WO2024057780A1 - Laser processing device, and laser processing method - Google Patents

Laser processing device, and laser processing method Download PDF

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Publication number
WO2024057780A1
WO2024057780A1 PCT/JP2023/028946 JP2023028946W WO2024057780A1 WO 2024057780 A1 WO2024057780 A1 WO 2024057780A1 JP 2023028946 W JP2023028946 W JP 2023028946W WO 2024057780 A1 WO2024057780 A1 WO 2024057780A1
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Prior art keywords
line
laser
laser processing
extension part
spatial light
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PCT/JP2023/028946
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French (fr)
Japanese (ja)
Inventor
剛志 坂本
孝文 荻原
雅輝 小柳津
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浜松ホトニクス株式会社
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Publication of WO2024057780A1 publication Critical patent/WO2024057780A1/en

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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
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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

Definitions

  • the present disclosure relates to a laser processing device and a laser processing method.
  • a support part that supports a target object, a light source that emits laser light, a spatial light modulator that modulates the laser light emitted from the light source, and a laser light modulated by the spatial light modulator that focuses the laser light on the target object.
  • a laser processing apparatus includes a condensing section and an image transfer section that transfers an image of a laser beam in a spatial light modulator onto an entrance pupil plane of the condensing section (see, for example, Patent Document 1).
  • a laser processing device such as that described above can form modified regions and cracks in a target object. Formation of such modified regions and cracks can be applied to various processes, such as dicing to divide an object into a plurality of chips, trimming to remove unnecessary parts from the object, and the like.
  • An object of the present disclosure is to provide a laser processing device and a laser processing method that can form appropriate modified regions and cracks in a target object depending on the processing.
  • a laser processing apparatus includes [1] "a support section that supports a target object, a light source that emits laser light, and a modulation pattern that displays the laser beam emitted from the light source.” a spatial light modulator that modulates the laser beam, a focusing section that focuses the laser beam modulated by the spatial light modulator on the object, and a driving section that drives at least one of the support section and the focusing section. , a control unit that controls at least the spatial light modulator and the drive unit, and the control unit is configured such that the beam shape of the laser beam at the focused spot of the laser beam is radial from the center and the center.
  • a modulation pattern including a trefoil aberration pattern is formed in the space so that the beam shape includes a first extension part, a second extension part, and a third extension part extending in the space and has the highest intensity in the center part.
  • the focused spot moves relatively along a line set on the object while the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator.
  • a laser processing apparatus in which at least one of the supporting section and the light condensing section is driven by the driving section.
  • the beam shape of the laser beam at the focused spot is formed into a central portion, a first extending portion, a second extending portion, and a third extending portion extending radially from the central portion.
  • the focused spot is relatively moved along a line set on the object, with the focus having the highest intensity at the center.
  • the state of at least one of the modified region and the cracks formed in the object can be adjusted. Therefore, according to the laser processing apparatus described in [1] above, appropriate modified regions and cracks can be formed in the object according to the processing.
  • a laser processing apparatus includes [2] "forming a modified region in the target object along the line, and from the modified region in the incident direction of the laser beam and in the extending direction of the line.
  • [2] "forming a crack in the object along a first surface parallel to both directions of Displaying the modulation pattern including the trefoil aberration pattern on the spatial light modulator such that the second extension part is located at and the third extension part is located on the other side with respect to the line.
  • the laser processing apparatus described in [1] above.
  • the width of the crack in the laser beam incident direction can be made smaller than, for example, when the modulation pattern does not include a trefoil aberration pattern.
  • the laser processing device may be the laser processing device described in [2] above, [3] "wherein the control unit causes the spatial light modulator to display the modulation pattern including the trefoil aberration pattern such that the first extension portion is located in front of the direction in which the focused spot moves relatively along the line, and the second extension portion and the third extension portion are located in the rear of the direction.”
  • the control unit causes the spatial light modulator to display the modulation pattern including the trefoil aberration pattern such that the first extension portion is located in front of the direction in which the focused spot moves relatively along the line, and the second extension portion and the third extension portion are located in the rear of the direction.
  • the laser processing device includes [4] “In the case where the focused spot is relatively moved along each of a first line and a second line set on the object as the line, When the direction in which the focused spot is relatively moved along the first line is different from the direction in which the focused spot is relatively moved along the second line, the control unit The first extension part is located on the front side in the direction in which the focused spot moves relatively along each of the first line and the second line, and the second extension part and the The laser processing apparatus according to [3] above may change the direction of the modulation pattern including the trefoil aberration pattern so that the third extension portion is located.
  • the direction in which the focused spot is relatively moved along the first line and the direction in which the focused spot is relatively moved along the second line are different. Even when different, the first extension part is located on the front side in the direction in which the focused spot moves relatively along each of the first line and the second line, and the second extension part is located on the rear side in the direction. The state in which the third extension portion is located can be easily and reliably realized.
  • the laser processing device provides [5] “When the control unit sets a width of at least one of the modified region and the crack in the incident direction of the laser beam as a first width, If the modulation pattern including the trefoil aberration pattern having a first trefoil aberration intensity is displayed on the spatial light modulator, and the width of at least one of the patterns is a second width smaller than the first width, The laser processing device according to any one of [2] to [4] above, wherein the modulation pattern including the trefoil aberration pattern having a second trefoil aberration intensity stronger than the trefoil aberration intensity is displayed on the spatial light modulator. ”. According to the laser processing apparatus described in [5], the width of at least one of the modified region and the crack in the incident direction of the laser beam can be set to an appropriate width depending on the processing.
  • the laser processing apparatus includes [6] "forming a modified region in the object along the line, and from the modified region in the incident direction of the laser beam and in the extending direction of the line.
  • a crack is formed in the object along a second surface that is inclined with respect to a first surface that is parallel to both directions, a region on the opposite side to the incident side of the laser beam is perpendicular to the first surface.
  • the control section is configured such that the first extending section is located on the one side with respect to the line and the second surface is inclined with respect to the line.
  • the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator so that the second extension part and the third extension part are located on the other side. It may also be a "laser processing device". According to the laser processing apparatus described in [6], the crack extending from the modified region can be inclined to a desired side.
  • the laser processing device includes [7] “In the case where the focused spot is relatively moved along each of a first line and a second line set on the object as the line, When the direction in which the focused spot is relatively moved along the first line is different from the direction in which the focused spot is relatively moved along the second line, the control unit The first extending portion is located on the one side with respect to each of the first line and the second line, and the second extending portion is located on the other side with respect to each of the first line and the second line.
  • the laser processing apparatus may change the direction of the modulation pattern including the trefoil aberration pattern so that the trefoil aberration pattern and the third extension portion are located.
  • the direction in which the focused spot is relatively moved along the first line and the direction in which the focused spot is relatively moved along the second line are different. Even in different cases, the first extension part is located on one side with respect to each of the first line and the second line, and the second extension part is located on the other side with respect to each of the first line and the second line. It is possible to easily and reliably realize the state in which the third extension part and the third extension part are located.
  • the laser processing device includes [8] “When the angle between the first surface and the second surface is the first angle, the control unit controls the first trefoil aberration intensity.
  • the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator and the angle is a second angle larger than the first angle, a second trefoil aberration intensity stronger than the first trefoil aberration intensity is used.
  • the laser processing apparatus may display the modulation pattern including the trefoil aberration pattern of aberration intensity on the spatial light modulator. According to the laser processing apparatus described in [8], the angle at which the crack extending from the modified region is inclined can be set to an appropriate angle depending on the processing.
  • a laser processing method includes [9] "a supporting part that supports a target object, a light source that emits a laser beam, and a modulation pattern that is displayed, so that the laser beam that is emitted from the light source is a spatial light modulator that modulates the laser beam, a focusing section that focuses the laser beam modulated by the spatial light modulator on the object, and a driving section that drives at least one of the support section and the focusing section.
  • a laser processing method carried out in a laser processing apparatus comprising: a beam shape of the laser light at a focused spot of the laser light includes a center portion and a first extension portion extending radially from the center portion; , displaying a modulation pattern including a trefoil aberration pattern on the spatial light modulator so as to have a beam shape that includes a second extension part and a third extension part and has the highest intensity at the center; The supporting portion and a step of causing the driving section to drive at least one of the light condensing sections.
  • the beam shape of the laser beam at the condensed spot includes a central portion, a first extending portion, a second extending portion, and a third extending portion extending radially from the central portion.
  • the focused spot is relatively moved along a line set on the object, with the focus having the highest intensity at the center.
  • the state of at least one of the modified region and the cracks formed in the object can be adjusted. Therefore, according to the laser processing method described in [9] above, appropriate modified regions and cracks can be formed in the object depending on the processing.
  • FIG. 1 is a diagram showing the configuration of a laser processing apparatus according to an embodiment.
  • FIG. 2 is a diagram showing the configuration of the irradiation section shown in FIG. 1.
  • 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 diagram showing an example of a trefoil aberration pattern.
  • FIG. 6 is a diagram showing an example of a focused state of laser light and an example of a beam shape of the laser light at the focused spot.
  • FIG. 7 is a diagram showing an example of a beam shape of a laser beam for each trefoil aberration intensity.
  • FIG. 1 is a diagram showing the configuration of a laser processing apparatus according to an embodiment.
  • FIG. 2 is a diagram showing the configuration of the irradiation section shown in FIG. 1.
  • FIG. 3 is a diagram showing the 4f lens unit shown in FIG. 2.
  • FIG. 4 is
  • FIG. 8 is a diagram showing an example of a beam shape of laser light modulated by a trefoil aberration pattern.
  • FIG. 9 is a diagram showing an example of a beam shape of a laser beam modulated by a trefoil aberration pattern and an astigmatism pattern.
  • FIG. 10 is a diagram showing an example of a beam shape of laser light modulated by a trefoil aberration pattern, an astigmatism pattern, and a spherical aberration pattern.
  • FIG. 11 is a diagram showing an example of a beam shape of laser light modulated by a trefoil aberration pattern.
  • FIG. 12 is a diagram illustrating an example of a focused state of laser light and an example of damage caused by light leakage of laser light.
  • FIG. 13 is a diagram showing a first example of a cut surface of a target object for each laser processing condition.
  • FIG. 14 is a diagram showing a first example of a cut surface of a target object for each laser processing condition.
  • FIG. 15 is a diagram showing the relationship between the trefoil aberration intensity and the respective widths of the modified region and crack.
  • FIG. 16 is a diagram showing a second example of the cut surface of the object for each laser processing condition.
  • FIG. 17 is a diagram showing a second example of the cut surface of the object for each laser processing condition.
  • FIG. 18 is a diagram showing the relationship between the trefoil aberration intensity and the angle at which the crack is inclined.
  • FIG. 19 is a diagram showing the relationship between the trefoil aberration intensity and the angle at which the crack is inclined.
  • FIG. 20 is a diagram showing an object to which the first example of the laser processing method is applied.
  • FIG. 21 is a diagram showing one step of the first example of the laser processing method.
  • FIG. 22 is a diagram illustrating an example of a cut surface of an object subjected to light damage suppression processing.
  • FIG. 23 is a diagram showing an object to which the second example of the laser processing method is applied.
  • FIG. 24 is a diagram showing one step of the second example of the laser processing method.
  • the laser processing device 1 includes a support section 2, an irradiation section 3, drive sections 4 and 5, and a control section 6.
  • the laser processing apparatus 1 forms a modified region 12 on the object 11 by irradiating the object 11 with a laser beam L.
  • the support section 2 supports the object 11 by holding a film attached to the object 11, for example.
  • the support part 2 is movable in each of the X direction and the Y direction, and is rotatable about an axis parallel to the Z direction as a rotation axis.
  • the X direction and the Y direction are a first horizontal direction and a second horizontal direction that are perpendicular to each other, and the Z direction is a vertical direction.
  • the irradiation unit 3 focuses a laser beam L that is transparent to the object 11 and irradiates the object 11 with the laser beam L.
  • the irradiation unit 3 is movable in the Z direction.
  • the laser beam L is particularly absorbed in the part corresponding to the focused spot C of the laser beam L, and the laser beam L is absorbed inside the object 11.
  • a modified region 12 is formed.
  • the focused spot C is also referred to as a focused area or a focused point.
  • the modified region 12 is a region whose density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding unmodified region.
  • Examples of the modified region 12 include a melt-treated region, a crack region, a dielectric breakdown region, and a refractive index change region. From the modified region 12, cracks are formed on the incident side of the laser beam L and on the opposite side. Such modified regions 12 and cracks are used to cut the object 11.
  • a plurality of modified spots 12s are lined up in a line along the line A. is formed.
  • One modification spot 12s is formed by irradiation with one pulse of laser light L.
  • One row of modified regions 12 is a collection of a plurality of modified spots 12s arranged in one row. Adjacent modification spots 12s may be connected to each other or separated from each other depending on the relative moving speed of the focused spot C with respect to the object 11 and the repetition frequency of the laser beam L.
  • the drive section 4 supports the support section 2 and drives the support section 2.
  • the drive unit 4 moves the support unit 2 in each of the X direction and the Y direction, and rotates the support unit 2 using an axis parallel to the Z direction as the rotation axis.
  • the drive section 5 supports the irradiation section 3 and drives the irradiation section 3.
  • the drive section 5 moves the irradiation section 3 in the Z direction.
  • the drive unit 4 rotates the support unit 2 so that the line A is parallel to the X direction, and the drive unit 4 rotates the support unit so that the focused spot C is located on the line A.
  • the drive unit 5 moves the irradiation unit 3 in the Z direction so that the focused spot C is located inside the object 11, and further, the focused spot C is moved relative to the target object 11 along the line A.
  • the drive section 4 moves the support section 2 so as to move the support section 2 as desired.
  • the control unit 6 controls the support unit 2, the irradiation unit 3, and the drive units 4 and 5.
  • the control unit 6 has a processing unit, a memory unit, and an input reception unit (not shown).
  • the processing unit is configured as a computer device including a processor, memory, storage, and a communication device.
  • the processor executes software (programs) loaded into the memory, etc., and controls the reading and writing of data in the memory and storage, as well as communication by the communication device.
  • the memory unit is, for example, a hard disk, and stores various types of data.
  • the input reception unit is an interface unit that displays various types of information and receives input of various types of information from the user.
  • the input reception unit constitutes, for example, a GUI (Graphical User Interface).
  • the irradiation section 3 includes a light source 31, a spatial light modulator 7, a condensing section 33, and a 4f lens unit 34.
  • the light source 31 emits laser light L using, for example, a pulse oscillation method.
  • the spatial light modulator 7 modulates the laser beam L emitted from the light source 31 by displaying a modulation pattern.
  • the condensing unit 33 includes at least one lens, and condenses the laser beam L modulated by the spatial light modulator 7 onto the object 11 .
  • the 4f lens unit 34 transfers the image of the laser beam L on the modulation surface of the spatial light modulator 7 to the entrance pupil surface of the condenser 33 .
  • the light source 31 may be provided outside the irradiation section 3 and the laser light L emitted from the light source 31 may be guided to the irradiation section 3.
  • the irradiation unit 3 may include other optical systems.
  • the irradiation unit 3 may include an optical system (for example, an attenuator, a beam expander, etc.) arranged on the optical path between the light source 31 and the spatial light modulator 7.
  • the 4f lens unit 34 has a pair of lenses 34A and 34B.
  • the pair of lenses 34A and 34B are arranged on the optical path of the laser beam L traveling from the spatial light modulator 7 to the condensing section 33.
  • the pair of lenses 34A and 34B constitute a double-sided telecentric optical system in which the modulation surface 7a of the spatial light modulator 7 and the entrance pupil surface 33a of the condenser 33 are in an imaging relationship.
  • the image of the laser beam L on the modulation surface 7a of the spatial light modulator 7 (the image of the laser beam L modulated in the spatial light modulator 7) is transferred (formed) onto the entrance pupil plane 33a of the condenser 33. image) to be done.
  • f1 and f2 indicate the focal lengths of the lenses 34A and 34B, respectively, and Fs indicates the Fourier plane.
  • the spatial light modulator 7 is a reflective liquid crystal (LCOS) spatial light modulator (SLM).
  • LCOS reflective liquid crystal
  • SLM spatial light modulator
  • a drive 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 are arranged on a semiconductor substrate 71 in this order. It is constructed by laminating layers.
  • the semiconductor substrate 71 is, for example, a silicon substrate.
  • the drive circuit layer 72 constitutes an active matrix circuit on the semiconductor substrate 71.
  • the pixel electrode layer 73 includes a plurality of pixel electrodes 73a arranged in a matrix along the surface of the semiconductor substrate 71.
  • Each pixel electrode 73a is made of, for example, a metal material such as aluminum. A voltage is applied to each pixel electrode 73a by the drive circuit layer 72.
  • the reflective film 74 is, for example, a dielectric multilayer film.
  • the alignment film 75 is provided on the surface of the liquid crystal layer 76 on the reflective film 74 side, and the alignment film 77 is provided on the surface of the liquid crystal layer 76 on the opposite side to the reflective film 74.
  • Each of the alignment films 75 and 77 is made of, for example, a polymeric material such as polyimide, and the contact surface of each of the alignment films 75 and 77 with the liquid crystal layer 76 is subjected to, for example, a rubbing treatment.
  • the alignment films 75 and 77 align liquid crystal molecules 76a included in the liquid crystal layer 76 in a certain direction.
  • the transparent conductive film 78 is provided on the surface of the transparent substrate 79 on the alignment film 77 side, and faces the pixel electrode layer 73 with the liquid crystal layer 76 and the like interposed therebetween.
  • the transparent substrate 79 is, for example, a glass substrate.
  • the transparent conductive film 78 is made of a light-transmissive and conductive material such as ITO, for example.
  • the transparent substrate 79 and the transparent conductive film 78 transmit the laser beam L.
  • the spatial light modulator 7 configured as described above, when a signal indicating a modulation pattern is input from the control unit 6 to the drive circuit layer 72, a voltage corresponding to the signal is applied to each pixel electrode 73a, and each An electric field is formed between the pixel electrode 73a and the transparent conductive film 78.
  • the electric field is formed, in the liquid crystal layer 76, the alignment direction of the liquid crystal molecules 76a changes for each region corresponding to each pixel electrode 73a, and the refractive index changes for each region corresponding to each pixel electrode 73a. This state is the state in which the spatial light modulator 7 displays a modulation pattern.
  • the laser beam L enters the liquid crystal layer 76 from the outside via the transparent substrate 79 and the transparent conductive film 78, is reflected by the reflective film 74, and the laser beam L enters the liquid crystal layer 76 from the outside through the transparent substrate 79 and the transparent conductive film 78.
  • the intensity, amplitude, phase, polarization, etc. of the laser beam L are modulated according to the modulation pattern displayed on the liquid crystal layer 76.
  • the modulation surface 7a shown in FIG. 3 corresponds to the liquid crystal layer 76.
  • the control unit 6 can cause the spatial light modulator 7 to display a modulation pattern including a trefoil aberration pattern.
  • FIG. 5 is a diagram showing an example of a trefoil aberration pattern.
  • Trefoil aberration is one of Zernike's third-order aberrations. Note that spherical aberration and astigmatism are included in Zernike's second-order aberration, and coma aberration and trefoil aberration are included in Zernike's third-order aberration.
  • the laser beam L modulated by the spatial light modulator 7 displaying the trefoil aberration pattern is focused by the condenser 33, the laser beam L becomes a condensed spot, as shown in FIG. 6(a). It is most narrowed down in C.
  • the beam shape 9 of the laser beam L at the condensed spot C i.e., a surface that is perpendicular to the optical axis of the laser beam L (dotted chain line shown in FIG. 6(a)) and includes the condensed spot C.
  • FIG. 92 and the third extending portion 93 and has the highest strength at the center portion 90.
  • each of the first extending portion 91, the second extending portion 92, and the third extending portion 93 becomes smaller as the distance from the center portion 90 increases.
  • the strength of each of the existing portion 92 and the third extending portion 93 decreases as the distance from the center portion 90 increases.
  • the beam shape 9 of the laser beam L is like a triangle with each side curved inward.
  • the modulation pattern including a trefoil aberration pattern includes not only a modulation pattern including only a trefoil aberration pattern, but also a modulation pattern including a trefoil aberration pattern and other patterns. Even when the modulation pattern includes a pattern other than the trefoil aberration pattern, when the laser beam L modulated by the spatial light modulator 7 displaying the modulation pattern including the trefoil aberration pattern is condensed by the condenser 33. , the beam shape 9 of the laser beam L at the focused spot C includes a center portion 90 and a first extending portion 91, a second extending portion 92, and a third extending portion 93 extending radially from the center portion 90.
  • the beam shape has the highest intensity at the center portion 90.
  • the beam shape 9 of the laser light L at each focused spot C is determined by the center portion 90 and the first extending portions 91, second extending portions 92, and third extending portions extending radially from the center portion 90.
  • the beam shape includes the existing portion 93 and has the highest strength at the center portion 90.
  • FIG. 7 is a diagram showing an example of the beam shape of the laser light L for each trefoil aberration intensity.
  • the absolute value of the trefoil aberration strength indicates the strength of the trefoil aberration, and the larger the absolute value of the trefoil aberration strength, the stronger the trefoil aberration (therefore, "the trefoil aberration strength is strong" means that the absolute value of the trefoil aberration strength is large) (meaning).
  • the positive or negative sign of the trefoil aberration intensity indicates the direction of the trefoil aberration, and the direction of the trefoil aberration differs by 180 degrees between the trefoil aberration having a positive sign and the trefoil aberration having a negative sign.
  • FIG. 7 shows a camera image taken by a camera as the beam shape of the laser light L.
  • the beam shape 9 of the laser beam L at the focused spot C is The beam shape includes the extending portion 91, the second extending portion 92, and the third extending portion 93 and has the highest strength at the center portion 90 (see (b) of FIG. 6).
  • the beam shape of the laser light L at the -20 ⁇ m position and the beam shape of the laser light L at the +20 ⁇ m position also have the same shape and direction as the beam shape 9 of the laser light L at the focused spot C. becomes.
  • the beam shape 9 of the laser light L at the focused spot C is oriented to the opposite side from the beam shape of the laser light L at the -20 ⁇ m position and the beam shape of the laser light L at the +20 ⁇ m position.
  • the "-20 ⁇ m position” is a position 20 ⁇ m away from the condensing spot C toward the condensing unit 33
  • the "+20 ⁇ m position” is 20 ⁇ m away from the condensing spot C on the side opposite to the condensing unit 33. It is a remote location.
  • FIG. 8 is a diagram showing an example of the beam shape of the laser light L modulated by the trefoil aberration pattern.
  • FIG. 9 is a diagram showing an example of a beam shape of laser light L modulated by a trefoil aberration pattern and an astigmatism pattern (that is, a modulation pattern in which they are superimposed).
  • FIG. 10 is a diagram showing an example of a beam shape of laser light L modulated by a trefoil aberration pattern, an astigmatism pattern, and a spherical aberration pattern (that is, a modulation pattern in which they are superimposed).
  • 8, 9, and 10 show a simulation image obtained by simulation and a camera image captured by a camera as the beam shape of the laser light L.
  • the trefoil aberration intensity of the trefoil aberration pattern is -0.6.
  • the beam shape 9 of the laser beam L at the focused spot C is The beam shape includes the first extending portion 91, the second extending portion 92, and the third extending portion 93 and has the highest strength at the center portion 90 (see (b) of FIG. 6).
  • the beam shape of the laser light L at the -20 ⁇ m position and the beam shape of the laser light L at the +20 ⁇ m position also have the same shape and direction as the beam shape 9 of the laser light L at the focused spot C. becomes.
  • the beam shape 9 of the laser light L at the focused spot C is oriented to the opposite side from the beam shape of the laser light L at the -20 ⁇ m position and the beam shape of the laser light L at the +20 ⁇ m position.
  • you include not only the high-intensity parts but also the low-intensity parts you can see that they are facing the same side as the beam shape.
  • FIG. 11 is a diagram showing an example of the beam shape of the laser light L modulated by the trefoil aberration pattern.
  • the trefoil aberration intensity of the trefoil aberration pattern is -0.5.
  • the beam shape of the laser light L at the -100 ⁇ m position and the beam shape of the laser light L at the +100 ⁇ m position are on the opposite side to the beam shape 9 of the laser light L at the focused spot C.
  • the beam shape is oriented.
  • the "-100 ⁇ m position” is a position 100 ⁇ m away from the condensing spot C toward the condensing part 33, and the "+100 ⁇ m position” is 100 ⁇ m away from the condensing spot C on the side opposite to the condensing part 33. It is a remote location.
  • the beam shape of the laser light L at the -20 ⁇ m position and the beam shape of the laser light L at the +20 ⁇ m position are similar to the beam shape 9 of the laser light L at the focused spot C. and a beam shape having a direction (see FIGS. 7, 8, 9, and 10).
  • the beam shape of the laser light L at the ⁇ 20 ⁇ m position clearly shows the beam shape 9 of the laser light L at the focused spot C compared to the beam shape of the laser light L at the +20 ⁇ m position.
  • a metal film 8 is formed on the second surface 11b of the object 11, which is a silicon wafer, and the first surface 11a of the object 11 is used as the incident surface of the laser beam L.
  • the laser beam L is irradiated onto the object 11 by aligning the focused spot C with a position 20 to 30 ⁇ m from the second surface 11b and inside the object 11, the laser beam L is modulated by a modulation pattern including a trefoil aberration pattern.
  • damage having the same shape and direction as the beam shape 9 of the laser beam L at the focused spot C occurs on the metal, as shown in FIG.
  • the film 8 is formed. Therefore, in order to estimate the beam shape 9 of the laser light L at the focused spot C when the laser light L modulated by the modulation pattern including the trefoil aberration pattern is focused, it is necessary to 8 and observe the damage.
  • 13 and 14 are diagrams showing first examples of cut surfaces of the object 11 for each laser processing condition.
  • 13 and 14 "Two rows of modified regions aligned in the thickness direction of the silicon wafer are formed inside the object 11, which is a silicon wafer, along line A, and then the object 11 is A cut surface of the object 11 when it is cut along line A by expanding is shown.
  • condition A is that the condensed spot C is relatively moved in the "direction indicated by the arrow on line A" (rightward in FIG. 13, leftward in FIG. 14);
  • the beam shape 9 of the laser beam L at the focused spot C is such that (1) the center portion 90 and the first extension portion 91 are located on the line A, and the first side with respect to the line A (FIG. 13
  • the second extending portion 92 is located on the upper side in FIG. 14, and the lower side in FIG. and (2) the first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along the line A, and the second extension part 91 is located on the rear side in the direction.
  • the laser processing conditions are such that the portion 92 and the third extension portion 93 are located.
  • Extension B is such that the focused spot C is relatively moved in the "direction indicated by the arrow on line A" (leftward in FIG. 13, rightward in FIG. 14), and at that time, the focused spot
  • the beam shape 9 of the laser beam L at C is as follows: 13, the second extending portion 92 is located on the lower side) and the third extending portion 93 is located on the first side (lower side in FIG. 13, upper side in FIG. and (3) "the first extension part 91 is located on the rear side in the direction in which the focused spot C moves relatively along the line A, and the second extension part 92 and the third extension part are located on the front side in the direction These are the laser processing conditions in which the extension portion 93 is positioned.
  • “Standard” in the "Condition A” column is a laser processing condition that differs from “Condition A” only in that the modulation pattern does not include a trefoil aberration pattern.
  • “Standard” in the “Condition B” stage is a laser processing condition that differs from “Condition B” only in that the modulation pattern does not include a trefoil aberration pattern.
  • a modified region 12 is formed in the object 11 along a line A, and the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of the line A are
  • the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of the line A are
  • a first The extension part 91 is located
  • the second extension part 92 is located on one side with respect to line A
  • the third extension part 93 is located on the other side with respect to line A (FIG. 13).
  • a modulation pattern including a trefoil aberration pattern may be displayed on the spatial light modulator 7.
  • the width of the crack in the incident direction of the laser beam L is small because the black streaks extending in the left and right direction are modified in two rows. This can be seen from the fact that it is formed between the dark areas (black band-shaped areas extending in the left-right direction).
  • the reason for this is that when cutting the object 11 by expanding is performed in a state where the cracks extending from each modified region are not connected between the two rows of modified regions when two rows of modified regions are formed. This is because black streaks extending in the left-right direction may be formed.
  • the laser beam L when forming the modified region 12 in the object 11 along the line A and also forming the crack 13 in the object 11 along the first surface P1, the laser beam L When reducing not only the width of the crack 13 in the incident direction of the laser beam L but also the width of the modified region 12 in the incident direction of the laser beam L and suppressing the meandering of the crack 13 with respect to the line A,
  • the first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along the line, and the second extension part 92 and the third extension part 93 are located on the rear side in the direction.
  • a modulation pattern including a trefoil aberration pattern may be displayed on the spatial light modulator 7.
  • twist hackle the amount of twist hackle (referred to as twist hackle) was decreased in "Condition A” compared to "Standard” and "Condition B".
  • the focused spot C is relatively moved along the first line.
  • the direction in which the focused spot C is moved is different from the direction in which the focused spot C is relatively moved along the second line
  • the focused spot C is relatively moved along each of the first line and the second line.
  • a trefoil aberration pattern is formed in the spatial light modulator 7 so that the first extension part 91 is located on the front side in the direction, and the second extension part 92 and the third extension part 93 are located on the rear side in the direction. What is necessary is to switch the direction of the included modulation pattern.
  • the trefoil with the first trefoil aberration strength is displayed on the spatial light modulator 7 and at least one of the widths is a second width smaller than the first width, the second trefoil aberration intensity is stronger than the first trefoil aberration intensity.
  • the widths of each of the modified region 12 and the crack 13 in the incident direction of the laser beam L are smaller at the second trefoil aberration intensity than at the first trefoil aberration intensity.
  • FIGS. 16 and 17 are diagrams showing second examples of cut surfaces of the object 11 for each laser processing condition. 16 and 17, "Two rows of modified regions lined up in the thickness direction of the silicon wafer are formed inside the object 11, which is a silicon wafer, along line A, and then the object 11 is A cut surface of the object 11 when it is cut along line A by expanding is shown.
  • Extension D is such that the focused spot C is relatively moved in the "direction indicated by the arrow on line A" (leftward in FIG. 16, rightward in FIG. 17), and at that time, the focused spot
  • the beam shape 9 of the laser beam L at C is defined as (5) "The center part 90 is located on line A, and the first part is located on the second side with respect to line A (upper side in FIG. 16, lower side in FIG. A state in which the extension part 91 is located and the second extension part 92 and the third extension part 93 are located on the first side (lower side in FIG. 16, upper side in FIG. 17) with respect to line A. These are laser processing conditions.
  • “Standard” in the "Condition C” column is a laser processing condition that differs from “Condition C” only in that the modulation pattern does not include a trefoil aberration pattern.
  • “Standard” in the “Condition D” stage is a laser processing condition that differs from “Condition D” only in that the modulation pattern does not include a trefoil aberration pattern.
  • a modified region 12 is formed in the object 11 along a line A, and the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of the line A are
  • the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of the line A are
  • the area on the opposite side to the incident side of the laser beam L is
  • the second surface P2 is inclined so as to be located on one side (the left side in FIG.
  • the Trefoil aberration pattern is such that the first extending part 91 is located on the left side) and the second extending part 92 and the third extending part 93 are located on the other side (right side in FIG. 18) with respect to the line A. What is necessary is to display a modulation pattern including the following on the spatial light modulator 7.
  • a modified region 12 is formed in the object 11 along line A, and the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of line A are When forming a crack 13 in the object 11 along the second surface P2 that is inclined with respect to the first surface P1 that is parallel to both directions (X direction), the area on the opposite side to the incident side of the laser beam L is When the second surface P2 is inclined so as to be located on the other side (the right side in FIG.
  • the Trefoil aberration pattern is such that the first extending part 91 is located on the right side) and the second extending part 92 and the third extending part 93 are located on one side (left side in FIG. 19) with respect to the line A. What is necessary is to display a modulation pattern including the following on the spatial light modulator 7.
  • the focused spot C is relatively moved along each of the first line and the second line set on the object 11 as the line A.
  • the first extension portion 91 is placed on one side with respect to each of the first line and the second line.
  • a trefoil aberration pattern is formed such that What is necessary is to switch the direction of the included modulation pattern.
  • the angle between the first surface P1 and the second surface P2 (that is, the acute angle formed by the first surface P1 and the second surface P2) is
  • a modulation pattern including a trefoil aberration pattern with the first trefoil aberration intensity is displayed on the spatial light modulator 7, and when the angle is set as a second angle larger than the first angle, the first trefoil aberration intensity is
  • the spatial light modulator 7 may display a modulation pattern including a trefoil aberration pattern having a second trefoil aberration intensity stronger than the trefoil aberration intensity.
  • FIG. 20 is a diagram showing an object 11 to which the first example of the laser processing method is applied.
  • the object 11 is a semiconductor wafer having a first surface 11a and a second surface 11b.
  • the object 11 includes a silicon wafer and a plurality of functional elements (not shown) formed on the first surface 11a side of the silicon wafer.
  • the plurality of functional elements are arranged in a matrix along the first surface 11a with a notch 11c formed in the object 11 as a reference.
  • Each functional element is, for example, a light receiving element such as a photodiode, a light emitting element such as a laser diode, a circuit element such as a memory, and the like.
  • Each functional element may be configured three-dimensionally by stacking a plurality of layers. Note that an orientation flat may be formed on the object 11 instead of the notch 11c.
  • a first example of the laser processing method is carried out in the laser processing apparatus 1 described above.
  • the object 11 shown in FIG. 20 is cut into functional elements along each of a plurality of processing surfaces P10 extending in a grid pattern.
  • Each processed surface P10 is a plane perpendicular to the first surface 11a and the second surface 11b.
  • two rows of modified regions 12 aligned in the thickness direction of the object 11 are formed inside the object 11 along the line A.
  • a modified region 12 is formed in the object 11 along a line A extending within the processing surface P10, and a crack 13 is formed in the object 11 along the first surface P1.
  • the widths of the modified region 12 and the crack 13 in the direction of incidence of the laser beam L are made small, and the crack 13 is made small with respect to the line A. I want to suppress meandering.
  • the first extension part 91 is located on the line A
  • the second extension part 92 is located on one side with respect to the line A
  • the second extension part 92 is located on the other side with respect to the line A.
  • the first extending part 91 is located in the front side in the direction in which the focused spot C moves relatively along the line A
  • the control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern so that the second extension part 92 and the third extension part 93 are located on the side.
  • the control unit 6 changes the modulation pattern including the trefoil aberration pattern with stronger trefoil aberration intensity to the spatial light. Displayed on the modulator 7.
  • the control unit 6 controls the support unit 2 so that the focused spot C moves relatively along the line A.
  • the drive section 4 is caused to drive.
  • the laser beam L may be incident on the first surface 11a side of the object 11, or the laser beam L may be incident on the second surface 11b side of the object 11. You can. Furthermore, one row of modified regions 12 may be formed inside the object 11 along line A, or three or more rows of modified regions 12 lined up in the thickness direction of object 11 may be formed along line A. It may be formed inside the object 11. When a plurality of rows of modified regions 12 arranged in the thickness direction of the object 11 are formed inside the object 11 along the line A, the laser beam L is spatially modulated so as to have a plurality of focused spots C.
  • a plurality of rows of modified regions 12 are created inside the object 11 along the line A by one scan of the laser beam L (relative movement of the laser beam L along the line A). may be formed.
  • a dicing tape may be attached to the first surface 11a or the second surface 11b opposite to the surface on which the laser beam L is incident, or the first surface on which the laser beam L is incident.
  • a dicing tape that is transparent to the laser beam L may be attached to the first surface 11a or the second surface 11b.
  • the second surface 11b of the object 11 may be ground to make the object 11 thinner. At that time, the modified region 12 formed in the object 11 may be removed.
  • a modified region 12 (hereinafter referred to as "first modified region") near the surface on the emission side of the laser beam L (second surface 11b in the example shown in FIG. 21)
  • the first modified region is formed so that the cracks 13 do not reach the surface on the emission side of the laser beam L from the first modified region, and the first modified region and the surface on the incidence side of the laser beam L are formed.
  • the first surface 11a when forming the modified region 12 (hereinafter referred to as "second modified region"), the first modified region and the second The cracks 13 may be connected to the modified region, and the cracks 13 may be made to reach the surface on the emission side of the laser beam L from the first modified region (hereinafter referred to as "light leakage damage suppression processing").
  • the first extending portion 91 is located on the line A
  • the second extending portion 92 is located on one side with respect to the line A
  • the first extending portion 91 is located on the line A.
  • the control unit 6 causes the spatial light modulator 7 to display a modulation pattern including a trefoil aberration pattern so that the third extension part 93 is located on the other side with respect to A, thereby forming a second modified region.
  • the control unit 6 transmits a modulation pattern that does not include a trefoil aberration pattern (or a modulation pattern that includes a trefoil aberration pattern having a weaker trefoil aberration intensity than when forming the first modified region) to the spatial light modulator 7.
  • the first extending portion 91 is located on line A
  • the second extending portion 92 is located on one side with respect to line A
  • the first extending part 91 is located in front of the direction in which the focused spot C moves relatively along the line A
  • the third extending part 93 is located on the other side.
  • the above findings are applicable when forming "at least one row of first modified regions" and "at least one row of second modified regions” inside the target object 11 along line A in the thickness direction of the target object 11. Applicable to In this case, the number of rows of the first modified region and the number of rows of the second modified region may be the same or different.
  • the laser beam L is modulated by the spatial light modulator 7 so as to have a plurality of focused spots C, and by one scan of the laser beam L, multiple rows of the first modified region are lined up. It may be formed inside the object 11 along A. Also in this case, the first extension part 91 is located on line A, the second extension part 92 is located on one side with respect to line A, and the third extension part 92 is located on the other side with respect to line A.
  • the control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern so that the existing portion 93 is located.
  • the first extending part 91 is located on line A
  • the second extending part 92 is located on one side with respect to line A
  • the third extending part 93 is located on the other side with respect to line A.
  • the first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along line A
  • the control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern so that the third extension portion 93 is located.
  • a plurality of rows of first modified regions may be formed inside the object 11 along the line A by each scan of the laser beam L a plurality of times. Note that even when a plurality of rows of first modified regions are formed inside the object 11 along the line A by one scan of the laser beam L, a plurality of rows of first modified regions are formed by each of the plurality of scans of the laser beam L. Even when each of the first modified regions in the rows is formed inside the object 11 along the line A, it is preferable that the cracks extending from each of the first modified regions in the plurality of rows do not connect to each other.
  • a plurality of focused spots C are formed in order to increase the takt time. Even if the laser beam L is modulated by the spatial light modulator 7 so that a plurality of rows of second modified regions are formed inside the object 11 along the line A by one scan of the laser beam L. good.
  • the plural rows of second modified regions are formed by each of the plurality of scans of the laser beam L.
  • Each of the second modified regions may be formed inside the object 11 along the line A.
  • FIG. 22 is a diagram illustrating an example of a cut surface of the object 11 obtained by processing to suppress damage caused by light leakage.
  • the example of the cut plane shown in FIGS. 22(a) and (b) shows "three rows of first modified regions” and "three rows of second modified regions” arranged in the thickness direction of the object 11. This is obtained by forming it inside the object 11 along line A.
  • three rows of first modified regions are formed inside the object 11 along the line A by one scan of the laser beam L, and then, Three rows of second modified regions were formed inside the object 11 along the line A by one scan of the laser beam L.
  • FIG. 22 is a diagram illustrating an example of a cut surface of the object 11 obtained by processing to suppress damage caused by light leakage.
  • the example of the cut plane shown in FIGS. 22(a) and (b) shows "three rows of first modified regions" and "three rows of second modified regions” arranged in the thickness direction of the object 11. This is obtained by forming it inside the object 11 along line A.
  • FIG. 22(a) when forming three rows of first modified regions, a modulation pattern that does not include a trefoil aberration pattern is displayed on the spatial light modulator 7.
  • the first extending portion 91 is located on line A, and the second extending portion is located on one side with respect to line A.
  • 92 and the third extension part 93 is located on the other side with respect to the line A, and the first extension part 93 is located on the front side in the direction in which the focused spot C moves relatively along the line A.
  • a modulation pattern including a trefoil aberration pattern was displayed on the spatial light modulator 7 such that the existing portion 91 was located and the second extending portion 92 and the third extending portion 93 were located on the rear side in this direction.
  • twist hackles occurred in the region where the three rows of first modified regions were formed, and the way the cracks grew was not stable.
  • FIG. 22(b) the occurrence of twist hackles was suppressed in the region where the three rows of first modified regions were formed, and the growth of cracks was also stabilized.
  • FIGS. 23A and 23B are diagrams showing an object 100 to which the second example of the laser processing method is applied.
  • the object 100 includes an object 11 and an object 11R that is a separate member from the object 11.
  • Each target object 11, 11R is, for example, a silicon wafer.
  • a device layer 110 including a plurality of functional elements (not shown) is formed on the second surface 11b of the object 11.
  • a device layer 110R including a plurality of functional elements (not shown) is formed on one surface of the object 11R.
  • the device layer 110 and the device layer 110R are bonded to each other.
  • a second example of the laser processing method is carried out in the laser processing apparatus 1 described above.
  • the object 11 shown in FIGS. 23A and 23B is cut along each of the processing surface P11, the processing surface P12, and the plurality of processing surfaces P13, and The outer edge portion of the object 11 is removed (trimming process).
  • the processed surface P11 is a cylindrical surface having a center line parallel to the Z direction.
  • the processed surface P12 is a truncated conical tapered surface that expands from the end of the processed surface P11 on the device layer 110 side toward the outer edge of the device layer 110R.
  • the plurality of processing surfaces P13 are planes extending from the processing surface P11 to the outer edge of the object 11.
  • the line A extends circumferentially within the processing surface P12, but when the line A is a curved line, the extending direction of the line A is defined as means the tangential direction.
  • a modified region 12 is formed in the object 11 along the line A extending within the processing surface P12, and a crack 13 is formed in the object 11 along the second surface P2.
  • the second surface P2 is inclined such that the region on the opposite side to the incident side of the laser beam L is located on the outside in the direction perpendicular to the first surface P1 (Y direction). ing.
  • the first extension part 91 is located outside the line A, and the second extension part 92 and the third extension part 93 are located inside the line A.
  • the control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern.
  • the control unit 6 applies a modulation pattern including a trefoil aberration pattern with a stronger trefoil aberration intensity to the spatial light modulator 7. Display.
  • the control unit 6 controls the support unit 2 so that the focused spot C moves relatively along the line A.
  • the drive section 4 is caused to drive. Subsequently, a plurality of modified regions 12 arranged in the thickness direction of the object 11 are formed along each of the processed surface P11 and the plurality of processed surfaces P13. After the above steps are performed, the outer edge portion of the object 11 is removed, and the first surface 11a of the object 11 is polished to remove the portion where the processed surface P11 was set. [Action and effect]
  • the beam shape 9 of the laser light L at the focused spot C has a center portion 90 and a first extension extending radially from the center portion 90.
  • the focused spot C is located along the line A set on the object 11, including the existing part 91, the second extending part 92, and the third extending part 93, and having the highest intensity in the central part 90. can be moved relative to each other.
  • the state of at least one of the modified region 12 and the crack 13 formed in the object 11 can be adjusted. Therefore, according to the laser processing apparatus 1, appropriate modified regions 12 and cracks 13 can be formed in the object 11 according to the processing.
  • a modified region 12 is formed in the object 11 along the line A, and a first surface parallel to both the incident direction of the laser beam L and the extending direction of the line A is formed from the modified region 12.
  • the control unit 6 determines that the first extension part 91 is located on the line A and the second extension part is located on one side with respect to the line A.
  • a modulation pattern including a trefoil aberration pattern is displayed on the spatial light modulator 7 such that the third extension part 93 is located on the other side with respect to the line A.
  • the width of the crack 13 in the incident direction of the laser beam L can be made smaller than, for example, when the modulation pattern does not include a trefoil aberration pattern.
  • the control unit 6 is configured such that the first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along the line A, and the second extension part 91 is located on the rear side in the direction in which the focused spot C moves relatively along the line A.
  • a modulation pattern including a trefoil aberration pattern is displayed on the spatial light modulator 7 such that the third extension portion 92 and the third extension portion 93 are located.
  • the control unit 6 moves the focal spot C along the first line and the second line, respectively.
  • Trefoil aberration is created such that the first extension part 91 is located on the front side in the direction in which the light spot C moves relatively, and the second extension part 92 and the third extension part 93 are located on the rear side in the direction. Switch the orientation of modulation patterns including patterns.
  • the first line and The first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along each of the second lines, and the second extension part 92 and the third extension part are on the rear side in the direction. 93 can be easily and reliably realized.
  • the controller 6 sets a trefoil aberration pattern with a first trefoil aberration intensity.
  • the spatial light modulator 7 displays a modulation pattern including a modulation pattern, and when at least one of the widths is a second width smaller than the first width, a trefoil aberration with a second trefoil aberration intensity stronger than the first trefoil aberration intensity.
  • a modulation pattern including the pattern is displayed on the spatial light modulator 7.
  • a modified region 12 is formed in the object 11 along the line A, and a first surface parallel to both the incident direction of the laser beam L and the extending direction of the line A is formed from the modified region 12.
  • the region opposite to the incident side of the laser beam L is on one side in the direction perpendicular to the first surface P1.
  • the second surface P2 is inclined so as to be located at A modulation pattern including a trefoil aberration pattern is displayed on the spatial light modulator 7 so that the second extension part 92 and the third extension part 93 are located.
  • the cracks 13 extending from the modified region 12 can be inclined to a desired side.
  • the control unit 6 controls one direction for each of the first line and the second line. Trefoil aberration such that the first extending part 91 is located on the side of Switch the orientation of modulation patterns including patterns.
  • the first line and A first extending portion 91 is located on one side with respect to each of the second lines, and a second extending portion 92 and a third extending portion are located on the other side with respect to each of the first line and the second line. 93 can be easily and reliably realized.
  • the control unit 6 when the control unit 6 sets the angle between the first surface P1 and the second surface P2 as the first angle, the control unit 6 spatially modulates the modulation pattern including the trefoil aberration pattern with the first trefoil aberration intensity.
  • a modulation pattern including a trefoil aberration pattern with a second trefoil aberration intensity stronger than the first trefoil aberration intensity is displayed on the spatial light. Displayed on the modulator 7. Thereby, the angle at which the cracks 13 extending from the modified region 12 are inclined can be set to an appropriate angle depending on the processing.
  • the spatial light modulator 7 is not limited to a reflective type, but may be a transmissive type.
  • the optical system that transfers the image of the laser beam L on the modulation surface 7a of the spatial light modulator 7 to the entrance pupil plane 33a of the condenser 33 is limited to the 4f lens unit 34 having a pair of lenses 34A and 34B.
  • the first lens system for example, a cemented lens, three or more lenses, etc.
  • the second lens system for example, a cemented lens, three or more lenses, etc.
  • the drive section 4 drives the support section 2, and the drive section 5 drives the light collecting section 33 by driving the irradiation section 3,
  • the drive section of the present disclosure The section is not limited to such.
  • the drive unit 4 may move the support unit 2 in each of the Z direction, the X direction, and the Y direction, and rotate the support unit 2 using an axis parallel to the Z direction as the rotation axis.
  • the drive section 5 may move the light condensing section 33 in each of the Z direction, the X direction, and the Y direction, and may move the light condensing section 33 with an axis parallel to the Z direction as the center line.
  • the drive unit of the present disclosure may be any drive unit that drives at least one of the support unit and the light condensing unit.
  • control unit 6 controls the support unit 2, the irradiation unit 3, and the drive units 4 and 5, but the control unit of the present disclosure is not limited to such a unit.
  • the control unit of the present disclosure may be any unit as long as it controls at least the spatial light modulator and the drive unit.
  • the Trefoil is arranged such that the first extending portion 91 is located on one side with respect to line A, and the second extending portion 92 and third extending portion 93 are located on the other side with respect to line A.
  • the laser processing method of displaying a modulation pattern including an aberration pattern on the spatial light modulator 7 can also be used when cutting a wafer into a plurality of square pyramid-shaped chips, cutting out a plurality of truncated cone-shaped wafers from a wafer, etc. It is valid.
  • SYMBOLS 1 Laser processing device, 2... Support part, 4, 5... Drive part, 6... Control part, 7... Spatial light modulator, 9... Beam shape, 11... Target object, 12... Modified region, 13... Crack, 31...Light source, 33...Condensing part, 90...Central part, 91...First extension part, 92...Second extension part, 93...Third extension part, A...Line, C...Condensing spot, L ...Laser light, P1...first surface, P2...second surface.

Abstract

This laser processing device comprises a support unit for supporting a target object, a light source for emitting laser light, a spatial optical modulator for modulating the laser light by displaying a modulation pattern, a condensing unit for condensing the laser light onto the target object, a drive unit for driving at least one of the support unit and the condensing unit, and a control unit. The control unit causes the spatial optical modulator to display a modulation pattern that includes a trefoil aberration pattern such that a beam shape of the laser light at a focal spot includes a central portion and a first extended portion, a second extended portion and a third extended portion that extend in a radial pattern from the central portion, and such that the highest intensity in the beam shape central is in the central portion. The control unit causes the drive unit to drive the at least one of the support unit and the condensing unit such that the focal spot moves relatively along a line.

Description

レーザ加工装置及びレーザ加工方法Laser processing equipment and laser processing method
　本開示は、レーザ加工装置及びレーザ加工方法に関する。 The present disclosure relates to a laser processing device and a laser processing method.
　対象物を支持する支持部と、レーザ光を出射する光源と、光源から出射されたレーザ光を変調する空間光変調器と、空間光変調器によって変調されたレーザ光を対象物に集光する集光部と、空間光変調器におけるレーザ光の像を集光部の入射瞳面に転像する転像部と、を備えるレーザ加工装置が知られている（例えば、特許文献１参照）。 A support part that supports a target object, a light source that emits laser light, a spatial light modulator that modulates the laser light emitted from the light source, and a laser light modulated by the spatial light modulator that focuses the laser light on the target object. 2. Description of the Related Art A laser processing apparatus is known that includes a condensing section and an image transfer section that transfers an image of a laser beam in a spatial light modulator onto an entrance pupil plane of the condensing section (see, for example, Patent Document 1).
特開２０１１－５１０１１号公報Japanese Patent Application Publication No. 2011-51011
　上述したようなレーザ加工装置は、改質領域及び亀裂を対象物に形成することができる。そのような改質領域及び亀裂の形成は、対象物を複数のチップに分割するのダイシング加工、対象物から不要部分を除去するトリミング加工等、様々な加工に応用可能である。 A laser processing device such as that described above can form modified regions and cracks in a target object. Formation of such modified regions and cracks can be applied to various processes, such as dicing to divide an object into a plurality of chips, trimming to remove unnecessary parts from the object, and the like.
　本開示は、加工に応じて適切な改質領域及び亀裂を対象物に形成することができるレーザ加工装置及びレーザ加工方法を提供することを目的とする。 An object of the present disclosure is to provide a laser processing device and a laser processing method that can form appropriate modified regions and cracks in a target object depending on the processing.
　本開示の一側面のレーザ加工装置は、［１］「対象物を支持する支持部と、レーザ光を出射する光源と、変調パターンを表示することで、前記光源から出射された前記レーザ光を変調する空間光変調器と、前記空間光変調器によって変調された前記レーザ光を前記対象物に集光する集光部と、前記支持部及び前記集光部の少なくとも一方を駆動する駆動部と、少なくとも前記空間光変調器及び前記駆動部を制御する制御部と、を備え、前記制御部は、前記レーザ光の集光スポットにおける前記レーザ光のビーム形状が、中心部並びに前記中心部から放射状に延在する第１延在部、第２延在部及び第３延在部を含み且つ前記中心部において最も高い強度を有するビーム形状となるように、トレフォイル収差パターンを含む変調パターンを前記空間光変調器に表示させ、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させた状態で、前記対象物に設定されたラインに沿って前記集光スポットが相対的に移動するように、前記支持部及び前記集光部の少なくとも一方を前記駆動部に駆動させる、レーザ加工装置」である。 A laser processing apparatus according to an aspect of the present disclosure includes [1] "a support section that supports a target object, a light source that emits laser light, and a modulation pattern that displays the laser beam emitted from the light source." a spatial light modulator that modulates the laser beam, a focusing section that focuses the laser beam modulated by the spatial light modulator on the object, and a driving section that drives at least one of the support section and the focusing section. , a control unit that controls at least the spatial light modulator and the drive unit, and the control unit is configured such that the beam shape of the laser beam at the focused spot of the laser beam is radial from the center and the center. A modulation pattern including a trefoil aberration pattern is formed in the space so that the beam shape includes a first extension part, a second extension part, and a third extension part extending in the space and has the highest intensity in the center part. The focused spot moves relatively along a line set on the object while the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator. A laser processing apparatus in which at least one of the supporting section and the light condensing section is driven by the driving section.
　上記［１］に記載のレーザ加工装置では、集光スポットにおけるレーザ光のビーム形状が、中心部並びに中心部から放射状に延在する第１延在部、第２延在部及び第３延在部を含み且つ中心部において最も高い強度を有する状態で、当該集光スポットが、対象物に設定されたラインに沿って相対的に移動させられる。このとき、ラインに対するビーム形状の向き等を調整することで、対象物に形成される改質領域及び亀裂の少なくとも一方の状態を調整することができる。よって、上記［１］に記載のレーザ加工装置によれば、加工に応じて適切な改質領域及び亀裂を対象物に形成することができる。 In the laser processing apparatus according to [1] above, the beam shape of the laser beam at the focused spot is formed into a central portion, a first extending portion, a second extending portion, and a third extending portion extending radially from the central portion. The focused spot is relatively moved along a line set on the object, with the focus having the highest intensity at the center. At this time, by adjusting the direction of the beam shape with respect to the line, etc., the state of at least one of the modified region and the cracks formed in the object can be adjusted. Therefore, according to the laser processing apparatus described in [1] above, appropriate modified regions and cracks can be formed in the object according to the processing.
　本開示の一側面のレーザ加工装置は、［２］「前記ラインに沿って前記対象物に改質領域を形成すると共に、前記改質領域から前記レーザ光の入射方向及び前記ラインの延在方向の両方向に平行な第１面に沿って前記対象物に亀裂を形成する場合には、前記制御部は、前記ライン上に前記第１延在部が位置し且つ前記ラインに対して一方の側に前記第２延在部が位置し且つ前記ラインに対して他方の側に前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、上記［１］に記載のレーザ加工装置」であってもよい。当該［２］に記載のレーザ加工装置によれば、例えば変調パターンがトレフォイル収差パターンを含まない場合に比べ、レーザ光の入射方向における亀裂の幅を小さくすることができる。 A laser processing apparatus according to one aspect of the present disclosure includes [2] "forming a modified region in the target object along the line, and from the modified region in the incident direction of the laser beam and in the extending direction of the line. When forming a crack in the object along a first surface parallel to both directions of Displaying the modulation pattern including the trefoil aberration pattern on the spatial light modulator such that the second extension part is located at and the third extension part is located on the other side with respect to the line. , the laser processing apparatus described in [1] above. According to the laser processing apparatus described in [2], the width of the crack in the laser beam incident direction can be made smaller than, for example, when the modulation pattern does not include a trefoil aberration pattern.
　本開示の一側面のレーザ加工装置は、［３］「前記制御部は、前記ラインに沿って前記集光スポットが相対的に移動する向きの前側に前記第１延在部が位置し且つ前記向きの後側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、上記［２］に記載のレーザ加工装置」であってもよい。当該［３］に記載のレーザ加工装置によれば、レーザ光の入射方向における亀裂の幅だけでなく、レーザ光の入射方向における改質領域の幅も小さくすることができる。また、ラインに対して亀裂が蛇行するのを確実に抑制することができる。 The laser processing device according to one aspect of the present disclosure may be the laser processing device described in [2] above, [3] "wherein the control unit causes the spatial light modulator to display the modulation pattern including the trefoil aberration pattern such that the first extension portion is located in front of the direction in which the focused spot moves relatively along the line, and the second extension portion and the third extension portion are located in the rear of the direction." According to the laser processing device described in [3], not only the width of the crack in the incident direction of the laser light, but also the width of the modified region in the incident direction of the laser light can be reduced. In addition, it is possible to reliably prevent the crack from meandering along the line.
　本開示の一側面のレーザ加工装置は、［４］「前記ラインとして前記対象物に設定された第１ライン及び第２ラインのそれぞれに沿って前記集光スポットを相対的に移動させる場合において、前記第１ラインに沿って前記集光スポットを相対的に移動させる向きと、前記第２ラインに沿って前記集光スポットを相対的に移動させる向きとが異なるときには、前記制御部は、前記第１ライン及び前記第２ラインのそれぞれに沿って前記集光スポットが相対的に移動する向きの前側に前記第１延在部が位置し且つ前記向きの後側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンの向きを切り替える、上記［３］に記載のレーザ加工装置」であってもよい。当該［４］に記載のレーザ加工装置によれば、第１ラインに沿って集光スポットを相対的に移動させる向きと、第２ラインに沿って集光スポットを相対的に移動させる向きとが異なる場合にも、第１ライン及び第２ラインのそれぞれに沿って集光スポットが相対的に移動する向きの前側に第１延在部が位置し且つ当該向きの後側に第２延在部及び第３延在部が位置する状態を容易に且つ確実に実現することができる。 The laser processing device according to one aspect of the present disclosure includes [4] “In the case where the focused spot is relatively moved along each of a first line and a second line set on the object as the line, When the direction in which the focused spot is relatively moved along the first line is different from the direction in which the focused spot is relatively moved along the second line, the control unit The first extension part is located on the front side in the direction in which the focused spot moves relatively along each of the first line and the second line, and the second extension part and the The laser processing apparatus according to [3] above may change the direction of the modulation pattern including the trefoil aberration pattern so that the third extension portion is located. According to the laser processing apparatus described in [4], the direction in which the focused spot is relatively moved along the first line and the direction in which the focused spot is relatively moved along the second line are different. Even when different, the first extension part is located on the front side in the direction in which the focused spot moves relatively along each of the first line and the second line, and the second extension part is located on the rear side in the direction. The state in which the third extension portion is located can be easily and reliably realized.
　本開示の一側面のレーザ加工装置は、［５］「前記制御部は、前記レーザ光の前記入射方向における前記改質領域及び前記亀裂の少なくとも一方の幅を第１幅とする場合には、第１トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させ、前記少なくとも一方の幅を前記第１幅よりも小さい第２幅とする場合には、前記第１トレフォイル収差強度よりも強い第２トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、上記［２］～［４］のいずれか一つに記載のレーザ加工装置」であってもよい。当該［５］に記載のレーザ加工装置によれば、レーザ光の入射方向における改質領域及び亀裂の少なくとも一方の幅を、加工に応じて適切な幅にすることができる。 The laser processing device according to one aspect of the present disclosure provides [5] “When the control unit sets a width of at least one of the modified region and the crack in the incident direction of the laser beam as a first width, If the modulation pattern including the trefoil aberration pattern having a first trefoil aberration intensity is displayed on the spatial light modulator, and the width of at least one of the patterns is a second width smaller than the first width, The laser processing device according to any one of [2] to [4] above, wherein the modulation pattern including the trefoil aberration pattern having a second trefoil aberration intensity stronger than the trefoil aberration intensity is displayed on the spatial light modulator. ”. According to the laser processing apparatus described in [5], the width of at least one of the modified region and the crack in the incident direction of the laser beam can be set to an appropriate width depending on the processing.
　本開示の一側面のレーザ加工装置は、［６］「前記ラインに沿って前記対象物に改質領域を形成すると共に、前記改質領域から前記レーザ光の入射方向及び前記ラインの延在方向の両方向に平行な第１面に対して傾斜する第２面に沿って前記対象物に亀裂を形成する場合において、前記レーザ光の入射側とは反対側の領域が前記第１面に垂直な方向における一方の側に位置するように前記第２面が傾斜しているときには、前記制御部は、前記ラインに対して前記一方の側に前記第１延在部が位置し且つ前記ラインに対して他方の側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、上記［１］に記載のレーザ加工装置」であってもよい。当該［６］に記載のレーザ加工装置によれば、改質領域から延在する亀裂を所望の側に傾斜させることができる。 The laser processing apparatus according to one aspect of the present disclosure includes [6] "forming a modified region in the object along the line, and from the modified region in the incident direction of the laser beam and in the extending direction of the line. When a crack is formed in the object along a second surface that is inclined with respect to a first surface that is parallel to both directions, a region on the opposite side to the incident side of the laser beam is perpendicular to the first surface. When the second surface is inclined so as to be located on one side in the direction, the control section is configured such that the first extending section is located on the one side with respect to the line and the second surface is inclined with respect to the line. [1], wherein the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator so that the second extension part and the third extension part are located on the other side. It may also be a "laser processing device". According to the laser processing apparatus described in [6], the crack extending from the modified region can be inclined to a desired side.
　本開示の一側面のレーザ加工装置は、［７］「前記ラインとして前記対象物に設定された第１ライン及び第２ラインのそれぞれに沿って前記集光スポットを相対的に移動させる場合において、前記第１ラインに沿って前記集光スポットを相対的に移動させる向きと、前記第２ラインに沿って前記集光スポットを相対的に移動させる向きとが異なるときには、前記制御部は、前記第１ライン及び前記第２ラインのそれぞれに対して前記一方の側に前記第１延在部が位置し且つ前記第１ライン及び前記第２ラインのそれぞれに対して他方の側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンの向きを切り替える、上記［６］に記載のレーザ加工装置」であってもよい。当該［７］に記載のレーザ加工装置によれば、第１ラインに沿って集光スポットを相対的に移動させる向きと、第２ラインに沿って集光スポットを相対的に移動させる向きとが異なる場合にも、第１ライン及び第２ラインのそれぞれに対して一方の側に第１延在部が位置し且つ第１ライン及び第２ラインのそれぞれに対して他方の側に第２延在部及び第３延在部が位置する状態を容易に且つ確実に実現することができる。 The laser processing device according to one aspect of the present disclosure includes [7] “In the case where the focused spot is relatively moved along each of a first line and a second line set on the object as the line, When the direction in which the focused spot is relatively moved along the first line is different from the direction in which the focused spot is relatively moved along the second line, the control unit The first extending portion is located on the one side with respect to each of the first line and the second line, and the second extending portion is located on the other side with respect to each of the first line and the second line. The laser processing apparatus according to item [6] above may change the direction of the modulation pattern including the trefoil aberration pattern so that the trefoil aberration pattern and the third extension portion are located. According to the laser processing apparatus described in [7], the direction in which the focused spot is relatively moved along the first line and the direction in which the focused spot is relatively moved along the second line are different. Even in different cases, the first extension part is located on one side with respect to each of the first line and the second line, and the second extension part is located on the other side with respect to each of the first line and the second line. It is possible to easily and reliably realize the state in which the third extension part and the third extension part are located.
　本開示の一側面のレーザ加工装置は、［８］「前記制御部は、前記第１面と前記第２面との間の角度を第１角度とする場合には、第１トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させ、前記角度を前記第１角度よりも大きい第２角度とする場合には、前記第１トレフォイル収差強度よりも強い第２トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、上記［６］又は［７］に記載のレーザ加工装置」であってもよい。当該［８］に記載のレーザ加工装置によれば、改質領域から延在する亀裂が傾斜する角度を、加工に応じて適切な角度にすることができる。 The laser processing device according to one aspect of the present disclosure includes [8] “When the angle between the first surface and the second surface is the first angle, the control unit controls the first trefoil aberration intensity. When the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator and the angle is a second angle larger than the first angle, a second trefoil aberration intensity stronger than the first trefoil aberration intensity is used. The laser processing apparatus according to [6] or [7] above may display the modulation pattern including the trefoil aberration pattern of aberration intensity on the spatial light modulator. According to the laser processing apparatus described in [8], the angle at which the crack extending from the modified region is inclined can be set to an appropriate angle depending on the processing.
　本開示の一側面のレーザ加工方法は、［９］「対象物を支持する支持部と、レーザ光を出射する光源と、変調パターンを表示することで、前記光源から出射された前記レーザ光を変調する空間光変調器と、前記空間光変調器によって変調された前記レーザ光を前記対象物に集光する集光部と、前記支持部及び前記集光部の少なくとも一方を駆動する駆動部と、を備えるレーザ加工装置において実施されるレーザ加工方法であって、前記レーザ光の集光スポットにおける前記レーザ光のビーム形状が、中心部並びに前記中心部から放射状に延在する第１延在部、第２延在部及び第３延在部を含み且つ前記中心部において最も高い強度を有するビーム形状となるように、トレフォイル収差パターンを含む変調パターンを前記空間光変調器に表示させる工程と、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させた状態で、前記対象物に設定されたラインに沿って前記集光スポットが相対的に移動するように、前記支持部及び前記集光部の少なくとも一方を前記駆動部に駆動させる工程と、を備える、レーザ加工方法」である。 A laser processing method according to one aspect of the present disclosure includes [9] "a supporting part that supports a target object, a light source that emits a laser beam, and a modulation pattern that is displayed, so that the laser beam that is emitted from the light source is a spatial light modulator that modulates the laser beam, a focusing section that focuses the laser beam modulated by the spatial light modulator on the object, and a driving section that drives at least one of the support section and the focusing section. A laser processing method carried out in a laser processing apparatus comprising: a beam shape of the laser light at a focused spot of the laser light includes a center portion and a first extension portion extending radially from the center portion; , displaying a modulation pattern including a trefoil aberration pattern on the spatial light modulator so as to have a beam shape that includes a second extension part and a third extension part and has the highest intensity at the center; The supporting portion and a step of causing the driving section to drive at least one of the light condensing sections.''
　上記［９］に記載のレーザ加工方法では、集光スポットにおけるレーザ光のビーム形状が、中心部並びに中心部から放射状に延在する第１延在部、第２延在部及び第３延在部を含み且つ中心部において最も高い強度を有する状態で、当該集光スポットが、対象物に設定されたラインに沿って相対的に移動させられる。このとき、ラインに対するビーム形状の向き等を調整することで、対象物に形成される改質領域及び亀裂の少なくとも一方の状態を調整することができる。よって、上記［９］に記載のレーザ加工方法によれば、加工に応じて適切な改質領域及び亀裂を対象物に形成することができる。 In the laser processing method described in [9] above, the beam shape of the laser beam at the condensed spot includes a central portion, a first extending portion, a second extending portion, and a third extending portion extending radially from the central portion. The focused spot is relatively moved along a line set on the object, with the focus having the highest intensity at the center. At this time, by adjusting the direction of the beam shape with respect to the line, etc., the state of at least one of the modified region and the cracks formed in the object can be adjusted. Therefore, according to the laser processing method described in [9] above, appropriate modified regions and cracks can be formed in the object depending on the processing.
　本開示によれば、加工に応じて適切な改質領域及び亀裂を対象物に形成することができるレーザ加工装置及びレーザ加工方法を提供することが可能となる。 According to the present disclosure, it is possible to provide a laser processing device and a laser processing method that can form appropriate modified regions and cracks in a target object depending on the processing.
図１は、一実施形態のレーザ加工装置の構成を示す図である。FIG. 1 is a diagram showing the configuration of a laser processing apparatus according to an embodiment. 図２は、図１に示される照射部の構成を示す図である。FIG. 2 is a diagram showing the configuration of the irradiation section shown in FIG. 1. 図３は、図２に示される４ｆレンズユニットを示す図である。FIG. 3 is a diagram showing the 4f lens unit shown in FIG. 2. 図４は、図２に示される空間光変調器を示す図である。FIG. 4 is a diagram showing the spatial light modulator shown in FIG. 2. 図５は、トレフォイル収差パターンの一例を示す図である。FIG. 5 is a diagram showing an example of a trefoil aberration pattern. 図６は、レーザ光の集光状態の一例、及び集光スポットにおけるレーザ光のビーム形状の一例を示す図である。FIG. 6 is a diagram showing an example of a focused state of laser light and an example of a beam shape of the laser light at the focused spot. 図７は、トレフォイル収差強度ごとのレーザ光のビーム形状の一例を示す図である。FIG. 7 is a diagram showing an example of a beam shape of a laser beam for each trefoil aberration intensity. 図８は、トレフォイル収差パターンによって変調されたレーザ光のビーム形状の一例を示す図である。FIG. 8 is a diagram showing an example of a beam shape of laser light modulated by a trefoil aberration pattern. 図９は、トレフォイル収差パターン及び非点収差パターンによって変調されたレーザ光のビーム形状の一例を示す図である。FIG. 9 is a diagram showing an example of a beam shape of a laser beam modulated by a trefoil aberration pattern and an astigmatism pattern. 図１０は、トレフォイル収差パターン、非点収差パターン及び球面収差パターンによって変調されたレーザ光のビーム形状の一例を示す図である。FIG. 10 is a diagram showing an example of a beam shape of laser light modulated by a trefoil aberration pattern, an astigmatism pattern, and a spherical aberration pattern. 図１１は、トレフォイル収差パターンによって変調されたレーザ光のビーム形状の一例を示す図である。FIG. 11 is a diagram showing an example of a beam shape of laser light modulated by a trefoil aberration pattern. 図１２は、レーザ光の集光状態の一例、及びレーザ光の抜け光によるダメージの一例を示す図である。FIG. 12 is a diagram illustrating an example of a focused state of laser light and an example of damage caused by light leakage of laser light. 図１３は、レーザ加工条件ごとの対象物の切断面の第１例を示す図である。FIG. 13 is a diagram showing a first example of a cut surface of a target object for each laser processing condition. 図１４は、レーザ加工条件ごとの対象物の切断面の第１例を示す図である。FIG. 14 is a diagram showing a first example of a cut surface of a target object for each laser processing condition. 図１５は、トレフォイル収差強度と改質領域及び亀裂のそれぞれの幅との関係を示す図である。FIG. 15 is a diagram showing the relationship between the trefoil aberration intensity and the respective widths of the modified region and crack. 図１６は、レーザ加工条件ごとの対象物の切断面の第２例を示す図である。FIG. 16 is a diagram showing a second example of the cut surface of the object for each laser processing condition. 図１７は、レーザ加工条件ごとの対象物の切断面の第２例を示す図である。FIG. 17 is a diagram showing a second example of the cut surface of the object for each laser processing condition. 図１８は、トレフォイル収差強度と亀裂が傾斜する角度との関係を示す図である。FIG. 18 is a diagram showing the relationship between the trefoil aberration intensity and the angle at which the crack is inclined. 図１９は、トレフォイル収差強度と亀裂が傾斜する角度との関係を示す図である。FIG. 19 is a diagram showing the relationship between the trefoil aberration intensity and the angle at which the crack is inclined. 図２０は、レーザ加工方法の第１例が適用される対象物を示す図である。FIG. 20 is a diagram showing an object to which the first example of the laser processing method is applied. 図２１は、レーザ加工方法の第１例の一工程を示す図である。FIG. 21 is a diagram showing one step of the first example of the laser processing method. 図２２は、抜け光ダメージ抑制加工による対象物の切断面の例を示す図である。FIG. 22 is a diagram illustrating an example of a cut surface of an object subjected to light damage suppression processing. 図２３は、レーザ加工方法の第２例が適用される対象物を示す図である。FIG. 23 is a diagram showing an object to which the second example of the laser processing method is applied. 図２４は、レーザ加工方法の第２例の一工程を示す図である。FIG. 24 is a diagram showing one step of the second example of the laser processing method.
　以下、本開示の実施形態について、図面を参照して詳細に説明する。なお、各図において同一又は相当部分には同一符号を付し、重複する説明を省略する。
［レーザ加工装置の構成］ Embodiments of the present disclosure will be described in detail below with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations will be omitted.
[Laser processing equipment configuration]
　図１に示されるように、レーザ加工装置１は、支持部２と、照射部３と、駆動部４，５と、制御部６と、を備えている。レーザ加工装置１は、対象物１１にレーザ光Ｌを照射することで、対象物１１に改質領域１２を形成する。 As shown in FIG. 1, the laser processing device 1 includes a support section 2, an irradiation section 3, drive sections 4 and 5, and a control section 6. The laser processing apparatus 1 forms a modified region 12 on the object 11 by irradiating the object 11 with a laser beam L.
　支持部２は、例えば対象物１１に貼り付けられたフィルムを保持することで、対象物１１を支持する。本実施形態では、支持部２は、Ｘ方向及びＹ方向のそれぞれの方向に移動可能であり、Ｚ方向に平行な軸線を回転軸として回転可能である。一例として、Ｘ方向及びＹ方向は、互いに垂直な第１水平方向及び第２水平方向であり、Ｚ方向は、鉛直方向である。 The support section 2 supports the object 11 by holding a film attached to the object 11, for example. In this embodiment, the support part 2 is movable in each of the X direction and the Y direction, and is rotatable about an axis parallel to the Z direction as a rotation axis. As an example, the X direction and the Y direction are a first horizontal direction and a second horizontal direction that are perpendicular to each other, and the Z direction is a vertical direction.
　照射部３は、対象物１１に対して透過性を有するレーザ光Ｌを集光して対象物１１に照射する。本実施形態では、照射部３は、Ｚ方向に移動可能である。支持部２に支持された対象物１１の内部にレーザ光Ｌが集光されると、レーザ光Ｌの集光スポットＣに対応する部分においてレーザ光Ｌが特に吸収され、対象物１１の内部に改質領域１２が形成される。なお、集光スポットＣは、集光領域又は集光点とも称される。 The irradiation unit 3 focuses a laser beam L that is transparent to the object 11 and irradiates the object 11 with the laser beam L. In this embodiment, the irradiation unit 3 is movable in the Z direction. When the laser beam L is focused inside the object 11 supported by the support part 2, the laser beam L is particularly absorbed in the part corresponding to the focused spot C of the laser beam L, and the laser beam L is absorbed inside the object 11. A modified region 12 is formed. Note that the focused spot C is also referred to as a focused area or a focused point.
　改質領域１２は、密度、屈折率、機械的強度、その他の物理的特性が周囲の非改質領域とは異なる領域である。改質領域１２としては、例えば、溶融処理領域、クラック領域、絶縁破壊領域、屈折率変化領域等がある。改質領域１２からは、レーザ光Ｌの入射側及びその反対側に亀裂が形成される。そのような改質領域１２及び亀裂は、対象物１１の切断に利用される。 The modified region 12 is a region whose density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding unmodified region. Examples of the modified region 12 include a melt-treated region, a crack region, a dielectric breakdown region, and a refractive index change region. From the modified region 12, cracks are formed on the incident side of the laser beam L and on the opposite side. Such modified regions 12 and cracks are used to cut the object 11.
　一例として、対象物１１に設定されたＸ方向に平行なラインＡに沿って集光スポットＣが相対的に移動させられると、ラインＡに沿って複数の改質スポット１２ｓが１列に並ぶように形成される。一つの改質スポット１２ｓは、１パルスのレーザ光Ｌの照射によって形成される。１列の改質領域１２は、１列に並んだ複数の改質スポット１２ｓの集合である。隣り合う改質スポット１２ｓは、対象物１１に対する集光スポットＣの相対的な移動速度及びレーザ光Ｌの繰り返し周波数によって、互いに繋がる場合もあるし、互いに離れる場合もある。 As an example, when the focused spot C is relatively moved along a line A parallel to the X direction set on the object 11, a plurality of modified spots 12s are lined up in a line along the line A. is formed. One modification spot 12s is formed by irradiation with one pulse of laser light L. One row of modified regions 12 is a collection of a plurality of modified spots 12s arranged in one row. Adjacent modification spots 12s may be connected to each other or separated from each other depending on the relative moving speed of the focused spot C with respect to the object 11 and the repetition frequency of the laser beam L.
　駆動部４は、支持部２を支持しており、支持部２を駆動する。本実施形態では、駆動部４は、Ｘ方向及びＹ方向のそれぞれの方向に支持部２を移動させ、Ｚ方向に平行な軸線を回転軸として支持部２を回転させる。駆動部５は、照射部３を支持しており、照射部３を駆動する。本実施形態では、駆動部５は、Ｚ方向に照射部３を移動させる。一例として、レーザ加工装置１では、ラインＡがＸ方向に平行となるように駆動部４が支持部２を回転させ、集光スポットＣがラインＡ上に位置するように駆動部４が支持部２をＹ方向に移動させ、集光スポットＣが対象物１１の内部に位置するように駆動部５がＺ方向に照射部３を移動させ、更に、ラインＡに沿って集光スポットＣが相対的に移動するように駆動部４が支持部２を移動させる。 The drive section 4 supports the support section 2 and drives the support section 2. In this embodiment, the drive unit 4 moves the support unit 2 in each of the X direction and the Y direction, and rotates the support unit 2 using an axis parallel to the Z direction as the rotation axis. The drive section 5 supports the irradiation section 3 and drives the irradiation section 3. In this embodiment, the drive section 5 moves the irradiation section 3 in the Z direction. As an example, in the laser processing apparatus 1, the drive unit 4 rotates the support unit 2 so that the line A is parallel to the X direction, and the drive unit 4 rotates the support unit so that the focused spot C is located on the line A. 2 in the Y direction, the drive unit 5 moves the irradiation unit 3 in the Z direction so that the focused spot C is located inside the object 11, and further, the focused spot C is moved relative to the target object 11 along the line A. The drive section 4 moves the support section 2 so as to move the support section 2 as desired.
　制御部６は、支持部２、照射部３及び駆動部４，５を制御する。制御部６は、処理部、記憶部及び入力受付部を有している（図示省略）。処理部は、プロセッサ、メモリ、ストレージ及び通信デバイス等を含むコンピュータ装置として構成されている。処理部では、プロセッサが、メモリ等に読み込まれたソフトウェア（プログラム）を実行し、メモリ及びストレージにおけるデータの読み出し及び書き込み、並びに、通信デバイスによる通信が制御される。記憶部は、例えばハードディスク等であり、各種データを記憶する。入力受付部は、各種情報を表示すると共に、ユーザから各種情報の入力を受け付けるインターフェース部である。入力受付部は、例えば、ＧＵＩ（Graphical　User　Interface）を構成している。 The control unit 6 controls the support unit 2, the irradiation unit 3, and the drive units 4 and 5. The control unit 6 has a processing unit, a memory unit, and an input reception unit (not shown). The processing unit is configured as a computer device including a processor, memory, storage, and a communication device. In the processing unit, the processor executes software (programs) loaded into the memory, etc., and controls the reading and writing of data in the memory and storage, as well as communication by the communication device. The memory unit is, for example, a hard disk, and stores various types of data. The input reception unit is an interface unit that displays various types of information and receives input of various types of information from the user. The input reception unit constitutes, for example, a GUI (Graphical User Interface).
　図２に示されるように、照射部３は、光源３１と、空間光変調器７と、集光部３３と、４ｆレンズユニット３４と、を有している。光源３１は、例えばパルス発振方式によって、レーザ光Ｌを出射する。空間光変調器７は、変調パターンを表示することで、光源３１から出射されたレーザ光Ｌを変調する。集光部３３は、少なくとも一つのレンズによって構成されており、空間光変調器７によって変調されたレーザ光Ｌを対象物１１に集光する。４ｆレンズユニット３４は、空間光変調器７の変調面でのレーザ光Ｌの像を集光部３３の入射瞳面に転像する。なお、光源３１が照射部３の外部に設けられており、光源３１から出射されたレーザ光Ｌが照射部３に導光されてもよい。また、照射部３は、他の光学系を備えていてもよい。一例として、照射部３は、光源３１と空間光変調器７との間の光路上に配置された光学系（例えば、アッテネータ、ビームエキスパンダ等）を備えていてもよい。 As shown in FIG. 2, the irradiation section 3 includes a light source 31, a spatial light modulator 7, a condensing section 33, and a 4f lens unit 34. The light source 31 emits laser light L using, for example, a pulse oscillation method. The spatial light modulator 7 modulates the laser beam L emitted from the light source 31 by displaying a modulation pattern. The condensing unit 33 includes at least one lens, and condenses the laser beam L modulated by the spatial light modulator 7 onto the object 11 . The 4f lens unit 34 transfers the image of the laser beam L on the modulation surface of the spatial light modulator 7 to the entrance pupil surface of the condenser 33 . Note that the light source 31 may be provided outside the irradiation section 3 and the laser light L emitted from the light source 31 may be guided to the irradiation section 3. Further, the irradiation unit 3 may include other optical systems. As an example, the irradiation unit 3 may include an optical system (for example, an attenuator, a beam expander, etc.) arranged on the optical path between the light source 31 and the spatial light modulator 7.
　図３に示されるように、４ｆレンズユニット３４は、一対のレンズ３４Ａ，３４Ｂを有している。一対のレンズ３４Ａ，３４Ｂは、空間光変調器７から集光部３３に進行するレーザ光Ｌの光路上に配置されている。一対のレンズ３４Ａ，３４Ｂは、空間光変調器７の変調面７ａと集光部３３の入射瞳面３３ａとが結像関係にある両側テレセントリック光学系を構成している。これにより、空間光変調器７の変調面７ａでのレーザ光Ｌの像（空間光変調器７において変調されたレーザ光Ｌの像）が集光部３３の入射瞳面３３ａに転像（結像）される。なお、図３において、ｆ１，ｆ２はそれぞれレンズ３４Ａ，３４Ｂの焦点距離を示し、Ｆｓはフーリエ面を示す。 As shown in FIG. 3, the 4f lens unit 34 has a pair of lenses 34A and 34B. The pair of lenses 34A and 34B are arranged on the optical path of the laser beam L traveling from the spatial light modulator 7 to the condensing section 33. The pair of lenses 34A and 34B constitute a double-sided telecentric optical system in which the modulation surface 7a of the spatial light modulator 7 and the entrance pupil surface 33a of the condenser 33 are in an imaging relationship. As a result, the image of the laser beam L on the modulation surface 7a of the spatial light modulator 7 (the image of the laser beam L modulated in the spatial light modulator 7) is transferred (formed) onto the entrance pupil plane 33a of the condenser 33. image) to be done. In addition, in FIG. 3, f1 and f2 indicate the focal lengths of the lenses 34A and 34B, respectively, and Fs indicates the Fourier plane.
　図４に示されるように、空間光変調器７は、反射型液晶（ＬＣＯＳ：Liquid　Crystal　on　Silicon）の空間光変調器（ＳＬＭ：Spatial　Light　Modulator）である。空間光変調器７は、半導体基板７１上に、駆動回路層７２、画素電極層７３、反射膜７４、配向膜７５、液晶層７６、配向膜７７、透明導電膜７８及び透明基板７９がこの順序で積層されることで、構成されている。 As shown in FIG. 4, the spatial light modulator 7 is a reflective liquid crystal (LCOS) spatial light modulator (SLM). In the spatial light modulator 7, a drive 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 are arranged on a semiconductor substrate 71 in this order. It is constructed by laminating layers.
　半導体基板７１は、例えば、シリコン基板である。駆動回路層７２は、半導体基板７１上において、アクティブ・マトリクス回路を構成している。画素電極層７３は、半導体基板７１の表面に沿ってマトリックス状に配列された複数の画素電極７３ａを含んでいる。各画素電極７３ａは、例えば、アルミニウム等の金属材料によって形成されている。各画素電極７３ａには、駆動回路層７２によって電圧が印加される。 The semiconductor substrate 71 is, for example, a silicon substrate. The drive circuit layer 72 constitutes an active matrix circuit on the semiconductor substrate 71. The pixel electrode layer 73 includes a plurality of pixel electrodes 73a arranged in a matrix along the surface of the semiconductor substrate 71. Each pixel electrode 73a is made of, for example, a metal material such as aluminum. A voltage is applied to each pixel electrode 73a by the drive circuit layer 72.
　反射膜７４は、例えば、誘電体多層膜である。配向膜７５は、液晶層７６における反射膜７４側の表面に設けられており、配向膜７７は、液晶層７６における反射膜７４とは反対側の表面に設けられている。各配向膜７５，７７は、例えば、ポリイミド等の高分子材料によって形成されており、各配向膜７５，７７における液晶層７６との接触面には、例えば、ラビング処理が施されている。配向膜７５，７７は、液晶層７６に含まれる液晶分子７６ａを一定方向に配列させる。 The reflective film 74 is, for example, a dielectric multilayer film. The alignment film 75 is provided on the surface of the liquid crystal layer 76 on the reflective film 74 side, and the alignment film 77 is provided on the surface of the liquid crystal layer 76 on the opposite side to the reflective film 74. Each of the alignment films 75 and 77 is made of, for example, a polymeric material such as polyimide, and the contact surface of each of the alignment films 75 and 77 with the liquid crystal layer 76 is subjected to, for example, a rubbing treatment. The alignment films 75 and 77 align liquid crystal molecules 76a included in the liquid crystal layer 76 in a certain direction.
　透明導電膜７８は、透明基板７９における配向膜７７側の表面に設けられており、液晶層７６等を挟んで画素電極層７３と向かい合っている。透明基板７９は、例えば、ガラス基板である。透明導電膜７８は、例えば、ＩＴＯ等の光透過性且つ導電性材料によって形成されている。透明基板７９及び透明導電膜７８は、レーザ光Ｌを透過させる。 The transparent conductive film 78 is provided on the surface of the transparent substrate 79 on the alignment film 77 side, and faces the pixel electrode layer 73 with the liquid crystal layer 76 and the like interposed therebetween. The transparent substrate 79 is, for example, a glass substrate. The transparent conductive film 78 is made of a light-transmissive and conductive material such as ITO, for example. The transparent substrate 79 and the transparent conductive film 78 transmit the laser beam L.
　以上のように構成された空間光変調器７では、変調パターンを示す信号が制御部６から駆動回路層７２に入力されると、当該信号に応じた電圧が各画素電極７３ａに印加され、各画素電極７３ａと透明導電膜７８との間に電界が形成される。当該電界が形成されると、液晶層７６において、各画素電極７３ａに対応する領域ごとに液晶分子７６ａの配列方向が変化し、各画素電極７３ａに対応する領域ごとに屈折率が変化する。この状態が、空間光変調器７が変調パターンを表示した状態である。 In the spatial light modulator 7 configured as described above, when a signal indicating a modulation pattern is input from the control unit 6 to the drive circuit layer 72, a voltage corresponding to the signal is applied to each pixel electrode 73a, and each An electric field is formed between the pixel electrode 73a and the transparent conductive film 78. When the electric field is formed, in the liquid crystal layer 76, the alignment direction of the liquid crystal molecules 76a changes for each region corresponding to each pixel electrode 73a, and the refractive index changes for each region corresponding to each pixel electrode 73a. This state is the state in which the spatial light modulator 7 displays a modulation pattern.
　空間光変調器７が変調パターンを表示した状態で、レーザ光Ｌが、外部から透明基板７９及び透明導電膜７８を介して液晶層７６に入射し、反射膜７４で反射されて、液晶層７６から透明導電膜７８及び透明基板７９を介して外部に出射させられると、液晶層７６に表示された変調パターンに応じて、レーザ光Ｌの強度、振幅、位相、偏光等が変調される。なお、図３に示される変調面７ａは、液晶層７６に対応する。
［トレフォイル収差パターンを用いたレーザ加工方法］ With the spatial light modulator 7 displaying a modulation pattern, the laser beam L enters the liquid crystal layer 76 from the outside via the transparent substrate 79 and the transparent conductive film 78, is reflected by the reflective film 74, and the laser beam L enters the liquid crystal layer 76 from the outside through the transparent substrate 79 and the transparent conductive film 78. When the laser beam L is emitted to the outside through the transparent conductive film 78 and the transparent substrate 79, the intensity, amplitude, phase, polarization, etc. of the laser beam L are modulated according to the modulation pattern displayed on the liquid crystal layer 76. Note that the modulation surface 7a shown in FIG. 3 corresponds to the liquid crystal layer 76.
[Laser processing method using Trefoil aberration pattern]
　レーザ加工装置１において、制御部６は、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させることができる。図５は、トレフォイル収差パターンの一例を示す図である。トレフォイル収差は、ゼルニケの三次収差の一つである。なお、球面収差及び非点収差はゼルニケの二次収差に含まれ、コマ収差及びトレフォイル収差はゼルニケの三次収差に含まれる。 In the laser processing apparatus 1, the control unit 6 can cause the spatial light modulator 7 to display a modulation pattern including a trefoil aberration pattern. FIG. 5 is a diagram showing an example of a trefoil aberration pattern. Trefoil aberration is one of Zernike's third-order aberrations. Note that spherical aberration and astigmatism are included in Zernike's second-order aberration, and coma aberration and trefoil aberration are included in Zernike's third-order aberration.
　トレフォイル収差パターンを表示した空間光変調器７によって変調されたレーザ光Ｌが集光部３３によって集光されると、図６の（ａ）に示されるように、レーザ光Ｌは、集光スポットＣにおいて最も絞られる。このとき、集光スポットＣにおけるレーザ光Ｌのビーム形状９（すなわち、「レーザ光Ｌの光軸（図６の（ａ）に示される一点鎖線）に垂直であり且つ集光スポットＣを含む面」内でのレーザ光Ｌの強度分布）は、図６の（ｂ）に示されるように、中心部９０並びに中心部９０から放射状に延在する第１延在部９１、第２延在部９２及び第３延在部９３を含み且つ中心部９０において最も高い強度を有するビーム形状となる。一例として、第１延在部９１、第２延在部９２及び第３延在部９３のそれぞれの幅は、中心部９０から離れるほど小さくなっており、第１延在部９１、第２延在部９２及び第３延在部９３のそれぞれの強度は、中心部９０から離れるほど低くなっている。一例として、レーザ光Ｌのビーム形状９は、三角形の各辺が内側に湾曲したような形状である。 When the laser beam L modulated by the spatial light modulator 7 displaying the trefoil aberration pattern is focused by the condenser 33, the laser beam L becomes a condensed spot, as shown in FIG. 6(a). It is most narrowed down in C. At this time, the beam shape 9 of the laser beam L at the condensed spot C (i.e., a surface that is perpendicular to the optical axis of the laser beam L (dotted chain line shown in FIG. 6(a)) and includes the condensed spot C. As shown in FIG. 92 and the third extending portion 93, and has the highest strength at the center portion 90. As an example, the width of each of the first extending portion 91, the second extending portion 92, and the third extending portion 93 becomes smaller as the distance from the center portion 90 increases. The strength of each of the existing portion 92 and the third extending portion 93 decreases as the distance from the center portion 90 increases. As an example, the beam shape 9 of the laser beam L is like a triangle with each side curved inward.
　なお、トレフォイル収差パターンを含む変調パターンには、トレフォイル収差パターンのみを含む変調パターンは勿論、トレフォイル収差パターン及びそれ以外のパターンを含む変調パターンも含まれる。変調パターンがトレフォイル収差パターン以外のパターンを含んでいる場合にも、トレフォイル収差パターンを含む変調パターンを表示した空間光変調器７によって変調されたレーザ光Ｌが集光部３３によって集光されると、集光スポットＣにおけるレーザ光Ｌのビーム形状９が、中心部９０並びに中心部９０から放射状に延在する第１延在部９１、第２延在部９２及び第３延在部９３を含み且つ中心部９０において最も高い強度を有するビーム形状となる。一例として、トレフォイル収差パターン及び非点収差パターンを含む変調パターンを表示した空間光変調器７によって変調されたレーザ光Ｌが集光部３３によって集光されると、複数の集光スポットＣが現れる場合があるが、そのような場合にも、各集光スポットＣにおけるレーザ光Ｌのビーム形状９（この場合、「集光スポットＣに集光されるレーザ光Ｌの光軸に垂直であり且つ集光スポットＣを含む面」内でのレーザ光Ｌの強度分布）は、中心部９０並びに中心部９０から放射状に延在する第１延在部９１、第２延在部９２及び第３延在部９３を含み且つ中心部９０において最も高い強度を有するビーム形状となる。 Note that the modulation pattern including a trefoil aberration pattern includes not only a modulation pattern including only a trefoil aberration pattern, but also a modulation pattern including a trefoil aberration pattern and other patterns. Even when the modulation pattern includes a pattern other than the trefoil aberration pattern, when the laser beam L modulated by the spatial light modulator 7 displaying the modulation pattern including the trefoil aberration pattern is condensed by the condenser 33. , the beam shape 9 of the laser beam L at the focused spot C includes a center portion 90 and a first extending portion 91, a second extending portion 92, and a third extending portion 93 extending radially from the center portion 90. Moreover, the beam shape has the highest intensity at the center portion 90. As an example, when the laser beam L modulated by the spatial light modulator 7 that displays a modulation pattern including a trefoil aberration pattern and an astigmatism pattern is focused by the focusing unit 33, a plurality of focused spots C appear. However, even in such a case, the beam shape 9 of the laser light L at each focused spot C (in this case, "perpendicular to the optical axis of the laser light L focused on the focused spot C and The intensity distribution of the laser beam L within the plane including the focused spot C is determined by the center portion 90 and the first extending portions 91, second extending portions 92, and third extending portions extending radially from the center portion 90. The beam shape includes the existing portion 93 and has the highest strength at the center portion 90.
　図７は、トレフォイル収差強度ごとのレーザ光Ｌのビーム形状の一例を示す図である。トレフォイル収差強度の絶対値はトレフォイル収差の強さを示し、トレフォイル収差強度の絶対値が大きくなるほどトレフォイル収差が強くなる（したがって、「トレフォイル収差強度が強い」とは、トレフォイル収差強度の絶対値が大きいこと意味する）。トレフォイル収差強度の正負の符号はトレフォイル収差の向きを示し、正の符号を有するトレフォイル収差と負の符号を有するトレフォイル収差とではトレフォイル収差の向きが１８０度異なる。図７には、レーザ光Ｌのビーム形状として、カメラによって撮像されたカメラ像が示されている。 FIG. 7 is a diagram showing an example of the beam shape of the laser light L for each trefoil aberration intensity. The absolute value of the trefoil aberration strength indicates the strength of the trefoil aberration, and the larger the absolute value of the trefoil aberration strength, the stronger the trefoil aberration (therefore, "the trefoil aberration strength is strong" means that the absolute value of the trefoil aberration strength is large) (meaning). The positive or negative sign of the trefoil aberration intensity indicates the direction of the trefoil aberration, and the direction of the trefoil aberration differs by 180 degrees between the trefoil aberration having a positive sign and the trefoil aberration having a negative sign. FIG. 7 shows a camera image taken by a camera as the beam shape of the laser light L.
　図７に示されるように、いずれのトレフォイル収差強度を有するトレフォイル収差パターンによってレーザ光Ｌが変調された場合にも、集光スポットＣにおけるレーザ光Ｌのビーム形状９は、中心部９０並びに第１延在部９１、第２延在部９２及び第３延在部９３を含み且つ中心部９０において最も高い強度を有するビーム形状となる（図６の（ｂ）参照）。このとき、－２０μｍの位置におけるレーザ光Ｌのビーム形状、及び＋２０μｍの位置におけるレーザ光Ｌのビーム形状も、集光スポットＣにおけるレーザ光Ｌのビーム形状９と同様の形状及び向きを有するビーム形状となる。集光スポットＣにおけるレーザ光Ｌのビーム形状９は、カメラ像を一見すると、－２０μｍの位置におけるレーザ光Ｌのビーム形状、及び＋２０μｍの位置におけるレーザ光Ｌのビーム形状とは逆側に向いているように見える場合があるが、そのような場合にも、強度が高い部分だけでなく強度が低い部分まで含めると、それらのビーム形状と同じ側に向いていることが分かる。なお、「－２０μｍの位置」は、集光スポットＣから集光部３３側に２０μｍ離れた位置であり、「＋２０μｍの位置」は、集光スポットＣから集光部３３とは反対側に２０μｍ離れた位置である。 As shown in FIG. 7, even when the laser beam L is modulated by the trefoil aberration pattern having any trefoil aberration intensity, the beam shape 9 of the laser beam L at the focused spot C is The beam shape includes the extending portion 91, the second extending portion 92, and the third extending portion 93 and has the highest strength at the center portion 90 (see (b) of FIG. 6). At this time, the beam shape of the laser light L at the -20 μm position and the beam shape of the laser light L at the +20 μm position also have the same shape and direction as the beam shape 9 of the laser light L at the focused spot C. becomes. When looking at the camera image at a glance, the beam shape 9 of the laser light L at the focused spot C is oriented to the opposite side from the beam shape of the laser light L at the -20 μm position and the beam shape of the laser light L at the +20 μm position. However, even in such cases, if you include not only the high-intensity parts but also the low-intensity parts, you can see that they are facing the same side as the beam shape. Note that the "-20 μm position" is a position 20 μm away from the condensing spot C toward the condensing unit 33, and the "+20 μm position" is 20 μm away from the condensing spot C on the side opposite to the condensing unit 33. It is a remote location.
　図８は、トレフォイル収差パターンによって変調されたレーザ光Ｌのビーム形状の一例を示す図である。図９は、トレフォイル収差パターン及び非点収差パターン（すなわち、それらが重畳された変調パターン）によって変調されたレーザ光Ｌのビーム形状の一例を示す図である。図１０は、トレフォイル収差パターン、非点収差パターン及び球面収差パターン（すなわち、それらが重畳された変調パターン）によって変調されたレーザ光Ｌのビーム形状の一例を示す図である。図８、図９及び図１０には、レーザ光Ｌのビーム形状として、シミュレーションによって取得されたシミュレーション像、及びカメラによって撮像されたカメラ像が示されている。なお、図８、図９及び図１０のいずれの場合も、トレフォイル収差パターンのトレフォイル収差強度は－０．６である。 FIG. 8 is a diagram showing an example of the beam shape of the laser light L modulated by the trefoil aberration pattern. FIG. 9 is a diagram showing an example of a beam shape of laser light L modulated by a trefoil aberration pattern and an astigmatism pattern (that is, a modulation pattern in which they are superimposed). FIG. 10 is a diagram showing an example of a beam shape of laser light L modulated by a trefoil aberration pattern, an astigmatism pattern, and a spherical aberration pattern (that is, a modulation pattern in which they are superimposed). 8, 9, and 10 show a simulation image obtained by simulation and a camera image captured by a camera as the beam shape of the laser light L. In addition, in any case of FIG. 8, FIG. 9, and FIG. 10, the trefoil aberration intensity of the trefoil aberration pattern is -0.6.
　図８、図９及び図１０に示されるように、トレフォイル収差パターンを含む変調パターンによってレーザ光Ｌが変調されると、集光スポットＣにおけるレーザ光Ｌのビーム形状９は、中心部９０並びに第１延在部９１、第２延在部９２及び第３延在部９３を含み且つ中心部９０において最も高い強度を有するビーム形状となる（図６の（ｂ）参照）。このとき、－２０μｍの位置におけるレーザ光Ｌのビーム形状、及び＋２０μｍの位置におけるレーザ光Ｌのビーム形状も、集光スポットＣにおけるレーザ光Ｌのビーム形状９と同様の形状及び向きを有するビーム形状となる。集光スポットＣにおけるレーザ光Ｌのビーム形状９は、カメラ像を一見すると、－２０μｍの位置におけるレーザ光Ｌのビーム形状、及び＋２０μｍの位置におけるレーザ光Ｌのビーム形状とは逆側に向いているように見える場合があるが、そのような場合にも、強度が高い部分だけでなく強度が低い部分まで含めると、それらのビーム形状と同じ側に向いていることが分かる。 As shown in FIGS. 8, 9 and 10, when the laser beam L is modulated by a modulation pattern including a trefoil aberration pattern, the beam shape 9 of the laser beam L at the focused spot C is The beam shape includes the first extending portion 91, the second extending portion 92, and the third extending portion 93 and has the highest strength at the center portion 90 (see (b) of FIG. 6). At this time, the beam shape of the laser light L at the -20 μm position and the beam shape of the laser light L at the +20 μm position also have the same shape and direction as the beam shape 9 of the laser light L at the focused spot C. becomes. When looking at the camera image at a glance, the beam shape 9 of the laser light L at the focused spot C is oriented to the opposite side from the beam shape of the laser light L at the -20 μm position and the beam shape of the laser light L at the +20 μm position. However, even in such cases, if you include not only the high-intensity parts but also the low-intensity parts, you can see that they are facing the same side as the beam shape.
　図１１は、トレフォイル収差パターンによって変調されたレーザ光Ｌのビーム形状の一例を示す図である。この場合、トレフォイル収差パターンのトレフォイル収差強度は－０．５である。図１１に示されるように、－１００μｍの位置におけるレーザ光Ｌのビーム形状、及び＋１００μｍの位置におけるレーザ光Ｌのビーム形状は、集光スポットＣにおけるレーザ光Ｌのビーム形状９とは逆側に向いたビーム形状となる。なお、「－１００μｍの位置」は、集光スポットＣから集光部３３側に１００μｍ離れた位置であり、「＋１００μｍの位置」は、集光スポットＣから集光部３３とは反対側に１００μｍ離れた位置である。 FIG. 11 is a diagram showing an example of the beam shape of the laser light L modulated by the trefoil aberration pattern. In this case, the trefoil aberration intensity of the trefoil aberration pattern is -0.5. As shown in FIG. 11, the beam shape of the laser light L at the -100 μm position and the beam shape of the laser light L at the +100 μm position are on the opposite side to the beam shape 9 of the laser light L at the focused spot C. The beam shape is oriented. Note that the "-100 μm position" is a position 100 μm away from the condensing spot C toward the condensing part 33, and the "+100 μm position" is 100 μm away from the condensing spot C on the side opposite to the condensing part 33. It is a remote location.
　これに対し、上述したように、－２０μｍの位置におけるレーザ光Ｌのビーム形状、及び＋２０μｍの位置におけるレーザ光Ｌのビーム形状は、集光スポットＣにおけるレーザ光Ｌのビーム形状９と同様の形状及び向きを有するビーム形状となる（図７、図８、図９及び図１０参照）。特に、－２０μｍの位置におけるレーザ光Ｌのビーム形状は、＋２０μｍの位置におけるレーザ光Ｌのビーム形状に比べ、集光スポットＣにおけるレーザ光Ｌのビーム形状９を顕著に示している。したがって、トレフォイル収差パターンを含む変調パターンによって変調されたレーザ光Ｌが集光されている場合に、集光スポットＣにおけるレーザ光Ｌのビーム形状９を推定するためには、－２０μｍの位置におけるレーザ光Ｌのビーム形状をカメラによって撮像し、そのカメラ像を観察すればよい。 On the other hand, as described above, the beam shape of the laser light L at the -20 μm position and the beam shape of the laser light L at the +20 μm position are similar to the beam shape 9 of the laser light L at the focused spot C. and a beam shape having a direction (see FIGS. 7, 8, 9, and 10). In particular, the beam shape of the laser light L at the −20 μm position clearly shows the beam shape 9 of the laser light L at the focused spot C compared to the beam shape of the laser light L at the +20 μm position. Therefore, when the laser beam L modulated by a modulation pattern including a trefoil aberration pattern is focused, in order to estimate the beam shape 9 of the laser beam L at the focused spot C, it is necessary to What is necessary is to image the beam shape of the light L with a camera and observe the camera image.
　また、図１２の（ａ）に示されるように、シリコンウェハである対象物１１の第２表面１１ｂに金属膜８を形成し、対象物１１の第１表面１１ａをレーザ光Ｌの入射面として且つ第２表面１１ｂから２０～３０μｍの位置であって対象物１１の内部の位置に集光スポットＣを合わせて、対象物１１にレーザ光Ｌを照射すると、トレフォイル収差パターンを含む変調パターンによって変調されたレーザ光Ｌが集光されている場合には、図１２の（ｂ）に示されるように、集光スポットＣにおけるレーザ光Ｌのビーム形状９と同様の形状及び向きを有するダメージが金属膜８に形成される。したがって、トレフォイル収差パターンを含む変調パターンによって変調されたレーザ光Ｌが集光されている場合に、集光スポットＣにおけるレーザ光Ｌのビーム形状９を推定するためには、上述のように金属膜８にダメージを形成し、そのダメージを観察すればよい。 Further, as shown in FIG. 12(a), a metal film 8 is formed on the second surface 11b of the object 11, which is a silicon wafer, and the first surface 11a of the object 11 is used as the incident surface of the laser beam L. When the laser beam L is irradiated onto the object 11 by aligning the focused spot C with a position 20 to 30 μm from the second surface 11b and inside the object 11, the laser beam L is modulated by a modulation pattern including a trefoil aberration pattern. When the laser beam L is focused, damage having the same shape and direction as the beam shape 9 of the laser beam L at the focused spot C occurs on the metal, as shown in FIG. The film 8 is formed. Therefore, in order to estimate the beam shape 9 of the laser light L at the focused spot C when the laser light L modulated by the modulation pattern including the trefoil aberration pattern is focused, it is necessary to 8 and observe the damage.
　以上を踏まえ、トレフォイル収差パターンを用いたレーザ加工方法によって形成される改質領域及び亀裂（改質領域の形成時に改質領域から延在する亀裂）の第１例について説明する。図１３及び図１４は、レーザ加工条件ごとの対象物１１の切断面の第１例を示す図である。図１３及び図１４には、「シリコンウェハである対象物１１の内部に、シリコンウェハの厚さ方向に並ぶ二列の改質領域がラインＡに沿って形成され、その後に、対象物１１がエキスパンドによってラインＡに沿って切断された場合」における対象物１１の切断面が示されている。 Based on the above, a first example of a modified region and a crack (a crack extending from the modified region when the modified region is formed) formed by a laser processing method using a trefoil aberration pattern will be described. 13 and 14 are diagrams showing first examples of cut surfaces of the object 11 for each laser processing condition. 13 and 14, "Two rows of modified regions aligned in the thickness direction of the silicon wafer are formed inside the object 11, which is a silicon wafer, along line A, and then the object 11 is A cut surface of the object 11 when it is cut along line A by expanding is shown.
　図１３及び図１４において、「条件Ａ」は、「ラインＡ上の矢印で示される向き」（図１３では右向き、図１４では左向き）に集光スポットＣが相対的に移動させられ、その際に、集光スポットＣにおけるレーザ光Ｌのビーム形状９が、（１）「ラインＡ上に中心部９０及び第１延在部９１が位置し且つラインＡに対して第１の側（図１３では上側、図１４では下側）に第２延在部９２が位置し且つラインＡに対して第２の側（図１３では下側、図１４では上側）に第３延在部９３が位置する状態」となり、且つ、（２）「ラインＡに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置する状態」となるレーザ加工条件である。 13 and 14, "condition A" is that the condensed spot C is relatively moved in the "direction indicated by the arrow on line A" (rightward in FIG. 13, leftward in FIG. 14); , the beam shape 9 of the laser beam L at the focused spot C is such that (1) the center portion 90 and the first extension portion 91 are located on the line A, and the first side with respect to the line A (FIG. 13 The second extending portion 92 is located on the upper side in FIG. 14, and the lower side in FIG. and (2) the first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along the line A, and the second extension part 91 is located on the rear side in the direction. The laser processing conditions are such that the portion 92 and the third extension portion 93 are located.
　また、「条件Ｂ」は、「ラインＡ上の矢印で示される向き」（図１３では左向き、図１４では右向き）に集光スポットＣが相対的に移動させられ、その際に、集光スポットＣにおけるレーザ光Ｌのビーム形状９が、（１）「ラインＡ上に中心部９０及び第１延在部９１が位置し且つラインＡに対して第２の側（図１３では上側、図１４では下側）に第２延在部９２が位置し且つラインＡに対して第１の側（図１３では下側、図１４では上側）に第３延在部９３が位置する状態」となり、且つ、（３）「ラインＡに沿って集光スポットＣが相対的に移動する向きの後側に第１延在部９１が位置し且つ当該向きの前側に第２延在部９２及び第３延在部９３が位置する状態」となるレーザ加工条件である。 In addition, "Condition B" is such that the focused spot C is relatively moved in the "direction indicated by the arrow on line A" (leftward in FIG. 13, rightward in FIG. 14), and at that time, the focused spot The beam shape 9 of the laser beam L at C is as follows: 13, the second extending portion 92 is located on the lower side) and the third extending portion 93 is located on the first side (lower side in FIG. 13, upper side in FIG. and (3) "the first extension part 91 is located on the rear side in the direction in which the focused spot C moves relatively along the line A, and the second extension part 92 and the third extension part are located on the front side in the direction These are the laser processing conditions in which the extension portion 93 is positioned.
　なお、「条件Ａ」の段における「標準」は、変調パターンがトレフォイル収差パターンを含んでいない点のみが「条件Ａ」と相違するレーザ加工条件である。また、「条件Ｂ」の段における「標準」は、変調パターンがトレフォイル収差パターンを含んでいない点のみが「条件Ｂ」と相違するレーザ加工条件である。 Note that "Standard" in the "Condition A" column is a laser processing condition that differs from "Condition A" only in that the modulation pattern does not include a trefoil aberration pattern. Further, "Standard" in the "Condition B" stage is a laser processing condition that differs from "Condition B" only in that the modulation pattern does not include a trefoil aberration pattern.
　図１３及び図１４に示される対象物１１の切断面の状態から得られる知見について、図１５を参照しつつ説明する。 Knowledge obtained from the state of the cut surface of the object 11 shown in FIGS. 13 and 14 will be explained with reference to FIG. 15.
　まず、図１５に示されるように、ラインＡに沿って対象物１１に改質領域１２を形成すると共に、改質領域１２からレーザ光Ｌの入射方向（Ｚ方向）及びラインＡの延在方向（Ｘ方向）の両方向に平行な第１面Ｐ１に沿って対象物１１に亀裂１３を形成する場合において、レーザ光Ｌの入射方向における亀裂１３の幅を小さくするときには、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように（図１３及び図１４では「条件Ａ」及び「条件Ｂ」）、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させればよい。 First, as shown in FIG. 15, a modified region 12 is formed in the object 11 along a line A, and the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of the line A are When forming a crack 13 in the object 11 along the first surface P1 parallel to both directions (X direction), when reducing the width of the crack 13 in the incident direction of the laser beam L, a first The extension part 91 is located, the second extension part 92 is located on one side with respect to line A, and the third extension part 93 is located on the other side with respect to line A (FIG. 13). and "Condition A" and "Condition B" in FIG. 14), a modulation pattern including a trefoil aberration pattern may be displayed on the spatial light modulator 7.
　なお、図１３及び図１４に示される対象物１１の切断面において、レーザ光Ｌの入射方向における亀裂の幅が小さくなっていることは、左右方向に延在する黒色の筋が二列の改質領域（左右方向に延在する黒色の帯状領域）の間に形成されていることから分かる。その理由は、二列の改質領域の形成時に各改質領域から延在した亀裂が二列の改質領域の間で繋がっていない状態で、エキスパンドによる対象物１１の切断が実施された場合に、左右方向に延在する黒色の筋が形成され得るからである。 In addition, in the cut plane of the object 11 shown in FIGS. 13 and 14, the width of the crack in the incident direction of the laser beam L is small because the black streaks extending in the left and right direction are modified in two rows. This can be seen from the fact that it is formed between the dark areas (black band-shaped areas extending in the left-right direction). The reason for this is that when cutting the object 11 by expanding is performed in a state where the cracks extending from each modified region are not connected between the two rows of modified regions when two rows of modified regions are formed. This is because black streaks extending in the left-right direction may be formed.
　また、図１５に示されるように、ラインＡに沿って対象物１１に改質領域１２を形成すると共に、第１面Ｐ１に沿って対象物１１に亀裂１３を形成する場合において、レーザ光Ｌの入射方向における亀裂１３の幅だけでなく、レーザ光Ｌの入射方向における改質領域１２の幅も小さくし、且つ、ラインＡに対して亀裂１３が蛇行するのを抑制するときには、ラインＡに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置するように（図１３及び図１４では「条件Ａ」）、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させればよい。なお、図１３及び図１４に示される対象物１１の切断面において、ラインＡに対する亀裂１３の蛇行が抑制されていることは、二列の改質領域から上下方向に延在する黒色の筋（ツイストハックルと称される）が、「標準」及び「条件Ｂ」よりも「条件Ａ」において減少していることから分かる。 Further, as shown in FIG. 15, when forming the modified region 12 in the object 11 along the line A and also forming the crack 13 in the object 11 along the first surface P1, the laser beam L When reducing not only the width of the crack 13 in the incident direction of the laser beam L but also the width of the modified region 12 in the incident direction of the laser beam L and suppressing the meandering of the crack 13 with respect to the line A, The first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along the line, and the second extension part 92 and the third extension part 93 are located on the rear side in the direction. (“Condition A” in FIGS. 13 and 14), a modulation pattern including a trefoil aberration pattern may be displayed on the spatial light modulator 7. In addition, in the cut plane of the object 11 shown in FIGS. 13 and 14, the fact that the meandering of the crack 13 with respect to the line A is suppressed is indicated by the black streaks ( This can be seen from the fact that the amount of twist hackle (referred to as twist hackle) was decreased in "Condition A" compared to "Standard" and "Condition B".
　なお、ラインＡとして対象物１１に設定された第１ライン及び第２ラインのそれぞれに沿って集光スポットＣを相対的に移動させる場合において、第１ラインに沿って集光スポットＣを相対的に移動させる向きと、第２ラインに沿って集光スポットＣを相対的に移動させる向きとが異なるときには、第１ライン及び第２ラインのそれぞれに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置するように、空間光変調器７において、トレフォイル収差パターンを含む変調パターンの向きを切り替えればよい。 In addition, in the case where the focused spot C is relatively moved along each of the first line and the second line set on the object 11 as the line A, the focused spot C is relatively moved along the first line. When the direction in which the focused spot C is moved is different from the direction in which the focused spot C is relatively moved along the second line, the focused spot C is relatively moved along each of the first line and the second line. A trefoil aberration pattern is formed in the spatial light modulator 7 so that the first extension part 91 is located on the front side in the direction, and the second extension part 92 and the third extension part 93 are located on the rear side in the direction. What is necessary is to switch the direction of the included modulation pattern.
　また、図１５に示されるように、レーザ光Ｌの入射方向（Ｚ方向）における改質領域１２及び亀裂１３の少なくとも一方の幅を第１幅とする場合には、第１トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させ、当該少なくとも一方の幅を第１幅よりも小さい第２幅とする場合には、第１トレフォイル収差強度よりも強い第２トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させればよい。なお、図１５に示される例では、レーザ光Ｌの入射方向における改質領域１２及び亀裂１３のそれぞれの幅が、第１トレフォイル収差強度よりも第２トレフォイル収差強度において小さくなっている。 Further, as shown in FIG. 15, when the width of at least one of the modified region 12 and the crack 13 in the incident direction (Z direction) of the laser beam L is set as the first width, the trefoil with the first trefoil aberration strength is When a modulation pattern including an aberration pattern is displayed on the spatial light modulator 7 and at least one of the widths is a second width smaller than the first width, the second trefoil aberration intensity is stronger than the first trefoil aberration intensity. What is necessary is to display a modulation pattern including the trefoil aberration pattern on the spatial light modulator 7. In the example shown in FIG. 15, the widths of each of the modified region 12 and the crack 13 in the incident direction of the laser beam L are smaller at the second trefoil aberration intensity than at the first trefoil aberration intensity.
　次に、トレフォイル収差パターンを用いたレーザ加工方法によって形成される改質領域及び亀裂（改質領域の形成時に改質領域から延在する亀裂）の第２例について説明する。図１６及び図１７は、レーザ加工条件ごとの対象物１１の切断面の第２例を示す図である。図１６及び図１７には、「シリコンウェハである対象物１１の内部に、シリコンウェハの厚さ方向に並ぶ二列の改質領域がラインＡに沿って形成され、その後に、対象物１１がエキスパンドによってラインＡに沿って切断された場合」における対象物１１の切断面が示されている。 Next, a second example of a modified region and a crack (a crack extending from the modified region when the modified region is formed) formed by a laser processing method using a trefoil aberration pattern will be described. FIGS. 16 and 17 are diagrams showing second examples of cut surfaces of the object 11 for each laser processing condition. 16 and 17, "Two rows of modified regions lined up in the thickness direction of the silicon wafer are formed inside the object 11, which is a silicon wafer, along line A, and then the object 11 is A cut surface of the object 11 when it is cut along line A by expanding is shown.
　図１６及び図１７において、「条件Ｃ」は、「ラインＡ上の矢印で示される向き」（図１６では右向き、図１７では左向き）に集光スポットＣが相対的に移動させられ、その際に、集光スポットＣにおけるレーザ光Ｌのビーム形状９が、（４）「ラインＡ上に中心部９０が位置し且つラインＡに対して第１の側（図１６では上側、図１７では下側）に第１延在部９１が位置し且つラインＡに対して第２の側（図１６では下側、図１７では上側）に第２延在部９２及び第３延在部９３が位置する状態」となるレーザ加工条件である。 16 and 17, "Condition C" is such that the focused spot C is relatively moved in the "direction indicated by the arrow on line A" (toward the right in FIG. 16, to the left in FIG. 17); , the beam shape 9 of the laser beam L at the focused spot C is (4) "the center part 90 is located on the line A and the first side with respect to the line A (the upper side in FIG. 16, the lower side in FIG. 17)" The first extending part 91 is located on the side), and the second extending part 92 and the third extending part 93 are located on the second side with respect to the line A (lower side in FIG. 16, upper side in FIG. 17). These are the laser processing conditions that result in a state in which the
　また、「条件Ｄ」は、「ラインＡ上の矢印で示される向き」（図１６では左向き、図１７では右向き）に集光スポットＣが相対的に移動させられ、その際に、集光スポットＣにおけるレーザ光Ｌのビーム形状９が、（５）「ラインＡ上に中心部９０が位置し且つラインＡに対して第２の側（図１６では上側、図１７では下側）に第１延在部９１が位置し且つラインＡに対して第１の側（図１６では下側、図１７では上側）に第２延在部９２及び第３延在部９３が位置する状態」となるレーザ加工条件である。 In addition, "Condition D" is such that the focused spot C is relatively moved in the "direction indicated by the arrow on line A" (leftward in FIG. 16, rightward in FIG. 17), and at that time, the focused spot The beam shape 9 of the laser beam L at C is defined as (5) "The center part 90 is located on line A, and the first part is located on the second side with respect to line A (upper side in FIG. 16, lower side in FIG. A state in which the extension part 91 is located and the second extension part 92 and the third extension part 93 are located on the first side (lower side in FIG. 16, upper side in FIG. 17) with respect to line A. These are laser processing conditions.
　なお、「条件Ｃ」の段における「標準」は、変調パターンがトレフォイル収差パターンを含んでいない点のみが「条件Ｃ」と相違するレーザ加工条件である。また、「条件Ｄ」の段における「標準」は、変調パターンがトレフォイル収差パターンを含んでいない点のみが「条件Ｄ」と相違するレーザ加工条件である。 Note that "Standard" in the "Condition C" column is a laser processing condition that differs from "Condition C" only in that the modulation pattern does not include a trefoil aberration pattern. Further, "Standard" in the "Condition D" stage is a laser processing condition that differs from "Condition D" only in that the modulation pattern does not include a trefoil aberration pattern.
　図１６及び図１７に示される対象物１１の切断面の状態から得られる知見について、図１８及び図１９を参照しつつ説明する。 Knowledge obtained from the state of the cut surface of the object 11 shown in FIGS. 16 and 17 will be explained with reference to FIGS. 18 and 19.
　まず、図１８に示されるように、ラインＡに沿って対象物１１に改質領域１２を形成すると共に、改質領域１２からレーザ光Ｌの入射方向（Ｚ方向）及びラインＡの延在方向（Ｘ方向）の両方向に平行な第１面Ｐ１に対して傾斜する第２面Ｐ２に沿って対象物１１に亀裂１３を形成する場合において、レーザ光Ｌの入射側とは反対側の領域が第１面Ｐ１に垂直な方向（Ｙ方向）における一方の側（図１８では左側）に位置するように第２面Ｐ２が傾斜しているときには、ラインＡに対して一方の側（図１８では左側）に第１延在部９１が位置し且つラインＡに対して他方の側（図１８では右側）に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させればよい。 First, as shown in FIG. 18, a modified region 12 is formed in the object 11 along a line A, and the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of the line A are When forming a crack 13 in the object 11 along the second surface P2 that is inclined with respect to the first surface P1 that is parallel to both directions (X direction), the area on the opposite side to the incident side of the laser beam L is When the second surface P2 is inclined so as to be located on one side (the left side in FIG. 18) in the direction perpendicular to the first surface P1 (the Y direction), The Trefoil aberration pattern is such that the first extending part 91 is located on the left side) and the second extending part 92 and the third extending part 93 are located on the other side (right side in FIG. 18) with respect to the line A. What is necessary is to display a modulation pattern including the following on the spatial light modulator 7.
　また、図１９に示されるように、ラインＡに沿って対象物１１に改質領域１２を形成すると共に、改質領域１２からレーザ光Ｌの入射方向（Ｚ方向）及びラインＡの延在方向（Ｘ方向）の両方向に平行な第１面Ｐ１に対して傾斜する第２面Ｐ２に沿って対象物１１に亀裂１３を形成する場合において、レーザ光Ｌの入射側とは反対側の領域が第１面Ｐ１に垂直な方向（Ｙ方向）における他方の側（図１９では右側）に位置するように第２面Ｐ２が傾斜しているときには、ラインＡに対して他方の側（図１９では右側）に第１延在部９１が位置し且つラインＡに対して一方の側（図１９では左側）に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させればよい。 Further, as shown in FIG. 19, a modified region 12 is formed in the object 11 along line A, and the incident direction (Z direction) of the laser beam L from the modified region 12 and the extending direction of line A are When forming a crack 13 in the object 11 along the second surface P2 that is inclined with respect to the first surface P1 that is parallel to both directions (X direction), the area on the opposite side to the incident side of the laser beam L is When the second surface P2 is inclined so as to be located on the other side (the right side in FIG. 19) in the direction perpendicular to the first surface P1 (Y direction), The Trefoil aberration pattern is such that the first extending part 91 is located on the right side) and the second extending part 92 and the third extending part 93 are located on one side (left side in FIG. 19) with respect to the line A. What is necessary is to display a modulation pattern including the following on the spatial light modulator 7.
　なお、ラインＡとして対象物１１に設定された第１ライン及び第２ラインのそれぞれに沿って集光スポットＣを相対的に移動させる場合において、第１ラインに沿って集光スポットＣを相対的に移動させる向きと、第２ラインに沿って集光スポットＣを相対的に移動させる向きとが異なるときには、第１ライン及び第２ラインのそれぞれに対して一方の側に第１延在部９１が位置し且つ第１ライン及び第２ラインのそれぞれに対して他方の側に第２延在部９２及び第３延在部９３が位置するように、空間光変調器７において、トレフォイル収差パターンを含む変調パターンの向きを切り替えればよい。 In addition, in the case where the focused spot C is relatively moved along each of the first line and the second line set on the object 11 as the line A, the focused spot C is relatively moved along the first line. When the direction in which the focused spot C is moved is different from the direction in which the focused spot C is relatively moved along the second line, the first extension portion 91 is placed on one side with respect to each of the first line and the second line. In the spatial light modulator 7, a trefoil aberration pattern is formed such that What is necessary is to switch the direction of the included modulation pattern.
　また、図１８及び図１９に示されるように、第１面Ｐ１と第２面Ｐ２との間の角度（すなわち、第１面Ｐ１と第２面Ｐ２とが成す鋭角側の角度）を第１角度とする場合には、第１トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させ、当該角度を第１角度よりも大きい第２角度とする場合には、第１トレフォイル収差強度よりも強い第２トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させればよい。なお、図１６及び図１７に示される対象物１１の切断面において、トレフォイル収差強度が強くなるほど亀裂が傾斜する角度が大きくなっていることは、トレフォイル収差強度が強くなるほど黒色の領域が増加していることから分かる。図１６及び図１７に示される対象物１１の切断面は、黒色の領域が増加する側が紙面の手前側に位置するように傾斜している。
［レーザ加工方法の第１例］ Further, as shown in FIGS. 18 and 19, the angle between the first surface P1 and the second surface P2 (that is, the acute angle formed by the first surface P1 and the second surface P2) is When the angle is set as an angle, a modulation pattern including a trefoil aberration pattern with the first trefoil aberration intensity is displayed on the spatial light modulator 7, and when the angle is set as a second angle larger than the first angle, the first trefoil aberration intensity is The spatial light modulator 7 may display a modulation pattern including a trefoil aberration pattern having a second trefoil aberration intensity stronger than the trefoil aberration intensity. In addition, in the cut plane of the object 11 shown in FIGS. 16 and 17, the angle at which the crack inclines increases as the trefoil aberration strength increases. This is because the black area increases as the trefoil aberration strength increases. You can tell from the fact that The cut plane of the object 11 shown in FIGS. 16 and 17 is inclined so that the side where the black area increases is located on the near side of the page.
[First example of laser processing method]
　図２０は、レーザ加工方法の第１例が適用される対象物１１を示す図である。図２０に示されるように、対象物１１は、第１表面１１ａ及び第２表面１１ｂを有する半導体ウェハである。一例として、対象物１１は、シリコンウェハと、当該シリコンウェハの第１表面１１ａ側に形成された複数の機能素子（図示省略）と、を備えている。複数の機能素子は、対象物１１に形成されたノッチ１１ｃを基準として、第１表面１１ａに沿ってマトリックス状に配置されている。各機能素子は、例えば、フォトダイオード等の受光素子、レーザダイオード等の発光素子、メモリ等の回路素子等である。各機能素子は、複数の層がスタックされて三次元的に構成される場合もある。なお、対象物１１には、ノッチ１１ｃの替わりに、オリエンテーションフラットが形成されていてもよい。 FIG. 20 is a diagram showing an object 11 to which the first example of the laser processing method is applied. As shown in FIG. 20, the object 11 is a semiconductor wafer having a first surface 11a and a second surface 11b. As an example, the object 11 includes a silicon wafer and a plurality of functional elements (not shown) formed on the first surface 11a side of the silicon wafer. The plurality of functional elements are arranged in a matrix along the first surface 11a with a notch 11c formed in the object 11 as a reference. Each functional element is, for example, a light receiving element such as a photodiode, a light emitting element such as a laser diode, a circuit element such as a memory, and the like. Each functional element may be configured three-dimensionally by stacking a plurality of layers. Note that an orientation flat may be formed on the object 11 instead of the notch 11c.
　レーザ加工方法の第１例は、上述したレーザ加工装置１において実施される。レーザ加工方法の第１例では、図２０に示される対象物１１が、格子状に延在する複数の加工面Ｐ１０のそれぞれに沿って機能素子ごとに切断される。各加工面Ｐ１０は、第１表面１１ａ及び第２表面１１ｂに垂直な平面である。レーザ加工方法の第１例では、図２１の（ａ）及び（ｂ）に示されるように、加工面Ｐ１０が、レーザ光Ｌの入射方向（Ｚ方向）及びラインＡの延在方向（Ｘ方向）の両方向に平行な第１面Ｐ１に合わされた状態で、対象物１１の内部に、対象物１１の厚さ方向に並ぶ二列の改質領域１２がラインＡに沿って形成される。 A first example of the laser processing method is carried out in the laser processing apparatus 1 described above. In the first example of the laser processing method, the object 11 shown in FIG. 20 is cut into functional elements along each of a plurality of processing surfaces P10 extending in a grid pattern. Each processed surface P10 is a plane perpendicular to the first surface 11a and the second surface 11b. In the first example of the laser processing method, as shown in (a) and (b) of FIG. ), two rows of modified regions 12 aligned in the thickness direction of the object 11 are formed inside the object 11 along the line A.
　レーザ加工方法の第１例では、加工面Ｐ１０内において延在するラインＡに沿って対象物１１に改質領域１２を形成すると共に、第１面Ｐ１に沿って対象物１１に亀裂１３を形成したい。また、レーザ加工方法の第１例では、対象物１１が薄いため、レーザ光Ｌの入射方向における改質領域１２及び亀裂１３のそれぞれの幅を小さくし、且つ、ラインＡに対して亀裂１３が蛇行するのを抑制したい。 In the first example of the laser processing method, a modified region 12 is formed in the object 11 along a line A extending within the processing surface P10, and a crack 13 is formed in the object 11 along the first surface P1. I want to. In the first example of the laser processing method, since the object 11 is thin, the widths of the modified region 12 and the crack 13 in the direction of incidence of the laser beam L are made small, and the crack 13 is made small with respect to the line A. I want to suppress meandering.
　そこで、レーザ加工方法の第１例では、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように、且つ、ラインＡに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置するように、制御部６が、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。このとき、レーザ光Ｌの入射方向における改質領域１２及び亀裂１３のそれぞれの幅をより小さくしたい場合には、制御部６が、より強いトレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。続いて、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させた状態で、ラインＡに沿って集光スポットＣが相対的に移動するように、制御部６が、支持部２を駆動部４に駆動させる。以上の工程が全ての加工面Ｐ１０に対して実施された後に、例えば対象物１１の第２表面１１ｂに貼られたダイシングテープの拡張によって、図２０に示される対象物１１が機能素子ごとに切断される。 Therefore, in the first example of the laser processing method, the first extension part 91 is located on the line A, the second extension part 92 is located on one side with respect to the line A, and the second extension part 92 is located on the other side with respect to the line A. , and the first extending part 91 is located in the front side in the direction in which the focused spot C moves relatively along the line A, and The control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern so that the second extension part 92 and the third extension part 93 are located on the side. At this time, if it is desired to make each width of the modified region 12 and the crack 13 smaller in the incident direction of the laser beam L, the control unit 6 changes the modulation pattern including the trefoil aberration pattern with stronger trefoil aberration intensity to the spatial light. Displayed on the modulator 7. Next, with the modulation pattern including the trefoil aberration pattern displayed on the spatial light modulator 7, the control unit 6 controls the support unit 2 so that the focused spot C moves relatively along the line A. The drive section 4 is caused to drive. After the above steps have been performed on all processed surfaces P10, the object 11 shown in FIG. 20 is cut into functional elements by, for example, expanding the dicing tape attached to the second surface 11b of the object 11. be done.
　なお、レーザ加工方法の第１例では、レーザ光Ｌが対象物１１の第１表面１１ａ側から入射させられてもよいし、レーザ光Ｌが対象物１１の第２表面１１ｂ側から入射させられてもよい。また、一列の改質領域１２がラインＡに沿って対象物１１の内部に形成されてもよいし、対象物１１の厚さ方向に並ぶ三列以上の改質領域１２がラインＡに沿って対象物１１の内部に形成されてもよい。対象物１１の厚さ方向に並ぶ複数列の改質領域１２がラインＡに沿って対象物１１の内部に形成される場合、複数の集光スポットＣを有するようにレーザ光Ｌが空間光変調器７によって変調されて、一回のレーザ光Ｌのスキャン（ラインＡに沿ったレーザ光Ｌの相対的な移動）によって複数列の改質領域１２がラインＡに沿って対象物１１の内部に形成されてもよい。また、レーザ加工時に、レーザ光Ｌが入射させられる表面とは反対側の第１表面１１ａ又は第２表面１１ｂにダイシングテープが貼られていてもよいし、レーザ光Ｌが入射させられる第１表面１１ａ又は第２表面１１ｂに、レーザ光Ｌに対して透過性を有するダイシングテープが貼られていてもよい。また、レーザ加工後であってダイシングテープの拡張前に、対象物１１の第２表面１１ｂが研削されて、対象物１１が薄くされてもよい。その際に、対象物１１に形成された改質領域１２が除去されてもよい。 In the first example of the laser processing method, the laser beam L may be incident on the first surface 11a side of the object 11, or the laser beam L may be incident on the second surface 11b side of the object 11. You can. Furthermore, one row of modified regions 12 may be formed inside the object 11 along line A, or three or more rows of modified regions 12 lined up in the thickness direction of object 11 may be formed along line A. It may be formed inside the object 11. When a plurality of rows of modified regions 12 arranged in the thickness direction of the object 11 are formed inside the object 11 along the line A, the laser beam L is spatially modulated so as to have a plurality of focused spots C. Modulated by the device 7, a plurality of rows of modified regions 12 are created inside the object 11 along the line A by one scan of the laser beam L (relative movement of the laser beam L along the line A). may be formed. Further, during laser processing, a dicing tape may be attached to the first surface 11a or the second surface 11b opposite to the surface on which the laser beam L is incident, or the first surface on which the laser beam L is incident. A dicing tape that is transparent to the laser beam L may be attached to the first surface 11a or the second surface 11b. Furthermore, after the laser processing and before the expansion of the dicing tape, the second surface 11b of the object 11 may be ground to make the object 11 thinner. At that time, the modified region 12 formed in the object 11 may be removed.
　また、レーザ加工方法の第１例では、レーザ光Ｌの出射側の表面（図２１に示される例では、第２表面１１ｂ）に近い改質領域１２（以下、「第１改質領域」という）を形成する際に、第１改質領域からレーザ光Ｌの出射側の表面に亀裂１３が到達しないように第１改質領域を形成し、第１改質領域とレーザ光Ｌの入射側の表面（図２１に示される例では、第１表面１１ａ）との間に改質領域１２（以下、「第２改質領域」という）を形成する際に、第１改質領域と第２改質領域との間で亀裂１３を繋げると共に、第１改質領域からレーザ光Ｌの出射側の表面に亀裂１３を到達させてもよい（以下、「抜け光ダメージ抑制加工」という）。その場合において、第１改質領域を形成する際には、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように、制御部６が、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させ、第２改質領域を形成する際には、制御部６が、トレフォイル収差パターンを含まない変調パターン（或いは、第１改質領域を形成する際よりも弱いトレフォイル収差強度のトレフォイル収差パターンを含む変調パターン）を空間光変調器７に表示させることが好ましい。このようなレーザ加工法によれば、第１改質領域を形成する際にレーザ光Ｌの抜け光の散乱が抑制されるため、レーザ光Ｌの出射側の表面に抜け光によるダメージが生じるのを抑制することができる。それ以外にも、端面の品質を向上させることができ（すなわち、切断面の凹凸を低減することができ）、トレフォイル収差パターンを含む変調パターンを利用してツイストハックルを抑制することで、そのような効果を更に向上させることができる。 In addition, in the first example of the laser processing method, a modified region 12 (hereinafter referred to as "first modified region") near the surface on the emission side of the laser beam L (second surface 11b in the example shown in FIG. 21) ), the first modified region is formed so that the cracks 13 do not reach the surface on the emission side of the laser beam L from the first modified region, and the first modified region and the surface on the incidence side of the laser beam L are formed. (in the example shown in FIG. 21, the first surface 11a), when forming the modified region 12 (hereinafter referred to as "second modified region"), the first modified region and the second The cracks 13 may be connected to the modified region, and the cracks 13 may be made to reach the surface on the emission side of the laser beam L from the first modified region (hereinafter referred to as "light leakage damage suppression processing"). In that case, when forming the first modified region, the first extending portion 91 is located on the line A, the second extending portion 92 is located on one side with respect to the line A, and the first extending portion 91 is located on the line A. The control unit 6 causes the spatial light modulator 7 to display a modulation pattern including a trefoil aberration pattern so that the third extension part 93 is located on the other side with respect to A, thereby forming a second modified region. In this case, the control unit 6 transmits a modulation pattern that does not include a trefoil aberration pattern (or a modulation pattern that includes a trefoil aberration pattern having a weaker trefoil aberration intensity than when forming the first modified region) to the spatial light modulator 7. It is preferable to display the According to such a laser processing method, scattering of the passing light of the laser beam L is suppressed when forming the first modified region, so damage caused by the passing light is prevented from occurring on the surface on the emission side of the laser beam L. can be suppressed. Besides that, the quality of the end face can be improved (i.e., the unevenness of the cut surface can be reduced), and the twist hackle can be suppressed by utilizing a modulation pattern including a trefoil aberration pattern. The effects can be further improved.
　なお、第１改質領域を形成する際に、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように、且つ、ラインＡに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置するように、制御部６が、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させると、第１改質領域からレーザ光Ｌの出射側の表面に亀裂１３が到達するのをより確実に防止することができる。 Note that when forming the first modified region, the first extending portion 91 is located on line A, the second extending portion 92 is located on one side with respect to line A, and and the first extending part 91 is located in front of the direction in which the focused spot C moves relatively along the line A, and the third extending part 93 is located on the other side. When the control unit 6 causes the spatial light modulator 7 to display a modulation pattern including a trefoil aberration pattern so that the second extension part 92 and the third extension part 93 are located on the rear side, the first modification It is possible to more reliably prevent the cracks 13 from reaching the surface on the emission side of the laser beam L from the region.
　以上の知見は、対象物１１の厚さ方向に並ぶ「少なくとも一列の第１改質領域」及び「少なくとも一列の第２改質領域」をラインＡに沿って対象物１１の内部に形成する場合に適用可能である。なお、この場合において、第１改質領域の列数と第２改質領域の列数とは、互いに同じであってもよいし、互いに異なっていてもよい。 The above findings are applicable when forming "at least one row of first modified regions" and "at least one row of second modified regions" inside the target object 11 along line A in the thickness direction of the target object 11. Applicable to In this case, the number of rows of the first modified region and the number of rows of the second modified region may be the same or different.
　対象物１１の厚さ方向に並ぶ複数列の第１改質領域をラインＡに沿って対象物１１の内部に形成する場合には、レーザ加工に要する時間を短縮化するために（すなわち、いわゆるタクトアップのために）、複数の集光スポットＣを有するようにレーザ光Ｌが空間光変調器７によって変調されて、一回のレーザ光Ｌのスキャンによって複数列の第１改質領域がラインＡに沿って対象物１１の内部に形成されてもよい。この場合にも、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように、制御部６が、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。或いは、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように、且つ、ラインＡに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置するように、制御部６が、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。勿論、複数回のレーザ光Ｌのスキャンのそれぞれによって複数列の第１改質領域のそれぞれがラインＡに沿って対象物１１の内部に形成されてもよい。なお、一回のレーザ光Ｌのスキャンによって複数列の第１改質領域がラインＡに沿って対象物１１の内部に形成される場合にも、複数回のレーザ光Ｌのスキャンのそれぞれによって複数列の第１改質領域のそれぞれがラインＡに沿って対象物１１の内部に形成される場合にも、複数列の第１改質領域のそれぞれから伸びる亀裂は、互いに繋がらないことが好ましい。 When forming multiple rows of first modified regions in the thickness direction of the object 11 inside the object 11 along the line A, in order to shorten the time required for laser processing (i.e., the so-called In order to increase tact time), the laser beam L is modulated by the spatial light modulator 7 so as to have a plurality of focused spots C, and by one scan of the laser beam L, multiple rows of the first modified region are lined up. It may be formed inside the object 11 along A. Also in this case, the first extension part 91 is located on line A, the second extension part 92 is located on one side with respect to line A, and the third extension part 92 is located on the other side with respect to line A. The control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern so that the existing portion 93 is located. Alternatively, the first extending part 91 is located on line A, the second extending part 92 is located on one side with respect to line A, and the third extending part 93 is located on the other side with respect to line A. The first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along line A, and the second extension part 92 and The control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern so that the third extension portion 93 is located. Of course, a plurality of rows of first modified regions may be formed inside the object 11 along the line A by each scan of the laser beam L a plurality of times. Note that even when a plurality of rows of first modified regions are formed inside the object 11 along the line A by one scan of the laser beam L, a plurality of rows of first modified regions are formed by each of the plurality of scans of the laser beam L. Even when each of the first modified regions in the rows is formed inside the object 11 along the line A, it is preferable that the cracks extending from each of the first modified regions in the plurality of rows do not connect to each other.
　また、対象物１１の厚さ方向に並ぶ複数列の第２改質領域をラインＡに沿って対象物１１の内部に形成する場合には、タクトアップのために、複数の集光スポットＣを有するようにレーザ光Ｌが空間光変調器７によって変調されて、一回のレーザ光Ｌのスキャンによって複数列の第２改質領域がラインＡに沿って対象物１１の内部に形成されてもよい。勿論、対象物１１の厚さ方向に並ぶ複数列の第２改質領域をラインＡに沿って対象物１１の内部に形成する場合に、複数回のレーザ光Ｌのスキャンのそれぞれによって複数列の第２改質領域のそれぞれがラインＡに沿って対象物１１の内部に形成されてもよい。なお、一回のレーザ光Ｌのスキャンによって複数列の第２改質領域がラインＡに沿って対象物１１の内部に形成される場合にも、複数回のレーザ光Ｌのスキャンのそれぞれによって複数列の第２改質領域のそれぞれがラインＡに沿って対象物１１の内部に形成される場合にも、複数列の第２改質領域のそれぞれから伸びる亀裂は、互いに繋がることが好ましい。 Furthermore, when forming a plurality of rows of second modified regions in the thickness direction of the object 11 inside the object 11 along the line A, a plurality of focused spots C are formed in order to increase the takt time. Even if the laser beam L is modulated by the spatial light modulator 7 so that a plurality of rows of second modified regions are formed inside the object 11 along the line A by one scan of the laser beam L. good. Of course, when forming a plurality of rows of second modified regions arranged in the thickness direction of the object 11 inside the object 11 along the line A, the plural rows of second modified regions are formed by each of the plurality of scans of the laser beam L. Each of the second modified regions may be formed inside the object 11 along the line A. Note that even when a plurality of rows of second modified regions are formed inside the object 11 along the line A by one scan of the laser beam L, a plurality of rows of second modified regions are formed by each of the plurality of scans of the laser beam L. Even when each of the rows of second modified regions is formed inside the object 11 along line A, it is preferable that the cracks extending from each of the plurality of rows of second modified regions are connected to each other.
　図２２は、抜け光ダメージ抑制加工による対象物１１の切断面の例を示す図である。図２２の（ａ）及び（ｂ）に示される切断面の例は、対象物１１の厚さ方向に並ぶ「三列の第１改質領域」及び「三列の第２改質領域」をラインＡに沿って対象物１１の内部に形成することで、得られたものである。図２２の（ａ）及び（ｂ）のいずれにおいても、一回のレーザ光Ｌのスキャンによって三列の第１改質領域をラインＡに沿って対象物１１の内部に形成し、その後に、一回のレーザ光Ｌのスキャンによって三列の第２改質領域をラインＡに沿って対象物１１の内部に形成した。図２２の（ａ）では、三列の第１改質領域を形成する際に、トレフォイル収差パターンを含まない変調パターンを空間光変調器７に表示させた。図２２の（ｂ）では、三列の第１改質領域を形成する際に、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように、且つ、ラインＡに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させた。その結果、図２２の（ａ）では、三列の第１改質領域が形成されている領域において、ツイストハックルが発生し、亀裂の伸び方も安定しなかった。一方、図２２の（ｂ）では、三列の第１改質領域が形成されている領域において、ツイストハックルの発生が抑制され、亀裂の伸び方も安定した。
［レーザ加工方法の第２例］ FIG. 22 is a diagram illustrating an example of a cut surface of the object 11 obtained by processing to suppress damage caused by light leakage. The example of the cut plane shown in FIGS. 22(a) and (b) shows "three rows of first modified regions" and "three rows of second modified regions" arranged in the thickness direction of the object 11. This is obtained by forming it inside the object 11 along line A. In both (a) and (b) of FIG. 22, three rows of first modified regions are formed inside the object 11 along the line A by one scan of the laser beam L, and then, Three rows of second modified regions were formed inside the object 11 along the line A by one scan of the laser beam L. In FIG. 22(a), when forming three rows of first modified regions, a modulation pattern that does not include a trefoil aberration pattern is displayed on the spatial light modulator 7. In FIG. 22(b), when forming three rows of first modified regions, the first extending portion 91 is located on line A, and the second extending portion is located on one side with respect to line A. 92 and the third extension part 93 is located on the other side with respect to the line A, and the first extension part 93 is located on the front side in the direction in which the focused spot C moves relatively along the line A. A modulation pattern including a trefoil aberration pattern was displayed on the spatial light modulator 7 such that the existing portion 91 was located and the second extending portion 92 and the third extending portion 93 were located on the rear side in this direction. As a result, in FIG. 22(a), twist hackles occurred in the region where the three rows of first modified regions were formed, and the way the cracks grew was not stable. On the other hand, in FIG. 22(b), the occurrence of twist hackles was suppressed in the region where the three rows of first modified regions were formed, and the growth of cracks was also stabilized.
[Second example of laser processing method]
　図２３の（ａ）及び（ｂ）は、レーザ加工方法の第２例が適用される対象物１００を示す図である。図２３の（ａ）及び（ｂ）に示されるように、対象物１００は、対象物１１と、対象物１１とは別部材である対象物１１Ｒと、を備えている。各対象物１１，１１Ｒは、例えば、シリコンウェハである。対象物１１の第２表面１１ｂには、複数の機能素子（図示省略）を含むデバイス層１１０が形成されている。対象物１１Ｒの一方の表面には、複数の機能素子（図示省略）を含むデバイス層１１０Ｒが形成されている。デバイス層１１０とデバイス層１１０Ｒとは、互いに接合されている。 FIGS. 23A and 23B are diagrams showing an object 100 to which the second example of the laser processing method is applied. As shown in FIGS. 23A and 23B, the object 100 includes an object 11 and an object 11R that is a separate member from the object 11. Each target object 11, 11R is, for example, a silicon wafer. A device layer 110 including a plurality of functional elements (not shown) is formed on the second surface 11b of the object 11. A device layer 110R including a plurality of functional elements (not shown) is formed on one surface of the object 11R. The device layer 110 and the device layer 110R are bonded to each other.
　レーザ加工方法の第２例は、上述したレーザ加工装置１において実施される。レーザ加工方法の第２例では、図２３の（ａ）及び（ｂ）に示される対象物１１が、加工面Ｐ１１、加工面Ｐ１２、及び複数の加工面Ｐ１３のそれぞれに沿って切断され、対象物１１の外縁部分が除去される（トリミング加工）。加工面Ｐ１１は、Ｚ方向に平行な中心線を有する円柱面である。加工面Ｐ１２は、加工面Ｐ１１におけるデバイス層１１０側の端部からデバイス層１１０Ｒの外縁に向かって拡がる円錐台状のテーパ面である。複数の加工面Ｐ１３は、加工面Ｐ１１から対象物１１の外縁に延在する平面である。レーザ加工方法の第２例では、図２４の（ａ）及び（ｂ）に示されるように、加工面Ｐ１２が、レーザ光Ｌの入射方向（Ｚ方向）及びラインＡの延在方向（Ｘ方向）の両方向に平行な第１面Ｐ１に対して傾斜する第２面Ｐ２に合わされた状態で、対象物１１の内部のうち加工面Ｐ１２に沿った部分に、対象物１１の厚さ方向に並ぶ二列の改質領域１２がラインＡに沿って形成される。なお、レーザ加工方法の第２例では、加工面Ｐ１２内においてラインＡが円周状に延在することになるが、ラインＡが曲線である場合におけるラインＡの延在方向とは、当該曲線の接線方向を意味する。 A second example of the laser processing method is carried out in the laser processing apparatus 1 described above. In the second example of the laser processing method, the object 11 shown in FIGS. 23A and 23B is cut along each of the processing surface P11, the processing surface P12, and the plurality of processing surfaces P13, and The outer edge portion of the object 11 is removed (trimming process). The processed surface P11 is a cylindrical surface having a center line parallel to the Z direction. The processed surface P12 is a truncated conical tapered surface that expands from the end of the processed surface P11 on the device layer 110 side toward the outer edge of the device layer 110R. The plurality of processing surfaces P13 are planes extending from the processing surface P11 to the outer edge of the object 11. In the second example of the laser processing method, as shown in (a) and (b) of FIG. ), lined up in the thickness direction of the object 11 in a portion of the inside of the object 11 along the processing surface P12, aligned with the second surface P2 that is inclined with respect to the first surface P1 that is parallel to both directions. Two rows of modified regions 12 are formed along line A. In the second example of the laser processing method, the line A extends circumferentially within the processing surface P12, but when the line A is a curved line, the extending direction of the line A is defined as means the tangential direction.
　レーザ加工方法の第２例では、加工面Ｐ１２内において延在するラインＡに沿って対象物１１に改質領域１２を形成すると共に、第２面Ｐ２に沿って対象物１１に亀裂１３を形成したい。また、レーザ加工方法の第２例では、レーザ光Ｌの入射側とは反対側の領域が第１面Ｐ１に垂直な方向（Ｙ方向）における外側に位置するように第２面Ｐ２が傾斜している。 In the second example of the laser processing method, a modified region 12 is formed in the object 11 along the line A extending within the processing surface P12, and a crack 13 is formed in the object 11 along the second surface P2. I want to. In the second example of the laser processing method, the second surface P2 is inclined such that the region on the opposite side to the incident side of the laser beam L is located on the outside in the direction perpendicular to the first surface P1 (Y direction). ing.
　そこで、レーザ加工方法の第２例では、ラインＡに対して外側に第１延在部９１が位置し且つラインＡに対して内側に第２延在部９２及び第３延在部９３が位置するように、制御部６が、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。このとき、第１面Ｐ１と第２面Ｐ２との間の角度をより大きくしたい場合には、制御部６が、より強いトレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。続いて、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させた状態で、ラインＡに沿って集光スポットＣが相対的に移動するように、制御部６が、支持部２を駆動部４に駆動させる。続いて、加工面Ｐ１１、及び複数の加工面Ｐ１３のそれぞれに沿って、対象物１１の厚さ方向に並ぶ複数の改質領域１２が形成される。以上の工程が実施された後に、対象物１１の外縁部分が除去され、更に、対象物１１の第１表面１１ａの研磨によって、加工面Ｐ１１が設定されていた部分が除去される。
［作用及び効果］ Therefore, in the second example of the laser processing method, the first extension part 91 is located outside the line A, and the second extension part 92 and the third extension part 93 are located inside the line A. The control unit 6 causes the spatial light modulator 7 to display a modulation pattern including the trefoil aberration pattern. At this time, if it is desired to make the angle between the first surface P1 and the second surface P2 larger, the control unit 6 applies a modulation pattern including a trefoil aberration pattern with a stronger trefoil aberration intensity to the spatial light modulator 7. Display. Next, with the modulation pattern including the trefoil aberration pattern displayed on the spatial light modulator 7, the control unit 6 controls the support unit 2 so that the focused spot C moves relatively along the line A. The drive section 4 is caused to drive. Subsequently, a plurality of modified regions 12 arranged in the thickness direction of the object 11 are formed along each of the processed surface P11 and the plurality of processed surfaces P13. After the above steps are performed, the outer edge portion of the object 11 is removed, and the first surface 11a of the object 11 is polished to remove the portion where the processed surface P11 was set.
[Action and effect]
　レーザ加工装置１（及びレーザ加工装置１において実施されるレーザ光方法）では、集光スポットＣにおけるレーザ光Ｌのビーム形状９が、中心部９０並びに中心部９０から放射状に延在する第１延在部９１、第２延在部９２及び第３延在部９３を含み且つ中心部９０において最も高い強度を有する状態で、当該集光スポットＣが、対象物１１に設定されたラインＡに沿って相対的に移動させられる。このとき、ラインＡに対するビーム形状９の向き等を調整することで、対象物１１に形成される改質領域１２及び亀裂１３の少なくとも一方の状態を調整することができる。よって、レーザ加工装置１によれば、加工に応じて適切な改質領域１２及び亀裂１３を対象物１１に形成することができる。 In the laser processing device 1 (and the laser beam method implemented in the laser processing device 1), the beam shape 9 of the laser light L at the focused spot C has a center portion 90 and a first extension extending radially from the center portion 90. The focused spot C is located along the line A set on the object 11, including the existing part 91, the second extending part 92, and the third extending part 93, and having the highest intensity in the central part 90. can be moved relative to each other. At this time, by adjusting the direction of the beam shape 9 with respect to the line A, etc., the state of at least one of the modified region 12 and the crack 13 formed in the object 11 can be adjusted. Therefore, according to the laser processing apparatus 1, appropriate modified regions 12 and cracks 13 can be formed in the object 11 according to the processing.
　レーザ加工装置１では、ラインＡに沿って対象物１１に改質領域１２を形成すると共に、改質領域１２からレーザ光Ｌの入射方向及びラインＡの延在方向の両方向に平行な第１面Ｐ１に沿って対象物１１に亀裂１３を形成する場合には、制御部６が、ラインＡ上に第１延在部９１が位置し且つラインＡに対して一方の側に第２延在部９２が位置し且つラインＡに対して他方の側に第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。これにより、例えば変調パターンがトレフォイル収差パターンを含まない場合に比べ、レーザ光Ｌの入射方向における亀裂１３の幅を小さくすることができる。 In the laser processing apparatus 1, a modified region 12 is formed in the object 11 along the line A, and a first surface parallel to both the incident direction of the laser beam L and the extending direction of the line A is formed from the modified region 12. When forming a crack 13 in the object 11 along P1, the control unit 6 determines that the first extension part 91 is located on the line A and the second extension part is located on one side with respect to the line A. A modulation pattern including a trefoil aberration pattern is displayed on the spatial light modulator 7 such that the third extension part 93 is located on the other side with respect to the line A. Thereby, the width of the crack 13 in the incident direction of the laser beam L can be made smaller than, for example, when the modulation pattern does not include a trefoil aberration pattern.
　レーザ加工装置１では、制御部６が、ラインＡに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ向きの後側に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。これにより、レーザ光Ｌの入射方向における亀裂１３の幅だけでなく、レーザ光Ｌの入射方向における改質領域１２の幅も小さくすることができる。また、ラインＡに対して亀裂１３が蛇行するのを確実に抑制することができる。 In the laser processing apparatus 1, the control unit 6 is configured such that the first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along the line A, and the second extension part 91 is located on the rear side in the direction in which the focused spot C moves relatively along the line A. A modulation pattern including a trefoil aberration pattern is displayed on the spatial light modulator 7 such that the third extension portion 92 and the third extension portion 93 are located. Thereby, not only the width of the crack 13 in the incident direction of the laser beam L, but also the width of the modified region 12 in the incident direction of the laser beam L can be reduced. Moreover, meandering of the crack 13 with respect to the line A can be reliably suppressed.
　レーザ加工装置１では、ラインＡとして対象物１１に設定された第１ライン及び第２ラインのそれぞれに沿って集光スポットＣを相対的に移動させる場合において、第１ラインに沿って集光スポットＣを相対的に移動させる向きと、第２ラインに沿って集光スポットＣを相対的に移動させる向きとが異なるときには、制御部６が、第１ライン及び第２ラインのそれぞれに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンの向きを切り替える。これにより、第１ラインに沿って集光スポットＣを相対的に移動させる向きと、第２ラインに沿って集光スポットＣを相対的に移動させる向きとが異なる場合にも、第１ライン及び第２ラインのそれぞれに沿って集光スポットＣが相対的に移動する向きの前側に第１延在部９１が位置し且つ当該向きの後側に第２延在部９２及び第３延在部９３が位置する状態を容易に且つ確実に実現することができる。 In the laser processing device 1, when the focused spot C is relatively moved along each of the first line and the second line set on the object 11 as the line A, the focused spot C is moved along the first line. When the direction in which the focal spot C is relatively moved is different from the direction in which the focal spot C is relatively moved along the second line, the control unit 6 moves the focal spot C along the first line and the second line, respectively. Trefoil aberration is created such that the first extension part 91 is located on the front side in the direction in which the light spot C moves relatively, and the second extension part 92 and the third extension part 93 are located on the rear side in the direction. Switch the orientation of modulation patterns including patterns. As a result, even if the direction in which the focused spot C is relatively moved along the first line is different from the direction in which the focused spot C is relatively moved along the second line, the first line and The first extension part 91 is located on the front side in the direction in which the focused spot C moves relatively along each of the second lines, and the second extension part 92 and the third extension part are on the rear side in the direction. 93 can be easily and reliably realized.
　レーザ加工装置１では、制御部６が、レーザ光Ｌの入射方向における改質領域１２及び亀裂１３の少なくとも一方の幅を第１幅とする場合には、第１トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させ、当該少なくとも一方の幅を第１幅よりも小さい第２幅とする場合には、第１トレフォイル収差強度よりも強い第２トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。これにより、レーザ光Ｌの入射方向における改質領域１２及び亀裂１３の少なくとも一方の幅を、加工に応じて適切な幅にすることができる。 In the laser processing apparatus 1, when the control unit 6 sets the width of at least one of the modified region 12 and the crack 13 in the incident direction of the laser beam L as the first width, the controller 6 sets a trefoil aberration pattern with a first trefoil aberration intensity. When the spatial light modulator 7 displays a modulation pattern including a modulation pattern, and when at least one of the widths is a second width smaller than the first width, a trefoil aberration with a second trefoil aberration intensity stronger than the first trefoil aberration intensity. A modulation pattern including the pattern is displayed on the spatial light modulator 7. Thereby, the width of at least one of the modified region 12 and the crack 13 in the incident direction of the laser beam L can be set to an appropriate width depending on the processing.
　レーザ加工装置１では、ラインＡに沿って対象物１１に改質領域１２を形成すると共に、改質領域１２からレーザ光Ｌの入射方向及びラインＡの延在方向の両方向に平行な第１面Ｐ１に対して傾斜する第２面Ｐ２に沿って対象物１１に亀裂１３を形成する場合において、レーザ光Ｌの入射側とは反対側の領域が第１面Ｐ１に垂直な方向における一方の側に位置するように第２面Ｐ２が傾斜しているときには、制御部６が、ラインＡに対して一方の側に第１延在部９１が位置し且つラインＡに対して他方の側に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。これにより、改質領域１２から延在する亀裂１３を所望の側に傾斜させることができる。 In the laser processing apparatus 1, a modified region 12 is formed in the object 11 along the line A, and a first surface parallel to both the incident direction of the laser beam L and the extending direction of the line A is formed from the modified region 12. When forming a crack 13 in the object 11 along the second surface P2 that is inclined with respect to P1, the region opposite to the incident side of the laser beam L is on one side in the direction perpendicular to the first surface P1. When the second surface P2 is inclined so as to be located at A modulation pattern including a trefoil aberration pattern is displayed on the spatial light modulator 7 so that the second extension part 92 and the third extension part 93 are located. Thereby, the cracks 13 extending from the modified region 12 can be inclined to a desired side.
　レーザ加工装置１では、ラインＡとして対象物１１に設定された第１ライン及び第２ラインのそれぞれに沿って集光スポットＣを相対的に移動させる場合において、第１ラインに沿って集光スポットＣを相対的に移動させる向きと、第２ラインに沿って集光スポットＣを相対的に移動させる向きとが異なるときには、制御部６が、第１ライン及び第２ラインのそれぞれに対して一方の側に第１延在部９１が位置し且つ第１ライン及び第２ラインのそれぞれに対して他方の側に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンの向きを切り替える。これにより、第１ラインに沿って集光スポットＣを相対的に移動させる向きと、第２ラインに沿って集光スポットＣを相対的に移動させる向きとが異なる場合にも、第１ライン及び第２ラインのそれぞれに対して一方の側に第１延在部９１が位置し且つ第１ライン及び第２ラインのそれぞれに対して他方の側に第２延在部９２及び第３延在部９３が位置する状態を容易に且つ確実に実現することができる。 In the laser processing device 1, when the focused spot C is relatively moved along each of the first line and the second line set on the object 11 as the line A, the focused spot C is moved along the first line. When the direction in which the light spot C is relatively moved is different from the direction in which the focused spot C is relatively moved along the second line, the control unit 6 controls one direction for each of the first line and the second line. Trefoil aberration such that the first extending part 91 is located on the side of Switch the orientation of modulation patterns including patterns. As a result, even if the direction in which the focused spot C is relatively moved along the first line is different from the direction in which the focused spot C is relatively moved along the second line, the first line and A first extending portion 91 is located on one side with respect to each of the second lines, and a second extending portion 92 and a third extending portion are located on the other side with respect to each of the first line and the second line. 93 can be easily and reliably realized.
　レーザ加工装置１では、制御部６が、第１面Ｐ１と第２面Ｐ２との間の角度を第１角度とする場合には、第１トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させ、当該角度を第１角度よりも大きい第２角度とする場合には、第１トレフォイル収差強度よりも強い第２トレフォイル収差強度のトレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させる。これにより、改質領域１２から延在する亀裂１３が傾斜する角度を、加工に応じて適切な角度にすることができる。
［変形例］ In the laser processing apparatus 1, when the control unit 6 sets the angle between the first surface P1 and the second surface P2 as the first angle, the control unit 6 spatially modulates the modulation pattern including the trefoil aberration pattern with the first trefoil aberration intensity. When displaying on the optical modulator 7 and making the angle a second angle larger than the first angle, a modulation pattern including a trefoil aberration pattern with a second trefoil aberration intensity stronger than the first trefoil aberration intensity is displayed on the spatial light. Displayed on the modulator 7. Thereby, the angle at which the cracks 13 extending from the modified region 12 are inclined can be set to an appropriate angle depending on the processing.
[Modified example]
　本開示は、上記実施形態に限定されない。例えば、空間光変調器７は、反射型に限定されず、透過型であってもよい。また、空間光変調器７の変調面７ａでのレーザ光Ｌの像を集光部３３の入射瞳面３３ａに転像する光学系は、一対のレンズ３４Ａ，３４Ｂを有する４ｆレンズユニット３４に限定されず、空間光変調器７側の第１レンズ系（例えば、接合レンズ、三つ以上のレンズ等）及び集光部３３側の第２レンズ系（例えば、接合レンズ、三つ以上のレンズ等）を含むもの等であってもよい。 The present disclosure is not limited to the above embodiments. For example, the spatial light modulator 7 is not limited to a reflective type, but may be a transmissive type. Further, the optical system that transfers the image of the laser beam L on the modulation surface 7a of the spatial light modulator 7 to the entrance pupil plane 33a of the condenser 33 is limited to the 4f lens unit 34 having a pair of lenses 34A and 34B. The first lens system (for example, a cemented lens, three or more lenses, etc.) on the spatial light modulator 7 side and the second lens system (for example, a cemented lens, three or more lenses, etc.) on the condensing section 33 side ).
　また、上記実施形態では、駆動部４が支持部２を駆動するものであり、駆動部５が照射部３を駆動することで集光部３３を駆動するものであったが、本開示の駆動部は、そのようなものに限定されない。一例として、駆動部４が、Ｚ方向、Ｘ方向及びＹ方向のそれぞれの方向に支持部２を移動させ、Ｚ方向に平行な軸線を回転軸として支持部２を回転させてもよい。或いは、駆動部５が、Ｚ方向、Ｘ方向及びＹ方向のそれぞれの方向に集光部３３を移動させ、Ｚ方向に平行な軸線を中心線として集光部３３を移動させてもよい。つまり、本開示の駆動部は、支持部及び集光部の少なくとも一方を駆動するものであればよい。 Further, in the embodiment described above, the drive section 4 drives the support section 2, and the drive section 5 drives the light collecting section 33 by driving the irradiation section 3, but the drive section of the present disclosure The section is not limited to such. As an example, the drive unit 4 may move the support unit 2 in each of the Z direction, the X direction, and the Y direction, and rotate the support unit 2 using an axis parallel to the Z direction as the rotation axis. Alternatively, the drive section 5 may move the light condensing section 33 in each of the Z direction, the X direction, and the Y direction, and may move the light condensing section 33 with an axis parallel to the Z direction as the center line. That is, the drive unit of the present disclosure may be any drive unit that drives at least one of the support unit and the light condensing unit.
　また、上記実施形態では、制御部６が、支持部２、照射部３及び駆動部４，５を制御するものであったが、本開示の制御部は、そのようなものに限定されない。本開示の制御部は、少なくとも空間光変調器及び駆動部を制御するものであればあればよい。 Furthermore, in the embodiment described above, the control unit 6 controls the support unit 2, the irradiation unit 3, and the drive units 4 and 5, but the control unit of the present disclosure is not limited to such a unit. The control unit of the present disclosure may be any unit as long as it controls at least the spatial light modulator and the drive unit.
　また、ラインＡに対して一方の側に第１延在部９１が位置し且つラインＡに対して他方の側に第２延在部９２及び第３延在部９３が位置するように、トレフォイル収差パターンを含む変調パターンを空間光変調器７に表示させるレーザ加工方法は、ウェハを複数の四角錘台状のチップに切断する場合、ウェハから複数の円錐台状のウェハを切り出す場合等にも有効である。 Further, the Trefoil is arranged such that the first extending portion 91 is located on one side with respect to line A, and the second extending portion 92 and third extending portion 93 are located on the other side with respect to line A. The laser processing method of displaying a modulation pattern including an aberration pattern on the spatial light modulator 7 can also be used when cutting a wafer into a plurality of square pyramid-shaped chips, cutting out a plurality of truncated cone-shaped wafers from a wafer, etc. It is valid.
　１…レーザ加工装置、２…支持部、４，５…駆動部、６…制御部、７…空間光変調器、９…ビーム形状、１１…対象物、１２…改質領域、１３…亀裂、３１…光源、３３…集光部、９０…中心部、９１…第１延在部、９２…第２延在部、９３…第３延在部、Ａ…ライン、Ｃ…集光スポット、Ｌ…レーザ光、Ｐ１…第１面、Ｐ２…第２面。

  DESCRIPTION OF SYMBOLS 1... Laser processing device, 2... Support part, 4, 5... Drive part, 6... Control part, 7... Spatial light modulator, 9... Beam shape, 11... Target object, 12... Modified region, 13... Crack, 31...Light source, 33...Condensing part, 90...Central part, 91...First extension part, 92...Second extension part, 93...Third extension part, A...Line, C...Condensing spot, L ...Laser light, P1...first surface, P2...second surface.

Claims (9)

  1. 　対象物を支持する支持部と、
    　レーザ光を出射する光源と、
    　変調パターンを表示することで、前記光源から出射された前記レーザ光を変調する空間光変調器と、
    　前記空間光変調器によって変調された前記レーザ光を前記対象物に集光する集光部と、
    　前記支持部及び前記集光部の少なくとも一方を駆動する駆動部と、
    　少なくとも前記空間光変調器及び前記駆動部を制御する制御部と、を備え、
    　前記制御部は、
    　前記レーザ光の集光スポットにおける前記レーザ光のビーム形状が、中心部並びに前記中心部から放射状に延在する第１延在部、第２延在部及び第３延在部を含み且つ前記中心部において最も高い強度を有するビーム形状となるように、トレフォイル収差パターンを含む変調パターンを前記空間光変調器に表示させ、
    　前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させた状態で、前記対象物に設定されたラインに沿って前記集光スポットが相対的に移動するように、前記支持部及び前記集光部の少なくとも一方を前記駆動部に駆動させる、レーザ加工装置。     a support part that supports the object;
    a light source that emits laser light;
    a spatial light modulator that modulates the laser light emitted from the light source by displaying a modulation pattern;
    a condensing unit that condenses the laser beam modulated by the spatial light modulator on the object;
    a driving section that drives at least one of the support section and the light condensing section;
    a control unit that controls at least the spatial light modulator and the drive unit,
    The control unit includes:
    The beam shape of the laser beam at the focused spot of the laser beam includes a center portion, a first extending portion, a second extending portion, and a third extending portion extending radially from the center portion, and displaying a modulation pattern including a trefoil aberration pattern on the spatial light modulator so as to have a beam shape having the highest intensity in the region;
    The supporting portion and A laser processing device that causes the driving section to drive at least one of the light condensing sections.
  2. 　前記ラインに沿って前記対象物に改質領域を形成すると共に、前記改質領域から前記レーザ光の入射方向及び前記ラインの延在方向の両方向に平行な第１面に沿って前記対象物に亀裂を形成する場合には、
    　前記制御部は、前記ライン上に前記第１延在部が位置し且つ前記ラインに対して一方の側に前記第２延在部が位置し且つ前記ラインに対して他方の側に前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、請求項１に記載のレーザ加工装置。     Forming a modified region on the object along the line, and forming a modified region on the object along a first surface parallel to both the incident direction of the laser beam and the extending direction of the line from the modified region. When cracks form,
    The control unit is configured such that the first extension part is located on the line, the second extension part is located on one side with respect to the line, and the third extension part is located on the other side with respect to the line. The laser processing apparatus according to claim 1, wherein the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator so that the extension portion is located.
  3. 　前記制御部は、前記ラインに沿って前記集光スポットが相対的に移動する向きの前側に前記第１延在部が位置し且つ前記向きの後側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、請求項２に記載のレーザ加工装置。 The control unit is configured such that the first extension part is located on the front side in a direction in which the focused spot moves relatively along the line, and the second extension part and the third extension part are located on the rear side in the direction. The laser processing apparatus according to claim 2, wherein the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator so that the extension portion is located.
  4. 　前記ラインとして前記対象物に設定された第１ライン及び第２ラインのそれぞれに沿って前記集光スポットを相対的に移動させる場合において、前記第１ラインに沿って前記集光スポットを相対的に移動させる向きと、前記第２ラインに沿って前記集光スポットを相対的に移動させる向きとが異なるときには、
    　前記制御部は、前記第１ライン及び前記第２ラインのそれぞれに沿って前記集光スポットが相対的に移動する向きの前側に前記第１延在部が位置し且つ前記向きの後側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンの向きを切り替える、請求項３に記載のレーザ加工装置。     In the case where the focused spot is relatively moved along each of a first line and a second line set on the object as the line, the focused spot is moved relatively along the first line. When the direction of movement and the direction of relative movement of the focused spot along the second line are different,
    The control unit is arranged such that the first extension part is located on the front side in a direction in which the focused spot moves relatively along each of the first line and the second line, and the first extension part is located on the rear side in the direction in which the focused spot moves relatively. The laser processing apparatus according to claim 3, wherein the direction of the modulation pattern including the trefoil aberration pattern is switched so that the second extension part and the third extension part are located.
  5. 　前記制御部は、
    　前記レーザ光の前記入射方向における前記改質領域及び前記亀裂の少なくとも一方の幅を第１幅とする場合には、第１トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させ、
    　前記少なくとも一方の幅を前記第１幅よりも小さい第２幅とする場合には、前記第１トレフォイル収差強度よりも強い第２トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、請求項２～４のいずれか一項に記載のレーザ加工装置。     The control unit includes:
    When the width of at least one of the modified region and the crack in the incident direction of the laser beam is a first width, the modulation pattern including the trefoil aberration pattern having a first trefoil aberration intensity is used for the spatial light modulation. display it on the device,
    When the at least one width is a second width smaller than the first width, the modulation pattern including the trefoil aberration pattern having a second trefoil aberration intensity stronger than the first trefoil aberration intensity is used as the spatial light. The laser processing device according to any one of claims 2 to 4, which is displayed on a modulator.
  6. 　前記ラインに沿って前記対象物に改質領域を形成すると共に、前記改質領域から前記レーザ光の入射方向及び前記ラインの延在方向の両方向に平行な第１面に対して傾斜する第２面に沿って前記対象物に亀裂を形成する場合において、前記レーザ光の入射側とは反対側の領域が前記第１面に垂直な方向における一方の側に位置するように前記第２面が傾斜しているときには、
    　前記制御部は、前記ラインに対して前記一方の側に前記第１延在部が位置し且つ前記ラインに対して他方の側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、請求項１に記載のレーザ加工装置。     A modified region is formed in the object along the line, and a second surface is inclined from the modified region to the first surface parallel to both the incident direction of the laser beam and the extending direction of the line. In the case where a crack is formed in the object along a surface, the second surface is arranged such that a region opposite to the incident side of the laser beam is located on one side in a direction perpendicular to the first surface. When it's tilted,
    The control unit is configured such that the first extension part is located on the one side with respect to the line, and the second extension part and the third extension part are located on the other side with respect to the line. The laser processing apparatus according to claim 1, wherein the modulation pattern including the trefoil aberration pattern is displayed on the spatial light modulator.
  7. 　前記ラインとして前記対象物に設定された第１ライン及び第２ラインのそれぞれに沿って前記集光スポットを相対的に移動させる場合において、前記第１ラインに沿って前記集光スポットを相対的に移動させる向きと、前記第２ラインに沿って前記集光スポットを相対的に移動させる向きとが異なるときには、
    　前記制御部は、前記第１ライン及び前記第２ラインのそれぞれに対して前記一方の側に前記第１延在部が位置し且つ前記第１ライン及び前記第２ラインのそれぞれに対して他方の側に前記第２延在部及び前記第３延在部が位置するように、前記トレフォイル収差パターンを含む前記変調パターンの向きを切り替える、請求項６に記載のレーザ加工装置。     In the case where the focused spot is relatively moved along each of a first line and a second line set on the object as the line, the focused spot is moved relatively along the first line. When the direction of movement and the direction of relative movement of the focused spot along the second line are different,
    The control unit is configured such that the first extension portion is located on the one side with respect to each of the first line and the second line, and the first extension portion is located on the other side with respect to each of the first line and the second line. The laser processing apparatus according to claim 6, wherein the direction of the modulation pattern including the trefoil aberration pattern is switched so that the second extension part and the third extension part are located on the side.
  8. 　前記制御部は、
    　前記第１面と前記第２面との間の角度を第１角度とする場合には、第１トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させ、
    　前記角度を前記第１角度よりも大きい第２角度とする場合には、前記第１トレフォイル収差強度よりも強い第２トレフォイル収差強度の前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させる、請求項６又は７に記載のレーザ加工装置。     The control unit includes:
    When the angle between the first surface and the second surface is a first angle, displaying the modulation pattern including the trefoil aberration pattern with a first trefoil aberration intensity on the spatial light modulator;
    When the angle is a second angle larger than the first angle, the modulation pattern including the trefoil aberration pattern having a second trefoil aberration intensity stronger than the first trefoil aberration intensity is applied to the spatial light modulator. The laser processing device according to claim 6 or 7, wherein the laser processing device displays the information.
  9. 　対象物を支持する支持部と、
    　レーザ光を出射する光源と、
    　変調パターンを表示することで、前記光源から出射された前記レーザ光を変調する空間光変調器と、
    　前記空間光変調器によって変調された前記レーザ光を前記対象物に集光する集光部と、
    　前記支持部及び前記集光部の少なくとも一方を駆動する駆動部と、を備えるレーザ加工装置において実施されるレーザ加工方法であって、
    　前記レーザ光の集光スポットにおける前記レーザ光のビーム形状が、中心部並びに前記中心部から放射状に延在する第１延在部、第２延在部及び第３延在部を含み且つ前記中心部において最も高い強度を有するビーム形状となるように、トレフォイル収差パターンを含む変調パターンを前記空間光変調器に表示させる工程と、
    　前記トレフォイル収差パターンを含む前記変調パターンを前記空間光変調器に表示させた状態で、前記対象物に設定されたラインに沿って前記集光スポットが相対的に移動するように、前記支持部及び前記集光部の少なくとも一方を前記駆動部に駆動させる工程と、を備える、レーザ加工方法。

          a support part that supports the object;
    a light source that emits laser light;
    a spatial light modulator that modulates the laser light emitted from the light source by displaying a modulation pattern;
    a condensing unit that condenses the laser beam modulated by the spatial light modulator on the object;
    A laser processing method carried out in a laser processing apparatus including a driving section that drives at least one of the support section and the light condensing section,
    The beam shape of the laser beam at the focused spot of the laser beam includes a center portion, a first extending portion, a second extending portion, and a third extending portion extending radially from the center portion, and displaying a modulation pattern including a trefoil aberration pattern on the spatial light modulator so as to have a beam shape having the highest intensity in the spatial light modulator;
    The supporting portion and A laser processing method, comprising the step of causing the driving section to drive at least one of the light condensing sections.
PCT/JP2023/028946 2022-09-13 2023-08-08 Laser processing device, and laser processing method WO2024057780A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021087974A (en) * 2019-12-04 2021-06-10 浜松ホトニクス株式会社 Laser processing device
JP2021090990A (en) * 2019-12-11 2021-06-17 株式会社ディスコ Correction method of spot shape of laser beam
JP2022029227A (en) * 2020-08-04 2022-02-17 株式会社ディスコ Laser processing device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021087974A (en) * 2019-12-04 2021-06-10 浜松ホトニクス株式会社 Laser processing device
JP2021090990A (en) * 2019-12-11 2021-06-17 株式会社ディスコ Correction method of spot shape of laser beam
JP2022029227A (en) * 2020-08-04 2022-02-17 株式会社ディスコ Laser processing device

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