Laser processing device

Abstract

The laser processing apparatus of the present application has: a support portion; an irradiation portion that irradiates laser light on an object via a condensing lens; a moving mechanism that moves the condensing lens; an imaging portion that images a laser light incidence surface; a displacement information acquisition portion that acquires displacement information of the laser light incidence surface; a first alignment portion that operates the moving mechanism in such a manner that the position of the condensing lens is aligned with a reference position based on the imaging result obtained by the imaging portion; an information recording portion that records the displacement information acquired by the displacement information acquisition portion as reference displacement information when the position of the condensing lens is aligned with the reference position by the first alignment portion; and a second alignment portion that operates the moving mechanism in such a manner that the displacement information becomes the reference displacement information and aligns the position of the condensing lens with the reference position.

Description

Technical Field

[0001] This invention relates to a laser processing apparatus. Background Technology

[0002] Known laser processing apparatuses irradiate a workpiece with a laser to form a modified region (see, for example, Patent Document 1). Such a laser processing apparatus includes: a support section for supporting the workpiece, an irradiation section for irradiating the workpiece with a laser via a condenser lens, a moving mechanism for moving the condenser lens along the optical axis of the condenser lens, and an imaging section for photographing the laser incident surface of the workpiece.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-87053 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In the laser processing apparatus described above, there is a case where the following operation (i.e., height setting) is performed: a reticle is projected onto the laser-irradiated surface of the object, and a moving mechanism is activated by focusing the reticle on the image captured by the camera unit to align the position of the condenser lens relative to the optical axis of the laser incident surface with a reference position. However, in this case, for example, if a wafer with film or tape material on the laser incident surface is used as the object, there is a possibility that the reticle cannot be correctly identified on the image, and the condenser lens is difficult to align.

[0008] The purpose of this invention is to provide a laser processing apparatus that is not limited by the object being processed, and can align a focusing lens with the position along the optical axis of the laser incident surface.

[0009] Technical means for solving problems

[0010] One aspect of the laser processing apparatus of the present invention involves irradiating a workpiece with a laser to form a modified region. The laser processing apparatus includes: a support unit supporting the workpiece; an irradiation unit irradiating the workpiece with a laser via a condenser lens; a moving mechanism for moving the condenser lens along the optical axis of the condenser lens; an imaging unit for photographing the laser incident surface of the workpiece; a displacement information acquisition unit for acquiring displacement information corresponding to the displacement of the laser incident surface using a measuring laser; a first alignment unit for aligning the moving mechanism with the position of the condenser lens relative to the optical axis of the laser incident surface at a reference position or a predetermined height position away from the reference position based on the imaging results obtained by the imaging unit; an information recording unit for recording the displacement information acquired by the displacement information acquisition unit as reference displacement information when the position of the condenser lens relative to the optical axis of the laser incident surface is aligned with the reference position or the predetermined height position by the first alignment unit; and a second alignment unit for aligning the position of the condenser lens relative to the laser incident surface at the reference position or the predetermined height position by aligning the moving mechanism with the displacement information acquired by the displacement information acquisition unit as reference displacement information.

[0011] In this laser processing apparatus, the first alignment unit aligns the condenser lens with the position along the optical axis of the laser incident surface of the object based on the imaging results of the imaging unit (hereinafter, this alignment is also referred to as "height setting"). The displacement information acquired by the displacement information acquisition unit is then recorded as reference displacement information by the information recording unit. In cases where an object has a film or tape material on the laser incident surface, it may be difficult to identify the laser incident surface from the imaging results of the imaging unit, making height setting difficult. In such cases, one aspect of the present invention allows height setting by using the reference displacement information to actuate the moving mechanism via the second alignment unit. That is, in one aspect of the present invention, both height setting by the first alignment unit and height setting by the second alignment unit are provided, thereby enabling height setting regardless of the object being processed.

[0012] In one aspect of the laser processing apparatus of the present invention, the camera unit may receive visible light that has passed through the caliper and is incident on the laser incident surface and reflected by the laser incident surface. The reference position is the position of the condenser lens when the caliper is focused on the image of the laser incident surface captured by the camera unit. In this case, the height can be set using the caliper via the first alignment unit.

[0013] In one aspect of the laser processing apparatus of the present invention, an unprocessable determination unit may be included. This unit determines that an object is unprocessable when, during processing by the first alignment unit, the focus state of the caliper cannot be identified on the image of the laser incident surface captured by the camera unit, and the reference displacement information is not recorded by the information recording unit. Thus, since the height cannot be set, it can be determined that the object is unprocessable.

[0014] In one aspect of the laser processing apparatus of the present invention, a switching unit may be included, which, when the reference displacement information is recorded by the information recording unit in a situation where the focus state of the caliper cannot be identified on the image of the laser incident surface captured by the imaging unit during the processing performed by the first alignment unit, performs the processing performed by the second alignment unit. In this case, the height setting is preferentially performed by the first alignment unit, and if the height setting cannot be performed by the first alignment unit, the height setting can be switched to be performed by the second alignment unit.

[0015] In one aspect of the laser processing apparatus of the present invention, the displacement information acquisition unit may include: a light-emitting element that emits a measuring laser, and a light-receiving element array that receives the measuring laser reflected from the laser incident surface. The displacement information, which changes in response to the displacement of the laser incident surface, corresponds to the light-receiving position of the measuring laser in the light-receiving element array. In this case, the light-receiving position of the measuring laser in the light-receiving element array can be used as displacement information for height setting.

[0016] In one aspect of the laser processing apparatus of the present invention, the displacement information acquisition unit may include: a light-emitting element that emits a measuring laser, a branching optical system that branches the measuring laser reflected from the laser incident surface into multiple branch measuring lasers, and a light-receiving element array that receives the multiple branch measuring lasers. The displacement information, which changes in response to the displacement of the laser incident surface, is the interval between the light-receiving positions of the multiple branch measuring lasers in the light-receiving element array. In this case, the height can be set using the interval between the light-receiving positions of the branch measuring lasers in the light-receiving element array as displacement information.

[0017] One aspect of the laser processing apparatus of the present invention may include a light-receiving amount adjustment unit that adjusts the displacement information acquisition unit to ensure that the light-receiving amount in the light-receiving element array is at or above a threshold. In this case, it prevents the inability to effectively acquire displacement information due to insufficient light-receiving amount in the light-receiving element array.

[0018] One aspect of the laser processing apparatus of the present invention may include a reference support section that supports a reference object without film or tape material on the laser incident surface side. In this case, by setting the height of the first alignment section relative to the reference object supported by the reference support section, the displacement information obtained at this time can be recorded as reference displacement information by the information recording section.

[0019] In one aspect of the laser processing apparatus of the present invention, if the reference displacement information is recorded by the information recording unit, the first alignment unit may, after actuating the moving mechanism such that the displacement information acquired by the displacement information acquisition unit becomes the reference displacement information, actuate the moving mechanism such that the position of the condenser lens relative to the optical axis of the laser incident surface is aligned with the reference position based on the imaging results obtained by the imaging unit. In this case, the height setting can be performed by the first alignment unit (i.e., the height setting can be performed based on the imaging results of the imaging unit), thereby enabling high-speed height setting.

[0020] In one aspect of the laser processing apparatus of the present invention, the displacement information acquisition unit may acquire displacement information by emitting a measuring laser relative to the laser incident surface and receiving the measuring laser after it has been reflected by the laser incident surface. When a modified region is formed on an object having a transmissive member that is transmissive to both the laser and the measuring laser on the laser incident surface, the second alignment unit calculates an offset based on transmissive member information including information about the thickness and refractive index of the transmissive member. This offset corresponds to the offset of the optical path of the measuring laser with the transmissive member present relative to the optical path of the measuring laser without the transmissive member. Based on the calculated offset, the reference displacement information pre-stored in the information recording unit is modified. Thus, it can also be adapted to objects having a transmissive member (e.g., transparent tape) on the laser incident surface.

[0021] One aspect of the laser processing apparatus of the present invention may include an input unit that accepts input regarding the presence or absence of a transmitting member and information about the transmitting member, and a second alignment unit that determines whether a transmitting member exists based on the input from the input unit, and calculates an offset if it determines that a transmitting member exists. Thus, by using the input from the input unit, it is possible to correspond to an object on which a transmitting member is provided on the laser incident surface.

[0022] The effects of the invention

[0023] Based on the present invention, a laser processing apparatus can be provided that can align the focusing lens with the optical axis of the laser incident surface without being limited by the object being processed. Attached Figure Description

[0024] Figure 1 This is a perspective view of the laser processing apparatus illustrating the implementation method.

[0025] Figure 2 This is a perspective view of the object being mounted on the support platform of the laser processing apparatus in the embodiment.

[0026] Figure 3 yes Figure 1 A cross-sectional view of the XY plane.

[0027] Figure 4 This is a perspective view showing a portion of the laser output section and the laser focusing section of the laser processing apparatus according to the embodiment.

[0028] Figure 5 yes Figure 1 A cross-sectional view of the XY plane.

[0029] Figure 6 yes Figure 5 A cross-sectional view of the VI-VI line.

[0030] Figure 7 yes Figure 6 A cross-sectional view of line VII-VII.

[0031] Figure 8 This is a front view showing the schematic structure of different axis ranging sensors in various implementations.

[0032] Figure 9 This is a diagram showing the focus state of the markings on the caliper plate in an image of the laser incident surface captured by the observation camera of the embodiment.

[0033] Figure 10 This is a flowchart illustrating an example of height setting.

[0034] Figure 11 This is a flowchart illustrating an example of height setting.

[0035] Figure 12 (a) is a front view illustrating the different axis distance sensors used for height setting. Figure 12 (b) indicates the same Figure 12 (a) Front view of different axis ranging sensors.

[0036] Figure 13 This is a diagram showing that the markings on the caliper plate in an image of the laser incident surface taken by the observation camera of the embodiment are invisible.

[0037] Figure 14 This is a flowchart illustrating an example of height setting.

[0038] Figure 15 This is a flowchart illustrating an example of height setting.

[0039] Figure 16This is a schematic top view of the support platform and reference support platform of a modified laser processing apparatus.

[0040] Figure 17 It represents the object and the reference object being supported. Figure 16 A top view showing the state of the support platform and the reference support platform.

[0041] Figure 18 (a) is a flowchart representing an example of height setting. Figure 18 (b) is a flowchart representing an example of height setting.

[0042] Figure 19 This is a flowchart illustrating an example of height setting.

[0043] Figure 20 (a) is a diagram showing the schematic structure of different axis ranging sensors in the modified examples. Figure 20 (b) is a diagram showing the schematic structure of different axis ranging sensors in the modified examples. Figure 20 (c) is a diagram showing the schematic structure of different axis ranging sensors in the modified examples.

[0044] Figure 21 This is a three-dimensional view of a modified laser processing apparatus.

[0045] Figure 22 (a) is a side view of the object without the transparent tape. Figure 22 (b) is a side view of the object on which transparent tape is applied.

[0046] Figure 23 It is a side view of the object, used to illustrate the calculation of the offset.

[0047] Figure 24 This is a flowchart illustrating an example of height setting. Detailed Implementation

[0048] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. The same or equivalent parts will be marked with the same symbols in each drawing, and repeated descriptions will be omitted. Directions orthogonal to each other in the horizontal plane will be designated as the X-axis and Y-axis, and the vertical direction will be designated as the Z-axis.

[0049] like Figure 1 As shown, in the laser processing apparatus 200, a modified region is formed on the object 1 by irradiating it with a laser. The object 1 is a plate-shaped component (e.g., a substrate, wafer, etc.) comprising a semiconductor substrate formed of a semiconductor material and a piezoelectric substrate formed of a piezoelectric material. Figure 2As shown, a predetermined cutting line 5 for cutting the object 1 is provided in the object 1. The predetermined cutting line 5 is a straight, dotted line. When a modified region is formed inside the object 1, the laser is moved relative to the predetermined cutting line 5 while the focusing point (at least a part of the focusing region) is aligned with the inside of the object 1. Thus, the modified region is formed in the object 1 along the predetermined cutting line 5.

[0050] The predetermined cutting line 5 is not limited to a straight line; it can also be a curve, a combination of these in a 3D shape, or specified by coordinates. The predetermined cutting line 5 is not limited to a dashed line; it can also be an actual line drawn on the surface of the object 1. The modified region can be formed continuously or intermittently. The modified region can also be in a row or at points; the key point is that the modified region must be formed at least within the interior of the object 1. Additionally, there is a possibility of cracks forming from the modified region as the starting point; the cracks and modified region can also be exposed on the outer surface (surface, back, or outer peripheral surface) of the object 1. The laser incident surface when forming the modified region is not limited to the surface of the object 1; it can also be the back of the object 1.

[0051] A modified region refers to a region whose density, refractive index, mechanical strength, and other physical properties differ from their surroundings. A modified region can be, for example, a melt-processed region (meaning a region that has been melted and then solidified, a region in a molten state, or a region in a melt-and-solidified state), a cracked region, an insulation-damaged region, a region with a change in refractive index, or a mixture of these. A modified region is characterized by: a density change in the material of object 1 compared to the density of the unmodified region, and a region with lattice defects. In the case that the material of object 1 is monocrystalline silicon, the modified region can also be described as a high dislocation density region.

[0052] The molten treatment region, the refractive index change region, the modified region with a density change compared to the unmodified region, and the region with lattice defects are further examples of regions containing internal cracks (fractures, microcracks) within themselves and at the interface between the modified and unmodified regions. These internal cracks can span the entire modified region, be formed only in a portion, or be formed in multiple portions. Object 1 comprises a substrate made of a crystalline material with a crystalline structure. For example, object 1 comprises a substrate formed of at least one of gallium nitride (GaN), silicon (Si), silicon carbide (SiC), LiTaO3, and sapphire (Al2O3). In other words, 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 can also be either anisotropic or isotropic crystals. Alternatively, object 1 may be a substrate comprising an amorphous material having an amorphous structure, or may include, for example, a glass substrate.

[0053] In this embodiment, a modified region can be formed by creating multiple modified spots (processing marks) along the predetermined cutting line 5. In this case, the modified region is formed by concentrating multiple modified spots. A modified spot is a modified portion formed by irradiation with a single pulse of pulsed laser light (i.e., single-pulse laser irradiation). Examples of modified spots include cracked spots, melt-processed spots, or spots with refractive index changes, or at least a combination of these. For the modified spot, its size and the length of the crack can be appropriately controlled considering the required cutting precision, the required flatness of the cut section, the thickness, type, and crystal orientation of the object 1. In this embodiment, a modified region can be formed by creating modified spots along the predetermined cutting line 5.

[0054] like Figure 1 As shown, the laser processing apparatus 200 includes: an apparatus frame 210, a first moving mechanism 220, a support platform (support part) 230, and a second moving mechanism (moving mechanism) 240. Furthermore, the laser processing apparatus 200 includes: a laser output part 300, a laser focusing part (irradiation part) 400, and a control part 500.

[0055] A first moving mechanism 220 is mounted on a device frame 210. The first moving mechanism 220 includes a first track element 221, a second track element 222, and a movable base 223. The first track element 221 is mounted on the device frame 210. The first track element 221 has a pair of tracks 221a and 221b extending along the Y-axis. The second track element 222 is mounted on the pair of tracks 221a and 221b of the first track element 221 in a manner movable along the Y-axis. The second track element 222 has a pair of tracks 222a and 222b extending along the X-axis. The movable base 223 is mounted on the pair of tracks 222a and 222b of the second track element 222 in a manner movable along the X-axis. The movable base 223 is rotatable about an axis parallel to the Z-axis.

[0056] A support platform 230 is mounted on a movable base 223. The support platform 230 supports object 1. Figure 2 In the example shown, object 1, for example, has multiple functional elements (light-receiving elements such as photodiodes, light-emitting elements such as laser diodes, or circuit elements formed as circuits) arranged in a matrix on the surface side of a substrate made of semiconductor materials such as silicon. When object 1 is supported on support stage 230, for example, surface 1a (the surface on which the multiple functional elements are located) of object 1 is attached to a thin film 12 that is attached to an annular frame 11. Support stage 230 holds frame 11 by clamps and adsorbs thin film 12 by vacuum suction cup stage, thus supporting object 1. On support stage 230, multiple parallel cut-off lines 5a and multiple parallel cut-off lines 5b in object 1 are set in a grid pattern by means of adjacent functional elements (hereinafter also referred to as "grid lines").

[0057] like Figure 1 As shown, the support platform 230 is moved along the Y-axis by actuating the second track element 222 on the first moving mechanism 220. Additionally, the support platform 230 is moved along the X-axis by actuating the movable base 223 on the first moving mechanism 220. Furthermore, the support platform 230 rotates about an axis parallel to the Z-axis by actuating the movable base 223 on the first moving mechanism 220. Thus, the support platform 230 is mounted on the device frame 210, movable along both the X and Y axes and rotatable about an axis parallel to the Z-axis.

[0058] The laser output unit 300 is mounted on the device frame 210. The laser focusing unit 400 is mounted on the device frame 210 via the second moving mechanism 240. The laser focusing unit 400 is moved along the Z-axis direction (the optical axis direction of the focusing lens unit 430 described later) by actuating the second moving mechanism 240. Thus, the laser focusing unit 400 is mounted on the device frame 210 in a manner that allows it to move relative to the laser output unit 300 along the Z-axis direction.

[0059] The control unit 500 consists of a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The control unit 500 controls the operation of each component of the laser processing apparatus 200. Details of the processing performed by the control unit 500 are described below.

[0060] In the laser processing apparatus 200, for example, a modified region is formed inside the object 1 along each predetermined cutting line 5a, 5b as follows: First, the object 1 is supported on the support table 230 with the back surface 1b of the object 1 as the laser incident surface, and each predetermined cutting line 5a of the object 1 is aligned with a direction parallel to the X-axis. The position of the focusing lens unit 430 (described later) relative to the laser incident surface in the Z-axis direction is aligned with a reference position (i.e., a height setting is performed). The laser focusing unit 400 is moved in the Z-axis direction by the second moving mechanism 240 such that the focusing point of the laser L inside the object 1 is located at a position separated from the laser incident surface by only a predetermined distance. The distance between the laser incident surface and the focusing point of the laser L is maintained at a fixed value, and the focusing point of the laser L is moved relative to each predetermined cutting line 5a. Thus, a modified region is formed inside the object 1 along each predetermined cutting line 5a. The laser incident surface is not limited to the back surface 1b and may also be the surface 1a.

[0061] Once the formation of the modified region along each predetermined cutting line 5a is complete, the support platform 230 is rotated by the first moving mechanism 220, aligning each predetermined cutting line 5b of the object 1 with a direction parallel to the X-axis. Height is then set. The laser focusing section 400 is moved by the second moving mechanism 240 such that the focusing point of the laser L inside the object 1 is located at a position separated from the laser incident surface by only a predetermined distance. The distance between the laser incident surface and the focusing point of the laser L is maintained constant, and the focusing point of the laser L is moved relative to each predetermined cutting line 5b. Thus, a modified region is formed inside the object 1 along each predetermined cutting line 5b.

[0062] Thus, in the laser processing apparatus 200, the direction parallel to the X-axis is the processing direction (the scanning direction of the laser L). Furthermore, the relative movement of the focusing points of the laser L along each predetermined cutting line 5a and along each predetermined cutting line 5b is performed by moving the support table 230 along the X-axis direction via the first moving mechanism 220. Additionally, the relative movement of the focusing points of the laser L between each predetermined cutting line 5a and between each predetermined cutting line 5b is performed by moving the support table 230 along the Y-axis direction via the first moving mechanism 220.

[0063] like Figure 3 As shown, the laser output unit 300 includes: a mounting base 301, a cover 302, and multiple reflectors 303 and 304. Furthermore, the laser output unit 300 includes: a laser oscillator (laser source) 310, a baffle 320, a λ / 2 wavelength plate element (output adjustment unit, polarization direction adjustment unit) 330, a polarizing plate element (output adjustment unit, polarization direction adjustment unit) 340, a beam expander (laser parallelization unit) 350, and a reflector element 360.

[0064] Mounting base 301 supports multiple mirrors 303 and 304, a laser oscillator 310, a baffle 320, a λ / 2 wavelength plate element 330, a polarizing plate element 340, a beam expander 350, and a mirror element 360. The multiple mirrors 303 and 304, laser oscillator 310, baffle 320, λ / 2 wavelength plate element 330, polarizing plate element 340, beam expander 350, and mirror element 360 are mounted on the main surface 301a of mounting base 301. Mounting base 301 is a plate-shaped component relative to device frame 210 (…). Figure 1 (Refer to) It is detachable. The laser output unit 300 is mounted on the device frame 210 via the mounting base 301. That is, the laser output unit 300 is detachable from the device frame 210.

[0065] Cover 302 covers multiple mirrors 303 and 304, laser oscillator 310, baffle 320, λ / 2 wavelength plate element 330, polarizing plate element 340, beam expander 350, and mirror element 360 on the main surface 301a of mounting base 301. Cover 302 is detachable from mounting base 301.

[0066] The laser oscillator 310 pulses linearly polarized laser light L along the X-axis. The wavelength of the laser light L emitted from the laser oscillator 310 is any wavelength band included in the range of 500–550 nm, 1000–1150 nm, or 1300–1400 nm. Laser light L in the 500–550 nm wavelength band is suitable, for example, for internal absorption laser processing of substrates made of sapphire. Laser light L in the 1000–1150 nm and 1300–1400 nm wavelength bands is suitable, for example, for internal absorption laser processing of substrates made of silicon. The polarization direction of the laser light L emitted from the laser oscillator 310 is, for example, parallel to the Y-axis. The laser light L emitted from the laser oscillator 310 is reflected by the reflector 303 and incident on the baffle 320 along the Y-axis.

[0067] In the laser oscillator 310, the on / off state of the laser L output is switched as follows: When the laser oscillator 310 is composed of a solid-state laser, the on / off state of the laser L output can be switched rapidly by switching the on / off state of the Q-switches (AOM (Audio-Optical Modulator), EOM (Electro-Optical Modulator), etc.) provided within the resonator. When the laser oscillator 310 is composed of a fiber laser, the on / off state of the laser L output can be switched rapidly by switching the on / off state of the seed laser and the semiconductor laser constituting the amplification (excitation) laser. When the laser oscillator 310 uses an external modulation element, the on / off state of the laser L output can be switched rapidly by switching the on / off state of the external modulation element (AOM, EOM, etc.) provided outside the resonator.

[0068] The baffle 320 opens and closes the optical path of the laser L via a mechanical mechanism. The switching of the output of the laser L from the laser output unit 300 from being ON / OFF is implemented, as described above, by switching the output of the laser L in the laser oscillator 310 from being ON / OFF. However, by providing the baffle 320, it is prevented that, for example, the laser L may be suddenly emitted from the laser output unit 300. The laser L passing through the baffle 320 is reflected by the reflector 304 and sequentially incident along the X-axis onto the λ / 2 wavelength plate element 330 and the polarizing plate element 340.

[0069] The λ / 2 wavelength plate element 330 and the polarizing plate element 340 function as output adjustment units to adjust the output (light intensity) of the laser L. Additionally, the λ / 2 wavelength plate element 330 and the polarizing plate element 340 function as polarization direction adjustment units to adjust the polarization direction of the laser L. Details of these will be described later. The laser L, having passed sequentially through the λ / 2 wavelength plate element 330 and the polarizing plate element 340, is incident along the X-axis direction onto the beam expander 350.

[0070] The beam expander 350 adjusts the optical path of the laser L and parallelizes the laser L. The laser L, having passed through the beam expander 350, is incident on the reflector element 360 along the X-axis.

[0071] The reflector element 360 includes a support base 361 and multiple reflectors 362 and 363. The support base 361 supports the multiple reflectors 362 and 363. The support base 361 is mounted on the mounting base 301 in a manner that allows for position adjustment along the X-axis and Y-axis directions. The reflector 362 reflects the laser L that has passed through the beam expander 350 in the Y-axis direction. The reflector 362 is mounted on the support base 361 in a manner that allows for angle adjustment of its reflecting surface around an axis parallel to, for example, the Z-axis. The reflector 363 reflects the laser L reflected by the reflector 362 in the Z-axis direction. The reflector 363 is mounted on the support base 361 in a manner that allows for angle adjustment of its reflecting surface around an axis parallel to, for example, the X-axis and for position adjustment along the Y-axis direction. The laser L reflected by the reflector 363 is incident on the laser focusing section 400 along the Z-axis direction through an opening 361a formed in the support base 361. Figure 1 (Refer to the above). That is, the emission direction of the laser L emitted from the laser output section 300 is consistent with the moving direction of the laser focusing section 400. As mentioned above, each reflector 362 and 363 has a mechanism for adjusting the angle of the reflecting surface. In the reflector element 360, by implementing: adjusting the position of the support base 361 relative to the mounting base 301, adjusting the position of the reflector 363 relative to the support base 361, and adjusting the angle of the reflecting surface of each reflector 362 and 363, the position and angle of the optical axis of the laser L emitted from the laser output section 300 are consistent with the laser focusing section 400. That is, the multiple reflectors 362 and 363 are a structure for adjusting the optical axis of the laser L emitted from the laser output section 300.

[0072] like Figure 4 As shown, the laser focusing unit 400 has a frame 401. The frame 401 is formed into a cuboid shape with the Y-axis as its long side. A second moving mechanism 240 is mounted on one side 401e of the frame 401. Figure 5 and Figure 7(Refer to reference). A cylindrical light incident section 401a is provided in the frame 401, facing the opening 361a of the reflector element 360 in the Z-axis direction. The light incident section 401a directs the laser L emitted from the laser output section 300 into the frame 401. The reflector element 360 and the light incident section 401a are separated by a distance that prevents them from contacting each other when the laser focusing section 400 is moved along the Z-axis direction by the second moving mechanism 240.

[0073] like Figure 5 and Figure 6 As shown, the laser focusing unit 400 includes a reflector 402 and a dichroic mirror 403. Furthermore, the laser focusing unit 400 includes a reflective spatial light modulator (spatial light modulator) 410, a 4f lens element 420, a focusing lens unit 430, a drive mechanism 440, and a pair of different-axis distance sensors (displacement information acquisition units) 450. The laser focusing unit 400 irradiates the object 1 with laser light L via the focusing lens unit 430.

[0074] A reflector 402 is mounted on the bottom surface 401b of a housing 401, opposite the light incident section 401a in the Z-axis direction. The reflector 402 reflects the laser L incident on the housing 401 via the light incident section 401a in a direction parallel to the XY plane. In the reflector 402, the laser L, parallelized by the beam expander 350 of the laser output section 300, is incident along the Z-axis direction. That is, the laser L is incident on the reflector 402 as parallel light along the Z-axis direction. Therefore, even if the laser focusing section 400 is moved along the Z-axis direction by the second moving mechanism 240, the state of the laser L incident on the reflector 402 along the Z-axis direction can still be maintained at a fixed position. The laser L reflected by the reflector 402 is incident on the reflective spatial light modulator 410.

[0075] A reflective spatial light modulator 410 is mounted at the end 401c of the frame 401 in the Y-axis direction, with the reflective surface 410a facing inwards. The reflective spatial light modulator 410, for example, is a spatial light modulator (SLM) of a reflective liquid crystal on silicon (LCOS), which modulates the laser L and reflects it in the Y-axis direction. The laser L, modulated and reflected by the reflective spatial light modulator 410, is incident on the 4f lens element 420 along the Y-axis direction. Here, in a plane parallel to the XY plane, the angle α formed by the optical axis of the laser L incident on the reflective spatial light modulator 410 and the optical axis of the laser L emitted from the reflective spatial light modulator 410 is an acute angle (e.g., 10–60°). That is, the laser L is reflected at an acute angle along the XY plane by the reflective spatial light modulator 410. This is to suppress the incident angle and reflection angle of the laser L and to suppress the decrease in diffraction efficiency, so as to fully utilize the performance of the reflective spatial light modulator 410.

[0076] The 4f lens element 420 includes: a support 421, a lens 422 on the side of the reflective spatial light modulator 410, a lens 423 on the side of the condenser lens unit 430, and a slit member 424. The support 421 holds a pair of lenses 422, 423 and slit member 424. The support 421 maintains the relative position of the pair of lenses 422, 423 and slit member 424 along the optical axis of the laser L as constant. The pair of lenses 422, 423 form a bilateral telecentric optical system that constitutes the imaging relationship between the reflecting surface 410a of the reflective spatial light modulator 410 and the entrance pupil surface 430a of the condenser lens unit 430. Thus, the image of the laser L in the reflecting surface 410a of the reflective spatial light modulator 410 (the image of the laser L modulated in the reflective spatial light modulator 410) is imaged onto the entrance pupil surface 430a of the condenser lens unit 430. A slit 424a is formed in the slit member 424. The slit 424a is located between lenses 422 and 423, near the focal plane of lens 422. The unwanted portion of the laser L, which is modulated and reflected by the reflective spatial light modulator 410, is blocked by the slit member 424. The laser L, which has passed through the 4f lens element 420, is incident on the dichroic mirror 403 along the Y-axis direction.

[0077] Dichroic mirror 403 reflects most of the laser L (e.g., 95–99.5%) towards the Z-axis and transmits a portion of the laser L (e.g., 0.5–5%) along the Y-axis. Most of the laser L is reflected at right angles by dichroic mirror 403 along the ZX plane. The laser L reflected by dichroic mirror 403 is incident on condenser lens unit 430 along the Z-axis.

[0078] A condenser lens unit 430 is mounted at end 401d (the end opposite to end 401c) of a frame 401 in the Y-axis direction via a drive mechanism 440. The condenser lens unit 430 includes a support 431 and a plurality of condenser lenses 432. The support 431 holds the plurality of condenser lenses 432. The plurality of condenser lenses 432 focus the laser L onto the object 1 supported on the support platform 230. Figure 1 (Refer to). The drive mechanism 440 moves the condenser lens unit 430 along the Z-axis direction by the driving force of the piezoelectric element.

[0079] The different-axis distance measuring sensors 450 are mounted on the end 401d of the frame 401, positioned on either side of the condenser lens unit 430 in the X-axis direction. The different-axis distance measuring sensors 450 use a first measuring laser, corresponding to the object 1 ( Figure 1 The displacement information is obtained by measuring the displacement of the laser incident surface (reference). Different axis ranging sensors 450 emit a first measuring laser (measuring laser) onto the object 1 supported on the support platform 230. Figure 1 The laser incident surface (reference) is used to obtain displacement information of the laser incident surface of object 1 by receiving a first measuring laser reflected from the laser incident surface. Furthermore, different axis ranging sensors 450 can be used, including sensors employing triangulation, laser confocal, white confocal, spectral interferometry, astigmatism, etc.

[0080] The laser focusing unit 400 includes a light distributor 461, a pair of lenses 462 and 463, and a camera 464 for monitoring the intensity distribution of the laser L. The light distributor 461 splits the laser L, which has passed through the dichroic mirror 403, into a reflective component and a transmitted component. The laser L reflected by the light distributor 461 is sequentially incident along the Z-axis onto the pair of lenses 462 and 463 and the camera 464. The pair of lenses 462 and 463 form a bilateral telecentric optical system that creates an imaging relationship between the entrance pupil surface 430a of the focusing lens unit 430 and the imaging surface of the camera 464. Thus, the image of the laser L in the entrance pupil surface 430a of the focusing lens unit 430 is imaged onto the imaging surface of the camera 464. As described above, the image of the laser L in the entrance pupil surface 430a of the focusing lens unit 430 is the image of the laser L modulated in the reflective spatial light modulator 410. Therefore, in the laser processing apparatus 200, the operating state of the reflective spatial light modulator 410 can be grasped by monitoring the imaging results obtained by the camera 464.

[0081] Furthermore, the laser focusing unit 400 includes: a light distributor 471, a lens 472, and a camera 473 for monitoring the optical axis position of the laser L. The light distributor 471 splits the laser L that has passed through the light distributor 461 into a reflected component and a transmitted component. The laser L reflected by the light distributor 471 is sequentially incident along the Z-axis onto the lens 472 and the camera 473. The lens 472 focuses the incident laser L onto the imaging surface of the camera 473.

[0082] Multiple light distributors 461 and 471 are disposed within a cylindrical body 404 extending from the end 401d of the frame 401 along the Y-axis direction. A pair of lenses 462 and 463 are disposed within a cylindrical body 405 erected on the cylindrical body 404 along the Z-axis direction, and a camera 464 is disposed at the end of the cylindrical body 405. A lens 472 is disposed within a cylindrical body 406 erected on the cylindrical body 404 along the Z-axis direction, and a camera 473 is disposed at the end of the cylindrical body 406. The cylindrical bodies 405 and 406 are arranged side by side with each other in the Y-axis direction. Furthermore, the laser L transmitted through the light distributor 471 may be absorbed by a baffle or the like at the end of the cylindrical body 404, or may be used for other suitable applications.

[0083] like Figure 6 and Figure 7 As shown, the laser focusing unit 400 includes: a visible light source 481, multiple lenses 482, a marking plate 483, a reflector 484, a semi-reflective mirror 485, a light distributor 486, a lens 487, an observation camera (image capture unit) 488, and a coaxial ranging sensor 460. The visible light source 481 emits visible light V along the Z-axis. The multiple lenses 482 parallelize the visible light V emitted from the visible light source 481. The marking plate 483 marks the visible light V. The reflector 484 reflects the visible light V, which has been parallelized by the multiple lenses 482, in the X-axis direction. The semi-reflective mirror 485 separates the visible light V reflected by the reflector 484 into a reflected component and a transmitted component. The visible light V reflected by the semi-reflective mirror 485 passes sequentially along the Z-axis through the light distributor 486 and the dichroic mirror 403, and is then irradiated onto the object 1 supported on the support stage 230 via the focusing lens unit 430. Figure 1 Reference).

[0084] Visible light V, irradiated onto object 1, is reflected by the laser incident surface of object 1 and incident on dichroic mirror 403 via condenser lens unit 430, passing through dichroic mirror 403 along the Z-axis. Light distributor 486 splits the visible light V that has passed through dichroic mirror 403 into a reflected component and a transmitted component. Additionally, light distributor 486 reflects the second measuring laser L2 and its reflected light L2R, described later. Visible light V that has passed through light distributor 486 is incident sequentially onto lens 487 and observation camera 488 along the Z-axis via semi-reflective mirror 485. Lens 487 focuses the incident visible light V onto the imaging surface of observation camera 488. Observation camera 488 photographs the laser incident surface of object 1. Observation camera 488 receives visible light V that has been incident on the laser incident surface via datum plate 483 and reflected by the laser incident surface. In the laser processing apparatus 200, the state of the object 1 can be grasped by observing the imaging results obtained by the observation camera 488.

[0085] A reflector 484, a semi-reflector 485, and a light distributor 486 are disposed within a bracket 407 mounted on the end 401d of the frame 401. Multiple lenses 482 and a caliper 483 are disposed within a cylinder 408 erected along the Z-axis on the bracket 407, and a visible light source 481 is disposed at the end of the cylinder 408. A lens 487 is disposed within a cylinder 409 erected along the Z-axis on the bracket 407, and an observation camera 488 is disposed at the end of the cylinder 409. Cylinders 408 and 409 are arranged side-by-side in the X-axis direction. Furthermore, visible light V transmitted along the X-axis direction through the semi-reflector 485, and visible light V reflected in the X-axis direction by the light distributor 486, can be absorbed by baffles or the like provided on the wall of the bracket 407, or can be utilized for suitable purposes.

[0086] A coaxial distance sensor 460 is mounted on the side of the bracket 407. The coaxial distance sensor 460 measures distance by projecting a second measuring laser L2 onto an object 1 supported on a support platform 230. Figure 1The coaxial ranging sensor 460 detects the reflected light L2R of the second measuring laser L2 reflected from the laser incident surface, thereby obtaining displacement information of the laser incident surface of the object 1. The second measuring laser L2 emitted from the coaxial ranging sensor 460 is reflected by the light distributor 486, guided towards the condenser lens unit 430 via the dichroic mirror 403, and reflected by the laser incident surface near the focal point of the condenser lens unit 430. The reflected light L2R returns to the coaxial ranging sensor 460 via the opposite path to the second measuring laser L2. The coaxial ranging sensor 460 utilizes the characteristic that the state of the reflected light L2R changes based on the position of the laser incident surface relative to the condenser lens unit 430 to obtain displacement information of the object 1. For example, the coaxial ranging sensor 460 can be a sensor that utilizes astigmatism or similar methods.

[0087] like Figure 8 As shown, the different axis ranging sensor 450 includes: a light-emitting element 451 such as a laser diode that emits a first measuring laser L1, and a linear photodiode array (light-receiving element array) 453 that receives the first measuring laser L1 reflected from the laser incident surface of the object 1. In the different axis ranging sensor 450, the first measuring laser L1 is emitted from the light-emitting element 451 in a direction inclined relative to the Z-axis. The emitted first measuring laser L1 is focused towards the object 1 by a lens 452 and reflected by the laser incident surface. The reflected first measuring laser L1 travels in a direction inclined relative to the Z-axis and is focused towards the linear photodiode array 453 by a lens 454, receiving light at the spot position of the linear photodiode array 453. This spot position in the linear photodiode array 453 (hereinafter also simply referred to as the "spot position") has a unique relationship with the displacement relative to the laser incident surface. Therefore, different axis ranging sensors 450 obtain information corresponding to the position of the light spot (the position receiving light) as displacement information. Multiple linear photodiode arrays 453 can also be set.

[0088] The control unit 500, based on the imaging results obtained by the observation camera 488, executes a first alignment process that activates the second moving mechanism 240 (i.e., sets the height) to align the position of the condenser lens unit 430 (condenser lens 432) relative to the laser incident surface in the Z-axis direction with a reference position or a predetermined height position away from the reference position at a predetermined distance. The reference position is the Z-axis position of the condenser lens unit 430 when focusing on the markings of the gradation piece 483 in the image of the laser incident surface captured by the observation camera 488 (hereinafter also referred to as the "gradation piece focusing position") (see reference). Figure 9Here, the optical system is adjusted so that the markings on the caliper 483 are focused on the laser incident surface. That is, the focusing position of the photomask is the position when the markings on the caliper 483 are focused on the laser incident surface. In other words, the focusing position of the caliper 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. Furthermore, when the optical system is adjusted so that the markings on the caliper 483 are not focused on the laser incident surface, but at a predetermined height position at a predetermined distance from the laser incident surface, the focusing position of the markings on the caliper 483 is not located on the laser incident surface, but at a predetermined height position at a predetermined distance from the laser incident surface.

[0089] When the control unit 500 aligns the position of the condenser lens unit 430 in the Z-axis direction with the reference position or the specified height position through the first alignment process, it performs information recording process and records the position of the light spot obtained by the distance measuring sensor 450 of different axes as the reference light spot position (reference displacement information) in the storage unit of the control unit 500.

[0090] The control unit 500 performs the second alignment process, so that the position of the light spot obtained by the distance measuring sensor 450 of different axes becomes the reference light spot position, and the second moving mechanism 240 is activated to align the position of the condenser lens unit 430 relative to the laser incident surface in the Z-axis direction with the reference position or the specified height position (i.e., to set the height).

[0091] If, after performing the first alignment process, the control unit 500 cannot identify the focus state of the marking plate 483 on the image of the laser incident surface captured by the observation camera 488, and the position of the reference light spot is not recorded, then it performs an unprocessable judgment process and judges the object 1 as unprocessable.

[0092] The control unit 500 performs a switching process to perform a second alignment process when the focus state of the marking plate 483 cannot be identified on the image of the laser incident surface captured by the observation camera 488, but the reference displacement information is recorded by the information recording unit, after the first alignment process has been performed.

[0093] The control unit 500 performs light-receiving adjustment processing to adjust the distance sensors 450 on different axes so that the light-receiving amount in the linear photodiode array 453 is above a threshold. The adjustment of the distance sensors 450 on different axes can be exemplified by, for example, increasing at least one of the gain and exposure time, or increasing the output of the light-emitting element 451. The control unit 500 comprises a first alignment unit, an information recording unit, a second alignment unit, a non-processable determination unit, a switching unit, and a light-receiving adjustment unit.

[0094] An example illustrating the height setting implemented by the laser processing device 200.

[0095] While referring to Figure 10 process Figure 1 The following describes a processing example for height setting when the reference spot position is recorded in the control unit 500 (i.e., when the reference spot position is not recorded, or when the reference spot position is updated). Furthermore, this height setting is performed during initial adjustment, calibration, and optical axis adjustment.

[0096] First, object 1 is placed on support platform 230. Based on the image of the laser incident surface of object 1 captured by observation camera 488 (the image projected onto caliper 483), the second moving mechanism 240 is driven by control unit 500 to move laser focusing unit 400 in the Z-axis direction so that the height position of condenser lens unit 430 is aligned with the focus position of caliper 483 (step S1).

[0097] For example, in step S1 above, images are acquired by the observation camera 488 at each Z-axis position of the condenser lens unit 430, and image processing is performed on each image to calculate the value (score) of the contrast index of the caliper 483. This contrast value is the position of the laser condenser 400 in the Z-axis direction where the displacement in the Z-axis direction is the maximum (peak value), which is used as the focus position of the caliper. Alternatively, in step S1 above, image processing methods such as pattern matching or Laplace differentiation can also be used.

[0098] Next, the control unit 500 determines whether the contrast peak of the marking piece 483 is optimal (step S2). For example, in step S2, if the peak of the contrast value cannot be detected in step S1, it is determined to be NO (no); if the peak is detected, it is determined to be YES (yes). If step S2 is NO, it is determined that the marking of the marking piece 483 cannot be identified on the image captured by the observation camera 488, and an error is determined to have occurred (step S3). It is determined that the object 1 on the support table 230 cannot be processed by the control unit 500, and the process ends (step S4).

[0099] In this embodiment, since the distance measuring sensor 450, which is not on the same axis as the condenser lens unit 430, is used as a displacement information acquisition unit, the optical axis positions of the distance measuring sensor 450 and the condenser lens unit 430 on the laser incident surface will separate in the processing travel direction. Therefore, when step S2 is YES, the support stage 230 is moved horizontally and the object 1 is moved horizontally (step S5) so that the first measuring laser L1 reaches the position where the marking plate 483 is projected onto the laser incident surface in step S1 (e.g., the center position in the width direction of the grid line). In one example, if the position of the support stage 230 in the X-axis direction in step S1 is [X0], and the position directly below the distance measuring sensor 450 and the condenser lens unit 430 (the optical axis position on the laser incident surface) is only α away from the processing travel direction, then in step S5, the support stage 230 is moved in the X-axis direction so that the position of the support stage 230 in the X-axis direction becomes [X0+α]. Furthermore, this movement of the support platform 230 is not necessary when the displacement information acquisition unit uses a sensor coaxial with the condenser lens unit 430. Next, by recording the position of the light spot detected by the linear photodiode array 453 of the different axis ranging sensors 450 as the reference light spot position in the control unit 500 (step S6), the height setting is completed and the process ends (step S7).

[0100] Then refer to Figure 11 process Figure 1 The following describes a process for height setting where the reference spot position is recorded in the control unit 500. First, the object 1 is placed on the support platform 230. The control unit 500 activates the second moving mechanism 240 to move the condenser lens unit 430 toward the focus position of the caliper plate along the Z-axis, so that the spot position detected by the linear photodiode array 453 becomes the reference spot position (step S11).

[0101] Next, the control unit 500 determines whether the amount of light received by the linear photodiode array 453 for the first measurement laser is optimal (step S12). In step S12, if the amount of light received by the linear photodiode array 453 is above the threshold, it is determined as YES; if the amount of light received by the linear photodiode array 453 is below the threshold, it is determined as NO. If step S12 is NO, the control unit 500 adjusts various parameters of the different axis ranging sensors 450 and returns to step S11 (step S13).

[0102] On the other hand, if step S12 is YES, the control unit 500 activates the second moving mechanism 240, moving the position of the condenser lens unit 430 in the Z-axis direction towards 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. Through the above, the height setting is completed, and the process ends (step S15).

[0103] One example is, for instance Figure 8 When the reference light spot position SP0 shown is recorded in the control unit 500, and the height of a thicker object 1 is set, in step S11 above, if... Figure 12 The detection spot position SP1 is shown in (a). In this case, as... Figure 12 As shown in (b), the laser focusing unit 400 is moved upward by the second moving mechanism 240 in such a way that the light spot position SP1 becomes the reference light spot position SP0. As a result, the focusing lens unit 430 is positioned at the height corresponding to the focus position of the caliper, thus completing the height setting.

[0104] In the laser processing apparatus 200, the height is set based on the image captured by the observation camera 488. At this time, the positions of the light spots obtained by the different axis ranging sensors 450 are recorded as reference light spot positions. Here, for example, if an object 1 with a film (AR vapor-deposited film, etc.) or tape material on the laser incident surface is used, then the image of the laser incident surface captured by the observation camera 488 will show an invisible marking 483. Figure 13 (Refer to). In this case, based on the imaging results of the observation camera 488, it can be determined that there is difficulty in identifying the laser incident surface, and therefore a possibility of difficulty in setting the height. In this regard, in the laser processing apparatus 200, height setting can be performed by actuating the second moving mechanism 240 using the reference light spot position. That is, the laser processing apparatus 200 has two functions: height setting based on the imaging results of the observation camera 488, and height setting based on the detection results of different axis ranging sensors 450. Therefore, height setting is not limited to the object 1.

[0105] In other words, in the laser processing apparatus 200, the spot position of the linear photodiode array 453 and the focus position of the tracing plate are correlated. Even if the thickness of the object 1 is variable, because the relationship between the spot position and the focus position of the tracing plate remains unchanged, the height can still be set even if the laser incident surface cannot be identified from the imaging results of the observation camera 488. In the laser processing apparatus 200, a dataset can be prepared in advance, which includes: height setting using the imaging results of the observation camera 488 and height setting using the detection results of different axis ranging sensors 450. Furthermore, the laser processing apparatus 200 is also effective for situations where identification on the laser incident surface is easy.

[0106] In the laser processing apparatus 200, the observation camera 488 receives visible light V incident on the laser incident surface via the datum plate 483 and reflected by the laser incident surface. The reference position is the focus position of the datum plate. In this case, the height can be set using the datum plate 483.

[0107] In the laser processing apparatus 200, if the focusing state of the caliper 483 cannot be identified on the image of the laser incident surface captured by the observation camera 488, and the position of the reference light spot is not recorded (NO in step S2 above), the object 1 is determined to be unprocessable. Therefore, since the height cannot be set, it can be determined that object 1 is unprocessable.

[0108] In the laser processing apparatus 200, the different axis ranging sensor 450 includes: a light-emitting element 451 that emits light from a first measuring laser L1, and a linear photodiode array 453 that receives light from the first measuring laser L1 after reflection from the laser incident surface. Displacement information that changes according to the displacement of the laser incident surface corresponds to the position of the light spot on the linear photodiode array 453. In this case, the position of the light spot on the linear photodiode array 453 can be used as displacement information for height setting.

[0109] The laser processing apparatus 200 adjusts the distance measuring sensors 450 on different axes so that the amount of light received in the linear photodiode array 453 is above a threshold. In this case, it can prevent the inability to obtain effective spot position information due to insufficient light received by the linear photodiode array 453.

[0110] Furthermore, in the laser processing apparatus 200, if the height setting is performed based on the imaging results of the observation camera 488, and the focus state of the guide plate 483 cannot be identified on the image of the laser incident surface captured by the observation camera 488, and if the control unit 500 records the position of the reference light spot, then the height setting can be switched based on the detection results of different axis ranging sensors 450 (moving towards step S11 above). In this case, the height setting is preferentially performed based on the imaging results of the observation camera 488; if the height setting is not possible, the height setting can be switched to be performed based on the detection results of different axis ranging sensors 450.

[0111] In this embodiment, the height setting process performed by the laser processing apparatus 200 is not limited to, for example... Figure 10 and Figure 11 The example shown. For instance, the height setting can also be implemented as follows. (Refer to...) Figure 14 process Figure 1 The following is an example of another height setting process where the reference light point position is recorded in the control unit 500. First, the object 1 is placed on the support stage 230. Based on the image of the laser incident surface of the object 1 taken by the observation camera 488, the control unit 500 drives the second moving mechanism 240 to move the laser focusing unit 400 in the Z-axis direction so that the height position of the condenser lens unit 430 is aligned with the focus position of the caliper plate (step S21).

[0112] Next, the control unit 500 determines whether the contrast peak of the reticle is optimal (step S22). If step S22 is NO, it is determined that the reticle 483 cannot be identified as being in focus on the image captured by the observation camera 488, and an error has occurred (step S23). As a result, it is determined that the object 1 on the support stage 230 cannot be processed by the control unit 500, and the process ends (step S24). On the other hand, if step S22 is YES, the control unit 500 activates the second moving mechanism 240 to move the position of the condenser lens unit 430 in the Z-axis direction towards a predetermined height position (step S25). The predetermined height position is an arbitrary height position corresponding to the depth of the modified region formed in the object 1. Next, similar to step S5 above, the support stage 230 is moved horizontally to move the object 1 horizontally, so that the first measuring laser L1 reaches the position where the marking piece 483 was projected onto the laser incident surface in step S21 (step S26). Then, the position of the light spot detected by the linear photodiode array 453 of the different axis ranging sensors 450 is recorded as the reference light spot position in the control unit 500 (step S27). Through the above, the height setting is completed, and the process ends (step S28).

[0113] Then refer to Figure 15 process Figure 1 The following describes a processing example where the reference spot position is recorded in the control unit 500. First, the object 1 is placed on the support platform 230. In order to make the spot position detected by the linear photodiode array 453 of the different axis distance sensors 450 the reference spot position, the control unit 500 activates the second moving mechanism 240 to move the condenser lens unit 430 towards a predetermined height position along the Z-axis (step S31).

[0114] Next, the control unit 500 determines whether the light intensity of the first measuring laser L1 after being illuminated by the linear photodiode array 453 is optimal (step S32). If step S32 is NO, the control unit 500 adjusts various parameters of the different axis ranging sensors 450 and returns to step S31 (step S33). On the other hand, if step S32 is YES, the height setting is completed and the process ends (step S34).

[0115] While the above description illustrates one embodiment of the present invention, the present invention is not limited to the embodiments described above.

[0116] Although the above embodiments include different axis ranging sensors 450 as displacement information acquisition units, the displacement information acquisition unit is not particularly limited. For example, the displacement information acquisition unit may also be an astigmatic sensor, in which case it has a 4-segment photodiode. In one example, the coaxial ranging sensor 460 described above may also be used as the displacement information acquisition unit. For example, the displacement information acquisition unit may also be a triangulation sensor, in which case it has a linear photodiode array or a linear image detector. For example, the displacement information acquisition unit may also be an off-center triangulation sensor, in which case it has a linear photodiode array or a linear image detector. For example, the displacement information acquisition unit may also be a confocal sensor, in which case it has a photodiode. For example, the displacement information acquisition unit may also be a spectral interferometer sensor, in which case it has a CCD image detector.

[0117] Figure 16 This is a schematic top view of the support platform 230 and the reference support platform (reference support part) 230K of the laser processing apparatus 600 in a modified example. Figure 17 This indicates that object 1 and reference object 1K are supported on Figure 16 A schematic top view of the support platform 230 and the reference support platform 230K. (See attached image.) Figure 16 and Figure 17As shown, the modified laser processing apparatus 600 may further include a reference support platform 230K for the laser processing apparatus 200.

[0118] A reference support stage 230K supports a reference object 1K that does not contain film or tape material on the laser incident surface side. The reference support stage 230K is arranged side-by-side with the support stage 230. The size of the reference support stage 230K corresponds to the size of the reference object 1K. Here, the reference support stage 230K is smaller than the support stage 230. The reference object 1K is an object whose focus state can be identified by the markings on the caliper plate 483 on the image of the laser incident surface captured by the observation camera 488. The reference object 1K is the object that was determined to be YES in step S2 above.

[0119] In the modified laser processing apparatus 600, where the reference spot position is recorded in the control unit 500, for example, as follows: Figure 18 The height setting is shown in flowchart (a). That is, the reference object 1K is placed on the reference support 230K. The laser focusing unit 400 is moved by driving the first moving mechanism 220 and the second moving mechanism 240 through the control unit 500 so that the optical axis of the condenser lens unit 430 is located on the reference object 1K (step S41). Based on the image of the laser incident surface of the reference object 1K captured by the observation camera 488, the laser focusing unit 400 is moved in the Z-axis direction by driving the second moving mechanism 240 through the control unit 500 so that the height position of the condenser lens unit 430 is aligned with the focus position of the caliper sheet (step S42).

[0120] The control unit 500 activates the second moving mechanism 240, moving the position of the condenser lens unit 430 in the Z-axis direction towards a predetermined height (step S43). Next, similar to step S5, the laser focusing unit 400 is moved horizontally so that the first measuring laser L1 reaches the position where the datum plate 483 was projected onto the laser incident surface in step S42 (step S44). Then, the position of the light spot detected at that time by the linear photodiode array 453 of the different axis ranging sensors 450 is recorded in the control unit 500 as a reference light spot position (step S45). Through the above, the height setting is completed, and the process ends (step S46).

[0121] In the modified laser processing apparatus 600, where the reference spot position is recorded in the control unit 500, for example, as shown in the example... Figure 18The height setting is shown in flowchart (b). First, object 1 is placed on support platform 230. The second moving mechanism 240 is activated by control unit 500 to move condenser lens unit 430 towards a predetermined height position along the Z-axis, so that the position of the light spot detected by the linear photodiode array 453 of different axis ranging sensors 450 becomes the reference light spot position. After completing the height setting, the process ends (step S52).

[0122] Based on the laser processing apparatus 600, the height of the reference object 1K, supported by the reference support stage 230K, is set based on the image captured by the observation camera 488. At this time, the obtained light spot position can be recorded as the reference light spot position. Because the height has been set using the reference object 1K before processing, there is no optical axis offset. By performing the height setting with the reference object 1K once, the need for subsequent height settings can be reduced, thus improving efficiency (reducing the height setting process).

[0123] In the above-described embodiments and variations, it is also possible that, when the reference light spot position is recorded by the control unit 500, the second moving mechanism 240 is activated in such a way that the light spot position obtained by the distance measuring sensor 450 of different axes becomes the reference light spot position, and then the second moving mechanism 240 is activated in such a way that the position of the condenser lens unit 430 relative to the laser incident surface in the Z-axis direction is aligned with the reference position based on the imaging results obtained by the observation camera 488.

[0124] For example, such as Figure 19 As shown in the flowchart, the laser focusing unit 400 is moved arbitrarily along the Z-axis direction so that the focal point of the focusing lens unit 430 is located at the center of the object 1 (step S61). Next, the second moving mechanism 240 is activated by the control unit 500 to move the focusing lens unit 430 along the Z-axis direction so that the position of the light spot detected by the linear photodiode array 453 of the different axis ranging sensors 450 becomes the reference light spot position (step S62). From this state, the focus position of the tracing plate is retrieved, that is, the second moving mechanism 240 is activated to align with the reference position based on the imaging results obtained by the observation camera 488 (step S63). As a result, the height setting can be made faster compared to the case where the height is set without using the light spot position of the different axis ranging sensors 450 (the case where the height is set only from the imaging results of the observation camera 488).

[0125] In the above-described embodiments and variations, for example... Figure 20 of (a), Figure 20 (b) and Figure 20As shown in (c), the different axis ranging sensor 450, or a branching optical system 455, can branch the first measuring laser L1 reflected from the laser incident surface of the object 1 into multiple (in this case, two) branch measuring lasers L11 and L12. A linear photodiode array 453 receives the two branch measuring lasers L11 and L12. The displacement information, which changes according to the displacement of the laser incident surface, corresponds to the intervals H1, H2, and H3 of the light-receiving positions of the two branch measuring lasers L11 and L12 in the linear photodiode array 453. The branching optical system 455 includes lenses 456 and 457. As shown, the intervals of the branch measuring lasers L11 and L12 change towards intervals H1, H2, and H3 by changing the distance (displacement of the laser incident surface) between the laser incident surface and lens 454. In this case, when setting the height, the intervals H1, H2, and H3 of the light-receiving positions of the branch measurement lasers L11 and L12 in the linear photodiode array 453 can be used as displacement information.

[0126] Although the above embodiment includes a reflective spatial light modulator 410, the spatial light modulator is not limited to a reflective type; a transmissive spatial light modulator may also be included. In the above embodiments and variations, the modified region may also be a crystalline region, a recrystallized region, or a gettingting region formed, for example, inside the object 1. A crystalline region refers to a region that maintains the structure of the object 1 before processing. A recrystallized region refers to a region that solidifies from a single crystal or polycrystalline material after evaporation, plasma treatment, or melting. A gettingting region refers to a region that can effectively collect and capture impurities such as heavy metals; it may be formed continuously or intermittently.

[0127] In the above embodiment, although the reference light spot position is stored in the control unit 500, the storage method is not particularly limited. For example, the recorded reference light spot position, as described above, can also be a pre-prepared dataset consisting of the imaging results of the observation camera 488 and the detection results of the different axis ranging sensors 450. This dataset can also include, for example, a coordinate table, which includes: each position in the Z-axis direction of the condenser lens unit 430 (including the focus position of the caliper), and the light spot position of each linear photodiode array 453 corresponding to each position. In this case, the height setting is not limited by the object 1. That is, the process of detecting the position of the laser incident surface is not required when setting the height.

[0128] However, in the following cases, transparent tape 101 (refer to...) Figure 22(b) The object 1, which is placed on the laser incident surface (here, the back surface 1b), is used as the object for laser processing. The transparent tape 101 is a tape-shaped transparent member that is transparent to both the laser L and the first measuring laser L1. This is possible, for example, on the marking sheet 483 (…) on the image of the laser incident surface captured by the observation camera 488. Figure 7 The reference mark will become blurry, making it difficult to set the height.

[0129] The transparency of the transparent tape 101 means that the transparency of the transparent tape 101 is higher than that of the portion of the object 1 other than the transparent tape 101. Transparency means, for example, that the laser L and the first measuring laser L1 can pass through; more specifically, it means that the laser L and the first measuring laser L1 can maintain their intensity. For example, transparency could also mean that the transmittance of the laser L and the first measuring laser L1 is 85% or higher. Object 1, for example, is a silicon through-electrode (TSV) wafer with a thickness of 30 μm.

[0130] Here, as Figure 21 As shown, in the modified example of the laser processing apparatus 700, the control unit 500 calculates an offset based on the tape information (through component information) when a modified area is formed on the object 1 on which the transparent tape 101 is provided. Based on the calculated offset, the control unit 500 changes the pre-stored reference spot position. In other words, the control unit 500 corrects the reference spot position based on the offset to eliminate the positional shift of the reference spot caused by the change in the optical path of the first measuring laser L1 due to the presence of the transparent tape 101.

[0131] The tape information includes information about the thickness and refractive index of the transparent tape 101. The offset corresponds to the optical path of the first measuring laser L1B in the presence of the transparent tape 101. Figure 22 (b) The optical path of the first measuring laser L1A in the absence of transparent tape 101 ( Figure 22 The offset of (a) reference. Control unit 500, specifically, such as Figure 23 As shown, the offset T can be calculated based on the following formula.

[0132] sinα1=(n1 / n2)·sinα

[0133] T=(2d·tanα-2d·(n1·sinα) / (n2·cosα1))·cosα

[0134] n1: Refractive index of the surrounding area, n2: Refractive index of transparent tape 101, α1: Angle of refraction

[0135] The reference light spot position is obtained and stored in advance in the same manner as described above. The reference light spot position is the light spot position obtained by the distance measuring sensor 450 of different axes when the position of the condenser lens unit 430 in the Z-axis direction is aligned with the reference position or the specified height position in the object 1 without the transparent tape 101.

[0136] Return to Figure 21 The laser processing apparatus 700 includes an input unit 701 that accepts input regarding the presence or absence of transparent tape 101 and related tape information. In the input unit 701, for example, the presence or absence of transparent tape 101, as well as the thickness and refractive index of transparent tape 101, are input through selection by the user or other means. The input unit 701 is not particularly limited and can be any type of device. The control unit 500 determines whether transparent tape 101 is present based on the input from the input unit 701. If the control unit 500 determines that transparent tape 101 is present, it calculates an offset based on the tape information input from the input unit 701.

[0137] While referring to Figure 24 process Figure 1 Here is an example of the processing using this laser processing apparatus 700. First, the object 1 is placed on the support stage 230. The control unit 500, based on the input from the input unit 701, determines whether the transparent tape 101 is located on the laser incident surface of the object 1 (step S71). If step S71 is YES, the control unit 500 calculates the offset based on the tape information input from the input unit 701 (step S72). Based on the calculated offset, the control unit 500 changes the pre-stored reference spot position (step S74).

[0138] Next, to make the position of the light spot detected by the linear photodiode array 453 of the different axis ranging sensors 450 a reference light spot position, the control unit 500 activates the second moving mechanism 240 to move the condenser lens unit 430 toward the focusing position of the caliper plate along the Z-axis direction (step S75). The control unit 500 determines whether the amount of light from the first measuring laser L1 after being illuminated by the linear photodiode array 453 is optimal (step S76). If step S76 is YES, the control unit 500 activates the second moving mechanism 240 to move the position of the condenser lens unit 430 in the Z-axis direction toward a predetermined height position (step S77). If step S76 is NO, the control unit 500 adjusts various parameters of the different axis ranging sensors 450 and returns to step S75 (step S78).

[0139] On the other hand, if step S71 is NO, the control unit 500 activates the second moving mechanism 240 to move the condenser lens unit 430 toward the focus position of the caliper along the Z-axis, so that the position of the light spot detected by the linear photodiode array 453 of the different axis ranging sensors 450 becomes the reference light spot position (step S79). The control unit 500 determines whether the amount of light of the first measuring laser L1 after being illuminated by the linear photodiode array 453 is optimal (step S80). If step S80 is YES, the control unit 500 activates the second moving mechanism 240 to move the position of the condenser lens unit 430 in the Z-axis direction toward a predetermined height position (step S81). If step S80 is NO, the control unit 500 adjusts various parameters of the different axis ranging sensors 450 and returns to step S79 (step S82). After step S77 or step S81, the height setting is completed and the process ends (step S83).

[0140] The laser processing apparatus 700 can also achieve the above-mentioned effects. Furthermore, in the laser processing apparatus 700, the different axis ranging sensors 450 receive light from the first measuring laser L1 emitted from the laser incident surface relative to the object 1 and reflected by the laser incident surface, obtaining the position of the light spot (light-receiving position, displacement information) in the linear photodiode array 453. The control unit 500 calculates the offset based on tape information including information about the thickness and refractive index of the transparent tape 101, and changes the pre-stored reference light spot position based on the calculated offset. Thus, it can also be used for the object 1 on which the transparent tape 101 is provided on the laser incident surface. It can also be used for the marking sheet 483 (…). Figure 7 The object 1, which is difficult to identify by the markings of the reference plate 483, becomes a variable that can resolve the deviation in the formation position of the modified region caused by the ambiguity of the markings.

[0141] The laser processing apparatus 700 includes an input unit 701. Based on the input from the input unit 701, the control unit 500 determines whether transparent tape 101 is present, and calculates an offset if transparent tape 101 is present. Thus, the input from the input unit 701 can be used to correct the position of the reference spot related to the offset, corresponding to the object 1 on which transparent tape 101 is provided on the laser incident surface. This provides a switchable (ON / OFF) correction function for the reference spot position related to the offset.

[0142] Furthermore, the component used is not limited to transparent tape 101; it can also be other tape-like, film-like, layered, or block-like components. The calculation for calculating the offset is not limited to other calculations. The calculation for changing the position of the reference spot is not limited to other calculations. Tape information can be input in advance via input unit 701, or the refractive index and thickness of the transparent tape 101 can be measured during each laser processing.

[0143] The above-described embodiments can also be applied to processes such as deburring, slicing, and peeling. The components in the above-described embodiments and variations are not limited to the materials and shapes described above; various materials and shapes can be used. Furthermore, the components in the above-described embodiments and variations can be arbitrarily applied to components in other embodiments or variations.

[0144] Symbol Explanation

[0145] 1...object;

[0146] 101……Transparent tape (through components);

[0147] 200, 600, 700... laser processing equipment;

[0148] 230……Support platform (support section);

[0149] 230K……Reference support platform (reference support section);

[0150] 240……Second moving mechanism (moving mechanism);

[0151] 400… Laser focusing section (irradiation section);

[0152] 430… Condensing lens unit (condensing lens);

[0153] 450... Different axis ranging sensors (displacement information acquisition unit);

[0154] 451...light-emitting element;

[0155] 453… Linear photodiode array (light-receiving element array);

[0156] 483...painting plate;

[0157] 488...Observe the camera (video recording section);

[0158] 500... Control Unit (First Alignment Unit, Information Recording Unit, Second Alignment Unit, Non-Additive)

[0159] (Including the judgment section, switching section, and light intake adjustment section);

[0160] 701... Input Department;

[0161] L...laser;

[0162] L1, L1A, L1B... First measuring laser (measuring laser).

Claims

1. A laser processing apparatus, wherein, It is a laser processing device that uses laser light to irradiate an object and create a modified region. have: Support portion, which supports the object; An irradiation unit that irradiates the object with the laser light via a focusing lens; A moving mechanism that moves the condensing lens along the optical axis of the condensing lens; The camera unit captures images of the laser incident surface of the object; The displacement information acquisition unit uses a measuring laser to acquire displacement information that changes corresponding to the displacement of the laser incident surface; The first alignment unit, based on the imaging results obtained by the imaging unit, moves the moving mechanism in such a way that the position of the condenser lens relative to the laser incident surface in the optical axis direction is aligned with a reference position or a predetermined height position away from the reference position by a predetermined distance; The information recording unit records the displacement information obtained by the displacement information acquisition unit as reference displacement information when the position of the condenser lens in the optical axis direction is aligned with the reference position or the predetermined height position by the first alignment unit. and The second alignment unit actuates the moving mechanism in such a way that the displacement information acquired by the displacement information acquisition unit becomes the reference displacement information, aligning the position of the condenser lens relative to the laser incident surface in the optical axis direction with the reference position or the predetermined height position. The camera unit receives visible light that has been incident on the laser incident surface via the grading plate and reflected by the laser incident surface. The reference position is the position of the condenser lens when the caliper is focused on the image of the laser incident surface captured by the camera unit.

2. The laser processing apparatus as described in claim 1, wherein, It includes an unprocessable determination unit, which determines that an object is unprocessable when, during the processing performed by the first alignment unit, the reference displacement information is not recorded by the information recording unit if the state of the caliper in the image of the laser incident surface captured by the camera unit cannot be identified.

3. The laser processing apparatus as described in claim 1, wherein, It includes a switching unit that, when the reference displacement information is recorded by the information recording unit in the case that the state of focus of the caliper on the image of the laser incident surface captured by the camera unit cannot be identified during the processing performed by the first alignment unit, performs the processing performed by the second alignment unit.

4. The laser processing apparatus as described in claim 2, wherein, It includes a switching unit that, when the reference displacement information is recorded by the information recording unit in the case that the state of focus of the caliper on the image of the laser incident surface captured by the camera unit cannot be identified during the processing performed by the first alignment unit, performs the processing performed by the second alignment unit.

5. The laser processing apparatus according to any one of claims 1 to 4, wherein, The displacement information acquisition unit includes: a light-emitting element that emits the measuring laser, and an array of light-receiving elements that receive the measuring laser reflected from the laser incident surface. The displacement information, which varies with the displacement of the laser incident surface, corresponds to the light-receiving position of the measuring laser in the light-receiving element array.

6. The laser processing apparatus according to any one of claims 1 to 4, wherein, The displacement information acquisition unit includes: a light-emitting element that emits the measuring laser, a branching optical system that branches the measuring laser reflected from the laser incident surface into multiple branched measuring lasers, and an array of light-receiving elements that receive the multiple branched measuring lasers. The displacement information, which varies according to the displacement of the laser incident surface, corresponds to the interval between the light-receiving positions of the multiple branches of the measuring laser in the light-receiving element array.

7. The laser processing apparatus as described in claim 5, wherein, It includes: a light-receiving amount adjustment unit, which adjusts the displacement information acquisition unit in such a way that the light-receiving amount in the light-receiving element array is above a threshold.

8. The laser processing apparatus as described in claim 6, wherein, It includes: a light-receiving amount adjustment unit, which adjusts the displacement information acquisition unit in such a way that the light-receiving amount in the light-receiving element array is above a threshold.

9. The laser processing apparatus according to any one of claims 1 to 4, wherein, It includes: a reference support portion that supports a reference object without film or tape material on the laser incident surface side.

10. The laser processing apparatus as described in claim 5, wherein, It includes: a reference support portion that supports a reference object without film or tape material on the laser incident surface side.

11. The laser processing apparatus according to any one of claims 1 to 4, wherein, When the reference displacement information is recorded by the information recording unit, the first alignment unit moves the moving mechanism in such a way that the displacement information obtained by the displacement information acquisition unit becomes the reference displacement information. Then, based on the imaging results obtained by the imaging unit, the moving mechanism moves in such a way that the position of the condenser lens relative to the laser incident surface in the optical axis direction is aligned with the reference position.

12. The laser processing apparatus as described in claim 5, wherein, When the reference displacement information is recorded by the information recording unit, the first alignment unit moves the moving mechanism in such a way that the displacement information obtained by the displacement information acquisition unit becomes the reference displacement information. Then, based on the imaging results obtained by the imaging unit, the moving mechanism moves in such a way that the position of the condenser lens relative to the laser incident surface in the optical axis direction is aligned with the reference position.

13. The laser processing apparatus according to any one of claims 1 to 4, wherein, The displacement information acquisition unit acquires the displacement information by emitting a measuring laser relative to the laser incident surface and receiving the measuring laser reflected by the laser incident surface. When the modified region is formed on the object having a transmissive member that is transmissive to both the laser and the measuring laser on the laser incident surface, the second alignment portion: Based on information about the transmission member, including information about its thickness and refractive index, an offset is calculated. This offset corresponds to the shift of the optical path of the measuring laser in the presence of the transmission member relative to the optical path of the measuring laser in the absence of the transmission member. Based on the calculated offset, the reference displacement information that was previously stored in the information recording unit is changed.

14. The laser processing apparatus as described in claim 13, wherein, It includes an input unit that accepts input regarding the presence or absence of the transmitting member and information about the transmitting member. The second alignment part: Based on the input from the input unit, it is determined whether the transmitting member exists, and if the transmitting member exists, the offset is calculated.

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