JP2021045784A - Laser processing device and diagnostic method for laser processing device - Google Patents

Abstract

To provide a laser processing device and a diagnostic method for the laser processing device that can easily diagnose presence/absence of occurrence of changes in a state of a laser optical system.SOLUTION: A laser processing device is equipped with: a light-transmissive reference workpiece holding table having a holding surface for holding a reference workpiece manufactured under predetermined manufacturing conditions; a laser optical system which irradiates the reference workpiece with a laser beam, and converges the laser beam inside the reference workpiece in order to form a laser processing region inside the reference workpiece; and a photographic image acquisition part which acquires a photographic image of a contact surface of the reference workpiece contacting the holding surface, through the reference workpiece holding table, in order to acquire crack information of cracks extending from the laser processing region toward the contact surface.SELECTED DRAWING: Figure 4

Description

The present invention relates to a laser processing apparatus that forms a laser processing region inside a work such as a wafer, and a method for diagnosing the laser processing apparatus.

In the semiconductor device manufacturing process, a division process of dividing a product work (wafer) into a plurality of chips is carried out. In this division step, for example, as described in Patent Document 1, a laser is provided by aligning a condensing point from the back surface side of a product work (wafer) in which a plurality of chips are formed on the front surface to the inside of the product work. Laser machining is performed by irradiating light to form a laser machining region inside the product work along the street (scheduled division line) of the product work. Next, in the dividing step, the product work is divided into individual chips through a grinding step of grinding the back surface of the product work after the laser processing step, an expanding step, and the like.

When a laser processing region is formed inside the product work by laser processing, it is said that state changes such as a change in the position of the optical axis of the laser optical system of the laser processing device, a change in the inclination of the optical axis, and uneven light intensity occur. , There is a risk that the laser machined area and cracks will not be formed properly inside the product work. As a result, when an external stress is applied to the product work after laser machining, the cracks extending from the laser machining region do not reach the front surface of the product work, and in the subsequent expanding process, the inserts are divided into individual chips. It may not be done properly.

Patent Document 2 discloses a laser processing apparatus including a transparent table for holding a product work and a camera for photographing the front surface of the product work through the transparent table. In this laser processing device, the front surface of the product work is photographed by a camera through the product work holding table during or after the laser processing, and the laser processing area of the product work is formed based on the photographed image of the front surface. Judging the state.

JP-A-2009-2900052 Japanese Unexamined Patent Publication No. 2015-170697

In order to properly divide the product work into individual product chips in the expanding process, it is important that the crack extending the laser machining area reaches the front surface of the product work. Here, depending on the division process, the crack may not reach the front surface at the time after laser machining, and the crack may reach the front surface only when the grinding process for the back surface of the product work is executed. .. In this case, even if the front surface of the product work is photographed with a camera during or after laser processing as described in Patent Document 2, cracks reach the front surface at the time of this imaging. There is no. Therefore, it is difficult to diagnose from the image taken by this camera whether or not the laser processing region and cracks are properly formed inside the product work, that is, whether or not the state change of the laser optical system has occurred. Is.

Therefore, in the conventional division step, the diagnosis of whether or not the state change of the laser optical system has occurred is executed after the grinding step on the back surface of the product work. Therefore, if the state of the laser optical system is changed, defective products may occur frequently due to laser processing until the above diagnosis is completed.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a laser processing apparatus and a method for diagnosing a laser processing apparatus capable of easily diagnosing the presence or absence of a state change of a laser optical system. ..

The laser processing apparatus for achieving the object of the present invention includes a light-transmitting reference work holding table having a holding surface for holding a reference work manufactured under predetermined manufacturing conditions, and laser light toward the reference work. And the laser optical system that condenses the laser light inside the reference work to form a laser processing area inside the reference work, and the contact surface of the reference work that comes into contact with the holding surface through the reference work holding table. It is provided with a photographed image acquisition unit for acquiring crack information of a crack extending from a laser processing region toward an abutting surface by acquiring the photographed image of the above.

According to this laser processing apparatus, it is possible to diagnose whether or not a state change of the laser optical system has occurred based on a photographed image of the contact surface of the reference work.

In the laser processing apparatus according to another aspect of the present invention, the laser optical system is at a predetermined depth position from the contact surface in the thickness direction of the reference work and corresponds to the assumed value of the crack length. A laser processing region is formed at the position. As a result, it is possible to diagnose whether or not a state change of the laser optical system has occurred based on the captured image of the contact surface of the reference work.

In the laser machining apparatus according to another aspect of the present invention, the reference work holding table is a sub-table different from the product work holding table that holds the product work. As a result, it is possible to diagnose the presence or absence of a state change of the laser optical system without observing (photographing) the product work during laser processing.

In the laser machining apparatus according to another aspect of the present invention, the reference work holding table is held by the product work holding table. As a result, the reference work holding table and the product work holding table can be moved integrally.

In the laser processing apparatus according to another aspect of the present invention, while the laser beam is irradiated from the laser optical system toward the reference work, the laser optical system is moved relative to the reference work to be parallel to the reference work. A first relative movement mechanism for forming a laser processing region inside the reference work along the direction is provided. As a result, it is possible to diagnose whether or not a state change of the laser optical system has occurred based on the captured image of the contact surface of the reference work.

In the laser processing apparatus according to another aspect of the present invention, the product work holding table for holding the product work is provided, and the first relative moving mechanism uses the laser optical system as a reference with respect to the reference work holding table and the product work holding table. When the laser optical system is moved relative to the position facing the work and the position facing the product work by the first relative movement mechanism, the laser beam is directed toward the product work. And condensing the laser beam inside the product work to form a laser processing region inside the product work, the first relative movement mechanism is irradiated with the laser light from the laser optical system toward the product work. During this time, the laser optical system is moved relative to the product work to form a laser processing region inside the product work along a direction parallel to the product work.

In the laser processing apparatus according to another aspect of the present invention, the captured image acquisition unit is arranged at a position facing the other surface on the side opposite to the holding surface of the reference work holding table, and the contact surface is passed through the reference work holding table. It is a camera that shoots. As a result, it is possible to easily acquire a photographed image of the contact surface of the reference work.

In the laser processing apparatus according to another aspect of the present invention, when the surface of the captured image acquisition unit is the other surface on the side opposite to the holding surface of the reference work holding table, the position is different from the position facing the other surface. It is provided with a camera arranged in the above and a relay optical system that guides an image of the contact surface from a position facing the other surface to a position where the camera can take a picture. As a result, it is possible to acquire a photographed image of the contact surface of the reference work regardless of the position and orientation of the camera, so that the degree of freedom in designing the laser processing apparatus can be increased.

In the laser processing apparatus according to another aspect of the present invention, the camera is arranged above the reference work holding table, and the product work holding table for holding the product work, and the product work and the relay optical system. The camera is provided with a second relative movement mechanism that moves the camera relative to a shooting position for shooting the product work and a shooting position for shooting an image of the contact surface guided by the relay optical system. As a result, it is possible to acquire a photographed image of the contact surface of the reference work using the existing camera of the laser processing apparatus, so that the cost of the laser processing apparatus can be reduced.

The laser processing apparatus according to another aspect of the present invention includes a display unit that displays a captured image acquired by the captured image acquisition unit. As a result, the operator can diagnose whether or not a state change of the laser optical system has occurred based on the captured image displayed on the display unit.

The diagnostic method of the laser processing apparatus for achieving the object of the present invention includes a holding step of holding a reference work manufactured under predetermined manufacturing conditions on a holding surface of a light transmitting reference work holding table, and a reference. Through the laser processing area formation step of irradiating the work with laser light from the laser optical system and condensing the laser light inside the reference work to form the laser processing area inside the reference work, and through the reference work holding table. It has a captured image acquisition step of acquiring crack information of a crack extending from a laser processing region toward the contact surface by acquiring a captured image of the contact surface of the reference work that abuts on the holding surface.

In the method for diagnosing a laser machining apparatus according to another aspect of the present invention, in the laser machining region forming step, it is assumed that the depth position is predetermined from the contact surface in the thickness direction of the reference work and the length of the crack is assumed. A laser machining region is formed at a depth position corresponding to the value.

In the method for diagnosing a laser processing apparatus according to another aspect of the present invention, the laser optical system is moved relative to the reference work while the laser beam is being irradiated from the laser optical system toward the reference work. It has a relative movement step that forms a laser machining region inside the reference workpiece along a direction parallel to.

INDUSTRIAL APPLICABILITY According to the present invention, the presence or absence of a state change of the laser optical system can be easily diagnosed.

It is a perspective view of the laser processing apparatus of 1st Embodiment. It is sectional drawing of the product work and the reference work. It is the schematic of the chuck table and the processing unit. It is a schematic diagram of a sub-table and a BHC photographing system. It is a functional block diagram of a control device. It is explanatory drawing for demonstrating the formation of the laser processing area in the product work by laser processing. It is explanatory drawing for demonstrating the formation of the laser processing area in the reference work by laser processing. It is a front view of the front surface of the reference work after laser processing. It is a flowchart which shows the flow of the diagnostic processing of a laser optical system by a laser processing apparatus, more specifically, the acquisition and display processing of the front surface photographed image of a reference work. It is the schematic of the laser processing apparatus of 2nd Embodiment. It is the schematic of the laser processing apparatus of 3rd Embodiment.

[Structure of Laser Machining Machine of First Embodiment]
FIG. 1 is a perspective view of the laser processing apparatus 10 of the first embodiment. As shown in FIG. 1, the laser machining apparatus 10 performs laser machining on the product work 12 and the reference work 14. The laser machining apparatus 10 includes a chuck table 20 (Xθ stage), a machining unit 22, a subtable 24, a BHC imaging system 26, and a control device 28 (see FIG. 3). The XYZ directions in the drawing are orthogonal to each other, of which the X and Y directions are horizontal directions, and the Z direction is the vertical direction (thickness direction of the product work 12 and the reference work 14). The θ direction is a rotation direction with the Z direction as the rotation axis.

FIG. 2 is an enlarged cross-sectional view of the product work 12 and the reference work 14. As shown by reference numeral 2A in FIG. 2, the product work 12 is a silicon wafer on which a plurality of chips (not shown) are formed. The product work 12 has a front surface 12a that abuts on the holding surface 20a (see FIG. 3) of the chuck table 20, which will be described later, and a back surface 12b that is the opposite surface.

Although not shown, the front surface 12a is divided into a plurality of areas by a plurality of streets arranged in a grid pattern. A device layer 12c constituting a chip is provided in each region. The laser machining apparatus 10 forms a laser machining region 110 (see FIG. 6) inside the product work 12 along a plurality of scheduled division lines set on each street.

As shown by reference numeral 2B in FIG. 2, the reference work 14 is used for diagnosis (evaluation) of the laser optical system 22a shown in FIG. 3 described later. The reference work 14 is different from the product work 12, and is a silicon plate (wafer) manufactured under predetermined manufacturing conditions (standards). The manufacturing conditions include the thickness, the surface roughness of the front surface (front surface 14a and back surface 14b), the dope ratio, the crystal orientation, and the like. The front surface 14a is the contact surface of the present invention that abuts on the holding surface 24a of the sub-table 24 described later, and the back surface 14b is the surface opposite to the front surface 14a. The laser machining apparatus 10 forms a laser machining region 110 (see FIG. 7) inside the reference work 14 along the Y direction.

FIG. 3 is a schematic view of the chuck table 20 and the processing unit 22. In FIG. 3, the sub-table 24 and the BHC photographing system 26 are not shown.

As shown in FIG. 3 and FIG. 1 described above, the chuck table 20 corresponds to the product work holding table of the present invention, and the holding surface on which the product work 12 is arranged and in contact with the front surface 12a thereof. Has 20a. A plurality of suction holes (not shown) are formed on the holding surface 20a. Each suction hole communicates with the table suction source 30. A table drive mechanism 32 is connected to the chuck table 20.

As the suction source 30 for the table, for example, a suction pump is used. The table suction source 30 sucks air from each suction hole (not shown) of the holding surface 20a under the control of the control device 28 described later. As a result, the front surface 12a of the product work 12 is sucked and held by the holding surface 20a. In other words, the product work 12 is sucked and held on the holding surface 20a so that the back surface 12b of the product work 12 faces the processing unit 22.

The table drive mechanism 32 has a configuration in which a known linear motion mechanism (linear actuator or the like) and a rotation mechanism (electric motor or the like) are combined. The table drive mechanism 32 moves the chuck table 20 in the X direction and rotates it in the θ direction under the control of the control device 28 described later.

The processing unit 22 includes a laser optical system 22a and an infrared microscope 22b. The processing unit 22 is arranged on the upper side in the Z direction of the chuck table 20 and the sub-table 24 described later. Further, a unit drive mechanism 34 is connected to the processing unit 22.

The unit drive mechanism 34 is a known linear motion mechanism (linear actuator or the like), and moves the machining unit 22 in the Y direction and the Z direction, respectively, under the control of the control device 28 described later.

The laser optical system 22a (also referred to as a laser head or a laser engine) irradiates the laser beam L toward the back surface 12b of the product work 12 or the back surface 14b of the reference work 14 under the control of the control device 28 described later. The laser optical system 22a includes a laser light source 40, a beam expander 42, a mirror 44, a λ / 2 wave plate 46, a spatial light modulator 48, a mirror 50, a mirror 52, a lens 54, a mirror 56, a mirror 58, a lens 60, and the like. A condenser lens 62 is provided. The configuration of the laser optical system 22a is not limited to the configuration shown in FIG. 3, and various configurations used for laser processing of the product work 12 may be adopted.

The laser light source 40 emits the laser beam L for laser processing of the product work 12 and the reference work 14 toward the beam expander 42. Since the type of laser light L is a known technique, a specific description thereof will be omitted here.

The beam expander 42 expands the laser beam L incident from the laser light source 40 to an appropriate beam diameter for phase modulation by the spatial light modulator 48 described later. The laser beam L emitted from the beam expander 42 enters the spatial light modulator 48 via the mirror 44 and the λ / 2 wave plate 46.

As the spatial light modulator 48, for example, a spatial light modulator (SLM: Spatial Light Modulator) of a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) is used. The spatial light modulator 48 modulates the laser beam L incident from the λ / 2 wave plate 46 by presenting a predetermined hologram pattern under the control of the control device 28. As a result, the aberration of the laser beam L is corrected so that the aberration of the laser beam L focused inside the product work 12 or the reference work 14 is equal to or less than a predetermined aberration. Since the configuration and function of the spatial light modulator 48 are also known techniques, specific description thereof will be omitted here.

The laser light L modulated by the spatial light modulator 48 passes through the mirror 50, the mirror 52, the lens 54, the mirror 56, the mirror 58, and the lens 60, and is condensed by the condenser lens 62. The condenser lens 62 is positioned in the Z direction by a lens moving mechanism (not shown). This lens moving mechanism adjusts the Z-direction position of the condensing point of the laser beam L by adjusting the Z-direction position of the condensing lens 62 under the control of the control device 28. Reference numeral A1 in FIG. 3 is an optical axis of the condenser lens 62, that is, an irradiation axis of the laser optical system 22a.

The infrared microscope 22b (also referred to as an infrared photographing optical system) photographs the product work 12 held on the chuck table 20 from the back surface 12b side thereof. The infrared microscope 22b is fixed to the laser optical system 22a and moves integrally with the laser optical system 22a.

The infrared microscope 22b includes an illumination light source 64, a half mirror 66, an objective lens 68, an infrared camera 70, and the like.

As the illumination light source 64, for example, an LD (Laser Diode) light source, an SLD (Super Luminescent Diode) light source, or the like is used. Under the control of the control device 28 described later, the illumination light source 64 outputs illumination light in the wavelength range transmitted through the product work 12, for example, infrared light in the infrared region (including the near infrared region) toward the half mirror 66. To do.

The half mirror 66 reflects a part of the illumination light incident from the illumination light source 64 toward the objective lens 68. As a result, the illumination light is focused on the back surface 12b of the product work 12 by the objective lens 68. The Z-direction position of the focusing point of the illumination light focused by the objective lens 68 is adjusted by moving the objective lens 68 in the Z direction by a lens moving mechanism (not shown). Reference numeral A2 in FIG. 3 is an optical axis of the objective lens 68, that is, a photographing optical axis (observation optical axis) of the infrared microscope 22b.

A part of the reflected light of the illumination light reflected by the product work 12 passes through the half mirror 66 and enters the infrared camera 70.

The infrared camera 70 includes an image sensor (not shown) having sensitivity to the wavelength range of infrared light, and under the control of a control device 28 described later, the product work 12 is photographed and the product work 12 is photographed. The infrared captured image 71, which is a captured image, is output. For example, when an image is taken by the infrared camera 70 with the objective lens 68 focused on the inside of the product work 12, the internal state of the product work 12 can be confirmed based on the infrared photographed image 71. Further, when an image is taken by the infrared camera 70 with the objective lens 68 focused on the back surface 12b or the front surface 12a of the product work 12, the back surface 12b or the front surface is taken based on the infrared image 71. The state of 12a can be confirmed.

The infrared camera 70 outputs an infrared photographed image 71 (image data) of the product work 12 to the control device 28. The control device 28 causes the monitor 73 to display an infrared photographed image 71 of the inside, the back surface 12b, or the front surface 12a of the product work 12 input from the infrared camera 70.

As the infrared camera 70, for example, a camera having high sensitivity in the near infrared region (near infrared camera) represented by an InGaAs (indium gallium arsenide) camera is preferably used.

The optical axis A2 of the infrared microscope 22b is located at a position shifted in one direction in the X direction with respect to the optical axis A1 of the laser optical system 22a. As a result, the infrared microscope 22b can photograph the product work 12 on the same division schedule line as the laser processing position of the product work 12 by the laser optical system 22a.

FIG. 4 is a schematic view of the sub-table 24 and the BHC photographing system 26. In FIG. 4, the chuck table 20 and the processing unit 22 are not shown.

As shown in FIG. 4 and FIG. 1 described above, the sub-table 24 corresponds to the reference work holding table of the present invention, and is a light-transmitting material such as glass, more specifically described later. It is made of a material that transmits the illumination light used in the BHC photographing system 26.

The sub-table 24 has a holding surface 24a on which the reference work 14 is arranged and in contact with the front surface 14a thereof. A plurality of suction grooves 24b are formed on the holding surface 24a. Each suction groove 24b communicates with the suction source 36 for the sub-table.

As the suction source 36 for the sub-table, a suction pump is used in the same manner as the suction source 30 for the table described above. The sub-table suction source 36 sucks air from each suction groove 24b of the holding surface 24a under the control of the control device 28 described later. As a result, the front surface 14a of the reference work 14 is sucked and held by the holding surface 24a. In other words, the reference work 14 is sucked and held on the holding surface 24a so that its back surface 14b faces the processing unit 22.

The sub-table 24 is positioned so as to overlap a part of the moving range of the machining unit 22 in the Y direction when viewed from the Z direction side (upper side), and overlaps with the moving range of the chuck table 20 in the X direction. It is provided in a position where it does not become. That is, the sub-table 24 is provided at a position that does not hinder the movement of the chuck table 20 in the X direction and at a position where laser machining by the laser optical system 22a is possible.

Therefore, under the control of the control device 28 described later, the unit drive mechanism 34 is driven to adjust the Y-direction position of the machining unit 22, so that the laser optical system 22a faces the reference work 14 (back surface 14b). That is, the reference work 14 can be set at a position where laser machining is possible. Further, the laser optical system 22a can be moved relative to the reference work 14 in the Y direction during laser machining of the reference work 14.

The BHC photographing system 26 corresponds to the photographed image acquisition unit of the present invention. The BHC photographing system 26 is arranged at a position facing the lower surface 24c (corresponding to the other surface of the present invention) on the side opposite to the holding surface 24a of the sub-table 24, that is, on the lower side of the sub-table 24 in the Z direction. The BHC photographing system 26 photographs the front surface 14a of the reference work 14 through the light transmissive subtable 24, and more specifically, the backside half cut (BHC) appearing on the front surface 14a. To shoot. The BHC is a crack 112 extending toward the front surface 14a side from the laser processing region 110 formed inside the reference work 14, and the front surface is shown in detail in FIG. 7 described later. The crack 112 that has reached 14a.

The BHC photographing system 26 includes a microscope 72, an illumination light source 74, and a camera 76. Further, the BHC photographing system 26 of the present embodiment has a wide angle of view capable of photographing a wide range (a certain range or more) of the front surface 14a.

The microscope 72 has a shape extending in the Z direction. An illumination light source 74 is attached to the side surface of the microscope 72, and a camera 76 is attached to the bottom surface on the lower side in the Z direction. Further, the microscope 72 is provided with a half mirror 72a and an objective lens 72b.

The half mirror 72a is arranged at a position facing both the microscope 72 and the illumination light source 74.

The objective lens 72b is arranged on the upper side of the half mirror 72a in the Z direction. The focal position of the objective lens 72b is aligned with the holding surface 24a of the sub-table 24, that is, the front surface 14a of the reference work 14. Reference numeral A3 in FIG. 4 is an optical axis of the objective lens 72b, that is, a photographing optical axis (observation optical axis) of the BHC photographing system 26. The optical axis A3 is adjusted in position so as to coincide with, for example, the center position of the subtable 24 in the XY direction.

As the illumination light source 74, for example, a halogen light source, an LED (light emitting diode) light source, an LD light source, an SLD light source, or the like is used. Under the control of the control device 28 described later, the illumination light source 74 emits illumination light in the wavelength range transmitted through the subtable 24, for example, white light or infrared light (near infrared light) toward the half mirror 72a. ..

The half mirror 72a reflects a part of the illumination light incident from the illumination light source 74 toward the objective lens 72b. As a result, the illumination light is focused by the objective lens 72b on the front surface 14a of the reference work 14 through the sub-table 24. Then, a part of the reflected light of the illumination light reflected by the front surface 14a passes through the half mirror 72a and is incident on the camera 76.

The camera 76 includes an image sensor (not shown) having sensitivity to the wavelength range of the illumination light emitted from the illumination light source 74. The camera 76 photographs the front surface 14a of the reference work 14 through the sub-table 24 under the control of the control device 28 described later, and is a photographed image of the front surface 14a. 78 is output to the control device 28. The control device 28 causes the monitor 73 to display the front surface photographed image 78 input from the camera 76.

In order to photograph an arbitrary position of the holding surface 24a of the sub-table 24, that is, an arbitrary position of the front surface 14a of the reference work 14 with the camera 76, either the sub-table 24 or the BHC photographing system 26 is used. A relative movement mechanism for relative movement in the XY direction with respect to the other may be provided. As a result, even when the angle of view of the BHC photographing system 26 is narrow, by moving one of them relative to the other in the XY direction, the BHC photographing system 26 can photograph a wide range of the front surface 14a.

[Function of the control device of the first embodiment]
FIG. 5 is a functional block diagram of the control device 28. As shown in FIG. 5, the control device 28 includes the above-mentioned laser optical system 22a, infrared microscope 22b, BHC photographing system 26, table suction source 30, table drive mechanism 32, unit drive mechanism 34, and sub-table suction. In addition to the source 36 and the monitor 73, the operation unit 75 is connected. As the operation unit 75, a known keyboard, mouse, operation buttons, touch panel, or the like is used.

The control device 28 is composed of an arithmetic unit such as a personal computer, and includes an arithmetic circuit composed of various processors, memories, and the like. Various processors include CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), and programmable logic devices [for example, SPLD (Simple Programmable Logic Devices), CPLD (Complex Programmable Logic Device), And FPGA (Field Programmable Gate Arrays)] and the like. The various functions of the control device 28 may be realized by one processor, or may be realized by a plurality of processors of the same type or different types.

The control device 28 functions as a general control unit 80, a suction control unit 82, a movement control unit 84, a laser control unit 86, an imaging control unit 88, and a display control unit 90 by executing a control program (not shown). It should be noted that what is described as "-part" of the control device 28 may be "-circuit", "-device", or "-equipment". That is, what is described as "~ part" may be composed of firmware, software, hardware, or a combination thereof.

The suction control unit 82 controls the drive of the table suction source 30 and the sub-table suction source 36. When the suction control unit 82 inputs the suction operation or the suction release operation of the product work 12 by the operation unit 75, the suction control unit 82 drives or stops the drive suction source 30 for the table. Further, the suction control unit 82 drives or stops the suction source 36 for the sub-table when the suction operation or the suction release operation of the reference work 14 is input by the operation unit 75.

The movement control unit 84 drives the table drive mechanism 32 and the unit drive mechanism 34 during laser machining of the product work 12 and laser machining of the reference work 14 under the control of the integrated control unit 80 to drive the chuck table. The machining unit 22 is moved relative to the 20 and the sub-table 24.

Under the control of the integrated control unit 80, the movement control unit 84 drives the table drive mechanism 32 and the unit drive mechanism 34, respectively, during laser machining of the product work 12, and the machining unit 22 (laser optical system 22a and infrared microscope 22b). Is integrally moved relative to the product work 12 in the XYZ direction and the θ direction.

By moving the machining unit 22 relative to the product work 12 in this way, the laser optical system 22a is positioned at a position facing the product work 12 before laser machining of the product work 12, and more specifically, laser optics. The optical axis A1 of the system 22a can be aligned with the machining start position (one end of the scheduled division line) of the product work 12. Further, the laser optical system 22a can be relatively moved in the X direction with respect to the product work 12 during the laser processing of the product work 12. Further, before the laser machining of the product work 12, the optical axis A2 of the infrared microscope 22b can be aligned with the alignment reference (not shown) of the product work 12. Therefore, the table drive mechanism 32 and the unit drive mechanism 34 function as the first relative movement mechanism of the present invention during laser machining of the product work 12.

Under the control of the integrated control unit 80, the movement control unit 84 drives the unit drive mechanism 34 during laser machining of the reference work 14, and causes the machining unit 22 (laser optical system 22a) to move in the Y direction with respect to the reference work 14. Move relative to each other. As a result, the laser optical system 22a is positioned at a position facing the reference work 14 before the laser machining of the reference work 14, and more specifically, the optical axis A1 of the laser optical system 22a is positioned at an arbitrary machining start position of the reference work 14. Can be aligned with. Further, the laser optical system 22a can be moved relative to the reference work 14 in the Y direction during laser machining of the reference work 14. Therefore, the unit drive mechanism 34 functions as the first relative movement mechanism of the present invention during laser machining of the reference work 14.

The laser control unit 86 controls the emission of the laser light L by the laser light source 40 and the modulation of the laser light L by the spatial light modulator 48 under the control of the general control unit 80, so that the product work by the laser optical system 22a Laser processing of 12 and the reference work 14 is performed. Since the modulation control of the laser beam L by the spatial light modulator 48 is a known technique, a specific description thereof will be omitted.

Under the control of the integrated control unit 80, the imaging control unit 88 controls the infrared microscope 22b during laser machining of the product work 12, that is, the emission of the illumination light by the illumination light source 64 and the imaging of the product work 12 by the infrared camera 70. .. Further, the photographing control unit 88 controls the BHC photographing system 26 when the laser processing of the reference work 14 is completed under the control of the integrated control unit 80, that is, the emission of the illumination light by the illumination light source 74 and the reference by the camera 76. Controls the shooting of the front surface 14a of the work 14.

The display control unit 90 controls the display of the monitor 73 under the control of the overall control unit 80. The display control unit 90 causes the monitor 73 to display the infrared image 71 captured by the infrared microscope 22b during the laser machining of the product work 12. Further, the display control unit 90 causes the monitor 73 to display the front surface photographed image 78 photographed by the BHC photographing system 26 at the time of laser processing of the reference work 14. Further, the display control unit 90 causes the monitor 73 to display various setting screens of the laser processing device 10.

By executing the control program described above, the integrated control unit 80 functions as an alignment detection unit 96, a first laser machining control unit 98, a second laser machining control unit 100, and an image acquisition control unit 102.

The alignment detection unit 96 operates when the laser machining start operation of the product work 12 is input to the operation unit 75, or automatically operates when a new product work 12 is held on the chuck table 20. The alignment detection unit 96 controls each part of the laser processing apparatus 10 to perform alignment detection for detecting the position and orientation of the product work 12 (scheduled division line) held on the chuck table 20.

First, the alignment detection unit 96 drives the table drive mechanism 32 and the unit drive mechanism 34 to move the infrared microscope 22b relative to the imageable imaging position of the alignment reference (street, recognition mark, etc.) of the product work 12. .. After this movement, the alignment detection unit 96 controls the infrared microscope 22b via the imaging control unit 88 to illuminate the product work 12 with the illumination light source 64 and photograph the alignment reference of the product work 12 with the infrared camera 70. Let it run. As a result, the infrared camera 70 acquires the infrared image 71 of the product work 12, and the infrared image 71 is output from the infrared camera 70 to the alignment detection unit 96.

Next, the alignment detection unit 96 detects the alignment reference in the infrared image 71 based on the infrared image 71 input from the infrared camera 70 by a known image recognition method, so that the line to be divided of the product work 12 is divided. Detects position and orientation. Then, the alignment detection unit 96 outputs the detection result of the position and orientation of the scheduled division line of the product work 12 to the first laser machining control unit 98 as the alignment detection result.

The first laser machining control unit 98 operates after the alignment detection by the alignment detection unit 96 is completed. The first laser machining control unit 98 controls the table drive mechanism 32, the unit drive mechanism 34, and the laser optical system 22a via the movement control unit 84 and the laser control unit 86, and for each scheduled division line of the product work 12. In addition, laser machining is performed to form a laser machining region 110 (see FIG. 6) inside the product work 12 along the planned division line.

Specifically, the first laser machining control unit 98 drives the table drive mechanism 32 and the unit drive mechanism 34 via the movement control unit 84 based on the alignment detection result by the alignment detection unit 96, and divides the laser machining schedule. The scheduled line is oriented parallel to the X direction, and the optical axis A1 of the laser optical system 22a is aligned with one end of the scheduled division line.

FIG. 6 is an explanatory diagram for explaining the formation of the laser processing region 110 in the product work 12 by laser processing. Reference numeral 6A in FIG. 6 is a cross-sectional view taken along the Y direction of the product work 12, and reference numeral 6B in FIG. 6 is a cross-sectional view taken along the X direction of the product work 12.

As shown by reference numerals 6A and 6B in FIG. 6, the first laser machining control unit 98 controls the laser optical system 22a after the above-mentioned alignment is completed, and transfers the laser light L to the front surface 12a of the product work 12. The laser processing region 110 is formed at the position of the condensing point P1 by condensing the light on the condensing point P1 at the predetermined depth position d1.

Next, the first laser machining control unit 98 drives the table drive mechanism 32 via the movement control unit 84 to move the chuck table 20 in the X direction. As a result, the laser optical system 22a is relatively moved in the X direction with respect to the product work 12 in a state where the laser beam L is focused on the condensing point P1, that is, the laser optical system 22a is moved along the scheduled division line. It is moved relative to the product work 12 in the X direction. As a result, the laser machining region 110 is formed inside the product work 12 along the planned division line. Further, when the laser processing region 110 is formed, cracks 112 are generated in the thickness direction (Z direction) of the product work 12 starting from the laser processing region 110.

In laser machining on such a product work 12, the crack 112 extending from the laser machining region 110 toward the lower side in the Z direction (front surface 12a side) does not reach the front surface 12a. Then, when an external stress is applied to the back surface 12b of the product work 12 after laser machining by grinding, chemical etching, or the like, the crack 112 reaches the front surface 12a.

For example, when the number of layers in the laser processing region 110 is one, the first laser processing control unit 98 drives the unit drive mechanism 34 via the movement control unit 84 to divide the laser optical system 22a into a scheduled line. Relatively move in the Y direction by a distance corresponding to the pitch interval of. As a result, alignment is performed so that the optical axis A1 of the laser optical system 22a is aligned with one end of the second scheduled division line.

Then, the first laser processing control unit 98 controls the table drive mechanism 32 and the laser optical system 22a via the movement control unit 84 and the laser control unit 86, and the laser light L of the laser optical system 22a with respect to the focusing point P1. And the movement of the chuck table 20 in the X direction are executed. As a result, the laser machining region 110 is formed inside the product work 12 along the second scheduled division line.

Similarly, the laser machining region 110 is formed inside the product work 12 along all the scheduled division lines. Next, the first laser machining control unit 98 drives the table drive mechanism 32 via the movement control unit 84 to rotate the chuck table 20 by 90 °, and then repeatedly executes the above-mentioned series of processes. As a result, the laser processing region 110 is formed inside the product work 12 along the grid-like division schedule line.

When the product work 12 is thick, the first laser machining control unit 98 forms, for example, a two-layer laser machining region 110 inside the product work 12 along the planned division line. In this case, the first laser machining control unit 98 continuously forms the two layers of the laser machining region 110 for each scheduled division line.

Returning to FIG. 5, the second laser machining control unit 100 operates when the laser machining start operation of the reference work 14 is input to the operation unit 75, or when a new reference work 14 is held in the sub-table 24. It works automatically. The second laser machining control unit 100 controls the unit drive mechanism 34 and the laser optical system 22a via the movement control unit 84 and the laser control unit 86, and lasers inside the reference work 14 along the Y direction. Laser machining is performed to form the machining area 110 (see FIG. 7).

First, the second laser machining control unit 100 drives the unit drive mechanism 34 via the movement control unit 84 based on the position coordinates of the known subtable 24 to move the machining unit 22 in the Y direction. The optical axis A1 of the laser optical system 22a is aligned with, for example, the center position of the holding surface 24a of the subtable 24. As a result, the laser optical system 22a is moved to a position facing the back surface 14b of the reference work 14 on the sub-table 24. In the laser machining with respect to the reference work 14, the formation position of the laser machining region 110 in the XY direction is not particularly limited, so that the method of aligning the laser optical system 22a with the reference work 14 in the XY direction is not particularly limited. Further, this alignment may be performed manually.

FIG. 7 is an explanatory diagram for explaining the formation of the laser processing region 110 in the reference work 14 by laser processing. Note that reference numeral 7A in FIG. 7 is a cross-sectional view taken along the X direction of the product work 12 during laser machining, similarly to reference numeral 6B in FIG. 6, which is shown as a comparative example. Further, reference numeral 7B in FIG. 7 is a cross-sectional view taken along the Y direction of the reference work 14 during laser machining.

As shown in FIG. 7 and FIG. 5 described above, the second laser processing control unit 100 controls the laser optical system 22a after the alignment between the laser optical system 22a and the reference work 14 is completed, and the laser light L Is focused from the front surface 14a of the reference work 14 to a condensing point P2 at a predetermined depth position d2, thereby forming a laser processing region 110 at the condensing point P2.

The depth position d2 is a position shallower than the depth position d1. Further, the depth position d2 is an assumed value of the length of the crack 112 extending from the laser processing region 110 formed inside the reference work 14 by the laser optical system 22a in the normal state toward the front surface 14a side (the depth position d2). It is the position corresponding to the design value). The normal state referred to here is a state in which a change in the position of the optical axis A1 of the laser optical system 22a, a change in the inclination of the optical axis A1, and a change in the state such as uneven light intensity have not occurred. The assumed value of the length of the crack 112, that is, the depth position d2 is predetermined by an experiment or a simulation.

By forming the laser processing region 110 at the depth position d2 of the reference work 14 by the laser optical system 22a, if the laser optical system 22a is in the normal state, the lower side (front surface 12a) in the Z direction from the laser processing region 110 The tip of the crack 112 extending to the side) substantially coincides with the front surface 14a. As a result, the above-mentioned BHC appears on the front surface 14a.

Next, the second laser machining control unit 100 drives the unit drive mechanism 34 via the movement control unit 84 to move the machining unit 22 in the Y direction (corresponding to the parallel direction of the present invention). As a result, the laser optical system 22a is relatively moved in the Y direction with respect to the reference work 14 in a state where the laser beam L is focused on the focusing point P2. As a result, the laser machining region 110 is formed inside the reference work 14 along the Y direction. Further, cracks 112 are generated in the thickness direction (Z direction) of the reference work 14 starting from each laser machining region 110 along the Y direction.

FIG. 8 is a front view of the front surface 14a of the reference work 14 after laser machining. As shown in FIG. 8, when the laser machining region 110 is formed along the Y direction at the internal depth position d2 of the reference work 14 by the laser machining shown in FIG. 7 described above, the laser optical system 22a is normal. In the state, the crack 112 extending from the laser processing region 110 along the Y direction becomes BHC. As a result, as shown by reference numeral 8A in FIG. 8, a crack 112 (BHC) appears substantially linearly on the front surface 14a of the reference work 14 along the Y direction.

On the other hand, when a state change occurs in the laser optical system 22a, the length of the crack 112 extending from the laser processing region 110 formed along the Y direction becomes unstable, or inside the reference work 14. The position of the focusing point P2 (depth position d2) may become unstable.

For example, as shown by reference numeral 8B in FIG. 8, when the length of the crack 112 extending from the laser processing region 110 becomes unstable, the crack 112 (BHC) appears intermittently on the front surface 14a, or mainly. The crack 112 may not appear on the surface 14a. Further, as shown by reference numeral 8C in FIG. 8, when the position of the condensing point P2 becomes unstable due to a change in the position of the condensing lens 62 of the laser optical system 22a or the like, the laser beam L When the light passes through the front surface 14a, a damage mark 113 of the laser beam L may appear on the front surface 14a.

In this way, by setting the Z-direction position of the condensing point P2 when laser machining the reference work 14 to the depth position d2, the front surface 14a of the reference work 14 after the laser machining is set. Based on the state (processing result of laser processing), it is possible to diagnose whether the laser optical system 22a is in a normal state or a state change has occurred.

Returning to FIG. 5, the image acquisition control unit 102 operates after the laser machining on the reference work 14 is completed. The image acquisition control unit 102 controls the BHC photographing system 26 via the photographing control unit 88, and through the sub-table 24, the illumination of the front surface 14a of the reference work 14 by the illumination light source 74 and the front surface by the camera 76. The image of the surface 14a is executed. As a result, the front surface photographed image 78 (image data) of the reference work 14 is acquired by the camera 76, and the front surface photographed image 78 is output from the camera 76 to the image acquisition control unit 102. The front surface photographed image 78 corresponds to crack information indicating a crack 112 (BHC) extending from the laser processing region 110 toward the front surface 14a.

When the front surface image 78 is input from the camera 76, the image acquisition control unit 102 controls the display control unit 90 to perform surface imaging on the monitor 73 (corresponding to the display unit of the present invention). Image 78 is displayed. As a result, the crack information of the reference work 14 is presented to the operator.

[Action of the first embodiment]
FIG. 9 shows the diagnostic processing of the laser optical system 22a by the laser processing apparatus 10 having the above configuration corresponding to the diagnostic method of the present invention, and more specifically, the acquisition and display processing of the front surface photographed image 78 of the reference work 14. It is a flowchart which shows the flow. Since the flow of the laser processing process of the product work 12 by the laser processing device 10 is a known technique, a specific description thereof will be omitted here.

As shown in FIG. 9, the operator starts the diagnostic processing of the laser optical system 22a of the laser processing apparatus 10 at predetermined diagnostic timings, for example, at the time of starting the laser processing apparatus 10 or at regular intervals. First, the operator arranges the reference work 14 on the holding surface 24a of the sub-table 24, and then the operation unit 75 performs a suction operation of the reference work 14. In response to this operation, the suction control unit 82 starts driving the table suction source 30. As a result, the suction source 36 for the sub-table sucks air from each suction groove 24b, so that the front surface 14a of the reference work 14 is sucked and held by the holding surface 24a (step S1, in the holding step of the present invention). Equivalent).

When the reference work 14 is held in the sub-table 24, or when the laser machining start operation of the reference work 14 is input in the operation unit 75, the second laser machining control unit 100 drives the unit via the movement control unit 84. The mechanism 34 is driven to align the sub-table 24 with the optical axis A1 of the laser optical system 22a. As a result, the laser optical system 22a and the reference work 14 are aligned (step S2).

Next, the second laser machining control unit 100 controls the laser optical system 22a to condense the laser beam L to the depth position d2 (condensing point P2) inside the reference work 14, and to this depth position d2. The laser processing region 110 is formed (step S3, corresponding to the laser processing region forming step of the present invention). Further, the second laser machining control unit 100 drives the unit drive mechanism 34 via the movement control unit 84 to move the machining unit 22 in the Y direction (step S4, corresponding to the relative movement step of the present invention). As a result, the laser machining region 110 is formed at the depth position d2 in the reference work 14 along the Y direction, and the crack 112 extending from the laser machining region 110 in the Z direction (vertical direction) is formed.

After the laser machining of the reference work 14 is completed, the image acquisition control unit 102 controls the BHC imaging system 26 via the imaging control unit 88 to illuminate and photograph the front surface 14a of the reference work 14 through the subtable 24. (Step S5, corresponding to the captured image acquisition step of the present invention). As a result, the front surface photographed image 78 is output from the BHC photographing system 26 to the image acquisition control unit 102.

The image acquisition control unit 102 that has acquired the front surface photographed image 78 displays the front surface photographed image 78 on the monitor 73 (step S6). Then, the operator starts the diagnosis of the laser optical system 22a by confirming the front surface photographed image 78 (crack information of the reference work 14) displayed on the monitor 73.

When the BHC appears substantially linearly along the Y direction on the front surface 14a of the reference work 14, the operator sets the laser optical system 22a as shown by reference numeral 8A in FIG. Diagnose as normal. On the contrary, BHC appears intermittently on the front surface 14a as shown by reference numeral 8B in FIG. 8, or laser light is emitted on the front surface 14a as shown by reference numeral 8C in FIG. When the damage mark 113 of L appears, the operator determines that the state change of the laser optical system 22a has occurred, and adjusts or replaces the laser optical system 22a.

In the present embodiment, the operator diagnoses the laser optical system 22a based on the front surface photographed image 78, but the image analysis process [AI (artificial intelligence) image analysis of the front surface photographed image 78 is performed. Including] may automatically perform the diagnosis of the laser optical system 22a.

Hereinafter, the processes of steps S1 to S6 described above are repeatedly executed at each diagnosis timing, and the operator's diagnosis based on the front surface photographed image 78 is executed.

[Effect of the first embodiment]
As described above, in the laser processing apparatus 10 of the first embodiment, the laser processing region 110 is formed at the depth position d2 of the reference work 14 by laser processing, and the front surface photographed image 78 of the reference work 14 is passed through the subtable 24. By acquiring the above, it is possible to diagnose whether or not a state change of the laser optical system 22a has occurred without going through the next step of laser machining (application of an external pressure by cutting or the like). As a result, it is possible to easily diagnose whether or not a state change of the laser optical system 22a has occurred, so that it is possible to prevent a large amount of defective products from being generated by laser processing.

[Second Embodiment]
FIG. 10 is a schematic view of the laser processing apparatus 10 of the second embodiment. In FIG. 10, the chuck table 20 is not shown.

In the first embodiment, the front surface 14a of the reference work 14 is photographed through the subtable 24 by the BHC photographing system 26 arranged on the lower side in the Z direction of the subtable 24, but in the second embodiment, processing is performed. The front surface 14a is photographed using the infrared microscope 22b of the unit 22.

As shown in FIG. 10, the laser processing apparatus 10 of the second embodiment is the same as the laser processing apparatus 10 of the first embodiment except that the illumination light source 118 and the relay optical system 120 are provided instead of the BHC photographing system 26. It has basically the same configuration. Therefore, those having the same function or configuration as the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The illumination light source 118 is arranged on the lower side in the Z direction of the sub-table 24, and irradiates the illumination light toward the front surface 14a of the reference work 14 through the half mirror 124 and the sub-table 24 described later. This illumination light is light in the wavelength range of infrared light (near infrared light) corresponding to photography by the infrared camera 70 of the infrared microscope 22b. Reference numeral A4 in the drawing is an illumination axis of the illumination light source 118.

The relay optical system 120 guides the image (image light) of the front surface 14a of the reference work 14 to a position where it can be photographed by the infrared microscope 22b. Reference numeral A5 in the figure is an optical axis of the relay optical system 120. The relay optical system 120 includes a half mirror 124, a screen 126, a relay lens 128, a mirror 130, and an imaging lens 132.

The half mirror 124 is arranged between the sub-table 24 and the illumination light source 118. The half mirror 124 transmits a part of the illumination light incident from the illumination light source 118 and emits the illumination light toward the sub-table 24. As a result, the illumination light passes through the sub-table 24 and is incident on the reference work 14, and a part of the illumination light reflected by the front surface 14a of the reference work 14 is incident on the half mirror 124 as reflected light. The half mirror 124 reflects the reflected light incident from the sub-table 24 toward the relay lens 128.

The screen 126 has an XY surface at a position on the side of the sub-table 24 in the X direction and at a position overlapping a part of the moving range of the infrared microscope 22b in the Y direction when viewed from the Z direction (upper side). It is arranged parallel to. That is, the screen 126 is provided at a position that does not hinder the movement of the chuck table 20 in the X direction and at a position where the image can be taken by the infrared microscope 22b. Further, the position of the screen 126 in the Z direction is adjusted so as to coincide with the position of the holding surface 24a of the subtable 24 in the Z direction.

The relay lens 128 is arranged at a position on the side of the half mirror 124 in the X direction. The relay lens 128 emits the reflected light reflected by the half mirror 124 toward the mirror 130.

The mirror 130 is arranged at a position on the side of the relay lens 128 in the X direction and at a position on the lower side of the screen 126 in the Z direction. The mirror 130 reflects the reflected light incident from the relay lens 128 toward the imaging lens 132 located on the upper side in the Z direction.

The imaging lens 132 is arranged between the screen 126 and the mirror 130. The imaging lens 132 forms an image of the reflected light reflected by the mirror 130 on the screen 126. As a result, the image of the front surface 14a of the reference work 14 is projected on the screen 126 through the half mirror 124, the relay lens 128, the mirror 130, and the imaging lens 132.

The table drive mechanism 32 and the unit drive mechanism 34 of the second embodiment also function as the second relative movement mechanism of the present invention. Under the control of the control device 28, the table drive mechanism 32 and the unit drive mechanism 34 use the infrared microscope 22b for the product work 12 and the relay optical system 120, and the imaging position and screen 126 (on the screen 126) for photographing the product work 12. The projected image of the front surface 14a) is moved relative to the shooting position to be shot.

Specifically, the alignment detection unit 96 of the second embodiment drives the table drive mechanism 32 and the unit drive mechanism 34 in the same manner as in the first embodiment before the laser machining of the product work 12, and displays the infrared microscope 22b. The alignment reference of the product work 12 is relatively moved to a shooting position where shooting is possible. This enables the alignment detection described above.

The image acquisition control unit 102 of the second embodiment can drive the unit drive mechanism 34 after the laser machining on the reference work 14 is completed to photograph the infrared microscope 22b and the screen 126 (the image of the front surface 14a). Move relative to the shooting position. Next, the image acquisition control unit 102 controls the infrared microscope 22b via the imaging control unit 88 to execute the imaging of the screen 126 by the infrared camera 70. As a result, the front surface photographed image 78 is acquired by the infrared camera 70.

As described above, in the second embodiment, by providing the relay optical system 120, the front surface 14a of the reference work 14 can be photographed by the infrared microscope 22b via the relay optical system 120. As a result, the front surface photographed image 78 can be acquired using the infrared microscope 22b for alignment detection, so that the camera 76 of the first embodiment can be omitted, and the cost of the laser processing apparatus 10 can be reduced. Can be planned.

In the second embodiment, the front surface 14a of the reference work 14 is photographed by the infrared microscope 22b via the relay optical system 120. For example, the BHC photographing system 26 (camera 76) is attached to the sub-table 24. The front surface 14a can be photographed even when the front surface 14a is arranged at a position different from the position facing the lower surface 24c. That is, by changing the configuration of the relay optical system 120, it is possible to acquire the front surface photographed image 78 regardless of the position and orientation of various photographing systems (cameras) such as the BHC photographing system 26. As a result, the degree of freedom in designing the laser processing apparatus 10 can be increased.

[Third Embodiment]
FIG. 11 is a schematic view of the laser processing apparatus 10 of the third embodiment. In each of the above embodiments, the chuck table 20 and the sub table 24 are separately provided, but as shown in FIG. 11, in the third embodiment, the chuck table 20 and the sub table 24 are integrated. ..

As shown in FIG. 11, the laser machining apparatus 10 of the third embodiment has basically the same configuration as the laser machining apparatus 10 of each of the above embodiments except that the chuck table 20 is provided with the table holding portion 138. Is. Therefore, those having the same function or configuration as each of the above embodiments are designated by the same reference numerals and the description thereof will be omitted.

The table holding unit 138 holds the sub-table 24. As a result, the sub-table 24 is fixed to the chuck table 20 via the table holding portion 138, and the sub-table 24 moves integrally with the chuck table 20. As a result, by driving the table drive mechanism 32 and the unit drive mechanism 34, the laser optical system 22a and the BHC photographing system 26 can move relative to the sub-table 24 (reference work 14).

In the third embodiment as well, by providing the relay optical system 120 as in the second embodiment shown in FIG. 11 described above, the reference work 14 is provided by the infrared microscope 22b via the relay optical system 120. The front surface 14a may be photographed.

[Other]
In each of the above embodiments, the table drive mechanism 32 and the unit drive mechanism 34 have been described as examples from the first relative movement mechanism to the third relative movement mechanism of the present invention, but the chuck table 20 and the sub table 24 have been described. The configuration is not particularly limited as long as the laser optical system 22a can be relatively moved or the BHC photographing system 26 (infrared microscope 22b) can be relatively moved.

In each of the above embodiments, the infrared microscope 22b is connected to the outside of the laser optical system 22a, but the infrared microscope 22b may be provided inside the housing of the laser optical system 22a.

In each of the above embodiments, the reference work 14 and the laser optical system 22a are relatively moved in the X direction during laser machining with respect to the reference work 14, but this relative movement does not have to be performed. In this case, based on the front surface photographed image 78, the presence or absence of a state change of the laser optical system 22a can be easily diagnosed depending on the presence or absence of BHC and the presence or absence of damage marks 113.

In each of the above embodiments, the laser machining region 110 is formed at the depth position d2 during laser machining with respect to the reference work 14, but if the presence / absence of BHC and the presence / absence of damage marks 113 can be observed, the depth position d2 The laser processing region 110 may be formed at a deeper position or a shallow position.

10 ... Laser processing device 12 ... Product work 14 ... Reference work 14a ... Front surface 14b ... Back surface 20 ... Chuck table 22 ... Processing unit 22a ... Laser optical system 22b ... Infrared microscope 24 ... Sub table 24a ... Holding surface 24c ... Bottom surface 26 ... BHC imaging system 28 ... Control device 32 ... Table drive mechanism 34 ... Unit drive mechanism 40 ... Laser light source 64 ... Illumination light source 70 ... Infrared camera 71 ... Infrared photographed image 72 ... Microscope 74 ... Illumination light source 76 ... Camera 78 ... Mainly Surface captured image 80 ... Integrated control unit 84 ... Movement control unit 86 ... Laser control unit 88 ... Imaging control unit 90 ... Display control unit 96 ... Alignment detection unit 98 ... First laser processing control unit 100 ... Second laser processing control unit 102 ... Image acquisition control unit 110 ... Laser processing area 112 ... Crack 118 ... Illumination light source 120 ... Relay optical system 138 ... Table holding units d1, d2 ... Depth position

Claims (13)

A light-transmitting reference work holding table having a holding surface for holding a reference work manufactured under predetermined manufacturing conditions,
A laser optical system that irradiates a laser beam toward the reference work and condenses the laser light inside the reference work to form a laser processing region inside the reference work.
By acquiring a photographed image of the contact surface of the reference work that abuts on the holding surface through the reference work holding table, the crack information of a crack extending from the laser processing region toward the contact surface is acquired. Image acquisition department and
Laser processing equipment equipped with. The laser optical system forms the laser machining region at a predetermined depth position from the contact surface in the thickness direction of the reference work and at a depth position corresponding to an assumed value of the crack length. The laser processing apparatus according to claim 1. The laser processing apparatus according to claim 1 or 2, wherein the reference work holding table is a sub-table different from the product work holding table that holds the product work. The laser processing apparatus according to claim 3, wherein the reference work holding table is held in the product work holding table. While the laser beam is being irradiated from the laser optical system toward the reference work, the laser optical system is moved relative to the reference work, and the reference work is moved along a direction parallel to the reference work. The laser processing apparatus according to any one of claims 1 to 4, further comprising a first relative movement mechanism for forming the laser processing region inside the laser processing apparatus. Equipped with a product work holding table to hold the product work
The first relative movement mechanism moves the laser optical system relative to the reference work holding table and the product work holding table to a position facing the reference work and a position facing the product work.
When the laser optical system is relatively moved to a position facing the product work by the first relative movement mechanism, the laser light is irradiated toward the product work and the laser light is emitted to the inside of the product work. The laser processing region is formed inside the product work by condensing the light on the product.
While the first relative moving mechanism irradiates the laser beam from the laser optical system toward the product work, the first relative moving mechanism moves the laser optical system relative to the product work and is parallel to the product work. The laser processing apparatus according to claim 5, wherein the laser processing region is formed inside the product work along the same direction. Claim 1 is a camera in which the captured image acquisition unit is arranged at a position facing another surface of the reference work holding table opposite to the holding surface, and the contact surface is photographed through the reference work holding table. 6. The laser processing apparatus according to any one of 6. The captured image acquisition unit
When the surface of the reference work holding table opposite to the holding surface is the other surface, the camera is arranged at a position different from the position facing the other surface.
A relay optical system that guides an image of the contact surface from a position facing the other surface to a position that can be photographed by the camera.
The laser processing apparatus according to any one of claims 1 to 6. The camera is arranged above the reference work holding table.
The product work holding table that holds the product work and the product work holding table
A second relative that moves the camera relative to the product work and the relay optical system to a shooting position where the product work is photographed and an image of the contact surface guided by the relay optical system. Movement mechanism and
The laser processing apparatus according to claim 8. The laser processing apparatus according to any one of claims 1 to 9, further comprising a display unit for displaying the photographed image acquired by the photographed image acquisition unit. A holding step in which a reference work manufactured under predetermined manufacturing conditions is held on the holding surface of the light-transmitting reference work holding table, and a holding step.
A laser processing region forming step of irradiating a laser beam from a laser optical system toward the reference work and condensing the laser light inside the reference work to form a laser processing region inside the reference work.
By acquiring a photographed image of the contact surface of the reference work that abuts on the holding surface through the reference work holding table, the crack information of a crack extending from the laser processing region toward the contact surface is acquired. Image acquisition step and
A method of diagnosing a laser processing apparatus having. In the laser machining region forming step, the laser machining region is located at a predetermined depth position from the contact surface in the thickness direction of the reference work and at a depth position corresponding to an assumed value of the crack length. The method for diagnosing a laser processing apparatus according to claim 11. While the laser beam is being irradiated from the laser optical system toward the reference work, the laser optical system is moved relative to the reference work, and the reference work is moved along a direction parallel to the reference work. The method for diagnosing a laser processing apparatus according to claim 11 or 12, further comprising a relative moving step for forming the laser processing region inside the laser processing apparatus.

Images