CN116075389A - Laser processing device and laser processing method - Google Patents

Laser processing device and laser processing method Download PDF

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Publication number
CN116075389A
CN116075389A CN202180061227.5A CN202180061227A CN116075389A CN 116075389 A CN116075389 A CN 116075389A CN 202180061227 A CN202180061227 A CN 202180061227A CN 116075389 A CN116075389 A CN 116075389A
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region
light
processing
laser
forming
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坂本刚志
佐野育
杉浦银治
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Hamamatsu Photonics KK
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/073—Shaping the laser spot
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/50—Working by transmitting the laser beam through or within the workpiece
    • B23K26/53—Working by transmitting the laser beam through or within the workpiece for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting

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  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Plasma & Fusion (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
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  • Oil, Petroleum & Natural Gas (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • Chemical & Material Sciences (AREA)
  • Laser Beam Processing (AREA)

Abstract

The disclosed laser processing device for forming a modified region by irradiating an object having a crystal structure with laser light, is provided with: a support section for supporting the object; an irradiation unit configured to irradiate the laser beam toward the object supported by the support unit; a moving unit for moving a condensed region of the laser light relative to the object; and a control unit configured to control the moving unit and the irradiation unit, wherein a circular line including a circular 1 st region and a circular 2 nd region is set in the object as viewed from a Z direction intersecting with an incident surface of the laser beam, and the irradiation unit includes a forming unit configured to form the laser beam.

Description

Laser processing device and laser processing method
Technical Field
An aspect of the present disclosure relates to a laser processing apparatus and a laser processing method.
Background
Patent document 1 describes a laser processing apparatus including: a holding mechanism for holding the workpiece, and a laser irradiation mechanism for irradiating the workpiece held by the holding mechanism with laser. The laser processing apparatus described in patent document 1 fixes a laser irradiation mechanism having a condenser lens to a base, and moves a workpiece in a direction perpendicular to an optical axis of the condenser lens by a holding mechanism.
Prior art literature
Patent literature
Patent document 1: japanese patent No. 5456510
Patent document 2: japanese patent laid-open No. 2020-069530
Disclosure of Invention
Problems to be solved by the invention
However, in a manufacturing process of a semiconductor device, for example, a trimming process for removing an outer peripheral portion of a semiconductor wafer as an unnecessary portion may be performed. That is, in order to remove the outer edge portion from the object, there is a case where a converging point of the laser light is relatively moved along a line extending in a ring shape inside the outer edge of the object, thereby forming a modified region along the line.
On the other hand, according to the findings of the present inventors, in the case of extending the crack from the modified region to the surface opposite thereto from the incident surface side of the laser beam of the object during the trimming processing, it is required to extend the crack obliquely to the thickness direction instead of extending the crack in the vertical direction along the thickness direction of the object. This is because, for example, when the crack is stretched in the thickness direction, it is suppressed from reaching another member (for example, a wafer bonded to the object) arranged directly under the object in the thickness direction. In this case, according to the findings of the present inventors, there is room for improvement in setting the direction of the relative movement of the converging point, that is, the machining traveling direction, in accordance with the crystal structure of the object.
In this regard, an object of the present disclosure is to provide a laser processing apparatus and a laser processing method capable of appropriately setting a processing traveling direction according to a crystal structure of an object.
Technical means for solving the problems
The present inventors have conducted intensive studies to solve the above problems, and have obtained the following findings. That is, when cracks are formed obliquely to the thickness direction, in the case where the object has a crystal structure, the appropriate processing direction may be different between a certain region and other regions. Thus, the machine direction is not set to the same direction in all the areas, but the machine direction is switched to the reverse direction, so that the machine direction can be set more appropriately. An aspect of the present disclosure is accomplished based on such an insight. The switching of the machining traveling direction is to switch the machining traveling direction to a counterclockwise direction (for example, a clockwise direction) or to a clockwise direction (for example, a reverse direction) when machining is performed along a circular line, for example.
That is, the laser processing apparatus according to one aspect of the present disclosure is a laser processing apparatus for forming a modified region by irradiating an object having a crystal structure with laser light, and includes: a support section for supporting an object; an irradiation unit for irradiating a laser beam toward the object supported by the support unit; a moving unit for relatively moving a laser light converging region with respect to an object; and a control unit for controlling the moving unit and the irradiation unit, wherein, when viewed from a Z direction intersecting with an incident surface of the laser beam, an annular line including an arc-shaped 1 st region and an arc-shaped 2 nd region is set in the object, the irradiation unit includes a forming unit for forming the laser beam, and the control unit performs: a 1 st processing step of forming a modified region in the object along the 1 st region by controlling the irradiation section and the moving section so that the condensed region is relatively moved along the 1 st region in the line, and forming an oblique crack extending obliquely with respect to the Z direction from the modified region toward an opposite surface opposite to the incident surface of the object; and a 2 nd processing step of forming a modified region in the object along the 2 nd region by controlling the irradiation unit and the moving unit so that the condensed region is relatively moved along the 2 nd region in the line, and forming an oblique crack extending from the modified region toward the opposite surface, wherein in the 1 st processing step and the 2 nd processing step, the control unit switches the forward and backward directions of the movement direction of the condensed region, that is, the processing direction of the condensed region, between the 1 st processing step and the 2 nd processing step.
Alternatively, a laser processing method according to an aspect of the present disclosure is a laser processing method for forming a modified region by irradiating an object having a crystal structure with laser light, and includes: a 1 st processing step of forming a modified region in the object along a 1 st region by relatively moving a laser light condensing region along the 1 st region in a line set in the object, and forming an oblique crack extending obliquely with respect to a Z direction intersecting the incident surface from the modified region toward an opposite surface opposite to the incident surface of the laser light of the object; and a 2 nd processing step of forming a modified region in the object along the 2 nd region by relatively moving the light-collecting region along the 2 nd region in the line, and forming an oblique crack extending from the modified region toward the opposite surface, wherein the object is provided with the line in a circular shape including the 1 st region in a circular arc shape and the 2 nd region in a circular arc shape when viewed from the Z direction, and the 1 st processing step and the 2 nd processing step are performed by switching the forward and backward directions of the movement direction of the light-collecting region, that is, the processing direction, between the 1 st processing step and the 2 nd processing step.
In these apparatuses and methods, the object has a crystal structure. Here, in the case where the 1 st region of the line along which the laser light condensing region is relatively moved forms the modified region in the object (1 st processing, 1 st processing step), and in the case where the 2 nd region of the line forms the modified region in the object (2 nd processing, 2 nd processing step), an oblique crack extending obliquely with respect to the Z direction (direction intersecting the incident surface) from the modified region toward the opposite surface opposite to the incident surface of the object is formed. Then, as shown in the above-described findings, the forward and backward directions of the machining traveling direction are switched between the 1 st machining process (1 st zone) and the 2 nd machining process (2 nd zone), and the machining traveling direction can be set more appropriately according to the crystal structure of the object.
In the laser processing apparatus according to one aspect of the present disclosure, the object may include: the control unit executes the 1 st processing and the 2 nd processing on the 1 st portion while switching the forward and backward directions of the processing traveling direction, and executes another processing different from the 1 st processing and the 2 nd processing on the 2 nd portion, and the control unit controls the irradiation unit and the moving unit in the other processing, so that the forward and backward directions of the processing traveling direction are the same throughout the entire line and the light collecting region is relatively moved along the line, thereby forming a modified region in the object along the line and a crack extending from the modified region in the Z direction. In this case, laser processing is performed in which the direction of the processing traveling direction is the same throughout the entire line in the portion 2 where the crack is formed along the Z direction. Thus, compared to the case where the 2 nd portion is also in the 1 st and 2 nd regions of the line to switch the forward and backward directions of the machining traveling direction, the time required for acceleration and deceleration of the relative movement of the laser light condensing region can be reduced.
In the laser processing apparatus according to one aspect of the present disclosure, the control unit may control the forming unit to form the laser beam by: the light-collecting region is provided with a long-side direction when viewed from the Z direction, and the long-side direction of the light-collecting region is along the machine direction. In this case, in the 2 nd portion where the crack is formed along the Z direction, it is not necessary to change the relation between the longitudinal direction of the light collecting region and the machining traveling direction between the machining of the 1 st region and the machining of the 2 nd region of the laser beam forming line, and therefore, the processing of the control unit is simplified.
In the laser processing apparatus according to one aspect of the present disclosure, the object may include: in the joint region to be joined to another member, the control unit forms an oblique crack inclined from a position inside the joint region toward an outer edge of the joint region as going from the incident surface toward the opposite surface in the 1 st processing and the 2 nd processing. In this case, when a part of the object bounded by the oblique crack is removed from the object and a residual part of the object is left, the object can be prevented from extending outward across the joint region with the other member.
Here, the present inventors have further studied based on the above findings, and have obtained the following findings. That is, in order to remove the outer edge portion from the object, when the converging point of the laser beam is relatively moved along a line extending in a loop shape inside the outer edge of the object, and the modification region is formed along the line (trimming processing is performed), there is a concern that the quality of the trimming surface of the object formed by removing the outer edge portion may be lowered by the location. That is, according to the findings of the present inventors, it is required to form oblique cracks while suppressing the quality degradation of the trimming surface of the object with the outer edge portion removed.
The inventors of the present invention have found that the following further findings are obtained with respect to suppression of quality degradation of the trimming surface. That is, in the case of a wafer having a (100) plane as a main surface and a 1 st crystal orientation orthogonal to one (110) plane and a 2 nd crystal orientation orthogonal to the other (110) plane, the object is formed in such a manner that the angle between the 1 st crystal orientation and the 2 nd crystal orientation and the machining traveling direction (the direction of relative movement of the converging point) is larger, and the beam shape inclined with respect to the machining traveling direction is formed, whereby the reduction in quality of the outer surface can be suppressed (for example, refer to patent document 2).
More specifically, for example, when the crack extending from the modified region is pulled by the 1 st crystal orientation, the beam is shaped into a long shape, and the longitudinal direction is inclined to the machine direction so as to approach the 2 nd crystal orientation on the opposite side to the 1 st crystal orientation side, instead of the machine direction. Thus, it is considered that the beam shape is elongated with respect to the crack extension force due to the crystal orientation (crystal axis) to exert the function of canceling the crack extension force, and the crack can be extended in the machine direction with high accuracy.
In addition, when the crack extending from the modified region is pulled by, for example, the 2 nd crystal orientation, the beam is shaped into a long shape, and the longitudinal direction is inclined to approach the 1 st crystal orientation on the opposite side to the 2 nd crystal orientation side with respect to the machine direction without being oriented in the machine direction. Thus, it is considered that the beam shape is elongated to exert the effect of canceling the crack extension force due to the crystal orientation, and the crack can be extended in the machine direction with high accuracy. As a result, it is considered that the quality of the finishing surface is suppressed from being lowered. The present inventors completed the following invention based on this knowledge.
That is, in the laser processing apparatus according to the aspect of the present disclosure, the object may have a crystal structure including: (100) A surface, one (110) surface, the other (110) surface, a 1 st crystal orientation orthogonal to the one (110) surface, and a 2 nd crystal orientation orthogonal to the other (110) surface, and is supported by the support portion so that the (100) surface becomes an incident surface, and in the 1 st processing and the 2 nd processing, the control portion controls the forming portion to form the laser beam: the light-collecting region has a longitudinal direction when viewed from the Z direction, and the longitudinal direction of the light-collecting region is inclined with respect to the machine direction in a direction approaching the larger angle between the 1 st crystal orientation and the 2 nd crystal orientation and the machine direction, which is the direction of movement of the light-collecting region. In this case, as shown in the above-mentioned findings, the quality of the trimming surface is reduced.
On the other hand, the present inventors have further studied based on the above findings, and have found that even when the direction of the longitudinal direction of the beam shape is set as described above based on the processing traveling direction and the crystal structure, there is room for further suppressing the quality degradation of the trimming surface due to the relationship between the direction of the longitudinal direction of the beam shape and the oblique direction of the oblique crack. That is, the quality of the trimming surface is relatively good when the direction of the long side of the beam shape is on the same side as the oblique direction of the oblique crack, and is relatively poor when the direction of the long side of the beam shape is on the opposite side from the oblique direction of the oblique crack.
In order to solve this problem, the direction of the longitudinal direction of the beam shape with respect to the machining traveling direction is determined in accordance with the crystal structure of the object (that is, in accordance with the magnitude relation of the angle between the machining traveling direction and the 1 st and 2 nd crystal orientations as described above), and thus the degree of freedom of change is small. In order to combine the long-side direction of the beam shape with the oblique direction of the oblique crack to obtain a relatively good quality, it is effective to switch the machine direction in the forward and reverse directions in accordance with the crystal structure of the machined region. That is, by appropriately setting the machining traveling direction according to the crystal structure of the object as described above, the quality degradation of the trimming surface can be further suppressed. The following invention has been completed based on the above findings.
That is, in the laser processing apparatus according to the aspect of the present disclosure, the control unit may control the moving unit in the 1 st processing and the 2 nd processing so that the forward and backward directions of the processing travel direction can be switched between the 1 st processing and the 2 nd processing: the direction of inclination of the long side direction is the same as the direction in which the oblique crack extends in the machine direction when viewed from the Z direction. In this case, in both the 1 st and 2 nd regions, the direction of inclination with respect to the longitudinal direction of the light collecting region in the machine direction is the same as the side on which the oblique crack extends. Therefore, as shown in the above-mentioned findings, the relationship between the direction of the longitudinal direction of the light collecting region and the oblique direction of the oblique crack can be a combination that can obtain relatively good quality, and the quality degradation is suppressed. As described above, oblique cracks can be formed while suppressing degradation of the quality of the trimming surface of the object.
In the laser processing apparatus according to the aspect of the present disclosure, the control unit may execute the processing without switching the processing traveling direction in the other processing steps: a 1 st Z processing step of forming a modified region in the object along the 1 st region by relatively moving the light-collecting region along the 1 st region in the line, and forming a crack extending in the Z direction from the modified region; and a 2Z processing process of forming a modified region in the object along the 2 nd region by relatively moving the light-collecting region along the 2 nd region in the line and forming a crack extending in the Z direction from the modified region, wherein the control unit controls the forming unit to form the laser beam into: the light-collecting region has a long-side direction when viewed from the Z direction, and the direction in which the long-side direction approaches the direction in which the angle between the 1 st crystal orientation and the 2 nd crystal orientation and the movement direction of the light-collecting region, that is, the machine direction is larger is inclined with respect to the machine direction. In this case, the 2 nd portion can reduce the time required for acceleration and deceleration of the relative movement of the laser beam converging region, as compared with the case where the longitudinal direction of the converging region is set in the 1 st region and the 2 nd region and the forward and reverse directions of the machine direction are switched in the 1 st region and the 2 nd region, depending on the machine direction.
On the other hand, the present inventors have further studied based on the above findings, and have found that even when the direction of the longitudinal direction of the beam shape is set as described above based on the processing traveling direction and the crystal structure, there is room for further suppressing the quality degradation of the trimming surface in a specific region of the crystal structure. That is, in the case where the object has a crystal structure having a (100) plane, one (110) plane, the other (110) plane, a 1 st crystal orientation orthogonal to the one (110) plane, and a 2 nd crystal orientation orthogonal to the other (110) plane, the quality of the trimming surface is improved when the longitudinal direction of the beam shape is oriented along the machine direction in the region around 45 ° when the point where the line for relatively moving the laser light converging region is orthogonal to the 2 nd crystal orientation is 0 °, the point where the line is orthogonal to the 1 st crystal orientation is 90 °, and the point between 0 ° and 90 ° of the line is 45 °. The following invention has been completed based on the above findings.
That is, in the laser processing apparatus according to the aspect of the present disclosure, when the line has a point where the 2 nd crystal orientation is perpendicular to the line of 0 °, a point where the 1 st crystal orientation is perpendicular to the line of 90 °, and a point between 0 ° and 90 ° of the line of 45 °, the apparatus may include: the control unit performs a 3 rd processing treatment of controlling the irradiation unit and the moving unit to relatively move the light collecting region along the 3 rd region in the line, thereby forming a modified region in the object along the 3 rd region, and forming an oblique crack extending from the modified region toward the opposite surface, in the 3 rd processing treatment, the control unit controls the forming unit to form the laser beam into: the light-collecting region has a longitudinal direction when viewed from the Z direction, and the longitudinal direction of the light-collecting region is along the machine direction. In this case, in the 3 rd processing process of processing the 3 rd region including the 45 ° point, the longitudinal direction of the laser light converging region is made to be along the processing traveling direction. Therefore, as shown in the above-mentioned findings, the quality of the trimming surface of the region including the 45 ° point becomes better.
In the laser processing apparatus according to the aspect of the present disclosure, in the 3 rd processing, the control unit may control the moving unit so that the forward and backward directions of the processing traveling direction of the light collecting region are the same as the forward and backward directions of the processing traveling direction of one of the 1 st processing and the 2 nd processing, which are continuously performed with the 3 rd processing. In this case, the time required for acceleration and deceleration for relative movement of the light collecting region is shortened, and the efficiency reduction can be suppressed.
In the laser processing apparatus according to the aspect of the present disclosure, in the 1 st processing and the 2 nd processing, the control unit controls the moving unit so that the forward and backward directions of the processing travel direction can be switched between the 1 st processing and the 2 nd processing: the direction of inclination of the long side direction is the same as the direction in which the oblique crack extends with respect to the machine direction when viewed from the Z direction. In this case, in both the 1 st and 2 nd regions, the direction of inclination with respect to the longitudinal direction of the light collecting region in the machine direction is the same as the side on which the oblique crack extends. Therefore, as shown in the above-mentioned findings, the relationship between the direction of the longitudinal direction of the light collecting region and the oblique direction of the oblique crack can be a combination that can obtain relatively good quality, and the quality degradation is suppressed. As described above, oblique cracks can be formed while suppressing degradation of the quality of the trimming surface of the object.
In the laser processing apparatus according to the aspect of the present disclosure, the control unit may execute: a 1 st formation process of forming a 1 st modified region as a modified region and a crack extending from the 1 st modified region on an object by setting the position of the light-collecting region in the Z direction as a 1 st Z position and relatively moving the light-collecting region along a line; and a 2 nd forming process of forming a 2 nd modified region as a modified region and a crack extending from the 2 nd modified region by setting a position of the light-collecting region in the Z direction to a 2 nd Z position on the incident surface side than the 1 st Z position and relatively moving the light-collecting region along a line, wherein in the 1 st forming process, the control unit sets a position of the light-collecting region in the Y direction intersecting the machining traveling direction and the Z direction to a 1 st Y position, and in the 2 nd forming process, the control unit sets a position of the light-collecting region in the Y direction to a 2 nd Y position shifted from the 1 st Y position and forms laser light by control of the forming unit: the shape of the light-collecting region in the YZ plane including the Y direction and the Z direction is formed in an inclined shape inclined in the shift direction at least in the incidence plane side with respect to the center of the light-collecting region, so that an oblique crack is formed in the YZ plane obliquely in the shift direction. Thus, oblique cracks inclined with respect to the Z direction can be formed appropriately.
In the laser processing apparatus according to one aspect of the present disclosure, the forming section may include: a spatial light modulator for shaping laser light by modulating the laser light according to a modulation pattern, the irradiation section including: in the 2 nd forming process, the control unit modulates the laser beam to form a light-condensing region in an inclined shape by controlling the modulation pattern displayed on the spatial light modulator, thereby forming the laser beam. In this case, the laser light can be easily shaped using a spatial light modulator.
In the laser processing apparatus according to one aspect of the present disclosure, the modulation pattern may include: the 1 st pattern control for forming the shape of the light-collecting region into an oblique shape is performed by controlling the magnitude of coma aberration of the coma aberration pattern in the 2 nd formation process and the control unit. According to the findings of the present inventors, in this case, the shape of the light-collecting region in the YZ plane is formed in an arc shape. That is, in this case, the shape of the light collecting region is inclined in the direction of the displacement in the side direction of the incident surface than the center of the light collecting region, and is inclined in the direction opposite to the displacement direction in the side direction opposite to the incident surface than the center of the light collecting region. Even in this case, oblique cracks inclined in the displacement direction may be formed.
In the laser processing apparatus according to one aspect of the present disclosure, the modulation pattern may include: in the 2 nd formation process, the control unit shifts the center of the spherical aberration correction pattern in the Y direction with respect to the center of the entrance pupil plane of the condenser lens, thereby performing 2 nd pattern control for forming the shape of the condenser region into an oblique shape. According to the findings of the present inventors, in this case as well, as in the case of using the coma aberration pattern, the shape of the light converging region in the YZ plane can be formed in an arc shape, and oblique cracks inclined in the shift direction can be formed.
In the laser processing apparatus according to one aspect of the present disclosure, in the 2 nd formation process, the control unit may display a modulation pattern asymmetric with respect to an axis along the processing direction on the spatial light modulator, thereby performing the 3 rd pattern control for making the shape of the light collecting region an oblique shape. According to the findings of the present inventors, in this case, the entirety of the shape of the light-collecting region in the YZ plane can be inclined in the shift direction. In this case, an oblique crack inclined in the offset direction may be formed.
In the laser processing apparatus according to one aspect of the present disclosure, the modulation pattern may include: an elliptical pattern for forming the shape of the light-collecting region in the Y direction and the XY plane including the X direction and the Y direction intersecting the Z direction into an elliptical shape having the X direction as a long side, and in the 2 nd forming process, the control unit displays the modulation pattern on the spatial light modulator so that the intensity of the elliptical pattern becomes asymmetric with respect to the axis along the X direction, thereby performing a 4 th pattern control for forming the shape of the light-collecting region into an oblique shape. According to the findings of the present inventors, in this case, the shape of the light-collecting region in the YZ plane may be formed in an arc shape, and an oblique crack inclined in the displacement direction may be formed.
In the laser processing apparatus according to one aspect of the present disclosure, in the 2 nd formation process, the control unit may display a modulation pattern for forming the condensed spots of the plurality of lasers aligned in the shift direction in the YZ plane on the spatial light modulator, thereby performing 5 th pattern control for making the shape of the condensed area including the plurality of condensed spots an oblique shape. According to the findings of the present inventors, oblique cracks inclined in the displacement direction may be formed in this case.
In the laser processing apparatus according to the aspect of the present disclosure, when the point at which the 2 nd crystal orientation is perpendicular to the line is 0 °, the point at which the 1 st crystal orientation is perpendicular to the line is 90 °, and the point between 0 ° and 90 ° of the line is 45 °, the 1 st region may include a region ranging from 0 ° to 45 °, and the 2 nd region may include a region ranging from 45 ° to 90 °. Thus, when the object is a wafer having the (100) plane as the incident plane, the quality of the trimming surface of the object can be reliably prevented from being lowered by the location.
ADVANTAGEOUS EFFECTS OF INVENTION
According to one aspect of the present disclosure, a laser processing apparatus and a laser processing method can be provided that suppress degradation in quality of a trimming surface of an object with an outer edge portion removed, and form oblique cracks.
Drawings
Fig. 1 is a schematic view showing a configuration of a laser processing apparatus according to an embodiment.
Fig. 2 is a schematic view showing the structure of the laser irradiation section.
Fig. 3 is a diagram showing the 4f lens unit shown in fig. 2.
Fig. 4 is a diagram showing the spatial light modulator shown in fig. 2.
Fig. 5 is a cross-sectional view of an object for explaining the observation of formation of oblique cracks.
Fig. 6 is a cross-sectional view of an object for explaining the observation of formation of oblique cracks.
Fig. 7 is a diagram showing the beam shape of the laser light condensing region.
Fig. 8 is a diagram showing the offset (offset) of the modulation pattern.
FIG. 9 is a photograph showing a cross section of a state of formation of oblique cracks.
Fig. 10 is a schematic plan view of the object.
FIG. 11 is a photograph showing a cross section of a state of formation of oblique cracks.
FIG. 12 is a photograph showing a cross section of a state of formation of oblique cracks.
Fig. 13 is a diagram showing an example of a modulation pattern.
Fig. 14 is a diagram showing the intensity distribution of the entrance pupil plane of the condenser lens and the beam shape of the condenser region.
Fig. 15 is a diagram showing the observation results of the beam shape of the light-collecting region and the intensity distribution of the light-collecting 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 an intensity distribution of an entrance pupil plane of the condenser lens and a beam shape of a condenser region.
Fig. 19 is a diagram showing an example of a modulation pattern and formation of a light condensing region.
Fig. 20 is a diagram showing a processed object.
Fig. 21 is a diagram showing a processed object.
Fig. 22 is a schematic view showing the beam shape of the light condensing region.
Fig. 23 is a schematic view showing the beam shape of the light condensing region.
Fig. 24 is a diagram showing a step of the trimming process.
Fig. 25 is a diagram showing a step of the trimming process.
Fig. 26 is a diagram showing a step of the trimming process.
Fig. 27 is a diagram showing a step of the trimming process.
Fig. 28 is a diagram showing a step of the trimming process.
Fig. 29 is a diagram showing a step of the trimming process.
Fig. 30 is a diagram showing an object to be laser-processed according to an embodiment.
Fig. 31 is a cross-sectional view of the object shown in fig. 30.
Fig. 32 is a plan view of the object shown in fig. 30.
FIG. 33 is a photograph showing the result of processing.
Fig. 34 is a cross-sectional photograph showing the processing result.
Fig. 35 is a schematic view for explaining a processing test.
Fig. 36 is a schematic view showing a relationship between a processing traveling direction in a processing test and a beam shape and an oblique crack.
Fig. 37 is a table showing the results of the processing tests shown in fig. 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 a step of laser processing according to an embodiment.
Fig. 41 is a diagram showing a step of laser processing according to an embodiment.
Fig. 42 is a diagram showing a step of laser processing according to an embodiment.
Fig. 43 is a diagram showing a step of laser processing according to an embodiment.
Fig. 44 is a diagram showing a step of laser processing according to an embodiment.
Fig. 45 is a diagram showing a step of laser processing according to an embodiment.
Fig. 46 is a diagram showing a step of laser processing according to an embodiment.
Fig. 47 is a diagram showing a step of laser processing according to an embodiment.
Fig. 48 is a diagram showing an object to be laser-processed 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 view showing the beam shape when the 3 rd region is processed.
Fig. 53 is a table showing the processing results of the beam shape shown in fig. 52.
Fig. 54 is a diagram for explaining laser processing according to embodiment 3.
Fig. 55 is a diagram for explaining laser processing according to embodiment 4.
Detailed Description
An embodiment will be described in detail below with reference to the drawings. In each drawing, the same or corresponding portions are denoted by the same reference numerals, and overlapping description thereof may be omitted. In each of the drawings, a rectangular coordinate system defined by an X axis, a Y axis, and a Z axis may be shown.
[ outline of laser processing device and laser processing ]
Fig. 1 is a schematic view showing a configuration of a laser processing apparatus according to an embodiment. As shown in fig. 1, the laser processing apparatus 1 includes: a mounting table (support) 2, an irradiation unit 3, moving units 4, 5, and a control unit 6. The laser processing apparatus 1 is an apparatus for forming a modified region 12 in an object 11 by irradiating the object 11 with laser light L.
The stage 2 holds, for example, a film attached to the object 11, and supports the object 11. The mounting table 2 is rotatable about an axis parallel to the Z direction as a rotation axis. The mounting table 2 may be moved in the X direction and the Y direction, respectively. The X direction and the Y direction are the 1 st horizontal direction and the 2 nd horizontal direction intersecting (orthogonal to) each other, and the Z direction is the vertical direction.
The irradiation unit 3 irradiates the object 11 with the laser light L having transparency with respect to the object 11 by condensing the laser light L. If the laser light L is condensed in the object 11 supported by the stage 2, the laser light L is particularly absorbed in a portion corresponding to a condensed region C (for example, a center Ca described later) of the laser light L, and a modified region 12 is formed in the object 11. The condensed region C will be described in detail below as a region in a range defined by a position where the intensity of the laser beam L is highest or a position apart from the center of gravity of the intensity of the laser beam L.
The modified region 12 is a region having a density, refractive index, mechanical strength, and other physical properties different from those of the surrounding non-modified region. As the modified region 12, for example, there are: a melt-processed region, a crack region, an insulation failure region, a refractive index change region, and the like. The modified region 12 is formed such that a crack extends from the modified region 12 to the incident side of the laser light L and the opposite side thereof. Such modified region 12 and crack are used for cutting object 11, for example.
For example, if the stage 2 is moved in the X direction and the light collecting region C is moved relative to the object 11 in the X direction, the plurality of modification points 12s are formed so as to be aligned in a row along the X direction. A modified spot 12s is formed by irradiation of a pulsed laser light L. A row of modified regions 12 is a collection of a plurality of modified dots 12s arranged in a row. The adjacent modified spots 12s may be connected to each other or separated from each other depending on the relative movement speed of the condensed region C with respect to the object 11 and the repetition frequency of the laser beam L.
The moving unit 4 includes: a 1 st moving unit 41 that moves the mounting table 2 in one direction in a plane intersecting (orthogonal to) the Z direction; and a 2 nd moving unit 42 that moves the stage 2 in another direction in a plane intersecting (orthogonal to) the Z direction. As an example, the 1 st moving unit 41 moves the table 2 in the X direction, and the 2 nd moving unit 42 moves the table 2 in the Y direction. The moving unit 4 rotates the mounting table 2 about an axis parallel to the Z direction as a rotation axis. The moving section 5 supports the irradiation section 3. The moving unit 5 moves the irradiation unit 3 in the X direction, the Y direction, and the Z direction. In a state where the condensed region C of the laser light L is formed, the stage 2 and/or the irradiation unit 3 are moved, and the condensed region C is moved relative to the object 11. That is, the moving parts 4 and 5 are moving parts that move at least one of the stage 2 and the irradiation part 3 so as to move the condensed region C of the laser light 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 includes: a processing unit, a storage unit, and an input receiving unit (not shown). The processing unit is configured as a computer device including a processor, a memory, a storage unit, a communication device, and the like. In the processing section, the processor executes software (program) read into the memory or the like, and controls reading and writing of data from and into the memory and the storage section, 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 receives input of the various information from a user. The input receiving portion constitutes GUI (Graphical User Interface).
Fig. 2 is a schematic diagram showing the structure of the irradiation section shown in fig. 1. In fig. 2, it is shown that: a predetermined virtual line a for laser processing is shown. As shown in fig. 2, the irradiation section 3 includes: a light source 31, a spatial light modulator (forming section) 7, a condenser lens 33, and a 4f lens unit 34. The light source 31 outputs laser light L by, for example, a pulse oscillation method. The irradiation unit 3 may not have the light source 31, and may be configured to introduce the laser light L from outside the irradiation unit 3. The spatial light modulator 7 modulates the laser light L output from the light source 31. The condensing 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 light L from the spatial light modulator 7 toward the condenser lens 33. A pair of lenses 34A, 34B: a two-sided telecentric optical system in which the modulation surface 7a of the spatial light modulator 7 is in imaging relation with the entrance pupil surface (pupil surface) 33a of the condenser lens 33. Thus, the image of the laser light L on the modulation surface 7a of the spatial light modulator 7 (the image of the laser light L modulated by the spatial light modulator 7) is turned (imaged) on the entrance pupil surface 33a of the condenser lens 33. In addition, fs in the figure represents fourier surfaces.
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). The spatial light modulator 7 is configured by sequentially stacking a driving circuit layer 72, a pixel electrode layer 73, a reflective film 74, an alignment film 75, a liquid crystal layer 76, an alignment film 77, a transparent conductive film 78, and a transparent substrate 79 on a semiconductor substrate 71.
The semiconductor substrate 71 is, for example, a silicon substrate. The driving circuit layer 72 constitutes an active matrix (active matrix) circuit on the semiconductor substrate 71. The pixel electrode layer 73 includes a plurality of pixel electrodes 73a arranged in a matrix along the surface of the semiconductor substrate 71. Each pixel electrode 73a is formed of a metal material such as aluminum, for example. A voltage is applied to each pixel electrode 73a through the driving 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 side of the reflection film 74, and the alignment film 77 is provided on the surface of the liquid crystal layer 76 on the opposite side of the reflection film 74. The alignment films 75 and 77 are formed of a polymer material such as polyimide, for example, and rubbing (rubbing) is performed on the surfaces of the alignment films 75 and 77 in contact with the liquid crystal layer 76, for example. The alignment films 75 and 77 align the liquid crystal molecules 76a included in the liquid crystal layer 76 in a predetermined 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 through the liquid crystal layer 76 and the like. The transparent substrate 79 is, for example, a glass substrate. The transparent conductive film 78 is made of a material that is light-transmissive and conductive, such as ITO. The transparent substrate 79 and the transparent conductive film 78 penetrate the laser light 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 driving circuit layer 72, a voltage corresponding to the signal is applied to each pixel electrode 73a, and an electric field is formed between each pixel electrode 73a and the transparent conductive film 78. If the electric field is formed, the alignment direction of the liquid crystal molecules 76a changes for each region corresponding to the pixel electrode 73a in the liquid crystal layer 76, and the refractive index changes for each region corresponding to the pixel electrode 73 a. This state is a state in which a modulation pattern is displayed on the liquid crystal layer 76. The modulation pattern is used to modulate the laser light L.
That is, in a state where the liquid crystal layer 76 displays a modulation pattern, if the laser light L is incident on the liquid crystal layer 76 from the outside through the transparent substrate 79 and the transparent conductive film 78, reflected by the reflective film 74, and emitted from the liquid crystal layer 76 to the outside through the transparent conductive film 78 and the transparent substrate 79, the laser light L is modulated according to the modulation pattern displayed on the liquid crystal layer 76. In this way, according to the spatial light modulator 7, the laser light L (for example, modulation of the intensity, amplitude, phase, polarization, and the like of the laser light L) can be modulated by appropriately setting the modulation pattern displayed on the liquid crystal layer 76. 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 through the spatial light modulator 7 and the 4f lens unit 34, and is condensed in the object 11 by the condenser lens 33, and the modified region 12 and the crack extending from the modified region 12 are formed in the object 11 in the condensed region C. The control unit 6 controls the moving units 4 and 5 to move the light collecting region C relative to the object 11, thereby forming the modified region 12 and the crack along the movement direction of the light collecting region C.
[ description of findings about formation of oblique cracks ]
Here, the direction of the relative movement of the light collecting region C (the machining traveling direction) at this time is referred to as the X direction. The direction intersecting (orthogonal to) the 1 st plane 11a, which is the plane on which the laser beam L of the object 11 enters, is referred to as the Z direction. The direction intersecting (orthogonal to) the X direction and the Z direction is referred to as the Y direction. The X direction and the Y direction are directions along the 1 st plane 11 a. The Z direction may be defined as the optical axis of the condenser lens 33, and the optical axis of the laser beam L condensed toward the object 11 through the condenser lens 33.
As shown in fig. 5, the requirement is: in a cross surface (YZ surface S including the Y direction and the Z direction) intersecting the X direction, which is the machine direction, cracks are formed obliquely along a line RA inclined with respect to the Z direction and the Y direction (here, a line RA inclined at a predetermined angle θ from the Y direction). The inventors of the present invention have found that such oblique cracks are formed, and described with reference to examples of processing.
Here, modified regions 12a and 12b are formed as modified regions 12. Thereby, the crack 13a extending from the modified region 12a is connected to the crack 13b extending from the modified region 12b, and the crack 13 extending obliquely along the line RA is formed. Here, first, as shown in fig. 6, the 1 st surface 11a of the object 11 is set as the incident surface of the laser light L to form the condensed region C1. On the other hand, the condensed region C2 is formed on the 1 st surface 11a side of the condensed region C1 with the 1 st surface 11a being the incident surface of the laser light L. At this time, the light condensing region C2 is shifted (shift) by the distance Sz in the Z direction than the light condensing region C1, and is shifted by the distance Sy in the Y direction than the light condensing region C1. The distance Sz and the distance Sy correspond to the inclination of the line RA, for example.
On the other hand, as shown in fig. 7, the laser light L is modulated using the spatial light modulator 7 so that the beam shape in the YZ plane S of the condensed region C (at least the condensed region C2) becomes: at least on the 1 st surface 11a side of the center Ca of the light collecting region C, the tilt shape is tilted in the shift direction (here, the negative side in the Y direction) with respect to the Z direction. In the example of fig. 7, the following is given: an arc shape inclined toward the negative side in the Y direction with respect to the Z direction on the 1 st surface 11a side with respect to the center Ca, and inclined toward the negative side in the Y direction with respect to the Z direction on the opposite side of the 1 st surface 11a with respect to the center Ca. The beam shape of the light-condensing region C in the YZ plane S is the intensity distribution of the laser light L in the light-condensing region C in the YZ plane S.
As described above, by shifting at least two light-condensing regions C1 and C2 in the Y direction and forming at least the beam shape of the light-condensing region C2 (here, both the light-condensing regions C1 and C2) into an oblique shape, cracks 13 extending obliquely can be formed as shown in fig. 9 (a). For example, by controlling the modulation pattern of the spatial light modulator 7, the light converging regions C1 and C2 may be formed simultaneously by branching the laser light L to form the modified region 12 and the crack 13 (multi-focus processing), or the modified region 12a and the crack 13a may be formed by forming the light converging region C1 and then the modified region 12b and the crack 13b may be formed by forming the light converging region C2 (single-path processing).
Further, another light collecting region may be formed between the light collecting region C1 and the light collecting region C2, and thus, as shown in fig. 9 (b), another modified region 12C may be interposed between the modified region 12a and the modified region 12b, and a longer crack 13 extending obliquely may be formed.
Next, an understanding of the shape of the light flux in the YZ plane S of the light collecting region C to be an oblique shape will be described. First, the definition of the light condensing region C will be specifically described. Here, the light collecting region C is a region within a predetermined range from the center Ca (for example, a range of ±25 μm from the center Ca in the Z direction). As described above, the center Ca is the position where the beam intensity is highest or the center of gravity of the beam intensity. The position of the center of gravity of the beam intensity is, for example, a position on the optical axis of the laser beam L where the center of gravity of the beam intensity is located in a state where the modulation by the modulation pattern for shifting the optical axis of the laser beam L such as the modulation pattern for branching the laser beam L is not performed. The position of the highest beam intensity or 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 reduced to a level (lower than the processing threshold) where the modified region 12 is not formed in the object 11. The reflected light of the laser beam L from the surface (the 2 nd surface 11b in this case) opposite to the incident surface of the laser beam L on the object 11 is captured by a camera at a plurality of positions F1 to F7 in the Z direction as shown in fig. 15, for example. Thus, the position and the center of gravity of the highest beam intensity can be obtained based on the obtained image. Further, the modified region 12 is formed near the center Ca.
In order to set the beam shape in the light-condensing region C to an inclined shape, there is a method of shifting (offset) the modulation pattern. More specifically, the spatial light modulator 7 includes: a distortion correction pattern for correcting distortion of a wavefront, a grating (grating) pattern for branching laser light, a slit (slit) pattern, an astigmatic pattern, a coma aberration pattern, a spherical aberration correction pattern, and the like (a pattern in which these patterns are superimposed is displayed). As shown in fig. 8, the spherical aberration correction pattern Ps is shifted to adjust the beam shape of the light condensing region C.
In the example of fig. 8, the center Pc of the spherical aberration correction pattern Ps is shifted toward 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 on the modulation surface 7 a. 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 shift of the modulation surface 7a is a shift to the positive side in the Y direction in the entrance pupil surface 33a. That is, the center Pc of the spherical aberration correction pattern Ps is offset from the center Lc of the laser light L and the center of the entrance pupil plane 33a (which coincides with the center Lc here) by an offset amount Oy2 toward the positive side in the Y direction at the entrance pupil plane 33a.
As described above, the spherical aberration correction pattern Ps is shifted to deform the beam shape of the condensed region C of the laser beam L into an arc-like inclined shape as shown in fig. 7. As described above, shifting the spherical aberration correction pattern Ps corresponds to imparting coma aberration to the laser beam L. Therefore, the beam shape of the light condensing region C may be formed into an oblique shape by including the coma aberration pattern for imparting the coma aberration to the laser beam L in the modulation pattern of the spatial light modulator 7. Further, as the coma pattern, a pattern corresponding to 9 terms (Y component of 3 th order coma) of the Zernike polynomial, that is, a pattern in which coma occurs in the Y direction, may be used.
Next, an understanding of the relationship between the crystallinity of the object 11 and the crack 13 will be described. Fig. 10 is a schematic plan view of the object. Here, the object 11 is a silicon wafer (t 775 μm, <100>, 1 Ω·cm), and a notch (notch) 11d is formed. For the object 11, a 1 st processing example in which the X direction, which is the processing traveling direction, matches the 0 ° (110) plane is shown in fig. 11 (a), a 2 nd processing example in which the X direction matches 15 ° is shown in fig. 11 (b), a 3 rd processing example in which the X direction matches 30 ° is shown in fig. 12 (a), and a 4 th processing example in which the X direction matches the 45 ° (100) plane is shown in fig. 12 (b). In each processing example, the angle θ of the line RA in the YZ plane S from the Y direction was set to 71 °.
In each processing example, the modified region 12a and the crack 13a were formed by relatively moving the light collecting region C1 in the X direction as the 1 st path, and then the modified region 12b and the crack 13b were formed by relatively moving the light collecting region C2 in the X direction as the 2 nd path. The processing conditions of the 1 st and 2 nd paths are as follows. Note that CP below represents the intensity of the light condensing correction, and coma (LBA shift Y) represents the shift amount of the spherical aberration correction pattern Ps in the Y direction in pixel units of the spatial light modulator 7.
< 1 st Path >
Z direction position: 161 μm
CP：-18
And (3) outputting: 2W (2W)
Speed of: 530mm/s
Frequency: 80kHz
Coma (LBA offset Y): -5
Y direction position: 0
< route 2 >
Z direction position: 151 μm
CP：-18
And (3) outputting: 2W (2W)
Speed of: 530mm/s
Frequency: 80kHz
Coma (LBA offset Y): -5
Y direction position: 0.014mm
As shown in fig. 11 and 12, in any case, the crack 13 may be formed along a line RA inclined at 71 ° with respect to the Y direction. That is, cracks 13 extending obliquely along a desired line RA can be formed regardless of the crystal structure of the object 11, without being affected by the (110) plane, the (111) plane, the (100) plane, and the like, which are main cleavage planes of the object 11.
The control of the beam shape for forming such a crack 13 extending obliquely is not limited to the above example. Next, another example for forming the beam shape into an oblique shape will be described. As shown in fig. 13 (a), the laser beam L may be modulated by a modulation pattern PG1 that is asymmetric with respect to the axis Ax along the X direction, which is the machine direction, so that the beam shape of the light-condensing region C is inclined. The modulation pattern PG1 includes a grating pattern Ga on the negative side in the Y direction with respect to the axis Ax, and includes a non-modulation region Ba on the positive side in the Y direction with respect to the axis Ax, and the axis Ax passes through the center Lc of the beam spot of the laser light L in the Y direction and extends along the X direction. In other words, the modulation pattern PG1 includes the grating pattern Ga only on the positive side in the Y direction with respect to the axis Ax. Further, fig. 13 (b) inverts the modulation pattern PG1 of fig. 13 (a) so as to correspond to the entrance pupil plane 33a of the condenser lens 33.
Fig. 14 (a) shows the intensity distribution of the laser light L on the entrance pupil plane 33a of the condenser lens 33. As shown in fig. 14 (a), by using such a modulation pattern PG1, a portion modulated by the grating pattern Ga in the laser light L incident on the spatial light modulator 7 becomes not incident on the entrance pupil plane 33a of the condenser lens 33. As a result, as shown in fig. 14 (b) and 15, the beam shape of the light-condensing region C in the YZ plane S can be made to have an inclined shape inclined in one direction with respect to the Z direction as a whole.
That is, in this case, the beam shape of the light condensing region C becomes: the first surface 11a side is inclined with respect to the Z direction toward the negative side in the Y direction than the center Ca of the light collecting region C, and the second surface 11a side is inclined with respect to the Z direction toward the positive side in the Y direction than the center Ca of the light collecting region C. Further, each of fig. 15 (b) shows: the intensity distribution in the XY plane of the laser light L at each of the positions F1 to F7 in the Z direction shown in fig. 15 (a) is an actual observation result by a camera. In the case where the beam shape of the light-collecting region C is controlled in this way, the crack 13 extending obliquely can be formed in the same manner as in the above example.
As modulation patterns asymmetric to the axis Ax, modulation patterns PG2, PG3, and PG4 shown in fig. 16 may be used. The modulation pattern PG2 includes, on the negative side in the Y direction with respect to the axis Ax, a non-modulation region Ba and a grating pattern Ga arranged in this order in a direction away from the axis Ax, and includes, on the positive side in the Y direction with respect to the axis Ax, a non-modulation region 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 from the axis Ax.
The modulation pattern PG3 includes, on the negative side in the Y direction with respect to the axis Ax, the non-modulation region Ba and the grating pattern Ga sequentially arranged in the direction away from the axis Ax, and includes, on the positive side in the Y direction with respect to the axis Ax, the non-modulation region Ba and the grating pattern Ga sequentially arranged in the direction away from the axis Ax. In the modulation pattern PG3, the proportion of the non-modulation region Ba and the grating pattern Ga is made different between the positive side in the Y direction and the negative side in the Y direction (the non-modulation region Ba is narrowed relatively on the negative side in the Y direction) with respect to the axis Ax, and thus the non-modulation region Ba is asymmetric with respect to the axis Ax.
Like the modulation pattern PG2, the modulation pattern PG4 includes a 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, the region in which the grating pattern Ga is provided is further made a part in the X direction. That is, the modulation pattern PG4 includes, on the negative side of the axis Ax in the Y direction: the non-modulation region Ba, the grating pattern Ga, and the non-modulation region Ba are sequentially arranged in the X direction. Here, the grating pattern Ga is arranged in a region including the axis Ay along the Y direction passing through the center Lc of the beam spot of the laser light L in the X direction.
The beam shape of the light condensing region C can be set to be: at least on the 1 st surface 11a side with respect to the center Ca, a negative side in the Y direction with respect to the Z direction. That is, in order to control the beam shape of the light condensing region C to be inclined to the negative side in the Y direction with respect to the Z direction at least on the 1 st plane 11a side than the center Ca, asymmetric modulation patterns including the grating pattern Ga are used like the modulation patterns PG1 to PG4 or not limited to the modulation patterns PG1 to PG 4.
The asymmetric modulation pattern for forming the beam shape of the light-condensing region C into an oblique shape is not limited to the grating pattern Ga. Fig. 17 is a diagram showing another example of an asymmetric modulation pattern. As shown in fig. 17 (a), the modulation pattern PE includes an elliptical pattern Ew on the negative side in the Y direction with respect to the axis Ax, and includes an elliptical pattern Es on the positive side in the Y direction with respect to the axis Ax. Further, fig. 17 (b) inverts the modulation pattern PE of fig. 17 (a) so as to correspond to the entrance pupil plane 33a of the condenser lens 33.
As shown in fig. 17 (C), the elliptical patterns Ew and Es are each a pattern for forming the beam shape of the light condensing region C on the XY plane including the X direction and the Y direction into an elliptical shape having the X direction as the long side direction. However, the modulation intensity is different between the elliptical pattern Ew and the elliptical pattern Es. More specifically, the intensity of modulation by the elliptical pattern Es is larger than that by the elliptical pattern Ew. That is, the condensed region Cs formed by the laser light L modulated by the elliptical pattern Es has an elliptical shape longer in the X direction than the condensed region Cw formed by the laser light L modulated by the elliptical pattern Ew. Here, a relatively strong elliptical pattern Es is arranged on the negative side in the Y direction with respect to the axis Ax.
As shown in fig. 18 (a), by using such a modulation pattern PE, the beam shape of the light condensing region C in the YZ plane S can be made as follows: an inclined shape inclined toward the negative side in the Y direction with respect to the Z direction on the 1 st surface 11a side with respect to the center Ca. In particular, in this case, the beam shape of the light condensing region C in the YZ plane S may be: the opposite side of the 1 st surface 11a from the center Ca is inclined to the negative side in the Y direction with respect to the Z direction, and is curved as a whole. Further, each of fig. 18 (b) shows: the intensity distribution in the XY plane of the laser light L at each of the positions H1 to F8 in the Z direction shown in fig. 18 (a) is an actual observation result by a camera.
The modulation pattern for forming the beam shape of the light condensing region C into an oblique shape is not limited to the above asymmetric pattern. As an example, such a modulation pattern may be mentioned: as shown in fig. 19, the pattern of the laser beam L is modulated so that the focal point CI is formed at a plurality of positions on the YZ plane S, and the focal region C having an oblique shape is formed by the entire plurality of focal points CI (including the plurality of focal points CI). As an example of such a modulation pattern, it can be formed based on Axicon (Axicon lens) patterns. In the case of using such a modulation pattern, the modified region 12 itself may 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 in the other examples described above. Therefore, by using various modulation patterns, respectively, according to the requirements, desired processing can be performed.
The converging point CI is, for example, a point at which non-modulated laser light is converged. As described above, according to the findings of the present inventors, the crack 13 extending obliquely to the Z direction in the Y direction can be formed by shifting at least two modified regions 12a and 12b in the Y direction and the Z direction in the YZ plane S, and by forming the beam shape of the light collecting region C into an oblique shape in the YZ plane S.
In addition, when the beam shape is controlled, in the case of using the shift of the spherical aberration correction pattern, in the case of using the coma aberration pattern, and in the case of using the elliptical pattern, processing with high energy is possible as compared with the case of removing a part of the (cut) laser light by using the diffraction grating pattern. In addition, in these cases, it is effective to pay attention to the formation of cracks. In addition, in the case of using the coma aberration pattern, in the case of multi-focus processing, the beam shape of only a part of the light-condensing region can be made to be an oblique shape. In the case of using the axicon pattern, the use of another pattern is effective when the formation of the modified region is emphasized as compared with the other pattern.
[ example of finishing ]
Next, an example of the trimming process will be described. The trimming process is a process of removing unnecessary portions of the object 11. The trimming includes a laser processing method in which the condensed region is focused on the object 11 and the laser beam L is irradiated to form the modified region 12 on the object 11. 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 take various shapes. A functional element (not shown) is formed on the 2 nd surface 11b of the object 11. Examples of the functional element include a light receiving element such as a photodiode, a light emitting element such as a laser diode, and a circuit element such as a memory.
Fig. 20 and 21 are diagrams showing objects to be processed. As shown in fig. 20 and 21, an effective region R and a removal region E are set in the object 11. The effective region R is a portion corresponding to the obtained semiconductor element. The effective region R here is a disk-shaped portion including a central portion when the object 11 is viewed from the thickness direction. The removed region E is a region outside the effective region R of the object 11. The removed 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 removed area E includes a peripheral edge portion (a chamfered 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 by the control unit 6. The effective region R and the removed region E may be specified by coordinates.
The mounting table 2 is a support portion on which the object 11 is mounted. In the mounting table 2 of the present embodiment, the object 11 is mounted in a state where the 1 st surface 11a of the object 11 is the upper side (the 2 nd surface 11b is the lower side of the mounting table 2) which is the laser light incident surface side. The mounting table 2 has a rotation axis Cx provided at the center thereof. The rotation axis Cx is an axis extending in the Z direction. The mounting table 2 is rotatable about a rotation axis Cx. The mounting table 2 is rotationally driven by a 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 laser light L along the Z direction, and forms a modified region inside the object 11. The irradiation unit 3 is mounted on the moving unit 5. The irradiation unit 3 is linearly movable in the Z direction by a driving force of a known driving device such as a motor. The irradiation unit 3 is linearly movable in the X-direction and the Y-direction by a driving force of a known driving device such as a motor.
The irradiation unit 3 includes the spatial light modulator 7 as described above. The spatial light modulator 7 is configured as a shaping unit that shapes a light-collecting region C in a plane perpendicular to the optical axis of the laser beam L (i.e., the shape of the light-collecting region C when viewed from the Z direction) (hereinafter also referred to as "beam shape"). The spatial light modulator 7 can shape the laser beam L so that the beam shape when viewed from the Z direction has a longitudinal direction. For example, the spatial light modulator 7 displays a modulation pattern for shaping the beam shape into an elliptical shape, thereby shaping the beam shape into 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 round shape, an oblong shape, or a rectangular shape. The beam shape may be a long triangle, rectangle or polygon. The modulation pattern of the spatial light modulator 7 for realizing the beam shape may include at least one of a slit pattern and an astigmatism pattern. When the laser beam L has a plurality of light-collecting regions C due to astigmatism or the like, the shape of the light-collecting region C on the most upstream side of the optical path of the laser beam L among the plurality of light-collecting regions C is the beam shape of the present embodiment (the same applies to other laser beams). The longitudinal direction is the longitudinal direction of the elliptical shape of the beam shape, and is also referred to as the elliptical longitudinal direction.
The beam shape is not limited to the shape of the light collection point, and may be a shape near the light collection point, as long as it is a shape of a part of the light collection region C. For example, in the case of the laser beam L having astigmatism, as shown in fig. 22 (a), the beam shape has a longitudinal direction NH in a region on the laser light incidence surface side in the vicinity of the converging point. The beam intensity distribution in the plane of the beam shape of fig. 22 (in the plane of the Z-direction position on the laser light incidence surface side in the vicinity of the converging point) has a strong intensity distribution in the long-side direction NH, and the direction in which the beam intensity is strong coincides with the long-side direction NH.
In the case of the laser beam L having astigmatism, as shown in fig. 22 (c), the beam shape has a longitudinal direction NH0 perpendicular to the longitudinal direction NH (see fig. 22 (a)) of the region on the side of the laser beam incidence surface in the vicinity of the converging point. The beam intensity distribution in the plane of the beam shape of fig. 22 (c) (in the plane of the Z-direction position on the opposite surface side to the laser light incident surface side in the vicinity of the converging point) becomes a strong intensity distribution in the longitudinal direction NH0, and 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 condensed region C is formed in a circular shape having no longitudinal direction in a region between the laser light incident surface side and the opposite surface side in the vicinity of the condensed point.
In the case of the laser beam L having such astigmatism, the condensing region C to be the object of the present embodiment includes a region on the laser light incident surface side in the vicinity of the condensing point, and the beam shape to be the object of the present embodiment is the beam shape shown in fig. 22 (a).
The modulation pattern of the spatial light modulator 7 is adjusted so that the position of the beam shape shown in fig. 22 (a) which becomes the light condensing region C can be arbitrarily controlled. For example, the region on the opposite side of the laser light incident surface in the vicinity of the converging point can be controlled to have a beam shape shown in fig. 22 (a). For example, the area between the laser light incident surface side and the opposite surface side near the converging point can be controlled to have a beam shape shown in fig. 22 (a). The position of a part of the light-condensing region C is not particularly limited as long as it is located anywhere from the laser light incident surface of the object 11 to the opposite surface thereof.
In addition, for example, in the case of using a slit or an elliptical optical system due to control of a modulation pattern and/or a mechanical mechanism, as shown in fig. 23 (a), the beam shape has a longitudinal direction NH in a region on the laser light incident surface side in the vicinity of the converging point. The beam intensity distribution in the plane of the beam shape of fig. 23 (in the plane of the Z-direction position on the laser light incidence surface side in the vicinity of the converging point) has a strong intensity distribution in the long-side direction NH, and the direction in which the beam intensity is strong coincides with the long-side direction NH.
When a slit or an elliptical optical system is used, as shown in fig. 23 (c), the beam shape of the region on the opposite surface side of the laser light incident surface in the vicinity of the converging point has the same longitudinal direction NH as the longitudinal direction NH of the region on the laser light incident surface side (see fig. 22 (a)). The beam intensity distribution in the plane of the beam shape of fig. 23 (c) (in the plane of the Z-direction position on the opposite surface side to the laser light incidence surface side in the vicinity of the converging point) has a strong intensity distribution in the longitudinal direction NH, and 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 (b), the beam shape has a longitudinal direction NH0 perpendicular to the longitudinal direction NH of the region on the laser light incident surface side (see fig. 23 (a)) at the converging point. The beam intensity distribution in the plane of the beam shape of fig. 23 (in the plane of the Z-direction position of the converging point) becomes a strong intensity distribution in the long-side direction NH0, and the direction in which the beam intensity is strong coincides with the long-side direction NH0.
When such a slit or elliptical optical system is used, the beam shape other than the focal point has a shape in the longitudinal direction, and the beam shape other than the focal point is the beam shape to be subjected to the present embodiment. That is, a part of the converging region C to be subjected to the present embodiment includes a region on the laser light incident surface side in the vicinity of the converging point, and the beam shape to be subjected to the present embodiment is the beam shape shown in fig. 23 (a).
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 condensed region C. The control unit 6 can perform various controls based on rotation information (hereinafter also referred to as "θ information") related to the rotation amount of the mounting table 2. The θ information may be obtained by a driving amount of a driving device that rotates the stage 2, or may be obtained by another sensor or the like. The θ information can be obtained by various known techniques. Here, the θ information includes a rotation angle based on a state when the object 11 is positioned in the 0 ° direction.
The control unit 6 controls the start and stop of the irradiation of the laser light L by the irradiation unit 3 based on θ information in a state where the light collecting region C is located at a position along the line a (the peripheral edge of the effective region R) of the object 11 while rotating the stage 2, thereby performing peripheral edge processing for forming a modified region along the peripheral edge of the effective region R.
The control unit 6 irradiates the removal region E with the laser beam L without rotating the stage 2, and moves the condensed region C of the laser beam L to perform the removal process of forming the modified region in the removal region E.
The control unit 6 controls at least one of rotation of the stage 2, irradiation of the laser light L from the irradiation unit 3, and movement of the light collecting region C so that the pitch of the plurality of modification points included in the modification region (the interval between the modification points adjacent in the machining traveling direction) becomes constant.
The control unit 6 obtains a reference position (position in the 0 ° direction) of the rotation direction of the object 11 and the diameter of the object 11 from a captured image of a positioning camera (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 onto the rotation axis Cx of the mounting table 2.
Next, an example of the trimming process will be described. First, the object 11 is placed on the stage 2 so that the 1 st surface 11a becomes an incident surface of the laser light L. A support substrate or a tape material is bonded to the 2 nd surface 11b side of the object 11 on which the functional element is mounted, and is protected.
Then, trimming is performed. In the trimming process, the peripheral edge processing is performed by the control unit 6. Specifically, as shown in fig. 24 (a), the irradiation of the laser light L by the irradiation unit 3 is controlled to be started and stopped based on θ information while the mounting table 2 is rotated at a constant speed and the light collecting region C is positioned at a position along the peripheral edge of the effective region R of the object 11. As a result, as shown in fig. 24 b and 24 c, the modified region 12 is formed along the line a (the peripheral edge of the effective region R). The modified region 12 includes modified points and cracks extending from the modified points.
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 to the removal region E without rotating the stage 2, the irradiation unit 3 is moved in the X direction, and the condensed region C of the laser beam L is moved relative to the object 11 in the X direction. After rotating the stage 2 by 90 °, the laser beam L is irradiated to the removal region E, and the irradiation unit 3 is moved in the X direction, so that the condensed region C of the laser beam L is moved relative to the object 11 in the X direction.
As shown in fig. 25 (b), the modified region 12 is formed along a line extending so that the removed region E is equally divided by 4 when viewed in the Z direction. The modified region 12 includes modified points and cracks extending from the modified points. The crack may reach at least any one of the 1 st surface 11a and the 2 nd surface 11b, or may not reach at least any one of the 1 st surface 11a and the 2 nd surface 11 b. Then, as shown in fig. 26 (a) and 26 (b), the removal region E is removed by, for example, a jig or air with the modified region 12 as a boundary. Thereby, the semiconductor element 11K is formed from the object 11.
Next, as shown in fig. 26 (c), the peeling surface 11c of the semiconductor element 11K is polished with a polishing material KM such as grinding or whetstone. In the case of peeling the object 11 by etching, the polishing can be simplified. As a result, the semiconductor element 11M is obtained.
Next, the trimming process will be described in more detail. As shown in fig. 27, the object 11 has a plate shape. Object 11 has a crystal structure, and includes: (100) A plane, one (110) plane, the other (110) plane, a 1 st crystal orientation K1 orthogonal to the one (110) plane, and a 2 nd crystal orientation K2 orthogonal to the other (110) plane. The 1 st surface 11a of the object 11 is a (100) surface. The object 11 is supported on the stage 2 so that the (100) plane (i.e., the 1 st plane 11 a) becomes the plane on which the laser light L enters. The object 11 is, for example, a silicon wafer formed of silicon. The (110) plane is a cleavage plane. The 1 st crystal orientation K1 and the 2 nd crystal orientation K2 are directions of cleavage, that is, directions in which the cleavage in the object 11 is most easily extended. The 1 st crystal orientation K1 and the 2 nd crystal orientation K2 are orthogonal to each other.
The object 11 is provided with a registration object 11n. For example, the position of the alignment object 11n in the θ direction (the rotation direction of the table 2 about the rotation axis Cx) relative to the 0 ° direction of the object 11 has a certain relationship. The position in the 0 ° direction refers to the position of the object 11 serving as the reference in the θ direction. For example, the alignment object 11n is a notch formed in the outer edge portion. The alignment object 11n is not particularly limited, and may be an orientation plane of the object 11 or a pattern of functional elements. In the example of the icon, the alignment object 11n is provided at a position in the 0 ° direction of the object 11. In other words, the alignment object 11n is provided at a position where the outer edge of the object 11 is orthogonal to the 2 nd crystal orientation K2.
A line a as a trimming predetermined line is set in the object 11. Line a is a line intended to form modified region 12. Line a extends in a loop inside the outer edge of object 11. The line a here extends in a circular shape. 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 may be an actually drawn line. Line a may also be designated for coordinates.
The control unit 6 acquires object information about the object 11. The object information includes, for example, information about the crystal orientations (1 st crystal orientation K1 and 2 nd crystal orientation K2) of the object 11, positional information about the position of the object 11 in the 0 ° direction, and the diameter of the object 11. The control unit 6 can acquire object information based on a captured image of the alignment camera, and input of a user operation, communication from the outside, or the like.
The control unit 6 obtains line information about the line a. Line information comprising: information on the line a, and information on a moving direction (also referred to as "machining traveling direction") of the movement when the light collecting region C is relatively moved along the line a. For example, the machine direction is a 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 operation of a user or an input from an external communication or the like.
The control unit 6 determines the direction of the longitudinal direction when the light-collecting region C is relatively moved along the line a, based on the acquired object information and line information, and makes the longitudinal direction of the beam shape intersect with the machine direction. Specifically, the control unit 6 determines the orientation of the longitudinal direction NH as the 1 st orientation and the 2 nd orientation based on the object information and the line information. The 1 st direction is a direction along the longitudinal direction of the beam shape when the light-condensing region C is relatively moved along the 1 st region A1 of the line a. The 2 nd direction is a direction along the longitudinal direction of the beam shape when the light-condensing region C is relatively moved along the 2 nd region A2 of the line a. Hereinafter, the "direction of the long side of the beam shape" will also be referred to as "direction of the beam shape".
The 1 st region A1 is a circular arc-shaped region, and as an example, when the point at which the 2 nd crystal orientation K2 is orthogonal to the line a is 0 °, the point at which the 1 st crystal orientation K1 is orthogonal to the line a is 90 °, and the point at the middle between the 0 ° and 90 ° of the line a is 45 °, the method includes: a region from 0 ° to 45 °, a region from 90 ° to 135 °, a region from 180 ° to 225 °, and a region from 270 ° to 315 °, A2 nd region A2 being a circular arc-shaped region, comprising: a region from 45 ° to 90 °, a region from 135 ° to 180 °, a region from 225 ° to 270 °, and a region from 315 ° to 360 °. In this case, the point at 45 ° and the point at 225 ° are the point at which the 3 rd crystal orientation K3 perpendicular to the (100) plane is perpendicular to the line a, and the point at 135 ° and the point at 315 ° are the point at which the 4 th crystal orientation K4 perpendicular to the (100) plane is perpendicular to the line a.
As described above, the line a includes: a plurality of 1 st areas A1 and a plurality of 2 nd areas A2 are alternately arranged every 45 ° around the counterclockwise direction. However, the above-described angle ranges of the 1 st region A1 and the 2 nd region A2 can be arbitrarily changed depending on where the 0 ° point is set. For example, when the point at which the 1 st crystal orientation K1 is perpendicular to the line a is set to 0 ° (when the above-mentioned point at 90 ° is set to 0 °), the 1 st region A1 and the 2 nd region A2 are angular ranges rotated by 90 ° from the above-mentioned angular ranges. In the case where the 0 ° point is set as described above, the point rotated 45 ° clockwise from the 0 ° point, that is, the 315 ° point may be changed to the-45 ° point. The point of the boundary (for example, 45 °) between the 1 st region A1 and the 2 nd region A2 may be included in either or both of the 1 st region A1 and the 2 nd region A2.
The 1 st region A1 includes a region in which a processing angle to be described later is 0 ° to 45 ° or more and 45 ° or less, or-90 ° to-45 ° or less, when the light-collecting region C is relatively moved along the line a. The 2 nd region A2 includes a region having a processing angle of 45 ° or more and less than 90 ° or-45 ° or more and less than 0 ° when the light-collecting region C is relatively moved along the line a.
As shown in fig. 28 (b), the working angle α is an angle of the working direction ND with respect to the 1 st crystal orientation K1. The machining angle α is a positive (+) angle and a negative (-) angle with respect to a counterclockwise angle as viewed from the Z direction intersecting the 1 st plane 11a, which is the incident plane of the laser beam L. The machining angle α can be obtained based on θ information, object information, and line information of the stage 2. The case where the light collecting region C is relatively moved along the 1 st region A1 can be considered as a case where the machining angle α is, for example, 0 ° to 45 ° or less or-90 ° to-45 ° or less. The case where the light collecting region C is relatively moved along the 2 nd region A2 can be considered as a case where the machining angle α is, for example, 45 ° to 90 ° or less or-45 ° to 0 ° or less.
The 1 st and 2 ND orientations are orientations of directions inclined with respect to the machine direction ND so as to approach the larger angle (the farther one) between the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 and the machine direction ND.
The 1 st and 2 nd orientations are as follows when the machining angle α is 0 ° to 90 °. The 1 st direction is a direction in which the longitudinal direction NH is inclined toward the side closer to the 2 ND crystal orientation K2 with respect to the machine direction ND. The 2 ND direction is a direction in which the longitudinal direction NH is inclined toward the side closer to the 1 st crystal orientation K1 with respect to the machine direction ND. The 1 st direction is, for example, a direction inclined from the machine direction ND to a direction approaching the 2 ND crystal orientation K2 by 10 ° to 35 °. The 2 ND direction is, for example, a direction inclined from the machine direction ND to a direction approaching the 1 st crystal orientation K1 by 10 ° to 35 °.
The 1 st direction is the direction of the condensed region C in the case where the beam angle β is +10° to +35°. The 2 nd direction is the direction of the condensing region C in the case where the beam angle β is-35 ° to-10 °. The beam angle β is an angle between the machine direction ND and the longitudinal direction NH. The beam angle β is an angle of positive (+) with respect to the counterclockwise direction and an angle of negative (-) with respect to the clockwise direction, as viewed from the Z direction intersecting the 1 st plane 11a, which is the incident plane of the laser beam L. The beam angle β can be obtained based on the direction of the light-collecting region C and the machine direction ND.
The control unit 6 controls the start and stop of laser processing on the object 11. The control unit 6 performs the 1 st processing for forming the modified region 12 by relatively moving the condensed region C along the 1 st region A1 of the line a, and stopping the formation of the modified region 12 in a region other than the 1 st region A1 of the line a. The control unit 6 performs the 2 nd processing for forming the modified region 12 by relatively moving the condensed region C along the 2 nd region A2 of the line a, and stopping the formation of the modified region 12 in a region other than the 2 nd region A2 of the line a.
The formation of the modified region 12 of the control unit 6 and the switching of the stop thereof can be realized as follows. For example, in the irradiation section 3, the start and stop (ON/OFF) of the irradiation (output) of the laser light L are switched, so that the formation of the modified region 12 and the stop of the formation can be switched. Specifically, when the laser oscillator is configured by a solid-state laser, the ON/OFF of a Q-switch (AOM (acoustic optical modulator), EOM (electro optical modulator), or the like) provided in the resonant cavity is switched, and the start and stop of the irradiation of the laser light L are switched at high speed. When the laser oscillator is configured by a fiber laser, the ON/OFF of the output of the semiconductor laser constituting the seed laser and the amplifier (excitation) laser is switched, and the start and stop of the irradiation of the laser light L are switched at high speed. When an external modulation element is used for the laser oscillator, ON/OFF of the external modulation element (AOM, EOM, etc.) provided outside the resonant cavity is switched, so that ON/OFF of irradiation of the laser light L is switched at high speed.
Alternatively, the formation of the modified region 12 by the control unit 6 and the switching of the stop thereof can be realized as follows. For example, a mechanical mechanism such as a shutter may be controlled to close the optical path of the laser beam L, thereby switching between formation of the modified region 12 and stop of the formation. The laser light L may be switched to CW light (continuous wave) to stop the formation of the modified region 12. The formation of the modified region 12 may be stopped by displaying the condensed state of the laser light L in a pattern (for example, a pattern of a rough pattern that disperses the laser light) in a state where the condensed state cannot be modified on the liquid crystal layer 76 of the spatial light modulator 7. The output adjustment unit such as an attenuator may be controlled to reduce the output of the laser beam L so that the modified region 12 cannot be formed, and the formation of the modified region 12 may be stopped. The formation of the modified region 12 may also be stopped by switching the polarization direction. The formation of the modified region 12 may be stopped by scattering (scattering) and cutting the laser light L in directions other than the optical axis.
The control unit 6 controls the spatial light modulator 7 to adjust the orientation of the light condensing region C. When the 1 st machining process is performed, the control unit 6 adjusts the orientation of the light collecting region C so as to be the 1 st orientation. When the 2 nd processing is performed, the control unit 6 adjusts the orientation of the light collecting region C so as to be the 2 nd orientation. The control unit 6 adjusts the longitudinal direction NH of the light collecting region C so that the machine direction ND varies within a range of ±35°, as an example.
The laser processing apparatus 1 performs the following trimming processing.
In the trimming process, first, the stage 2 is rotated and the irradiation section 3 on which the camera is mounted is moved in the X direction and the Y direction so that the camera for alignment is positioned directly above the alignment target 11n of the target 11 and the focal point of the camera is matched with the alignment target 11 n.
Then, the alignment camera performs photographing. The position of the object 11 in the 0 ° direction is obtained based on the captured image of the camera. The control unit 6 obtains object information and line information based on the captured image of the camera, and input of a user operation, communication from the outside, or the like. The object information contains alignment information on the position and diameter of the object 11 in the 0 ° direction. As described above, since the position of the alignment object 11n has a constant relationship in the θ direction with respect to the position in the 0 ° direction, the position of the alignment object 11n is obtained from the captured image, and the position in the 0 ° direction can be obtained. Based on the captured image of the camera, the diameter of the object 11 can be obtained. The diameter of the object 11 may be set by a user's input.
Next, based on the acquired object information and line information, the control unit 6 determines the 1 st direction and the 2 nd direction, which are the directions of the longitudinal direction NH of the light collecting region C when the light collecting region C is relatively moved along the line a.
Subsequently, the stage 2 is rotated to position the object 11 in the 0 ° direction. In the X direction, the irradiation unit 3 is moved in the X direction and the Y direction so that the light collecting region C is positioned at a predetermined trimming position. The trimming predetermined position is, for example, a predetermined position on the line a of the object 11.
Then, the rotation of the mounting table 2 is started. The following of the 1 st surface 11a of the distance measuring sensor (not shown) is started. Further, before the tracking start of the range sensor, it is confirmed in advance that the position of the light condensing region C is within a range detectable by the range sensor. At a point in time when the rotation speed of the mounting table 2 is fixed (constant speed), the irradiation of the laser beam L by the irradiation unit 3 is started.
The control unit 6 switches ON/OFF of the irradiation of the laser beam L while rotating the stage 2, thereby forming the modified region 12 by relatively moving the condensed region C along the 1 st region A1 in the line a as shown in fig. 28 (a), and stopping the formation of the modified region 12 in the region other than the 1 st region A1 of the line a (1 st processing step). As shown in fig. 28 (b), when the 1 st machining step is performed, the control unit 6 adjusts the orientation of the light-collecting region C to the 1 st orientation. That is, the orientation of the light condensing region C in the 1 st working step is fixed to be the 1 st orientation.
Next, by switching ON/OFF of the irradiation of the laser light L by the control unit 6 while rotating the stage 2, as shown in fig. 29 (a), the light-collecting region C is relatively moved along the 2 nd region A2 in the line a to form the modified region 12, and the formation of the modified region 12 is stopped in the region other than the 1 st region A1 of the line a (the 2 nd processing step). As shown in fig. 29 (b), when the 2 nd processing step is performed, the control unit 6 adjusts the orientation of the light-collecting region C to the 2 nd orientation. That is, the orientation of the light condensing region C in the 2 nd working step is fixed to be the 2 nd orientation.
The 1 st and 2 nd working steps are repeated while changing the position in the Z direction of the trimming predetermined position. As described above, the modified regions 12 are formed in a plurality of rows in the Z direction along the line a of the peripheral edge of the effective region R inside the object 11.
[ embodiment 1 of laser processing ]
The above description has been made with respect to an example of the findings about the formation of oblique cracks and the trimming process. Here, an embodiment of laser processing for forming oblique cracks during trimming processing will be described. Fig. 30 is a diagram showing an object to be laser-processed according to an embodiment. Fig. 30 (a) is a plan view, and fig. 30 (b) is a side view. Fig. 31 is a cross-sectional view of the object shown in fig. 30.
As shown in fig. 30 and 31, the object 100 includes: the object 11 and an object 11R which is a member different from the object 11. The object 11R is, for example, a silicon wafer. Object 11 includes a plurality of functional elements, and element layer 110 formed on 2 nd surface 11 b. The object 11R includes a plurality of functional elements, and includes an element layer 110R formed on the 1 st surface 11Ra of the object 11R. The object 11 and the object 11R are arranged so that the element layers 110 and 110R face each other, and are bonded to each other so as to be bonded to each other, thereby forming the object 100.
Here, a modified region 12 and a crack 13 extending from the modified region 12 are formed in the object 11, and a trimming process is performed to cut off a removal region E of the object 11 with the modified region 12 and the crack 13 as boundaries. More specifically, object 11 includes: the 1 st portion 15A and the 2 nd portion 15B are arranged in this order from the 2 nd surface 11B (opposite surface) side opposite to the 1 st surface 11a of the incident surface of the laser light L. In addition, in the 1 st portion 15A, the modified region 12 is formed so as to form a crack 13 extending obliquely to the Z direction (hereinafter referred to as an "oblique crack"), and in the 2 nd portion 15B, the modified region 12 is formed so as to form a crack 13 extending along the Z direction (hereinafter referred to as a "vertical crack"). The line R1 in fig. 31 is a predetermined line for forming an oblique crack, and the line R2 is a predetermined line for forming a vertical crack.
At least in the processing of the 1 st portion 15A, the trimming processing is used together with the processing for generating oblique cracks. That is, at the time of processing the 1 st portion 15A, the long side direction NH is formed to be inclined with respect to the processing direction ND so as to approach the larger angle between the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 and the processing direction ND, and the modified region 12 and the crack 13 are formed along the line a, and the crack 13 is formed as an oblique crack.
More specifically, when the 1 st region A1 of the line a is processed, as shown in fig. 28 (b), the laser beam L is shaped so as to form A1 st-oriented 1 st shape Q1 of the condensed region C, and when the 2 nd region A2 of the line a is processed, as shown in fig. 29 (b), the laser beam L is shaped so as to form A2 nd-oriented 2 nd shape Q2 of the condensed region C. 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. 30. As shown in fig. 32, in the line a, the cross-sectional view is actually performed by processing the 2 nd region A2 from the point of 0 ° which is the intersection point of the line a and the 2 nd crystal orientation K2, to the point of-45 ° which is the intersection point of the line a and the 4 th crystal orientation K4, in the following cases: the light-collecting region C is moved relatively by setting the machine direction ND to the forward direction ND1, and the light-collecting region C is moved relatively by setting the machine direction ND to the reverse direction ND 2. Here, since the processing of the 2 nd region A2 is performed, the light collecting region C has A2 nd shape Q2 as shown in fig. 29 (b). The extending direction CD of the oblique crack is a direction from the center side of the object 11 toward the outside (see fig. 29 (b)).
Then, as shown in fig. 29 (b), when the machining traveling direction ND is the forward direction ND1, the direction of inclination of the long-side direction NH of the light collecting region C with respect to the machining traveling direction ND is the same as the direction of extension CD of the oblique crack, whereas when the machining traveling direction ND is the reverse direction ND2 (when the direction of the arrow of the machining traveling direction ND is reversed), the direction of inclination of the long-side direction NH with respect to the machining traveling direction ND and the direction of extension CD of the oblique crack are opposite to each other. The clockwise direction ND1 is a counterclockwise direction, and the reverse direction ND2 is a clockwise direction.
Fig. 33 and 34 are sectional photographs showing the processing results. Fig. 33 shows the results of processing in the forward direction ND1, and (a) to (d) are photographs of the cross-section of points of 0 °, 15 °, 30 °, and 45 °. Fig. 34 shows the results of the processing in the reverse direction ND2, and (a) to (d) are photographs of the cross-section of points at 0 °, 15 °, 30 °, and 45 °.
As shown in fig. 33 and 34, although good machining results were obtained from 0 ° to-45 ° in the forward direction ND1 in which the direction of the longitudinal direction NH and the direction of extension CD of the oblique crack were on the same side as the machining traveling direction ND, in the reverse direction ND2 in which the direction of the longitudinal direction NH and the direction of extension CD of the oblique crack were on opposite sides as the machining traveling direction ND, at the point of-45 ° (fig. 34 (d)), the irregularities FN reaching the lower surface were generated, and quality degradation was confirmed. From this, it can be understood that the relation between the direction in which the longitudinal direction NH is inclined with respect to the machine direction ND and the direction CD in which the oblique crack extends with respect to the machine direction ND affects the machine quality. Based on this understanding, other processing tests were performed.
Fig. 35 is a schematic view for explaining a processing test. Fig. 36 is a schematic view showing a relationship between a machining traveling direction in a machining test and a beam shape and an oblique crack. As shown in fig. 35 and 36, in the machining test, when viewed from the Z direction, the direction of the (110) plane is set to 45 ° as the machining traveling direction ND, and the forward direction ND1 and the reverse direction ND2 are each machined so that the extending direction CD of the oblique crack becomes the forward direction CD1 and the reverse direction CD 2. That is, the processing (eight sets of processing) is further performed in which the beam shape of the light-collecting region C is set to the 1 st shape Q1 and the 2 ND shape Q2 for the combination of four sets, with the forward and backward directions of the processing traveling direction ND being a pair and the forward and backward directions of the oblique crack extending direction CD being a pair.
Fig. 37 is a table showing the results of the processing tests shown in fig. 35 and 36. As shown in fig. 37, for the total of eight sets of processing, when the extending direction CD of the oblique crack is the positive direction CD1, good processing results are obtained when the beam shape of the light collecting region C is set to the 2 ND shape Q2 and the processing traveling direction ND is set to the forward direction ND1, and when the beam shape of the light collecting region C is set to the 1 st shape Q1 and the processing traveling direction ND is set to the reverse direction ND2 (table "a" in fig. 37).
In addition, for the processing of the total eight groups, when the extending direction CD of the oblique crack is set to the reverse direction CD2, good processing results are obtained when the beam shape of the light-collecting region C is set to the 1 st shape Q1 and the processing traveling direction ND is set to the forward direction ND1, and when the beam shape of the light-collecting region C is set to the 2 ND shape Q2 and the processing traveling direction ND is set to the reverse direction ND 2. As a result, it can be understood that, at least when machining is performed at a point of 45 °, the forward and reverse directions of the machining traveling direction ND are adjusted, and that, when the longitudinal direction NH of the light collecting region C is inclined toward the same side as the oblique crack extending direction CD with respect to the machining traveling direction ND, a good machining result can be obtained.
In the case where the point at 45 ° is 0 ° with respect to the point at which the 2 nd crystal orientation K2 is orthogonal to the line a, the point at which the 3 rd crystal orientation K3 is orthogonal to the (100) plane is orthogonal to the line a, and similarly, the point at which the 4 th crystal orientation K4 is orthogonal to the (100) plane is orthogonal to the line a, that is, -45 ° is equivalent.
Based on the above findings, further processing tests were performed. Fig. 38 is a table showing the results of the processing test. Among the conditions shown in the table of fig. 38, the condition that the beam shape is set to the 1 st shape Q1 in the 1 st region A1 and the condition that the beam shape is set to the 2 ND shape Q2 in the 2 ND region A2, that is, the condition IR1 and the condition IR2 that the longitudinal direction NH of the light collecting region C is inclined toward the same side as the extending direction CD of the oblique crack with respect to the processing traveling direction ND, can obtain good processing results (evaluation "a" or evaluation "B" of the table of fig. 38). The evaluations shown in fig. 38 were performed in the order of evaluation "a", evaluation "B", evaluation "C", evaluation "D", and evaluation "E" (i.e., evaluation "a" was the most favorable and evaluation "E" was the least favorable).
The condition IR1 is that, when the point at which the 1 st crystal orientation K1 is orthogonal to the line a is 0 °, the machine direction ND is set to the forward direction ND1 and the beam shape of the light-collecting region C is set to the 2 ND shape Q2 for the 2 ND region A2 from the point of 0 ° to the point of-45 °. In addition, the condition IR2 is a condition that, when the point at which the 1 st crystal orientation K1 is orthogonal to the line a is 0 °, the machining traveling direction ND is the reverse direction ND2 and the beam shape of the light-collecting region C is the 1 st shape Q1 for the 1 st region A1 from the point of-45 ° to the point of-90 °.
On the other hand, in the respective conditions shown in the table of fig. 38, as long as the condition that the beam shape is made 1 st shape Q1 in the 1 st region A1 and the beam shape is made 2 ND shape Q2 in the 2 ND region A2, even the condition IR3 and the condition IR4 that the longitudinal direction NH of the light collecting region C is inclined toward the different side from the extending direction CD of the oblique crack with respect to the machine direction ND, although the conditions are inferior to the condition IR1 and the condition IR2, substantially good machining results can be obtained except for the point of-45 °. On the other hand, in the conditions shown in the table of fig. 38, the condition IR5 in which the beam shape is set to the 2 ND shape Q2 in the 1 st region A1 and the condition IR6 in which the beam shape is set to the 1 st shape Q1 in the 2 ND region A2 are not all satisfactory results regardless of the forward and backward directions of the machining traveling direction ND.
Fig. 39 (a) is an example of a cross-sectional photograph corresponding to the evaluation "E" in the table of fig. 38, fig. 39 (B) is an example of the evaluation "D" in the table of fig. 38, fig. 39 (C) is an example of the evaluation "C" in the table of fig. 38, fig. 39 (D) is an example of the evaluation "B" in the table of fig. 38, and fig. 39 (E) is an example of the cross-sectional photograph corresponding to the evaluation "a" in the table of fig. 38. As shown in fig. 39, evaluation "a" and evaluation "B" showed that the irregularities were not formed to the following good processing results. The evaluation "C" showed that the irregularities reaching the lower surface slightly occurred, but the evaluation was substantially good. On the other hand, the evaluation "D" and the evaluation "E" relatively produced a large number of irregularities reaching the lower surface, and showed poor results.
From the results of the processing tests shown in fig. 38 and 39, it was confirmed that the findings obtained from the results of the processing tests shown in fig. 37 were correct.
In the present embodiment, laser processing is performed based on the above findings. Here, first, the 1 st portion 15A (see fig. 31) of the object 11 is processed. That is, by switching ON/OFF of the irradiation of the laser light L by the control unit 6 while rotating the stage 2, as shown in fig. 40 a, the light-collecting region C is relatively moved along the 1 st region A1 in the line a to form the modified region 12, and the formation of the modified region 12 is stopped in the region (2 nd region A2) other than the 1 st region A1 of the line a (1 st processing).
As shown in fig. 40 (b), in the 1 st machining, the rotation direction of the table 2 is controlled by the moving unit 4 of the control unit 6, so that the machining traveling direction ND becomes the reverse direction ND2. Since the 1 st process is the process of the 1 st region A1, the laser beam L by the spatial light modulator 7 is formed under the control of the control unit 6, and the beam shape of the light-condensing region C is set to the 1 st shape Q1. Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the Z direction from the center of the object 11 toward the 2 nd surface 11b toward the outside (see fig. 31).
The method for forming the oblique crack will be specifically described herein. That is, in the 1 st processing, as shown in fig. 41, the position of the light-collecting region C1 is set at the 1 st Z position Z1 with respect to the Z direction intersecting the 1 st surface 11a, which is the incident surface of the laser beam L1 of the object 11, and the light-collecting region C1 is relatively moved along the line a (X direction), whereby the modified region (1 st modified region) 12a and the crack (1 st crack) 13a (1 st formation) extending from the modified region 12a are formed in the object 11. In the 1 st formation, the position of the light condensing region C1 is set at the 1 st Y position Y1 for the Y direction along the 1 st surface 11a and intersecting the X direction.
In the 1 st process, the position of the condensed region C2 of the laser beam L2 is set to a 2 nd Z position Z2 on the 1 st plane 11a (incidence plane) side of the 1 st Z position Z1 of the condensed region C1 formed in the 1 st process, and the condensed region C2 is relatively moved along the line a (X direction), thereby forming a modified region 12b (2 nd modified region) and a crack (2 nd crack) 13b (2 nd formation) extending from the modified region 12 b. In this formation 2, the position of the light-condensing region C2 is formed at a 2 nd Y position Y2 shifted from the 1 st Y position Y1 of the light-condensing region C1 with respect to the Y direction. In addition, in the 2 nd, the beam shape of the condensed region C2 in the YZ plane S including the Y direction and the Z direction is formed such that the laser beam L2 is modulated into an inclined shape inclined in the shift direction at least on the 1 st plane 11a side from the center of the condensed region C2 (the beam shape of the condensed region C2 is the 1 st shape Q1 when viewed from the Z direction). Thus, in the YZ plane S, cracks 13 inclined in the displacement direction are formed. The control of the beam shape in the YZ plane S is as described above with respect to the knowledge of the oblique crack.
Here, the 1 st formation is also to modulate the laser beam L1 into an inclined shape inclined in the shift direction at least on the 1 st surface 11a side of the center of the light-collecting region C1 in the YZ plane S including the Y direction and the Z direction similarly to the 2 nd formation (in this case, the light beam shape of the light-collecting region C1 is the 1 st shape Q1 when viewed from the Z direction). As described above, as shown in fig. 41 b, in the 1 st region A1 of the line a, the crack 13a and the crack 13b are connected, and the crack 13 (oblique crack 13F) extending obliquely is formed throughout the modified regions 12a and 12 b. The oblique crack 13F may reach or not reach the 2 nd surface 11b of the object 11 (may be appropriately set according to the desired processing mode).
The laser beams L1 and L2 may be generated by, for example, displaying a pattern for branching the laser beam L on the spatial light modulator 7 and modulating the laser beam L so as to branch the laser beam L into two. In this case, the 1 st formation and the 2 nd formation are performed simultaneously. However, the lasers L1 and L2 may be different lasers, and in this case, the 1 st formation and the 2 nd formation are performed at the respective time points. The condensed regions C1 and C2 are condensed regions of the laser beams L1 and L2 corresponding to the condensed region C of the laser beam L, respectively.
ON the other hand, in the present embodiment, the control unit 6 switches ON/OFF of the irradiation of the laser light L while rotating the stage 2, so that the light-collecting region C is relatively moved along the 2 nd region A2 in the line a to form the modified region 12, and the formation of the modified region 12 is stopped (2 nd processing) in a region other than the 2 nd region A2 of the line a (1 st region A1), as shown in fig. 42 (a).
As shown in fig. 42 (b), in the 2 ND machining, the rotation direction of the table 2 is controlled by the control of the moving unit 4 of the control unit 6, so that the machining traveling direction ND becomes the forward direction ND1. That is, between the 1 st machining and the 2 ND machining, the forward and reverse directions (forward direction ND1 or reverse direction ND 2) of the machining traveling direction ND are switched. Since the 2 nd process is the process of the 2 nd region A2, the control unit 6 controls the spatial light modulator 7 to form the laser beam L so that the beam shape of the light-condensing region C becomes the 2 nd shape Q2. Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the Z direction from the center of the object 11 toward the 2 nd surface 11b toward the outside (see fig. 31).
The method for forming the oblique crack will be specifically described herein. That is, in the 2 nd processing, as shown in fig. 43 (a), the position of the light collecting region C1 is set at the 1 st Z position Z1 with respect to the Z direction intersecting the 1 st surface 11a, which is the incident surface of the laser beam L1 of the object 11, and the light collecting region C1 is relatively moved along the line a (X direction), whereby the modified region (1 st modified region) 12a and the crack (1 st crack) 13a (1 st crack) extending from the modified region 12a are formed in the object 11. In the 1 st formation, the position of the light condensing region C1 is set at the 1 st Y position Y1 for the Y direction along the 1 st surface 11a and intersecting the X direction.
In addition, in the formation of the 2 nd, the position of the condensed region C2 of the laser light L2 is set to the 2 nd Z position Z2 on the 1 st plane 11a (incidence plane) side than the 1 st Z position Z1 of the condensed region C1 formed in the 1 st direction, and the condensed region C2 is relatively moved along the line a (X direction), thereby forming the modified region 12b (2 nd modified region) and the crack (2 nd crack) 13b (2 nd formation) extending from the modified region 12 b. In this formation 2, the position of the light-condensing region C2 is set to a 2 nd Y position Y2 shifted from the 1 st Y position Y1 of the light-condensing region C1 with respect to the Y direction. In addition, in the 2 nd, the beam shape of the condensed region C2 in the YZ plane S including the Y direction and the Z direction is formed such that the laser beam L2 is modulated into an inclined shape inclined in the shift direction at least on the 1 st plane 11a side from the center of the condensed region C2 (the beam shape of the condensed region C2 is the 2 nd shape Q2 when viewed from the Z direction). Thus, in the YZ plane S, cracks 13 inclined in the displacement direction are formed.
Here, the 1 st formation is also to modulate the laser beam L1 into an oblique shape inclined in the shift direction at least on the 1 st surface 11a side of the center of the light-collecting region C1 in the light-collecting region C1 including the light-collecting region C1 in the Y-direction and the Z-direction in the YZ-plane S similar to the 2 nd formation (in this case, the light-collecting region C1 has the 2 nd shape Q2 when viewed from the Z-direction). As shown in fig. 43 b, in the 2 nd region A2 of the line a, the crack 13a and the crack 13b are connected, and the crack 13 (oblique crack 13F) extending obliquely is formed over the modified regions 12a and 12 b. The crack 13 may reach or not reach the 2 nd surface 11b of the object 11 (may be appropriately set according to the desired processing mode). The modulation pattern for forming the beam shape into the inclined shape is similar to the above.
That is, the modulation pattern here includes a coma aberration pattern for imparting coma aberration to the laser beam L, and is formed at least in the 2 nd, and the control unit 6 controls the magnitude of the coma aberration pattern, thereby performing the 1 st pattern control for making the beam shape of the light-condensing region C2 into an oblique shape. As described above, the coma aberration is imparted to the laser beam L in the same sense as the shift of the spherical aberration correction pattern.
The modulation pattern here includes a spherical aberration correction pattern Ps for correcting the spherical aberration of the laser beam L, and at least in the formation of the 2 nd, the control unit 6 may perform the 2 nd pattern control of shifting the center Pc of the spherical aberration correction pattern Ps in the Y direction with respect to the center of the entrance pupil plane 33a of the condenser lens 33, thereby making the beam shape of the condenser region C2 an oblique shape.
Alternatively, in the formation of the 2 nd, the control unit 6 may perform the 3 rd pattern control of displaying an asymmetric modulation pattern on the spatial light modulator 7 along the axis Ax in the X direction so that the beam shape of the light-condensing region C2 is a tilted shape. The modulation patterns PG1 to PG4 including the grating pattern Ga may be modulation patterns PE (or may include both) including elliptical patterns Es and Ew as modulation patterns asymmetric to the axis Ax.
That is, the modulation pattern here includes elliptical patterns Es and Ew for making the beam shape of the light-collecting region C in the XY plane elliptical with the X direction as a long side, and is formed in the 2 nd, and the control unit 6 may display the modulation pattern PE on the spatial light modulator 7 so that the intensities of the elliptical patterns Es and Ew become asymmetric with respect to the axis Ax along the X direction, thereby performing the 4 th pattern control for making the shape of the light-collecting region C2 oblique.
In addition, in the formation of the second aspect 2, the control unit 6 may display a modulation pattern (for example, the axicon pattern PA described above) for forming the plurality of light-collecting regions C aligned in the shift direction in the YZ plane S on the spatial light modulator 7, and perform the 5 th pattern control for making the beam shape of the light-collecting regions C oblique. The various patterns described above may also be superimposed in any combination. That is, the control unit 6 may be configured to perform any combination of the 1 st to 5 th pattern controls.
The 1 st formation and the 2 nd formation may be performed simultaneously (multi-focus processing), or may be performed sequentially (single-channel processing). That is, the control unit 6 may perform the 1 st formation on, for example, the 1 st region A1 of the line a, and then perform the 2 nd formation. Alternatively, the control unit 6 may display a modulation pattern including a branching pattern for branching the laser light L into the laser light L1, L2 on the spatial light modulator 7, so that, for example, the 1 st region A1 of the line a set in the object 11 is formed simultaneously with the 1 st formation and the 2 nd formation.
Next, in the present embodiment, the 2 nd portion 15B (see fig. 31) of the object 11 is processed. In the portion 15B of fig. 2, oblique cracks, in this case vertical cracks, are not necessarily formed. Then, the processing of the 2 nd portion 15B is performed in the same manner as the trimming processing described above, whereby modified regions 12c and 12d and cracks (vertical cracks) 13c and 13d extending therefrom are formed (see fig. 45). In this case, in the 2 ND portion 15B, it is not necessary to switch the forward and reverse directions of the machining traveling direction ND between the 1 st region A1 and the 2 ND region A2, and other machining different from the 1 st machining and the 2 ND machining can be performed.
However, in the trimming process, in order to suppress the quality degradation of the trimming surface, the beam shape is set to the 1 st shape Q1 (1 st process) at the time of processing the 1 st area A1 and to the 2 ND shape Q2 (2 ND process) at the time of processing the 2 ND area A2, but the longitudinal direction NH of the light collecting region C may be set to the processing traveling direction ND (not inclined to the processing traveling direction ND) at the 2 ND portion 15B, and the light collecting region C may be continuously moved relatively throughout the entire line a to form the modified regions 12C, 12d and the cracks 13C, 13d without performing ON or OFF of the irradiation of the laser light L at the boundary between the 1 st area A1 and the 2 ND area A2. That is, the 2 nd portion 15B may be subjected to a different process from the 1 st process and the 2 nd process. Alternatively, the 1 st Z process and the 2 ND Z process may be performed as different processes without switching the process traveling direction ND in the 2 ND portion 15B, and the 1 st Z process may be performed by relatively moving the light collecting region C along the 1 st region A1 in the line a to form modified regions 12C and 12d along the 1 st region A1 and forming cracks 13C and 13d extending in the Z direction from the modified regions 12C and 12 d; the 2Z-th process relatively moves the light collecting region C along the 2 nd region A2 in the line a, thereby forming modified regions 12C, 12d along the 2 nd region A2, and forming cracks 13C, 13d extending in the Z-direction from the modified regions 12C, 12 d. In this case, in the 1 st and 2 ND processes, the laser light L may be shaped so that the light-collecting region C has a longitudinal direction NH when viewed from the Z direction, and the longitudinal direction NH is inclined toward one of the 1 st and 2 ND crystal orientations K1 and K2, which is larger in angle from the processing direction ND, with respect to the processing direction NDD, in the same manner as in the 1 st and 2 ND processes.
As a result of the above processing, as shown in fig. 44 and 45, the modified region 12 and the crack 13 are formed in the object 11 over the entire line a and over the entire region in the Z direction. In particular, as shown in fig. 45, in the 1 st portion 15A, there are formed: the cracks 13a and 13b are inclined from the 1 st surface 11a of the object 11 toward the 2 nd surface 11b toward the outer edge 110e of the bonding region from a position inside the bonding region between the element layer 110 of the object 11 and the element layer 110R of the object 11R. The cracks 13c and 13d may be discontinuous or broken, or may be continuous. The cracks 13b and 13c may be discontinuous or broken, or may be continuous.
Then, the removal process is performed in the same manner as the trimming process described above. Specifically, the laser beam L is irradiated onto the removal region E without rotating the stage 2, and the irradiation unit 3 is moved in the X direction, so that the condensed region C of the laser beam L is moved relative to the object 11 in the X direction. After rotating the stage 2 by 90 °, the laser beam L is irradiated to the removal region E, and the irradiation unit 3 is moved in the X direction along the X direction, so that the condensed region C of the laser beam L is moved relative to the object 11 in the X direction.
As shown in fig. 46, the modified region 12 and the crack 13 extending from the modified region 12 are formed along a line extending so that the removal region E is equally divided by 4 when viewed from the Z direction. Then, as shown in fig. 47 (a), the removal region E is removed by, for example, a jig or air with the modified region 12 as a boundary. Thus, the semiconductor element 11K is formed from the object 11, and the object 100K including the semiconductor element 11K is obtained.
Next, the semiconductor element 11K is ground from the 1 st surface 11a side. Here, the 2 nd portion 15B is removed and a part of the 1 st portion 15A is removed. The removed part of the 1 st part 15A is a part where the modified regions 12a and 12b are formed. Then, the residual portion of the 1 st portion 15A does not include the modified regions 12a and 12b. When the object 11 is peeled by etching, the polishing can be simplified. As a result of the above, the semiconductor element 11M is formed, and the object 100M including the semiconductor element 11M is obtained.
The laser processing according to the present embodiment described above will be described with reference to the structure of the laser processing apparatus 1. That is, the laser processing apparatus 1 is an apparatus for forming a modified region 12 by irradiating an object 11 with laser light L (laser light L1, L2), and includes at least: the laser irradiation device includes a stage 2 for supporting an object 11, an irradiation unit 3 for irradiating the object 11 supported by the stage 2 with laser light L, moving units 4 and 5 for relatively moving a condensed region C (condensed regions C1 and C2) of the laser light L with respect to the object 11, and a control unit 6 for controlling the moving units 4 and 5 and the irradiation unit 3. The irradiation unit 3 includes a spatial light modulator 7 that shapes the laser light L so that the light-collecting region C has a longitudinal direction NH when viewed from the Z direction.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 1 st processing (the 1 st processing described above), and causes the condensed region C (condensed regions C1 and C2) to move relatively along the 1 st region A1 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) in the object 11 along the 1 st region A1, and forming the oblique crack 13F extending obliquely in the Z direction from the modified region 12 toward the 2 nd surface 11b on the opposite side of the 1 st surface 11a, which is the incident surface of the object 11.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 2 nd machining process (the 2 nd machining process), and relatively moves the condensed regions C (the condensed regions C1 and C2) along the 2 nd region A2 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) on the object 11 along the 2 nd region A2, and forming the oblique crack 13F ( cracks 13a and 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st processing and the 2 nd processing, the control unit 6 controls the spatial light modulator 7 to shape the laser beam L into: the light-collecting region C has a longitudinal direction NH when viewed from the Z direction, and is inclined with respect to the machine direction ND in a direction in which the longitudinal direction NH approaches one of the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 having a larger angle with respect to the machine direction ND, which is the moving direction of the light-collecting region C. In the 1 st machining process and the 2 ND machining process, the control unit 6 controls the moving units 4 and 5 to switch the forward and reverse directions of the machining traveling direction ND between the 1 st machining process and the 2 ND machining process: the direction of inclination of the long side direction NH is the same as the direction in which the oblique crack 13F extends in the machine direction ND when viewed from the Z direction.
Next, the laser processing according to the present embodiment described above will be described in terms of the steps of the laser processing method. That is, the laser processing method of the present embodiment is a method for forming the modified region 12 by irradiating the object 11 with laser light L (laser light L1, L2), and includes A1 st processing step (1 st processing described above) of relatively moving the condensed region C (condensed regions C1, C2) along A1 st region A1 set in a line a of the object 11, thereby forming the modified region 12 (modified regions 12a, 12 b) in the object 11 along the 1 st region A1, and forming oblique cracks 13F ( cracks 13a, 13 b) extending obliquely in the Z direction from the modified region 12 toward a2 nd surface 11b on the opposite side of the 1 st surface 11a, which is an incident surface of the object 11.
The laser processing method of the present embodiment includes A2 nd processing step (the 2 nd processing step) of relatively moving the condensed region C (condensed regions C1, C2) along the 2 nd region A2 in the line a, thereby forming the modified region 12 (modified regions 12a, 12 b) in the object 11 along the 2 nd region A2, and forming the oblique crack 13F ( cracks 13a, 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st and 2 nd processing steps, the laser light L is formed as: the light-collecting region C has a longitudinal direction NH when viewed from the Z direction, and is inclined in a direction approaching the direction of the machine direction ND in which the longitudinal direction NH of the light-collecting region C is larger than the angle between the movement direction of the light-collecting region C, that is, the machine direction ND, from among the 1 st crystal orientation K1 and the 2 ND crystal orientation K2. In the 1 st machining step and the 2 ND machining step, the forward and reverse directions of the machining traveling direction ND are switched between the 1 st machining step and the 2 ND machining step: the direction of inclination of the long side direction NH is the same as the direction in which the oblique crack 13F extends in the machine direction ND when viewed from the Z direction.
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. Here, in the line a in which the condensed region C of the laser light L is relatively moved, the modified region 12 is formed in the object 11 along the 1 st region A1 (1 st processing, 1 st processing step), and the modified region 12 is formed in the object 11 along the 2 nd region A2 in the line a (2 nd processing, 2 nd processing step), the oblique crack 13F extending obliquely with respect to the Z direction (direction intersecting the incident surface) from the modified region 12 toward the 2 nd surface 11b (opposite surface) on the opposite side from the 1 st surface 11a (incident surface) of the object 11 is formed. Then, the forward and reverse directions of the machining direction ND are switched between the 1 st machining process (1 st region A1) and the 2 ND machining process (2 ND region A2), so that the machining direction ND can be set more appropriately according to the crystal structure of the object 11.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 may execute the 1 st processing and the 2 ND processing on the 1 st portion 15A while switching the forward and backward directions of the processing traveling direction ND, and execute another processing (another processing) different from the 1 st processing and the 2 ND processing on the 2 ND portion 15B. In other processing, the control unit 6 may control the irradiation unit 3 and the movement units 4 and 5 so that the forward and backward directions of the processing travel direction ND are the same throughout the entire line a, and the light collecting region C is relatively moved along the line a, thereby forming the modified region 12 and the crack 13 extending in the Z direction from the modified region 12 in the object 11 along the line a. In this case, the time required for acceleration and deceleration of the relative movement of the condensed region C of the laser beam L can be reduced as compared with the case where the 2 ND portion 15B switches the forward and reverse directions of the machine direction ND in the 1 st region A1 and the 2 ND region A2 of the line a.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 may control the spatial light modulator 7 to form the laser beam L into: the light-collecting region C has a longitudinal direction NH as viewed from the Z direction, and the longitudinal direction NH of the light-collecting region C is along the machine direction ND. In this case, in the 2 nd portion 15B of the crack 13 formed along the Z direction, the processing of the control unit 6 is simplified as compared with the case where the laser L is formed so that the inclination of the condensed region C of the laser L is changed between the processing of the 1 st region A1 and the processing of the 2 nd region A2 of the line a.
In the laser processing apparatus 1 according to the present embodiment, the object 11 may include a joint region to be joined to another member (object 11R), and the control unit 6 may form an oblique crack 13F inclined from a position inside the joint region toward an outer edge 11e of the joint region as going from the 1 st surface 11a toward the 2 nd surface 11b in the 1 st processing and the 2 nd processing. In this case, when a part of the object 11 bordered by the oblique crack 13F is removed from the object 11 and the remaining part of the object 11 is left, the object 11 can be prevented from extending outward across the joint region with the other member.
In the laser processing apparatus 1 according to the present embodiment, the object 11 has a crystal structure, and includes: (100) A plane, one (110) plane, the other (110) plane, a1 st crystal orientation K1 orthogonal to the one (110) plane, and a2 nd crystal orientation K2 orthogonal to the other (110) plane, and is supported on the stage 2 so that the (100) plane becomes an incident plane. In the 1 st processing and the 2 nd processing, the control unit 6 controls the spatial light modulator 7 to shape the laser beam L into: the light-collecting region C has a longitudinal direction NH when viewed from the Z direction, and is inclined in a direction approaching the direction of the machine direction ND in which the longitudinal direction NH of the light-collecting region C is larger than the angle between the direction of movement of the light-collecting region C, that is, the machine direction ND, from among the 1 st crystal orientation K1 and the 2 ND crystal orientation K2. Therefore, as shown in the above-mentioned findings, the quality degradation of the trimming surface is suppressed.
In the laser processing apparatus 1 of the present embodiment, in the 1 st processing and the 2 ND processing, the control unit 6 controls the moving units 4 and 5 so as to switch the forward and backward directions of the processing traveling direction ND between the 1 st processing and the 2 ND processing: the direction of inclination of the long side direction NH is the same as the direction in which the oblique crack 13F extends in the machine direction ND when viewed from the Z direction. Therefore, in both the 1 st region A1 and the 2 ND region A2, the longitudinal direction NH of the light collecting region C is inclined toward the machine direction ND and the oblique crack 13F extends on the same side. Therefore, as shown in the above-described findings, the relationship between the direction of the longitudinal direction NH of the light collecting region C and the oblique direction of the oblique crack 13F can be a combination that can obtain relatively good quality, and the quality degradation is suppressed. As described above, in this case, the oblique crack 13F can be formed while suppressing the quality degradation of the trimming surface of the object 11.
In the laser processing apparatus 1 according to the present embodiment, the object 11 may include the 1 st portion 15A and the 2 nd portion 15B arranged in this order from the 2 nd surface 11B side along the Z direction. The control unit 6 performs the 1 st processing and the 2 ND processing on the 1 st portion 15A while switching the forward and backward directions of the processing traveling direction ND, performs the 1 st processing and the 2 ND processing as different processing without switching the processing traveling direction ND on the 2 ND portion 15B, controls the irradiation unit 3 and the moving units 4 and 5 so as to relatively move the condensed region C along the 1 st region A1 in the line a, forms the modified region 12 in the object 11 along the 1 st region A1, and forms the crack 13 extending in the Z direction from the modified region 12 (the 1 st processing); in this 2Z processing (2 nd processing described above), the irradiation unit 3 and the moving units 4 and 5 are controlled to relatively move the light collecting region C along the 2 nd region A2 in the line a, thereby forming the modified region 12 in the object 11 along the 2 nd region A2 and forming the crack 13 extending in the Z direction from the modified region 12. In this case, also in the 2 ND portion 15B, the time required for acceleration and deceleration of the relative movement of the condensed region C of the laser beam L can be reduced as compared with the case where the longitudinal direction NH of the condensed region C is set in the 1 st region A1 and the 2 ND region A2 according to the machining traveling direction ND and the forward and reverse directions of the machining traveling direction ND are switched in the 1 st region A1 and the 2 ND region A2.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 can execute the 1 st processing and the 2 nd processing, and the 1 st processing (the 1 st processing described above) and the 2 nd processing can be executed, wherein the position of the light-collecting region C1 is set to the 1 st Z position Z1 with respect to the Z direction, and the light-collecting region C1 is relatively moved along the line a, so that the modified region 12a and the crack 13a extending from the modified region 12a are formed in the object 11; in the 2 nd formation process (the 2 nd formation described above), the position of the light-collecting region C2 is set to a 2 nd Z position Z2 on the 1 st surface 11a side from the 1 st Z position Z1 in the Z direction, and the light-collecting region C2 is relatively moved along the line a, thereby forming the modified region 12b and the crack 13b extending from the modified region 12 b.
In the 1 st forming process, the control unit 6 may set the position of the light-collecting region C1 in the Y direction intersecting the machine direction ND and the Z direction as the 1 st Y position Y1, and in the 2 ND forming process, the control unit 6 may set the position of the light-collecting region C2 in the Y direction as the 2 ND Y position Y2 shifted from the 1 st Y position Y1, and shape the laser beam L2 by control of the spatial light modulator 7 so as to: the shape of the light-collecting region C2 in the YZ plane S including the Y direction and the Z direction is formed in an inclined shape inclined in the shift direction at least in the 1 st plane 11a side with respect to the center of the light-collecting region C2, so that an oblique crack 13b is formed in the YZ plane S in the shift direction. Thus, oblique cracks inclined to the Z direction can be formed appropriately.
In the laser processing apparatus 1 according to the present embodiment, the irradiation unit 3 may include a condensing lens 33 for condensing the laser beam L from the spatial light modulator 7 toward the object 11, and the control unit 6 may form the laser beam L by modulating the laser beam L to a shape in which the condensing region C is inclined by controlling the modulation pattern displayed on the spatial light modulator 7 in the 2 nd formation process. In this case, the laser light L can be easily shaped using the spatial light modulator 7.
In this case, in the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a coma aberration pattern for imparting coma aberration to the laser beam L, and the control unit 6 may control the size of the coma aberration pattern in the 2 nd formation process, thereby performing the 1 st pattern control for making the shape of the light-collecting region C be a tilted shape. According to the findings of the present inventors, the shape of the light-collecting region C in the YZ plane S is formed in an arc shape. That is, in this case, the shape of the light collecting region C is inclined in the 1 st plane 11a (incidence plane) side shift direction than the center Ca of the light collecting region C, and is inclined in the opposite side direction to the incidence plane than the center Ca of the light collecting region C. Even in this case, the oblique crack 13F may be formed so as to be inclined in the displacement direction.
In the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a spherical aberration correction pattern for correcting the spherical aberration of the laser beam L, and the control unit 6 may perform the 2 nd pattern control of shifting the center of the spherical aberration correction pattern Ps in the Y direction with respect to the center of the entrance pupil plane 33a of the condenser lens 33 in the 2 nd formation process, thereby making the shape of the condenser region C an oblique shape. According to the findings of the present inventors, in this case as well, as in the case of using the coma aberration pattern, the shape of the light collecting region C can be formed in an arc shape in the YZ plane S, and oblique cracks 13F inclined in the shift direction can be formed.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 may perform the 3 rd pattern control of displaying an asymmetric modulation pattern on the spatial light modulator 7 along the axis in the processing traveling direction ND in the 2 ND formation process so that the shape of the light collecting region C is a tilted shape. According to the findings of the present inventors, in this case, the entirety of the shape of the light condensing region C in the YZ plane S can be inclined in the shift direction. Even in this case, the oblique crack 13F may be formed so as to be inclined in the displacement direction.
In the laser processing apparatus 1 of the present embodiment, the modulation pattern may include an elliptical pattern in which the shape of the light-collecting region C in the XY plane including the X direction and the Y direction intersecting the Y direction and the Z direction is an elliptical shape having the long side in the X direction, and the control unit 6 may perform the 4 th pattern control for making the beam shape an inclined shape by displaying the modulation pattern on the spatial light modulator 7 so that the intensity of the elliptical pattern becomes asymmetric with respect to the axis along the X direction in the 2 nd formation process. According to the findings of the present inventors, in this case, too, the shape of the light collecting region C may be formed in an arc shape in the YZ plane S, and an oblique crack 13F inclined in the displacement direction may be formed.
In the laser processing apparatus 1 according to the present embodiment, in the 2 nd formation process, the control unit 6 may display a modulation pattern for forming the converging points CI of the plurality of lasers L arranged in the shift direction in the YZ plane S on the spatial light modulator 7, thereby performing 5 th pattern control for making the shape of the converging region C including the plurality of converging points CI an oblique shape. According to the findings of the present inventors, in this case, oblique cracks 13F inclined in the displacement direction may be formed.
[ embodiment 2 of laser processing ]
Next, another embodiment of the laser processing for forming oblique cracks during the trimming processing will be described. Fig. 48 is a diagram showing an object to be laser-processed according to an embodiment. As shown in fig. 48, the laser-machined object of the present embodiment is an object 11 that is bonded to an object 11R to form an object 100, as in embodiment 1. However, in this embodiment, the angle ranges of the 1 st and 2 nd regions A1 and A2 of the line a are different from those of embodiment 1.
In embodiment 1, the boundary between the 1 st area A1 and the 2 nd area A2 is set at a point of 45 ° or-45 ° where the quality degradation of the trimming surface is likely to occur, as an example. This is because, in embodiment 1, it is known that even at the points of 45 ° and-45 ° where the quality degradation is likely to occur, the quality degradation can be suppressed by adjusting the forward and reverse directions of the machining traveling direction ND and making the direction of the long-side direction NH of the light collecting region C inclined to the machining traveling direction ND and the direction in which the oblique crack 13F extends the same at the time of machining at the points of 45 ° and-45 °.
On the other hand, as shown in the table of fig. 38, for example, when the machining traveling direction ND at the time of machining of the 1 st region A1 and the 2 ND region A2 is made to be the forward direction ND1 (refer to the table of 1 st and 3 rd from the top), a point of-45 ° can be known, and when the beam shape of the light-condensing region C is made to be the 1 st shape Q1 (refer to the table of 3 rd from the top), although the quality is reduced, a good quality is obtained when the beam shape is made to be the 2 ND shape Q2 (refer to the table of 1 st from the top), and a good quality is still obtained at a point of-50 °.
Even if the machining traveling directions ND at the time of machining the 1 st region A1 and the 2 ND region A2 are unified to the forward direction ND1, the beam shape of the light-collecting region C is set to the 2 ND shape Q2 at the time of machining in the angle range from about 0 ° to about-50 °, and the beam shape of the light-collecting region C is set to the 1 st shape Q1 at the time of machining in the angle range from about-50 ° to about-90 °, so that good machining quality can be obtained in all the angle ranges. In practice, it can be seen from the table of fig. 49 that by using both the condition IR7 and the condition IR8, good processing quality is obtained in all the angle ranges.
For example, when the machining traveling direction ND at the time of machining in each of the 1 st region A1 and the 2 ND region A2 is the reverse direction ND2 (see the tables 2 and 4 from the top), a point of-45 ° can be known, and in contrast to the case of the forward direction D1, when the beam shape in the light-condensing region C is set to the 2 ND shape Q2 (see the table 2 from the top), although the quality is reduced, when the beam shape is set to the 1 st shape Q1 (see the table 4 from the top), a good quality is obtained, and a good quality is still obtained at a point of-40 °.
Even if the machining traveling direction ND at the time of machining the 1 st region A1 and the 2 ND region A2 is made uniform in the reverse direction ND2, the beam shape of the light-collecting region C is made to be the 2 ND shape Q2 at the time of machining in the angle range from about 0 ° to about-40 °, and the beam shape of the light-collecting region C is made to be the 1 st shape Q1 at the time of machining in the angle range from about-40 ° to about-90 °, so that good machining quality can be obtained in all the angle ranges. In practice, it can be seen from the table of fig. 50 that by using both the condition IR9 and the condition IR10, good processing quality is obtained in all the angle ranges.
That is, on the premise that the longitudinal direction NH of the light collecting region C is inclined with respect to the direction of the processing direction ND approaching the direction of the greater angle between the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 and the processing direction ND, when the processing of the 1 st region A1 (the 1 st processing) and the processing of the 2 ND region A2 (the 2 ND processing) are the same in the forward and backward directions of the processing direction, the boundaries of the 1 st region A1 and the 2 ND region A2 are set so that the direction of the inclination of the longitudinal direction NH includes a 45 ° (the point of-45 ° (the example) with respect to the processing direction ND is the same as the side on which the oblique crack 13F extends, and a good processing quality can be obtained in all the angle ranges.
The laser processing according to the present embodiment is performed based on the above findings. That is, in the laser processing of the present embodiment, as shown in fig. 48, the boundary Ks between the 1 st area A1 and the 2 ND area A2 is a point (the point of-45 ° in the above example) set such that the inclination of the longitudinal direction NH is oriented at 45 ° to the same side as the side where the oblique crack 13F extends in the processing direction ND. In the illustrated example, the boundary Ks is set so that the machine direction ND becomes the forward direction ND1 and the 2 ND region A2 includes a 45 ° point.
In particular, in this case, the 1 st region A1 is reduced by about 5 ° to form an arc of about 40 ° from about 0 ° to about 40 ° and the 2 nd region A2 is enlarged by about 5 ° to form an arc of about 50 ° from about 40 ° to about 90 ° compared with the 1 st embodiment, so that the 2 nd region A2 is longer than the 1 st region A1 by a portion of about 10 °. The processing of each of the 1 st and 2 ND areas A1 and A2 is performed in the same manner as the 1 st and 2 ND processing (even the 1 st and 2 ND processing) except that the processing traveling direction ND is unified to the forward direction ND1 (or the reverse direction ND 2).
The laser processing according to the present embodiment described above will be described with reference to the structure of the laser processing apparatus 1. That is, the laser processing apparatus 1 is an apparatus for forming a modified region 12 by irradiating an object 11 with laser light L (laser light L1, L2), and includes at least: the laser beam irradiation apparatus includes a stage 2 for supporting an object 11, an irradiation unit 3 for irradiating the object 11 supported by the stage 2 with a laser beam L, moving units 4 and 5 for relatively moving a condensed region C (condensed regions C1 and C2) of the laser beam L with respect to the object 11, and a control unit 6 for controlling the moving units 4 and 5 and the irradiation unit 3. The irradiation unit 3 includes a spatial light modulator 7 that shapes the laser light L so that the light-collecting region C has a longitudinal direction NH when viewed from the Z direction.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 1 st processing (the 1 st processing), and causes the condensed regions C (the condensed regions C1 and C2) to move relatively along the 1 st region A1 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) in the object 11 along the 1 st region A1, and forming oblique cracks 13F ( cracks 13a and 13 b) extending obliquely in the Z direction from the modified region 12 toward the 2 nd surface 11b on the opposite side of the 1 st surface 11a, which is the incident surface of the object 11.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 2 nd machining process (the 2 nd machining process), and relatively moves the condensed regions C (the condensed regions C1 and C2) along the 2 nd region A2 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) on the object 11 along the 2 nd region A2, and forming the oblique crack 13F ( cracks 13a and 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st processing and the 2 nd processing, the control unit 6 controls the spatial light modulator 7 to shape the laser beam L into: the longitudinal direction NH of the light collecting region C is inclined in the direction approaching the larger angle between the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 and the direction of movement of the light collecting region C, that is, the machining direction ND, and the machining direction ND of the 1 st machining process and the machining direction ND of the 2 ND machining process are the same in the forward and reverse directions.
When the point at which the 2 ND crystal orientation K2 is perpendicular to the line a is set to 0 °, the point at which the 1 st crystal orientation K1 is perpendicular to the line a is set to 90 °, and the point at the middle of the line a between 0 ° and 90 ° is set to 45 °, the boundary Ks between the 1 st region A1 and the 2 ND region A2 is set such that the direction of inclination of the long-side direction NH as viewed from the Z direction is 45 ° to one of the sides on which the oblique crack 13F extends with respect to the machine direction ND.
Next, the laser processing according to the present embodiment described above will be described in terms of the steps of the laser processing method. That is, the laser processing method of the present embodiment is a method for forming the modified region 12 by irradiating the object 11 with laser light L (laser light L1, L2), and includes A1 st processing step (1 st processing described above) of relatively moving the condensed region C (condensed regions C1, C2) along A1 st region A1 set in a line a of the object 11, thereby forming the modified region 12 (modified regions 12a, 12 b) in the object 11 along the 1 st region A1, and forming oblique cracks 13F ( cracks 13a, 13 b) extending obliquely in the Z direction from the modified region 12 toward a2 nd surface 11b on the opposite side of the 1 st surface 11a, which is an incident surface of the object 11.
The laser processing method of the present embodiment includes A2 nd processing step (the 2 nd processing step) of relatively moving the condensed region C (condensed regions C1, C2) along the 2 nd region A2 in the line a, thereby forming the modified region 12 (modified regions 12a, 12 b) in the object 11 along the 2 nd region A2, and forming the oblique crack 13F ( cracks 13a, 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st and 2 nd processing steps, the laser light L is formed as: the light-collecting region C has a longitudinal direction NH when viewed from the Z direction, and the longitudinal direction NH of the light-collecting region C is inclined with respect to the machine direction ND toward one of the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 that is larger than the angle between the machine direction ND and the movement direction of the light-collecting region C, and the forward and reverse directions of the machine direction ND in the 1 st machining step and the 2 ND machining step are the same.
When the point at which the 2 ND crystal orientation K2 is perpendicular to the line a is set to 0 °, the point at which the 1 st crystal orientation K1 is perpendicular to the line a is set to 90 °, and the point at the middle of the line a between 0 ° and 90 ° is set to 45 °, the boundary Ks between the 1 st region A1 and the 2 ND region A2 is set such that the direction of inclination of the long-side direction NH as viewed from the Z direction is 45 ° to one of the sides on which the oblique crack 13F extends with respect to the machine direction ND.
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, and includes: (100) A plane, one (110) plane, the other (110) plane, a1 st crystal orientation K1 orthogonal to the one (110) plane, and a2 nd crystal orientation K2 orthogonal to the other (110) plane. Here, in the line a in which the condensed region C of the laser light L is relatively moved, the laser light L is formed as follows in each of the case where the modified region 12 is formed in the object 11 along the 1 st region A1 (1 st processing, 1 st processing step) and the case where the modified region 12 is formed in the object 11 along the 2 nd region A2 (2 nd processing, 2 nd processing step) of the line a: the longitudinal direction NH of the light collecting region C is inclined with respect to the machine direction ND in a direction approaching the larger angle between the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 and the machine direction ND. Therefore, as shown in the above-mentioned findings, the quality degradation of the trimming surface is suppressed.
On the other hand, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the 1 st processing step and the 2 nd processing step (the 1 st processing step and the 2 nd processing step are also the same (hereinafter the same)), and the oblique crack 13F extending obliquely to the Z direction (the direction intersecting the incident surface) from the modified region 12 toward the 2 nd surface 11b (the opposite surface) on the opposite side from the 1 st surface 11a (the incident surface) of the object 11 is formed. Then, it is necessary to consider the relationship between the extending direction of the oblique crack 13F and the direction of the longitudinal direction NH of the light collecting region C. In particular, in the case of machining at the 45 ° point, the quality of the trimming surface tends to be lowered when the direction of the longitudinal direction NH of the light collecting region C and the direction of inclination of the oblique crack 13F are opposite to each other with respect to the machining traveling direction ND.
In contrast, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the boundary Ks between the 1 st region A1 and the 2 ND region A2 is set to a point where the direction of inclination of the longitudinal direction NH in the 1 st region A1 and the 2 ND region A2 is 45 ° to the processing direction ND on the same side as the side on which the oblique crack 13F extends. In other words, in the 1 st region A1 and the 2 ND region A2, the point of the line a at 45 ° is not reached in the region where the machining is performed in a state where the longitudinal direction NH of the light collecting region C and the oblique direction of the oblique crack 13F are opposite to each other with respect to the machining traveling direction ND. Thus, quality degradation can be suppressed. As described above, according to the laser processing apparatus 1 and the laser processing method of the present embodiment, the oblique crack 13F can be formed while suppressing the quality degradation of the trimming surface of the object 11.
In the laser processing apparatus 1 and the laser processing method according to the present embodiment, the processing direction ND of the 1 st processing and the processing direction ND of the 2 ND processing are identical in both the forward and backward directions. Thus, the time required for acceleration and deceleration of the relative movement of the condensed region C of the laser light L can be reduced as compared with the case where the forward and reverse directions of the processing travel direction ND are switched between the 1 st processing and the 2 ND processing.
In the laser processing apparatus 1 according to the present embodiment, the 1 st region A1 and the 2 ND region A2 may be longer than the other region in which the inclination direction of the long-side direction NH is the same as the side on which the oblique crack 13F extends with respect to the processing traveling direction ND, as viewed from the Z direction. As described above, the lengths of the 1 st area A1 and the 2 nd area A2 may be set individually.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 may execute the 1 st processing and the 2 ND processing on the 1 st portion 15A while making the forward and backward directions of the processing travel direction ND identical, and execute another processing (another processing) different from the 1 st processing and the 2 ND processing on the 2 ND portion 15B. In other processing, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 so that the forward and backward directions of the processing traveling direction ND are the same throughout the entire line a and the light collecting region C is relatively moved, thereby forming the modified region 12 and the crack 13 extending in the Z direction from the modified region 12 in the object 11 along the line a. In this case, the time required for acceleration and deceleration of the relative movement of the condensed region C of the laser beam L can be reduced as compared with the case where the 2 ND portion 15B switches the forward and reverse directions of the machine direction ND in the 1 st region A1 and the 2 ND region A2 of the line a.
In the laser processing apparatus 1 according to the present embodiment, the spatial light modulator 7 may be controlled to shape the laser beam L in other processing steps: the light-collecting region C has a longitudinal direction NH as viewed from the Z direction, and the longitudinal direction NH of the light-collecting region C is along the machine direction ND. In this case, in the 2 nd portion 15B where the crack 13 is formed along the Z direction, the processing of the control unit 6 is simplified as compared with the case where the laser L is formed so that the inclination of the condensed region C of the laser L is changed between the processing of the 1 st region A1 and the processing of the 2 nd region A2 of the line a.
In the laser processing apparatus 1 of the present embodiment, the 1 st Z processing (the 1 st Z processing described above) and the 2 ND Z processing are performed as different processing processes without switching the processing traveling direction ND of the 2 ND portion 15B, and the irradiation unit 3 and the moving units 4 and 5 may be controlled so that the condensed region C is relatively moved along the 1 st region A1 in the line a, thereby forming the modified region 12 in the object 11 along the 1 st region A1, and forming the crack 13 extending in the Z direction from the modified region 12; in this 2Z processing (2 nd processing described above), the irradiation unit 3 and the moving units 4 and 5 are controlled to relatively move the light collecting region C along the 2 nd region A2 in the line a, thereby forming the modified region 12 in the object 11 along the 2 nd region A2 and forming the crack 13 extending in the Z direction from the modified region 12. In this case, also in the 2 ND portion 15B, the time required for acceleration and deceleration of the relative movement of the condensed region C of the laser beam L can be reduced as compared with the case where the longitudinal direction NH of the condensed region C is set in the 1 st region A1 and the 2 ND region A2 according to the machining traveling direction ND and the forward and reverse directions of the machining traveling direction ND are switched in the 1 st region A1 and the 2 ND region A2.
In the laser processing apparatus 1 according to the present embodiment, the object 11 may include a joint region to be joined to another member (object 11R), and the control unit 6 may form an oblique crack 13F inclined from a position inside the joint region toward an outer edge 11e of the joint region from the 1 st processing and the 2 nd processing toward the 2 nd surface 11b in the 1 st processing and the 2 nd processing. In this case, when a part of the object 11 bordered by the oblique crack 13F is removed from the object 11 and the remaining part of the object 11 is left, the object 11 can be prevented from extending outward across the joint region with the other member.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 can execute the 1 st processing and the 2 nd processing, and the 1 st processing (the 1 st processing described above) and the 2 nd processing can be executed, wherein the position of the light-collecting region C1 is set to the 1 st Z position Z1 with respect to the Z direction, and the light-collecting region C1 is relatively moved along the line a, so that the modified region 12a and the crack 13a extending from the modified region 12a are formed in the object 11; in the 2 nd formation process (the 2 nd formation described above), the position of the light-collecting region C2 is set to a 2 nd Z position Z2 on the 1 st surface 11a side from the 1 st Z position Z1 in the Z direction, and the light-collecting region C2 is relatively moved along the line a, thereby forming the modified region 12b and the crack 13b extending from the modified region 12 b.
In the 1 st forming process, the control unit 6 may set the position of the light-collecting region C1 in the Y direction intersecting the machine direction ND and the Z direction as the 1 st Y position Y1, and in the 2 ND forming process, the control unit 6 may set the position of the light-collecting region C2 in the Y direction as the 2 ND Y position Y2 shifted from the 1 st Y position Y1, and shape the laser beam L2 by control of the spatial light modulator 7 so as to: the shape of the light-collecting region C2 in the YZ plane S including the Y direction and the Z direction is formed in an inclined shape inclined in the shift direction at least in the 1 st plane 11a side with respect to the center of the light-collecting region C2, so that an oblique crack 13F inclined in the shift direction is formed in the YZ plane S. Thus, oblique cracks inclined to the Z direction can be formed appropriately.
In the laser processing apparatus 1 according to the present embodiment, the irradiation unit 3 may include a condensing lens 33 for condensing the laser beam L from the spatial light modulator 7 toward the object 11, and the control unit 6 may form the laser beam L by modulating the laser beam L to a shape in which the condensing region C is inclined by controlling the modulation pattern displayed on the spatial light modulator 7 in the 2 nd formation process. In this case, the laser light L can be easily shaped using the spatial light modulator 7.
In this case, in the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a coma aberration pattern for imparting coma aberration to the laser beam L, and the control unit 6 may control the size of the coma aberration pattern in the 2 nd formation process, thereby performing the 1 st pattern control for making the shape of the light-collecting region C be a tilted shape. According to the findings of the present inventors, the shape of the light-collecting region C in the YZ plane S is formed in an arc shape. That is, in this case, the shape of the light collecting region C is inclined in the 1 st plane 11a (incidence plane) side shift direction than the center Ca of the light collecting region C, and is inclined in the opposite side direction to the incidence plane than the center Ca of the light collecting region C. Even in this case, the oblique crack 13F may be formed so as to be inclined in the displacement direction.
In the laser processing apparatus 1 of the present embodiment, the modulation pattern may include a spherical aberration correction pattern for correcting the spherical aberration of the laser beam L, and the control unit 6 may perform the 2 nd pattern control of shifting the center of the spherical aberration correction pattern Ps in the Y direction with respect to the center of the entrance pupil plane 33a of the condenser lens 33 in the 2 nd formation process, thereby making the shape of the condenser region C an oblique shape. According to the findings of the present inventors, in this case as well, as in the case of using the coma aberration pattern, the shape of the light collecting region C can be formed in an arc shape in the YZ plane S, and oblique cracks 13F inclined in the shift direction can be formed.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 may perform the 3 rd pattern control of displaying an asymmetric modulation pattern on the spatial light modulator 7 along the axis in the processing traveling direction ND in the 2 ND formation process so that the shape of the light collecting region C is a tilted shape. According to the findings of the present inventors, in this case, the entirety of the shape of the light condensing region C in the YZ plane S can be inclined in the shift direction. Even in this case, the oblique crack 13F may be formed so as to be inclined in the displacement direction.
In the laser processing apparatus 1 of the present embodiment, the modulation pattern may include an elliptical pattern in which the shape of the light-collecting region C in the XY plane including the X direction and the Y direction intersecting the Y direction and the Z direction is an elliptical shape having the long side in the X direction, and the control unit 6 may perform the 4 th pattern control for making the beam shape an inclined shape by displaying the modulation pattern on the spatial light modulator 7 so that the intensity of the elliptical pattern becomes asymmetric with respect to the axis along the X direction in the 2 nd formation process. According to the findings of the present inventors, in this case, too, the shape of the light collecting region C may be formed in an arc shape in the YZ plane S, and an oblique crack 13F inclined in the displacement direction may be formed.
In the laser processing apparatus 1 according to the present embodiment, in the 2 nd formation process, the control unit 6 may display a modulation pattern for forming the converging points CI of the plurality of lasers L arranged in the shift direction in the YZ plane S on the spatial light modulator 7, thereby performing 5 th pattern control for making the shape of the converging region C including the plurality of converging points CI an oblique shape. According to the findings of the present inventors, in this case, oblique cracks 13F inclined in the displacement direction may be formed.
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-described aspect, and may be modified.
For example, in the above example, the object 100 (bonded wafer) is formed by bonding the object 11 and the object 11R, but the object of laser processing is not limited to such bonded wafer, and may be an object such as a single wafer.
In the example shown in fig. 45, the two modified regions 12a and 12b are formed using the two light collecting regions C1 and C2 for the 1 st portion 15A. In this case, at least the beam shape in the YZ plane S of the light collecting region C2 on the 1 st plane 11a side is controlled at the time of formation of the oblique crack 13F. However, in the case of forming the plurality of groups of modified regions 12a and 12b in the 1 st portion 15A, when forming the modified regions 12a and 12b closest to the 2 nd surface 11b (the object 11R side), at least the beam shape in the YZ plane S of the light collecting region C2 closest to the 1 st surface 11a may be controlled.
In the above embodiment, the vertical crack is formed in the 2 nd portion 15B of the object 11. However, oblique cracks may be formed in the 2 nd portion 15B of the object 11 in the same manner as in the 1 st portion 15A.
In the laser processing of embodiment 1, it is described that the processing of the 1 st area A1, i.e., the 1 st processing, and the processing of the 2 nd area A2, i.e., the 2 nd processing, in the line a are set ON the GUI so as to be switched at 45 ° intervals such as 0 °, 45 °, 90 °, and the actual ON and OFF of the laser light are also performed at the same angle. However, in an actual device, delay due to ON and OFF of the laser may be slower than setting by about several hundred msec. That is, the laser is not limited to the case where the laser is strictly turned ON or OFF at the boundary between the 1 st area A1 and the 2 nd area A2.
For the above reasons, the control unit 6 may have correction parameters for correcting the delay time of the ON and OFF of the laser beam in advance so as to reduce the amount of positional error in the formation of the modified region 12. In this case, the error in the formation position of the modified region 12 can be suppressed to 1mm or less. For example, in the case where the object 11 is a 12 inch wafer, the circumference is about 942mm, and about 2.617mm for every 1 ° and thus the error in this case can be converged within 1 °.
As shown in the results of fig. 38, a machining quality margin of about ±5° was confirmed at the switching point between the 1 st region A1 and the 2 nd region A2. Therefore, as long as the setting of the switching point is within the mass margin of +5°, 45 ° ± 5 °, 90 ° ± 5 °, or may be intentionally staggered.
In the above embodiment, for example, the modified region 12 formed in a ring shape when viewed from the Z direction is formed by turning ON and OFF the laser, and in the strict sense, the modified region 12 (for example, about several hundreds μm) is partially overlapped at the ON and OFF positions, or the modified region 12 may be formed in a region (for example, about several hundreds μm) where a part is not formed. In order to prevent deterioration of quality due to such influence, the formation of oblique cracks and the processing having the effects of the 1 st processing and the 2 nd processing may be performed in a plurality of stages by a plurality of stages of processing.
In addition, in actual processing, since a running-up distance is required until the speed of the relative movement of the light-collecting region C becomes constant, switching between the forward direction ND1 and the reverse direction ND2 includes running-up. The laser is turned OFF at the time of running, and is turned ON at the switching point after the constant speed is reached. Running up is several revolutions depending on the performance of the device. The autofocus may be adjusted so that the focus follows from the run-up time and no overshoot occurs when the modified region is formed.
In embodiment 2, the switching accuracy is common to the above examples, but as shown in the table of fig. 49, the switching points such as the 45 ° point and the 135 ° point are not switched at least at the-45 ° point and are switched around the-50 ° point (as shown in the table of fig. 50, the switching is performed around the-40 ° point). In this case, the allowable range of the shift is about ±2° as an example, but the beam shape (further improvement of the ellipticity) may be increased to about ±4°, for example. On the other hand, although the switching points of 0 ° and 90 ° are not necessarily shifted, the range of the blending quality may be shifted by, for example, about ±4°.
[ embodiment 3 of laser processing ]
Next, another embodiment of the laser processing for forming oblique cracks during the trimming processing will be described. First, in the case of performing the laser processing according to embodiment 1 and embodiment 2, it is apparent that the novel problems are related. That is, the present inventors have found that even when the direction of the longitudinal direction NH of the beam shape is set based on the machine direction ND and the crystal structure as described above, there is room for further suppressing the quality degradation of the trimming surface in a specific region of the line a in which the light collecting region C is relatively moved.
That is, the object 11 has a crystal structure having a (100) plane, one (110) plane, another (110) plane, a1 st crystal orientation K1 orthogonal to the one (110) plane, and a2 nd crystal orientation K2 orthogonal to the other (110) plane, wherein a point where the line a is orthogonal to the 2 nd crystal orientation K2 is 0 °, a point where the line a is orthogonal to the 1 st crystal orientation K1 is 90 °, and a point between 0 ° and 90 ° of the line a is 45 °.
In this case, for example, as shown in fig. 38, 49, and 50, in the region around 45 ° of the line a, a good machining result (evaluation "B") can be obtained by adjusting the shape of the light-collecting region C or the forward and backward directions of the machining traveling direction ND, but it is understood that there is room for improvement in the better machining result (evaluation "a").
In this regard, the present inventors have found the following: the region including 45 ° of the line a is set independently of the 1 st region A1 and the 2 ND region A2, and in this region, if the direction of the longitudinal direction NH of the beam shape is made to be along the machine direction ND, the quality of the trimming surface becomes better. In this regard, it is 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 above-described embodiments 1 and 2, but the setting of the line a is different. That is, in the present embodiment, the line a includes: a1 st region A1 including 0 °, A2 nd region A2 including 90 °, and A3 rd region A3 in a circular arc shape including 45 ° which is a region between the 1 st region A1 and the 2 nd region A2.
Here, as an example, the 1 st region A1 is 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 °, and the 2 nd region A2 is 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 °. Then, the 3 rd region A3 is 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, the 3 rd region A3 is interposed between the 1 st region A1 and the 2 nd region A2, and has a width of 10 ° with a 90 ° interval.
In addition, as in the case described above, the above-described angle ranges of the 1 st region A1, the 2 nd region A2, and the 3 rd region A3 can be arbitrarily changed depending on where the point is set to 0 °. For example, when the point at which the 1 st crystal orientation K1 is perpendicular to the line a is set to 0 ° (when the above-mentioned point at 90 ° is set to 0 °), the 1 st region A1, the 2 nd region A2, and the 3 rd region A3 are angular ranges rotated by 90 ° from the above-mentioned angular ranges. In the case where the 0 ° point is set as described above, the point rotated 45 ° clockwise from the 0 ° point, that is, the 315 ° point may be changed to the-45 ° point. The point of the boundary between the 1 st region A1, the 2 nd region A2, and the 3 rd region A3 may be included in any one of the 1 st region A1, the 2 nd region A2, and the 3 rd region A3, or may be included in two adjacent ones thereof.
The 1 st and 2 nd processes similar to those of the 1 st and 2 nd embodiments described above are performed on the 1 st and 2 nd regions A1 and A2 nd region A2, and the 3 rd process different from those is performed on the 3 rd region A3. As shown in fig. 52, in the 3 rd processing, the trimming processing is performed while forming oblique cracks as in the 1 st processing and the 2 ND processing, but at this time, the laser light L is formed so that the longitudinal direction NH of the laser light L converging region C becomes the 3 rd shape Q3 along the processing traveling direction ND.
Accordingly, as shown in fig. 53, a more favorable machining result (evaluation "a") was obtained in the 3 rd region A3 from-40 ° to-50 ° regardless of the forward and backward directions of the machining traveling direction ND. Fig. 53 is a table showing actual machining results (quality of the trimming surface) in a state where the longitudinal direction of the laser beam converging region is along the machining traveling direction. In the present embodiment, laser processing is performed based on the above findings. Next, laser processing according to embodiment 3 will be described.
In embodiment 3, first, the 1 st portion 15A (see fig. 31) of the object 11 is processed. That is, the 1 st process similar to that of embodiment 1 is performed. More specifically, as shown in fig. 54, first, the control unit 6 switches ON/OFF of the irradiation of the laser light L while rotating the stage 2, thereby relatively moving the light-collecting region C along the 1 st region A1 of the line a to form the modified region 12, and the formation of the modified region 12 is stopped (1 st process) in regions other than the 1 st region A1 of the line a (the 2 nd regions A2 and 3 rd regions A3).
In the 1 st machining, the rotation direction of the table 2 is controlled by the control of the moving unit 4 of the control unit 6 so that the machining traveling direction ND becomes the reverse direction ND2. Since the 1 st process is the process of the 1 st region A1, the control unit 6 controls the spatial light modulator 7 to form the laser beam L so that the beam shape of the light-condensing region C becomes the 1 st shape Q1 (see fig. 40 (b)). Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the direction from the center of the object 11 to the outside in the Z direction toward the 2 nd surface 11b (see fig. 31). The method for forming oblique cracks is the same as in embodiment 1.
Next, in embodiment 3, by switching ON/OFF of the irradiation of the laser light L by the control unit 6 while rotating the stage 2, as shown in fig. 54, the light-collecting region C is relatively moved along the 2 nd region A2 in the line a to form the modified region 12, and the formation of the modified region 12 is stopped (2 nd processing) in the regions (1 st region A1 and 3 rd region A3) other than the 2 nd region A2 of the line a.
In the 2 ND process, the rotation direction of the table 2 is controlled by the control of the moving unit 4 of the control unit 6, so that the machine direction ND becomes the forward direction ND1. That is, between the 1 st machining and the 2 ND machining, the forward and reverse directions (forward direction ND1 or reverse direction ND 2) of the machining traveling direction ND are switched. Since the 2 nd process is the process of the 2 nd region A2, the control unit 6 performs the formation of the laser beam L by the spatial light modulator 7, and the beam shape of the light-condensing region C is set to the 2 nd shape Q2 (see fig. 42 (b)). Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the Z direction from the center of the object 11 toward the 2 nd surface 11b toward the outside (see fig. 31). The method for forming the oblique crack is the same as that of embodiment 1.
Next, in embodiment 3, by switching ON/OFF of the irradiation of the laser light L by the control unit 6 while rotating the stage 2, as shown in fig. 54, the light-collecting region C is relatively moved along the 3 rd region A3 in the line a to form the modified region 12, and the formation of the modified region 12 is stopped (3 rd processing) in the regions (1 st region A1 and 2 nd region A2) other than the 3 rd region A3 of the line a.
In the 3 rd machining, the rotation direction of the table 2 is maintained from the 2 ND machining by the control of the moving unit 4 of the control unit 6, and the machining traveling direction ND is maintained in the forward direction ND1. Since the 3 rd process is the process of the 3 rd region A3, the control unit 6 performs the formation of the laser beam L by the spatial light modulator 7, and the beam shape of the light-condensing region C is set to the 3 rd shape Q3 (see fig. 52). Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the Z direction from the center of the object 11 toward the 2 nd surface 11b toward the outside (see fig. 31). The method for forming oblique cracks is the same as in embodiment 1. That is, in the 3 rd process, the 1 st formation and the 2 nd formation for forming the oblique crack can be performed similarly to the 1 st process and the 2 nd process.
Here, the 3 rd process of the 3 rd region A3 is performed continuously with the 2 nd process of the 2 nd region A2. This eliminates the need to temporarily stop the rotation of the table 2 and reverse the rotation, and shortens the time required for acceleration and deceleration of the rotation of the table 2. In the 3 rd process in the 3 rd region A3, the beam shape of the light converging region C is such that the longitudinal direction NH thereof is along the process advancing direction ND. Accordingly, a good machining result (evaluation "a") can be obtained similarly regardless of whether the machining traveling direction ND is the forward direction ND1 or the reverse direction ND2 (see fig. 53).
Then, in the 3 rd machining, the forward and backward directions of the machining traveling direction ND are not limited. However, the forward and reverse directions of the processing traveling direction ND in the 3 rd processing may be the same as the forward and reverse directions of the processing traveling direction ND in the 1 st processing and the 2 ND processing, which are continuously performed with the 3 rd processing, in terms of shortening the time due to acceleration and deceleration associated with the relative movement of the condensed region C.
That is, as described above, in the case where the processing of the 3 rd is performed after the processing of the 2 ND or in the case where the processing of the 2 ND is performed after the processing of the 3 rd, the forward and reverse directions of the processing traveling direction ND of the processing of the 3 rd may be the forward direction ND1 similarly to the processing of the 2 ND. Alternatively, in the case where the 1 st processing is followed by the 3 rd processing, or in the case where the 3 rd processing is followed by the 1 st processing, the forward and backward directions of the 3 rd processing in the processing traveling direction may be the reverse direction ND2 similarly to the 1 st processing.
Next, in embodiment 3, the 2 nd portion 15B (see fig. 31) of the object 11 is processed. The processing of the 2 nd portion 15B can be performed in the same manner as in embodiment 1 and embodiment 2. That is, in the processing of the 2 nd portion 15B, the other processing (for example, the 1 st Z processing and the 2 nd Z processing) may 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 over the entire region in the Z direction. In particular, in part 1, 15A, there is formed: the cracks 13a and 13b are inclined from the 1 st surface 11a of the object 11 toward the 2 nd surface 11b toward the outer edge 110e of the bonding region from a position inside the bonding region between the element layer 110 of the object 11 and the element layer 110R of the object 11R.
Next, as in embodiment 1 and embodiment 2, the modified region 12 and the crack 13 extending from the modified region 12 are formed along a line extending so that the removed region E is equally divided by 4 when viewed from the Z direction, and the removed region E is removed with the modified region 12 as a boundary. Thus, the semiconductor element 11K is formed from the object 11, and the object 100K including the semiconductor element 11K is obtained. Thereafter, the semiconductor element 11K is ground from the 1 st surface 11a side to form the semiconductor element 11M, and the object 100M including the semiconductor element 11M is obtained.
The laser processing according to embodiment 3 above will be described with reference to the structure of the laser processing apparatus 1. Here, the description will also be made with respect to the overlapping portions with embodiment 1 and embodiment 2. That is, the laser processing apparatus 1 is an apparatus for forming a modified region 12 by irradiating an object 11 with laser light L (laser light L1, L2), and includes at least: the laser irradiation device includes a stage 2 for supporting an object 11, an irradiation unit 3 for irradiating the object 11 supported by the stage 2 with laser light L, moving units 4 and 5 for relatively moving a condensed region C (condensed regions C1 and C2) of the laser light L with respect to the object 11, and a control unit 6 for controlling the moving units 4 and 5 and the irradiation unit 3. The irradiation unit 3 includes a spatial light modulator 7 that shapes the laser light L so that the light-collecting region C has a longitudinal direction NH when viewed from the Z direction.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 1 st processing (the 1 st processing described above), and causes the condensed region C (condensed regions C1 and C2) to move relatively along the 1 st region A1 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) in the object 11 along the 1 st region A1, and forming the oblique crack 13F extending obliquely in the Z direction from the modified region 12 toward the 2 nd surface 11b on the opposite side of the 1 st surface 11a, which is the incident surface of the object 11.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 2 nd machining process (the 2 nd machining process), and relatively moves the condensed regions C (the condensed regions C1 and C2) along the 2 nd region A2 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) on the object 11 along the 2 nd region A2, and forming the oblique crack 13F ( cracks 13a and 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st processing and the 2 nd processing, the control unit 6 controls the spatial light modulator 7 to shape the laser beam L into: the longitudinal direction NH of the light-collecting region C is inclined toward the direction approaching the larger angle between the direction of movement of the light-collecting region C, that is, the machine direction ND, from among the 1 st crystal orientation K1 and the 2 ND crystal orientation K2. In the 1 st machining process and the 2 ND machining process, the control unit 6 controls the moving units 4 and 5 to switch the forward and reverse directions of the machining traveling direction ND between the 1 st machining process and the 2 ND machining process: the direction of inclination of the long side direction NH is the same as the direction in which the oblique crack 13F extends in the machine direction ND when viewed from the Z direction.
Line a contains: a1 st region A1 including 0 °, A2 nd region A2 including 90 °, and A3 rd region A3 in a circular arc shape including 45 ° which is a region between the 1 st region A1 and the 2 nd region A2.
Then, the control unit 6 controls the irradiation unit 3 and the moving units 4 and 5 to perform the 3 rd machining process (the 3 rd machining process described above), and relatively moves the light collecting region C along the 3 rd region A3 in the line a, thereby forming the modified region 12 in the object 11 along the 3 rd region A3, and forming the oblique crack extending from the modified region 12 toward the 2 nd surface 11 b.
In the 3 rd processing, the control unit 6 controls the spatial light modulator 7 to shape the laser beam L so that the longitudinal direction NH of the light collecting region C is along the processing traveling direction ND. In particular, in the 3 rd processing, the control unit 6 controls the moving units 4 and 5 so that the forward and reverse directions of the processing traveling direction ND of the light collecting region C are identical to the forward and reverse directions of the processing traveling direction ND of one of the 1 st processing and the 2 ND processing, which are continuously performed with the 3 rd processing.
Next, the laser processing according to embodiment 3 will be described with reference to the steps of the laser processing method. That is, the laser processing method of the present embodiment is a laser processing method for forming a modified region 12 (modified regions 12a, 12 b) by irradiating a target 11 with laser light L (laser light L1, L2), and includes A1 st processing step (1 st processing described above) of relatively moving a condensed region C (condensed regions C1, C2) of the laser light L along A1 st region A1 set in a line a of the target 11, thereby forming the modified region 12 in the target 11 along the 1 st region A1, and forming oblique cracks 13F ( cracks 13a, 13 b) extending obliquely to the Z direction from the modified region 12 toward a 2 nd surface 11b of the target 11.
The laser processing method of the present embodiment includes A2 nd processing step of relatively moving the light collecting region C along the 2 nd region A2 in the line a, thereby forming the modified region 12 in the object 11 along the 2 nd region A2 and forming the oblique crack 13F extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st and 2 ND processing steps, the forward and reverse directions of the processing traveling direction ND, which is the moving direction of the light collecting region C, are switched between the 1 st and 2 ND processing steps.
On the other hand, the laser processing method of the present embodiment includes A3 rd processing step (the 3 rd processing described above) of relatively moving the light collecting region C along the 3 rd region A3 in the line a, thereby forming the modified region 12 in the object 11 along the 3 rd region A3, and forming the oblique crack 13F extending from the modified region 12 toward the 2 nd surface 11 b.
In the 3 rd machining step, the laser beam L is formed such that the longitudinal direction NH of the light collecting region C is along the machining traveling direction ND.
As described above, according to the laser processing apparatus 1 and the laser processing method of the present embodiment, since the 1 st processing and the 2 nd processing are performed in the same manner as in the 1 st embodiment, the same effects as in the 1 st embodiment can be exhibited. In addition, according to the laser processing apparatus 1 and the laser processing method of the present embodiment, in the 3 rd process, the laser light L is formed such that the longitudinal direction NH of the light collecting region C is along the processing traveling direction ND. Therefore, as shown in the above-mentioned findings, the quality of the trimming surface of the region including the 45 ° point becomes better.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 controls the moving units 4 and 5 in the 3 rd processing, so that the forward and backward directions of the processing traveling direction ND of the light converging region C are identical to the forward and backward directions of the processing traveling direction ND of one of the 1 st processing and the 2 ND processing, which are continuously performed with the 3 rd processing. In this case, the time required for acceleration and deceleration for relative movement of the light collecting region C is shortened, and the efficiency reduction can be suppressed.
In the 3 rd machining process, the longitudinal direction NH of the light collecting region C is along the machining traveling direction ND, and is not limited to the case where the longitudinal direction NH and the machining traveling direction ND are strictly aligned, but includes the case where the longitudinal direction NH has an inclination of about 6 ° with respect to the machining traveling direction ND. The angular range of the 3 rd region A3 is not limited to 40 ° to 50 °, and may be arbitrarily selected from a range of 45 ° ± 10 °.
Further, between one processing (for example, the 3 rd processing) and the other processing (for example, the 2 nd processing), the irradiation of the laser light L may be turned OFF, and a time for maintaining the rotation of the stage 2 (that is, an idling time for idling the stage 2) may be generated. In this case, during the idling time period, the control unit 6 may execute the following processing: the modulation pattern displayed on the spatial light modulator 7 is switched to a modulation pattern for shaping the shape of the light collecting region C into a shape (for example, the 3 rd shape Q3) at the time of the other processing.
In addition, the laser processing apparatus 1 and the laser processing method according to embodiment 3 may be arbitrarily selected from the structures according to embodiment 1 and embodiment 2 and the structures according to the modification examples of embodiment 1 and embodiment 2.
[ embodiment 4 of laser processing ]
Next, another embodiment of the laser processing for forming oblique cracks during the trimming processing will be described. As described above, for example, in the case of performing the laser processing of embodiment 1 and embodiment 2, there is room for improvement in obtaining a better processing result (for example, the above-described evaluation "a") in the region around 45 ° of the line a. In particular, when the point where the line a defining the machining direction ND is orthogonal to the 2 ND crystal orientation K2 is 0 °, the point where the line a is orthogonal to the 1 st crystal orientation K1 is 90 °, and the point between the line a 0 ° and 90 ° is 45 °, the quality of the trimming surface is likely to be degraded when the direction of the longitudinal direction NH of the beam shape and the oblique direction of the oblique crack are on opposite sides of the machining direction ND during machining at the point of 45 °.
In contrast, as described above, the region including 45 ° of the line a is set independently of the 1 st region A1 and the 2 ND region A2, and in this region, if the direction of the longitudinal direction NH of the beam shape is made to be along the machine direction ND, the quality of the trimming surface becomes better. In the present embodiment, laser processing is performed based on the above findings. Next, laser processing according to embodiment 4 will be described.
In embodiment 4, as in embodiment 3, the object 11 includes: (100) A plane, one (110) plane, the other (110) plane, a1 st crystal orientation K1 orthogonal to the one (110) plane, and a2 nd crystal orientation K2 orthogonal to the other (110) plane. The point at which the line a intersects with the 2 nd crystal orientation K2 is 0 °, the point at which the line a intersects with the 1 st crystal orientation K1 is 90 °, and the point between 0 ° and 90 ° of the line a is 45 °.
In embodiment 4, the line a includes: a1 st region A1 including 0 °, A2 nd region A2 including 90 °, and A3 rd region A3 in a circular arc shape including 45 ° which is a region between the 1 st region A1 and the 2 nd region A2.
Here, as an example, the 1 st region A1 is 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 °, and the 2 nd region A2 is 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 °. Then, the 3 rd region A3 is 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, the 3 rd region A3 is interposed between the 1 st region A1 and the 2 nd region A2, and has a width of 10 ° with a 90 ° interval.
In embodiment 4 of the object 11, first, the 1 st portion 15A (see fig. 31) of the object 11 is processed. That is, in embodiment 4, the 1 st process similar to embodiment 2 is performed. More specifically, as shown in fig. 55, first, the control unit 6 switches ON/OFF of the irradiation of the laser light L while rotating the stage 2, thereby relatively moving the light-collecting region C along the 1 st region A1 of the line a to form the modified region 12, and the formation of the modified region 12 is stopped in regions (the 2 nd region A2 and the 3 rd region A3) other than the 1 st region A1 of the line a (1 st processing).
In the 1 st machining, the rotation direction of the table 2 is controlled by the control of the moving unit 4 of the control unit 6 so that the machining traveling direction ND becomes the forward direction ND1. Since the 1 st process is the process of the 1 st region A1, the control unit 6 controls the spatial light modulator 7 to form the laser beam L so that the beam shape of the light-condensing region C becomes the 1 st shape Q1. Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the Z direction from the center of the object 11 toward the 2 nd surface 11b toward the outside (see fig. 31). The method for forming oblique cracks is the same as in embodiment 1.
Next, in embodiment 4, the control unit 6 switches ON/OFF of the irradiation of the laser beam L while rotating the stage 2, thereby forming the modified region 12 by relatively moving the condensed region C along the 2 nd region A2 in the line a as shown in fig. 55, and the formation of the modified region 12 is stopped (2 nd processing) in the regions (1 st region A1 and 3 rd region A3) other than the 2 nd region A2 of the line a.
In the 2 ND machining, the rotation direction of the table 2 is controlled by the control of the moving unit 4 of the control unit 6, so that the machining traveling direction ND is maintained in the same forward direction ND1 as in the 1 st machining. That is, between the 1 st machining and the 2 ND machining, the forward and reverse directions (forward direction ND1 or reverse direction ND 2) of the machining traveling direction ND are made the same. Since the 2 nd process is the process of the 2 nd region A2, the control unit 6 controls the spatial light modulator 7 to form the laser beam L so that the beam shape of the light-condensing region C becomes the 2 nd shape Q2. Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the Z direction from the center of the object 11 toward the 2 nd surface 11b toward the outside (see fig. 31). The method for forming the oblique crack is the same as that of embodiment 1. Note that, when the 1 st machining and the 2 ND machining make the forward and backward directions of the machining traveling direction ND identical, the machining traveling direction ND is not limited to the forward direction ND1 described above, and may be the reverse direction ND2.
Next, in embodiment 4, by switching ON/OFF of the irradiation of the laser light L by the control unit 6 while rotating the stage 2, as shown in fig. 55, the light-collecting region C is relatively moved along the 3 rd region A3 in the line a to form the modified region 12, and the formation of the modified region 12 is stopped (3 rd processing) in the regions (1 st region A1 and 2 nd region A2) other than the 3 rd region A3 of the line a.
In the 3 rd machining, the rotation direction of the table 2 is maintained from the 2 ND machining by the control of the moving unit 4 of the control unit 6, and the machining traveling direction ND is maintained in the forward direction ND1. Since the 3 rd process is the process of the 3 rd region A3, the control unit 6 performs the formation of the laser beam L by the spatial light modulator 7, and the beam shape of the light-condensing region C is set to the 3 rd shape Q3 (see fig. 52). Here, the extending direction CD of the oblique crack is set to be the positive direction CD1 so as to be inclined in the Z direction from the center of the object 11 toward the 2 nd surface 11b toward the outside (see fig. 31). The method for forming oblique cracks is the same as in embodiment 1. That is, in the 3 rd process, the 1 st formation and the 2 nd formation for forming the oblique crack can be performed similarly to the 1 st process and the 2 nd process.
In the 3 rd process in the 3 rd region A3, the beam shape of the light converging region C is such that the longitudinal direction NH thereof is along the process advancing direction ND. Accordingly, a good machining result (evaluation "a") can be obtained similarly regardless of whether the machining traveling direction ND is the forward direction ND1 or the reverse direction ND2 (see fig. 53).
Then, in the 3 rd machining, the forward and backward directions of the machining traveling direction ND are not limited. However, from the viewpoint of shortening the time due to acceleration and deceleration associated with the relative movement of the light collecting region C, the forward and reverse directions of the processing travel direction ND of the 3 rd processing may be the same for the processing travel direction ND of the 1 st processing and the processing travel direction ND of the 2 ND processing.
Next, in embodiment 4, the 2 nd portion 15B (see fig. 31) of the object 11 is processed. The processing of the 2 nd portion 15B can be performed in the same manner as in embodiment 1 and embodiment 2. That is, in the processing of the 2 nd portion 15B, the other processing (for example, the 1 st Z processing and the 2 nd Z processing) may 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 over the entire region in the Z direction. In particular, in part 1, 15A, there is formed: the cracks 13a and 13b are inclined from the 1 st surface 11a of the object 11 toward the 2 nd surface 11b toward the outer edge 110e of the bonding region from a position inside the bonding region between the element layer 110 of the object 11 and the element layer 110R of the object 11R.
Next, as in embodiment 1 and embodiment 2, the modified region 12 and the crack 13 extending from the modified region 12 are formed along a line extending so that the removed region E is equally divided by 4 when viewed from the Z direction, and the removed region E is removed with the modified region 12 as a boundary. Thus, the semiconductor element 11K is formed from the object 11, and the object 100K including the semiconductor element 11K is obtained. Thereafter, the semiconductor element 11K is ground from the 1 st surface 11a side to form the semiconductor element 11M, and the object 100M including the semiconductor element 11M is obtained.
The laser processing according to embodiment 4 above will be described with reference to the structure of the laser processing apparatus 1. That is, the laser processing apparatus 1 is an apparatus for forming a modified region 12 by irradiating an object 11 with laser light L (laser light L1, L2), and includes at least: the laser irradiation device includes a stage 2 for supporting an object 11, an irradiation unit 3 for irradiating the object 11 supported by the stage 2 with laser light L, moving units 4 and 5 for relatively moving a condensed region C (condensed regions C1 and C2) of the laser light L with respect to the object 11, and a control unit 6 for controlling the moving units 4 and 5 and the irradiation unit 3. The irradiation unit 3 includes a spatial light modulator 7 that shapes the laser light L so that the light-collecting region C has a longitudinal direction NH when viewed from the Z direction.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 1 st processing (the 1 st processing), and causes the condensed regions C (the condensed regions C1 and C2) to move relatively along the 1 st region A1 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) in the object 11 along the 1 st region A1, and forming oblique cracks 13F ( cracks 13a and 13 b) extending obliquely in the Z direction from the modified region 12 toward the 2 nd surface 11b on the opposite side of the 1 st surface 11a, which is the incident surface of the object 11.
The control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 2 nd machining process (the 2 nd machining process), and relatively moves the condensed regions C (the condensed regions C1 and C2) along the 2 nd region A2 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) on the object 11 along the 2 nd region A2, and forming the oblique crack 13F ( cracks 13a and 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st processing and the 2 nd processing, the control unit 6 controls the spatial light modulator 7 to shape the laser beam L into: the longitudinal direction NH of the light collecting region C is inclined in the direction approaching the larger angle between the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 and the direction of movement of the light collecting region C, that is, the machining direction ND, and the machining direction ND of the 1 st machining process and the machining direction ND of the 2 ND machining process are the same in the forward and reverse directions.
On the other hand, the control unit 6 controls the irradiation unit 3 and the movement units 4 and 5 to perform the 3 rd machining process (the 3 rd machining process described above), and relatively moves the condensed region C (the condensed regions C1 and C2) along the 3 rd region A3 in the line a, thereby forming the modified region 12 (modified regions 12a and 12 b) on the object 11 along the 3 rd region A3, and forming the oblique crack 13F ( cracks 13a and 13 b) extending from the modified region 12 toward the 2 nd surface 11 b. In particular, the control unit 6 controls the spatial light modulator 7 in the 3 rd processing, so as to shape the laser beam L such that the longitudinal direction NH of the light collecting region C is along the processing traveling direction ND.
Next, the laser processing according to embodiment 4 above will be described with reference to the steps of the laser processing method. That is, the laser processing method of the present embodiment is a method for forming the modified region 12 by irradiating the object 11 with laser light L (laser light L1, L2), and includes A1 st processing step (1 st processing described above) of relatively moving the condensed region C (condensed regions C1, C2) along A1 st region A1 set in a line a of the object 11, thereby forming the modified region 12 (modified regions 12a, 12 b) in the object 11 along the 1 st region A1, and forming oblique cracks 13F ( cracks 13a, 13 b) extending obliquely in the Z direction from the modified region 12 toward a 2 nd surface 11b on the opposite side of the 1 st surface 11a, which is an incident surface of the object 11.
The laser processing method of the present embodiment includes A2 nd processing step (the 2 nd processing step) of relatively moving the condensed region C (condensed regions C1, C2) along the 2 nd region A2 in the line a, thereby forming the modified region 12 (modified regions 12a, 12 b) in the object 11 along the 2 nd region A2, and forming the oblique crack 13F ( cracks 13a, 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 1 st and 2 nd processing steps, the laser light L is formed as: the light-collecting region C has a longitudinal direction NH when viewed from the Z direction, and the longitudinal direction NH of the light-collecting region C is inclined with respect to the machine direction ND toward one of the 1 st crystal orientation K1 and the 2 ND crystal orientation K2 that is larger than the angle between the machine direction ND and the movement direction of the light-collecting region C, and the forward and reverse directions of the machine direction ND in the 1 st machining step and the 2 ND machining step are the same.
On the other hand, the laser processing method of the present embodiment includes A3 rd processing step (3 rd processing described above) of relatively moving the condensed region C (condensed regions C1, C2) along A3 rd region A3 in the line a, thereby forming the modified region 12 (modified regions 12a, 12 b) in the object 11 along the 3 rd region A3, and forming the oblique crack 13F ( cracks 13a, 13 b) extending from the modified region 12 toward the 2 nd surface 11 b.
In the 3 rd processing step, the spatial light modulator 7 is controlled so that the laser beam L is formed such that the longitudinal direction NH of the light collecting region C is along the processing direction ND.
As described above, in the laser processing apparatus 1 and the laser processing method according to the present embodiment, the 1 st process and the 2 nd process are performed in the same manner as in embodiment 2, and therefore the same effects as in embodiment 2 can be exhibited. In the laser processing apparatus 1 and the laser processing method according to the present embodiment, the 3 rd region A3 including the 45 ° point is interposed between the 1 st region A1 and the 2 nd region A2. In the 3 rd process of the 3 rd region A3, the longitudinal direction NH of the condensed region C of the laser light L is along the process advancing direction ND. Therefore, as shown in the above-mentioned findings, the quality of the trimming surface of the region including the 45 ° point becomes better. As described above, according to the laser processing apparatus 1 and the laser processing method of the present embodiment, oblique cracks can be formed while suppressing the quality degradation of the trimming surface of the object 11.
In the laser processing apparatus 1 and the laser processing method according to the present embodiment, at least the forward and backward directions of the processing travel direction ND of the 1 st processing and the 2 ND processing are the same. Thus, the time required for acceleration and deceleration of the relative movement of the condensed region C of the laser light L can be reduced as compared with the case where the forward and backward directions of the processing travel direction ND are switched between the 1 st processing and the 2 ND processing.
In the laser processing apparatus 1 according to the present embodiment, the control unit 6 may control the moving units 4 and 5 so that the processing traveling direction ND of the light converging region C is the same as the processing traveling direction ND of the 1 st processing and the 2 ND processing in the 3 rd processing. In this case, the 1 st machining process, the 2 ND machining process, and the 3 rd machining process are identical in the forward and backward directions of the machining traveling direction ND. This shortens the time required for acceleration and deceleration for relative movement of the light collecting region C, and suppresses the efficiency from decreasing.
In addition, the laser processing apparatus 1 and the laser processing method according to embodiment 4 may be arbitrarily selected to use the structures according to embodiment 1, embodiment 2, and embodiment 3, and the structures according to the modification examples of embodiment 1, embodiment 2, and embodiment 3.
In embodiment 3 and embodiment 4, the order of the 1 st process, the 2 nd process, and the 3 rd process is arbitrary.
[ Industrial applicability ]
Provided are a laser processing device and a laser processing method, which can more appropriately set the processing traveling direction according to the crystal structure of an object.
Symbol description
1 … … laser processing device; 2 … … mounting table (supporting part); 3 … … irradiation section; 4. 5 … … moving parts; 6 … … control part; 7 … … spatial light modulator; 11 … … object; 11a … …, 1 st side (incident side); 11b … …, 2 nd (opposite); 12. 12a, 12b … … modified region; 13. 13a, 13b … … cracks; 13F … … oblique crack; 33 … … condenser lens; a1 … … region 1; a2 … … region 2; a3 … … region 3; k1 … … crystal orientation 1; crystal orientation K2 … …, 2; l … … laser; C. c1, C2 … … light focusing regions; ND … … machines the direction of travel.

Claims (19)

1. A laser processing apparatus, wherein,
is a laser processing device for forming a modified region by irradiating an object having a crystal structure with laser light,
the device is provided with:
a support section for supporting the object;
an irradiation unit configured to irradiate the laser beam toward the object supported by the support unit;
a moving unit for moving a condensed region of the laser light relative to the object; and
a control unit for controlling the moving unit and the irradiation unit,
an annular line including an arc-shaped 1 st region and an arc-shaped 2 nd region is set on the object as viewed in a Z direction intersecting the incident surface of the laser beam,
The irradiation part has a shaping part for shaping the laser,
the control unit performs:
a 1 st processing step of forming the modified region in the object along the 1 st region by controlling the irradiation section and the movement section so as to relatively move the light collecting region along the 1 st region in the line, and forming an oblique crack extending obliquely with respect to the Z direction from the modified region toward a surface opposite to the incident surface of the object; and
a 2 nd processing step of forming the modified region in the object along the 2 nd region by controlling the irradiation section and the movement section so as to relatively move the light collecting region along the 2 nd region in the line, and forming the oblique crack extending from the modified region toward the opposite surface,
in the 1 st machining process and the 2 nd machining process, the control unit switches a forward direction and a backward direction of a machining traveling direction, which is a moving direction of the light collecting region, between the 1 st machining process and the 2 nd machining process.
2. The laser processing apparatus according to claim 1, wherein,
The object includes: parts 1 and 2 arranged in this order from the opposite surface side along the Z direction,
the control unit executes the 1 st machining process and the 2 nd machining process while switching the forward and backward directions of the machining traveling direction for the 1 st part, and executes another machining process different from the 1 st machining process and the 2 nd machining process for the 2 nd part,
in the other processing, the control unit controls the irradiation unit and the movement unit so that the direction of the processing is the same throughout the entire line, and the light converging region is relatively moved along the line, thereby forming the modified region and the crack extending from the modified region in the Z direction in the object along the line.
3. The laser processing apparatus according to claim 2, wherein,
in the other processing, the control unit controls the forming unit to form the laser beam into: the light-condensing region has a long-side direction when viewed from the Z direction, and the long-side direction of the light-condensing region is along the machine direction.
4. The laser processing apparatus as claimed in any one of claims 1 to 3, wherein,
the object includes: a joining region to be joined with the other member,
in the 1 st processing and the 2 nd processing, the control unit may form: the oblique crack is inclined so as to be directed from a position inside the joint region toward an outer edge of the joint region as being directed from the incident surface toward the opposite surface.
5. The laser processing apparatus as claimed in any one of claims 1 to 4, wherein,
the object has a crystal structure including: (100) A surface, one (110) surface, another (110) surface, a 1 st crystal orientation orthogonal to the one (110) surface, and a 2 nd crystal orientation orthogonal to the other (110) surface, and the object is supported by the support portion so that the (100) surface becomes the incident surface,
in the 1 st machining process and the 2 nd machining process, the control unit:
controlling the forming section so as to form the laser into: the light-collecting region has a long-side direction when viewed from the Z direction, and the long-side direction is inclined with respect to the machine direction in a direction approaching one of the 1 st crystal orientation and the 2 nd crystal orientation, which is larger than an angle between the machine direction, which is a moving direction of the light-collecting region.
6. The laser processing apparatus according to claim 5, wherein,
when the point at which the 2 nd crystal orientation is perpendicular to the line is 0 °, the point at which the 1 st crystal orientation is perpendicular to the line is 90 °, and the point between the 0 ° and the 90 ° of the line is 45 °, the 1 st region includes the region from 0 ° to 45 °,
the 2 nd region includes the region from 45 ° to 90 °.
7. A laser processing apparatus as claimed in claim 5 or 6, wherein,
in the 1 st machining process and the 2 nd machining process, the control unit controls the moving unit so that the forward and reverse directions of the machining traveling direction are switched between the 1 st machining process and the 2 nd machining process: the direction of inclination of the long side direction is the same as the direction in which the oblique crack extends with respect to the machine direction when viewed from the Z direction.
8. A laser processing apparatus as claimed in claim 2 or 3, wherein,
the object has a crystal structure including: (100) A surface, one (110) surface, another (110) surface, a 1 st crystal orientation orthogonal to the one (110) surface, and a 2 nd crystal orientation orthogonal to the other (110) surface, and the object is supported by the support portion so that the (100) surface becomes the incident surface,
In the other processing, the control unit does not switch the processing traveling direction, and executes: a 1 st Z processing step of forming the modified region on the object along the 1 st region by relatively moving the light collecting region along the 1 st region in the line, and forming a crack extending from the modified region in the Z direction; and a 2Z-th processing step of relatively moving the light-collecting region along the 2 nd region of the line to form the modified region on the object along the 2 nd region and to form a crack extending from the modified region in the Z direction,
in the 1 st and 2 nd Z processing, the control unit controls the forming unit to form the laser beam into: the light-collecting region has a long-side direction when viewed from the Z direction, and the long-side direction is inclined with respect to the machine direction in a direction approaching one of the 1 st crystal orientation and the 2 nd crystal orientation, which is at a larger angle with respect to the machine direction.
9. The laser processing apparatus as claimed in claim 5 or 8, wherein,
When the point at which the 2 nd crystal orientation is perpendicular to the line is 0 °, the point at which the 1 st crystal orientation is perpendicular to the line is 90 °, and the point between the 0 ° and 90 ° of the line is 45 °, the line contains: the 1 st region including the 0 DEG, the 2 nd region including the 90 DEG, and a 3 rd region which is a region between the 1 st region and the 2 nd region and includes the 45 DEG in a circular arc shape,
the control unit performs a 3 rd processing operation of relatively moving the light collecting region along the 3 rd region in the line by controlling the irradiation unit and the movement unit, thereby forming the modified region on the object along the 3 rd region and forming the oblique crack extending from the modified region toward the opposite surface,
in the 3 rd processing, the control unit controls the forming unit to form the laser beam into: the light-collecting region has a long-side direction when viewed from the Z direction, and the long-side direction is along the machine direction.
10. The laser processing apparatus according to claim 9, wherein,
in the 3 rd processing step, the control unit controls the moving unit so that the forward and reverse directions of the processing traveling direction of the light collecting region are identical to the forward and reverse directions of the processing traveling direction of one of the 1 st processing step and the 2 nd processing step, which is continuously performed with the 3 rd processing step.
11. The laser processing apparatus as claimed in claim 9 or 10, wherein,
in the 1 st machining process and the 2 nd machining process, the control unit controls the moving unit so as to switch the forward and backward directions of the machining traveling direction between the 1 st machining process and the 2 nd machining process: the direction of inclination of the long side direction is the same as the direction in which the oblique crack extends with respect to the machine direction when viewed from the Z direction.
12. The laser processing apparatus as claimed in any one of claims 1 to 11, wherein,
in the 1 st machining process and the 2 nd machining process, the control unit executes:
a 1 st formation process of forming a 1 st modified region as the modified region and a crack extending from the 1 st modified region on the object by setting a position of the light-collecting region in the Z direction to be a 1 st Z position and relatively moving the light-collecting region along the line; and
a 2 nd formation process of setting a position of the light collecting region in the Z direction to a 2 nd Z position on the incident surface side from the 1 st Z position, and relatively moving the light collecting region along the line to form a 2 nd modified region as the modified region and a crack extending from the 2 nd modified region,
In the 1 st forming process, the control unit sets the position of the light collecting region in the Y direction intersecting the machine direction and the Z direction to a 1 st Y position,
in the 2 nd forming process, the control unit sets the position of the light collecting region in the Y direction to a 2 nd Y position shifted from the 1 st Y position, and forms the laser beam by control of the forming unit into: the shape of the light collecting region in the YZ plane including the Y direction and the Z direction is an inclined shape inclined toward the shift direction at least in the incidence plane side than the center of the light collecting region, so that the oblique crack is formed in the YZ plane so as to be inclined toward the shift direction.
13. The laser processing apparatus as claimed in claim 12, wherein,
the forming part comprises: a spatial light modulator for modulating the laser light according to a modulation pattern to thereby shape the laser light,
the irradiation section includes: a condenser lens for condensing the laser light from the spatial light modulator toward the object,
in the 2 nd forming process, the control unit modulates the laser beam so that the shape of the light converging region becomes the inclined shape by control of the modulation pattern displayed on the spatial light modulator, thereby forming the laser beam.
14. The laser processing apparatus as claimed in claim 13, wherein,
the modulation pattern includes: a coma aberration pattern for imparting coma aberration to the laser beam,
in the 2 nd formation process, the control unit controls the magnitude of the coma aberration according to the coma aberration pattern, and thereby performs 1 st pattern control for making the shape of the light-condensing region the inclined shape.
15. The laser processing apparatus as claimed in claim 13 or 14, wherein,
the modulation pattern includes: a spherical aberration correction pattern for correcting the spherical aberration of the laser light,
in the 2 nd formation process, the control unit shifts the center of the spherical aberration correction pattern in the Y direction with respect to the center of the entrance pupil plane of the condenser lens, thereby performing 2 nd pattern control for making the shape of the condenser region the oblique shape.
16. The laser processing apparatus as claimed in any one of claims 13 to 15, wherein,
in the 2 nd forming process, the control unit performs 3 rd pattern control of making the shape of the light collecting region the oblique shape by displaying the modulation pattern asymmetric with respect to the axis along the machining traveling direction on the spatial light modulator.
17. The laser processing apparatus as claimed in any one of claims 13 to 16, wherein,
the modulation pattern includes: an elliptical pattern for forming the shape of the light-collecting region in an XY plane including an X direction intersecting the Y direction and the Z direction and the Y direction into an elliptical shape having a long side in the X direction,
in the 2 nd forming process, the control unit performs 4 th pattern control for making the shape of the light collecting region be the inclined shape by displaying 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.
18. The laser processing apparatus as claimed in any one of claims 13 to 17, wherein,
in the 2 nd forming process, the control unit displays the modulation pattern for forming the condensed spots of the plurality of laser beams aligned in the shift direction in the YZ plane on the spatial light modulator, and performs 5 th pattern control for making the shape of the condensed area including the plurality of condensed spots the inclined shape.
19. A laser processing method, wherein,
A laser processing method for forming a modified region by irradiating an object having a crystal structure with laser light, comprising:
a 1 st processing step of forming the modified region in the object along a 1 st region of a line set in the object by relatively moving the condensed region of the laser light, and forming an oblique crack extending obliquely with respect to a Z direction intersecting the incident surface from the modified region toward an opposite surface opposite to the incident surface of the laser light of the object along the 1 st region; and
a 2 nd processing step of forming the modified region on the object along the 2 nd region by relatively moving the light collecting region along the 2 nd region of the line, and forming the oblique crack extending from the modified region toward the opposite surface,
the object is provided with the circular ring-shaped line comprising the circular arc-shaped 1 st area and the circular arc-shaped 2 nd area when viewed from the Z direction,
in the 1 st processing step and the 2 nd processing step, the forward and reverse directions of the processing proceeding direction, which is the moving direction of the light collecting region, are switched between the 1 st processing step and the 2 nd processing step.
CN202180061227.5A 2020-07-15 2021-03-29 Laser processing device and laser processing method Pending CN116075389A (en)

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