga arranged in sequence along the direction away from the axis Ax on the negative side of the Y direction relative to the axis Ax, and is closer to the Y direction than the axis Ax The positive side of the direction contains the non-modulation area Ba. That is, the modulation pattern PG2 includes the grating pattern Ga in a part of the region on the negative side in the Y direction with respect to the axis Ax.

The modulation pattern PG3 includes, on the negative side of the Y direction relative to the axis AX, a non-modulation region Ba and a grid pattern Ga arranged in sequence along the direction away from the axis Ax, and is closer to the Y direction than the axis Ax. The positive side of the direction includes: the non-modulation area Ba and the grid pattern Ga arranged in order along the direction away from the axis Ax. In the modulation pattern PG3, the ratios of the non-modulation area Ba and the grid pattern Ga are different on the positive side in the Y direction and on the negative side in the Y direction than the axis Ax (on the negative side in the Y direction, relatively The non-modulation region Ba is narrowed) to become asymmetrical with respect to the axis Ax.

Like the modulation pattern PG2, the modulation pattern PG4 includes the grating pattern Ga in a part of the region on the negative side in the Y direction with respect to the axis Ax. In the modulation pattern PG4, also in the X direction, the region where the grid pattern Ga is provided becomes a part. That is, in the modulation pattern PG4, the region on the negative side of the Y direction with respect to the axis Ax includes the non-modulated region Ba, the grating pattern Ga, and the non-modulated region Ba arranged in order along the X direction. Here, the grating pattern Ga is arranged in a region including an axis Ay that passes through the center Lc of the beam spot of the laser light L in the X direction and is along the Y direction.

Using any of the above modulation patterns PG2 to PG4, the beam shape of the condensing region C can be made to have an inclined shape inclined toward the negative side of the Y direction with respect to the Z direction at least on the first surface 11a side with respect to the center Ca. That is, in order to control the beam shape of the condensing region C so as to be inclined toward the negative side of the Y direction with respect to the Z direction at least on the first surface 11a side from the center Ca, the modulation patterns PG1 to PG4 including modulation patterns PG1 to PG4 can be used. An asymmetric modulation pattern of the grid pattern Ga, or an asymmetric modulation pattern of the grid pattern Ga other than the modulation patterns PG1 to PG4.

In addition, the grid pattern Ga is not limited to be used as an asymmetric modulation pattern for making the beam shape of the condensing region C into an oblique shape. FIG. 17 shows another example of asymmetric modulation patterns. As shown in FIG. 17( a ), the modulation pattern PE includes an elliptical pattern Ew on the negative side in the Y direction relative to the axis Ax, and includes an elliptical pattern Es on the positive side in the Y direction relative to the axis Ax. FIG. 17( b ) is obtained by inverting the modulation pattern PE of FIG. 17( a ) so as to correspond to the entrance pupil surface 33 a of the condenser lens 33 .

As shown in FIG. 17( c ), the elliptical patterns Ew and Es are both for making the beam shape in the light-condensing region C of the XY plane including the X-direction and the Y-direction an elliptical shape with the X-direction as the longitudinal direction picture of. However, in the elliptical pattern Ew and the elliptical pattern Es, the intensity of modulation is different. More specifically, the modulation intensity of the elliptical pattern Es is greater than the modulation intensity of the elliptical pattern Ew. That is, the light-converging region Cs formed by the laser light L modulated by the elliptical pattern Es is longer in the X direction than the light-converging region Cw formed by the laser light L modulated by the elliptical pattern Ew. oval shape. Here, the relatively strong elliptical pattern Es is arranged on the negative side in the Y direction rather than the axis Ax.

As shown in FIG. 18( a ), by using such a modulation pattern PE, the beam shape of the condensing region C in the YZ plane S can be made to be relative to the first plane 11a side from the center Ca. An inclined shape in which the Z direction is inclined toward the negative side of the Y direction. Especially in this case, the beam shape of the condensing region C in the YZ plane S is inclined to the negative side of the Y direction with respect to the Z direction on the opposite side of the first plane 11a from the center Ca, so that the overall become an arc. 18(b) shows the intensity distribution in the XY plane of the laser light L at each position H1 to H8 in the Z direction shown in FIG. 18(a), and is based on the actual observation results of the camera.

In addition, the modulation pattern for making the beam shape of the condensing region C into an oblique shape is not limited to the above-mentioned asymmetric pattern. As an example, as such a modulation pattern, as shown in FIG. 19 , the condensing points CI are formed at plural positions in the YZ plane S, and the entirety of the plural condensing points CI is formed (including the plural condensing points CI). ) The pattern of modulating the laser light L in the manner of the condensing area C of the inclined shape. Such a modulation pattern can be formed by an axicon lens pattern as an example. When such a modulation pattern is used, the modified region 12 itself can be formed obliquely in the YZ plane S. Therefore, in this case, the oblique crack 13 can be accurately formed according to the desired inclination. On the other hand, when such a modulation pattern is used, the length of the crack 13 tends to be shorter than that of the other examples described above. Therefore, desired processing can be achieved by using various modulation patterns as required.

The above-mentioned condensing point CI is, for example, a point where non-modulated laser light is condensed. As described above, according to the knowledge of the present inventors, in the YZ plane S, at least two modified regions 12a, 12b are displaced in the Y and Z directions, and in the YZ plane S, the beam shape of the condensing region C is With the inclined shape, it is possible to form an obliquely extending crack 13 inclined in the Y direction with respect to the Z direction.

When controlling the beam shape, when using the offset of the spherical aberration correction pattern, when using the coma aberration pattern, and using the elliptical pattern, a part of the laser beam is cut off compared to the use of the diffraction grating pattern. In this case, high-energy processing can be achieved. Furthermore, in these cases, it is effective when attaching importance to the formation of cracks. Also, in the case of using the coma aberration pattern, in the case of multifocal processing, the beam shape of only a part of the condensing area can be made to have an oblique shape. In addition, the use of the axicon pattern is effective when the formation of the modified region is more important than the use of other patterns. [An example of dressing processing]

Next, an example of the dressing process will be described. The trimming process is a process of removing unnecessary parts in the object 11 . The trimming process includes a laser processing method in which a modified region 12 is formed on the object 11 by irradiating the object 11 with a light-converging region and irradiating the object 11 with the laser light L. The object 11 includes, for example, a semiconductor wafer formed in a disk shape. The object is not particularly limited, and it can be formed of various materials and can have various shapes. A functional element (not shown) is formed on the second surface 11 b of the object 11 . The functional elements are, for example, light-receiving elements such as photodiodes, light-emitting elements such as laser diodes, circuit elements such as memories, and the like.

20 and 21 show objects to be processed. As shown in FIGS. 20 and 21 , an effective area R and a removal area E are set on the object 11 . The active region R is a portion corresponding to the semiconductor device to be acquired. The effective region R here is a disk-shaped portion including a central portion when the object 11 is viewed in the thickness direction. The removal area E is an area outside the effective area R in the object 11 . The removal area E is the outer edge portion other than the effective area R in the object 11 . The removal area E here is the annular portion surrounding the effective area R. Excluding the region E, when the object 11 is viewed from the thickness direction, the peripheral portion (bevel portion of the outer edge) is included. The setting of the effective area R and the removal area E can be performed by the control unit 6 . The effective area R and the removal area E may also be assigned coordinates.

The stage 2 is a support portion for placing the object 11 thereon. In the stage 2 of the present embodiment, the object 11 is placed in a state where the first surface 11a of the object 11 is located on the laser light incident surface side, that is, the upper side (the second surface 11b is located on the stage 2 side, that is, the lower side). Set the object 11. The stage 2 has a rotation axis Cx provided at the center thereof. The rotation axis Cx is an axis extending in the Z direction. The stage 2 can be rotated about the rotation axis Cx. The stage 2 is rotationally driven by the driving force of a known driving device such as a motor.

The irradiation unit 3 irradiates the object 11 placed on the stage 2 with the laser beam L along the Z direction, thereby forming a modified region inside the object 11 . The irradiation unit 3 is attached to the moving unit 5 . The irradiation unit 3 can be linearly moved in the Z direction by the driving force of a known driving device such as a motor. The irradiation unit 3 can be moved linearly in the X direction and the Y direction by the driving force of a known driving device such as a motor.

As described above, the irradiation unit 3 includes the spatial light modulator 7 . The spatial light modulator 7 constitutes a molding portion which is a shape of the light-converging region C in a plane perpendicular to the optical axis of the laser light L (that is, the shape of the light-converging region C when viewed from the Z direction). shape) (hereinafter also referred to as "beam shape"). The spatial light modulator 7 can shape the laser beam L so that the beam shape when viewed from the Z direction has a longitudinal direction. For example, the spatial light modulator 7 displays a modulation pattern for making the beam shape into an elliptical shape, thereby shaping the beam shape toward an elliptical shape.

The beam shape is not limited to an elliptical shape, as long as it is an elongated shape. The beam shape may also be a flat circular shape, an oblong shape or a track shape. The beam shape can also be an elongated triangular shape, a rectangular shape or a polygonal shape. The modulation pattern of the spatial light modulator 7 for realizing such a beam shape may include at least any one of a slit pattern and an astigmatic pattern. Also, when the laser light L has a plurality of condensing regions C by utilizing astigmatism or the like, the shape of the condensing region C on the most upstream side of the optical path of the laser light L among the plurality of condensing regions C is the present embodiment. Morphological beam shape (same for other lasers). The long-side direction here is the long-axis direction of the ellipse shape of the beam shape, and is also referred to as the ellipse long-axis direction.

The shape of the light beam is not limited to the shape of the condensing point, and the shape near the condensing point may be used. For example, in the case of laser light L having astigmatism, as shown in FIG. 22( a ), the beam shape has a longitudinal direction NH in the region on the laser light incident surface side near the condensing point. The beam intensity distribution in the plane of the beam shape of Fig. 22(a) (in the plane at the position in the Z direction on the side of the laser light incident surface near the condensing point) becomes a distribution with a strong intensity in the longitudinal direction NH , the direction of the stronger beam intensity is consistent with the long-side direction NH.

In the case of laser light L having astigmatism, as shown in FIG. 22(c), in the region on the opposite side of the laser light incident surface near the condensing point, the beam shape has a shape similar to that of the region on the laser light incident surface side. The longitudinal direction NH (refer to FIG. 22( a )) is the perpendicular longitudinal direction NH0 . The beam intensity distribution in the plane of the beam shape of Fig. 22(c) (in the plane at the position in the Z direction on the opposite side of the laser light incident surface near the condensing point) has a strong intensity in the longitudinal direction NH0. In the distribution of intensity, the direction with stronger beam intensity is consistent with the long-side direction NH0. In the case of the laser light L having astigmatism, as shown in FIG. 22( b ), in the region between the laser light incident surface side and the opposite surface side near the condensing point, the condensing region C has no longitudinal direction. become circular.

In the case of the laser light L having astigmatism in this way, the condensing region C targeted in this embodiment is an area on the side of the incident surface of the laser light included in the vicinity of the condensing point, and the beam shape targeted in this embodiment , is the beam shape shown in Fig. 22(a).

Furthermore, by adjusting the modulation pattern of the spatial light modulator 7, it is possible to control the desired position of the light beam shape in the light-converging region C as shown in FIG. 22(a). For example, it can be controlled so that the area on the opposite surface side of the laser light incident surface in the vicinity of the condensing point has the beam shape shown in FIG. 22( a ). For another example, it is possible to control the region between the laser light incident surface side and the opposite surface side in the vicinity of the condensing point to have the beam shape shown in FIG. 22( a ). The position of a part of the condensing region C is not particularly limited, and may be any position from the laser light incident surface of the object 11 to the opposite surface.

For another example, in the case of using the control of the modulation pattern and/or the slit or elliptical optical system based on the mechanical mechanism, as shown in FIG. The beam shape has a long-side direction NH. The beam intensity distribution in the plane of the beam shape in Fig. 23(a) (in the plane at the position in the Z direction on the side of the laser light incident surface near the condensing point) becomes a distribution with a strong intensity in the longitudinal direction NH , the direction of the stronger beam intensity is consistent with the long-side direction NH.

In the case of using a slit or elliptical optical system, as shown in Fig. 23(c), in the area on the opposite side of the laser light incident surface near the condensing point, the beam shape has a difference between the beam shape and the area on the laser light incident surface side. The longitudinal direction NH (refer to FIG. 22( a )) is the same as the longitudinal direction NH. The beam intensity distribution in the plane of the beam shape shown in Fig. 23(c) (in the plane at the position in the Z direction on the opposite side of the laser light incident surface near the condensing point) has a strong distribution in the longitudinal direction NH. In the distribution of intensity, the direction where the beam intensity is stronger is consistent with the long-side direction NH. In the case of using a slit or elliptical optical system, as shown in FIG. 23(b), the beam shape at the condensing point has the longitudinal direction NH of the region on the side of the incident surface of the laser light (refer to FIG. 23(a)) Vertical long-side direction NH0. The beam intensity distribution in the plane of the beam shape in Fig. 23(b) (in the plane of the Z direction position of the condensing point) becomes a distribution with a strong intensity in the longitudinal direction NH0, and a direction in which the beam intensity is strong Consistent with the longitudinal direction NH0.

When such a slit or elliptical optical system is employed, the beam shape other than the condensing point has a longitudinal direction, and the beam shape other than the condensing point is the beam shape targeted by this embodiment. That is, a part of the condensing area C that is targeted in this embodiment is an area on the side of the laser light incident surface near the condensing point, and the beam shape targeted in this embodiment is as shown in FIG. 23(a) . the beam shape shown.

In the trimming process, the control unit 6 controls the rotation of the stage 2 , the irradiation of the laser light L from the irradiation unit 3 , the beam shape, and the movement of the condensing area C. The control unit 6 can perform various controls based on rotation information (hereinafter also referred to as "θ information") related to the rotation amount of the stage 2 . The θ information can be obtained according to the driving amount of the driving device for rotating the stage 2, or it can be obtained by another sensor or the like. The θ information can be obtained by various known methods. The θ information here includes a rotation angle based on the state when the object 11 is positioned in the 0° direction.

The control unit 6 controls the irradiation unit 3 based on the θ information in a state where the condensing area C is positioned along the line A (periphery of the effective area R) of the object 11 while rotating the stage 2 . The irradiation of the laser light L is started and stopped, whereby peripheral processing for forming a modified region along the peripheral edge of the effective region R is performed.

The controller 6 executes the removal process for forming the modified region in the removal region E by irradiating the removal region E with the laser light L and moving the condensing region C of the laser light L without rotating the stage 2 .

The control unit 6 controls the rotation of the stage 2 and the transmission from the irradiation unit 3 in such a manner that the pitch of the plurality of modified spots included in the modified region (the interval between adjacent modified spots in the machining progress direction) becomes constant. At least one of the irradiation of the laser light L and the movement of the condensing region C.

The control unit 6 acquires the reference position (position in the 0° direction) in the rotation direction of the object 11 and the diameter of the object 11 based on the image captured by the alignment camera (not shown). The control part 6 controls the movement of the irradiation part 3 so that the irradiation part 3 can move to the rotation axis Cx of the stage 2 along the X direction.

Next, an example of the dressing process will be described. First, the object 11 is placed on the stage 2 so that the first surface 11 a becomes the laser light L incident surface. On the second surface 11b side of the object 11 on which the functional element is mounted, a support substrate or a tape material is adhered and protected.

Next, trim processing is performed. In the trimming process, peripheral edge processing is performed by the control unit 6 . Specifically, as shown in FIG. 24( a ), while the stage 2 is rotated at a constant speed, the condensing region C is located at a position along the periphery of the effective region R of the object 11 . The start and stop of the irradiation of the laser beam L in the irradiation unit 3 is controlled based on the θ information. Thereby, as shown in FIGS. 24( b ) and 24 ( c ), the modified region 12 is formed along the line A (periphery of the effective region R). The formed modified region 12 includes modified spots and cracks extending from the modified spots.

In the trimming process, removal processing is performed by the control unit 6 . Specifically, as shown in FIG. 25( a ), without rotating the stage 2 , the removal area E is irradiated with the laser light L, and the irradiation unit 3 is moved in the X direction to make the laser light L condensed area C moves relative to the object 11 in the X direction. After the stage 2 is rotated by 90°, the removal area E is irradiated with laser light L, and the irradiation unit 3 is moved in the X direction, so that the condensing area C of the laser light L is relatively moved in the X direction with respect to the object 11 .

Thereby, as shown in FIG.25(b), the modified area|region 12 is formed along the line extended so that the removal area|region E may be divided into quarters when it sees from the Z direction. The formed modified region 12 includes modified spots and cracks extending from the modified spots. This crack may reach at least any one of the 1st surface 11a and the 2nd surface 11b, and may not reach at least any one of the 1st surface 11a and the 2nd surface 11b. After that, as shown in FIGS. 26( a ) and 26 ( b ), the removal region E is removed with the modified region 12 as a boundary, for example, using a jig or an air (air). Thereby, the semiconductor device 11K is formed from the object 11 .

Next, as shown in FIG.26(c), the peeling surface 11c of the semiconductor device 11K is grind|polished by the grinding|polishing of finishing, or grinding|polishing by abrasive material KM, such as a grindstone. When the object 11 is peeled off by etching, the polishing can be simplified. As a result of the above, the semiconductor device 11M was obtained.

Next, the trimming process will be described in more detail. As shown in FIG. 27 , the object 11 has a plate shape. The object 11 has a crystal structure including a (100) plane, one (110) plane, the other (110) plane, a first crystal orientation K1 orthogonal to the one (110) plane, and the other (110) plane. 110) The second crystal orientation K2 in which the planes are orthogonal. The first surface 11a of the object 11 is a (100) surface. The object 11 is supported by the stage 2 so that the (100) surface (that is, the first surface 11 a ) becomes the laser light L incident surface. The object 11 is, for example, a silicon wafer formed of silicon. The (110) plane is the split plane. The first crystal orientation K1 and the second crystal orientation K2 are the cleavage directions, that is, the directions in which the cracks are most likely to extend in the object 11 . The first crystal orientation K1 and the second crystal orientation K2 are orthogonal to each other.

An alignment object 11 n is set on the object 11 . For example, the alignment object 11n has a certain relationship with respect to the position of the object 11 in the 0° direction in the θ direction (the rotation direction around the rotation axis Cx of the stage 2 ). The position in the 0° direction is the position of the reference object 11 in the θ direction. For example, the alignment object 11n is a notch formed in the outer edge portion. The alignment object 11n is not particularly limited, and may be an orientation plane of the object 11 or a pattern of functional elements. In the example shown in the figure, the alignment object 11n is set at a position in the 0° direction of the object 11 . In other words, the alignment target 11n is set at a position where the outer edge of the target object 11 and the second crystal orientation K2 are perpendicular to each other.

In the object 11, a line A as a line to be trimmed is set. Line A is a line where the modified region 12 is to be formed. The line A extends annularly inside the outer edge of the object 11 . The line A here extends in an annular shape. The line A is set at the boundary between the effective area R and the removal area E of the object 11 . The setting of the line A can be performed by the control unit 6 . Although the line A is an imaginary line, it may be an actual line drawn. Line A can also be the assigned coordinate.

The control unit 6 acquires object information related to the object 11 . The object information includes, for example, information about the crystal orientation of the object 11 (the first crystal orientation K1 and the second crystal orientation K2 ), the alignment about the position of the object 11 in the 0° direction, and the diameter of the object 11 Information. The control unit 6 can acquire the object information based on the image captured by the camera for alignment, and the input based on the user's operation or the communication from the outside.

Further, the control unit 6 acquires line information related to the line A. The line information includes information on the line A, and when the light-converging region C is relatively moved along the line A, the information on the movement direction (also referred to as the "processing direction") of the movement. For example, the processing progress direction is the tangential direction of the line A passing through the light-converging region C located on the line A. The control part 6 can acquire the line information based on the input based on a user's operation, communication from the outside, or the like.

Furthermore, the control unit 6 determines the relative movement of the condensing area C along the line A so that the longitudinal direction of the beam shape intersects the processing progress direction based on the acquired object information and line information. The orientation of the long side of the situation. Specifically, the control unit 6 determines the orientation of the longitudinal direction NH as the first orientation and the second orientation based on the object information and the line information. The first orientation is the orientation in the longitudinal direction of the beam shape when the condensing region C is relatively moved along the first region A1 of the line A. The second orientation is the orientation in the longitudinal direction of the beam shape when the condensing region C is relatively moved along the second region A2 of the line A. Hereinafter, "the direction of the longitudinal direction of the beam shape" is also simply referred to as "the direction of the beam shape".

The first region A1 is an arc-shaped region, and as an example, the point at which the second crystal orientation K2 and the line A are orthogonal is set at 0°, and the point at which the first crystal orientation K1 and the line A are orthogonal is set at 90° , when the point between 0° and 90° on line A is set to 45°, the first area A1 includes: the area of 0°~45°, the area of 90°~135°, the area of 180°~225°, And the area of 270˚~315˚. The second area A2 is an arc-shaped area, and includes a 45˚~90˚ area, a 135˚~180˚ area, a 225˚~270˚ area, and a 315˚~360˚ area. Also in this case, the 45° point and the 225° point are the points orthogonal to the third crystal orientation K3 orthogonal to the (100) plane and the line A; the 135° point and the 315° point are the (100) plane points. A point where the fourth crystal orientation K4 and the line A are orthogonal to each other.

In this way, the line A includes a plurality of first areas A1 and a plurality of second areas A2 alternately arranged at intervals of 45° in the counterclockwise direction. However, the above-mentioned angular ranges of the first area A1 and the second area A2 can be arbitrarily changed according to where the 0° point is set. For example, when the point at which the first crystal orientation K1 is perpendicular to the line A is set to 0° (the above-mentioned 90° point is set to 0°), the first area A1 and the second area A2 are in the angle range from the above-mentioned angle. Angular range after 90˚ rotation. When the 0° point is set as described above, the 315° point of the point rotated 45° clockwise from the 0° point can also be called the -45° point. In addition, the boundary (for example, 45°) point of the first area A1 and the second area A2 may be included in either one of the first area A1 and the second area A2, or may be included in both.

The first area A1 includes the area where the processing angle described later is 0° to 45°, or -90° to -45°, when the light-converging area C is relatively moved along the line A. The second area A2, when the light-converging area C is relatively moved along the line A, includes the area where the processing angle described later is 45° or more and less than 90° or -45° or more and less than 0°.

As shown in FIG. 28( b ), the machining angle α is an angle with respect to the machining progress direction ND of the first crystal orientation K1 . The processing angle α, when viewed from the Z direction intersecting the first surface 11a, which is the incident surface of the laser light L, is a positive (+) angle in the counterclockwise direction, and a positive (+) angle in the clockwise direction. Negative (-) angle. The machining angle α can be obtained from the θ information, the object information, and the line information of the stage 2 . When the condensing area C is moved relatively along the first area A1, for example, the processing angle α can be regarded as a case where the processing angle α is 0° to 45° or -90° to -45°. When the condensing area C is moved relatively along the second area A2, for example, the processing angle α can be regarded as a case where the processing angle α is 45° to 90° or -45° to 0°.

The first orientation and the second orientation are relative to the machining progression direction so as to be closer to the larger (farther away) angle between the first crystal orientation K1 and the second crystal orientation K2 and the machining progression direction ND. ND is oriented in an oblique direction.

The first and second orientations are as follows when the machining angle α is 0° to 90°. The first orientation is the orientation of the direction in which the longitudinal direction NH is inclined with respect to the machining progress direction ND toward the side close to the second crystal orientation K2. The second orientation is a direction in which the longitudinal direction NH is inclined with respect to the machining progress direction ND toward the side close to the first crystal orientation K1. The first orientation is, for example, an orientation in a direction inclined by 10° to 35° toward the side close to the second crystal orientation K2 from the machining progress direction ND. The second direction is, for example, a direction inclined by 10° to 35° toward the side close to the first crystal orientation K1 from the machining progress direction ND.

The first orientation is the orientation of the condensing area C when the beam angle β is +10° to +35°. The second orientation is the orientation of the condensing area C when the beam angle β is -35° to -10°. The beam angle β is the angle between the machining progress direction ND and the long-side direction NH. The beam angle β, when viewed from the Z direction intersecting the first surface 11a, which is the incident surface of the laser light L, is the positive (+) angle for the counterclockwise angle and the positive (+) angle for the clockwise angle Negative (-) angle. The beam angle β can be obtained from the orientation of the condensing region C and the processing progress direction ND.

The control unit 6 controls the start and stop of the laser processing on the object 11 . The control unit 6 executes a first processing of relatively moving the light-condensing region C along the first region A1 of the line A to form the modified region 12 and causing the modified region 12 to be formed outside the first region A1 of the line A The formation of the modified region 12 in the region is stopped. The control unit 6 executes a second processing for forming the modified region 12 by relatively moving the condensing region C along the second region A2 of the line A, and causing the modified region 12 to be formed outside the second region A2 of the line A. The formation of the modified region 12 in the region is stopped.

The formation of the modified region 12 by the control unit 6 and the switching of the stop thereof can be realized as described below. For example, by switching the start and stop (ON/OFF) of the irradiation (output) of the laser light L in the irradiation unit 3 , the formation of the modified region 12 and the stop of the formation can be switched. Specifically, when the laser oscillator is composed of a solid-state laser, the Q switch (AOM (Acousto-Optic Modulator), EOM (Electro-Optic Modulator), etc.) provided in the resonator By switching ON/OFF, the start and stop of the irradiation of the laser beam L can be switched at high speed. When the laser oscillator is composed of a fiber laser, by switching ON/OFF the output of the semiconductor laser constituting the seed laser and the amplifier (excitation) laser, the The start and stop of the irradiation of the laser beam L are switched at high speed. When the laser oscillator uses an external modulation element, by switching the ON/OFF of the external modulation element (AOM, EOM, etc.) provided outside the resonator, the ON/OFF of the irradiation of the laser light can be quickly turned ON/OFF. switch.

Alternatively, the formation of the modified region 12 and the switching of the stop thereof by the control unit 6 may be realized as described below. For example, by controlling a mechanical mechanism such as a shutter to open and close the optical path of the laser light L, the formation of the modified region 12 and the stop of the formation are switched. It is also possible to switch the laser light L to CW light (continuous wave), thereby stopping the formation of the modified region 12 . It is also possible to display on the liquid crystal layer 76 of the spatial light modulator 7: a pattern that makes the condensing state of the laser light L into a state that cannot be modified (for example, a pear-like pattern that scatters the laser light), thereby allowing the modification The formation of region 12 is stopped. It is also possible to control the power adjustment section of the attenuator or the like to reduce the output of the laser light L so that the modified region cannot be formed, thereby stopping the formation of the modified region 12 . The polarization direction can also be switched to stop the formation of the modified region 12 . The formation of the modified region 12 may be stopped by scattering (spreading) the laser light L in a direction other than the optical axis to stop it.

The control unit 6 adjusts the orientation of the light condensing region C by controlling the spatial light modulator 7 . The control unit 6 adjusts the orientation of the condensing region C so as to be the first orientation when the first processing is executed. The control unit 6 adjusts the orientation of the light-converging region C so as to be the second orientation when the second processing is executed. As an example, the control unit 6 adjusts the longitudinal direction NH of the light-converging region C so as to vary within a range of ±35° with respect to the machining progress direction ND.

In the above-mentioned laser processing apparatus 1, the following trimming processing is performed.

In the trimming process, first, the stage 2 is rotated and the irradiation unit 3 mounted on the camera is rotated so that the camera for alignment is positioned directly above the alignment target 11n of the target object 11 and the camera is focused on the alignment target 11n. Move along the X and Y directions.

Next, imaging is performed with a camera for alignment. The position of the object 11 in the 0° direction is obtained from the captured image of the camera. The control unit 6 acquires object information and line information based on an image captured by a camera, and an input based on a user's operation or communication from the outside. The object information includes the position of the object 11 in the 0° direction and alignment information related to the diameter. As described above, since the alignment target 11n has a certain relationship in the θ direction with respect to the position in the 0° direction, the position in the 0° direction can be obtained by acquiring the position of the alignment target 11n from the captured image. The diameter of the object 11 can be obtained from the captured image of the camera. In addition, the diameter of the object 11 may be set by the input from the user.

Next, based on the acquired object information and line information, the control unit 6 determines the first orientation and the second orientation as the length of the condensing area C when the condensing area C is relatively moved along the line A The direction of the edge direction NH.

Next, the stage 2 is rotated so that the object 11 is positioned in the 0° direction. The irradiation unit 3 is moved in the X direction and the Y direction so that the light condensing area C is positioned at a predetermined trimming position in the X direction. For example, the predetermined trimming position is a predetermined position on the line A in the object 11 .

Next, the rotation of the stage 2 is started. Tracking by the first surface 11a of the ranging sensor (not shown) is started. Also, before starting the tracking of the distance measuring sensor, it is confirmed in advance that the position of the light-converging area C is within the measurement range of the distance measuring sensor. When the rotational speed of the stage 2 becomes constant (constant speed), the irradiation of the laser light L by the irradiation unit 3 starts.

While the stage 2 is being rotated, ON/OFF of the irradiation of the laser beam L is switched by the control unit 6, as shown in FIG. C moves relatively to form the modified region 12, and stops the formation of the modified region 12 in the region other than the first region A1 of the line A (first processing step). As shown in FIG. 28( b ), when the first processing step is performed, the orientation of the light-converging region C is adjusted by the control unit 6 so as to be the first orientation. That is, the orientation of the light-condensing region C in the first processing step is fixed to the first orientation.

Next, while the stage 2 is rotated, ON/OFF of the irradiation of the laser beam L is switched by the control unit 6, as shown in FIG. 29(a), along the second area A2 in the line A The light-converging region C is relatively moved to form the modified region 12, and the formation of the modified region 12 in the region other than the first region A1 of the line A is stopped (second processing step). As shown in FIG. 29( b ), when the second processing step is performed, the orientation of the light-converging region C is adjusted by the control unit 6 so as to be the second orientation. That is, the orientation of the light-condensing region C in the second processing step is fixed to the second orientation.

The above-described first processing step and second processing step are repeated by changing the position in the Z direction of the trimming predetermined position. As a result of the above operations, a plurality of rows of modified regions 12 are formed in the Z direction along the line A of the periphery of the effective region R inside the object 11 . [The first embodiment of laser processing]

The above has explained the knowledge related to the formation of the oblique crack and an example of the trimming process. Here, an embodiment of laser processing for forming oblique cracks at the time of trimming will be described. FIG. 30 shows an object of laser processing according to an embodiment. Fig. 30(a) is a plan view, and Fig. 30(b) is a side view. FIG. 31 is a cross-sectional view of the object shown in FIG. 30 .

As shown in FIGS. 30 and 31 , the object 100 includes the object 11 described above, and an object 11R that is a different member from the object 11 . The object 11R is, for example, a silicon wafer. The object 11 includes a plurality of functional elements and includes the device layer 110 formed on the second surface 11b. The object 11R includes a plurality of functional elements, and includes the device layer 110R formed on the first surface 11Ra of the object 11R. The object 11 and the object 11R are arranged so that the device layer 110 and the device layer 110R are opposed to each other, and are bonded together by being bonded to each other, thereby constituting the object 100 .

Here, the modified region 12 and the cracks 13 extending from the modified region 12 are formed in the object 11, and the removal region E of the object 11 is excised with these modified regions 12 and cracks 13 as boundaries. Finishing processing. More specifically, the object 11 includes a first part 15A and a second part arranged in order from the second surface 11b (opposite surface) side on the opposite side of the first surface 11a serving as the incident surface of the laser light L 15B. Further, in the first portion 15A, the modified region 12 is formed so as to form cracks 13 extending obliquely with respect to the Z-direction (hereafter referred to as "oblique cracks"); in the second portion 15B , the formation of the modified region 12 is performed so as to form cracks 13 extending along the Z direction (hereinafter referred to as "vertical cracks"). Also, the line R1 in FIG. 31 represents a line intended to form an oblique crack, and the line R2 represents a line intended to form a vertical crack.

Therefore, in the processing of at least the first portion 15A, the above-mentioned trimming processing and processing for generating diagonal cracks are used in combination. That is, in the machining of the first portion 15A, the longitudinal direction NH is set to be close to the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the machining advancement direction ND, and is relative to the machining advancement direction. With the ND inclination, the beam shape is shaped, and the modified region 12 and the crack 13 are formed along the line A, and the crack 13 becomes an oblique crack.

More specifically, when processing the first region A1 of the line A, the laser light L is irradiated so as to become the light-condensing region C of the first shape Q1 in the first orientation as shown in FIG. 28( b ). In the case of processing the second area A2 of the line A, the laser beam L is formed so as to become the condensing area C of the second shape Q2 in the second direction as shown in FIG. 29(b). . In the case of processing in this way, the processing test described below was carried out.

FIG. 32 is a plan view of the object shown in FIG. 30 . As shown in FIG. 32, here, for the line A from the intersection of the line A and the second crystal orientation K2, that is, the 0° point to the intersection of the line A and the fourth crystal orientation K4, that is, up to the -45° point In the second area A2, when the processing progress direction ND is set to the forward direction ND1 and the light-converging area C is relatively moved, and when the processing progress direction ND is set to the reverse direction ND2 and the light-converging area C is relatively moved, respectively Actual processing was performed and cross-sectional observation was performed. Here, in order to process the second region A2, the light-converging region C has a second shape Q2 shown in FIG. 29(b). Further, the extending direction CD of the diagonal crack is a direction from the center side of the object 11 to the outside (see FIG. 29( b )).

Therefore, as shown in FIG. 29( b ), when the machining progress direction ND is the forward direction ND1 , the direction of the inclination of the longitudinal direction NH of the light-converging region C with respect to the machining progress direction ND and the direction of the oblique cracks The extending direction CD is on the same side, and on the other hand, when the machining progress direction ND is the reverse direction ND2 (the direction of the arrow in the machining progress direction ND is opposite), the longitudinal direction NH is inclined with respect to the machining progress direction ND The direction of , and the extending direction CD of the diagonal cracks are opposite to each other. Further, the forward direction ND1 is set to be in the counterclockwise direction, and the reverse direction ND2 is set to be in the clockwise direction.

33 and 34 show cross-sectional photographs of the processing results. Fig. 33 shows the processing results of ND1 in the forward direction, and Fig. 33(a)~(d) are the cross-sectional photos at the 0° point, the -15° point, the -30° point, and the -45° point, respectively. Figure 34 also shows the processing results of ND2 in the reverse direction. Figure 34(a)~(d) are the cross-sectional photos of the 0° point, the -15° point, the -30° point, and the -45° point, respectively.

As shown in Figs. 33 and 34, when the direction of the longitudinal direction NH and the extending direction CD of the diagonal cracks are the same side as the machining progress direction ND, the machining in the forward direction ND1 is good from 0° to -45°. However, the direction of the longitudinal direction NH and the extension direction CD of the diagonal cracks are opposite to the machining progress direction ND, and the machining results in the opposite direction ND2 are at the -45° point (Fig. 34(d)). Asperities FN reaching the lower surface were generated, and it was confirmed that quality degradation occurred. Therefore, it is understood that the relationship between the direction of the inclination of the longitudinal direction NH with respect to the working progress direction ND and the extending direction CD of the diagonal crack with respect to the working progress direction ND affects the working quality. Based on this understanding, other processing tests were performed.

Fig. 35 is a schematic diagram for explaining a processing test. Fig. 36 is a schematic diagram showing the relationship between the machining progress direction and the beam shape and the oblique crack in the machining test. As shown in Figs. 35 and 36, in this machining test, when viewed from the Z direction, the direction of 45° with respect to the (110) plane is referred to as the machining progress direction ND, and about the forward direction ND1 and the reverse direction ND2, respectively, The processing was carried out in the case where the extending direction CD of the oblique crack was set as the positive direction CD1 and the case where it was set as the reverse direction CD2, respectively. That is, for a total of four combinations of two types of forward and reverse in the processing progress direction ND and two types of forward and reverse in the extending direction CD of the diagonal crack, the beam shape of the condensing region C is further made into the first shape. Processing in the case of Q1 and in the case of using the second shape Q2 (8 types of processing in total).

Figure 37 is a table showing the results of the processing tests shown in Figures 35, 36. As shown in FIG. 37 , for a total of eight types of processing, when the extending direction CD of the diagonal crack is set as the positive direction CD1, the beam shape of the condensing region C is set as the second shape Q2, and the processing is advanced. When the direction ND is the forward direction ND1, and when the beam shape of the condensing region C is the first shape Q1 and the machining progress direction ND is the reverse direction ND2, good machining results can be obtained (Table of FIG. 37 ). "A" in).

In addition, for a total of 8 types of processing, when the extending direction CD of the diagonal crack is the reverse direction CD2, the beam shape of the condensing region C is the first shape Q1 and the processing progress direction ND is the forward direction. In the case of ND1 and the case where the beam shape of the condensing region C is the second shape Q2 and the machining progress direction ND is the reverse direction ND2, good machining results can be obtained. In this way, the following knowledge is obtained. When processing at least 45° points, the forward and reverse directions of the processing progress direction ND are adjusted, and the direction of the inclination of the longitudinal direction NH of the light-converging region C with respect to the processing progress direction ND and the direction of the diagonal cracks are adjusted. When the extending direction CD is on the same side, a good processing result can be obtained.

When the point at which the second crystal orientation K2 and the line A are orthogonal is set to 0°, the 45° point is the point where the third crystal orientation K3 orthogonal to the (100) plane is orthogonal to the line A, which is equivalent to the same The point at which the fourth crystal orientation K4 orthogonal to the (100) plane is orthogonal to the line A, that is, the -45° point.

Based on the above knowledge, further processing tests were carried out. Figure 38 is a table showing the results of the processing tests. Among the conditions shown in the table of FIG. 38 , the conditions for setting the beam shape to the first shape Q1 in the first area A1 and the conditions for setting the beam shape to the second shape Q2 in the second area A2 are relative to the processing Under the conditions IR1 and IR2 where the direction of the inclination of the longitudinal direction NH of the light-converging region C and the extending direction CD of the oblique cracks are on the same side as the progress direction ND, good processing results were obtained (evaluation in the table of FIG. 38 ). "A" or rating "B"). In the evaluation shown in FIG. 38, the order of goodness is evaluation "A", evaluation "B", evaluation "C", evaluation "D", and evaluation "E" (that is, evaluation "A" is the best, The rating "E" is the least favorable).

The condition IR1 is that the machining progress direction ND is the forward direction for the second region A2 from the 0° point to the -45° point when the point at which the first crystal orientation K1 and the line A are orthogonal is set to 0°. ND1 and the beam shape of the condensing region C is the second shape Q2. In addition, the condition IR2 is to set the machining progress direction ND as the first region A1 from the -45° point to the -90° point when the point at which the first crystal orientation K1 and the line A are orthogonal is set to 0°. The beam shape of the condensing region C is the first shape Q1 in the reverse direction ND2.

On the other hand, among the conditions shown in the table of FIG. 38 , as long as the beam shape is the first shape Q1 in the first area A1, and the beam shape is the second shape Q2 in the second area A2 Under the same conditions, even if the direction of the inclination of the longitudinal direction NH of the light-converging region C and the extending direction CD of the oblique cracks are not on the same side with respect to the processing progress direction ND, the conditions IR3 and IR4 are smaller than those of the conditions IR1 and IR4. Conditional IR2 is poor, but generally good machining results are obtained except for the -45˚ point. On the other hand, among the conditions shown in the table of FIG. 38 , the condition IR5 in which the beam shape is the second shape Q2 in the first area A1 and the condition IR5 in which the beam shape is the first shape Q1 in the second area A2 Condition IR6, regardless of the forward or reverse direction of the processing progress direction ND, could not obtain a good result.

Also, Fig. 39(a) is an example of a cross-sectional photograph corresponding to the evaluation "E" in the table of Fig. 38, and Fig. 39(b) is an example of a cross-sectional photograph corresponding to the evaluation "D" in the table of Fig. 38. 39(c) is an example of a cross-sectional photograph corresponding to the evaluation "C" in the table of Fig. 38, Fig. 39(d) is an example of a cross-sectional photograph corresponding to the evaluation "B" in the table of Fig. 38, Fig. 39 ( e) is an example of a cross-sectional photograph corresponding to the evaluation "A" in the table of Fig. 38 . As shown in FIG. 39, the evaluation "A" and the evaluation "B" did not form the unevenness|corrugation which reached the lower surface, but showed favorable processing results. In the evaluation "C", although unevenness reaching the lower surface was slightly generated, it showed a generally good result. On the other hand, the evaluation "D" and the evaluation "E" produced a relatively large amount of unevenness reaching the lower surface, and showed unfavorable results.

From the results of the processing tests shown in Figs. 38 and 39, it was confirmed that the knowledge obtained from the results of the processing tests shown in Fig. 37 was correct.

In the present embodiment, laser processing is performed based on the above-mentioned knowledge. Here, first, processing of the first portion 15A (see FIG. 31 ) of the object 11 is performed. That is, while the stage 2 is rotated, ON/OFF of the irradiation of the laser beam L is switched by the control unit 6, as shown in FIG. The light-condensing region C is relatively moved to form the modified region 12, and the formation of the modified region 12 in the region (second region A2) other than the first region A1 of the line A is stopped (first processing).

As shown in FIG. 40( b ), in the first machining, the rotational direction of the stage 2 is controlled based on the control of the moving portion 4 by the control portion 6 so that the machining progress direction ND is the reverse direction ND2 . In the first processing, since it is processing of the first area A1, the laser light L by the spatial light modulator 7 is shaped under the control of the control unit 6, and the beam shape of the condensing area C becomes the first shape. Q1. In addition, here, the extending direction CD of the oblique crack is made positive so that the direction from the center of the object 11 to the outside in the Z direction is inclined toward the second surface 11b (see FIG. 31 ). Direction CD1.

The formation method of the diagonal crack here is demonstrated concretely. That is, in the first processing, as shown in FIG. 41 , the position of the light-condensing region C1 in the Z direction intersecting with the incident surface of the laser light L1 in the object 11 , that is, the first surface 11 a is set as the first processing. The modified region (first modified region) 12a and the cracks (first cracks) extending from the modified region 12a are moved relative to the 1Z position Z1 along the line A (X direction). ) 13a is formed on the object 11 (first formation). In this first formation, the position of the light-condensing region C1 in the Y direction intersecting the X direction along the first surface 11a is set as the first Y position Y1.

Furthermore, in the first processing, the position of the condensing region C2 of the laser light L2 in the Z direction is set to be closer to the first surface 11a (incident surface) than the first Z position Z1 of the condensing region C1 formed first. The modified region 12b (second modified region) and the cracks (second modified region 12b) extending from the modified region 12b are moved relatively crack) 13b is formed (second formation). In this second formation, the position of the light condensing region C2 in the Y direction is set to the second Y position Y2 shifted from the first Y position Y1 of the light condensing region C1. In the second formation, the laser light L2 is modulated so that the beam shape of the condensing region C2 in the YZ plane S including the Y direction and the Z direction is at least closer to the first than the center of the condensing region C2. The surface 11a side has an inclined shape inclined in the direction of the displacement (the beam shape of the condensing region C2 when viewed from the Z direction is the first shape Q1). Thereby, the cracks 13 are formed in the YZ plane S so as to be inclined in the direction of the displacement. The control of the beam shape in the YZ plane S is as explained in the above-mentioned knowledge about the oblique crack.

Here, in the first formation, similarly to the second formation, the laser light L1 is modulated, and the beam shape of the light-converging region C1 in the YZ plane S including the Y-direction and the Z-direction is at least higher than the condensing region C1. The center of the light area C1 has an inclined shape inclined in the direction of the displacement further on the first surface 11a side (also in this case, the beam shape of the light condensing area C1 when viewed from the Z direction is the first shape Q1). By the above operation, as shown in FIG. 41(b), the crack 13a and the crack 13b are connected to each other in the first region A1 of the line A, and the crack 13 ( Oblique crack 13F). The oblique crack 13F may reach or not reach the second surface 11b of the object 11 (it can be appropriately set in accordance with the required processing state).

For example, the spatial light modulator 7 can display a pattern for branching the laser light L to modulate the laser light L, thereby branching the laser light L into two beams to generate the laser light L1 and L2. In this case, the first formation and the second formation are performed simultaneously. However, the laser lights L1 and L2 may be different laser lights, and in this case, the first formation and the second formation are performed at different timings. Further, the condensing regions C1 and C2 are condensing regions of the laser light L1 and L2 corresponding to the light condensing region C of the laser light L, respectively.

On the other hand, in the present embodiment, while the stage 2 is rotated, ON/OFF of the irradiation of the laser beam L is switched by the control unit 6, as shown in FIG. 42(a), along the line A In the second area A2 of the line A, the light-condensing area C is relatively moved to form the modified area 12, and the formation of the modified area 12 in the area other than the second area A2 of the line A (the first area A1) is stopped (second processing) .

As shown in FIG. 42( b ), in the second machining, the rotational direction of the stage 2 is controlled based on the control of the moving portion 4 by the control portion 6 , thereby making the machining progress direction ND the forward direction ND1 . That is, between the first machining and the second machining, the forward and reverse directions of the machining progress direction ND (whether it becomes the forward direction ND1 or the reverse direction ND2) are switched. In the second processing, since it is processing of the second area A2, the laser light L by the spatial light modulator 7 is shaped under the control of the control unit 6, thereby making the beam shape of the condensing area C the second one. Shape Q2. In addition, here, the extending direction CD of the oblique crack is made positive so that the direction from the center of the object 11 to the outside in the Z direction is inclined toward the second surface 11b (see FIG. 31 ). Direction CD1.

The formation method of the diagonal crack here is demonstrated concretely. That is, in the second processing, as shown in FIG. 43( a ), the position of the condensing region C1 in the Z direction intersecting with the incident surface of the laser light L1 in the object 11 , that is, the first surface 11 a The modified region (the first modified region) 12a and the crack (the first modified region) extending from the modified region 12a are separated by relatively moving the light-converging region C1 along the line A (X direction) by setting the first Z position Z1. 1 crack) 13a is formed in the object 11 (1st formation). In this first formation, the position of the light-condensing region C1 in the Y direction intersecting the X direction along the first surface 11a is set as the first Y position Y1.

In the second formation, the position of the condensing region C2 of the laser light L2 in the Z direction is set to be closer to the first surface 11a (incidence surface) than the first Z position Z1 of the light condensing region C1 formed in the first. The modified region 12b (second modified region) and the cracks (second modified region 12b) extending from the modified region 12b are moved relatively crack) 13b is formed (second formation). In this second formation, the position of the light condensing region C2 in the Y direction is set to the second Y position Y2 shifted from the first Y position Y1 of the light condensing region C1. In the second formation, the laser light L2 is modulated so that the beam shape of the condensing region C2 in the YZ plane S including the Y direction and the Z direction is at least closer to the first than the center of the condensing region C2. The surface 11a side has an inclined shape inclined in the direction of the displacement (the beam shape of the condensing region C2 when viewed from the Z direction is the second shape Q2). Thereby, the cracks 13 are formed in the YZ plane S so as to be inclined in the direction of the displacement.

Here, in the first formation, similarly to the second formation, the laser light L1 is modulated, and the beam shape of the light-converging region C1 in the YZ plane S including the Y-direction and the Z-direction is at least higher than the condensing region C1. The center of the light area C1 has an inclined shape inclined in the direction of the displacement further on the first surface 11a side (also in this case, the beam shape of the light condensing area C1 when viewed from the Z direction is the second shape Q2). By the above operation, as shown in FIG. 43(b), the crack 13a and the crack 13b are connected to each other in the second region A2 of the line A, and the crack 13 ( Oblique crack 13F). The crack 13 may reach or not reach the second surface 11b of the object 11 (it can be appropriately set according to the required processing state). The modulation pattern, which is also used to make the beam shape into an oblique shape, is as described above.

That is, the modulation pattern here may include a coma aberration pattern for imparting coma aberration to the laser light L, and in at least the second formation, the control unit 6 controls the coma aberration pattern based on the coma aberration pattern. The magnitude of the aberration is used to perform the first pattern control for making the beam shape of the condensing region C2 into an oblique shape. As described above, imparting coma aberration to the laser light L is synonymous with the offset of the spherical aberration correction pattern.

Therefore, the modulation pattern here may include a spherical aberration correction pattern Ps for correcting the spherical aberration of the laser light L, which is formed at least in the second, and the control portion 6 is relative to the entrance pupil surface of the condenser lens 33 . The center Pc of the spherical aberration correction pattern Ps is offset in the Y direction at the center of 33a, thereby performing the second pattern control for making the beam shape of the condensing region C2 an inclined shape.

Alternatively, in the second formation, the control unit 6 displays an asymmetric modulation pattern with respect to the axis Ax along the X-direction on the spatial light modulator 7, thereby performing the control for making the light-converging region C2 The beam shape becomes the oblique shape of the third pattern control. The modulation patterns that are asymmetric about the axis Ax may be modulation patterns PG1 to PG4 including grid patterns Ga, modulation patterns PE including elliptical patterns Es and Ew (or both).

That is, the modulation pattern here may include elliptical patterns Es, Ew for making the beam shape of the condensing region C in the XY plane an elliptical shape with the X direction as the long side, and are formed in the second, The control unit 6 displays the modulation pattern PE on the spatial light modulator 7 so that the intensities of the elliptical patterns Es and Ew are asymmetrical with respect to the axis Ax along the X direction, thereby performing a light beam for making the light-condensing region C2 The shape becomes the fourth pattern control of the oblique shape.

Furthermore, in the second formation, the control unit 6 may display on the spatial light modulator 7 a modulation pattern for forming a plurality of light-converging regions C arranged in the direction of displacement in the YZ plane S. (for example, the above-mentioned cone mirror pattern PA), the fifth pattern control for making the beam shape of the condensing region C into an oblique shape is performed thereby. The above-mentioned various patterns can be arbitrarily combined and overlapped. That is, the control unit 6 can execute any combination of the first pattern control to the fifth pattern control.

Furthermore, the first formation and the second formation may be performed simultaneously (multi-focus processing) or sequentially (single-pass processing). That is, the control unit 6 may perform the second formation after the first formation, for example, in the first region A1 of the line A. Alternatively, the control unit 6 may display a modulation pattern including a branching pattern for branching the laser light L into the laser light L1 and L2 on the spatial light modulator 7 , so that the line set on the object 11 can be adjusted accordingly. For example, in the first region A1 of A, the first formation and the second formation are performed simultaneously.

Next, in the present embodiment, processing of the second portion 15B (see FIG. 31 ) of the object 11 is performed. In the second portion 15B, it is not necessary to form an oblique crack, but a vertical crack is formed here. Therefore, in the processing of the second portion 15B, the modified regions 12c and 12d and the cracks (vertical cracks) 13c and 13d extending from the modified regions 12c and 12d are formed by the same process as the above-mentioned trimming process (refer to Figure 45). In this case, in the second portion 15B, the first processing and the second processing are performed without switching the forward and reverse directions of the processing progress direction ND in the first area A1 and the second area A2.

However, in the above trimming process, in order to suppress deterioration of the quality of the trimmed surface, the beam shape is set to the first shape Q1 (first process) during the process of the first area A1, and the beam shape is set to the second shape during the process of the second area A2 Shape Q2 (second processing), but in the second portion 15B, the longitudinal direction NH of the light-condensing region C may be along the processing progress direction ND (not inclined with respect to the processing progress direction ND). The boundary between the first area A1 and the second area A2 is not turned ON/OFF of the irradiation of the laser light L, but the entire line A is continuously moved relative to the light-converging area C to form the modified areas 12c, 12d and the cracks 13c, 13d. That is, other processing different from the first processing and the second processing can also be performed in the second portion 15B. Alternatively, in the second part 15B, the switching of the machining progress direction ND may not be performed, and the 1st Z machining and the 2nd Z machining may be performed as another machining system. In the 1Z processing, the light-condensing region C is relatively moved along the first region A1 in the line A, thereby forming the modified regions 12c and 12d along the first region A1, and forming the modified regions 12c and 12d from the modified regions 12c and 12d. Cracks 13c, 13d extending in the Z direction; in the 2nd Z processing, the light-condensing region C is moved relatively along the second region A2 in the line A, thereby forming the modified region 12c along the second region A2, 12d, and cracks 13c, 13d extending from the modified regions 12c, 12d in the Z direction are formed. In this case, in the 1st Z processing and the 2 Z processing, similarly to the first processing and the second processing, it is possible to make the long side direction NH in the light condensing region C when viewed from the Z direction. The NH shapes the laser light L so that the direction close to the larger one of the first crystal orientation K1 and the second crystal orientation K2 with respect to the processing direction ND is inclined with respect to the processing direction ND.

By the above processing, as shown in FIGS. 44 and 45 , the modified region 12 and the crack 13 are formed in the object 11 in the entirety of the line A and substantially the entirety of the Z direction. In particular, as shown in FIG. 45 , cracks 13 a and 13 b are formed in the first portion 15A, and the cracks 13 a and 13 b are formed from the object 11 from the first surface 11 a toward the second surface 11 b of the object 11 . The position of the inner side of the junction region between the device layer 110 and the device layer 110R of the object 11R is inclined so as to face the outer edge 110e of the junction region. The cracks 13c and 13d may be discontinuous and separated, or they may be continuous. In addition, the fissure 13b and the fissure 13c may be discontinuous and separated, or may be continuous.

Next, a removal process is performed in the same manner as the above-mentioned trimming process. Specifically, the laser beam L is irradiated on the removal area E without rotating the stage 2 , and the irradiation unit 3 is moved in the X direction, so that the condensing area C of the laser beam L is relatively moved in the X direction with respect to the object 11 . . After the stage 2 is rotated by 90°, the removal area E is irradiated with laser light L, and the irradiation unit 3 is moved in the X direction, so that the condensing area C of the laser light L is relatively moved in the X direction with respect to the object 11 .

As a result, as shown in FIG. 46 , the modified region 12 and the cracks 13 extending from the modified region 12 are formed along a line extending so as to divide the removal region E into quarters when viewed from the Z direction. Then, as shown in FIG. 47( a ), the removal region E is removed with the modified region 12 as a boundary by, for example, a jig or a gas. Thereby, the semiconductor device 11K is formed from the object 11, and the object 100K including the semiconductor device 11K is obtained.

Next, the semiconductor device 11K is ground from the first surface 11a side. Here, the second portion 15B is removed, and a part of the first portion 15A is removed. The removed part of the first part 15A is a part where the modified regions 12a and 12b are formed. Therefore, the remaining portion of the first portion 15A does not include the modified regions 12a, 12b. When the object 11 is peeled off by etching, the polishing can be simplified. As a result of the above operations, the semiconductor device 11M is formed, and the object 100M including the semiconductor device 11M is obtained.

The laser processing of the present embodiment described above will be described in terms of the configuration of the laser processing apparatus 1 . That is, the laser processing apparatus 1 is used to irradiate the object 11 with the laser light L (laser light L1, L2) to form the modified region 12, and includes at least the stage 2 for supporting the object 11, Irradiation unit 3 for irradiating laser light L toward object 11 supported by stage 2 , moving unit 4 for relatively moving light-converging regions C (light-converging regions C1 , C2 ) of laser light L with respect to object 11 , 5, and the control part 6 for controlling the moving parts 4, 5 and the irradiation part 3. The irradiation unit 3 includes a spatial light modulator 7 that shapes the laser light L so that the light-converging region C has a longitudinal direction NH when viewed from the Z direction.

Then, the control unit 6 executes the first processing (the above-mentioned first processing), and in the first processing, the irradiation unit 3 and the moving units 4 and 5 are controlled so as to allow the light-converging area along the first area A1 in the line A C (light-condensing regions C1, C2) relatively moves, thereby forming modified regions 12 (modified regions 12a, 12b) in the object 11 along the first region A1, and forming the modified regions 12 toward the object The incident surface of 11, that is, the first surface 11a is the second surface 11b on the opposite side, and is an oblique crack 13F extending obliquely with respect to the Z direction.

Furthermore, the control unit 6 executes the second processing (the above-mentioned second processing), and in the second processing, the irradiation unit 3 and the moving units 4 and 5 are controlled to condense the light along the second area A2 in the line A. The region C (light-condensing regions C1, C2) is relatively moved, whereby the modified region 12 (modified region 12a, 12b) is formed in the object 11 along the second region A2, and the second surface from the modified region 12 is formed Oblique cracks 13F (cracks 13a, 13b) extending from 11b.

In the first processing and the second processing, the control unit 6 controls the spatial light modulator 7 so that the light-converging region C has the longitudinal direction NH when viewed from the Z direction, and the light-converging region C has a longitudinal direction NH. The longitudinal direction NH is inclined with respect to the machining advancement direction ND in the direction close to the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the moving direction of the light-converging region C, that is, the machining advancement direction ND way to shape the laser light L. In the first machining process and the second machining process, the control unit 6 controls the moving units 4 and 5 so that when viewed from the Z direction, the direction of the inclination of the longitudinal direction NH is the same as the direction of the machining progress direction ND. In such a manner that the extending directions of the fissures 13F are on the same side, the forward and reverse directions of the processing progress directions ND are switched between the first processing and the second processing.

Next, the laser processing of the present embodiment described above will be described in terms of steps of the laser processing method. That is, the laser processing method of the present embodiment is for irradiating the object 11 with the laser light L (laser light L1, L2) to form the modified region 12, and has a first processing step (the above-mentioned first processing) , in the first processing step, the condensing area C (condensing areas C1, C2) is relatively moved along the first area A1 set in the line A of the object 11, whereby the object is moved along the first area A1. The object 11 forms a modified region 12 (modified regions 12a, 12b), and a second surface 11b is formed from the modified region 12 toward the incident surface of the object 11, that is, on the opposite side of the first surface 11a, with respect to Z Oblique cracks 13F (cracks 13a, 13b) extending in an oblique direction.

Furthermore, the laser processing method of the present embodiment includes a second processing step (the above-mentioned second processing), and in the second processing step, the light-converging region C (light-converging region C1, C2) Relative movement, whereby the modified region 12 (modified regions 12a, 12b) is formed in the object 11 along the second region A2, and the oblique crack 13F extending from the modified region 12 toward the second surface 11b is formed (Cracks 13a, 13b).

In the first processing step and the second processing step, the long-side direction NH of the light-converging region C is made to be close to the first crystal orientation K1 and The laser beam L is shaped so that the direction of the larger angle between the second crystal orientation K2 and the moving direction of the light-converging region C, that is, the machining progress direction ND, is inclined with respect to the machining progress direction ND. Furthermore, in the first processing step and the second processing step, when viewed from the Z direction, the direction of the inclination of the longitudinal direction NH is on the same side as the extending direction of the diagonal crack 13F with respect to the processing progress direction ND. The forward and reverse of the machining progress direction ND is switched between the first machining process and the second machining process.

As described above, in the laser processing apparatus 1 and the laser processing method of the present embodiment, the object 11 has a crystal structure including a (100) plane, one (110) plane, and the other (110) plane plane, a first crystal orientation K1 orthogonal to one (110) plane, and a second crystal orientation K2 orthogonal to the other (110) plane. Here, in the case where the modified region 12 is formed in the object 11 along the first region A1 in the line A that relatively moves the condensing region C of the laser light L (first processing, first processing) , and in the case where the modified region 12 is formed in the object 11 along the second region A2 in the line A (second processing, second processing), the longitudinal direction NH of the light-condensing region C is made to be close to the second The laser beam L is shaped so that the orientation of the one of the first crystal orientation K1 and the second crystal orientation K2 with a larger angle with the processing progress direction ND is inclined with respect to the processing progress direction ND. Therefore, degradation of the quality of the trimmed surface can be suppressed.

On the other hand, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, in the first processing and the second processing (the first processing step and the second processing step are also the same (hereinafter the same)), Oblique cracks 13F extending obliquely with respect to the Z direction (direction intersecting the incident surface) from the modified region 12 toward the second surface 11b of the object 11 are formed. Therefore, the relationship between the extending direction of the oblique crack 13F and the orientation of the longitudinal direction NH of the light-converging region C must be considered. Furthermore, in the laser processing apparatus 1 and the laser processing method of the present embodiment, when viewed from the Z direction, the direction of the inclination of the longitudinal direction NH with respect to the processing progress direction ND is the extension side of the diagonal crack 13F. On the same side, the forward and reverse directions of the machining progress direction ND are switched between the first machining process and the second machining process.

As a result, in both the first area A1 and the second area A2, the direction of the inclination of the longitudinal direction NH of the light-converging area C with respect to the machining progress direction ND is made the same side as the extending side of the oblique crack 13F. In this way, the relationship between the direction of the longitudinal direction NH of the light condensing region C and the inclination direction of the oblique fissure 13F is a combination that can obtain relatively good quality, and can suppress the deterioration of the quality. As described above, according to the laser processing apparatus 1 and the laser processing method of the present embodiment, it is possible to form diagonal cracks in a state in which deterioration of the quality of the trimmed surface of the object 11 is suppressed.

In the laser processing apparatus 1 of the present embodiment, the object 11 may include a first portion 15A and a second portion 15B arranged in this order from the second surface 11b side along the Z direction. Then, the control unit 6 executes the first machining process and the second machining process by switching the forward and reverse directions of the machining progress direction ND for the first portion 15A, and executes the first machining process without switching the machining progress direction ND for the second portion 15B. In the processing and the second processing, a modified region 12 (modified regions 12c, 12d) and cracks 13 (cracks 13c, 13d) extending from the modified region 12 in the Z direction are formed in the second portion 15B. In this case, in the second portion 15B where the cracks 13 along the Z direction are formed, the forward and reverse switching of the machining progress direction ND is not performed between the first processing and the second processing. Therefore, the time associated with the acceleration and deceleration of the relative movement of the condensing region C of the laser light L can be reduced compared to the case of switching the forward and reverse directions of the machining progress direction ND in the first machining process and the second machining process.

Alternatively, in the laser processing apparatus 1 of the present embodiment, the control unit 6 may perform the first processing and the second processing by switching the processing progress direction ND between forward and reverse with respect to the first portion 15A, and for the second processing The portion 15B executes other processing (other processing) different from the first processing and the second processing. In other processing, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 so that the forward and reverse directions of the processing progress direction ND are the same for the entire line A, and the condensing area C is relatively moved along the line A, thereby moving along the line A. The contact line A forms a modified region 12 and a crack 13 extending in the Z direction from the modified region 12 in the object 11 . In this case, the relative movement to the condensing area C of the laser light L can be reduced compared to the case where the forward and reverse directions of the machining progress direction ND are also switched in the first area A1 and the second area A2 of the line A in the second portion 15B. The time related to the acceleration and deceleration.

Furthermore, in the laser processing apparatus 1 of the present embodiment, in another processing process, the control unit 6 may control the spatial light modulator 7 so that the light-converging region C has a longitudinal direction NH when viewed from the Z direction. The laser light L is shaped in such a manner that the longitudinal direction NH of the light-converging region C is aligned with the processing progress direction ND. In this case, compared to the formation of the second portion 15B of the crack 13 along the Z direction, the condensing region of the laser light L is set between the processing of the first area A1 of the line A and the processing of the second area A2 When the shaping of the laser beam L is performed in such a manner that the inclination of C changes, the processing of the control unit 6 can be simplified.

In addition, in the laser processing apparatus 1 of the present embodiment, the object 11 may include a joint region to be joined with another member (object 11R), and the control unit 6 may be formed in the first processing and the second processing. The oblique crack 13F is inclined so as to go from the position inside the joint region toward the outer edge 11e of the joint region as it goes from the first surface 11a to the second surface 11b. In this case, a part of the object 11 is removed from the object 11 with the oblique crack 13F as the boundary, and the remaining part of the object 11 is left, so as to avoid exceeding the joint area between the object 11 and other members. The remaining part of the object 11 is extended to the outside.

Furthermore, in the laser processing apparatus 1 of the present embodiment, the control unit 6 may execute the first forming process (the above-mentioned first forming process) and the second forming process (the above-mentioned second forming process) in the first processing process and the second processing process. forming), in the first forming process, the position of the light-condensing region C1 in the Z direction is set to the first Z-position Z1, and the light-converging region C1 is relatively moved along the line A, whereby the modified region 12a and the The cracks 13a extending from the modified region 12a are formed in the object 11; in the second forming process, the position of the light-condensing region C2 in the Z direction is set to the 2Z, which is closer to the first surface 11a than the 1Z position Z1 The modified region 12b and the crack 13b extending from the modified region 12b are formed by relatively moving the light-converging region C2 along the line A at the position Z2.

In the first forming process, the control unit 6 sets the position of the light-condensing region C1 in the Y direction intersecting the machining progress direction ND and the Z direction to the first Y position Y1, and in the second forming process, the control unit 6 sets the Y The position of the light condensing region C2 in the direction is set to the second Y position Y2 shifted from the first Y position Y1, and is controlled by the spatial light modulator 7 so that it is within the YZ plane S including the Y direction and the Z direction. The shape of the condensing region C2 is formed by shaping the laser light L2 in such a manner that the first surface 11a side is inclined toward the displacement direction at least from the center of the condensing region C2, and thereby the laser light L2 is formed in the YZ plane S toward the direction of the displacement. The crack 13b is formed so that the displacement direction is inclined. In this way, an oblique crack inclined with respect to the Z direction can be appropriately formed.

In the laser processing apparatus 1 of the present embodiment, the irradiation unit 3 may include a condenser lens 33 for condensing the laser light L from the spatial light modulator 7 toward the object 11 , and the second In the forming process, the control unit 6 controls the modulation pattern displayed on the spatial light modulator 7 to modulate the laser light L so that the shape of the condensing region C becomes an inclined shape, thereby shaping the laser light L. In this case, the laser light L can be easily shaped by the spatial light modulator 7 .

In this case, in the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a coma aberration pattern for imparting coma aberration to the laser light L, and in the second forming process, the control unit 6 uses the By controlling the magnitude of the coma aberration based on the coma aberration pattern, the first pattern control for making the shape of the light-converging region C into an oblique shape is performed. According to the knowledge of the present inventors, in this case, the shape of the condensing region C in the YZ plane S is formed in an arc shape. That is, in this case, the shape of the condensing area C is inclined in the displacement direction on the side of the first surface 11a (incident surface) from the center Ca of the condensing area C, The opposite side to the incident surface is inclined in the opposite direction to the displacement direction. Also in this case, an oblique crack 13F inclined in the displacement direction can be formed.

Furthermore, in the laser processing apparatus 1 of the present embodiment, the object 11 may include a first portion 15A and a second portion 15B arranged in this order from the second surface 11b side along the Z direction. Furthermore, the control unit 6 executes the 1Z machining process (the above-mentioned 1Z machining process) and the 2Z machining process (the above-mentioned 2Z machining process) as other machining processes, and in the 1Z machining process, for the first part 15A, the machining progresses The first processing and the second processing are performed by switching the forward and reverse directions of the direction ND, and the switching of the processing progress direction ND is not performed for the second part 15B. In the first area A1 of the target object 11, a modified area 12 is formed in the object 11 by relatively moving the light-converging area C, and a crack 13 extending from the modified area 12 in the Z direction is formed; In the second Z processing, by controlling the irradiation unit 3 and the moving units 4 and 5, the light-converging area C is relatively moved along the second area A2 in the line A, thereby forming a modified image on the object 11 along the second area A2. The modified region 12 is formed, and the crack 13 extending from the modified region 12 in the Z direction is formed. In this case, compared to the second portion 15B, the longitudinal direction NH of the light-converging region C is set in the first region A1 and the second region A2 according to the machining progress direction ND, and the first region A1 and the second region A1 In the case where the area A2 switches the forward and reverse directions of the machining progress direction ND, the time associated with the acceleration/deceleration of the relative movement of the laser light L and the condensing area C can be reduced.

In the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a spherical aberration correction pattern for correcting the spherical aberration of the laser light L, and in the second forming process, the control unit 6 may The center of the entrance pupil surface 33a of the optical lens 33 is offset in the Y direction by the center of the spherical aberration correction pattern Ps, whereby the second pattern control for making the shape of the light-converging region C be inclined is performed. According to the knowledge of the present inventors, also in this case, as in the case of using the coma aberration pattern, the shape of the condensing region C in the YZ plane S can be formed in an arc shape, and can be formed inclined in the displacement direction. The oblique crack 13F.

In the laser processing apparatus 1 of the present embodiment, in the second forming process, the control unit 6 may display on the spatial light modulator a modulation pattern that is asymmetrical with respect to the axis along the processing progress direction ND. 7. The third pattern control for making the shape of the light-converging region C into an oblique shape is performed. According to the knowledge of the present inventors, in this case, the shape of the light-condensing region C in the YZ plane S can be inclined as a whole in the displacement direction. Also in this case, an oblique crack 13F inclined in the displacement direction can be formed.

Furthermore, in the laser processing apparatus 1 of the present embodiment, the modulation pattern may include an ellipse pattern for making the shape of the light-condensing region C in the XY plane an ellipse with a long side in the X direction, and the XY plane may be Including the X direction and the Y direction intersecting the Y direction and the Z direction; in the second forming process, the control unit 6 displays the modulation pattern in such a manner that the intensity of the elliptical pattern becomes asymmetrical with respect to the axis along the X direction. The spatial light modulator 7 performs the fourth pattern control for making the beam shape into an oblique shape. According to the knowledge of the present inventors, also in this case, the shape of the condensing region C in the YZ plane S can be formed in an arc shape, and the oblique crack 13F inclined in the displacement direction can be formed.

Furthermore, in the laser processing apparatus 1 of the present embodiment, in the second forming process, the control unit 6 may allow the control unit 6 to form a converging point for a plurality of laser beams L aligned in the shift direction in the YZ plane S. The modulation pattern of CI is displayed on the spatial light modulator 7, whereby the fifth pattern control for making the shape of the light-condensing region C including the plurality of light-converging points CI to be inclined is performed. According to the knowledge of the present inventors, also in this case, an oblique crack 13F inclined in the displacement direction can be formed. [Second Embodiment of Laser Processing]

Next, another embodiment of laser processing for forming oblique cracks at the time of dressing processing will be described. FIG. 48 shows an object of laser processing according to an embodiment. As shown in FIG. 48 , the object of the laser processing of the present embodiment is the object 11 which is bonded to the object 11R to constitute the object 100 as in the first embodiment. However, in the present embodiment, the angular range of the first area A1 and the second area A2 in the line A is different from that of the first embodiment.

In the first embodiment, as an example, the boundary between the first area A1 and the second area A2 is set at a point of 45° or -45° at which quality degradation of the trimmed surface is likely to occur. This is based on the following understanding. That is, in the first embodiment, even at the points of 45° and -45°, where quality degradation is likely to occur, as long as the forward and reverse directions of the processing progress direction ND are adjusted, the processing at the points of 45° and -45° is relative to the processing progress. In the direction ND, the direction of the inclination of the longitudinal direction NH of the light-converging region C and the extending direction of the oblique fissure 13F are on the same side, so that deterioration in quality can be suppressed.

On the other hand, as shown in the table of FIG. 38 , for example, when the machining progress direction ND when machining the first area A1 and the second area A2 is both the forward direction ND1 (refer to the first and second from the top). Table 3), at -45°, when the beam shape of the condensing region C is set to the first shape Q1 (refer to the third table from the top), the quality is degraded, but when the beam shape is set to the second shape Q2 (refer to the first table from the top), good quality can be obtained, and even at -50° point, good quality can be obtained.

Therefore, even if the processing progress direction ND during processing of the first area A1 and the second area A2 is unified as the forward direction ND1, as long as the beam shape of the condensing area C is set during processing in the angular range of 0° to -50° It is the second shape Q2, and the beam shape of the condensing area C is set to the first shape Q1 during processing in the angular range of -50° to -90°, so that good processing quality can be obtained in the entire angular range. . In fact, referring to the table of FIG. 49 , it can be seen that by using the condition IR7 and the condition IR8 in combination, good processing quality can be obtained in the entire angle range.

Furthermore, for example, when the machining progress direction ND when machining the first area A1 and the second area A2 is both the reverse direction ND2 (refer to the second and fourth tables from the top), at -45° In contrast to the example in the forward direction D1, when the beam shape of the condensing region C is set to the second shape Q2 (refer to the second table from the top), the quality is degraded, but when the first shape Q1 is set (Refer to the 4th table from the top) Good quality can be obtained, and good quality can be obtained even at the -40° point.

Therefore, even if the machining progress direction ND during machining of the first area A1 and the second area A2 is unified as the reverse direction ND2, the beam shape of the condensing area C is set as In the second shape Q2, when machining in an angle range of about -40° to -90°, the beam shape of the condensing region C is set to the first shape Q1, so that good machining quality can be obtained in the entire angle range. Actually, referring to the table of FIG. 50 , it can be seen that by using the condition IR9 and the condition IR10 in combination, good processing quality can be obtained in the entire angle range.

That is, the longitudinal direction NH of the light-condensing region C is inclined with respect to the machining advancement direction ND in the direction close to the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the machining advancement direction ND. The laser beam L is shaped in such a way that the forward and reverse directions of the processing progress directions are set to be the same in the processing of the first area A1 (the above-mentioned first processing) and the processing of the second area A2 (the above-mentioned second processing). In the first area A1 and the second area A2, as long as the direction of the inclination of the longitudinal direction NH is the same side as the extension side of the diagonal crack 13F with respect to the machining progress direction ND, the 45° point is included. By setting the boundary between the first area A1 and the second area A2 according to the method (the above example is the -45° point), good processing quality can be obtained in the entire angle range.

The laser processing of this embodiment is performed based on the above knowledge. That is, in the laser processing of the present embodiment, as shown in FIG. 48 , the boundary Ks of the first area A1 and the second area A2 is set so that the direction of the inclination of the longitudinal direction NH with respect to the processing progress direction ND is The 45° point (-45° point in the above example) is included in the same side as the extension side of the oblique crack 13F. In the example shown in the figure, the machining progress direction ND is set to the forward direction ND1, and the boundary Ks is set so that the second area A2 includes the 45° point.

In particular, compared with the first embodiment, the first area A1 is reduced by about 5° and becomes an arc of about 40°, which is about 0° to 40°, and the second area A2 is enlarged by about 5°. Since it becomes an arc of about 50° component of about 40° to 90°, the second area A2 is longer than the first area A1 by about 10° component. The processing of each of the first area A1 and the second area A2 is the same as the above-mentioned first processing and second processing (further the first forming and 2 Forming) is implemented in the same way.

The laser processing of the present embodiment described above will be described in terms of the configuration of the laser processing apparatus 1 . That is, the laser processing apparatus 1 is used to irradiate the object 11 with the laser light L (laser light L1, L2) to form the modified region 12, and includes at least the stage 2 for supporting the object 11, Irradiation unit 3 for irradiating laser light L toward object 11 supported by stage 2 , moving unit 4 for relatively moving light-converging regions C (light-converging regions C1 , C2 ) of laser light L with respect to object 11 , 5, and the control part 6 for controlling the moving parts 4, 5 and the irradiation part 3. The irradiation unit 3 includes a spatial light modulator 7 that shapes the laser light L so that the light-converging region C has a longitudinal direction NH when viewed from the Z direction.

Then, the control unit 6 executes the first processing (the above-mentioned first processing), and in the first processing, the irradiation unit 3 and the moving units 4 and 5 are controlled so as to allow the light-converging area along the first area A1 in the line A C (light-condensing regions C1, C2) relatively moves, thereby forming modified regions 12 (modified regions 12a, 12b) in the object 11 along the first region A1, and forming the modified regions 12 toward the object The incident surface of 11, that is, the first surface 11a is the second surface 11b on the opposite side, and is an oblique crack 13F (cracks 13a, 13b) extending obliquely with respect to the Z direction.

Furthermore, the control unit 6 executes the second processing (the above-mentioned second processing), and in the second processing, the irradiation unit 3 and the moving units 4 and 5 are controlled to condense the light along the second area A2 in the line A. The region C (light-condensing regions C1, C2) is relatively moved, whereby the modified region 12 (modified region 12a, 12b) is formed in the object 11 along the second region A2, and the second surface from the modified region 12 is formed Oblique cracks 13F (cracks 13a, 13b) extending from 11b.

In the first processing and the second processing, the control unit 6 controls the spatial light modulator 7 so that the longitudinal direction NH of the light-condensing region C is close to the convergence between the first crystal orientation K1 and the second crystal orientation K2 The moving direction of the light region C, that is, the direction of the larger angle between the machining progress directions ND is inclined with respect to the machining progress direction ND, and the laser light L is shaped so that the first machining process and the second machining process are performed. The forward and reverse directions of the machining progress direction ND are set to be the same.

Furthermore, the point where the second crystal orientation K2 and the line A are orthogonal is set to 0°, the point where the first crystal orientation K1 and the line A are orthogonal is set to 90°, and the point between 0° and 90° on the line A is set. When the intermediate point is set to 45°, the first area A1 and the second area A2, when viewed from the Z direction, are inclined in the direction of the longitudinal direction NH relative to the machining progress direction ND and the oblique crack 13F. The boundary Ks of the first area A1 and the second area A2 is set so that the one where the extension side becomes the same side includes the 45° point.

Next, the laser processing of the present embodiment described above will be described in terms of steps of the laser processing method. That is, the laser processing method of the present embodiment is for irradiating the object 11 with the laser light L (laser light L1, L2) to form the modified region 12, and has a first processing step (the above-mentioned first processing) , in the first processing step, the condensing area C (condensing areas C1, C2) is relatively moved along the first area A1 set in the line A of the object 11, whereby the object is moved along the first area A1. The object 11 forms a modified region 12 (modified regions 12a, 12b), and a second surface 11b is formed from the modified region 12 toward the incident surface of the object 11, that is, on the opposite side of the first surface 11a, with respect to Z Oblique cracks 13F (cracks 13a, 13b) extending in an oblique direction.

Furthermore, the laser processing method of the present embodiment includes a second processing step (the above-mentioned second processing), and in the second processing step, the light-converging region C (light-converging region C1, C2) Relative movement, whereby the modified region 12 (modified regions 12a, 12b) is formed in the object 11 along the second region A2, and the oblique crack 13F extending from the modified region 12 toward the second surface 11b is formed (Cracks 13a, 13b).

In the first processing step and the second processing step, the long-side direction NH of the light-converging region C is made to be close to the first crystal orientation K1 and The laser beam L is shaped so that the direction of the larger angle between the second crystal orientation K2 and the moving direction of the light-converging region C, that is, the machining progress direction ND, is inclined with respect to the machining progress direction ND, and the first In the processing step and the second processing step, the forward and reverse directions of the processing progress direction ND are the same.

Furthermore, the point where the second crystal orientation K2 and the line A are orthogonal is set to 0°, the point where the first crystal orientation K1 and the line A are orthogonal is set to 90°, and the point between 0° and 90° on the line A is set. When the middle point is set to 45°, in the first area A1 and the second area A2, when viewed from the Z direction, the direction of the inclination of the longitudinal direction NH is relative to the machining progress direction ND and the oblique crack 13F. The boundary Ks of the first area A1 and the second area A2 is set so that the extension side of the same side includes the 45° point.

As described above, in the laser processing apparatus 1 and the laser processing method of the present embodiment, the object 11 has a crystal structure including a (100) plane, one (110) plane, and the other (110) plane plane, a first crystal orientation K1 orthogonal to one (110) plane, and a second crystal orientation K2 orthogonal to the other (110) plane. Here, in the case where the modified region 12 is formed in the object 11 along the first region A1 in the line A that relatively moves the condensing region C of the laser light L (first processing, first processing) , and in the case where the modified region 12 is formed in the object 11 along the second region A2 in the line A (second processing, second processing), the longitudinal direction NH of the light-condensing region C is made to be close to the second The laser beam L is shaped so that the orientation of the one of the first crystal orientation K1 and the second crystal orientation K2 with a larger angle with the processing progress direction ND is inclined with respect to the processing progress direction ND. Therefore, as shown by the above-mentioned knowledge, the quality degradation of the trimmed surface can be suppressed.

On the other hand, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, in the first processing and the second processing (the first processing step and the second processing step are also the same (hereinafter the same)), The second surface 11b (opposite surface) opposite to the first surface 11a (incident surface) of the object 11 from the modified region 12 is formed in an oblique direction extending obliquely with respect to the Z direction (direction intersecting the incident surface) Cracked 13F. Therefore, the relationship between the extending direction of the oblique crack 13F and the orientation of the longitudinal direction NH of the light-converging region C must be considered. In particular, during processing at a 45° point, if the direction of the long-side direction NH of the light-converging region C and the inclination direction of the oblique crack 13F are opposite to each other with respect to the processing progress direction ND, the trimming surface is likely to be damaged. Quality is reduced.

On the other hand, in the laser processing apparatus 1 and the laser processing method of the present embodiment, the boundary Ks between the first area A1 and the second area A2 is set such that the length of the first area A1 and the second area A2 is The direction of the inclination of the side direction NH with respect to the machining progress direction ND is the same side as the extension side of the oblique crack 13F, including the 45° point. In other words, in the first area A1 and the second area A2, the processing is performed in a state where the direction of the longitudinal direction NH of the light-converging area C and the inclination direction of the oblique crack 13F are opposite to each other with respect to the processing progress direction ND. area without reaching the 45° point on line A. Therefore, quality degradation can be suppressed. As described above, according to the laser processing apparatus 1 and the laser processing method of the present embodiment, the oblique cracks 13F can be formed in a state where deterioration of the quality of the trimmed surface of the object 11 is suppressed.

In addition, in the laser processing apparatus 1 and the laser processing method of this embodiment, the forward and reverse directions of the processing progress direction ND are the same in the first processing and the second processing. Therefore, the time associated with the acceleration and deceleration of the relative movement of the condensing region C of the laser light L can be reduced compared to the case of switching the forward and reverse directions of the machining progress direction ND in the first machining process and the second machining process.

Furthermore, in the laser processing apparatus 1 of the present embodiment, in the first area A1 and the second area A2, when viewed from the Z direction, the direction of the inclination of the longitudinal direction NH with respect to the processing progress direction ND may be equal to One of the extending sides of the oblique crack 13F is longer than the other. In this way, the lengths of the first area A1 and the second area A2 can be set to be different.

In the laser processing apparatus 1 of the present embodiment, the control unit 6 may execute the first processing and the second processing by setting the forward and reverse directions of the processing progress direction ND to be the same for the first portion 15A, and for the second processing. The portion 15B executes other processing (other processing) different from the first processing and the second processing. In the other processing, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 so that the forward and reverse directions of the processing progress direction ND are the same for the entire line A, and the light-converging area C is relatively moved along the line A, thereby moving along the line A. The contact line A forms a modified region 12 and a crack 13 extending in the Z direction from the modified region 12 in the object 11 . In this case, the relative movement to the condensing area C of the laser light L can be reduced compared to the case where the forward and reverse directions of the machining progress direction ND are also switched in the first area A1 and the second area A2 of the line A in the second portion 15B. The time related to the acceleration and deceleration.

Furthermore, in the laser processing apparatus 1 of the present embodiment, in another processing process, the control unit 6 may control the spatial light modulator 7 so that the light-converging region C has a longitudinal direction NH when viewed from the Z direction. The laser light L is shaped in such a manner that the longitudinal direction NH of the light-converging region C is aligned with the processing progress direction ND. In this case, compared to the formation of the second portion 15B of the crack 13 along the Z direction, the condensing region of the laser light L is set between the processing of the first area A1 of the line A and the processing of the second area A2 When the shaping of the laser beam L is performed in such a manner that the inclination of C changes, the processing of the control unit 6 can be simplified.

In addition, the laser processing apparatus 1 of the present embodiment may perform the 1Z processing (the above-mentioned 1Z processing) and the 2Z processing (the above-mentioned 2Z processing) as other processing processing, and in the 1Z processing processing, for the first Z processing. The second part 15B does not switch the machining progress direction ND, and controls the irradiation part 3 and the moving parts 4 and 5 to relatively move the condensing area C along the first area A1 in the line A, thereby moving along the first area A1. In the region A1, a modified region 12 is formed in the object 11, and a crack 13 extending from the modified region 12 in the Z direction is formed; in the second Z processing, by controlling the irradiation part 3 and the moving parts 4, 5, the A modified region 12 is formed on the object 11 along the second region A2 by moving the condensing region C relative to the second region A2 in the line A, and a tortoise extending from the modified region 12 in the Z direction is formed. Crack 13. In this case, compared to the second portion 15B, the longitudinal direction NH of the light-converging region C is set in the first region A1 and the second region A2 according to the machining progress direction ND, and the first region A1 and the second region A1 In the case where the area A2 switches the forward and reverse directions of the machining progress direction ND, the time associated with the acceleration/deceleration of the relative movement of the laser light L and the condensing area C can be reduced.

In the laser processing apparatus 1 of the present embodiment, the object 11 may include a joint region to be joined with another member (object 11R), and the control unit 6 may be formed so as to follow the first processing and the second processing. An oblique crack 13F inclined so as to go from the first surface 11a to the second surface 11b and from a position inside the joint region to the outer edge 11e of the joint region. In this case, a part of the object 11 is removed from the object 11 with the oblique crack 13F as the boundary, and the remaining part of the object 11 is left, so as to avoid exceeding the joint area between the object 11 and other members. The remaining part of the object 11 is extended to the outside.

In the laser processing apparatus 1 of the present embodiment, the control unit 6 may execute the first forming process (the above-mentioned first forming process) and the second forming process (the above-mentioned second forming process) in the first processing process and the second processing process. ), in the first forming process, the position of the light condensing region C1 in the Z direction is set to the first Z position Z1, and the light condensing region C1 is relatively moved along the line A, thereby forming the modified region 12a and the modified region 12a from the modified region 12a. The crack 13a extending from the qualitative region 12a is formed in the object 11; in the second forming process, the position of the light-condensing region C2 in the Z direction is set to the 2Z position on the side of the first surface 11a rather than the 1Z position Z1 Z2, and relatively moving the condensing region C2 along the line A, thereby forming the modified region 12b and the crack 13b extending from the modified region 12b.

In the first forming process, the control unit 6 sets the position of the light-condensing region C1 in the Y direction intersecting the machining progress direction ND and the Z direction to the first Y position Y1, and in the second forming process, the control unit 6 sets the Y The position of the light condensing region C2 in the direction is set to the second Y position Y2 shifted from the first Y position Y1, and is controlled by the spatial light modulator 7 so that it is within the YZ plane S including the Y direction and the Z direction. The shape of the condensing region C2 is formed by shaping the laser light L2 in such a manner that the first surface 11a side is inclined toward the displacement direction at least from the center of the condensing region C2, and thereby the laser light L2 is formed in the YZ plane S toward the direction of the displacement. The oblique crack 13F is formed so that the displacement direction is inclined. In this way, an oblique crack inclined with respect to the Z direction can be appropriately formed.

In the laser processing apparatus 1 of the present embodiment, the irradiation unit 3 may include a condenser lens 33 for condensing the laser light L from the spatial light modulator 7 toward the object 11 , and the second formed In the process, the control unit 6 controls the modulation pattern displayed on the spatial light modulator 7 to modulate the laser light L so that the shape of the light-converging region C becomes an oblique shape, thereby shaping the laser light L. In this case, the laser light L can be easily shaped by the spatial light modulator 7 .

In this case, in the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a coma aberration pattern for imparting coma aberration to the laser light L, and in the second forming process, the control unit 6 uses the By controlling the magnitude of the coma aberration based on the coma aberration pattern, the first pattern control for making the shape of the light-converging region C into an oblique shape is performed. According to the knowledge of the present inventors, in this case, the shape of the condensing region C in the YZ plane S is formed in an arc shape. That is, in this case, the shape of the condensing area C is inclined in the displacement direction on the side of the first surface 11a (incident surface) from the center Ca of the condensing area C, The opposite side to the incident surface is inclined in the opposite direction to the displacement direction. Also in this case, an oblique crack 13F inclined in the displacement direction can be formed.

In the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a spherical aberration correction pattern for correcting spherical aberration of the laser light L, and in the second forming process, the control unit 6 may The center of the entrance pupil surface 33a of the lens 33 is offset in the Y direction from the center of the spherical aberration correction pattern Ps, whereby the second pattern control for making the shape of the light-converging region C be inclined is performed. According to the knowledge of the present inventors, also in this case, as in the case of using the coma aberration pattern, the shape of the condensing region C in the YZ plane S can be formed into an arc shape, and can be formed to be inclined in the displacement direction. The oblique crack 13F.

In the laser processing apparatus 1 of the present embodiment, in the second forming process, the control unit 6 may display on the spatial light modulator 7 an asymmetric modulation pattern with respect to the axis along the processing progress direction ND , and the third pattern control for making the shape of the light-converging region C to be an inclined shape is performed. According to the knowledge of the present inventors, in this case, the shape of the light-condensing region C in the YZ plane S can be inclined as a whole in the displacement direction. Also in this case, an oblique crack 13F inclined in the displacement direction can be formed.

In the laser processing apparatus 1 of the present embodiment, the modulation pattern may include an elliptical pattern for making the shape of the light-condensing region C in the XY plane an ellipse with a long side in the X direction, and the XY plane may include The X direction and the Y direction intersecting the Y direction and the Z direction; in the second forming process, the control unit 6 displays the modulation pattern in space so that the intensity of the elliptical pattern becomes asymmetrical with respect to the axis along the X direction The light modulator 7 performs the fourth pattern control for making the beam shape into an oblique shape. According to the knowledge of the present inventors, also in this case, the shape of the condensing region C in the YZ plane S can be formed in an arc shape, and the oblique crack 13F inclined in the displacement direction can be formed.

In the laser processing apparatus 1 of the present embodiment, in the second forming process, the control unit 6 may cause the converging point CI for forming a plurality of laser beams L arranged in the displacement direction in the YZ plane S The modulation pattern is displayed on the spatial light modulator 7, whereby the fifth pattern control for making the shape of the light-condensing region C including the plurality of light-converging points CI into an oblique shape is performed. According to the knowledge of the present inventors, also in this case, an oblique crack 13F inclined in the displacement direction can be formed. [Variation]

One aspect of the laser processing apparatus and the laser processing method has been described above, but one aspect of the present invention is not limited to the above aspect, and can be deformed.

For example, in the above-mentioned example, the object 100 (bonded wafer) composed of the object 11 and the object 11R bonded together is described, but the object of laser processing is not limited to such a bonded wafer, but also An object such as a single wafer may be used.

Also, in the example shown in FIG. 45 , the case where the two modified regions 12 a and 12 b are formed by using the two light condensing regions C1 and C2 for the first portion 15A is exemplified. In this case, when the oblique crack 13F is formed, the beam shape is controlled at least in the YZ plane S of the condensing region C2 on the side of the first plane 11a. However, in the case of forming a plurality of modified regions 12a, 12b in the first portion 15A, when forming the modified regions 12a, 12b closest to the second surface 11b side (object 11R side), it is only necessary to control at least The beam shape in the YZ plane S of the condensing region C2 on the side of the first surface 11a may be more.

Also in the above-described embodiment, vertical cracks are formed in the second portion 15B of the object 11 . However, also about the 2nd part 15B of the object 11, the diagonal crack may be formed similarly to the 1st part 15A.

In the example described in the laser processing of the first embodiment, the processing of the first area A1 in the line A, that is, the processing of the first processing and the processing of the second area A2, that is, the processing of the second processing image 0° and 45°. , 90° and 45° intervals are set on the GUI, and the actual laser ON/OFF is also performed at that angle. However, in an actual device, there may be a delay of several hundred msec from the setting due to the delay of the laser ON/OFF. That is, it is not limited to the case where ON/OFF of the laser is strictly performed at the boundary between the first area A1 and the second area A2.

For the reasons described above, in order to reduce the amount of deviation in the formation position of the modified region 12 , the control unit 6 may also have a correction parameter for pre-correcting the delay time of laser ON/OFF to advance the laser ON/OFF. In this case, the variation in the formation positions of the modified regions 12 can be suppressed within 1 mm. As an example, when the object 11 is a 12-inch wafer, the circumference is about 942 mm, and every 1° is about 2.617 mm, so the variation in this case can be suppressed within 1°.

Also, as shown in the results of FIG. 38 and the like, it can be confirmed that there is a processing quality margin of about ±5° at the switching point between the first area A1 and the second area A2. Therefore, as long as it is within the quality margin, the setting of the switching point can be deliberately shifted, such as 0˚±5˚, 45˚±5˚, and 90˚±5˚.

In the above-mentioned embodiment, for example, the modified region 12 is formed so as to be annular when viewed from the Z direction by turning on and off the laser, but strictly speaking, it may be locally turned on and off at the position that is turned on and off. When the modified regions 12 (for example, about several hundreds of μm) are overlapped, or on the contrary, there are regions where the modified regions 12 are not formed locally (for example, about several hundreds of μm). In order to avoid the deterioration of quality due to the influence of the above, there are cases where multi-stage processing is used, and the plurality of stages are processed so that the formation of diagonal cracks and the above-mentioned effects of the first processing and the second processing are performed.

In actual processing, the run-up distance is necessary until the relative movement speed of the light-converging region C becomes constant, so the switching of the forward direction ND1 and the reverse direction ND2 includes the run-up. Turn off the laser during the run-up, and turn on the laser at the switching point when the speed becomes constant. The speed of the approach depends on the performance of the device. As for the autofocus, it is adjusted so as to avoid overshoot when the modified area is formed by tracking from the start-up time.

Furthermore, in the second embodiment, the switching accuracy is the same as the above-mentioned example, but as switching points such as the 45° point and the 135° point, as shown in the table in Fig. 49, at -45° At least the point is not switched, but is switched around the -50° point (in the example of the table in Figure 50, the switch is performed around the -40° point). In this case, the allowable margin of deviation is, for example, about ±2°, and may be increased to about ±4°, for example, depending on the beam shape (the ellipticity is further increased). On the other hand, it is not necessary to stagger the switching points of 0° and 90°, but it may be staggered within the range of ±4°, for example, according to the margin of quality. [Industrial Utilization Possibility]

Provided are a laser processing apparatus and a laser processing method capable of forming an oblique crack while suppressing deterioration of the quality of the trimmed surface of the object after the outer edge portion has been removed.

1: Laser processing device 2: stage (support part) 3: Irradiation part 4,5: Mobile Department 6: Control Department 7: Spatial light modulator 11: Object 11a: 1st side (incidence side) 11b: side 2 (opposite side) 12, 12a, 12b: Modified region 13, 13a, 13b: Cracks 13F: Oblique crack 33: Condenser lens A1: Area 1 A2: Area 2 K1: The first crystal orientation K2: The second crystal orientation L: laser light C, C1, C2: Concentrating area ND: Processing progress direction

FIG. 1 is a schematic diagram showing the configuration of a laser processing apparatus according to an embodiment. FIG. 2 is a schematic diagram showing the configuration of the laser irradiation section shown in FIG. 1 . [Fig. 3] shows the 4f lens unit shown in Fig. 2. [Fig. [Fig. 4] shows the spatial light modulator shown in Fig. 2. [Fig. [Fig. 5] (a), (b) are cross-sectional views of the object for explaining the recognition of the formation of the oblique crack. Fig. 6 is a cross-sectional view of an object for explaining the recognition of oblique crack formation. [Fig. 7] shows the beam shape of the condensing region of the laser light. [Fig. 8] shows the bias of the modulation pattern. [Fig. 9] (a), (b) are cross-sectional photographs showing the formation state of the oblique crack. [ Fig. 10 ] A schematic plan view of an object. [Fig. 11] (a), (b) are cross-sectional photographs showing the formation state of the oblique cracks. [Fig. 12] (a), (b) are cross-sectional photographs showing the formation state of the oblique crack. [Fig. 13] (a) and (b) show examples of modulation patterns. [Fig. 14] (a) and (b) show the intensity distribution at the entrance pupil plane of the condenser lens and the beam shape in the condensing area. [Fig. 15] (a) and (b) show the observation results of the beam shape of the condensing area and the intensity distribution of the condensing area. [Fig. 16] (a), (b), and (c) show examples of modulation patterns. [Fig. 17] (a), (b), (c) show other examples of asymmetric modulation patterns. [Fig. 18] (a) and (b) show the intensity distribution at the entrance pupil plane of the condenser lens and the beam shape in the condensing area. FIG. 19 shows an example of a modulation pattern and the formation of a light condensing area. [ Fig. 20 ] The object to be processed is shown. [Fig. 21] (a) and (b) show the processed objects. [Fig. 22] (a), (b), (c) are schematic diagrams showing the shape of the beam in the condensing area. [Fig. 23] (a), (b), (c) are schematic diagrams showing the beam shape of the light-converging region. [ Fig. 24 ] (a), (b), and (c) show one step of the trimming process. [Fig. 25] (a) and (b) show one step of the trimming process. [ Fig. 26 ] (a), (b), and (c) show one step of the trimming process. [ Fig. 27 ] A step of the trimming process is shown. [Fig. 28] (a) and (b) show one step of the trimming process. [ Fig. 29 ] (a) and (b) show one step of the trimming process. [Fig. 30] (a) and (b) show the object of laser processing according to one embodiment. Fig. 31 is a cross-sectional view of the object shown in Fig. 30 . [FIG. 32] It is a top view of the object shown in FIG. 30. [FIG. [Fig. 33] (a), (b), (c), and (d) are cross-sectional photographs showing processing results. [Fig. 34] (a), (b), (c), and (d) are cross-sectional photographs showing processing results. [ Fig. 35 ] A schematic diagram for explaining the display processing test. [ Fig. 36 ] (a) and (b) are schematic diagrams showing the relationship between the direction of progress of processing and the shape of the beam and the oblique crack in the processing test. Fig. 37 is a table showing the results of the processing tests shown in Figs. 35 and 36 . [Fig. 38] is a table showing the results of the processing test. [Fig. 39] (a), (b), (c), (d), and (e) are cross-sectional photographs showing the results of processing tests. [ Fig. 40 ] (a) and (b) show one step of laser processing in one embodiment. [ Fig. 41 ] (a) and (b) show one step of laser processing in one embodiment. [ Fig. 42 ] (a) and (b) show one step of laser processing in one embodiment. [ Fig. 43 ] (a) and (b) show one step of laser processing in one embodiment. [ Fig. 44 ] (a) and (b) show one step of laser processing in one embodiment. FIG. 45 shows one step of laser processing in one embodiment. [ Fig. 46 ] (a) and (b) show one step of laser processing in one embodiment. [ Fig. 47 ] (a) and (b) show one step of laser processing in one embodiment. Fig. 48 shows an object of laser processing according to an embodiment. [ Fig. 49 ] A table showing the results of the processing test. [ Fig. 50 ] is a table showing the results of processing tests.

11: Object

A: Line

A1: Area 1

A2: Area 2

C: Concentrating area

CD: the extension direction of the oblique crack

CD2: reverse direction

E: remove area

K1: The first crystal orientation

K2: The second crystal orientation

K3: The third crystal orientation

K4: 4th crystal orientation

ND: Processing progress direction

ND2: reverse direction

NH: Long side direction

R: effective area

Q1: 1st shape

α: Machining angle

β: Beam angle

Claims (13)

A laser processing device, which is used for irradiating a laser light on an object to form a modified region, It is provided with: a support part for supporting the object; an irradiation part for irradiating the laser light toward the object supported by the support part; a moving part for moving, and a control part for controlling the moving part and the irradiation part; The object has a crystal structure including a (100) plane, one (110) plane, the other (110) plane, a first crystal orientation orthogonal to the one (110) plane, and the other (110) plane. (110) a second crystal orientation orthogonal to the plane, and the object is supported by the support portion so that the (100) plane becomes the incident surface of the laser light; The object is set as an annular line when viewed from the Z direction intersecting the incident surface, the line including an arc-shaped first area and an arc-shaped area having a boundary with the first area Zone 2; The irradiation part has a shaping part, and the shaping part shapes the laser light in such a way that the light-converging region has a longitudinal direction when viewed from the Z direction; The control unit executes the first processing and the second processing, In the first processing, by controlling the irradiation unit and the moving unit, the light-converging area is relatively moved along the first area in the line, whereby the object is formed along the first area on the object. A modified region, and an oblique crack extending obliquely with respect to the Z direction is formed from the modified region toward the opposite surface opposite to the incident surface of the object; In the second processing, by controlling the irradiation unit and the moving unit, the light-converging area is relatively moved along the second area in the line, whereby the object is formed along the second area on the object. A modified region, and the aforementioned oblique crack extending from the aforementioned modified region toward the aforementioned opposite surface is formed; In the first processing and the second processing, the control section controls the forming section so that the longitudinal direction of the light-condensing region is close to the first crystal orientation and the second crystal orientation and the The moving direction of the light-converging region, that is, the direction of the larger angle between the processing progress directions is inclined with respect to the processing progress direction, the laser beam is shaped, and the moving part is controlled to perform the first processing in the first processing. The processing and the second processing processing make the forward and reverse directions of the processing progress direction the same; When the point at which the second crystal orientation and the line are orthogonal is set as 0°, the point at which the first crystal orientation and the line are orthogonal is set at 90°, and the midway between the 0° and the 90° on the line is set When the point is set to 45°, in the first area and the second area, when viewed from the Z direction, the direction of the inclination of the longitudinal direction is the same as the diagonal crack with respect to the processing progress direction. The boundary between the first region and the second region is set in such a manner that one of the extending sides is the same side and includes the 45° point. The laser processing apparatus according to claim 1, wherein, The one of the first region and the second region is longer than the other of the first region and the second region. The laser processing apparatus according to claim 1 or 2, wherein, The object system includes: a first part and a second part arranged in order from the opposite surface side along the Z direction, The control unit executes the first machining process and the second machining process by setting the forward and reverse directions of the machining progress direction to be the same for the first part, and executes the first machining process and the second machining process for the second part. Processing other than the second processing mentioned above, In the above-mentioned other processing, the control unit controls the irradiation unit and the moving unit so that the forward and reverse directions of the processing progress direction are the same over the entire line, and the light-converging area is relatively moved along the line. The modified region and the crack extending in the Z direction from the modified region are formed in the object along the line. The laser processing apparatus according to claim 3, wherein, In the said other processing, the said control part controls the said shaping|molding part, and shapes the said laser light so that the said longitudinal direction of the said light-condensing area may be along the said processing progress direction. The laser processing apparatus according to any one of claims 1 to 4, wherein, The aforementioned object includes a joint region that is joined to other components, In the first processing and the second processing, the control unit forms the oblique tortoise that is inclined from the inner side of the joint region toward the outer edge of the joint region as it goes from the incident surface to the opposite surface. crack. The laser processing apparatus according to any one of claims 1 to 5, wherein, In the first processing and the second processing, the control unit executes the first forming processing and the second forming processing, In the first forming process, the position of the light-converging region in the Z direction is set to the 1Z position, and the light-converging region is relatively moved along the line, thereby forming the first modified region as the modified region. The modified region and the cracks extending from the first modified region are formed in the object, In the second forming process, the position of the light condensing region in the Z direction is set to a 2Z position on the incident surface side relative to the 1Z position, and the light condensing region is relatively moved along the line, Thereby, the second modified region as the modified region and the crack extending from the second modified region are formed, In the first forming process, the control unit sets the position of the light-converging region in the Y direction intersecting the processing progress direction and the Z direction as the first Y position, In the second forming process, the control unit sets the position of the light-converging region in the Y direction to the second Y position shifted from the first Y position, and controls the forming unit to set the position including the The shape of the condensing region in the YZ plane in the Y direction and the Z direction is such that the laser light is slanted in the direction of the displacement at least on the incident surface side from the center of the light condensing region. By molding, the oblique crack is formed in the YZ plane so as to be inclined in the direction of the displacement. The laser processing apparatus according to claim 6, wherein, The shaping part includes: a spatial light modulator for shaping the laser light by modulating the laser light according to a modulation pattern, The irradiation unit includes: a condenser lens for condensing the laser light from the spatial light modulator toward the object, In the second forming process, the control unit controls the modulation pattern displayed on the spatial light modulator to modulate the laser light so that the shape of the light-converging region becomes the inclined shape, thereby changing the The aforementioned laser light shaping. The laser processing apparatus according to claim 7, wherein, The aforementioned modulation pattern includes a coma aberration pattern for imparting coma aberration to the aforementioned laser light, In the second forming process, the control unit controls the magnitude of the coma aberration based on the coma aberration pattern, thereby performing the first pattern control for changing the shape of the light-converging region into the oblique shape. The laser processing apparatus according to claim 7 or 8, wherein, The modulation pattern includes a spherical aberration correction pattern for correcting the spherical aberration of the laser light, In the second forming process, the control unit performs a process for shifting the light-converging region by offsetting the center of the spherical aberration correction pattern in the Y direction with respect to the center of the entrance pupil surface of the condenser lens. The shape becomes the second pattern control of the aforementioned inclined shape. The laser processing apparatus according to any one of claims 7 to 9, wherein, In the second forming process, the control unit performs the control for causing the light condensing region to display on the spatial light modulator the modulation pattern that is asymmetric with respect to the axis along the processing direction. The shape becomes the third pattern control of the aforementioned inclined shape. The laser processing apparatus according to any one of claims 7 to 10, wherein, The modulation pattern includes an elliptical pattern for making the shape of the light-condensing region in the XY plane an ellipse with an X direction as a long side, and the XY plane includes an X intersecting the Y direction and the Z direction. direction and the aforementioned Y direction; In the second forming process, the control unit displays the modulation pattern on the spatial light modulator so that the intensity of the elliptical pattern becomes asymmetrical with respect to the axis along the X direction, thereby performing the use of The fourth pattern control for making the shape of the light-converging region into the inclined shape. The laser processing apparatus according to any one of claims 7 to 11, wherein, In the second forming process, the control unit displays the modulation pattern for forming a plurality of condensing points of the laser light arranged in the YZ plane along the shifting direction on the spatial light modulation The device is used to perform fifth pattern control for making the shape of the light-converging region including the plurality of light-converging points to be the inclined shape. A laser processing method for forming a modified region by irradiating a laser light on an object, comprising a first processing step and a second processing step, In the first processing step, the modification is formed on the object along the first region by relatively moving the condensing region of the laser light along the first region in the line set on the object. region, and form an oblique crack extending obliquely with respect to the Z direction intersecting with the incident surface from the modified region toward the opposite surface of the object on the opposite side to the incident surface of the laser light, In the second processing step, the modified region is formed on the object along the second region by relatively moving the light-converging region along the second region in the line, and the modified region is formed from the modified region. the aforementioned oblique crack extending toward the aforementioned opposite surface; The object has a crystal structure including a (100) plane, one (110) plane, the other (110) plane, a first crystal orientation orthogonal to the one (110) plane, and the other (110) plane. The (110) plane is a second crystal orientation orthogonal to the plane, and the (100) plane is referred to as the incident plane, The object is set as an annular line when viewed from the Z direction, the line including the arc-shaped first region and the arc-shaped second region having a boundary with the first region ; In the first processing step and the second processing step, When viewed from the Z direction, the light condensing region has a longitudinal direction, and the longitudinal direction of the light condensing region is made to be close to the first crystal orientation and the second crystal orientation and the light condensing region. The moving direction, that is, the direction of the larger angle between the processing progress directions is inclined with respect to the processing progress direction, the laser beam is shaped, and the processing progress is carried out in the first processing step and the second processing step. The forward and reverse directions are set to be the same, The point at which the second crystal orientation and the line are orthogonal is set as 0°, the point at which the first crystal orientation and the line are orthogonal is set at 90°, and the midway between the 0° and the 90° on the line is set When the point is set to 45°, in the first area and the second area, when viewed from the Z direction, the direction of the inclination of the longitudinal direction is the same as the diagonal crack with respect to the processing progress direction. The said boundary of the said 1st area|region and the said 2nd area|region is set so that the said 45 degree point may be included in one of the extending side being the same side.

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