WO2022254844A1 - レーザ加工装置 - Google Patents

レーザ加工装置 Download PDF

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Publication number
WO2022254844A1
WO2022254844A1 PCT/JP2022/009218 JP2022009218W WO2022254844A1 WO 2022254844 A1 WO2022254844 A1 WO 2022254844A1 JP 2022009218 W JP2022009218 W JP 2022009218W WO 2022254844 A1 WO2022254844 A1 WO 2022254844A1
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WO
WIPO (PCT)
Prior art keywords
unit
laser
laser beam
displacement information
light
Prior art date
Application number
PCT/JP2022/009218
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English (en)
French (fr)
Japanese (ja)
Inventor
克洋 是松
哲也 飯田
Original Assignee
浜松ホトニクス株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 浜松ホトニクス株式会社 filed Critical 浜松ホトニクス株式会社
Priority to JP2023525405A priority Critical patent/JPWO2022254844A1/ja
Priority to KR1020237027903A priority patent/KR20240015615A/ko
Priority to CN202280039414.8A priority patent/CN117412830A/zh
Publication of WO2022254844A1 publication Critical patent/WO2022254844A1/ja

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes
    • G01B11/27—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes
    • G01B11/272—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes using photoelectric detection means
    • 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
    • B23K26/03—Observing, e.g. monitoring, the workpiece
    • B23K26/032—Observing, e.g. monitoring, the workpiece using optical means
    • 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
    • B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
    • B23K26/046—Automatically focusing the laser beam
    • 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
    • B23K26/0648—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses
    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques

Definitions

  • This disclosure relates to a laser processing apparatus.
  • a laser processing apparatus that forms a modified region by irradiating an object with a laser beam is known (see Patent Document 1, for example).
  • Such a laser processing apparatus includes a support section that supports an object, an irradiation section that irradiates the object with laser light through a condenser lens, and a condenser lens that moves along the optical axis direction of the condenser lens. and an imaging unit that captures an image of the laser beam incident surface of the object.
  • the reticle is projected onto the laser beam irradiation surface of the object, and the moving mechanism is operated so that the reticle is focused on the image captured by the imaging unit.
  • alignment is performed in which the position of the condenser lens with respect to the surface in the optical axis direction is aligned with the reference position.
  • the reticle cannot be correctly identified on the image, which may make it difficult to align the condenser lens. have a nature.
  • an object of the present disclosure is to provide a laser processing apparatus capable of aligning the position of the condenser lens with respect to the laser light incident surface in the optical axis direction regardless of the object.
  • a laser processing apparatus is a laser processing apparatus that irradiates an object with a laser beam to form a modified region, and includes a support that supports the object and a condenser lens that is attached to the object. a moving mechanism for moving the condenser lens along the optical axis direction of the condenser lens; an imaging part for imaging the laser beam incidence surface of the object; and a displacement information acquisition unit that acquires displacement information that changes according to the displacement of the laser light incident surface, and the position of the condenser lens with respect to the laser light incident surface in the optical axis direction based on the imaging result of the imaging unit.
  • a first positioning unit that operates the moving mechanism so as to match the position or a predetermined height position that is a predetermined distance from the reference position;
  • An information recording unit that records the displacement information acquired by the displacement information acquisition unit when it is aligned with the height position as reference displacement information, and a movement so that the displacement information acquired by the displacement information acquisition unit becomes the reference displacement information.
  • a second alignment unit that operates the mechanism to align the position of the condenser lens in the optical axis direction with respect to the laser beam incident surface to the reference position or the predetermined height position.
  • the first alignment unit aligns the position of the condenser lens with respect to the laser beam incident surface of the object in the optical axis direction (hereinafter referred to as such alignment) based on the imaging result of the imaging unit. is also called “height set").
  • the displacement information acquired by the displacement information acquiring section at this time is recorded as the reference displacement information by the information recording section.
  • height setting can be performed by operating the movement mechanism using the reference displacement information by the second alignment unit. That is, according to one aspect of the present disclosure, both functions of height setting by the first alignment unit and height setting by the second alignment unit are provided, so that height setting can be performed regardless of the object. It becomes possible.
  • the imaging unit receives visible light that enters the laser light entrance surface via the reticle and is reflected by the laser light entrance surface, and the reference position is captured by the imaging unit. It may be the position of the condensing lens when the reticle is focused on the image on the laser light incident surface. In this case, height setting can be performed using the reticle by the first alignment unit.
  • processing by the first alignment unit is executed, and when the state of the reticle being focused on the image of the laser light incident surface captured by the imaging unit cannot be recognized, the reference displacement information is not recorded by the information recording unit, a processing impossibility determination unit may be provided that determines that the target object cannot be processed. Accordingly, it can be determined that the object cannot be processed because height setting cannot be performed.
  • processing by the first alignment unit is executed, and when the state of the reticle being focused on the image of the laser light incident surface captured by the imaging unit cannot be recognized, the reference displacement information is recorded by the information recording unit, a switching unit that causes the second alignment unit to perform processing may be provided.
  • the height setting by the first alignment unit is preferentially executed, and if the height setting by the first alignment unit is impossible, it is possible to switch to the height setting by the second alignment unit.
  • the displacement information acquisition unit includes a light-emitting element that emits measurement laser light, and a light-receiving element array that receives the measurement laser light reflected by the laser light incident surface.
  • the displacement information that changes according to the displacement of the laser light incident surface may correspond to the light receiving position of the measurement laser light in the light receiving element array.
  • height setting can be performed using the light receiving position of the measurement laser light in the light receiving element array as the displacement information.
  • the displacement information acquisition unit includes a light-emitting element that emits measurement laser light, and the measurement laser light reflected by the laser light incident surface, and branches the measurement laser light into a plurality of branch measurement laser lights. and a light-receiving element array for receiving a plurality of branching measurement laser beams. Displacement information that changes in accordance with the displacement of the laser light incident surface is obtained from the plurality of branching measurement laser beams in the light-receiving element array. may correspond to the interval of the light receiving positions. In this case, height setting can be performed using the distance between the light receiving positions of the laser beams for branch measurement in the light receiving element array as the displacement information.
  • a laser processing apparatus may include a received light amount adjustment unit that adjusts the displacement information acquisition unit so that the amount of received light in the light receiving element array is equal to or greater than the threshold. In this case, it is possible to prevent the inability to acquire effective displacement information due to a small amount of light received by the light receiving element array.
  • a laser processing apparatus may include a reference support section that supports a reference object that does not include a film or tape material on the laser light incident surface side.
  • the first positioning unit performs height setting on the reference object supported by the reference support unit, and the displacement information acquired at this time is recorded as the reference displacement information by the information recording unit. can.
  • the displacement information acquired by the displacement information acquisition unit becomes the reference displacement information.
  • the movement mechanism may be operated so that the position of the condenser lens with respect to the laser light incident surface in the optical axis direction matches the reference position based on the imaging result of the imaging unit. In this case, it is possible to speed up the height setting by the first alignment unit (that is, the height setting based on the imaging result of the imaging unit).
  • the displacement information acquisition unit emits the measurement laser beam to the laser beam entrance surface and receives the measurement laser beam reflected by the laser beam entrance surface.
  • the second alignment unit Based on the transmission member information including information on the thickness and refractive index of the transmission member, the shift of the optical path of the measurement laser light with the transmission member with respect to the optical path of the measurement laser light without the transmission member is handled.
  • the offset amount may be calculated, and the reference displacement information pre-stored in the information recording unit may be changed based on the calculated offset amount. This makes it possible to deal with an object having a transmissive member (for example, a transparent tape, etc.) on the laser light incident surface.
  • a laser processing apparatus includes an input unit that receives input regarding the presence or absence of a transparent member and information on the transparent member, and the second alignment unit determines whether or not there is a transparent member based on an input from the input unit. If it is determined that there is a transmissive member, the offset amount may be calculated. This makes it possible to use the input from the input section to deal with an object having a transmission member provided on the laser light incident surface.
  • the present disclosure it is possible to provide a laser processing apparatus capable of aligning the position of the condenser lens with respect to the laser light incident surface in the optical axis direction regardless of the object.
  • FIG. 1 is a perspective view showing a laser processing device according to an embodiment.
  • FIG. 2 is a perspective view of an object attached to a support base of the laser processing apparatus according to the embodiment; 3 is a cross-sectional view along the XY plane of FIG. 1.
  • FIG. FIG. 4 is a perspective view showing part of a laser output section and a laser condensing section of the laser processing apparatus according to the embodiment.
  • 5 is a cross-sectional view along the XY plane of FIG. 1.
  • FIG. FIG. 6 is a cross-sectional view along line VI-VI of FIG.
  • FIG. 7 is a cross-sectional view along line VII--VII of FIG.
  • FIG. 8 is a front view showing a schematic configuration of another axis ranging sensor according to the embodiment.
  • FIG. 1 is a perspective view showing a laser processing device according to an embodiment.
  • FIG. 2 is a perspective view of an object attached to a support base of the laser processing apparatus according to the embodiment
  • 3 is
  • FIG. 9 is a diagram showing a state in which the marks of the reticle are in focus in the image of the laser light incident surface captured by the observation camera according to the embodiment.
  • FIG. 10 is a flowchart illustrating an example of height setting.
  • FIG. 11 is a flowchart illustrating an example of height setting.
  • FIG. 12(a) is a front view of another axis ranging sensor for explaining the height setting.
  • FIG. 12(b) is a front view of another axial distance measuring sensor showing a continuation of FIG. 12(a).
  • FIG. 13 is a diagram showing a state in which the reticle mark is not visible in the image of the laser light incident surface captured by the observation camera according to the embodiment.
  • FIG. 14 is a flowchart illustrating an example of height setting.
  • FIG. 14 is a flowchart illustrating an example of height setting.
  • FIG. 15 is a flowchart illustrating an example of height setting.
  • FIG. 16 is a schematic plan view showing a support base and a reference support base of a laser processing apparatus according to a modification.
  • 17 is a schematic plan view showing a state in which the target object and the reference target object are supported by the support base and the reference support base of FIG. 16;
  • FIG. 18A is a flowchart showing an example of height setting.
  • FIG. 18B is a flowchart showing an example of height setting.
  • FIG. 19 is a flowchart illustrating an example of height setting.
  • FIG. 20(a) is a diagram showing a schematic configuration of a different-axis ranging sensor according to a modification.
  • FIG. 20(a) is a diagram showing a schematic configuration of a different-axis ranging sensor according to a modification.
  • FIG. 20(b) is a diagram showing a schematic configuration of a different-axis ranging sensor according to a modification.
  • FIG. 20(c) is a diagram showing a schematic configuration of another axis ranging sensor according to a modification.
  • FIG. 21 is a perspective view showing a laser processing device according to a modification.
  • FIG. 22(a) is a side view showing an object without the transparent tape.
  • FIG. 22(b) is a side view showing an object provided with a transparent tape.
  • FIG. 23 is a side view of the object for explaining calculation of the offset amount.
  • FIG. 24 is a flowchart illustrating an example of height setting.
  • the laser processing apparatus 200 forms a modified region in the object 1 by irradiating the object 1 with laser light.
  • a plate-like member for example, a substrate, a wafer, etc.
  • the target object 1 is provided with cutting lines 5 for cutting the target object 1 .
  • the planned cutting line 5 is a straight imaginary line.
  • the line to cut 5 is not limited to a straight line, it may be curved, it may be a three-dimensional combination of these, or it may be coordinate-designated.
  • the line to cut 5 is not limited to a virtual line, and may be a line actually drawn on the surface of the object 1 .
  • the modified region may be formed continuously or intermittently.
  • the modified region may be linear or dotted, and the point is that the modified region should be formed at least inside the object 1 .
  • a crack may be formed starting from the modified region, and the crack and the modified region may be exposed on the outer surface (front surface, back surface, or outer peripheral surface) of the object 1 .
  • the laser light incident surface for forming the modified region is not limited to the front surface of the object 1 and may be the rear surface of the object 1 .
  • a modified region is a region whose density, refractive index, mechanical strength, and other physical properties are different from those of its surroundings.
  • the modified region includes, for example, a melt treated region (meaning at least one of a region once melted and resolidified, a region in a molten state, and a region in a state of being melted and resolidified), a crack region, There are a dielectric breakdown region, a refractive index change region, and the like, and there is also a region where these are mixed.
  • the modified region includes a region in which the density of the modified region is changed compared to the density of the non-modified region in the material of the object 1, and a region in which lattice defects are formed. When the material of the object 1 is single crystal silicon, the modified region can also be said to be a high dislocation density region.
  • the melt-processed region, the refractive index changing region, the region where the density of the modified region is changed compared to the density of the non-modified region, and the region where lattice defects are formed are further divided into the inside of these regions and the modified region.
  • Cracks may be included at the interface between the and the unmodified region. The included cracks may extend over the entire surface of the modified region, or may be formed only in a portion or in multiple portions.
  • Object 1 comprises a substrate made of a crystalline material having a crystalline structure.
  • the object 1 includes a substrate made of at least one of gallium nitride (GaN), silicon (Si), silicon carbide (SiC), LiTaO 3 and sapphire (Al 2 O 3 ).
  • the object 1 comprises, for example, a gallium nitride substrate, a silicon substrate, a SiC substrate, a LiTaO3 substrate, or a sapphire substrate.
  • the crystalline material may be either an anisotropic crystal or an isotropic crystal.
  • the object 1 may include a substrate made of an amorphous material having an amorphous structure (amorphous structure), such as a glass substrate.
  • a modified region can be formed by forming a plurality of modified spots (processing marks) along the line 5 to cut.
  • a plurality of modified spots gather to form a modified region.
  • a modified spot is a modified portion formed by one pulse shot of pulsed laser light (that is, one pulse of laser irradiation: laser shot).
  • Modified spots include crack spots, melted spots, refractive index change spots, or a mixture of at least one of these.
  • the size and the length of the crack that occurs are appropriately controlled in consideration of the required cutting accuracy, the required flatness of the cut surface, the thickness, type, crystal orientation, etc. of the object 1. can do.
  • modified spots can be formed as modified regions along the line to cut 5 .
  • the laser processing apparatus 200 includes an apparatus frame 210, a first moving mechanism 220, a support base (supporting portion) 230, and a second moving mechanism (moving mechanism) 240. . Furthermore, the laser processing apparatus 200 includes a laser output section 300 , a laser condensing section (irradiation section) 400 and a control section 500 .
  • the first moving mechanism 220 is attached to the device frame 210 .
  • the first moving mechanism 220 has a first rail unit 221 , a second rail unit 222 and a movable base 223 .
  • the first rail unit 221 is attached to the device frame 210 .
  • the first rail unit 221 is provided with a pair of rails 221a and 221b extending along the Y-axis direction.
  • the second rail unit 222 is attached to a pair of rails 221a and 221b of the first rail unit 221 so as to be movable along the Y-axis direction.
  • the second rail unit 222 is provided with a pair of rails 222a and 222b extending along the X-axis direction.
  • the movable base 223 is attached to a pair of rails 222a and 222b of the second rail unit 222 so as to be movable along the X-axis direction.
  • the movable base 223 is rotatable about an axis parallel to the Z-axis direction.
  • the support base 230 is attached to the movable base 223.
  • the support base 230 supports the object 1 .
  • the object 1 is formed as a plurality of functional elements (light receiving elements such as photodiodes, light emitting elements such as laser diodes, or circuits formed on the surface side of a substrate made of a semiconductor material such as silicon, for example). circuit elements, etc.) are formed in a matrix.
  • the surface 1 a (the surface facing the plurality of functional elements) of the object 1 is attached onto the film 12 stretched over the annular frame 11 .
  • the support base 230 supports the object 1 by holding the frame 11 with a clamp and sucking the film 12 with a vacuum chuck table.
  • the object 1 On the support base 230, the object 1 has a plurality of parallel lines to cut 5a and a plurality of parallel lines to cut 5b between adjacent functional elements (hereinafter also referred to as "street"). It is set in a grid pattern so that it can pass through.
  • the support base 230 is moved along the Y-axis direction by operating the second rail unit 222 in the first moving mechanism 220 . Further, the support table 230 is moved along the X-axis direction by operating the movable base 223 in the first moving mechanism 220 . Further, the support table 230 is rotated about an axis parallel to the Z-axis direction by the operation of the movable base 223 in the first moving mechanism 220 .
  • the support base 230 is attached to the device frame 210 so as to be movable along the X-axis direction and the Y-axis direction and to be rotatable about an axis line parallel to the Z-axis direction.
  • the laser output unit 300 is attached to the device frame 210 .
  • the laser focusing section 400 is attached to the device frame 210 via the second moving mechanism 240 .
  • the laser condensing section 400 is moved along the Z-axis direction (the optical axis direction of the condensing lens unit 430 to be described later) by operating the second moving mechanism 240 . In this manner, the laser condensing section 400 is attached to the device frame 210 so as to be movable along the Z-axis direction with respect to the laser output section 300 .
  • the control unit 500 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.
  • the control section 500 controls the operation of each section of the laser processing apparatus 200 . Details of the processing by the control unit 500 will be described later.
  • modified regions are formed inside the object 1 along the lines to cut 5a and 5b as follows.
  • the object 1 is supported on the support base 230 so that the back surface 1b of the object 1 becomes the laser beam incident surface, and each planned cutting line 5a of the object 1 is aligned in a direction parallel to the X-axis direction.
  • Alignment is performed to align the position of the condenser lens unit 430 (to be described later) in the Z-axis direction with respect to the laser light incident surface to the reference position.
  • the second moving mechanism 240 moves the laser focusing unit 400 in the Z-axis direction so that the focal point of the laser beam L is located at a position separated from the laser beam incident surface by a predetermined distance inside the object 1. . While the distance between the laser light incident surface and the focal point of the laser light L is maintained constant, the focal point of the laser light L is relatively moved along each line to cut 5a. Thereby, a modified region is formed inside the object 1 along each line to cut 5a.
  • the laser light incident surface is not limited to the back surface 1b, and may be the front surface 1a.
  • each planned cutting line 5b of the object 1 is moved in a direction parallel to the X-axis direction. be matched. Height set is performed.
  • the laser focusing unit 400 is moved by the second moving mechanism 240 so that the focal point of the laser beam L is located at a position separated from the laser beam incident surface by a predetermined distance inside the object 1 . While the distance between the laser light incident surface and the converging point of the laser light L is maintained constant, the converging point of the laser light L is relatively moved along each line to cut 5b. Thereby, a modified region is formed inside the object 1 along each line to cut 5b.
  • the direction parallel to the X-axis direction is the processing direction (the scanning direction of the laser beam L).
  • the relative movement of the focal point of the laser light L along each line to cut 5a and the relative movement of the focal point of the laser light L along each line to cut 5b are performed by the first moving mechanism This is done by moving the support base 230 along the X-axis direction by means of 220 .
  • the relative movement of the focal point of the laser light L between the lines to cut 5a and the relative movement of the focal point of the laser light L between the lines to cut 5b are performed by the first moving mechanism 220. It is implemented by moving the support base 230 along the Y-axis direction.
  • the laser output section 300 has a mounting base 301, a cover 302, and a plurality of mirrors 303,304. Furthermore, the laser output unit 300 includes a laser oscillator (laser light source) 310, a shutter 320, a ⁇ /2 wavelength plate unit (output adjustment unit, polarization direction adjustment unit) 330, and a polarizing plate unit (output adjustment unit, polarization direction adjustment unit). adjustment section) 340 , a beam expander (laser beam parallelization section) 350 , and a mirror unit 360 .
  • a mounting base 301 supports a plurality of mirrors 303 and 304, a laser oscillator 310, a shutter 320, a ⁇ /2 wavelength plate unit 330, a polarizing plate unit 340, a beam expander 350 and a mirror unit 360.
  • a plurality of mirrors 303 and 304 , laser oscillator 310 , shutter 320 , ⁇ /2 wavelength plate unit 330 , polarizing plate unit 340 , beam expander 350 and mirror unit 360 are attached to main surface 301 a of attachment base 301 .
  • the mounting base 301 is a plate-like member, and is detachable from the apparatus frame 210 (see FIG. 1).
  • the laser output unit 300 is attached to the device frame 210 via an attachment base 301 . In other words, the laser output section 300 is detachable with respect to the device frame 210 .
  • the cover 302 covers a plurality of mirrors 303 and 304, a laser oscillator 310, a shutter 320, a ⁇ /2 wavelength plate unit 330, a polarizing plate unit 340, a beam expander 350 and a mirror unit 360 on the main surface 301a of the mounting base 301. covering.
  • the cover 302 is detachable with respect to the mounting base 301 .
  • the laser oscillator 310 pulse-oscillates linearly polarized laser light L along the X-axis direction.
  • the wavelength of the laser light L emitted from the laser oscillator 310 is included in one of the wavelength bands of 500-550 nm, 1000-1150 nm, or 1300-1400 nm.
  • a laser beam L in a wavelength band of 500 to 550 nm is suitable for internal absorption laser processing of a substrate made of sapphire, for example.
  • Laser light L in wavelength bands of 1000 to 1150 nm and 1300 to 1400 nm is suitable for internal absorption laser processing of a substrate made of silicon, for example.
  • the polarization direction of the laser light L emitted from the laser oscillator 310 is parallel to the Y-axis direction, for example.
  • a laser beam L emitted from the laser oscillator 310 is reflected by the mirror 303 and enters the shutter 320 along the Y-axis direction.
  • ON/OFF of the output of the laser light L is switched as follows.
  • ON/OFF switching of a Q switch AOM (acousto-optic modulator), EOM (electro-optic modulator), etc.
  • AOM acousto-optic modulator
  • EOM electro-optic modulator
  • the laser oscillator 310 is composed of a fiber laser
  • the output of the laser light L can be turned on and off at high speed by switching the output of the semiconductor laser that constitutes the seed laser and the amplifier (excitation) laser.
  • ON/OFF of the output of the laser light L can be turned on/off at high speed by switching ON/OFF of the external modulation element (AOM, EOM, etc.) provided outside the resonator. can be switched to
  • the shutter 320 opens and closes the optical path of the laser light L by a mechanical mechanism. ON/OFF switching of the output of the laser light L from the laser output unit 300 is performed by switching ON/OFF of the output of the laser light L in the laser oscillator 310 as described above. As a result, the laser light L is prevented from being emitted unexpectedly from the laser output unit 300, for example.
  • the laser light L that has passed through the shutter 320 is reflected by the mirror 304 and sequentially enters the ⁇ /2 wavelength plate unit 330 and the polarizing plate unit 340 along the X-axis direction.
  • the ⁇ /2 wavelength plate unit 330 and the polarizing plate unit 340 function as an output adjustment section that adjusts the output (light intensity) of the laser light L. Also, the ⁇ /2 wavelength plate unit 330 and the polarizing plate unit 340 function as a polarization direction adjusting section that adjusts the polarization direction of the laser light L. FIG. Details of these will be described later.
  • the laser light L that has sequentially passed through the ⁇ /2 wavelength plate unit 330 and the polarizing plate unit 340 is incident on the beam expander 350 along the X-axis direction.
  • the beam expander 350 parallelizes the laser light L while adjusting the diameter of the laser light L.
  • the laser light L that has passed through the beam expander 350 is incident on the mirror unit 360 along the X-axis direction.
  • the mirror unit 360 has a support base 361 and a plurality of mirrors 362 and 363.
  • a support base 361 supports a plurality of mirrors 362 and 363 .
  • the support base 361 is attached to the attachment base 301 so as to be positionally adjustable along the X-axis direction and the Y-axis direction.
  • the mirror 362 reflects the laser light L that has passed through the beam expander 350 in the Y-axis direction.
  • the mirror 362 is attached to the support base 361 so that its reflecting surface can be angularly adjusted around an axis parallel to the Z-axis.
  • the mirror 363 reflects the laser light L reflected by the mirror 362 in the Z-axis direction.
  • the mirror 363 is attached to the support base 361 so that its reflective surface is angularly adjustable around an axis parallel to the X-axis and positionally adjustable along the Y-axis.
  • the laser beam L reflected by the mirror 363 passes through an opening 361a formed in the support base 361 and enters the laser beam concentrator 400 (see FIG. 1) along the Z-axis direction.
  • the direction in which the laser beam L is emitted by the laser output section 300 matches the moving direction of the laser condensing section 400 .
  • each mirror 362, 363 has a mechanism for adjusting the angle of the reflecting surface.
  • the position adjustment of the support base 361 with respect to the mounting base 301, the position adjustment of the mirror 363 with respect to the support base 361, and the angle adjustment of the reflecting surfaces of the mirrors 362 and 363 are performed.
  • the position and angle of the optical axis of the emitted laser light L are aligned with the laser condensing section 400 .
  • the multiple mirrors 362 and 363 are configured to adjust the optical axis of the laser light L emitted from the laser output section 300 .
  • the laser focusing unit 400 has a housing 401.
  • the housing 401 has a rectangular parallelepiped shape whose longitudinal direction is the Y-axis direction.
  • a second moving mechanism 240 is attached to one side surface 401e of the housing 401 (see FIGS. 5 and 7).
  • the housing 401 is provided with a cylindrical light entrance portion 401a so as to face the opening 361a of the mirror unit 360 in the Z-axis direction.
  • the light incident portion 401 a causes the laser light L emitted from the laser output portion 300 to enter the housing 401 .
  • the mirror unit 360 and the light incident part 401a are separated from each other by a distance that prevents them from coming into contact with each other when the second moving mechanism 240 moves the laser focusing part 400 along the Z-axis direction.
  • the laser focusing unit 400 has a mirror 402 and a dichroic mirror 403. Furthermore, the laser condensing unit 400 includes a reflective spatial light modulator (spatial light modulator) 410, a 4f lens unit 420, a condensing lens unit 430, a drive mechanism 440, and a pair of separate axis distance measuring sensors ( and a displacement information acquisition unit) 450 .
  • the laser condensing unit 400 irradiates the object 1 with laser light L through the condensing lens unit 430 .
  • the mirror 402 is attached to the bottom surface 401b of the housing 401 so as to face the light entrance section 401a in the Z-axis direction.
  • the mirror 402 reflects the laser beam L that has entered the housing 401 through the light entrance portion 401a in a direction parallel to the XY plane.
  • a laser beam L collimated by the beam expander 350 of the laser output unit 300 is incident on the mirror 402 along the Z-axis direction. That is, the laser light L is incident on the mirror 402 along the Z-axis direction as parallel light. Therefore, even if the second moving mechanism 240 moves the laser focusing unit 400 along the Z-axis direction, the state of the laser beam L incident on the mirror 402 along the Z-axis direction is kept constant.
  • Laser light L reflected by mirror 402 enters reflective spatial light modulator 410 .
  • the reflective spatial light modulator 410 is attached to the end 401c of the housing 401 in the Y-axis direction with the reflecting surface 410a facing the inside of the housing 401.
  • the reflective spatial light modulator 410 is, for example, a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) spatial light modulator (SLM: Spatial Light Modulator). directionally reflected.
  • LCOS Liquid Crystal on Silicon
  • SLM Spatial Light Modulator
  • the laser light L modulated and reflected by the reflective spatial light modulator 410 enters the 4f lens unit 420 along the Y-axis direction.
  • the optical axis of the laser light L incident on the reflective spatial light modulator 410 and the optical axis of the laser light L emitted from the reflective spatial light modulator 410 are formed.
  • the angle ⁇ is an acute angle (eg, 10-60°). That is, the laser light L is reflected at an acute angle along the XY plane by the reflective spatial light modulator 410 . This is because the incident angle and the reflection angle of the laser light L are suppressed to suppress the deterioration of the diffraction efficiency, and the performance of the reflective spatial light modulator 410 can be exhibited sufficiently.
  • the 4f lens unit 420 has a holder 421 , a lens 422 on the reflective spatial light modulator 410 side, a lens 423 on the condenser lens unit 430 side, and a slit member 424 .
  • a holder 421 holds a pair of lenses 422 and 423 and a slit member 424 .
  • the holder 421 maintains a constant positional relationship between the pair of lenses 422 and 423 and the slit member 424 in the direction along the optical axis of the laser beam L. As shown in FIG.
  • a pair of lenses 422 and 423 constitute a double-telecentric optical system in which the reflecting surface 410a of the reflective spatial light modulator 410 and the entrance pupil surface 430a of the condenser lens unit 430 are in an imaging relationship.
  • the image of the laser light L on the reflecting surface 410 a of the reflective spatial light modulator 410 (the image of the laser light L modulated by the reflective spatial light modulator 410 ) is projected onto the entrance pupil plane of the condenser lens unit 430 . It is transferred (imaged) to 430a.
  • a slit 424 a is formed in the slit member 424 .
  • the slit 424 a is located between the lens 422 and the lens 423 and near the focal plane of the lens 422 .
  • An unnecessary portion of the laser light L modulated and reflected by the reflective spatial light modulator 410 is cut off by the slit member 424 .
  • the laser light L that has passed through the 4f lens unit 420 is incident on the dichroic mirror 403 along the Y-axis direction.
  • the dichroic mirror 403 reflects most of the laser light L (eg, 95 to 99.5%) in the Z-axis direction, and reflects a portion of the laser light L (eg, 0.5 to 5%) in the Y-axis direction. permeate along. Most of the laser light L is reflected perpendicularly along the ZX plane by the dichroic mirror 403 .
  • the laser light L reflected by the dichroic mirror 403 enters the condenser lens unit 430 along the Z-axis direction.
  • the condenser lens unit 430 is attached via a drive mechanism 440 to the end 401d (the end opposite to the end 401c) of the housing 401 in the Y-axis direction.
  • the condenser lens unit 430 has a holder 431 and a plurality of condenser lenses 432 .
  • a holder 431 holds a plurality of condenser lenses 432 .
  • a plurality of condensing lenses 432 converge the laser light L on the object 1 (see FIG. 1) supported by the support base 230 .
  • the driving mechanism 440 moves the condenser lens unit 430 along the Z-axis direction by the driving force of the piezoelectric element.
  • the separate-axis distance measuring sensors 450 are attached to the ends 401d of the housing 401 so as to be positioned on both sides of the condenser lens unit 430 in the X-axis direction.
  • the separate-axis ranging sensor 450 uses the first measurement laser beam to obtain displacement information that changes according to the displacement of the laser beam incident surface of the object 1 (see FIG. 1).
  • the separate-axis distance measuring sensor 450 emits a first measurement laser beam (measurement laser beam) to the laser beam incident surface of the object 1 (see FIG. 1) supported by the support base 230, and the laser beam By receiving the first measurement laser beam reflected by the incident surface, the displacement information of the laser beam incident surface of the object 1 is acquired.
  • sensors such as a triangulation distance measurement method, a laser confocal method, a white light confocal method, a spectral interference method, an astigmatism method, or the like can be used.
  • the laser focusing unit 400 has a beam splitter 461, a pair of lenses 462 and 463, and a camera 464 for monitoring the intensity distribution of the laser light L.
  • the beam splitter 461 splits the laser light L transmitted through the dichroic mirror 403 into a reflected component and a transmitted component.
  • the laser light L reflected by the beam splitter 461 is sequentially incident on a pair of lenses 462 and 463 and a camera 464 along the Z-axis direction.
  • a pair of lenses 462 and 463 constitute a double-telecentric optical system in which the entrance pupil plane 430a of the condenser lens unit 430 and the imaging plane of the camera 464 are in an imaging relationship.
  • the image of the laser light L on the entrance pupil plane 430 a of the condenser lens unit 430 is transferred (imaged) onto the imaging plane of the camera 464 .
  • the image of the laser light L on the entrance pupil plane 430 a of the condenser lens unit 430 is the image of the laser light L modulated by the reflective spatial light modulator 410 . Therefore, in the laser processing apparatus 200, the operation state of the reflective spatial light modulator 410 can be grasped by monitoring the imaging result by the camera 464.
  • the laser focusing unit 400 has a beam splitter 471, a lens 472, and a camera 473 for monitoring the optical axis position of the laser light L.
  • the beam splitter 471 splits the laser light L transmitted through the beam splitter 461 into a reflected component and a transmitted component.
  • the laser light L reflected by the beam splitter 471 is sequentially incident on the lens 472 and the camera 473 along the Z-axis direction.
  • the lens 472 converges the incident laser light L on the imaging surface of the camera 473 .
  • a plurality of beam splitters 461 and 471 are arranged in a cylindrical body 404 extending from the end 401d of the housing 401 along the Y-axis direction.
  • a pair of lenses 462 and 463 are arranged in a cylindrical body 405 standing on the cylindrical body 404 along the Z-axis direction, and a camera 464 is arranged at the end of the cylindrical body 405 .
  • the lens 472 is arranged inside a cylindrical body 406 erected on the cylindrical body 404 along the Z-axis direction, and the camera 473 is arranged at the end of the cylindrical body 406 .
  • the cylindrical body 405 and the cylindrical body 406 are arranged side by side in the Y-axis direction.
  • the laser light L transmitted through the beam splitter 471 may be absorbed by a damper or the like provided at the end of the cylindrical body 404, or may be used for appropriate purposes. .
  • the laser focusing unit 400 includes a visible light source 481, a plurality of lenses 482, a reticle 483, a mirror 484, a half mirror 485, a beam splitter 486, and a lens 487. , an observation camera (imaging unit) 488 and a coaxial ranging sensor 460 .
  • the visible light source 481 emits visible light V along the Z-axis direction.
  • a plurality of lenses 482 collimate the visible light V emitted from the visible light source 481 .
  • a reticle 483 marks the visible light V.
  • the mirror 484 reflects the visible light V collimated by the multiple lenses 482 in the X-axis direction.
  • Half mirror 485 splits visible light V reflected by mirror 484 into a reflected component and a transmitted component.
  • the visible light V reflected by the half mirror 485 is sequentially transmitted through the beam splitter 486 and the dichroic mirror 403 along the Z-axis direction, passes through the condenser lens unit 430, and reaches the object 1 ( (See FIG. 1).
  • the visible light V irradiated to the object 1 is reflected by the laser beam incident surface of the object 1, enters the dichroic mirror 403 via the condenser lens unit 430, and passes through the dichroic mirror 403 along the Z-axis direction. do.
  • the beam splitter 486 splits the visible light V transmitted through the dichroic mirror 403 into a reflected component and a transmitted component.
  • the beam splitter 486 also reflects a second measurement laser beam L2 and its reflected light L2R, which will be described later.
  • the visible light V that has passed through the beam splitter 486 passes through the half mirror 485 and sequentially enters the lens 487 and observation camera 488 along the Z-axis direction.
  • the lens 487 converges the incident visible light V onto the imaging surface of the observation camera 488 .
  • Observation camera 488 captures an image of the laser beam incident surface of object 1 .
  • the observation camera 488 receives the visible light V which is incident on the laser light incident surface via the reticle 483 and reflected by the laser light incident surface.
  • the state of the object 1 can be grasped by observing the imaging result by the observation camera 488.
  • a mirror 484 , a half mirror 485 and a beam splitter 486 are arranged in a holder 407 attached on the end 401 d of the housing 401 .
  • a plurality of lenses 482 and reticles 483 are arranged in a cylindrical body 408 erected on the holder 407 along the Z-axis direction, and a visible light source 481 is arranged at the end of the cylindrical body 408 .
  • the lens 487 is arranged inside a cylindrical body 409 erected on the holder 407 along the Z-axis direction, and the observation camera 488 is arranged at the end of the cylindrical body 409 .
  • the cylindrical body 408 and the cylindrical body 409 are arranged side by side in the X-axis direction.
  • the visible light V transmitted through the half mirror 485 along the X-axis direction and the visible light V reflected in the X-axis direction by the beam splitter 486 are each absorbed by a damper or the like provided on the wall of the holder 407. Alternatively, it may be used for an appropriate purpose.
  • a coaxial ranging sensor 460 is attached to the side surface of the holder 407 .
  • the coaxial distance measuring sensor 460 emits the second measurement laser beam L2 toward the laser beam incident surface of the object 1 (see FIG. 1) supported by the support table 230, and the second measurement laser beam L2 is reflected by the laser beam incident surface.
  • the displacement information of the laser light incident surface of the object 1 is acquired.
  • the second measurement laser beam L2 emitted from the coaxial distance measuring sensor 460 is reflected by the beam splitter 486, transmitted through the dichroic mirror 403, guided to the condenser lens unit 430, and near the focal point of the condenser lens unit 430. and is reflected by the laser beam incident surface.
  • the reflected light L2R returns to the coaxial ranging sensor 460 through a path opposite to that of the second measurement laser light L2.
  • the coaxial ranging sensor 460 acquires displacement information of the object 1 by utilizing the fact that the state of the reflected light L2R changes depending on the position of the laser light incident surface with respect to the condenser lens unit 430 .
  • an astigmatic sensor or the like can be used as the coaxial ranging sensor 460.
  • the separate-axis distance measuring sensor 450 includes a light-emitting element 451 such as a laser diode that emits a first measurement laser beam L1, and a first measurement laser beam reflected by the laser beam incident surface of the object 1. and a linear photodiode array (light receiving element array) 453 that receives the laser light L1.
  • the first measurement laser beam L1 is emitted from the light emitting element 451 along a direction inclined with respect to the Z-axis direction.
  • the emitted first measurement laser beam L1 is condensed toward the object 1 via the lens 452 and reflected by the laser beam incident surface.
  • the reflected first measurement laser beam L1 travels along a direction that is inclined with respect to the Z-axis direction, is condensed toward the linear photodiode array 453 via the lens 454, and becomes a spot on the linear photodiode array 453.
  • Light is received at the position.
  • a spot position (hereinafter also simply referred to as "spot position"), which is the position of the light reception in the linear photodiode array 453, has a unique relationship with respect to the displacement of the laser light incident surface.
  • spot position hereinafter also simply referred to as "spot position”
  • the different-axis ranging sensor 450 acquires information corresponding to the spot position (light receiving position) as the displacement information.
  • a plurality of linear photodiode arrays 453 may be provided.
  • the control unit 500 determines whether the position in the Z-axis direction of the condenser lens unit 430 (condensing lens 432) with respect to the laser beam incident surface is a reference position or a predetermined distance away from the reference position.
  • a first alignment process is executed to operate the second moving mechanism 240 so as to match the height position (that is, perform height setting).
  • the reference position is the position of the condenser lens unit 430 in the Z-axis direction when the mark of the reticle 483 is in focus on the image of the laser light incident surface captured by the observation camera 488 (hereinafter also referred to as "reticle focus position"). (see FIG. 9).
  • the optical system is adjusted so that the mark of the reticle 483 is focused on the laser beam incident surface. That is, the reticle focus position is the position when the mark of the reticle 483 is focused on the laser beam incident surface. In other words, the reticle focus position is the position of the condenser lens unit 430 in the Z-axis direction when the focal point of the condenser lens unit 430 is aligned with the laser incident surface. If the optical system is adjusted so that the mark on the reticle 483 is focused not on the laser light incident surface but at a predetermined height away from the laser light incident surface, the mark on the reticle 483 may be focused. The position at which the focus is achieved is not the laser beam incident surface, but a predetermined height position away from the laser beam incident surface by a predetermined distance.
  • the control unit 500 aligns the position of the condenser lens unit 430 in the Z-axis direction with the reference position or the predetermined height position by the first alignment process, and adjusts the spot position acquired by the separate-axis distance measuring sensor 450 to An information recording process is executed to record in the storage unit of the control unit 500 as a reference spot position (reference displacement information).
  • the control unit 500 operates the second moving mechanism 240 so that the spot position acquired by the different-axis distance measuring sensor 450 becomes the reference spot position, and the position of the condenser lens unit 430 in the Z-axis direction with respect to the laser beam incident surface. to a reference position or a predetermined height position (that is, perform height setting).
  • control unit 500 cannot recognize the focused state of the mark of the reticle 483 on the image of the laser light incident surface captured by the observation camera 488 as a result of executing the first alignment process, the reference spot position is recorded.
  • processing is executed to determine that the object 1 cannot be processed.
  • the control unit 500 cannot recognize the state in which the mark of the reticle 483 is in focus on the image of the laser light incident surface captured by the observation camera 488, the reference displacement information is recorded.
  • a switching process is executed to cause a second alignment process to be executed when recording is being performed by the unit.
  • the control unit 500 executes light receiving amount adjustment processing for adjusting the different-axis ranging sensor 450 so that the light receiving amount in the linear photodiode array 453 is equal to or greater than the threshold.
  • the adjustment of the different-axis distance measuring sensor 450 includes, for example, adjustment to increase at least one of the gain and the exposure time, and adjustment to increase the output of the light emitting element 451 .
  • the control unit 500 includes a first alignment unit, an information recording unit, a second alignment unit, a processing impossibility determination unit, a switching unit, and a light receiving amount adjustment unit.
  • height setting processing when recording the reference spot position in the control unit 500 (that is, when the reference spot position is not recorded or when updating the reference spot position) will be described with reference to the flowchart of FIG. explain. Note that height setting in this case is performed at the time of initial adjustment, calibration, optical axis adjustment, and the like.
  • the object 1 is placed on the support base 230 .
  • the controller 500 Based on the image of the laser beam incident surface of the object 1 captured by the observation camera 488 (the image projected by the reticle 483), the controller 500 adjusts the height position of the condenser lens unit 430 to match the reticle focus position. to drive the second moving mechanism 240 to move the laser focusing unit 400 in the Z-axis direction (step S1).
  • step S1 an image is acquired by the observation camera 488 at each position of the condenser lens unit 430 in the Z-axis direction, and image processing is performed on each image to obtain a numerical value (score) as an index of the contrast of the reticle 483. is calculated, and the position in the Z-axis direction of the laser condensing unit 400 at which the numerical value of the contrast becomes maximum (peak) with respect to the displacement in the Z-axis direction is defined as the reticle focus position.
  • an image processing method using pattern matching, Laplacian differentiation, or the like may be used.
  • step S2 determines whether the contrast score peak of the reticle 483 is optimal (step S2). For example, in step S2, if the peak of the numerical value of the contrast has not been detected in step S1, the decision is NO, and if the peak has been detected, the decision is YES. If NO in step S2, it is determined that the focused state of the marks on the reticle 483 on the image captured by the observation camera 488 cannot be recognized, and it is determined that an error has occurred (step S3). The control unit 500 determines that the object 1 on the support table 230 cannot be processed, and ends the process (step S4).
  • the support table is arranged so that the first measurement laser beam L1 hits the position where the reticle 483 is projected in step S1 (for example, the center position in the width direction of the street) on the laser beam incidence surface. 230 is moved horizontally to move the object 1 horizontally (step S5).
  • step S5 when the position of the support table 230 in the X-axis direction in step S1 is [X0], the position directly below the separate-axis distance measuring sensor 450 and the condenser lens unit 430 (light on the laser beam incidence surface ) are apart from each other by ⁇ in the machining progress direction, in step S5, the support table 230 is moved in the X-axis direction so that the position of the support table 230 in the X-axis direction is [X0+ ⁇ ].
  • Such movement of the support base 230 is unnecessary when a sensor coaxial with the condenser lens unit 430 is used as the displacement information acquisition section.
  • the spot position detected by the linear photodiode array 453 of the separate-axis distance measuring sensor 450 is recorded in the control unit 500 as the reference spot position (step S6). (Step S7).
  • the object 1 is placed on the support base 230 .
  • the controller 500 operates the second moving mechanism 240 to move the condenser lens unit 430 to the reticle focus position in the Z-axis direction so that the spot position detected by the linear photodiode array 453 becomes the reference spot position (step S11).
  • step S12 determines whether the light amount of the first measurement laser light received by the linear photodiode array 453 is optimal.
  • step S12 if the amount of light received by the linear photodiode array 453 is equal to or greater than the threshold, the determination is YES, and if the amount of light received by the linear photodiode array 453 is less than the threshold, the determination is NO. If NO in step S12, various parameters of the different-axis distance measuring sensor 450 are adjusted by the control unit 500, and then the process returns to step S11 (step S13).
  • step S12 the second moving mechanism 240 is operated by the control section 500 to move the position of the condenser lens unit 430 in the Z-axis direction to a predetermined height position (step S14).
  • the predetermined height position is an arbitrary height position corresponding to the depth of the modified region formed in the object 1 . Height setting is thus completed, and the process ends (step S15).
  • the position shown in FIG. 12(b) is detected as follows.
  • the second moving mechanism 240 moves the laser focusing unit 400 upward so that the spot position SP1 becomes the reference spot position SP0.
  • the condenser lens unit 430 is positioned at the height position corresponding to the reticle focus position, and the height setting is completed.
  • the laser processing apparatus 200 performs height setting based on the imaging result of the observation camera 488 .
  • the spot position acquired by the different-axis distance measuring sensor 450 at this time is recorded as the reference spot position.
  • the mark of the reticle 483 can be seen on the image of the laser light incident surface captured by the observation camera 488. may not be (see FIG. 13). In this case, from the image pickup result of the observation camera 488, it may become difficult to identify on the laser light incident surface, and height setting may become difficult.
  • height setting can be performed by operating the second moving mechanism 240 using the reference spot position. That is, the laser processing apparatus 200 has both functions of height setting based on the imaging result of the observation camera 488 and height setting based on the detection result of the separate axis distance measuring sensor 450. It is possible to set the height to
  • the laser processing apparatus 200 associates the spot position of the linear photodiode array 453 with the reticle focus position. Even if the thickness of the object 1 is varied, the relationship between the spot position and the reticle focus position remains unchanged. It is possible to perform height setting by using it. In the laser processing apparatus 200 , using the height set based on the imaging result of the observation camera 488 , a height set data set based on the detection result of the separate-axis ranging sensor 450 can be prepared. Note that the laser processing apparatus 200 is of course effective even when it is easy to identify on the laser beam incident surface.
  • the observation camera 488 receives the visible light V that is incident on the laser light incident surface via the reticle 483 and reflected by the laser light incident surface.
  • the reference position is the reticle focus position. In this case, height setting can be performed using the reticle 483 .
  • the relevant spot position is not recorded. It is determined that the object 1 cannot be processed. Accordingly, it can be determined that the object 1 cannot be processed because height setting cannot be performed.
  • the separate axis distance measuring sensor 450 includes a light emitting element 451 that emits the first measurement laser beam L1 and a linear photodiode array that receives the first measurement laser beam L1 reflected by the laser beam incident surface. 453 and . Displacement information that changes according to the displacement of the laser light incident surface corresponds to the spot position of the linear photodiode array 453 . In this case, height setting can be performed using the spot position of the linear photodiode array 453 as displacement information.
  • the laser processing device 200 adjusts the different-axis ranging sensor 450 so that the amount of light received by the linear photodiode array 453 is greater than or equal to the threshold. In this case, it is possible to prevent the inability to acquire effective spot position information due to a small amount of light received by the linear photodiode array 453 .
  • the control unit 500 As a result of performing height setting based on the imaging result of the observation camera 488, if the state in which the reticle 483 is in focus on the image of the laser light incident surface imaged by the observation camera 488 cannot be recognized, the reference When the spot position is recorded by the control unit 500, there is a case where the height setting is switched to the height setting based on the detection result of the separate-axis distance measuring sensor 450 (moving to the above step S11). In this case, the height setting based on the imaging result of the observation camera 488 is preferentially executed, and if the height setting is not possible, it is possible to switch to the height setting based on the detection result of the separate axis ranging sensor 450 .
  • the height-set processing performed by the laser processing apparatus 200 is not limited to the examples shown in FIGS.
  • the height set may be implemented as follows. Another processing example of height setting when recording the reference spot position in the control unit 500 will be described with reference to the flowchart of FIG.
  • the control unit 500 drives the second moving mechanism 240 so that the height position of the condenser lens unit 430 matches the reticle focus position. to move the laser focusing unit 400 in the Z-axis direction (step S21).
  • step S22 determines whether the contrast score peak of the reticle is optimal. If NO in step S22, it is determined that the focused state of the mark on the reticle 483 on the image captured by the observation camera 488 cannot be recognized, and it is determined that an error has occurred (step S23). As a result, the control unit 500 determines that the object 1 on the support table 230 cannot be processed, and the process is terminated (step S24). On the other hand, if YES in step S22, the controller 500 operates the second moving mechanism 240 to move the condenser lens unit 430 to a predetermined height in the Z-axis direction (step S25).
  • the predetermined height position is an arbitrary height position corresponding to the depth of the modified region formed in the object 1 .
  • the support table 230 is horizontally moved so that the first measurement laser beam L1 hits the position where the reticle 483 is projected in step S21 on the laser beam incidence surface, and the object is scanned. 1 is moved horizontally (step S26).
  • the spot position detected by the linear photodiode array 453 of the different-axis distance measuring sensor 450 is recorded in the controller 500 as a reference spot position (step S27). Height setting is thus completed, and the process ends (step S28).
  • the object 1 is placed on the support base 230 .
  • the second moving mechanism 240 is operated by the control unit 500 so that the spot position detected by the linear photodiode array 453 of the different-axis distance measuring sensor 450 becomes the reference spot position, and the condenser lens unit 430 is moved in the Z-axis direction. Move to a predetermined height position (step S31)
  • step S32 determines whether the light amount of the first measurement laser light L1 received by the linear photodiode array 453 is optimal (step S32). If NO in step S32, various parameters of the different-axis distance measuring sensor 450 are adjusted by the control unit 500, and then the process returns to step S31 (step S33). On the other hand, if the determination in step S32 is YES, the height setting is completed and the process ends (step S34).
  • the displacement information acquisition section is not particularly limited.
  • the displacement information acquisition unit may be a sensor using astigmatism, and in this case has a four-part split photodiode.
  • the above-described coaxial ranging sensor 460 may be used as the displacement information acquisition unit.
  • the displacement information acquisition unit may be a sensor using triangulation, in which case it has a linear photodiode array or a linear image sensor.
  • the displacement information acquisition unit may be a sensor using eccentric triangulation, in which case it has a linear photodiode array or a linear image sensor.
  • the displacement information acquisition unit may be a confocal sensor, in which case it has a photodiode.
  • the displacement information acquisition unit may be a sensor using spectral interference, and in this case has a CCD image sensor.
  • FIG. 16 is a schematic plan view showing a support base 230 and a reference support base (reference support portion) 230K of a laser processing apparatus 600 according to a modification.
  • FIG. 17 is a schematic plan view showing a state in which the target object 1 and the reference target object 1K are supported by the support base 230 and the reference support base 230K of FIG.
  • a laser processing apparatus 600 according to a modification may further include a reference support base 230K for the laser processing apparatus 200 described above.
  • the reference support base 230K supports the reference object 1K that does not include a film or tape material on the laser light incident surface side.
  • the reference support base 230K is arranged side by side with the support base 230 .
  • the reference support base 230K has a size corresponding to the size of the reference object 1K.
  • the reference support 230K is smaller than the support 230K.
  • the reference object 1K is an object that can be recognized when the mark of the reticle 483 is in focus on the image of the laser beam incident surface captured by the observation camera 488 .
  • the reference object 1K is an object for which YES is determined in step S2.
  • the controller 500 drives the first moving mechanism 220 and the second moving mechanism 240 to move the laser focusing part 400 so that the optical axis of the focusing lens unit 430 is positioned on the reference object 1K (step S41). ).
  • the second moving mechanism 240 is moved by the control unit 500 so that the height position of the condenser lens unit 430 matches the reticle focus position. It is driven to move the laser focusing unit 400 in the Z-axis direction (step S42).
  • the control unit 500 operates the second moving mechanism 240 to move the position of the condenser lens unit 430 in the Z-axis direction to a predetermined height position (step S43). Subsequently, in the same manner as in step S5, the laser beam condensing unit 400 is horizontally moved so that the first measurement laser beam L1 hits the position where the reticle 483 was projected in step S42 on the laser beam incident surface (step S44). Subsequently, the spot position detected by the linear photodiode array 453 of the different-axis distance measuring sensor 450 at that time is recorded in the controller 500 as a reference spot position (step S45). Height setting is thus completed, and the process ends (step S46).
  • the object 1 is placed on the support base 230 .
  • the second moving mechanism 240 is operated by the control unit 500 so that the spot position detected by the linear photodiode array 453 of the different-axis distance measuring sensor 450 becomes the reference spot position, and the condenser lens unit 430 is moved in the Z-axis direction. It is moved to a predetermined height position (step S51).
  • the height setting is completed as described above, and the processing ends (step S52).
  • height setting is performed on the reference object 1K supported by the reference support base 230K based on the imaging result of the observation camera 488, and the spot position obtained at this time is referred to as the reference spot position.
  • the reference spot position can be recorded as Since the height setting is completed with the reference object 1K immediately before processing, it is resistant to optical axis deviation.
  • the control unit 500 controls the spot position acquired by the separate-axis ranging sensor 450 to be the reference spot position.
  • the second moving mechanism 240 is operated based on the imaging result of the observation camera 488 so that the position of the condenser lens unit 430 in the Z-axis direction with respect to the laser light incident surface matches the reference position. You may let
  • the laser focusing unit 400 is arbitrarily moved along the Z-axis direction so that the focal point of the focusing lens unit 430 is positioned at the center of the object 1 (step S61).
  • the controller 500 operates the second moving mechanism 240 so that the spot position detected by the linear photodiode array 453 of the different-axis distance measuring sensor 450 becomes the reference spot position, and the condenser lens unit moves in the Z-axis direction. 430 is moved (step S62).
  • the second moving mechanism 240 is operated so that the reticle focus position is retrieved, that is, the reference position is matched based on the imaging result of the observation camera 488 (step S63). This makes it possible to speed up the height setting as compared to the case of performing the height setting without using the spot position of the separate axis ranging sensor 450 (the case of performing the height setting only from the imaging result of the observation camera 488). .
  • a branching optical system 455 that branches the reflected first measurement laser beam L1 into a plurality of (here, two) branch measurement laser beams L11 and L12 may be included.
  • the linear photodiode array 453 receives two branch measurement laser beams L11 and L12.
  • the displacement information that changes according to the displacement of the laser beam incident surface corresponds to the intervals H1, H2, H3 between the light receiving positions of the two branch measurement laser beams L11, L12 in the linear photodiode array 453.
  • FIG. Branching optical system 455 includes lens 456 and lens 457 .
  • the intervals between the branch measurement laser beams L11 and L12 change to intervals H1, H2, and H3. Change.
  • height setting can be performed using the intervals H1, H2, and H3 between the light receiving positions of the laser beams L11 and L12 for branch measurement in the linear photodiode array 453 as displacement information.
  • the spatial light modulator is not limited to a reflective spatial light modulator, and may include a transmissive spatial light modulator.
  • the modified region may be, for example, a crystalline region, a recrystallized region, or a gettering region formed inside the object 1 .
  • a crystalline region is a region that maintains the structure of the object 1 before processing.
  • a recrystallized region is a region that is solidified as a single crystal or polycrystal when it is resolidified after being vaporized, plasmatized, or melted.
  • the gettering region is a region exhibiting a gettering effect of collecting and capturing impurities such as heavy metals, and may be formed continuously or intermittently.
  • the reference spot position is stored in the control unit 500 in the above embodiment, the storage mode is not particularly limited.
  • the reference spot positions to be recorded may be prepared as a data set based on the imaging result of the observation camera 488 and the detection result of the separate axis ranging sensor 450, as described above.
  • Such a data set for example, "represents each position (including the reticle focus position) in the Z-axis direction of the condenser lens unit 430 and the spot position of the linear photodiode array 453 corresponding to each position. coordinate table” may be included. In this case, height setting independent of the object 1 is possible. Further, height setting can be performed without requiring a process of detecting the position of the laser beam incident surface.
  • the transparent tape 101 is a tape-shaped transparent member that is transparent to the laser beam L and the first measurement laser beam L1.
  • the marks of the reticle 483 may blur on the image of the laser light incident surface captured by the observation camera 488, making height setting difficult.
  • the fact that the transparent tape 101 has transparency means that the transparency of the transparent tape 101 is higher than that of the part of the object 1 other than the transparent tape 101 .
  • Having transparency means, for example, that the laser beam L and the first measurement laser beam L1 are transmitted.
  • the laser beam L and the first measurement laser beam L1 pass while maintaining their intensity.
  • having transparency may mean that the transmittance for the laser beam L and the first measurement laser beam L1 is 85% or more.
  • the object 1 is a through silicon via (TSV) wafer with a thickness of 30 ⁇ m.
  • the control unit 500 of the laser processing apparatus 700 uses the tape information (transmissive member information).
  • the control unit 500 changes the pre-stored reference spot position based on the calculated offset amount.
  • the control unit 500 adjusts the reference spot position based on the offset amount so as to eliminate the displacement of the reference spot position caused by the change in the optical path of the first measurement laser beam L1 due to the presence of the transparent tape 101. to correct.
  • the tape information includes information regarding the thickness and refractive index of the transparent tape 101 .
  • the offset amount is the optical path of the first measuring laser beam L1B with the transparent tape 101 (see FIG. 22 (a)) with respect to the optical path of the first measuring laser beam L1A without the transparent tape 101 (see FIG. 22(a)). b) corresponds to the deviation of).
  • the reference spot position is obtained and stored in advance in the same manner as above.
  • the reference spot position is determined when the position of the condenser lens unit 430 in the Z-axis direction is aligned with the reference position or the predetermined height position by the first alignment process on the object 1 on which the transparent tape 101 is not provided. It is the spot position acquired by the axial ranging sensor 450 .
  • the laser processing apparatus 700 includes an input unit 701 that receives input regarding the presence or absence of the transparent tape 101 and tape information.
  • the input unit 701 for example, the presence or absence of the transparent tape 101 and the thickness and refractive index of the transparent tape 101 are input by selection by the user or the like.
  • the input unit 701 is not particularly limited, and various devices may be used.
  • the control unit 500 determines whether or not the transparent tape 101 is present based on the input regarding the presence or absence of the transparent tape 101 from the input unit 701 . If the control unit 500 determines that the transparent tape 101 is present, the control unit 500 calculates the offset amount based on the input regarding the tape information from the input unit 701 .
  • step S71 determines whether or not the transparent tape 101 is on the laser beam incident surface of the object 1 (step S71). If YES in step S71, the control unit 500 calculates the offset amount based on the tape information input by the input unit 701 (step S72). The control unit 500 changes the pre-stored reference spot position based on the calculated offset amount (step S74).
  • the second moving mechanism 240 is operated by the control unit 500 so that the spot position detected by the linear photodiode array 453 of the different-axis distance measuring sensor 450 becomes the reference spot position, and the condenser lens is moved in the Z-axis direction.
  • the unit 430 is moved to the reticle focus position (step S75).
  • the controller 500 determines whether the light amount of the first measurement laser light L1 received by the linear photodiode array 453 is optimal (step S76). If YES in step S76, the control unit 500 operates the second moving mechanism 240 to move the position of the condenser lens unit 430 in the Z-axis direction to a predetermined height position (step S77). If NO in step S76, various parameters of the different-axis distance measuring sensor 450 are adjusted by the control unit 500, and then the process returns to step S75 (step S78).
  • step S71 the control unit 500 operates the second moving mechanism 240 so that the spot position detected by the linear photodiode array 453 of the separate-axis distance measuring sensor 450 becomes the reference spot position.
  • the condenser lens unit 430 is moved to the reticle focus position in the Z-axis direction (step S79).
  • the controller 500 determines whether or not the light intensity of the first measurement laser light L1 received by the linear photodiode array 453 is optimal (step S80). If YES in step S80, the controller 500 operates the second moving mechanism 240 to move the condenser lens unit 430 to a predetermined height in the Z-axis direction (step S81).
  • step S80 various parameters of the different-axis distance measuring sensor 450 are adjusted by the control section 500, and then the process returns to step S79 (step S82). After step S77 or step S81, the height setting is completed and the process ends (step S83).
  • the laser processing apparatus 700 also exhibits the above effects. Further, in the laser processing apparatus 700, the separate axis distance measuring sensor 450 emits the first measurement laser beam L1 toward the laser beam incidence surface of the object 1, and the first measurement laser beam L1 reflected by the laser beam incidence surface By receiving the laser beam L1, the spot position (light receiving position, displacement information) in the linear photodiode array 453 is obtained.
  • the control unit 500 calculates the offset amount based on tape information including information about the thickness and refractive index of the transparent tape 101, and changes the pre-stored reference spot position based on the calculated offset amount. This makes it possible to deal with the object 1 having the transparent tape 101 on the laser beam incident surface. It is also possible to deal with the object 1 whose mark on the reticle 483 (see FIG. 7) is difficult to identify. It is possible to eliminate variations in the formation position of the modified region due to blurring of the marks of the reticle 483 .
  • the laser processing device 700 has an input section 701 .
  • the control unit 500 determines whether or not the transparent tape 101 is present based on the input from the input unit 701, and calculates the offset amount when it is determined that the transparent tape 101 is present. This makes it possible to use the input from the input unit 701 to deal with the object 1 having the transparent tape 101 on the laser beam incident surface. It is possible to switch (ON/OFF) the function of correcting the reference spot position based on the offset amount.
  • the transmissive member is not limited to the transparent tape 101, and may be other tape-shaped, film-shaped, layer-shaped, block-shaped, or other members.
  • the calculation for calculating the offset amount is not limited, and other calculations may be used.
  • the calculation for changing the reference spot position is not limited, and other calculations may be used.
  • the tape information may be input in advance via the input unit 701, or the refractive index and thickness of the transparent tape 101 may be measured for each laser processing.
  • each configuration in the above-described embodiments and modifications may be applied to processing such as trimming, slicing, and ablation.
  • Various materials and shapes can be applied to each configuration in the above-described embodiments and modifications without being limited to the materials and shapes described above.
  • each configuration in the above-described embodiment and modification can be arbitrarily applied to each configuration in another embodiment or modification.
  • Reference Signs List 1 Object 101 Transparent tape (transmissive member) 200, 600, 700 Laser processing device 230 Support base (support part) 230K Reference support base (reference support part) 240 Second Moving mechanism (moving mechanism) 400 Laser condensing unit (irradiating unit) 430 Condensing lens unit (condensing lens) 450 Different axis distance measuring sensor (displacement information acquiring unit) 451 Light emitting element 453 ... Linear photodiode array (light receiving element array), 483 ... Reticle, 488 ... Observation camera (imaging unit), 500 ... Control unit (first alignment unit, information recording unit, second alignment unit, unprocessable determination unit, 701 input unit L laser light L1, L1A, L1B first measurement laser light (measurement laser light).

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PCT/JP2022/009218 2021-06-01 2022-03-03 レーザ加工装置 WO2022254844A1 (ja)

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CN118089565A (zh) * 2024-04-23 2024-05-28 常州奥瑞克精密测量系统有限公司 一种具有多点式多姿态激光同轴度校验装置及方法

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JPH11201719A (ja) * 1998-01-09 1999-07-30 Nikon Corp 位置測定装置及びレーザ加工装置
JP2009034723A (ja) * 2007-08-03 2009-02-19 Hamamatsu Photonics Kk レーザ加工方法、レーザ加工装置及びその製造方法
JP2013096853A (ja) * 2011-11-01 2013-05-20 Omron Corp 変位センサ
JP2013132651A (ja) * 2011-12-26 2013-07-08 Hamamatsu Photonics Kk レーザ加工装置及びレーザ加工方法
JP2020157365A (ja) * 2019-03-28 2020-10-01 ブラザー工業株式会社 レーザマーカ

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JPH11201719A (ja) * 1998-01-09 1999-07-30 Nikon Corp 位置測定装置及びレーザ加工装置
JP2009034723A (ja) * 2007-08-03 2009-02-19 Hamamatsu Photonics Kk レーザ加工方法、レーザ加工装置及びその製造方法
JP2013096853A (ja) * 2011-11-01 2013-05-20 Omron Corp 変位センサ
JP2013132651A (ja) * 2011-12-26 2013-07-08 Hamamatsu Photonics Kk レーザ加工装置及びレーザ加工方法
JP2020157365A (ja) * 2019-03-28 2020-10-01 ブラザー工業株式会社 レーザマーカ

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