WO2022014105A1

WO2022014105A1 - Laser processing device and laser processing method

Info

Publication number: WO2022014105A1
Application number: PCT/JP2021/013399
Authority: WO
Inventors: 剛志坂本; いく佐野; 銀治杉浦
Original assignee: 浜松ホトニクス株式会社
Priority date: 2020-07-15
Filing date: 2021-03-29
Publication date: 2022-01-20
Also published as: CN116075389A; TW202204077A; KR20230037547A; JPWO2022014105A1

Abstract

Provided is a laser processing device for irradiating a subject having a crystalline structure 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. For the subject, an annular line including a first area and a second area each having an arc shape when viewed in a Z direction intersecting with an incident plane of the laser light is set. The irradiation unit has a shaping unit for shaping the laser light.

Description

Laser processing equipment and laser processing method

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

Patent Document 1 describes a laser processing device including a holding mechanism for holding a work and a laser irradiation mechanism for irradiating a work held by the holding mechanism with a laser beam. In the laser processing apparatus described in Patent Document 1, a laser irradiation mechanism having a condenser lens is fixed to the base, and the movement of the work along the direction perpendicular to the optical axis of the condenser lens is performed by the holding mechanism. Will be implemented.

Japanese Patent No. 5456510 Japanese Unexamined Patent Publication No. 2020-609530

By the way, for example, in the manufacturing process of a semiconductor device, a trimming process for removing an outer edge portion thereof from a semiconductor wafer as an unnecessary portion may be performed. That is, in order to remove the outer edge portion of the object from the object, the focusing point of the laser light is relatively moved along the line extending in an annular shape inside the outer edge of the object, so as to be along the line. May form modified regions.

On the other hand, according to the knowledge of the present inventor, when the crack is extended from the modified region from the incident surface side of the laser beam of the object to the opposite surface during the trimming process, the object is used. There is a demand to extend the crack diagonally so as to be inclined with respect to the thickness direction, instead of extending the crack in the vertical direction along the thickness direction. This means that, for example, when a crack is stretched along the thickness direction, it leads to another member (for example, a wafer bonded to the object) arranged directly under the object along the thickness direction. This is to suppress it. At this time, according to the knowledge of the present inventor, there is room for improvement in setting the processing progress direction, which is the direction of relative movement of the condensing point, according to the crystal structure of the object.

Therefore, one aspect of the present disclosure is to provide a laser processing apparatus capable of setting a processing progress direction more appropriately according to the crystal structure of an object, and a laser processing method.

The present inventor obtained the following findings by proceeding with diligent research in order to solve the above problems. That is, when the crack is formed diagonally so as to be inclined with respect to the thickness direction, and the object has a crystal structure, the appropriate processing progress direction differs between one region and another region. There are cases. Therefore, it is possible to set a more appropriate machining progress direction by switching the order of the machining progress directions instead of setting the machining progress directions to the same direction in all the regions. One aspect of the present disclosure is based on such findings. To switch the order of the machining progress direction, for example, when machining along an annular line, the machining progress direction is set to counterclockwise (for example, forward direction) or clockwise (for example, reverse direction). Or to switch.

That is, the laser processing apparatus according to one aspect of the present disclosure is a laser processing apparatus for irradiating an object having a crystal structure with laser light to form a modified region, and is a support for supporting the object. A unit, an irradiation unit for irradiating a laser beam toward an object supported by a support unit, a moving unit for moving a condensing region of the laser light relative to the object, a moving unit, and a moving unit. A control unit for controlling the irradiation unit is provided, and the object has an annular shape including an arc-shaped first region and an arc-shaped second region when viewed from the Z direction intersecting the incident surface of the laser beam. The line is set, the irradiation unit has a molding unit for molding the laser beam, and the control unit controls the irradiation unit and the moving unit along the first region of the line. By moving the condensing region relative to each other, a modified region is formed on the object along the first region, and the modified region is directed toward the opposite surface opposite to the incident surface of the object in the Z direction. By controlling the irradiation part and the moving part, the light-collecting area is moved relative to the second area in the line, and the light-collecting area is moved to the second area. A second processing process of forming a modified region along the object and forming an oblique crack extending from the modified region toward the opposite surface is executed, and in the first processing process and the second processing process, The control unit switches the order of the processing progress direction, which is the moving direction of the condensing region, between the first processing process and the second processing process.

Alternatively, the laser processing method according to one aspect of the present disclosure is a laser processing method for irradiating an object having a crystal structure with laser light to form a modified region, and is a laser processing method for forming a modified region of the line set on the object. By relatively moving the condensing region of the laser beam along the first region, a modified region is formed on the object along the first region, and the laser light of the object is incident from the modified region. The first processing step of forming an oblique crack extending diagonally with respect to the Z direction intersecting the incident surface toward the opposite surface on the opposite side of the surface, and the relative movement of the condensing region along the second region of the line. The object is provided with a second processing step of forming a modified region in the object along the second region and forming an oblique crack extending from the modified region toward the opposite surface. , The annular line including the arc-shaped first region and the arc-shaped second region when viewed from the Z direction is set, and in the first processing step and the second processing step, the moving direction of the condensing region. The order of the processing progress is switched between the first processing process and the second processing process.

In these devices and methods, the object has a crystal structure. Then, here, when a modified region is formed on the object along the first region of the line that relatively moves the focused region of the laser beam (first processing process, first processing step), and the case where the modification region is formed. In the case of forming a modified region on the object along the second region of the line (second processing process, second processing step), the modified region is directed toward the opposite surface opposite to the incident surface of the object. A diagonal crack extending diagonally with respect to the Z direction (direction intersecting the incident surface) is formed. Therefore, as shown in the above findings, by switching the order of the processing progress direction between the first processing process (first region) and the second processing process (second region), it is possible to obtain more depending on the crystal structure of the object. The machining progress direction can be set appropriately.

In the laser processing apparatus according to one aspect of the present disclosure, the object includes the first portion and the second portion arranged in order from the opposite surface side along the Z direction, and the control unit refers to the first portion with respect to the first portion. The first machining process and the second machining process are executed while switching the order of the machining progress directions, and another machining process different from the first machining process and the second machining process is executed for the second part to perform another machining. In the processing, the control unit controls the irradiation unit and the moving unit to move the condensing region relative to the line while making the order and reverse of the processing progress direction the same throughout the line, thereby targeting along the line. The object may be formed with a modified region and cracks extending from the modified region along the Z direction. In this case, in the second portion where the crack is formed along the Z direction, the laser machining is performed with the same direction in the machining progress direction over the entire line. Therefore, even in the second portion, the time required for accelerating / decelerating the relative movement of the condensing region of the laser beam is reduced as compared with the case where the order of the processing progress direction is switched between the first region and the second region of the line.

In the laser processing apparatus according to one aspect of the present disclosure, in another processing, the control unit controls the molding unit so that the condensing region has a longitudinal direction when viewed from the Z direction, and the collection thereof. The laser beam may be formed so that the longitudinal direction of the optical region is along the processing progress direction. In this case, in the second portion where the crack is formed along the Z direction, the relationship between the longitudinal direction of the condensing region and the machining progress direction is changed between the machining of the first region and the machining of the second region of the line. Since it is not necessary to mold the laser beam as described above, the processing of the control unit is simplified.

In the laser machining apparatus according to one aspect of the present disclosure, the object includes a joining region joined to another member, and in the first machining process and the second machining process, the control unit is directed from the incident surface to the opposite surface. Increasingly, an oblique crack may be formed that is inclined from a position inside the joint region toward the outer edge of the joint region. In this case, when a part of the object is removed from the object with the diagonal crack as a boundary and the remaining part of the object remains, the remaining part of the object is outside beyond the joint region with other members of the object. It is avoided to extend to.

Here, the present inventor obtained the following findings by proceeding with further research based on the above findings. That is, in order to remove the outer edge portion of the object from the object, the focusing point of the laser light is relatively moved along the line extending in a ring shape inside the outer edge of the object, so as to be along the line. When the modified region is formed (trimming is performed), the quality of the trimmed surface of the object formed by removing the outer edge portion may deteriorate depending on the location. That is, according to the knowledge of the present inventor, there is a demand that diagonal cracks can be formed while suppressing deterioration of the quality of the trim surface of the object from which the outer edge portion has been removed.

The present inventor has obtained the following further findings regarding the suppression of quality deterioration of the trim surface. That is, first, the object has a (100) plane as a main plane, and has a first crystal orientation orthogonal to one (110) plane and a second crystal orientation orthogonal to another (110) plane. If, it is inclined with respect to the processing progress direction so that the angle between the first crystal orientation and the second crystal orientation and the processing progress direction (direction of relative movement of the condensing point) is closer to one of them. By forming the beam shape into a beam shape, deterioration of the quality of the outer surface can be suppressed (see, for example, Patent Document 2 above).

More specifically, when a crack extending from the modified region is pulled in the first crystal orientation, for example, the beam shape may be elongated and the longitudinal direction thereof may be oriented in the machining progress direction. Instead, it is tilted so as to approach the second crystal orientation opposite to the first crystal orientation side with respect to the processing progress direction. As a result, the crack extension force due to the elongated beam shape acts to cancel out the crack extension force due to the crystal orientation (crystal axis), so that the crack grows accurately along the processing progress direction. It is considered to be.

Further, when the crack extending from the modified region is pulled in the second crystal direction, for example, the beam shape is made long and the direction in the longitudinal direction thereof is not changed to the direction in the processing progress direction. It is tilted so as to approach the first crystal orientation opposite to the second crystal orientation side with respect to the traveling direction. As a result, it is considered that the crack extension force due to the elongated beam shape acts to cancel the crack extension force due to the crystal orientation, and the crack grows accurately along the processing progress direction. As a result, it is considered that the deterioration of the quality of the trim surface is suppressed. The present inventor has completed the following invention based on such findings.

That is, in the laser processing apparatus according to one aspect of the present disclosure, the object is the first plane orthogonal to the (100) plane, one (110) plane, another (110) plane, and one (110) plane. It has a crystal structure including one crystal orientation and a second crystal orientation orthogonal to another (110) plane, and is supported by a support portion so that the (100) plane is an incident plane. In the second processing, the control unit controls the molding unit so that the condensing region has a longitudinal direction when viewed from the Z direction, and the longitudinal direction of the condensing region is the first crystal orientation. The laser beam may be formed so that the angle between the second crystal orientation and the processing progress direction, which is the movement direction of the condensing region, is larger and the second crystal direction is inclined with respect to the processing progress direction. .. In this case, as shown in the above findings, quality deterioration of the trim surface is suppressed.

On the other hand, the present inventor has further researched based on the above findings, and even when the longitudinal direction of the beam shape is set as described above based on the processing progress direction and the crystal structure, the beam shape is formed. It was found that there is room for further suppression of quality deterioration of the trimmed surface depending on the relationship between the longitudinal orientation of the trimmer and the tilting direction of the diagonal crack. That is, when the longitudinal direction of the beam shape and the inclination direction of the oblique crack are on the same side with respect to the machining progress direction, the quality of the trim surface is relatively good, while the longitudinal direction of the beam shape. When the direction of the sloping crack and the inclination direction of the oblique crack are opposite to each other with respect to the machining progress direction, the quality of the trimmed surface may not be relatively good.

In solving this problem, the longitudinal orientation of the beam shape with respect to the machining progress direction depends on the crystal structure of the object (that is, as described above, the machining progress direction and the first crystal orientation and the second crystal orientation. Since it is determined by the magnitude relation of the angle of, the degree of freedom of change is small. Therefore, in order to make the relationship between the longitudinal direction of the beam shape and the inclination direction of the oblique cracks a combination that can obtain relatively good quality, the order of the machining progress direction should be changed to the crystal structure of the region to be machined. It is effective to switch as described above accordingly. That is, if the processing progress direction is appropriately set according to the crystal structure of the object as described above, it is possible to further suppress the deterioration of the quality of the trimmed surface. The following inventions have been made based on the above findings.

That is, in the laser machining apparatus according to one aspect of the present disclosure, in the first machining process and the second machining process, the control unit controls the moving unit so that the direction of inclination in the longitudinal direction is different when viewed from the Z direction. The order of the machining progress direction may be switched between the first machining process and the second machining process so that the diagonal crack extends on the same side as the machining progress direction. In this case, in both the first region and the second region, the direction of inclination in the longitudinal direction of the condensing region with respect to the processing progress direction and the side on which the oblique crack extends are the same side. Therefore, as shown in the above findings, the relationship between the longitudinal direction of the condensing region and the inclination direction of the oblique crack is a combination that can obtain relatively good quality, and the deterioration of quality is suppressed. In this way, it is possible to form diagonal cracks while suppressing deterioration of the quality of the trim surface of the object.

In the laser processing apparatus according to one aspect of the present disclosure, in another processing, the control unit moves the condensing region relative to the first region of the line without switching the processing progress direction. The first Z processing process for forming a modified region on the object along the first region and forming cracks extending in the Z direction from the modified region, and collecting along the second region of the line. By relatively moving the optical region, a modified region is formed in the object along the second region, and a second Z processing process for forming a crack extending in the Z direction from the modified region is executed. In the first Z processing and the second Z processing, the control unit controls the molding unit so that the condensing region has a longitudinal direction when viewed from the Z direction, and the longitudinal direction is the first. The laser beam is formed so that the angle between the crystal orientation and the second crystal orientation, which is the moving direction of the condensing region, is larger than the machining progress direction and is inclined with respect to the machining progress direction. May be good. In this case, also for the second portion, the longitudinal direction of the condensing region is set in the first region and the second region according to the machining progress direction, and the order of the machining progress directions is reversed in the first region and the second region. Compared with the case of switching, the time required for accelerating / decelerating the relative movement of the condensing region of the laser beam is reduced.

On the other hand, the present inventor has further researched based on the above findings, and even when the direction of the beam shape in the longitudinal direction is set as described above based on the processing progress direction and the crystal structure, the crystal structure It was found that there is room for further suppression of quality deterioration of the trimmed surface in a specific area in. That is, the object is on the (100) plane, one (110) plane, another (110) plane, the first crystal orientation orthogonal to the one (110) plane, and another (110) plane. When the crystal structure includes the second crystal orientation that is orthogonal to each other, the point where the line that relatively moves the condensing region of the laser beam and the second crystal orientation are orthogonal to each other is set to 0 °, and the line and the first crystal orientation are defined as 0 °. When the point where is orthogonal is 90 ° and the point between 0 ° and 90 ° in the line is 45 °, the longitudinal direction of the beam shape is along the machining progress direction in the region near 45 °. If so, the quality of the trimmed surface will be better. The following inventions have been made based on the above findings.

That is, in the laser processing apparatus according to one aspect of the present disclosure, the line has a point where the second crystal orientation and the line are orthogonal to each other at 0 ° and a point where the first crystal orientation and the line are orthogonal to each other at 90 °. In the region between the first region including 0 °, the second region including 90 °, and the region between the first region and the second region, where the point between 0 ° and 90 ° is 45 °. A third region having an arc shape including 45 ° is included, and the control unit relatively moves the light-collecting region along the third region of the line by controlling the irradiation unit and the moving unit. A third processing process is executed in which a modified region is formed in the object along the third region and diagonal cracks extending from the modified region toward the opposite surface are formed. In the third processing process, the control unit performs the third processing process. By controlling the molded portion, even if the laser beam is molded so that the condensing region has a longitudinal direction when viewed from the Z direction and the longitudinal direction of the condensing region is along the processing progress direction. good. In this case, in the third processing process for processing the third region including the point of 45 °, the longitudinal direction of the light collecting region of the laser beam is set to be along the processing progress direction. Therefore, as shown in the above findings, the quality of the trimmed surface in the region including the 45 ° point is better.

In the laser processing apparatus according to one aspect of the present disclosure, in the third processing process, the control unit controls the moving unit to reverse the order of the processing progress direction of the condensing region in the first processing process and the second processing process. It may be the same as the forward / reverse direction of the machining progress direction in one of the processes executed continuously with the third machining process. In this case, it is possible to shorten the time required for acceleration and deceleration for relative movement of the condensing region and suppress tact reduction.

In the laser machining apparatus according to one aspect of the present disclosure, in the first machining process and the second machining process, the control unit controls the moving unit so that the direction of inclination in the longitudinal direction when viewed from the Z direction is processed. The order of the machining progress direction may be switched between the first machining process and the second machining process so that the diagonal crack extends on the same side as the traveling direction. In this case, in both the first region and the second region, the direction of inclination in the longitudinal direction of the condensing region with respect to the processing progress direction and the side on which the oblique crack extends are the same side. Therefore, as shown in the above findings, the relationship between the longitudinal direction of the condensing region and the inclination direction of the oblique crack is a combination that can obtain relatively good quality, and the deterioration of quality is suppressed. In this way, it is possible to form diagonal cracks while suppressing deterioration of the quality of the trim surface of the object.

In the laser processing apparatus according to one aspect of the present disclosure, in the first processing process and the second processing process, the control unit collects light along the line while setting the position of the condensing region in the Z direction to the first Z position. By moving the optical region relative to each other, the first reforming region as a reforming region and the first forming process for forming cracks extending from the first reforming region on the object, and the position of the condensing region in the Z direction are determined. A crack extending from the second modified region and the second modified region as the modified region by relatively moving the condensing region along the line while setting the second Z position on the incident surface side of the first Z position. In the first forming process, the control unit sets the position of the condensing region in the Y direction intersecting the machining progress direction and the Z direction to the first Y position, and the second forming process is executed. In the two-forming process, the control unit sets the position of the light-collecting region in the Y direction to the second Y position shifted from the first Y position, and by controlling the molding unit, in the YZ plane including the Y direction and the Z direction. By forming the laser beam so that the shape of the condensing region of the light is inclined in the direction of the shift at least on the incident surface side from the center of the condensing region, the light is inclined in the direction of the shift in the YZ plane. Diagonal cracks may be formed as described above. By doing so, it is possible to suitably form an oblique crack inclined in the Z direction.

In the laser processing apparatus according to one aspect of the present disclosure, the molding unit includes a spatial light modulator for molding laser light by modulating the laser light according to a modulation pattern, and the irradiation unit includes a spatial light modulator. In the second forming process, the control unit controls the modulation pattern displayed on the spatial optical modulator to change the shape of the condensing region. The laser light may be formed by modulating the laser light so as to have an inclined shape. In this case, the laser beam can be easily formed by using the spatial light modulator.

In the laser processing apparatus according to one aspect of the present disclosure, the modulation pattern includes a coma aberration pattern for imparting coma aberration to the laser light, and in the second forming process, the control unit is used for coma aberration due to the coma aberration pattern. By controlling the size of the light-collecting region, the first pattern control for making the shape of the condensing region an inclined shape may be performed. According to the findings of the present inventor, in this case, the shape of the condensing region in the YZ plane is formed in an arc shape. That is, in this case, the shape of the condensing region is inclined in the shift direction on the incident surface side from the center of the condensing region, and is opposite to the shift direction on the side opposite to the incident surface from the center of the condensing region. Is tilted to. Even in this case, it is possible to form an oblique crack that is inclined in the shift direction.

In the laser processing apparatus according to one aspect of the present disclosure, the modulation pattern includes a spherical aberration correction pattern for correcting the spherical aberration of the laser light, and in the second forming process, the control unit is the incident pupil surface of the condenser lens. By offsetting the center of the spherical aberration correction pattern in the Y direction with respect to the center of the light, the second pattern control for making the shape of the condensing region an inclined shape may be performed. According to the findings of the present inventor, in this case as well, the shape of the condensing region in the YZ plane can be formed in an arc shape and an oblique crack inclined in the shift direction can be formed, as in the case of using the coma aberration pattern. Is.

In the laser processing apparatus according to one aspect of the present disclosure, in the second forming process, the control unit causes the spatial light modulator to display a modulation pattern that is asymmetric with respect to the axis along the processing progress direction, thereby displaying a condensing region. The third pattern control for making the shape of the slanted shape may be performed. According to the findings of the present inventor, in this case, the entire shape of the condensing region in the YZ plane can be tilted in the shift direction. Even in this case, it is possible to form an oblique crack that is inclined in the shift direction.

In the laser processing apparatus according to one aspect of the present disclosure, the modulation pattern is an ellipse having the shape of the condensing region in the XY plane including the X direction and the Y direction intersecting the Y direction and the Z direction as the longitudinal direction in the X direction. In the second forming process, which includes an elliptical pattern for shaping, the control unit displays the modulation pattern on the spatial light modulator so that the intensity of the elliptical pattern is asymmetric with respect to the axis along the X direction. By doing so, the fourth pattern control for making the shape of the condensing region an inclined shape may be performed. According to the findings of the present inventor, even in this case, the shape of the condensing region in the YZ plane can be formed in an arc shape, and an oblique crack inclined in the shift direction can be formed.

In the laser processing apparatus according to one aspect of the present disclosure, in the second forming process, in the second forming process, the control unit forms a modulation pattern for forming a plurality of focusing points of laser light arranged along the shift direction in the YZ plane. May be displayed on the spatial light modulator to control the fifth pattern in order to make the shape of the condensing region including a plurality of condensing points an inclined shape. According to the knowledge of the present inventor, it is possible to form an oblique crack inclined in the shift direction in this case as well.

In the laser processing apparatus according to one aspect of the present disclosure, in the first region, the point where the second crystal orientation and the line are orthogonal is set to 0 °, and the point where the first crystal orientation and the line are orthogonal is set to 90 °, and the line is set. Assuming that the point between 0 ° and 90 ° in is 45 °, the region may include a region from 0 ° to 45 °, and the second region may include a region from 45 ° to 90 °. Thereby, when the object is a wafer having the (100) plane as the incident surface, it is possible to surely suppress the deterioration of the quality of the trim surface of the object depending on the location.

According to one aspect of the present disclosure, it is possible to provide a laser processing apparatus capable of forming diagonal cracks while suppressing deterioration of the quality of the trim surface of the object from which the outer edge portion has been removed, and a laser processing method.

FIG. 1 is a schematic diagram showing a configuration of a laser processing apparatus according to an embodiment. FIG. 2 is a schematic diagram showing the configuration of the laser irradiation unit shown in. FIG. 3 is a diagram showing the 4f lens unit shown in FIG. FIG. 4 is a diagram showing the spatial light modulator shown in FIG. FIG. 5 is a cross-sectional view of an object for explaining the findings of oblique crack formation. FIG. 6 is a cross-sectional view of an object for explaining the findings of oblique crack formation. FIG. 7 is a diagram showing the beam shape of the focused region of the laser beam. FIG. 8 is a diagram showing the offset of the modulation pattern. FIG. 9 is a cross-sectional photograph showing a state in which diagonal cracks are formed. FIG. 10 is a schematic plan view of the object. FIG. 11 is a cross-sectional photograph showing a state in which diagonal cracks are formed. FIG. 12 is a cross-sectional photograph showing a state in which diagonal cracks are formed. FIG. 13 is a diagram showing an example of a modulation pattern. FIG. 14 is a diagram showing the intensity distribution of the condenser lens on the entrance pupil surface and the beam shape of the condenser region. FIG. 15 is a diagram showing observation results of the beam shape of the condensing region and the intensity distribution of the condensing region. FIG. 16 is a diagram showing an example of a modulation pattern. FIG. 17 is a diagram showing another example of an asymmetric modulation pattern. FIG. 18 is a diagram showing the intensity distribution of the condenser lens on the entrance pupil surface and the beam shape of the condenser region. FIG. 19 is a diagram showing an example of a modulation pattern and the formation of a condensing region. FIG. 20 is a diagram showing an object to be processed. FIG. 21 is a diagram showing an object to be processed. FIG. 22 is a schematic diagram showing the beam shape of the condensing region. FIG. 23 is a schematic diagram showing the beam shape of the condensing region. FIG. 24 is a diagram showing one step of the trimming process. FIG. 25 is a diagram showing one step of the trimming process. FIG. 26 is a diagram showing one step of the trimming process. FIG. 27 is a diagram showing one step of the trimming process. FIG. 28 is a diagram showing one step of the trimming process. FIG. 29 is a diagram showing one step of the trimming process. FIG. 30 is a diagram showing an object of laser machining according to an embodiment. FIG. 31 is a cross-sectional view of the object shown in FIG. FIG. 32 is a plan view of the object shown in FIG. FIG. 33 is a cross-sectional photograph showing the processing result. FIG. 34 is a cross-sectional photograph showing the processing result. FIG. 35 is a schematic diagram for explaining a processing test. FIG. 36 is a schematic view showing the relationship between the machining progress direction, the beam shape, and the oblique crack in the machining test. FIG. 37 is a table showing the results of the machining tests shown in FIGS. 35 and 36. FIG. 38 is a table showing the results of the processing test. FIG. 39 is a cross-sectional photograph showing the result of the processing test. FIG. 40 is a diagram showing one step of laser processing according to one embodiment. FIG. 41 is a diagram showing one step of laser processing according to one embodiment. FIG. 42 is a diagram showing one step of laser processing according to one embodiment. FIG. 43 is a diagram showing one step of laser processing according to one embodiment. FIG. 44 is a diagram showing one step of laser processing according to one embodiment. FIG. 45 is a diagram showing one step of laser processing according to one embodiment. FIG. 46 is a diagram showing one step of laser processing according to one embodiment. FIG. 47 is a diagram showing one step of laser processing according to one embodiment. FIG. 48 is a diagram showing an object of laser machining according to an embodiment. FIG. 49 is a table showing the results of the processing test. FIG. 50 is a table showing the results of the processing test. FIG. 51 is a diagram showing an object according to the present embodiment. FIG. 52 is a diagram showing a beam shape when processing the third region. FIG. 53 is a table showing the processing results in the beam shape shown in FIG. 52. FIG. 54 is a diagram for explaining the laser machining according to the third embodiment. FIG. 55 is a diagram for explaining the laser machining according to the fourth embodiment.

Hereinafter, one embodiment will be described in detail with reference to the drawings. In each figure, the same or corresponding parts may be designated by the same reference numerals, and duplicate description may be omitted. Further, each figure may show a Cartesian coordinate system defined by the X-axis, the Y-axis, and the Z-axis.
[Overview of laser processing equipment and laser processing]

FIG. 1 is a schematic diagram showing a configuration of a laser processing apparatus according to an embodiment. As shown in FIG. 1, the laser processing apparatus 1 includes a stage (support portion) 2, an irradiation unit 3, moving

units

4 and 5, and a control unit 6. The laser processing device 1 is a device for forming a modified region 12 on the object 11 by irradiating the object 11 with the laser beam L.

The stage 2 supports the object 11 by holding the film attached to the object 11, for example. The stage 2 can rotate about an axis parallel to the Z direction as a rotation axis. The stage 2 may be movable along each of the X direction and the Y direction. 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 the laser beam L having transparency to the object 11 and irradiates the object 11. When the laser beam L is focused inside the object 11 supported by the stage 2, the laser beam L is particularly absorbed in the portion of the laser beam L corresponding to the focused region C (for example, the central Ca described later). A modified region 12 is formed inside the object 11. Although the detailed description will be described later, the condensing region C is a region within a predetermined range from the position where the beam intensity of the laser beam L is highest or the position of the center of gravity of the beam intensity.

The modified region 12 is a region whose density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding non-modified region. The modified region 12 includes, for example, a melt processing region, a crack region, a dielectric breakdown region, a refractive index change region, and the like. The modified region 12 may be formed so that a crack extends from the modified region 12 to the incident side of the laser beam L and the opposite side thereof. Such modified regions 12 and cracks are utilized, for example, for cutting the object 11.

As an example, when the stage 2 is moved along the X direction and the condensing region C is relatively moved along the X direction with respect to the object 11, a plurality of modified spots 12s are 1 along the X direction. Formed to line up. One modified spot 12s is formed by irradiation with one pulse of laser light L. The modified region 12 in one row is a set of a plurality of modified spots 12s arranged in one row. Adjacent modified spots 12s may be connected to each other or separated from each other depending on the relative moving speed of the condensing region C with respect to the object 11 and the repetition frequency of the laser beam L.

The moving unit 4 moves the first moving unit 41 that moves the stage 2 in one direction in the plane that intersects (orthogonally) in the Z direction, and moves the stage 2 in another direction in the plane that intersects (orthogonally) in the Z direction. The second moving unit 42 and the like are included. As an example, the first moving unit 41 moves the stage 2 along the X direction, and the second moving unit 42 moves the stage 2 along the Y direction. Further, the moving unit 4 rotates the stage 2 with an axis parallel to the Z direction as a rotation axis. The moving unit 5 supports the irradiation unit 3. The moving unit 5 moves the irradiation unit 3 along the X direction, the Y direction, and the Z direction. By moving the stage 2 and / or the irradiation unit 3 in the state where the condensing region C of the laser beam L is formed, the condensing region C is relatively moved with respect to the object 11. That is, the moving

units

4 and 5 move at least one of the stage 2 and the irradiation unit 3 in order to move the condensing region C of the laser beam L relative 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 has a processing unit, a storage unit, and an input receiving unit (not shown). The processing unit is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the processing unit, the processor executes software (program) read into the memory or the like, and controls reading and writing of data in the memory and storage, and communication by the communication device. The storage unit is, for example, a hard disk or the like, and stores various data. The input receiving unit is an interface unit that displays various information and accepts input of various information from the user. The input reception unit constitutes a GUI (Graphical User Interface).

FIG. 2 is a schematic diagram showing the configuration of the irradiation unit shown in FIG. FIG. 2 shows a virtual line A indicating a laser machining schedule. 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 beam L by, for example, a pulse oscillation method. The irradiation unit 3 does not have a light source 31, and may be configured to introduce the laser beam L from the outside of the irradiation unit 3. The spatial light modulator 7 modulates the laser beam L output from the light source 31. The condenser lens 33 condenses the laser beam L modulated by the spatial light modulator 7 and output from the spatial light modulator 7 toward the object 11.

As shown in FIG. 3, the 4f lens unit 34 has a pair of

lenses

34A and 34B arranged on the optical path of the laser beam L from the spatial light modulator 7 to the condenser lens 33. The pair of

lenses

34A and 34B constitute 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. As a result, the image of the laser beam L on the modulation surface 7a of the spatial light modulator 7 (the image of the laser beam L modulated by the spatial light modulator 7) is transferred to the incident pupil surface 33a of the condenser lens 33 ( Image). Note that Fs in the figure indicates a Fourier plane.

As shown in FIG. 4, the spatial light modulator 7 is a spatial light modulator (SLM: Spatial Light Modulator) of a reflective liquid crystal (LCOS: Liquid Crystal on Silicon). In the spatial light modulator 7, the drive circuit layer 72, the pixel electrode layer 73, the reflective film 74, the alignment film 75, the liquid crystal layer 76, the alignment film 77, the transparent conductive film 78, and the transparent substrate 79 are arranged in this order on the semiconductor substrate 71. It is configured by being laminated with.

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

The reflective 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 opposite to the reflective film 74. Each of the alignment films 75, 77 is formed of, for example, a polymer material such as polyimide, and the contact surface of each of the alignment films 75, 77 with the liquid crystal layer 76 is subjected to, for example, a rubbing treatment. The alignment films 75 and 77 arrange the liquid crystal molecules 76a contained in the liquid crystal layer 76 in 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 a light-transmitting and conductive material such as ITO. The transparent substrate 79 and the transparent conductive film 78 transmit the laser beam L.

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

That is, with the modulation pattern displayed on the liquid crystal layer 76, the laser beam L is incident on the liquid crystal layer 76 from the outside via the transparent substrate 79 and the transparent conductive film 78, and is reflected by the reflective film 74 to be reflected on the liquid crystal layer. When the light is emitted from the 76 to the outside via the transparent conductive film 78 and the transparent substrate 79, the laser beam L is modulated according to the modulation pattern displayed on the liquid crystal layer 76. As described above, according to the spatial light modulator 7, the modulation of the laser beam L (for example, the modulation of the intensity, amplitude, phase, polarization, etc. of the laser beam L) is performed by appropriately setting the modulation pattern to be displayed on the liquid crystal layer 76. ) Is possible. The modulation surface 7a shown in FIG. 3 is, for example, a liquid crystal layer 76.

As described above, the laser beam L output from the light source 31 is incident on the condenser lens 33 via the spatial light modulator 7 and the 4f lens unit 34, and is condensed in the object 11 by the condenser lens 33. As a result, cracks extending from the modified region 12 and the modified region 12 are formed in the object 11 in the light collecting region C. Further, the control unit 6 controls the moving

units

4 and 5 to move the condensing region C relative to the object 11, thereby causing the modified region 12 and the crack along the moving direction of the condensing region C. Will be formed.
[Explanation of findings regarding diagonal crack formation]

Here, the direction of relative movement (machining progress direction) of the light collecting region C at this time is defined as the X direction. Further, the direction that intersects (orthogonally) the first surface 11a, which is the incident surface of the laser beam L on the object 11, is defined as the Z direction. Further, the direction that intersects (orthogonally) the X direction and the Z direction is defined as the Y direction. The X direction and the Y direction are directions along the first surface 11a. The Z direction may be defined as the optical axis of the condenser lens 33 and the optical axis of the laser beam L focused toward the object 11 via the condenser lens 33.

As shown in FIG. 5, in the intersection surface (YZ surface S including the Y direction and the Z direction) intersecting the X direction which is the machining progress direction, the line RA (here, the line RA inclined with respect to the Z direction and the Y direction). There is a need to form cracks diagonally along the line RA) that slopes from the Y direction at a predetermined angle θ. The inventor's knowledge of such diagonal crack formation will be described with reference to processing examples.

Here, the modified

regions

12a and 12b are formed as the modified regions 12. As a result, the crack 13a extending from the modified region 12a and the crack 13b extending from the modified region 12b are connected to form a crack 13 extending diagonally along the line RA. Here, first, as shown in FIG. 6, the condensing region C1 is formed while the first surface 11a of the object 11 is used as the incident surface of the laser beam L. On the other hand, on the first surface 11a side of the condensing region C1, the condensing region C2 is formed while the first surface 11a is the incident surface of the laser beam L. At this time, the condensing region C2 is shifted from the condensing region C1 by a distance Sz in the Z direction, and is also shifted from the condensing region C1 in the Y direction by a distance Sy. 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 modulating the laser beam L using the spatial light modulator 7, the beam shape of the condensing region C (at least the condensing region C2) in the YZ plane S is at least. The shape is inclined so as to be inclined in the shift direction (here, the negative side in the Y direction) with respect to the Z direction on the first surface 11a side of the center Ca of the light collection region C. In the example of FIG. 7, the first surface 11a side of the central Ca is inclined to the negative side in the Y direction with respect to the Z direction, and the side opposite to the first surface 11a of the central Ca is also inclined in the Z direction. It has an arc shape that inclines to the negative side in the Y direction. The beam shape of the condensing region C in the YZ plane S is the intensity distribution of the laser beam L in the condensing region C in the YZ plane S.

In this way, at least two condensing regions C1 and C2 are shifted in the Y direction, and at least the beam shape of the condensing region C2 (here, both the condensing regions C1 and C2) is made an inclined shape. As shown in (a) of 9, it is possible to form a crack 13 extending diagonally. In addition, for example, by controlling the modulation pattern of the spatial light modulator 7, the condensing regions C1 and C2 may be formed at the same time by branching the laser beam L to form the modified region 12 and the crack 13 (the modified region 12 and the crack 13 may be formed (). After forming the modified region 12a and the crack 13a by forming the light-collecting region C1 (multifocal processing), the modified region 12b and the crack 13b may be formed by forming the light-collecting region C2 (single-pass processing). ).

Further, by forming another condensing region between the condensing region C1 and the condensing region C2, as shown in FIG. 9B, between the modified region 12a and the modified region 12b. Another modified region 12c may be interposed to form a longer and diagonally extending crack 13.

Next, the knowledge for making the beam shape in the YZ plane S of the condensing region C an inclined shape will be described. First, the definition of the condensing region C will be specifically described. Here, the light-collecting region C is a region within a predetermined range from the central Ca (for example, a range of ± 25 μm from the central Ca in the Z direction). As described above, the central Ca is the position where the beam intensity is highest or the position of the center of gravity of the beam intensity. The position of the center of gravity of the beam intensity is on the optical axis of the laser beam L in a state where the modulation pattern for shifting the optical axis of the laser beam L, such as a modulation pattern for branching the laser beam L, is not performed. This is the position where the center of gravity of the beam intensity is located. The position where the beam intensity is highest and the center of gravity of the beam intensity can be obtained as follows. That is, the laser beam L is irradiated to the object 11 in a state where the output of the laser beam L is lowered to the extent that the modified region 12 is not formed on the object 11 (below the processing threshold value). At the same time, the reflected light of the laser beam L from the surface of the object 11 opposite to the incident surface of the laser beam L (here, the second surface 11b) is transferred to a plurality of positions F1 to the Z direction shown in FIG. 15, for example. The F7 is imaged with a camera. As a result, the position and the center of gravity where the beam intensity is highest can be obtained based on the obtained image. The modified region 12 is formed in the vicinity of the central Ca.

There is a method of offsetting the modulation pattern in order to make the beam shape in the condensing region C an inclined shape. More specifically, the spatial light modulator 7 has a distortion correction pattern for correcting the distortion of the wavefront, a grating pattern for branching the laser beam, a slit pattern, an astigmatism pattern, a coma aberration pattern, and the like. Various patterns such as spherical aberration correction patterns are displayed (patterns in which these are superimposed are displayed). Of these, as shown in FIG. 8, the beam shape of the condensing region C can be adjusted by offsetting the spherical aberration correction pattern Ps.

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

By offsetting the spherical aberration correction pattern Ps in this way, the beam shape of the condensing region C of the laser beam L is deformed into an arc-shaped inclined shape as shown in FIG. 7. Offsetting the spherical aberration correction pattern Ps as described above corresponds to giving coma aberration to the laser beam L. Therefore, the beam shape of the condensing region C may be an inclined shape by including the coma aberration pattern for imparting coma aberration to the laser beam L in the modulation pattern of the spatial light modulator 7. As the coma aberration pattern, a pattern corresponding to the 9th term (Y component of the third-order coma aberration) of the Zernike polynomial, in which coma aberration occurs in the Y direction, can be used.

Next, I will explain the knowledge about the relationship between the crystallinity of the object 11 and the crack 13. FIG. 10 is a schematic plan view of the object. Here, the object 11 is a silicon wafer (t775 μm, <100>, 1 Ω · cm), and a notch 11d is formed. An example of the first machining in which the X direction, which is the machining progress direction, is aligned with the 0 ° (110) plane with respect to the object 11, is shown in FIG. 11A, and the second machining in which the X direction is aligned with 15 °. An example is shown in FIG. 11 (b), a third machining example adjusted to 30 ° is shown in FIG. 12 (a), and a fourth machining example matched to a 45 ° (100) plane is shown in FIG. 12 (b). Shown in. In each processing example, the angle θ of the line RA in the YZ plane S from the Y direction is 71 °.

Further, in each processing example, the condensing region C1 is relatively moved in the X direction as the first pass to form the modified region 12a and the crack 13a, and then the condensing region C2 is relatively moved in the X direction as the second pass. The single pass processing is performed to form the modified region 12b and the crack 13b. The processing conditions for the first pass and the second pass were as follows. The CP below indicates the strength of the light collection correction, and the coma (LBA offset Y) indicates the amount of offset of the spherical aberration correction pattern Ps in the Y direction in pixel units of the spatial light modulator 7. It is a thing.

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

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

As shown in FIGS. 11 and 12, in any case, the crack 13 could be formed along the line RA inclined at 71 ° with respect to the Y direction. That is, the desired line does not depend on the influence of the (110) plane, the (111) plane, the (100) plane, etc., which are the main cleavage planes of the object 11, that is, regardless of the crystal structure of the object 11. A crack 13 extending diagonally along the RA could be formed.

Note that the control of the beam shape for forming the crack 13 extending diagonally in this way is not limited to the above example. Subsequently, another example for making the beam shape an inclined shape will be described. As shown in FIG. 13A, the laser beam L is modulated by the modulation pattern PG1 that is asymmetric with respect to the axis Ax along the X direction, which is the processing progress direction, and the beam shape of the condensing region C is inclined. May be. The modulation pattern PG1 includes the grating pattern Ga on the negative side in the Y direction with respect to the axis Ax along the X direction passing through the center Lc of the beam spot of the laser beam L in the Y direction, and is on the positive side in the Y direction with respect to the axis Ax. Includes a non-modulation region Ba. 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. Note that FIG. 13B shows the modulation pattern PG1 of FIG. 13A inverted so as to correspond to the entrance pupil surface 33a of the condenser lens 33.

FIG. 14A shows the intensity distribution of the laser beam L on the entrance pupil surface 33a of the condenser lens 33. As shown in FIG. 14A, by using such a modulation pattern PG1, the portion of the laser beam L incident on the spatial light modulator 7 that is modulated by the grating pattern Ga is the condenser lens 33. No longer incident on the incident pupil surface 33a. As a result, as shown in FIG. 14B and FIG. 15, the beam shape of the condensing region C in the YZ plane S is made to be an inclined shape in which the entire beam shape is inclined in one direction with respect to the Z direction. Can be done.

That is, in this case, the beam shape of the condensing region C is inclined to the negative side in the Y direction with respect to the Z direction on the first surface 11a side of the center Ca of the condensing region C, and the condensing region. On the side opposite to the first surface 11a from the center Ca of C, it is inclined to the positive side in the Y direction with respect to the Z direction. It should be noted that each figure of FIG. 15 (b) shows the intensity distribution of the laser beam L in the XY plane at each position F1 to F7 in the Z direction shown in FIG. 15 (a), and is actually observed by a camera. The result. Even when the beam shape of the condensing region C is controlled in this way, the crack 13 extending diagonally can be formed as in the above example.

Further, as the modulation pattern asymmetric with respect to the axis line Ax, the modulation patterns PG2, PG3, and PG4 shown in FIG. 16 can also be adopted. The modulation pattern PG2 includes an unmodulated region Ba and a grating pattern Ga arranged in order away from the axis Ax on the negative side in the Y direction with respect to the axis Ax, and a non-modulated region on the positive side in the Y direction with respect to the axis Ax. Including 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 an unmodulated region Ba and a grating pattern Ga arranged in order away from the axis Ax on the negative side in the Y direction from the axis AX, and also on the positive side in the Y direction from the axis Ax. It includes an unmodulated region Ba and a grating pattern Ga sequentially arranged in a direction away from the axis Ax. In the modulation pattern PG3, the ratios of the non-modulation region Ba and the grating pattern Ga are different between the positive side in the Y direction and the negative side in the Y direction with respect to the axis Ax (relatively unmodulation on the negative side in the Y direction). (By narrowing the region Ba), it is asymmetric with respect to the axis Ax.

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

In any of the above modulation patterns PG2 to PG4, the beam shape of the condensing region C shall be an inclined shape that is inclined to the negative side in the Y direction with respect to the Z direction at least on the first surface 11a side of the central Ca. Can be done. That is, in order to control the beam shape of the focusing region C so as to be inclined to the negative side in the Y direction with respect to the Z direction at least on the first surface 11a side of the center Ca, the modulation patterns PG1 to PG4 are used. Alternatively, not limited to the modulation patterns PG1 to PG4, an asymmetric modulation pattern including the grating pattern Ga can be used.

Further, the asymmetric modulation pattern for making the beam shape of the focusing region C an inclined shape is not limited to the one using the grating pattern Ga. FIG. 17 is a diagram showing another example of an asymmetric modulation pattern. As shown in FIG. 17A, the modulation pattern PE includes the elliptical pattern Ew on the negative side in the Y direction with respect to the axis Ax and the elliptical pattern Es on the positive side in the Y direction with respect to the axis Ax. Note that FIG. 17B shows the modulation pattern PE of FIG. 17A inverted so as to correspond to the entrance pupil surface 33a of the condenser lens 33.

As shown in FIG. 17 (c), the elliptical patterns Ew and Es both have an elliptical shape in which the beam shape of the condensing region C on the XY plane including the X direction and the Y direction is the longitudinal direction in the X direction. It is a pattern for. However, the modulation intensity is different between the elliptical pattern Ew and the elliptical pattern Es. More specifically, the intensity of the modulation by the elliptical pattern Es is made larger than the intensity of the modulation by the elliptical pattern Ew. That is, the condensing region Cs formed by the laser beam L modulated by the elliptical pattern Es has an elliptical shape longer in the X direction than the condensing region Cw formed by the laser beam L modulated by the elliptical pattern Ew. Has been done. Here, the elliptical pattern Es, which is relatively strong on the negative side in the Y direction with respect to the axis Ax, is arranged.

As shown in FIG. 18A, by using such a modulation pattern PE, the beam shape of the condensing region C in the YZ plane S can be changed in the Z direction on the first plane 11a side of the central Ca. On the other hand, the shape can be inclined so as to be inclined to the negative side in the Y direction. In particular, in this case, the beam shape of the condensing region C in the YZ plane S is inclined to the negative side in the Y direction with respect to the Z direction even on the side opposite to the first plane 11a from the central Ca. It becomes arcuate as a whole. It should be noted that each figure of FIG. 18B shows the intensity distribution of the laser beam L in the XY plane at each position H1 to F8 in the Z direction shown in FIG. 18A, and is actually observed by a camera. The result.

Furthermore, the modulation pattern for making the beam shape of the condensing region C an inclined shape is not limited to the above asymmetric pattern. As an example, as such a modulation pattern, as shown in FIG. 19, condensing point CIs are formed at a plurality of positions in the YZ plane S, and the entire plurality of condensing point CIs (multiple condensing points) are formed. A pattern for modulating the laser beam L so as to form a focused region C having an inclined shape (including CI) can be mentioned. As an example, such a modulation pattern can be formed based on the axicon lens pattern. 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 formed accurately 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 performed by properly using various modulation patterns according to the requirements.

The focusing point CI is, for example, a point where unmodulated laser light is focused. As described above, according to the findings of the present inventor, at least two

modified regions

12a and 12b in the YZ plane S are shifted in the Y direction and the Z direction, and a condensing region in the YZ plane S. By making the beam shape of C an inclined shape, it is possible to form a crack 13 extending diagonally so as to be inclined in the Y direction with respect to the Z direction.

When controlling the beam shape, when the offset of the spherical aberration correction pattern is used, when the coma aberration pattern is used, and when the elliptical pattern is used, a part of the laser beam is used by using the diffraction grating pattern. Compared to the case of cutting, it is possible to process with high energy. Further, in these cases, it is effective when the formation of cracks is emphasized. Further, when the coma aberration pattern is used, it is possible to make only the beam shape of a part of the condensing region an inclined shape in the case of multifocal processing. Further, when the axicon lens pattern is used, the use of other patterns is effective when the formation of the modified region is emphasized as compared with the other patterns.
[Example of trimming]

Next, an example of trimming will be explained. The trimming process is a process for removing an unnecessary portion in the object 11. The trimming process includes a laser processing method for forming a modified region 12 on the object 11 by aligning the condensing region with the object 11 and irradiating the object 11 with laser light L. The object 11 includes, for example, a semiconductor wafer formed in a disk shape. The object is not particularly limited, and may be formed of various materials or may have various shapes. A functional element (not shown) is formed on the second surface 11b of the object 11. The functional element is, for example, a light receiving element such as a photodiode, a light emitting element such as a laser diode, a circuit element such as a memory, or the like.

20 and 21 are diagrams showing an object to be processed. As shown in FIGS. 20 and 21, the effective region R and the removal region E are set in the object 11. The effective domain R is a portion corresponding to the semiconductor device to be acquired. The effective domain R here is a disk-shaped portion including a central portion when the object 11 is viewed from the thickness direction. The removal region E is a region outside the effective region R in the object 11. The removal region E is an outer edge portion of the object 11 other than the effective region R. The removal region E here is an annular portion surrounding the effective region R. The removal region E includes a peripheral portion (bevel portion of the outer edge) when the object 11 is viewed from the thickness direction. The effective region R and the removal region E can be set in the control unit 6. The effective area R and the removal area E may have coordinates specified.

Stage 2 is a support portion on which the object 11 is placed. In the stage 2 of the present embodiment, the first surface 11a of the object 11 is on the upper side of the laser beam incident surface side (the second surface 11b is on the lower side of the stage 2 side). 11 is placed. The stage 2 has a rotation axis Cx provided at the center thereof. The rotation axis Cx is an axis extending along the Z direction. The stage 2 can rotate 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 to form a modified region inside the object 11. The irradiation unit 3 is attached to the moving unit 5. The irradiation unit 3 can move linearly in the Z direction by the driving force of a known driving device such as a motor. The irradiation unit 3 can move 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 a spatial light modulator 7. The spatial light modulator 7 also refers to the shape of the condensing region C in the plane perpendicular to the optical axis of the laser beam L (that is, the shape of the condensing region C when viewed from the Z direction) (hereinafter, also referred to as “beam shape”). ) Is formed. 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 shapes the beam shape into an elliptical shape by displaying a modulation pattern in which the beam shape is an elliptical shape.

The beam shape is not limited to an elliptical shape, and may be a long shape. The beam shape may be a flat circular shape, an oval shape, or a track shape. The beam shape may be a long triangular shape, a rectangular shape, or a polygonal shape. The modulation pattern of the spatial light modulator 7 that realizes such a beam shape may include at least one of a slit pattern and an astigmatic pattern. When the laser beam L has a plurality of condensing regions C due to non-point aberration or the like, the shape of the condensing region C on the most upstream side in the optical path of the laser beam L among the plurality of condensing regions C is the present implementation. It is a beam shape of the form (same for other laser beams). The longitudinal direction here is the major axis direction of the elliptical shape related to the beam shape, and is also referred to as the elliptical major axis direction.

The beam shape is not limited to the shape of the condensing point, and may be a shape near the condensing point, in short, it may be a part of the condensing region C. For example, in the case of the laser beam L having astigmatism, as shown in FIG. 22 (a), the beam shape has the longitudinal direction NH in the region on the laser beam incident surface side near the condensing point. In 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 laser light incident surface side near the condensing point), the distribution has a strong intensity in the longitudinal direction NH. The direction in which the beam intensity is strong coincides with the longitudinal direction NH.

In the case of the laser beam L having non-point aberration, as shown in FIG. 22 (c), in the region on the opposite surface side of the laser beam incident surface near the condensing point, the beam shape is on the laser beam incident surface side. It has a longitudinal NH0 perpendicular to the longitudinal NH of the region (see (a) in FIG. 22). In 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 beam incident surface near the condensing point), the distribution has a strong intensity in the longitudinal direction NH0. The direction in which the beam intensity is strong coincides with the longitudinal direction NH0. In the case of the laser beam L having astigmatism, as shown in FIG. 22 (b), the condensing region C is located in the region between the laser beam incident surface side and the opposite surface side in the vicinity of the condensing point. It has no longitudinal direction and is circular.

In the case of the laser beam L having such astigmatism, the condensing region C targeted by the present embodiment includes a region on the laser beam incident surface side in the vicinity of the condensing point, and is targeted by the present embodiment. The beam shape is the beam shape shown in FIG. 22 (a).

By adjusting the modulation pattern of the spatial light modulator 7, the position of the focused region C having the beam shape shown in FIG. 22 (a) can be controlled as desired. For example, it can be controlled to have the beam shape shown in FIG. 22 (a) in the region on the opposite surface side of the laser beam incident surface near the condensing point. Further, for example, it can be controlled to have the beam shape shown in FIG. 22 (a) in the region between the laser beam incident surface side and the opposite surface side in the vicinity of the condensing point. The position of a part of the condensing region C is not particularly limited, and may be any position between the laser beam incident surface of the object 11 and the opposite surface thereof.

Further, for example, when a slit or an elliptical optical system with modulation pattern control and / or a mechanical mechanism is used, as shown in FIG. 23 (a), in the region on the laser light incident surface side near the condensing point, The beam shape has longitudinal NH. In the beam intensity distribution in the plane of the beam shape of FIG. 23 (a) (in the plane at the position in the Z direction on the laser light incident surface side near the condensing point), the distribution has a strong intensity in the longitudinal direction NH. The direction in which the beam intensity is strong coincides with the longitudinal direction NH.

When a slit or an elliptical optical system is used, as shown in FIG. 23 (c), in the region on the opposite side of the laser beam incident surface near the condensing point, the beam shape is the region on the laser beam incident surface side. Has the same longitudinal NH as (see (a) in FIG. 22). In the beam intensity distribution in the plane of the beam shape of FIG. 23 (c) (in the plane at the position in the Z direction on the opposite side of the laser beam incident surface near the condensing point), the distribution has a strong intensity in the longitudinal direction NH. The direction in which the beam intensity is strong coincides with the longitudinal direction NH. When a slit or elliptical optical system is used, as shown in FIG. 23 (b), at the condensing point, the beam shape is NH in the longitudinal direction of the region on the laser beam incident surface side (see FIG. 23 (a)). ) Has a longitudinal direction NH0 perpendicular to). In the beam intensity distribution in the plane of the beam shape of FIG. 23 (b) (in the plane at the Z direction position of the condensing point), the distribution has a strong intensity in the longitudinal direction NH0, and the direction in which the beam intensity is strong. Consistent with NH0 in the longitudinal direction.

When such a slit or an elliptical optical system is used, the beam shape other than the focusing point has a longitudinal direction, and the beam shape other than the focusing point is the beam shape targeted by the present embodiment. .. That is, a part of the focusing region C targeted by the present embodiment includes a region on the laser beam incident surface side near the focusing point, and the beam shape targeted by the present embodiment is shown in FIG. 23 (a). It is a beam shape shown in.

In the trimming process, the control unit 6 controls the rotation of the stage 2, the irradiation of the laser beam L from the irradiation unit 3, the beam shape, and the movement of the condensing region C. The control unit 6 can execute various controls based on the rotation information (hereinafter, also referred to as “θ information”) regarding the rotation amount of the stage 2. The θ information may be acquired from the driving amount of the driving device that rotates the stage 2, or may be acquired by a separate sensor or the like. 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 located at the position in the 0 ° direction.

The control unit 6 in the irradiation unit 3 based on the θ information in a state where the condensing region C is positioned along the line A (periphery of the effective region R) in the object 11 while rotating the stage 2. By controlling the start and stop of the irradiation of the laser beam L, the peripheral treatment for forming the modified region along the peripheral edge of the effective region R is executed.

The control unit 6 irradiates the removal region E with the laser beam L without rotating the stage 2, and moves the condensing region C of the laser beam L to form a modified region in the removal region E. Execute the removal process.

The control unit 6 rotates the stage 2 and laser light from the irradiation unit 3 so that the pitch of the plurality of modification spots included in the modification region (interval between the modification spots adjacent to the processing progress direction) is constant. At least one of the irradiation of L and the movement of the condensing region C is controlled.

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 from the captured image of the camera for alignment (not shown). The control unit 6 controls the movement of the irradiation unit 3 so that the irradiation unit 3 can move along the X direction to the rotation axis Cx of the stage 2.

Next, an example of trimming will be described. First, the object 11 is placed on the stage 2 so that the first surface 11a is the incident surface of the laser beam L. The second surface 11b side on which the functional element is mounted in the object 11 is protected by adhering a support substrate or a tape material.

Subsequently, trimming is performed. In the trimming process, the control unit 6 executes peripheral processing. Specifically, as shown in FIG. 24A, the condensing region C is positioned along the peripheral edge of the effective region R in the object 11 while rotating the stage 2 at a constant speed. In this state, the start and stop of the irradiation of the laser beam L in the irradiation unit 3 are controlled based on the θ information. As a result, as shown in (b) of FIG. 24 and (c) of FIG. 24, the modified region 12 is formed along the line A (periphery of the effective region R). The modified region 12 formed contains the modified spot and cracks extending from the modified spot.

In the trimming process, the control unit 6 executes the removal process. Specifically, as shown in FIG. 25 (a), the laser beam L is irradiated in the removal region E without rotating the stage 2, and the irradiation unit 3 is moved along the X direction. The condensing region C of the laser beam L moves relative to the object 11 in the X direction. After rotating the stage 2 by 90 °, the laser beam L is irradiated in the removal region E, the irradiation unit 3 is moved along the X direction, and the condensing region C of the laser beam L is directed with respect to the object 11. It moves relative to the X direction.

As a result, as shown in FIG. 25 (b), the modified region 12 is formed along the line extending so as to divide the removal region E into four equal parts when viewed from the Z direction. The modified region 12 formed contains the modified spot and cracks extending from the modified spot. The crack may reach at least one of the first surface 11a and the second surface 11b, or may not reach at least one of the first surface 11a and the second surface 11b. Then, as shown in (a) of FIG. 26 and (b) of FIG. 26, the removal region E is removed with the modified region 12 as a boundary, for example, by using a jig or air. As a result, the semiconductor device 11K is formed from the object 11.

Subsequently, as shown in FIG. 26 (c), the peeled surface 11c of the semiconductor device 11K is subjected to finish grinding or polishing with an 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 is acquired.

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

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

A line A is set as a trimming schedule line on the object 11. Line A is a line scheduled to form the modified region 12. The line A extends in an annular shape 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 region R and the removal region E of the object 11. The line A can be set by the control unit 6. The line A is a virtual line, but it may be a line actually drawn. The line A may be coordinated.

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

Further, the control unit 6 acquires line information regarding the line A. The line information includes information on the line A and information on the moving direction (also referred to as “machining progress direction”) of the movement when the condensing region C is relatively moved along the line A. For example, the processing progress direction is the tangential direction of the line A passing through the light collecting region C located on the line A. The control unit 6 can acquire line information based on an input by a user's operation or communication from the outside.

Further, the control unit 6 relatively moves the condensing region C along the line A so that the longitudinal direction of the beam shape intersects the machining progress direction based on the acquired object information and line information. Determine the longitudinal orientation of the case. Specifically, the control unit 6 determines the orientation of the longitudinal NH in the first orientation and the second orientation based on the object information and the line information. The first orientation is the longitudinal orientation 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 longitudinal orientation of the beam shape when the condensing region C is relatively moved along the second region A2 of the line A. Hereinafter, 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 arcuate region, and as an example, the point where the second crystal orientation K2 and the line A are orthogonal to each other is 0 °, and the point where the first crystal orientation K1 and the line A are orthogonal to each other is 90. When the point between 0 ° and 90 ° on line A is 45 °, the region from 0 ° to 45 °, the region from 90 ° to 135 °, the region from 180 ° to 225 °, And a region from 270 ° to 315 °, the second region A2 is an arcuate region, a region from 45 ° to 90 °, a region from 135 ° to 180 °, and a region from 225 ° to 270 °. And the region from 315 ° to 360 °. In this case, the 45 ° point and the 225 ° point are the points where the third crystal direction K3 orthogonal to the (100) plane and the line A are orthogonal to each other, and the 135 ° point and the 315 ° point. Point is a point where the fourth crystal orientation K4 orthogonal to the (100) plane and the line A are orthogonal to each other.

As described above, the line A includes a plurality of first regions A1 and a plurality of second regions A2 arranged alternately at intervals of 45 ° in a counterclockwise direction. However, the above-mentioned angle range of the first region A1 and the second region A2 can be arbitrarily changed depending on where the point of 0 ° is set. For example, when the point where the first crystal orientation K1 and the line A are orthogonal to each other is set to 0 ° (when the above 90 ° point is set to 0 °), the first region A1 and the second region A2 are described above. The angle range is rotated by 90 ° from the angle range of. Further, when the point of 0 ° is set as described above, the point of 315 °, which is a point rotated by 45 ° clockwise from the point of 0 °, can be paraphrased as a point of −45 °. Further, the point of the boundary (for example, 45 °) between the first region A1 and the second region A2 may be included in either one of the first region A1 and the second region A2, or may be included in both. May be good.

The first region A1 includes a region in which the processing angle described later is 0 ° or more and 45 ° or less, or −90 ° or more and −45 ° or less when the condensing region C is relatively moved along the line A. .. The second region A2 includes a region in which the processing angle described later is 45 ° or more and less than 90 ° or −45 ° or more and less than 0 ° when the condensing region C is relatively moved along the line A.

As shown in FIG. 28 (b), the processing angle α is the angle of the processing progress direction ND with respect to the first crystal orientation K1. The processing angle α is a positive (plus) angle when viewed from the Z direction intersecting the first surface 11a, which is the incident surface of the laser beam L, and a negative (minus) angle toward the clockwise direction. ). The processing angle α can be acquired based on the θ information of the stage 2, the object information, and the line information. When the light collecting region C is relatively moved along the first region A1, it can be recognized as, for example, a case where the processing angle α is 0 ° or more and 45 ° or less or −90 ° or more and −45 ° or less. can. When the light collecting region C is relatively moved along the second region A2, it can be recognized as, for example, a case where the processing angle α is 45 ° or more and 90 ° or less or −45 ° or more and 0 ° or less.

In the first orientation and the second orientation, the machining progress direction ND is closer to one of the first crystal orientation K1 and the second crystal orientation K2, which has a larger angle (one farther away) from the machining progress direction ND. It is the direction of inclination with respect to.

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

The first direction is the direction of the condensing region C when the beam angle β is + 10 ° to + 35 °. The second direction is the direction of the condensing region C when the beam angle β is −35 ° to −10 °. The beam angle β is an angle between the machining progress direction ND and the longitudinal direction NH. The beam angle β is a positive (plus) angle when viewed from the Z direction intersecting the first surface 11a, which is the incident surface of the laser beam L, and a negative (minus) angle toward the clockwise direction. ). The beam angle β can be obtained based on the direction of the condensing region C and the processing progress direction ND.

The control unit 6 controls the start and stop of laser machining on the object 11. The control unit 6 relatively moves the condensing region C along the first region A1 of the line A to form the modified region 12, and also forms the modified region 12 in the region other than the first region A1 of the line A. The first processing process for stopping the formation of the twelve is executed. The control unit 6 relatively moves the condensing region C along the second region A2 of the line A to form the modified region 12, and also forms the modified region 12 in the region other than the second region A2 of the line A. A second processing process for stopping the formation of the twelve is executed.

The formation of the modified region 12 and the switching of its stop by the control unit 6 can be realized as follows. For example, in the irradiation unit 3, the formation of the modified region 12 and the stop of the formation can be switched by switching the start and stop (ON / OFF) of the irradiation (output) of the laser beam L. Specifically, when the laser oscillator is composed of a solid-state laser, the ON / OFF of the Q switch (AOM (acousto-optic modulator), EOM (electro-optical modulator), etc.) provided in the resonator can be switched. By doing so, 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, the output of the semiconductor laser constituting the seed laser and the amplifier (excitation) laser can be switched ON / OFF, so that the irradiation of the laser beam L can be started and stopped at high speed. Can be switched. When the laser oscillator uses an external modulation element, the ON / OFF of the external modulation element (AOM, EOM, etc.) provided outside the resonator can be switched, so that the irradiation of the laser beam L can be turned ON / OFF at high speed. Can be switched.

Alternatively, the formation of the modified region 12 and the switching of its stop by the control unit 6 may be realized as follows. For example, the optical path of the laser beam L may be opened and closed by controlling a mechanical mechanism such as a shutter, and the formation of the modified region 12 and the stop of the formation may be switched. The formation of the modified region 12 may be stopped by switching the laser beam L to the CW light (continuous wave). The modified region 12 is formed by displaying on the liquid crystal layer 76 of the spatial light modulator 7 a pattern that makes the condensing state of the laser beam L unmodifiable (for example, a pattern of a satin pattern that scatters the laser). You may stop it. The formation of the modified region 12 may be stopped by controlling an output adjusting unit such as an attenuator and reducing the output of the laser beam L so that the modified region 12 cannot be formed. By switching the polarization direction, the formation of the modified region 12 may be stopped. The formation of the modified region 12 may be stopped by scattering (skipping) the laser beam L in a direction other than the optical axis to cut the laser beam L.

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

The above-mentioned laser processing apparatus 1 performs the following trimming processing.

In the trimming process, first, the stage 2 is rotated so that the alignment camera is located directly above the alignment target 11n of the object 11 and the camera is in focus on the alignment target 11n, and the irradiation unit on which the camera is mounted is mounted. 3 is moved along the X direction and the Y direction.

Subsequently, an image is taken with an alignment camera. The position of the object 11 in the 0 ° direction is acquired based on the image captured by the camera. The control unit 6 acquires object information and line information based on the captured image of the camera and the input by the user's operation or communication from the outside. The object information includes alignment information regarding the position and diameter of the object 11 in the 0 ° direction. As described above, since the alignment target 11n has a constant relationship in the θ direction with respect to the position in the 0 ° direction, the position in the 0 ° direction can be obtained by obtaining the position of the alignment target 11n from the captured image. The diameter of the object 11 can be obtained based on the image captured by the camera. The diameter of the object 11 may be set by input from the user.

Subsequently, based on the acquired object information and line information, the control unit 6 sets the direction of the light-collecting area C as the direction NH in the longitudinal direction when the light-collecting area C is relatively moved along the line A. Determine the 1st and 2nd orientations.

Subsequently, the stage 2 is rotated to position the object 11 at a position in the 0 ° direction. In the X direction, the irradiation unit 3 is moved along the X direction and the Y direction so that the light collecting region C is located at a predetermined trimming position. For example, the trimming predetermined position is a predetermined position on the line A in the object 11.

Subsequently, the rotation of stage 2 is started. The tracking of the first surface 11a by the distance measuring sensor (not shown) is started. Before starting the tracking of the distance measuring sensor, it is confirmed in advance that the position of the condensing region C is within the length-measurable range of the distance measuring sensor. When the rotation speed of the stage 2 becomes constant (constant speed), the irradiation unit 3 starts irradiating the laser beam L.

By switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 28A, the light is focused along the first region A1 of the line A. The 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 (first processing step). As shown in FIG. 28 (b), when the first processing step is executed, the control unit 6 adjusts the orientation of the condensing region C so as to be in the first orientation. That is, the orientation of the light collecting region C in the first processing step is fixed in the first orientation.

Subsequently, by switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 29 (a), along the second region A2 of the line A. The light collecting region C is relatively moved to form the modified region 12, and the formation of the modified region 12 in regions 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 executed, the control unit 6 adjusts the orientation of the condensing region C so as to be in the second orientation. That is, the orientation of the light collecting region C in the second processing step is fixed in the second orientation.

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

Above, we have explained the knowledge about diagonal crack formation and an example of trimming. Here, an embodiment of laser processing for forming diagonal cracks during trimming processing will be described. FIG. 30 is a diagram showing an object of laser machining according to an embodiment. FIG. 30A is a plan view, and FIG. 30B is a side view. FIG. 31 is a cross-sectional view of the object shown in FIG.

As shown in FIGS. 30 and 31, the object 100 includes the above-mentioned object 11 and the object 11R which is a member different from the object 11. The object 11R is, for example, a silicon wafer. The object 11 includes a plurality of functional elements and includes a device layer 110 formed on the second surface 11b. The object 11R includes a plurality of functional elements, and includes a device layer 110R formed on the first surface 11Ra of the object 11R. The object 11 and the object 11R are attached to each other by arranging the device layer 110 and the device layer 110R so as to face each other and joining them to each other to form the object 100.

Here, a crack 13 extending from the modified region 12 and the modified region 12 is formed in the object 11, and a trimming process is performed to cut off the removed region E of the object 11 with the modified region 12 and the crack 13 as a boundary. .. More specifically, the object 11 has the first portion 15A and the second portion 15B arranged in order from the second surface 11b (opposite surface) side opposite to the first surface 11a which is the incident surface of the laser beam L. including. Then, in the first portion 15A, the modified region 12 is formed so as to form a crack 13 extending diagonally in the Z direction (hereinafter, may be referred to as “diagonal crack”), and in the second portion 15B, the modified region 12 is formed. The modified region 12 is formed so as to form a crack 13 extending along the Z direction (hereinafter, may be referred to as a “vertical crack”). The line R1 in FIG. 31 shows a line where an oblique crack is planned to be formed, and a line R2 shows a line where a vertical crack is planned to be formed.

Therefore, at least when processing the first portion 15A, the above trimming process and the process for causing an oblique crack are used together. That is, when machining the first portion 15A, the angle between the first crystal orientation K1 and the second crystal orientation K2 with respect to the machining progress direction ND is larger than that of the machining progress direction ND. While forming the beam shape so that the longitudinal direction NH is inclined, the modified region 12 and the crack 13 are formed along the line A, and the crack 13 is formed into an oblique crack.

More specifically, when processing the first region A1 of the line A, the laser is formed so as to be the condensing region C of the first orientation Q1 as shown in FIG. 28 (b). When the light L is formed and the second region A2 of the line A is processed, the light L is formed so as to be the light collecting region C of the second shape Q2 in the second direction as shown in FIG. 29 (b). The laser beam L is formed. In the case of performing such processing, the following processing test was performed.

FIG. 32 is a plan view of the object shown in FIG. As shown in FIG. 32, here, from the point of 0 °, which is the intersection of the line A and the second crystal orientation K2, in the line A, the intersection of the line A and the fourth crystal orientation K4 is −45. Regarding the second region A2 up to the point of °, the condensing region C was relatively moved with the machining progress direction ND as the forward direction ND1 and the condensing region C with the machining progress direction ND as the reverse direction ND2. In each case, processing was actually performed and cross-sectional observation was performed. Here, in order to process the second region A2, the condensing region C is the second shape Q2 shown in FIG. 29 (b). Further, the direction CD in which the diagonal crack extends is a direction toward the outside from the center side of the object 11 (see (b) in FIG. 29).

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 NH of the condensing region C with respect to the machining progress direction ND and the oblique crack. When the extending direction CD is on the same side and the machining progress direction ND is the reverse direction ND2 (when the direction of the arrow of the machining progress direction ND is reversed), the longitudinal direction NH with respect to the machining progress direction ND The direction of inclination and the direction CD in which the diagonal crack extends are opposite to each other. The forward direction ND1 is a counterclockwise direction, and the reverse direction ND2 is a clockwise direction.

33 and 34 are cross-sectional photographs showing the processing results. FIG. 33 shows the machining results in the forward direction ND1, and (a) to (d) are points at 0 °, -15 °, -30 °, and −45 °, respectively. It is a cross-sectional photograph. Further, FIG. 34 shows the processing results in the reverse direction ND2, and (a) to (d) are 0 ° points, -15 ° points, -30 ° points, and −45 °, respectively. It is a cross-sectional photograph of a point.

As shown in FIGS. 33 and 34, in the case of machining in the forward direction ND1 where the direction of the longitudinal NH and the direction CD in which the diagonal crack extends are on the same side with respect to the machining progress direction ND, the temperature changes from 0 ° to −45 °. Although good machining results were obtained up to the point, in the machining in the opposite direction ND2 where the direction of NH in the longitudinal direction and the direction CD in which the diagonal crack extends are opposite to the machining progress direction ND, the point is -45 °. (In (d) of FIG. 34, uneven FN extending to the lower surface was generated, and deterioration in quality was confirmed. From this, it was understood that the relationship between the direction of the inclination of the longitudinal NH with respect to the machining progress direction ND and the direction CD in which the diagonal crack extends with respect to the machining progress direction ND affects the machining quality. Based on this understanding, another processing test was conducted.

FIG. 35 is a schematic diagram for explaining the processing test. FIG. 36 is a schematic view showing the relationship between the machining progress direction, the beam shape, and the oblique crack in the machining test. As shown in FIGS. 35 and 36, in this machining test, the direction at which the angle is 45 ° with respect to the (110) plane when viewed from the Z direction is defined as the machining progress direction ND, and the forward direction ND1 and the reverse direction ND2 are defined. For each, processing was performed when the direction CD in which the diagonal crack extends was set to the forward direction CD1 and the case where the direction CD was the reverse direction CD2. That is, the beam shape of the condensing region C is set to the first shape Q1 for a total of four combinations of two ways in the order of the machining progress direction ND and two ways in the forward and reverse directions of the diagonal crack extending direction CD. Processing was performed in the case of the case and the case of the second shape Q2 (a total of eight types of processing).

FIG. 37 is a table showing the results of the processing tests shown in FIGS. 35 and 36. As shown in FIG. 37, when the direction CD in which the diagonal crack extends is set to the positive direction CD1 for a total of eight types of machining, the beam shape of the condensing region C is set to the second shape Q2 and the machining progress direction. Good machining results (in the table of FIG. 37) when the 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. "A") was obtained.

Further, when the direction CD in which the diagonal crack extends is set to the reverse direction CD2 for a total of eight types of machining, the beam shape of the condensing region C is set to the first shape Q1 and the machining progress direction ND is set to the forward direction ND1. Good machining results were obtained when the beam shape of the condensing region C was set to the second shape Q2 and the machining progress direction ND was set to the reverse direction ND2. From this, when machining at least 45 ° points, the order of the machining progress direction ND is adjusted, and the direction of inclination of the longitudinal direction NH of the condensing region C with respect to the machining progress direction ND and the direction in which the oblique crack extends. It was found that good processing results are obtained when the CD is on the same side.

The point of 45 ° is a point where the third crystal orientation K3 orthogonal to the (100) plane and the line A are orthogonal to each other when the point where the second crystal orientation K2 and the line A are orthogonal to each other is 0 °. This is equivalent to the point at −45 °, which is the point where the fourth crystal orientation K4 orthogonal to the (100) plane and the line A are orthogonal to each other.

Based on the above findings, further processing tests were conducted. FIG. 38 is a table showing the results of the processing test. Of the conditions shown in the table of FIG. 38, the condition that the beam shape is the first shape Q1 in the first region A1 and the condition that the beam shape is the second shape Q2 in the second region A2 are processed. Good machining results (evaluation "A" in the table of FIG. 38) under the conditions IR1 and IR2 in which the direction of inclination of the longitudinal direction NH of the condensing region C with respect to the traveling direction ND and the direction CD in which the oblique crack extends are on the same side. Or the evaluation "B") was obtained. The evaluation shown in FIG. 38 is improved in the order of evaluation "A", evaluation "B", evaluation "C", evaluation "D", and evaluation "E" (that is, evaluation "A"). Is the best, and the rating "E" is not the best).

The condition IR1 is to order the machining progress direction ND with respect to the second region A2 from the 0 ° point to the −45 ° point when the point where the first crystal direction K1 and the line A are orthogonal to each other is 0 °. It is a condition that the direction ND1 and the beam shape of the condensing region C are the second shape Q2. Further, the condition IR2 is a machining progress direction with respect to the first region A1 from the point of −45 ° to the point of −90 ° when the point where the first crystal direction K1 and the line A are orthogonal to each other is 0 °. It is a condition that the ND is the reverse direction ND2 and the beam shape of the condensing region C is the first shape Q1.

On the other hand, among the conditions shown in the table of FIG. 38, if the condition is that the beam shape is the first shape Q1 in the first region A1 and the beam shape is the second shape Q2 in the second region A2. The condition IR3 and the condition IR4, in which the direction of inclination of the longitudinal direction NH of the condensing region C with respect to the processing progress direction ND and the direction CD in which the oblique crack extends are not on the same side, are also inferior to the condition IR1 and the condition IR2. Good processing results were obtained except for the point of -45 °. 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 region A1 and the condition IR6 in which the beam shape is the first shape Q1 in the second region A2. In general, good results were not obtained regardless of the order of the machining progress direction ND.

In addition, (a) of FIG. 39 is the evaluation "E" in the table of FIG. 38, (b) of FIG. 39 is the evaluation "D" in the table of FIG. 38, and (c) of FIG. 39 is in the table of FIG. 38. Is an example of a cross-sectional photograph corresponding to the evaluation "C" in FIG. 39, the evaluation "B" in the table of FIG. 38, and the evaluation "A" in the table of FIG. 39 (e). Is. As shown in FIG. 39, the evaluation "A" and the evaluation "B" show good processing results in which the unevenness reaching the lower surface is not formed. Further, the evaluation "C" shows generally good results, although the unevenness reaching the lower surface is slightly generated. On the other hand, in the evaluation "D" and the evaluation "E", the unevenness reaching the lower surface is relatively large, and the results are not good.

According to the results of the machining test shown in FIGS. 38 and 39, the correctness of the findings obtained from the results of the machining test shown in FIG. 37 was confirmed.

In this embodiment, laser processing is performed based on the above knowledge. Here, first, the first portion 15A (see FIG. 31) of the object 11 is processed. That is, by switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 40 (a), along the first region A1 of the line A. The light collecting 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 (second region A2) is stopped (first). processing).

As shown in FIG. 40 (b), in the first machining, the rotation direction of the stage 2 is controlled under the control of the moving section 4 of the control section 6, so that the machining progress direction ND is the reverse direction ND2. It is said that. Further, since the first processing is the processing of the first region A1, the laser beam L is formed by the spatial light modulator 7 under the control of the control unit 6, so that the beam shape of the condensing region C is formed. Is the first shape Q1. Further, here, the direction CD in which the diagonal crack extends is defined as the positive direction CD1 so as to incline in the direction outward from the center of the object 11 with respect to the Z direction toward the second surface 11b (see FIG. 31). To.

The method of forming diagonal cracks here will be specifically explained. That is, in the first processing, as shown in FIG. 41, the position of the condensing region C1 in the Z direction intersecting the first surface 11a, which is the incident surface of the laser beam L1 on the object 11, is set to the first Z position Z1. By relatively moving the condensing region C1 along the line A (X direction) while setting, the modified region (first modified region) 12a and the crack (first crack) 13a extending from the modified region 12a are formed. It is formed on the object 11 (first formation). In this first formation, the position of the light collecting region C1 along the first surface 11a and intersecting the X direction in the Y direction is set to the first Y position Y1.

Further, in the first processing, the position of the condensing region C2 of the laser beam L2 in the Z direction is set to the first surface 11a (incident surface) side of the first Z position Z1 of the condensing region C1 in the first formation. A crack extending from the modified region 12b (second modified region) and the modified region 12b (second) by relatively moving the condensing region C2 along the line A (X direction) while setting the 2Z position Z2. (Crack) 13b is formed (second formation). In this second formation, the position of the condensing region C2 in the Y direction is set to the second Y position Y2 shifted from the first Y position Y1 of the condensing region C1. Further, in the second formation, the beam shape of the condensing region C2 in the YZ plane S including the Y direction and the Z direction is inclined in the direction of the shift at least on the first surface 11a side of the center of the condensing region C2. The laser beam L2 is modulated so as to have an inclined shape (the beam shape of the condensing region C2 when viewed from the Z direction is the first shape Q1). As a result, the crack 13 is formed in the YZ plane S so as to be inclined in the direction of the shift. The control of the beam shape in the YZ plane S is as described in the above-mentioned knowledge about the oblique crack.

Here, also in the first formation, as in the second formation, the beam shape of the condensing region C1 in the YZ plane S including the Y direction and the Z direction is at least first than the center of the condensing region C1. The laser beam L1 is modulated so as to have an inclined shape inclined in the direction of the shift on the surface 11a side (also in this case, the beam shape of the condensing region C1 when viewed from the Z direction is the first shape Q1). .. As a result, as shown in FIG. 41 (b), in the first region A1 of the line A, the crack 13a and the crack 13b are connected and the crack 13 (diagonal crack 13F) extending diagonally over the modified regions 12a and 12b. ) Is formed. The diagonal crack 13F may or may not reach the second surface 11b of the object 11 (it may be appropriately set according to the required processing mode).

The laser beams L1 and L2 are divided into two laser beams L by, for example, displaying a pattern for branching the laser beam L on the spatial light modulator 7 and modulating the laser beam L. Can be generated. In this case, the first formation and the second formation will be carried out at the same time. However, the laser beams L1 and L2 may be different laser beams, 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 beams L1 and L2 corresponding to the condensing regions C of the laser light L, respectively.

On the other hand, in the present embodiment, by switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 42 (a), the second line A The condensing region C is relatively moved along the region A2 to form the modified region 12, and the modified region 12 is formed in the region (first region A1) other than the second region A2 of the line A. Stop (second processing).

As shown in FIG. 42 (b), in the second machining, the rotation direction of the stage 2 is controlled under the control of the moving section 4 of the control section 6, so that the machining progress direction ND is the forward direction ND1. It is said that. That is, between the first machining and the second machining, the forward / reverse of the machining progress direction ND (whether the forward direction ND1 or the reverse direction ND2 is used) is switched. Further, since the second processing is the processing of the second region A2, the laser beam L is formed by the spatial light modulator 7 under the control of the control unit 6, so that the beam shape of the condensing region C is formed. Is the second shape Q2. Further, here, the direction CD in which the diagonal crack extends is defined as the positive direction CD1 so as to incline in the direction outward from the center of the object 11 with respect to the Z direction toward the second surface 11b (see FIG. 31). To.

The method of forming diagonal cracks here will be specifically explained. That is, in the second processing, as shown in FIG. 43 (a), the position of the condensing region C1 in the Z direction intersecting the first surface 11a, which is the incident surface of the laser beam L1 on the object 11, is the second. A crack extending from the modified region (first modified region) 12a and the modified region 12a (first) by relatively moving the condensing region C1 along the line A (X direction) while setting the 1Z position Z1. The crack) 13a is formed on the object 11 (first formation). In this first formation, the position of the light collecting region C1 along the first surface 11a and intersecting the X direction in the Y direction is set to the first Y position Y1.

Further, in the second formation, the position of the condensing region C2 of the laser beam L2 in the Z direction is set to the first surface 11a (incident surface) side of the first Z position Z1 of the condensing region C1 in the first formation. A crack extending from the modified region 12b (second modified region) and the modified region 12b (second) by relatively moving the condensing region C2 along the line A (X direction) while setting the 2Z position Z2. (Crack) 13b is formed (second formation). In this second formation, the position of the condensing region C2 in the Y direction is set to the second Y position Y2 shifted from the first Y position Y1 of the condensing region C1. Further, in the second formation, the beam shape of the condensing region C2 in the YZ plane S including the Y direction and the Z direction is inclined in the direction of the shift at least on the first surface 11a side of the center of the condensing region C2. The laser beam L2 is modulated so as to have an inclined shape (the beam shape of the condensing region C2 when viewed from the Z direction is the second shape Q2). As a result, the crack 13 is formed in the YZ plane S so as to be inclined in the direction of the shift.

Here, also in the first formation, as in the second formation, the beam shape of the condensing region C1 in the YZ plane S including the Y direction and the Z direction is at least first than the center of the condensing region C1. The laser beam L1 is modulated so as to have an inclined shape inclined in the direction of the shift on the surface 11a side (also in this case, the beam shape of the condensing region C1 when viewed from the Z direction is the second shape Q2). .. As a result, as shown in FIG. 43 (b), in the second region A2 of the line A, the crack 13a and the crack 13b are connected and the crack 13 (diagonal crack 13F) extending diagonally over the modified regions 12a and 12b. ) Is formed. The crack 13 may or may not reach the second surface 11b of the object 11 (it may be appropriately set according to the required processing mode). The modulation pattern for making the beam shape an inclined shape is as described above.

That is, the modulation pattern here includes a coma aberration pattern for imparting coma aberration to the laser beam L, and at least in the second formation, the control unit 6 controls the magnitude of coma aberration due to the coma aberration pattern. By doing so, the first pattern control for making the beam shape of the condensing region C2 an inclined shape can be performed. As described above, adding coma to the laser beam L is synonymous with the offset of the spherical aberration correction pattern.

Therefore, the modulation pattern here includes the spherical aberration correction pattern Ps for correcting the spherical aberration of the laser beam L, and in at least the second formation, the control unit 6 is the center of the incident pupil surface 33a of the condenser lens 33. By offsetting the center Pc of the spherical aberration correction pattern Ps in the Y direction, the second pattern control for making the beam shape of the condensing region C2 an inclined shape may be performed.

Alternatively, in the second formation, the control unit 6 makes the beam shape of the condensing region C2 an inclined shape by displaying the modulation pattern asymmetrical with respect to the axis Ax along the X direction on the spatial light modulator 7. The third pattern control for the purpose may be performed. The modulation pattern asymmetric with respect to the axis line Ax may be the modulation patterns PG1 to PG4 including the grating pattern Ga, or the modulation patterns PE including the elliptical patterns Es and Ew (or those including both). May be).

That is, the modulation pattern here includes elliptical patterns Es and Ew for making the beam shape of the condensing region C in the XY plane an elliptical shape having the longitudinal direction in the X direction, and in the second formation, the control unit 6 By displaying the modulation pattern PE on the spatial light modulator 7 so that the intensities of the elliptical patterns Es and Ew are asymmetric with respect to the axis Ax along the X direction, the beam shape of the condensing region C2 is obtained. A fourth pattern control for forming an inclined shape may be performed.

Further, in the second formation, the control unit 6 has a modulation pattern (for example, the above-mentioned Axicon lens pattern PA) for forming a plurality of condensing regions C arranged along the direction of the shift in the YZ plane S. ) May be displayed on the spatial light modulator 7, and the fifth pattern control for making the beam shape of the condensing region C an inclined shape may be performed. The various patterns described above may be arbitrarily combined and superimposed. That is, the control unit 6 can execute the first pattern control to the fifth pattern control in any combination.

The first formation and the second formation may be performed at the same time (multifocal processing) or in sequence (single pass processing). That is, the control unit 6 may perform the second formation after performing the first formation on, for example, the first region A1 of the line A. Alternatively, the control unit 6 causes the spatial light modulator 7 to display a modulation pattern including a branch pattern for branching the laser beam L into the laser beams L1 and L2, so that, for example, the line A set on the object 11 is displayed. The first formation and the second formation may be carried out simultaneously for the first region A1.

Subsequently, in the present embodiment, the second portion 15B (see FIG. 31) of the object 11 is processed. In the second part 15B, the formation of diagonal cracks is not essential, and here vertical cracks are formed. Therefore, the processing of the second portion 15B forms the modified

regions

12c and 12d and the cracks (vertical cracks) 13c and 13d extending from them by the same processing as the trimming processing described above (see FIG. 45). In this case, in the second portion 15B, different machining different from the first machining and the second machining is performed without switching the order of the machining progress direction ND between the first region A1 and the second region A2.

However, in the above-mentioned trimming process, the beam shape is set to the first shape Q1 (first process) during the process of the first region A1 and the second region A2 is processed in order to suppress deterioration of the quality of the trim surface. The beam shape was set to the second shape Q2 (second processing), but in the second portion 15B, the longitudinal direction NH of the condensing region C is inclined along the processing progress direction ND (inclination with respect to the processing progress direction ND). In addition, the condensing region C is continuously moved relative to the entire line A without turning on / off the irradiation of the laser beam L at the boundary between the first region A1 and the second region A2. The modified

regions

12c and 12d and the

cracks

13c and 13d may be formed. That is, in the second portion 15B, different processing different from the first processing and the second processing can be performed. Alternatively, in the second portion 15B, the condensing region C is relatively moved along the first region A1 of the line A without switching the machining progress direction ND, so that the light condensing region C is modified along the first region A1. The first Z processing to form the

quality regions

12c and 12d and the

cracks

13c and 13d extending from the modified

regions

12c and 12d in the Z direction, and the light collection along the second region A2 of the line A. By relatively moving the region C, the modified

regions

12c and 12d are formed along the second region A2, and the second

Z forming cracks

13c and 13d extending from the modified

regions

12c and 12d in the Z direction. Processing and processing may be performed as separate processing. In this case, in the first Z processing and the second Z processing, as in the first processing and the second processing, the light collecting region C has the longitudinal direction NH when viewed from the Z direction, and the longitudinal direction NH is The laser beam L can be formed so as to be inclined with respect to the machining progress direction NDD in a direction approaching one of the first crystal orientation K1 and the second crystal orientation K2 having a larger angle with the machining progress 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 over the entire line A and almost the entire Z direction. In particular, as shown in FIG. 45, in the first portion 15A, the device layer 110 of the object 11 and the device layer 110R of the object 11R are arranged from the first surface 11a to the second surface 11b of the object 11.

Cracks

13a and 13b inclined from the inner position of the joint region toward the outer edge 110e of the joint region are formed. Further, the

cracks

13c and 13d may be divided without being continuous or may be continuous. Further, the cracks 13b and the cracks 13c may be separated without being continuous, or may be continuous.

Subsequently, the removal process is performed in the same manner as the above trimming process. Specifically, the laser beam L is irradiated in the removal region E without rotating the stage 2, the irradiation unit 3 is moved along the X direction, and the condensing region C of the laser beam L is the object 11 It moves relative to the X direction. After rotating the stage 2 by 90 °, the laser beam L is irradiated in the removal region E, the irradiation unit 3 is moved in the X direction along the X direction, and the condensing region C of the laser beam L is the object 11 It moves relative to the X direction.

As a result, as shown in FIG. 46, the modified region 12 and the crack 13 extending from the modified region 12 are formed along the line extending so as to divide the removal region E into four equal parts 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, for example, by using a jig or air. As a result, the semiconductor device 11K is formed from the object 11, and the object 100K including the semiconductor device 11K is obtained.

Subsequently, 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 part of the first portion 15A to be removed is the portion 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 and 12b. When the object 11 is peeled off by etching, the polishing can be simplified. As a result of the above, the semiconductor device 11M is formed, and the object 100M including the semiconductor device 11M is obtained.

The above laser processing according to the present embodiment will be described as a configuration of the laser processing apparatus 1. That is, the laser processing apparatus 1 is for irradiating the object 11 with the laser light L (laser light L1, L2) to form the modified region 12, and at least a stage for supporting the object 11. 2, the irradiation unit 3 for irradiating the laser beam L toward the object 11 supported by the stage 2, and the condensing region C (condensing regions C1 and C2) of the laser beam L with respect to the object 11. It is provided with moving

units

4 and 5 for relative movement, and a control unit 6 for controlling the moving

units

4 and 5 and the irradiation unit 3. The irradiation unit 3 has a spatial light modulator 7 that shapes the laser beam L so that the condensing region C has the longitudinal direction NH when viewed from the Z direction.

Then, the control unit 6 relatively moves the light-collecting area C (light-collecting area C1 and C2) along the first region A1 of the line A by controlling the irradiation unit 3 and the moving

units

4 and 5. As a result, the modified region 12 (modified

regions

12a, 12b) is formed on the object 11 along the first region A1, and the modified region 12 becomes the incident surface of the object 11 with the first surface 11a. The first processing process (the above-mentioned first processing) for forming the oblique crack 13F extending diagonally with respect to the Z direction toward the second surface 11b on the opposite side is executed.

Further, the control unit 6 relatively moves the condensing region C (condensing region C1 and C2) along the second region A2 of the line A by controlling the irradiation unit 3 and the moving

units

4 and 5. As a result, the modified region 12 (modified

regions

12a, 12b) is formed in the object 11 along the second region A2, and the diagonal crack 13F (crack 13a) extending from the modified region 12 toward the second surface 11b is formed. , 13b) The second processing process (the above-mentioned second processing) for forming) is executed.

In the first processing and the second processing, the control unit 6 controls the spatial optical modulator 7 so that the condensing region C has the longitudinal direction NH when viewed from the Z direction, and the longitudinal direction NH. Is inclined with respect to the machining progress direction ND in the direction closer to the larger angle between the first crystal orientation K1 and the second crystal orientation K2 and the machining progress direction ND, which is the movement direction of the condensing region C. As described above, the laser beam L is formed. Further, in the first machining process and the second machining process, the control unit 6 controls the moving

units

4 and 5, so that the direction of inclination of the longitudinal direction NH is set with respect to the machining progress direction ND when viewed from the Z direction. The order of the machining progress direction ND is switched between the first machining process and the second machining process so that the diagonal crack 13F is on the same side as the extending direction.

Subsequently, the laser processing according to the above embodiment will be described as a process of the laser processing method. That is, the laser processing method according to 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 is set on the object 11. By relatively moving the condensing region C (condensing region C1 and C2) along the first region A1 of the line A, the modified region 12 (modifying region 12) is moved to the object 11 along the first region A1. 12a, 12b) is formed, and an oblique crack 13F (diagonal crack 13F) extending diagonally from the modified region 12 toward the second surface 11b opposite to the first surface 11a, which is the incident surface of the object 11, in the Z direction. It has a first processing step (the above-mentioned first processing) for forming

cracks

13a, 13b).

Further, in the laser processing method according to the present embodiment, the condensing region C (condensing region C1 and C2) is relatively moved along the second region A2 of the line A, so that the condensing region C (C1 and C2) is relatively moved along the second region A2. A second processing step of forming a modified region 12 (modified

regions

12a, 12b) on the object 11 and forming an oblique crack 13F (

cracks

13a, 13b) extending from the modified region 12 toward the second surface 11b. Has (the above second processing).

In the first processing step and the second processing step, the light-collecting region C has the longitudinal direction NH when viewed from the Z direction, and the longitudinal direction NH of the light-collecting region C is the first crystal orientation K1 and the second. The laser beam L is formed so that the angle between the crystal orientation K2 and the processing progress direction ND, which is the movement direction of the condensing region C, is larger and the laser beam L is inclined with respect to the processing progress direction ND. Further, 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 the same side as the direction in which the diagonal crack 13F extends with respect to the processing progress direction ND. The order of the traveling direction ND is switched between the first processing step and the second processing step.

As described above, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the object 11 has a crystal structure. Then, here, when the modified region 12 is formed on the object 11 along the first region A1 of the line A that relatively moves the condensing region C of the laser beam L (first processing, first processing). Step) and in the case of forming the modified region 12 in the object 11 along the second region A2 of the line A (second processing process, second processing step), the object is formed from the modified region 12. An oblique crack 13F extending diagonally in the Z direction (direction intersecting the incident surface) toward the second surface 11b (opposite surface) opposite to the first surface 11a (incident surface) of 11 is formed. Therefore, by switching the order of the machining progress direction ND between the first machining process (first region A1) and the second machining process (second region A2), the machining progresses more appropriately according to the crystal structure of the object 11. The direction ND can be set.

In the laser machining apparatus 1 according to the present embodiment, the control unit 6 executes the first machining process and the second machining process on the first portion 15A while switching the order of the machining progress direction ND, and the second portion. Another processing process (separate processing) different from the first processing process and the second processing process may be executed on the 15B. In the separate processing, the control unit 6 controls the irradiation unit 3 and the moving

units

4 and 5 to form the light-collecting region C along the line A while making the order of the processing progress direction ND the same throughout the line A. By moving relative to each other, a modified region 12 and a crack 13 extending from the modified region 12 along the Z direction may be formed in the object 11 along the line A. In this case, even in the second portion 15B, acceleration / deceleration of the relative movement of the condensing region C of the laser beam L is compared with the case where the order of the machining progress direction ND is switched between the first region A1 and the second region A2 of the line A. Time related to is reduced.

Further, in the laser processing apparatus 1 according to the present embodiment, in another processing, the control unit 6 controls the spatial light modulator 7, so that the condensing region C has a longitudinal direction NH when viewed from the Z direction. As such, the laser beam L may be formed so that the longitudinal direction NH of the light collecting region C is along the processing progress direction ND. In this case, in the second portion 15B forming the crack 13 along the Z direction, the inclination of the condensing region C of the laser beam L is set between the processing of the first region A1 and the processing of the second region A2 of the line A. The processing of the control unit 6 is simplified as compared with the case where the laser beam L is formed so as to change.

Further, in the laser machining apparatus 1 according to the present embodiment, the object 11 includes a joining region joined to another member (object 11R), and in the first machining process and the second machining process, the control unit 6 is used. , An oblique crack 13F inclined so as to be directed from the inner position of the joint region toward the outer edge 11e of the joint region may be formed from the first surface 11a to the second surface 11b. In this case, when a part of the object 11 is removed from the object 11 with the diagonal crack 13F as a boundary and the rest of the object 11 remains, the object goes beyond the joint region with other members of the object 11. It is avoided that the rest of the object 11 extends outward.

Further, in the laser processing apparatus 1 according to the present embodiment, the object 11 is orthogonal to the (100) plane, one (110) plane, another (110) plane, and one (110) plane. It has a crystal structure including one crystal orientation K1 and a second crystal orientation K2 orthogonal to another (110) plane, and is supported by stage 2 so that the (100) plane is an incident plane. In the first processing and the second processing, the control unit 6 controls the spatial optical modulator 7 so that the condensing region C has the longitudinal direction NH when viewed from the Z direction, and the collection thereof. Processing progresses in the direction in which the longitudinal direction NH of the optical region C approaches one of the first crystal orientation K1 and the second crystal orientation K2, which has a larger angle between the processing progress direction ND, which is the movement direction of the light collecting region C. The laser beam L is formed so as to be inclined with respect to the direction ND. Therefore, as shown in the above findings, deterioration of the quality of the trim surface is suppressed.

Further, in the laser machining apparatus 1 according to the present embodiment, in the first machining process and the second machining process, the control unit 6 controls the moving

units

4 and 5 to control the moving

units

4 and 5 so as to be in the longitudinal direction NH when viewed from the Z direction. The order of the machining progress direction ND is switched between the first machining process and the second machining process so that the direction of inclination is the same as the direction in which the diagonal crack 13F extends with respect to the machining progress direction ND. Therefore, in both the first region A1 and the second region A2, the direction of inclination of the longitudinal direction NH of the condensing region C with respect to the processing progress direction ND and the extending side of the oblique crack 13F are on the same side. Therefore, as shown in the above findings, the relationship between the direction of NH in the longitudinal direction of the condensing region C and the inclination direction of the oblique crack 13F is a combination in which relatively good quality can be obtained, and quality deterioration is suppressed. .. As described above, in this case, the oblique crack 13F can be formed while suppressing the deterioration of the quality of the trim surface of the object 11.

Further, in the laser processing apparatus 1 according to the present embodiment, the object 11 includes the first portion 15A and the second portion 15B arranged in 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 while switching the order of the machining progress direction ND with respect to the first portion 15A, and the machining progress direction ND with respect to the second portion 15B. By controlling the irradiation unit 3 and the moving

units

4 and 5 without switching, the light-collecting region C is relatively moved along the first region A1 of the line A to the first region A1. The first Z processing (the above-mentioned first Z processing) for forming a modified region 12 in the object 11 along the same direction and forming a crack 13 extending in the Z direction from the modified region 12, and the irradiation unit 3 and movement. By controlling the

parts

4 and 5, the light collecting region C is relatively moved along the second region A2 of the line A to form the modified region 12 in the object 11 along the second region A2. At the same time, the second Z processing process (the above-mentioned second processing) for forming the crack 13 extending from the modified region 12 along the Z direction may be executed as a separate processing. In this case, also for the second portion 15B, the first region A1 and the second region A2 are set in the first region A1 and the second region A2 in the longitudinal direction NH of the condensing region C according to the processing progress direction ND. Compared with the case of switching the order of the processing progress direction ND, the time related to the acceleration / deceleration of the relative movement of the condensing region C of the laser beam L is reduced.

Further, in the laser processing apparatus 1 according to the present embodiment, in the first processing and the second processing, the control unit 6 sets the position of the light collecting region C1 in the Z direction to the first Z position Z1 while setting the line. The first forming process (first formation described above) for forming the crack 13a extending from the modified region 12a and the modified region 12a in the object 11 by relatively moving the condensing region C1 along A, and the Z direction. By moving the condensing region C2 relative to the line A while setting the position of the condensing region C2 about the above to the second Z position Z2 on the first surface 11a side of the first Z position Z1, the modified region 12b And the second forming process (the above-mentioned second forming) for forming the crack 13b extending from the modified region 12b can be performed.

In the first forming process, the control unit 6 sets the position of the light collecting 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 position of the light collecting region C1. , The position of the condensing region C2 in the Y direction is set to the second Y position Y2 shifted from the first Y position Y1, and under the control of the spatial optical modulator 7, the position in the YZ plane S including the Y direction and the Z direction is set. By forming the laser beam L2 so that the shape of the condensing region C2 is inclined in the direction of the shift at least on the first surface 11a side from the center of the condensing region C2, the shift is performed in the YZ surface S. The crack 13b may be formed so as to be inclined in the direction. By doing so, it is possible to suitably form an oblique crack inclined in the Z direction.

Further, in the laser processing apparatus 1 according to the present embodiment, the irradiation unit 3 includes a condenser lens 33 for condensing the laser beam L from the spatial light modulator 7 toward the object 11, and the second formation. In the processing, the control unit 6 forms the laser light L by modulating the laser light L so that the shape of the condensing region C becomes an inclined shape by controlling the modulation pattern displayed on the spatial light modulator 7. May be good. In this case, the laser beam L can be easily formed by using the spatial light modulator 7.

At this time, in the laser processing apparatus 1 according to the present embodiment, the modulation pattern includes a coma aberration pattern for imparting coma aberration to the laser beam L, and in the second forming process, the control unit 6 has coma aberration. By controlling the magnitude of coma aberration due to the pattern, the first pattern control for making the shape of the condensing region C an inclined shape may be performed. According to the findings of the present inventor, 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 region C is inclined in the shift direction on the first surface 11a (incident surface) side of the center Ca of the condensing region C, and is larger than the center Ca of the condensing region C. It is tilted in the direction opposite to the shift direction on the side opposite to the incident surface. Even in this case, it is possible to form an oblique crack 13F that is inclined in the shift direction.

Further, in the laser processing apparatus 1 according to the present embodiment, the modulation pattern includes 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 is the condenser lens 33. By offsetting the center of the spherical aberration correction pattern Ps in the Y direction with respect to the center of the incident pupil surface 33a, the second pattern control for making the shape of the condensing region C an inclined shape may be performed. According to the findings of the present inventor, in this case as well, the shape of the condensing region C in the YZ plane S can be formed in an arc shape as in the case of using the coma aberration pattern, and the diagonal crack 13F inclined in the shift direction. Can be formed.

Further, in the laser processing apparatus 1 according to the present embodiment, in the second forming process, the control unit 6 causes the spatial light modulator 7 to display a modulation pattern asymmetric with respect to the axis along the processing progress direction ND. A third pattern control may be performed to make the shape of the light collecting region C an inclined shape. According to the findings of the present inventor, in this case, the entire shape of the condensing region C in the YZ plane S can be tilted in the shift direction. Even in this case, it is possible to form an oblique crack 13F that is inclined in the shift direction.

Further, in the laser processing apparatus 1 according to the present embodiment, the modulation pattern has the shape of the condensing region C in the XY plane including the X direction and the Y direction intersecting the Y direction and the Z direction, and the X direction is the longitudinal direction. In the second forming process, the control unit 6 spatially photomodulates the modulation pattern so that the intensity of the elliptical pattern is asymmetric with respect to the axis along the X direction. The fourth pattern control for making the beam shape an inclined shape may be performed by displaying the light on the device 7. According to the findings of the present inventor, even in this case, the shape of the condensing region C in the YZ plane S can be formed in an arc shape, and the diagonal crack 13F inclined in the shift direction can be formed.

Further, in the laser processing apparatus 1 according to the present embodiment, in the second forming process, the control unit 6 forms a condensing point CI of a plurality of laser beams L arranged along the shift direction in the YZ plane S. By displaying the modulation pattern for this purpose on the spatial light modulator 7, the fifth pattern control for making the shape of the light-collecting region C including the plurality of light-collecting points CI into an inclined shape may be performed. According to the findings of the present inventor, it is possible to form an oblique crack 13F inclined in the shift direction also in this case.
[Second Embodiment of Laser Machining]

Subsequently, another embodiment of laser processing for forming diagonal cracks during trimming processing will be described. FIG. 48 is a diagram showing an object of laser machining according to an embodiment. As shown in FIG. 48, the object of laser machining according to the present embodiment is the object 11 which is bonded to the object 11R to form the object 100, as in the first embodiment. However, in the present embodiment, the angle ranges of the first region A1 and the second region A2 in the line A are different from those in the first embodiment.

In the first embodiment, as an example, the boundary between the first region A1 and the second region A2 is set to a point of 45 ° or −45 ° where the quality of the trim surface is likely to deteriorate. In the first embodiment, even at the points of 45 ° and −45 ° where quality deterioration is likely to occur, the order and reverse of the machining progress direction ND are adjusted, and when machining the points at 45 ° and −45 °. It was based on the finding that quality deterioration can be suppressed if the direction of inclination of the longitudinal direction NH of the condensing region C with respect to the processing progress direction ND and the direction in which the oblique crack 13F extends are on the same side.

On the other hand, as shown in the table of FIG. 38, for example, when the machining progress direction ND at the time of machining the first region A1 and the second region A2 is set to the forward direction ND1 (first and third from the top). (Refer to the table), the point of -45 ° shows quality deterioration when the beam shape of the condensing region C is the first shape Q1 (see the third table from the top), but when the beam shape of the second shape Q2 is used (see the table). (See the first table from the top) It can be seen that good quality is obtained, and good quality is still obtained at the point of -50 °.

Therefore, even if the machining progress direction ND in the machining of the first region A1 and the second region A2 is unified to the forward direction ND1, the condensing region is used in the machining in the angle range from 0 ° to -50 °. If the beam shape of C is the second shape Q2 and the beam shape of the condensing region C is the first shape Q1 when processing in an angle range of about -50 ° to -90 °, all angles. Good processing quality can be obtained in the range. In fact, referring to the table of FIG. 49, it can be seen that good processing quality can be obtained in all angle ranges by using the condition IR7 and the condition IR8 together.

Further, for example, when the machining progress direction ND at the time of machining the first region A1 and the second region A2 is set to the reverse direction ND2 (see the second and fourth tables from the top), the temperature is −45 °. Contrary to the example of the forward direction D1, the point shows that the quality is deteriorated when the beam shape of the condensing region C is the second shape Q2 (see the second table from the top), and when the beam shape is the first shape Q1. (See the fourth table from the top) It can be seen that good quality is obtained, and good quality is still obtained at the point of −40 °.

Therefore, even if the machining progress direction ND in the machining of the first region A1 and the second region A2 is unified to the reverse direction ND2, the condensing region is used in the machining in the angle range from 0 ° to -40 °. If the beam shape of C is the second shape Q2 and the beam shape of the condensing region C is the first shape Q1 during processing in an angle range of about -40 ° to -90 °, all angles are set. Good processing quality can be obtained in the range. In fact, referring to the table of FIG. 50, it can be seen that good processing quality can be obtained in all angle ranges by using the condition IR9 and the condition IR10 together.

That is, the longitudinal direction NH of the condensing region C is inclined with respect to the machining progress direction ND in the direction closer to one of the first crystal orientation K1 and the second crystal orientation K2, which has a larger angle with the machining progress direction ND. On the premise that the laser beam L is formed so as to be performed, the order of the processing progress direction is the same for the processing of the first region A1 (the above-mentioned first processing) and the processing of the second region A2 (the above-mentioned second processing). In the case of, one of the first region A1 and the second region A2 where the direction of inclination of the longitudinal direction NH is the same side as the side where the oblique crack 13F extends with respect to the machining progress direction ND is 45 °. If the boundary between the first region A1 and the second region A2 is set so as to include (the point of −45 ° in the above example), good processing quality can be obtained in all the angle ranges.

The laser processing according to this embodiment is performed based on the above knowledge. That is, in the laser machining according to the present embodiment, as shown in FIG. 48, the boundary Ks between the first region A1 and the second region A2 is inclined in the longitudinal direction NH at an angle with respect to the machining progress direction ND. One of the sides on which the crack 13F extends is set to include a 45 ° point (-45 ° point in the above example). In the illustrated example, the machining progress direction ND is set to the forward direction ND1, and the boundary Ks is set so that the second region A2 includes a point at 45 °.

In particular, here, as compared with the first embodiment, the first region A1 is reduced by about 5 ° to form an arc of about 40 ° from 0 ° to about 40 °, and the second region A2 is about 5 Since the arc is expanded by ° to form an arc of about 50 ° from 40 ° to 90 °, the second region A2 is longer than the first region A1 by about 10 °. The machining of the first region A1 and the second region A2 is the above-mentioned first machining and second machining (further, further, except that the machining progress direction ND is unified to the forward direction ND1 (or the reverse direction ND2). It is carried out in the same manner as the first formation and the second formation).

units

4 and 5 for relative movement, and a control unit 6 for controlling the moving

units

4 and 5. As a result, the modified region 12 (modified

regions

12a, 12b) is formed on the object 11 along the first region A1, and the modified region 12 becomes the incident surface of the object 11 with the first surface 11a. The first processing (the above-mentioned first processing) for forming diagonal cracks 13F (

cracks

13a, 13b) extending diagonally in the Z direction toward the second surface 11b on the opposite side is executed.

units

4 and 5. As a result, the modified region 12 (modified

regions

In the first processing and the second processing, the control unit 6 controls the spatial optical modulator 7 so that the longitudinal direction NH of the condensing region C is the first crystal orientation K1 and the second crystal orientation K2. The laser beam L is formed so as to be inclined with respect to the machining progress direction ND so that the angle between the light collecting region C and the machining progress direction ND is large and the angle is closer to one side, and the first machining process is performed. And the second processing process, the order and reverse of the processing progress direction ND are the same.

Then, the point where the second crystal direction K2 and the line A are orthogonal to each other is 0 °, the point where the first crystal direction K1 and the line A are orthogonal to each other is 90 °, and the point between 0 ° and 90 ° in the line A is set. When the point is set to 45 °, of the first region A1 and the second region A2, the direction of inclination of the longitudinal direction NH is the same as the side where the diagonal crack 13F extends with respect to the machining progress direction ND when viewed from the Z direction. The boundary Ks between the first region A1 and the second region A2 is set so that one of them includes a point of 45 °.

cracks

13a, 13b).

regions

12a, 12b) on the object 11 and forming an oblique crack 13F (

cracks

In the first processing step and the second processing step, the light-collecting region C has the longitudinal direction NH when viewed from the Z direction, and the longitudinal direction NH of the light-collecting region C is the first crystal orientation K1 and the second. The laser beam L is formed so that the angle between the crystal orientation K2 and the processing progress direction ND, which is the movement direction of the condensing region C, is larger and the laser beam L is inclined with respect to the processing progress direction ND. , The order of the machining progress direction ND is the same in the first machining step and the second machining step.

As described above, in the laser machining apparatus 1 and the laser machining method according to the present embodiment, the object 11 has a (100) plane, one (110) plane, another (110) plane, and one. It has a crystal structure including a first crystal orientation K1 orthogonal to the (110) plane and a second crystal orientation K2 orthogonal to another (110) plane. Then, here, when the modified region 12 is formed on the object 11 along the first region A1 of the line A that relatively moves the condensing region C of the laser beam L (first processing, first processing). Step) and in the case of forming the modified region 12 in the object 11 along the second region A2 of the line A (second processing process, second processing step), the light collecting region C The laser beam L is such that the longitudinal direction NH is inclined with respect to the processing progress direction ND so that the angle between the first crystal direction K1 and the second crystal direction K2 and the processing progress direction ND is larger and approaches one of them. Is molded. Therefore, as shown in the above findings, deterioration of the quality of the trim surface is suppressed.

On the other hand, in the laser machining apparatus 1 and the laser machining method according to the present embodiment, the reforming region 12 is placed in the first machining process and the second machining process (the same applies to the first machining step and the second machining step (the same applies hereinafter)). To form an oblique crack 13F extending diagonally in the Z direction (direction intersecting the incident surface) toward the second surface 11b (opposite surface) opposite to the first surface 11a (incident surface) of the object 11. .. Therefore, it is necessary to consider the relationship between the extending direction of the oblique crack 13F and the direction of NH in the longitudinal direction of the condensing region C. In particular, when machining a point at 45 °, if the direction of NH in the longitudinal direction of the condensing region C and the tilting direction of the oblique crack 13F are opposite to each other with respect to the machining progress direction ND, the trim surface Quality deterioration is likely to occur.

On the other hand, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the boundary Ks between the first region A1 and the second region A2 is the longitudinal length of the first region A1 and the second region A2. The direction of inclination of the direction NH is set to be the same side as the side on which the diagonal crack 13F extends with respect to the machining progress direction ND, and one of them includes a point of 45 °. In other words, of the first region A1 and the second region A2, the direction of NH in the longitudinal direction of the condensing region C and the inclination direction of the oblique crack 13F are opposite to each other in the machining progress direction ND. Does not reach the 45 ° point on line A. Therefore, quality deterioration is suppressed. As described above, according to the laser processing apparatus 1 and the laser processing method according to the present embodiment, it is possible to form the oblique crack 13F while suppressing the deterioration of the quality of the trim surface of the object 11.

Further, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the order of the processing progress direction ND is the same in the first processing process and the second processing process. Therefore, the time required for accelerating / decelerating the relative movement of the condensing region C of the laser beam L is reduced as compared with the case where the order of the processing progress direction ND is switched between the first processing process and the second processing process.

Further, in the laser processing apparatus 1 according to the present embodiment, among the first region A1 and the second region A2, the diagonal crack 13F extends in the direction of inclination of NH in the longitudinal direction with respect to the processing progress direction ND when viewed from the Z direction. One that is on the same side as the side may be longer than the other. In this way, the lengths of the first region A1 and the second region A2 may be set differently.

Further, in the laser machining apparatus 1 according to the present embodiment, the control unit 6 executes the first machining process and the second machining process on the first portion 15A while making the order of the machining progress direction ND the same. A separate processing (separate processing) different from the first processing and the second processing may be executed on the second portion 15B. In the separate processing, the control unit 6 controls the irradiation unit 3 and the moving

units

4 and 5 to relatively move the condensing region C while making the order of the processing progress direction ND the same throughout the line A. , The modified region 12 and the crack 13 extending from the modified region 12 along the Z direction may be formed in the object 11 along the line A. In this case, even in the second portion 15B, acceleration / deceleration of the relative movement of the condensing region C of the laser beam L is compared with the case where the order of the machining progress direction ND is switched between the first region A1 and the second region A2 of the line A. Time related to is reduced.

Further, in the laser processing apparatus 1 according to the present embodiment, in the separate processing, the spatial light modulator 7 is controlled so that the condensing region C has the longitudinal direction NH when viewed from the Z direction, and The laser beam L may be formed so that the longitudinal direction NH of the light collecting region C is along the processing progress direction ND. In this case, in the second portion 15B forming the crack 13 along the Z direction, the inclination of the condensing region C of the laser beam L is set between the processing of the first region A1 and the processing of the second region A2 of the line A. The processing of the control unit 6 is simplified as compared with the case where the laser beam L is formed so as to change.

Further, in the laser machining apparatus 1 according to the present embodiment, as a separate machining process, the irradiation section 3 and the moving

sections

4 and 5 are controlled for the second portion 15B without switching the machining progress direction ND. By relatively moving the condensing region C along the first region A1 of the line A, the modified region 12 is formed on the object 11 along the first region A1 and the modified region 12 is formed. By controlling the first Z processing (the above-mentioned first Z processing) for forming the crack 13 extending in the Z direction from the irradiation portion 3 and the moving

portions

4 and 5, the second region A2 of the line A can be formed. By relatively moving the condensing region C along the second region A2, the modified region 12 is formed in the object 11 along the second region A2, and the crack 13 extending from the modified region 12 in the Z direction is formed. The second Z processing process (the above-mentioned second process) may be executed as a separate processing. In this case, also for the second portion 15B, the first region A1 and the second region A2 are set in the longitudinal direction NH of the condensing region C in the first region A1 and the second region A2 according to the processing progress direction ND. Compared with the case of switching the order of the processing progress direction ND, the time related to the acceleration / deceleration of the relative movement of the condensing region C of the laser beam L is reduced.

In the first forming process, the control unit 6 sets the position of the light collecting 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 position of the light collecting region C1. , The position of the condensing region C2 in the Y direction is set to the second Y position Y2 shifted from the first Y position Y1, and under the control of the spatial optical modulator 7, the position in the YZ plane S including the Y direction and the Z direction is set. By forming the laser beam L2 so that the shape of the condensing region C2 is inclined in the direction of the shift at least on the first surface 11a side from the center of the condensing region C2, the shift is performed in the YZ surface S. Diagonal cracks 13F may be formed so as to be inclined in the direction. By doing so, it is possible to suitably form an oblique crack inclined in the Z direction.

Further, in the laser processing apparatus 1 according to the present embodiment, in the second forming process, the control unit 6 forms a condensing point CI of a plurality of laser beams L arranged along the shift direction in the YZ plane S. By displaying the modulation pattern for this purpose on the spatial light modulator 7, the fifth pattern control for making the shape of the light-collecting region C including the plurality of light-collecting points CI into an inclined shape may be performed. According to the findings of the present inventor, it is possible to form an oblique crack 13F inclined in the shift direction also in this case.
[Modification example]

Although one aspect of the laser processing apparatus and the laser processing method has been described above, one aspect of the present disclosure is not limited to the above aspect and can be modified.

For example, in the above example, the object 100 (bonded wafer) formed by bonding the object 11 and the object 11R is mentioned, but the target of laser processing is not limited to such a bonded wafer, and is simply a single object. It may be an object such as one wafer.

Further, in the example shown in FIG. 45, there is a case where two modified

regions

12a and 12b are formed by using the two condensing regions C1 and C2 with respect to the first portion 15A. In this case, when forming the oblique crack 13F, at least the beam shape in the YZ surface S of the condensing region C2 on the first surface 11a side was controlled. However, when a plurality of sets of modified

regions

12a and 12b are formed with respect to the first portion 15A, when the modified

regions

12a and 12b on the second surface 11b side (object 11R side) are formed. At least, the beam shape in the YZ surface S of the condensing region C2 on the first surface 11a side may be controlled.

Further, in the above embodiment, a vertical crack was formed with respect to the second portion 15B of the object 11. However, the second portion 15B of the object 11 may also form an oblique crack in the same manner as the first portion 15A.

Further, in the laser processing according to the first embodiment, the first processing, which is the processing of the first region A1 of the line A, and the second processing, which is the processing of the second region A2, are performed at 0 °, 45 °, and so on. An example is described in which the laser is set on the GUI so as to be switched at 45 ° intervals such as 90 °, and the actual laser ON / OFF is also performed at the same angle. However, in an actual device, there is a case where the laser ON / OFF delay is delayed by several hundred msec from the setting. That is, it is not limited to the case where the laser is strictly turned on and off at the boundary between the first region A1 and the second region A2.

Further, in order to reduce the amount of the formation position deviation of the reforming region 12 due to the above-mentioned causes, the control unit 6 corrects the delay time of turning on / off the laser in advance, and the correction parameter for turning the laser on / off early. You may have. In this case, the deviation of the formation position of the modified region 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 is about 2.617 mm per 1 °, so that the deviation in this case can be contained within 1 °.

As shown in the results of FIG. 38 and the like, it is confirmed that the switching point between the first region A1 and the second region A2 has a processing quality margin of about ± 5 °. Therefore, the setting of the switching point may be intentionally shifted as long as it is within the quality margin such as ° ± 5 °, 45 ° ± 5 °, 90 ° ± 5 °.

Further, in the above embodiment, for example, by turning the laser on and off, the modified region 12 is formed so as to be annular when viewed from the Z direction, but strictly speaking, it is partially turned on and off at the position where it is turned on and off. The modified regions 12 may overlap (for example, about several hundred μm), or conversely, there may be regions where the modified regions 12 are not partially formed (for example, about several hundred μm). In order to prevent the quality from deteriorating due to these influences, there is a case where a plurality of stages are processed by giving the effects of the formation of diagonal cracks and the above-mentioned first processing and second processing to a plurality of stages.

Further, in actual processing, a run-up distance is required until the relative movement speed of the condensing region C becomes constant, so switching between the forward direction ND1 and the reverse direction ND2 includes the run-up. At the time of approaching, the laser is turned off, and after the speed becomes constant, the laser is turned on at the switching point. The number of revolutions during the run-up depends on the performance of the device. Further, the autofocus may be adjusted so that the autofocus is followed from the run-up and the overshoot does not occur when the modified region is formed.

Further, the second embodiment also has the same switching accuracy as the above example, but the switching points such as the 45 ° point and the 135 ° point are as shown in the table of FIG. 49. At least no switching is performed at the −45 ° point, and the switching is centered on the −50 ° point (in the example of the table in FIG. 50, the switching is centered on the −40 ° point). At that time, the allowable margin of deviation is about ± 2 ° as an example, but it may be increased to about ± 4 ° depending on the beam shape (further increasing the ellipticity). On the other hand, it is not necessary to shift the switching point between 0 ° and 90 °, but it may be shifted within a range of, for example, ± 4 ° according to the quality margin.
[Third Embodiment of Laser Machining]

Subsequently, another embodiment of laser processing for forming diagonal cracks during trimming processing will be described. First, for example, the knowledge regarding a new problem when the laser processing according to the first embodiment and the second embodiment is performed will be described. That is, the present inventor specifies the line A that relatively moves the condensing region C even when the direction of the longitudinal direction NH of the beam shape is set as described above based on the processing progress direction ND and the crystal structure. It was discovered that there is room for further suppression of quality deterioration of the trim surface in this area.

That is, the object 11 has a (100) plane, one (110) plane, another (110) plane, a first crystal orientation K1 orthogonal to one (110) plane, and another (110). When the crystal structure includes the second crystal orientation K2 orthogonal to the plane, the point at which the line A and the second crystal orientation K2 are orthogonal is set to 0 °, and the line A and the first crystal orientation K1 are orthogonal to each other. The point to be crystallized is 90 °, and the point between 0 ° and 90 ° on the line A is 45 °.

At this time, for example, as shown in FIGS. 38, 49, and 50, in the region near 45 ° in the line A, good machining results (evaluation " It is understood that although B ") is obtained, there is room for improvement so that better processing results (evaluation" A ") can be obtained.

On the other hand, the present inventor sets a region including 45 ° in the line A separately from the first region A1 and the second region A2, and in the region, the direction of the longitudinal direction NH of the beam shape is the machining progress direction. It was found that the quality of the trimmed surface becomes better when it is in line with ND. This point will be described in more detail.

FIG. 51 is a diagram showing an object according to the present embodiment. The object 11 shown in FIG. 51 is the same as the first embodiment and the second embodiment described above, but the setting of the line A is different. That is, in the present embodiment, the line A is a region between the first region A1 including 0 °, the second region A2 including 90 °, and the first region A1 and the second region A2, and is 45 °. The arc-shaped third region A3 including the above.

Here, as an example, the first region A1 includes a region from 0 ° to 40 °, a region from 90 ° to 130 °, a region from 180 ° to 220 °, and a region from 270 ° to 310 °. The second region A2 includes a region from 50 ° to 90 °, a region from 140 ° to 180 °, a region from 230 ° to 270 °, and a region from 320 ° to 360 °. The third region A3 includes a region from 40 ° to 50 °, a region from 130 ° to 140 °, a region from 220 ° to 230 °, and a region from 310 ° to 320 °. That is, here, a third region A3 having a width of 10 ° is interposed between the first region A1 and the second region A2 with an interval of 90 °.

As in the case described above, the above-mentioned angle range of the first region A1, the second region A2, and the third region A3 can be arbitrarily changed depending on where the point of 0 ° is set. For example, when the point where the first crystal orientation K1 and the line A are orthogonal to each other is set to 0 ° (when the above 90 ° point is set to 0 °), the first region A1, the second region A2, and the first region A2. The three regions A3 are an angle range rotated by 90 ° from the above angle range. Further, when the point of 0 ° is set as described above, the point of 315 °, which is a point rotated by 45 ° clockwise from the point of 0 °, can be paraphrased as a point of −45 °. Further, the boundary points of the first region A1, the second region A2, and the third region A3 may be included in any one of the first region A1, the second region A2, and the third region A3. , May be included in two adjacent two of them.

The first region A1 and the second region A2 are subjected to the first processing and the second processing in the same manner as in the first embodiment and the second embodiment, and the third region A3 is different from these processings. Perform the third processing. As shown in FIG. 52, in the third processing, the trimming processing is performed while forming diagonal cracks as in the first processing and the second processing, but at this time, the longitudinal direction NH of the condensing region C of the laser beam L is performed. Is the third shape Q3 along the processing progress direction ND, and the laser beam L is formed.

As a result, as shown in FIG. 53, better machining results (evaluation "A") can be obtained in the third region A3 extending from -40 ° to -50 ° regardless of the order of the machining progress direction ND. It is. Note that FIG. 53 is a table showing an actual processing result (quality of the trim surface) in a state where the longitudinal direction of the light collecting region of the laser beam is along the processing progress direction. In this embodiment, laser processing is performed based on the above findings. Subsequently, the laser processing according to the third embodiment will be described.

In the third embodiment, first, the first portion 15A (see FIG. 31) of the object 11 is processed. That is, the first processing is carried out in the same manner as in the first embodiment. More specifically, as shown in FIG. 54, first, while rotating the stage 2, the control unit 6 switches ON / OFF of the irradiation of the laser beam L along the first region A1 of the line A. Therefore, the condensing region C is relatively moved to form the modified region 12, and the modified region 12 in the regions other than the first region A1 (second region A2 and third region A3) of the line A is formed. Stop forming (first processing).

In the first machining, the rotation direction of the stage 2 is controlled under the control of the moving section 4 of the control section 6, so that the machining progress direction ND is set to the reverse direction ND2. Further, since the first processing is the processing of the first region A1, the laser beam L is formed by the spatial light modulator 7 under the control of the control unit 6, so that the beam shape of the condensing region C is formed. Is the first shape Q1 (see (b) in FIG. 40). Further, here, the direction CD in which the diagonal crack extends is defined as the positive direction CD1 so as to incline in the direction outward from the center of the object 11 with respect to the Z direction toward the second surface 11b (see FIG. 31). To. The method of forming an oblique crack is the same as that of the first embodiment.

Subsequently, in the third embodiment, by switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 54, the second region A2 of the line A The condensing region C is relatively moved along the line A to form the modified region 12, and the modified region 12 in regions other than the second region A2 of the line A (first region A1 and third region A3). Stops the formation of (second processing).

In the second machining, the rotation direction of the stage 2 is controlled under the control of the moving section 4 of the control section 6, so that the machining progress direction ND is set to the forward direction ND1. That is, between the first machining and the second machining, the forward / reverse of the machining progress direction ND (whether the forward direction ND1 or the reverse direction ND2 is used) is switched. Further, since the second processing is the processing of the second region A2, the laser beam L is formed by the spatial light modulator 7 under the control of the control unit 6, so that the beam shape of the condensing region C is formed. Is the second shape Q2 (see (b) in FIG. 42). Further, here, the direction CD in which the diagonal crack extends is defined as the positive direction CD1 so as to incline in the direction outward from the center of the object 11 with respect to the Z direction toward the second surface 11b (see FIG. 31). To. The method of forming an oblique crack is the same as that of the first embodiment.

Subsequently, in the third embodiment, by switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 54, the third region A3 of the line A The condensing region C is relatively moved along the line A to form the modified region 12, and the modified region 12 in regions other than the third region A3 of the line A (first region A1 and second region A2). Stops the formation of (third processing).

In the third machining, the rotation direction of the stage 2 is maintained from the second machining under the control of the moving section 4 of the control section 6, so that the machining progress direction ND is maintained in the forward direction ND1. Further, since the third processing is the processing of the third region A3, the laser beam L is formed by the spatial light modulator 7 under the control of the control unit 6, so that the beam shape of the condensing region C is formed. Is the third shape Q3 (see FIG. 52). Further, here, the direction CD in which the diagonal crack extends is defined as the positive direction CD1 so as to incline in the direction outward from the center of the object 11 with respect to the Z direction toward the second surface 11b (see FIG. 31). To. The method of forming an oblique crack is the same as that of the first embodiment. That is, in the third processing, the first formation and the second formation for forming diagonal cracks can be performed in the same manner as in the first processing and the second processing.

Here, the third processing of the third region A3 is performed following the second processing of the second region A2. As a result, it is not necessary to temporarily stop the rotation of the stage 2 to reverse the rotation, and it is possible to shorten the time required for accelerating / decelerating the rotation of the stage 2. In the third processing of the third region A3, the beam shape of the condensing region C is set so that the longitudinal direction NH thereof follows the processing progress direction ND. Therefore, regardless of whether the machining progress direction ND is the forward direction ND1 or the reverse direction ND2, similarly good machining results (evaluation “A”) can be obtained (see FIG. 53).

Therefore, in the third machining, the order of the machining progress direction ND is not limited. However, the order of the machining progress direction ND in the third machining is continuous with the third machining of the first machining and the second machining from the viewpoint of shortening the time related to the acceleration / deceleration related to the relative movement of the condensing region C. It can be the same as the order and reverse of the processing progress direction ND on the one hand.

That is, when the third processing is performed after the second processing as described above, or when the second processing is performed after the third processing, the order of the processing progress direction ND in the third processing is reversed. As with the second processing, the forward direction ND1 can be used. Alternatively, when the third processing is performed after the first processing or when the first processing is performed after the third processing, the order of the processing progress direction in the third processing is the same as that of the first processing. It can be ND2 in the reverse direction.

Subsequently, in the third embodiment, the second portion 15B (see FIG. 31) of the object 11 is processed. The processing of the second portion 15B can be performed in the same manner as in the first embodiment and the second embodiment. That is, when processing the second portion 15B, the above-mentioned separate processing (for example, first Z processing and second Z processing) can be performed.

By the above processing, the modified region 12 and the crack 13 are formed in the object 11 over the entire line A and substantially over the entire Z direction. In particular, in the first portion 15A, as the object 11 moves from the first surface 11a to the second surface 11b, the device layer 110 of the object 11 and the device layer 110R of the object 11R are located inside the junction region.

Cracks

13a and 13b inclined toward the outer edge 110e of the joint region are formed.

Subsequently, as in the first embodiment and the second embodiment, the crack 13 extending from the modified region 12 and the modified region 12 along the line extending so as to divide the removal region E into four equal parts when viewed from the Z direction. Is formed, and the removal region E is removed with the modified region 12 as a boundary. As a result, the semiconductor device 11K is formed from the object 11, and the object 100K including the semiconductor device 11K is obtained. Then, by grinding the semiconductor device 11K from the first surface 11a side, the semiconductor device 11M is formed, and the object 100M including the semiconductor device 11M is obtained.

The laser processing according to the above third embodiment will be described as a configuration of the laser processing apparatus 1. Here, the parts that overlap with the first embodiment and the second embodiment will also be described. That is, the laser processing apparatus 1 is for irradiating the object 11 with the laser light L (laser light L1, L2) to form the modified region 12, and at least a stage for supporting the object 11. 2, the irradiation unit 3 for irradiating the laser beam L toward the object 11 supported by the stage 2, and the condensing region C (condensing regions C1 and C2) of the laser beam L with respect to the object 11. It is provided with moving

units

4 and 5 for relative movement, and a control unit 6 for controlling the moving

units

4 and 5. As a result, the modified region 12 (modified

regions

units

4 and 5. As a result, the modified region 12 (modified

regions

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 condensing region C is the first crystal orientation K1 and the second crystal orientation K2. The laser beam L is formed so as to be inclined with respect to the machining progress direction ND so that the angle between the light collection region C and the machining progress direction ND, which is the movement direction, is large and approaches one side. Further, in the first machining process and the second machining process, the control unit 6 controls the moving

units

In line A, the point where the second crystal orientation K2 and the line A are orthogonal to each other is 0 °, the point where the first crystal orientation K1 and the line A are orthogonal to each other is 90 °, and 0 ° and 90 ° in the line A. When the point between them is 45 °, the region between the first region A1 including 0 °, the second region A2 including 90 °, and the first region A1 and the second region A2 is 45 °. Includes an arcuate third region A3 and.

Then, the control unit 6 relatively moves the condensing region C along the third region A3 of the line A by controlling the irradiation unit 3 and the moving

units

4 and 5, thereby moving to the third region A3. A third processing process (the above-mentioned third processing) for forming a modified region 12 in the object 11 along the same line and forming an oblique crack extending from the modified region 12 toward the second surface 11b is executed.

In this third processing, the control unit 6 controls the spatial light modulator 7 to form the laser beam L so that the longitudinal direction NH of the condensing region C is along the processing progress direction ND. In particular, here, in the third processing process, the control unit 6 controls the moving

units

4 and 5 to reverse the order of the processing progress direction ND of the light collecting region C in the first processing process and the second processing process. It is the same as the order of the machining progress direction ND in one of the processes executed continuously with the third machining process.

Subsequently, the laser processing according to the third embodiment will be described as a process of the laser processing method. That is, the laser processing method according to the present embodiment is a laser processing method for irradiating an object 11 with laser light L (laser light L1, L2) to form a modified region 12 (modified

regions

12a, 12b). The first region A1 is obtained by relatively moving the condensing region C (condensing region C1 and C2) of the laser beam L along the first region A1 of the line A set on the object 11. A modified region 12 is formed in the object 11 along the above line, and diagonal cracks 13F (

cracks

13a, 13b) extending diagonally in the Z direction from the modified region 12 toward the second surface 11b of the object 11 are formed. It has a first processing step of forming (the first processing described above).

Further, in the laser processing method according to the present embodiment, the light collecting region C is relatively moved along the second region A2 of the line A, so that the modified region 12 is formed on the object 11 along the second region A2. A second processing step of forming an oblique crack 13F extending from the modified region 12 toward the second surface 11b is provided.

In the first processing step and the second processing step, the order of the processing progress direction ND, which is the moving direction of the condensing region C, is switched between the first processing step and the second processing step.

On the other hand, in the laser processing method according to the present embodiment, the light collecting region C is relatively moved along the third region A3 of the line A, so that the modified region 12 is formed on the object 11 along the third region A3. It has a third processing step (the above-mentioned third processing) of forming an oblique crack 13F extending from the modified region 12 toward the second surface 11b.

Then, in the third processing step, the laser beam L is formed so that the longitudinal direction NH of the condensing region C is along the processing progress direction ND.

As described above, according to the laser processing apparatus 1 and the laser processing method according to the present embodiment, the first processing and the second processing are performed in the same manner as in the first embodiment, so that the same effect as in the first embodiment can be obtained. It is possible to play. Further, according to the laser processing apparatus 1 and the laser processing method according to the present embodiment, in the third processing, the laser beam L is formed so that the longitudinal direction NH of the condensing region C is along the processing progress direction ND. Therefore, as shown in the above findings, the quality of the trimmed surface in the region including the 45 ° point is better.

Further, in the laser processing apparatus 1 according to the present embodiment, in the third processing, the control unit 6 controls the moving

units

4 and 5, so that the order of the processing progress direction ND of the condensing region C is first. It can be the same as the order of the machining progress direction ND in one of the machining processes and the second machining process, which is continuously executed with the third machining process. In this case, it is possible to shorten the time required for acceleration and deceleration for relative movement of the light collecting region C and suppress tact reduction.

In the third processing, the longitudinal direction NH of the condensing region C is not limited to the case where the longitudinal direction NH exactly matches the processing progress direction ND, and the longitudinal direction NH is not limited to the case where the longitudinal direction NH exactly matches the processing progress direction ND. This includes the case where the inclination is about 6 ° with respect to the machining progress direction ND. Further, the angle range of the third region A3 is not limited to 40 ° to 50 °, and can be arbitrarily selected from a range of less than about 45 ° ± 10 °.

Further, between one processing process (for example, the third processing process) and another process (second processing process in the above example), the irradiation of the laser beam L is turned off and the stage 2 is rotated. There may be a sustained time (ie, the idling time at which stage 2 idles). In this case, within this idling time, the control unit 6 changes the modulation pattern displayed on the spatial light modulator 7 into the shape of the light collecting region C (for example, the third shape Q3). It is possible to execute a process of switching to a modulation pattern for shaping.

In addition, with respect to the laser processing apparatus 1 and the laser processing method according to the third embodiment, the configurations of the above-mentioned first embodiment and the second embodiment, and the modifications according to the first embodiment and the second embodiment are also made. Each configuration of the example can be arbitrarily selected and adopted.
[Fourth Embodiment of Laser Machining]

Subsequently, another embodiment of laser processing for forming diagonal cracks during trimming processing will be described. As described above, for example, when the laser machining according to the first embodiment and the second embodiment is performed, a better machining result (for example, the above evaluation "A") is obtained in the region near 45 ° on the line A. There is room for improvement so that it can be obtained. In particular, the point where the line A defining the machining progress direction ND and the second crystal orientation K2 are orthogonal to each other is 0 °, the point where the line A and the first crystal orientation K1 are orthogonal to each other is 90 °, and 0 ° in the line A. When the intermediate point between 90 ° and 90 ° is set to 45 °, the direction of NH in the longitudinal direction of the beam shape and the inclination direction of the diagonal crack are opposite to each other with respect to the machining progress direction ND when machining the point at 45 °. When it is on the side, the quality of the trimmed surface tends to deteriorate.

On the other hand, as described above, the region including 45 ° in the line A is set separately from the first region A1 and the second region A2, and in the region, the direction of the longitudinal direction NH of the beam shape is the machining progress direction. If it is along the ND, the quality of the trimmed surface will be better. In this embodiment, laser processing is performed based on the above findings. Subsequently, the laser processing according to the fourth embodiment will be described.

Also in the fourth embodiment, as in the third embodiment, the object 11 is orthogonal to the (100) plane, one (110) plane, another (110) plane, and one (110) plane. The first crystal orientation K1 to be formed and the second crystal orientation K2 orthogonal to another (110) plane are included. Then, the point where the line A and the second crystal orientation K2 are orthogonal to each other is 0 °, the point where the line A and the first crystal orientation K1 are orthogonal to each other is 90 °, and 0 ° and 90 ° in the line A are defined. The point between them is 45 °.

Further, also in the fourth embodiment, the line A is a region between the first region A1 including 0 °, the second region A2 including 90 °, and the first region A1 and the second region A2. Includes an arcuate third region A3 that includes 45 °.

For such an object 11, in the fourth embodiment, first, the first portion 15A (see FIG. 31) of the object 11 is processed. That is, in the fourth embodiment, the first processing is carried out in the same manner as in the second embodiment. More specifically, as shown in FIG. 55, first, while rotating the stage 2, the control unit 6 switches ON / OFF of the irradiation of the laser beam L along the first region A1 of the line A. Therefore, the condensing region C is relatively moved to form the modified region 12, and the modified region 12 in the regions other than the first region A1 (second region A2 and third region A3) of the line A is formed. Stop forming (first processing).

In the first machining, the rotation direction of the stage 2 is controlled under the control of the moving section 4 of the control section 6, so that the machining progress direction ND is set to the forward direction ND1. Further, since the first processing is the processing of the first region A1, the laser beam L is formed by the spatial light modulator 7 under the control of the control unit 6, so that the beam shape of the condensing region C is formed. Is the first shape Q1. Further, here, the direction CD in which the diagonal crack extends is defined as the positive direction CD1 so as to incline in the direction outward from the center of the object 11 with respect to the Z direction toward the second surface 11b (see FIG. 31). To. The method of forming an oblique crack is the same as that of the first embodiment.

Subsequently, in the fourth embodiment, by switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 55, the second region A2 of the line A The condensing region C is relatively moved along the line A to form the modified region 12, and the modified region 12 in regions other than the second region A2 of the line A (first region A1 and third region A3). Stops the formation of (second processing).

In the second machining, the rotation direction of the stage 2 is controlled under the control of the moving section 4 of the control section 6, so that the machining progress direction ND is maintained in the same forward direction ND1 as the first machining. That is, between the first machining and the second machining, the forward / reverse of the machining progress direction ND (whether the forward direction ND1 or the reverse direction ND2 is used) is the same. Further, since the second processing is the processing of the second region A2, the laser beam L is formed by the spatial light modulator 7 under the control of the control unit 6, so that the beam shape of the condensing region C is formed. Is the second shape Q2. Further, here, the direction CD in which the diagonal crack extends is defined as the positive direction CD1 so as to incline in the direction outward from the center of the object 11 with respect to the Z direction toward the second surface 11b (see FIG. 31). To. The method of forming an oblique crack is the same as that of the first embodiment. When the order of the machining progress direction ND is the same for the first machining and the second machining, the reverse direction ND2 may be used, not limited to the forward direction ND1 as described above.

Subsequently, in the fourth embodiment, by switching ON / OFF of the irradiation of the laser beam L by the control unit 6 while rotating the stage 2, as shown in FIG. 55, the third region A3 of the line A The condensing region C is relatively moved along the line A to form the modified region 12, and the modified region 12 in regions other than the third region A3 of the line A (first region A1 and second region A2). Stops the formation of (third processing).

In the third processing of the third region A3, the beam shape of the condensing region C is set so that the longitudinal direction NH thereof follows the processing progress direction ND. Therefore, regardless of whether the machining progress direction ND is the forward direction ND1 or the reverse direction ND2, similarly good machining results (evaluation “A”) can be obtained (see FIG. 53).

Therefore, in the third machining, the order of the machining progress direction ND is not limited. However, the forward / reverse of the machining progress direction ND in the third machining is the same as the forward / reverse of the machining progress direction ND of the first machining and the second machining from the viewpoint of shortening the time related to the acceleration / deceleration related to the relative movement of the condensing region C. can do.

Subsequently, in the fourth embodiment, the second portion 15B (see FIG. 31) of the object 11 is processed. The processing of the second portion 15B can be performed in the same manner as in the first embodiment and the second embodiment. That is, when processing the second portion 15B, the above-mentioned separate processing (for example, first Z processing and second Z processing) can be performed.

Cracks

13a and 13b inclined toward the outer edge 110e of the joint region are formed.

The laser processing according to the above-mentioned fourth embodiment will be described as a configuration of the laser processing apparatus 1. That is, the laser processing apparatus 1 is for irradiating the object 11 with the laser light L (laser light L1, L2) to form the modified region 12, and at least a stage for supporting the object 11. 2, the irradiation unit 3 for irradiating the laser beam L toward the object 11 supported by the stage 2, and the condensing region C (condensing regions C1 and C2) of the laser beam L with respect to the object 11. It is provided with moving

units

4 and 5 for relative movement, and a control unit 6 for controlling the moving

units

4 and 5. As a result, the modified region 12 (modified

regions

cracks

units

4 and 5. As a result, the modified region 12 (modified

regions

On the other hand, the control unit 6 relatively moves the condensing region C (condensing region C1 and C2) along the third region A3 of the line A by controlling the irradiation unit 3 and the moving

units

4 and 5. As a result, the modified region 12 (modified

regions

12a, 12b) is formed in the object 11 along the third region A3, and the oblique crack 13F (crack 13a) extending from the modified region 12 toward the second surface 11b is formed. , 13b) The third processing process (the above-mentioned third processing) for forming) is executed. In particular, in the third processing, the control unit 6 controls the spatial light modulator 7 to form the laser beam L so that the longitudinal direction NH of the condensing region C is along the processing progress direction ND.

Subsequently, the laser processing according to the above-mentioned fourth embodiment will be described as a process of the laser processing method. That is, the laser processing method according to 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 is set on the object 11. By relatively moving the condensing region C (condensing region C1 and C2) along the first region A1 of the line A, the modified region 12 (modifying region 12) is moved to the object 11 along the first region A1. 12a, 12b) is formed, and an oblique crack 13F (diagonal crack 13F) extending diagonally from the modified region 12 toward the second surface 11b opposite to the first surface 11a, which is the incident surface of the object 11, in the Z direction. It has a first processing step (the above-mentioned first processing) for forming

cracks

13a, 13b).

regions

12a, 12b) on the object 11 and forming an oblique crack 13F (

cracks

On the other hand, in the laser processing method according to the present embodiment, the condensing region C (condensing region C1 and C2) is relatively moved along the third region A3 of the line A, so that the condensing region C (C1 and C2) is relatively moved along the third region A3. A third processing step of forming a modified region 12 (modified

regions

12a, 12b) on the object 11 and forming an oblique crack 13F (

cracks

13a, 13b) extending from the modified region 12 toward the second surface 11b. Has (the above third processing).

Then, in the third processing step, by controlling the spatial light modulator 7, the laser beam L is formed so that the longitudinal direction NH of the condensing region C is along the processing progress direction ND.

As described above, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the first processing and the second processing are performed in the same manner as in the second embodiment, so that the same effect as in the second embodiment can be obtained. Is possible. Further, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, a third region A3 including a point of 45 ° is interposed between the first region A1 and the second region A2. Then, in the third processing in which the processing of the third region A3 is performed, the longitudinal direction NH of the condensing region C of the laser beam L is set to be along the processing progress direction ND. Therefore, as shown in the above findings, the quality of the trimmed surface in the region including the 45 ° point is better. As described above, according to the laser processing apparatus 1 and the laser processing method according to the present embodiment, it is possible to form an oblique crack while suppressing the deterioration of the quality of the trim surface of the object 11.

Further, in the laser machining apparatus 1 and the laser machining method according to the present embodiment, the order of the machining progress direction ND is the same for at least the first machining and the second machining. Therefore, as compared with the case where the order of the processing progress direction ND is switched between the first processing and the second processing, the time related to the acceleration / deceleration of the relative movement of the condensing region C of the laser beam L is reduced.

units

4 and 5, so that the order of the processing progress direction ND of the condensing region C is first. It may be the same as the order of the machining progress direction ND of the machining process and the second machining process. In this case, in the first processing process, the second processing process, and the third processing process, the order of the processing progress direction ND is the same. As a result, it is possible to shorten the time required for acceleration and deceleration for relative movement of the condensing region C and suppress tact reduction.

In addition, with respect to the laser processing apparatus 1 and the laser processing method according to the fourth embodiment, the configurations of the above-mentioned first embodiment, the second embodiment, and the third embodiment, and the first embodiment and the first embodiment are also used. 2 Each configuration of the embodiment and the modification according to the third embodiment can be arbitrarily selected and adopted.

In the third embodiment and the fourth embodiment, the order of the first processing, the second processing, and the third processing is arbitrary.

Provided are a laser processing device capable of setting a processing progress direction more appropriately according to the crystal structure of an object, and a laser processing method.

1 ... Laser processing device, 2 ... Stage (support part), 3 ... Irradiation part, 4, 5 ... Moving part, 6 ... Control part, 7 ... Spatial light modulator, 11 ... Object, 11a ... First surface (incident) Surface), 11b ... Second surface (opposite surface), 12, 12a, 12b ... Modified region, 13, 13a, 13b ... Crack, 13F ... Diagonal crack, 33 ... Condensing lens, A1 ... First region, A2 ... 2nd region, A3 ... 3rd region, K1 ... 1st crystal orientation, K2 ... 2nd crystal orientation, L ... laser light, C, C1, C2 ... condensing region, ND ... processing progress direction.

Claims

A laser processing device for irradiating an object having a crystal structure with laser light to form a modified region.
A support portion for supporting the object and
An irradiation unit for irradiating the laser beam toward the object supported by the support unit, and an irradiation unit.
A moving portion for moving the focused region of the laser beam relative to the object, and a moving portion.
A control unit for controlling the moving unit and the irradiation unit,
Equipped with
An annular line including an arc-shaped first region and an arc-shaped second region is set on the object when viewed from the Z direction intersecting the incident surface of the laser beam.
The irradiation unit has a molding unit for molding the laser beam.
The control unit
By controlling the irradiation unit and the moving unit, the light collecting region is relatively moved along the first region of the line, thereby modifying the object along the first region. The first processing process of forming a region and forming an oblique crack extending diagonally with respect to the Z direction from the modified region toward the opposite surface of the object to the incident surface.
By controlling the irradiation unit and the moving unit, the light collecting region is relatively moved along the second region of the line, thereby modifying the object into the object along the second region. A second processing process for forming a region and forming the diagonal crack extending from the modified region toward the opposite surface.
And run
In the first processing process and the second processing process, the control unit switches the order of the processing progress direction, which is the moving direction of the light collecting region, between the first processing process and the second processing process.
Laser processing equipment.
The object includes a first portion and a second portion arranged in order from the opposite side along the Z direction.
The control unit executes the first machining process and the second machining process while switching the order of the machining progress direction with respect to the first portion, and the first machining process with respect to the second portion. Execution of processing and another processing processing different from the second processing processing,
In the separate processing, the control unit controls the irradiation unit and the moving unit to make the condensing region relative to the light collecting region along the line while making the order of the processing progress direction the same throughout the line. By moving the object, a crack extending from the modified region and the modified region along the Z direction is formed along the line.
The laser processing apparatus according to claim 1.
In the separate processing, the control unit controls the molding unit so that the light-collecting region has a longitudinal direction when viewed from the Z direction, and the longitudinal direction of the light-collecting region is the longitudinal direction. The laser beam is molded so as to follow the processing progress direction.
The laser processing apparatus according to claim 2.
The object includes a joining region joined to another member.
In the first processing and the second processing, the control unit is inclined from the inner position of the joint region toward the outer edge of the joint region as it goes from the incident surface to the opposite surface. Form,
The laser processing apparatus according to any one of claims 1 to 3.
The object has a (100) plane, one (110) plane, another (110) plane, a first crystal orientation orthogonal to the one (110) plane, and the other (110) plane. It has a crystal structure including a second crystal orientation orthogonal to the above, and is supported by the support portion so that the (100) plane becomes the incident plane.
In the first processing and the second processing, the control unit is
By controlling the molded portion, the condensing region has a longitudinal direction when viewed from the Z direction, and the longitudinal direction is the first crystal orientation and the second crystal orientation. The laser beam is formed so as to be inclined with respect to the processing progress direction in a direction approaching one side having a large angle with the processing progress direction which is the movement direction of the light collecting region.
The laser processing apparatus according to any one of claims 1 to 4.
In the first region, the point where the second crystal orientation and the line are orthogonal is 0 °, the point where the first crystal orientation and the line are orthogonal is 90 °, and the 0 ° and the line in the line are the same. Assuming that the point between 90 ° and 45 ° is 45 °, the region from 0 ° to 45 ° is included.
The second region includes the region from 45 ° to 90 °.
The laser processing apparatus according to claim 5.
In the first processing and the second processing, the control unit controls the moving unit so that when viewed from the Z direction, the direction of inclination in the longitudinal direction is relative to the processing progress direction. The order of the processing progress direction is switched between the first processing process and the second processing process so that the diagonal crack is on the same side as the extending direction.
The laser processing apparatus according to claim 5 or 6.
The object has a (100) plane, one (110) plane, another (110) plane, a first crystal orientation orthogonal to the one (110) plane, and the other (110) plane. It has a crystal structure including a second crystal orientation orthogonal to the above, and is supported by the support portion so that the (100) plane becomes the incident plane.
In the separate machining process, the control unit moves the condensing region relative to the first region of the line without switching the machining progress direction to the first region. The first Z processing process for forming the modified region in the object along the line and forming cracks extending from the modified region along the Z direction, and the second region of the line. A second Z processing process for forming the modified region on the object along the second region and forming cracks extending from the modified region along the Z direction by relatively moving the light collecting region. And execute,
In the 1st Z processing and the 2nd Z processing, the control unit controls the molding unit so that the light collecting region has a longitudinal direction when viewed from the Z direction and the longitudinal direction thereof. The laser beam is molded so that the direction is inclined with respect to the processing progress direction in a direction approaching one of the first crystal orientation and the second crystal orientation, which has a larger angle with the processing progress direction. ,
The laser processing apparatus according to claim 2 or 3.
In the line, the point where the second crystal orientation and the line are orthogonal to each other is 0 °, the point where the first crystal orientation and the line are orthogonal to each other is 90 °, and the 0 ° and the 90 ° in the line are defined. When the point between the two is 45 °, it is the region between the first region including the 0 °, the second region including the 90 °, and the first region and the second region. Including the arcuate third region including the 45 °
The control unit controls the irradiation unit and the moving unit to move the light collecting region relative to the third region of the line, thereby moving the light collecting region relative to the target along the third region. A third processing process for forming the modified region on the object and forming the diagonal crack extending from the modified region toward the opposite surface was executed.
In the third processing, the control unit controls the molding unit so that the light collecting region has a longitudinal direction when viewed from the Z direction, and the longitudinal direction is the processing progress direction. The laser beam is molded so as to be in line with.
The laser processing apparatus according to claim 5 or 8.
In the third processing process, the control unit controls the moving unit to reverse the order of the processing progress direction of the light collecting region to the first of the first processing process and the second processing process. 3 Same as the reverse order of the machining progress direction while being executed continuously with the machining process.
The laser processing apparatus according to claim 9.
In the first processing and the second processing, the control unit controls the moving unit so that when viewed from the Z direction, the direction of inclination in the longitudinal direction is relative to the processing progress direction. The order of the processing progress direction is switched between the first processing process and the second processing process so that the diagonal crack is on the same side as the extending direction.
The laser processing apparatus according to claim 9 or 10.
In the first processing and the second processing, the control unit is
The first modified region and the first modified region as the modified region are obtained by relatively moving the focused region along the line while setting the position of the focused region in the Z direction to the first Z position. 1 The first forming process for forming a crack extending from the modified region on the object, and
The modification is performed by relatively moving the condensing region along the line while setting the position of the condensing region in the Z direction to the second Z position on the incident surface side of the first Z position. A second reforming region as a region and a second forming treatment for forming cracks extending from the second reforming region are performed.
In the first forming process, the control unit sets the position of the light collecting region in the Y direction intersecting the processing progress direction and the Z direction at the first Y position.
In the second forming process, the control unit sets the position of the light collecting region in the Y direction to the second Y position shifted from the first Y position, and is controlled by the molding unit in the Y direction and. The laser beam is formed so that the shape of the condensing region in the YZ plane including the Z direction is inclined in the direction of the shift at least on the incident surface side of the center of the condensing region. By doing so, the oblique crack is formed in the YZ plane so as to be inclined in the direction of the shift.
The laser processing apparatus according to any one of claims 1 to 11.
The molding unit includes a spatial light modulator for molding the laser beam by modulating the laser beam according to a modulation pattern.
The irradiation unit includes a condenser lens for condensing the laser beam from the spatial light modulator toward the object.
In the second forming process, the control unit modulates the laser beam so that the shape of the condensing region becomes the inclined shape by controlling the modulation pattern displayed on the spatial light modulator. Molding laser light,
The laser processing apparatus according to claim 12.
The modulation pattern includes a coma aberration pattern for imparting coma aberration to the laser beam.
In the second forming process, the control unit controls the magnitude of the coma aberration according to the coma aberration pattern to perform the first pattern control for making the shape of the condensing region into the inclined shape.
The laser processing apparatus according to claim 13.
The modulation pattern includes a spherical aberration correction pattern for correcting the spherical aberration of the laser beam.
In the second forming process, the control unit offsets the center of the spherical aberration correction pattern in the Y direction with respect to the center of the entrance pupil surface of the focusing lens, thereby changing the shape of the focusing region. Perform the second pattern control to make the shape inclined,
The laser processing apparatus according to claim 13 or 14.
In the second forming process, the control unit causes the spatial light modulator to display the modulation pattern asymmetrical with respect to the axis along the processing progress direction, thereby changing the shape of the light collecting region into the inclined shape. 3rd pattern control for
The laser processing apparatus according to any one of claims 13 to 15.
The modulation pattern is an ellipse for making the shape of the condensing region in the XY plane including the X direction intersecting the Y direction and the Z direction and the Y direction into an elliptical shape having the X direction as a length. Including patterns,
In the second forming process, the control unit causes the spatial light modulator to display the modulation pattern so that the intensity of the ellipse pattern is asymmetric with respect to the axis along the X direction. A fourth pattern control is performed to make the shape of the light collecting region the inclined shape.
The laser processing apparatus according to any one of claims 13 to 16.
In the second formation process, the control unit uses the spatial light modulator to form the modulation pattern for forming a plurality of focusing points of the laser light arranged along the shift direction in the YZ plane. The fifth pattern control for changing the shape of the light collecting region including the plurality of light collecting points into the inclined shape is performed.
The laser processing apparatus according to any one of claims 13 to 17.
It is a laser processing method for irradiating an object having a crystal structure with laser light to form a modified region.
By relatively moving the condensing region of the laser beam along the first region of the lines set on the object, the modified region is formed on the object along the first region. The first processing step of forming an oblique crack extending diagonally from the modified region toward the opposite surface of the object to the incident surface of the laser beam in the Z direction intersecting the incident surface.
By relatively moving the condensing region along the second region of the line, the modified region is formed on the object along the second region, and the modified region is opposed to the opposite surface. The second processing step of forming the diagonal crack extending toward
Equipped with
The object is set with the annular line including the arc-shaped first region and the arc-shaped second region when viewed from the Z direction.
In the first processing step and the second processing step, the order of the processing progress, which is the moving direction of the light collecting region, is switched between the first processing step and the second processing step.
Laser processing method.