JP2022069032A - Laser processing device - Google Patents

Abstract

To provide a laser processing device which detects contamination risk of an optical component in advance, and can previously prevent troubles.SOLUTION: A laser processing device comprises a chuck table for holding a work-piece, a laser oscillator, a condenser for condensing laser beam 21 oscillated from the laser oscillator, and an optical component for guiding the laser beam 21 to the condenser from the laser oscillator, and has a light detection unit 26 located at a position where the same can receive light 213 generated by particles 212 existing in a light path 211 of the laser beam 21. The device condenses the laser beam 21 oscillated from the laser oscillator and irradiates the work-piece with the same, and simultaneously, can detect the particles 212 existing in the light path 211 of the laser beam 21 on the basis of a reception amount of the light 213 generated by the particles 212 that have been received by the light detection unit 26.SELECTED DRAWING: Figure 3

Description

The present invention relates to a laser processing apparatus.

In order to chip a workpiece such as a semiconductor wafer, a laser processing apparatus that irradiates a laser beam along a street set on the surface of the workpiece is used (see, for example, Patent Document 1).

Such a laser processing device is equipped with a laser oscillator, and the laser beam oscillated from this laser oscillator is guided to a condenser lens using a plurality of optical components, and the workpiece is focused and irradiated for processing. It is carried out.

Japanese Patent Application Laid-Open No. 2003-320466

If particles or the like adhere to and contaminate the optical components used in the laser processing apparatus shown in Patent Document 1 and the like, the output is directly reduced at the processing point and the shape of the laser beam is distorted. Therefore, the laser processing device arranges these optical components inside a box isolated from the outside.

However, the laser processing apparatus shown in Patent Document 1 and the like cannot block particles generated from parts arranged inside the box and particles entering the inside of the box through a slight gap, and the box cannot be blocked. Although the troubles have been reduced by increasing the degree of sealing and eliminating contaminants, there was a problem that it could not be found until the problem actually occurred.

The present invention has been made in view of the above facts, and an object of the present invention is to provide a laser processing apparatus capable of detecting the risk of contamination of optical components in advance and preventing troubles in advance.

In order to solve the above-mentioned problems and achieve the object, the laser processing apparatus of the present invention uses a chuck table having a holding surface for holding a workpiece, a laser oscillator, and a laser beam oscillated from the laser oscillator. A work piece held on the chuck table and a light-collecting point of the laser beam are provided with a light-collecting condenser and an optical component that guides the laser beam from the laser oscillator to the light-collecting condenser. It is a laser processing device that processes a work piece by moving it relatively, and has a light detection unit arranged at a position where it can receive light generated by particles existing in the optical path of the laser beam. Then, the laser beam oscillated from the laser oscillator is focused and irradiated on the work piece to process the work piece, and the optical path of the laser beam is based on the amount of light received by the particles received by the light detection unit. It is characterized by being able to detect particles existing inside.

The present invention has an effect that it is possible to detect the risk of contamination of optical components in advance and prevent troubles in advance.

FIG. 1 is a perspective view showing a configuration example of the laser processing apparatus according to the first embodiment. FIG. 2 is an explanatory diagram illustrating a schematic configuration of a laser beam irradiation unit of the laser processing apparatus shown in FIG. 1. FIG. 3 is a diagram schematically showing a state in which the photodetector unit receives light generated by particles during laser processing of the laser processing apparatus shown in FIG. 1. FIG. 4 is a diagram showing an example of the amount of light received by the photodetector unit shown in FIG. FIG. 5 is a diagram showing information stored in the storage unit by the control unit of the laser processing apparatus according to the modified example of the first embodiment.

An embodiment (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Further, various omissions, substitutions or changes of the configuration can be made without departing from the gist of the present invention.

[Embodiment 1]
The laser processing apparatus according to the first embodiment of the present invention will be described with reference to the drawings. First, the configuration of the laser processing apparatus 1 according to the first embodiment will be described. FIG. 1 is a perspective view showing a configuration example of the laser processing apparatus according to the first embodiment. The laser processing apparatus 1 shown in FIG. 1 according to the first embodiment is an apparatus that irradiates a work piece 200 with a pulsed laser beam 21 and performs laser processing (corresponding to processing) on the work piece 200. be.

(Workpiece)
The workpiece 200 to be machined by the laser machining apparatus 1 shown in FIG. 1 is a disk-shaped semiconductor wafer or an optical device wafer or the like having a substrate 201 such as silicon, sapphire, or gallium arsenide. In the workpiece 200, a plurality of streets 203 intersecting the surface 202 of the substrate 201 are set, and the device 204 is formed in the area partitioned by the street 203.

The device 204 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

Further, in the first embodiment, the workpiece 200 has a disk shape having a diameter larger than the outer diameter of the workpiece 200, and an adhesive tape 208 having an annular frame 207 attached to the outer edge portion is attached to the back surface 205. It is worn and supported within the opening 209 of the frame 207.

In the first embodiment, the workpiece 200 is individually laser-processed along the street 203 while being supported in the opening 209 of the frame 207 by the adhesive tape 208 and laser-processed by the laser processing device 1. It is divided into device chips 206. The device chip 206 includes a part of the substrate 201 and the device 204.

(Laser processing equipment)
The laser processing apparatus 1 is an apparatus that irradiates the workpiece 200 with a laser beam 21 along the street 203 to perform laser processing on the workpiece 200. As shown in FIG. 1, the laser processing apparatus 1 includes a chuck table 10 having a holding surface 11 for holding a workpiece 200, a laser beam irradiation unit 20, a moving unit 30, an imaging unit 40, and a control unit 100. And prepare.

The chuck table 10 holds the workpiece 200 on a holding surface 11 parallel to the horizontal direction. The holding surface 11 has a disk shape formed of porous ceramic or the like, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown). The chuck table 10 sucks and holds the workpiece 200 placed on the holding surface 11. A plurality of clamp portions 12 for sandwiching the frame 207 that supports the workpiece 200 in the opening 209 are arranged around the chuck table 10.

Further, the chuck table 10 is rotated by the rotational movement unit 34 of the moving unit 30 about an axial center orthogonal to the holding surface 11 and parallel to the Z-axis direction parallel to the vertical direction. The chuck table 10 is moved in the X-axis direction parallel to the horizontal direction by the X-axis moving unit 31 of the moving unit 30 together with the rotary moving unit 34, and is parallel to the horizontal direction and orthogonal to the X-axis direction by the Y-axis moving unit 32. It is moved in the Y-axis direction. The chuck table 10 is moved by the moving unit 30 over a processing region below the laser beam irradiation unit 20 and a loading / unloading region where the workpiece 200 is carried in and out away from below the laser beam irradiation unit 20. Laser.

The laser beam irradiation unit 20 is a unit that irradiates the workpiece 200 held on the chuck table 10 with a pulsed laser beam 21. In the first embodiment, the laser beam irradiation unit 20 irradiates the workpiece 200 with a pulsed laser beam 21 having a wavelength that is absorbent or has a wavelength that is transparent to the workpiece 200. This is a laser beam irradiation means for performing laser processing on the work piece 200.

In the first embodiment, as shown in FIG. 1, a part of the laser beam irradiation unit 20 is in the Z-axis direction by the Z-axis moving unit 33 of the moving unit 30 provided on the erection wall 3 erected from the apparatus main body 2. It is supported by the elevating member 4 that is moved to.

Next, the configuration of the laser beam irradiation unit 20 will be described. FIG. 2 is an explanatory diagram illustrating a schematic configuration of a laser beam irradiation unit of the laser processing apparatus shown in FIG. 1. As shown in FIG. 2, the laser beam irradiation unit 20 includes an optical component housing box 22, a laser oscillator 23 that oscillates a pulsed laser beam 21 for processing a workpiece 200, and a holding surface of a chuck table 10. On the optical path 211 of the concentrator 24 that condenses the laser beam 21 oscillated from the laser oscillator 23 on the workpiece 200 held by the laser oscillator 23, and the laser beam 21 between the laser oscillator 23 and the concentrator 24. It includes at least one optical component 25 and a light detection unit 26 that guide the laser beam 21 provided and oscillated by the laser oscillator 23 from the laser oscillator 23 to the condenser 24.

The condenser 24 includes a condenser lens 28 arranged at a position facing the holding surface 11 of the chuck table 10 in the Z-axis direction. The condensing lens 28 transmits the laser beam 21 oscillated from the laser oscillator 23 and condenses the laser beam 21 at the condensing point 21-1. In the first embodiment, the laser beam irradiation unit 20 includes a plurality of mirrors that reflect the laser beam 21 as the optical component 25, but in the present invention, the optical component 25 is not limited to the mirror.

The optical component housing box 22 is formed in a box shape with the inside sealed. In the first embodiment, the optical component housing box 22 houses the optical component 25 and the photodetection unit 26.

The photodetection unit 26 is arranged at a position where light 213 generated by the particles 212 existing in the optical path 211 of the laser beam 21 of the optical component housing box 22 can be received. The photodetection unit 26 receives the light 213 generated by the particles 212 through the lens 27. In the first embodiment, the light detection unit 26 has at least one of scattered light generated by scattering the laser beam 21 by the particles 212 and fluorescence emitted by the particles 212 by the laser beam 21 as the light 213 generated by the particles 212. Receives light.

In the first embodiment, the photodetection unit 26 is a photodiode that outputs a voltage value that changes depending on the amount of light received by the light 213 generated by the received particles 212 to the control unit 100, but the present invention is not limited to the photodiode. In addition, for example, an image pickup unit provided with an image pickup element such as a CCD (Charge Coupled Device) image pickup element or a CMOS (Complementary MOS) image pickup element may be used. The voltage value output by the photodetector unit 26 increases as the amount of light received by the particles 212 increases, and decreases as the amount of light received decreases.

The moving unit 30 relatively moves the laser beam irradiation unit 20 and the chuck table 10 around an axis parallel to the X-axis direction, the Y-axis direction, the Z-axis direction, and the Z-axis direction. The X-axis direction and the Y-axis direction are parallel to the holding surface 11. The moving unit 30 includes an X-axis moving unit 31 which is a machining feed unit that moves the chuck table 10 in the X-axis direction, a Y-axis moving unit 32 which is an indexing feed unit that moves the chuck table 10 in the Y-axis direction, and a laser. It includes a Z-axis moving unit 33 that moves the condenser 24 included in the beam irradiation unit 20 in the Z-axis direction, and a rotational moving unit 34 that rotates the chuck table 10 around an axis parallel to the Z-axis direction.

The Y-axis moving unit 32 is a unit that relatively indexes and feeds the chuck table 10 and the laser beam irradiation unit 20. In the first embodiment, the Y-axis moving unit 32 is installed on the apparatus main body 2 of the laser processing apparatus 1. The Y-axis moving unit 32 supports the moving plate 15 that supports the X-axis moving unit 31 so as to be movable in the Y-axis direction.

The X-axis moving unit 31 is a unit that relatively processes and feeds the chuck table 10 and the laser beam irradiation unit 20. The X-axis moving unit 31 is installed on the moving plate 15. The X-axis moving unit 31 movably supports a second moving plate 16 that supports a rotational moving unit 34 that rotates the chuck table 10 around an axis parallel to the Z-axis direction. The Z-axis moving unit 33 is installed on the upright wall 3 and supports the elevating member 4 so as to be movable in the Z-axis direction.

The X-axis moving unit 31, the Y-axis moving unit 32, and the Z-axis moving unit 33 include a well-known ball screw rotatably provided around the axis, a well-known pulse motor for rotating the ball screw around the axis, and a moving plate. It is provided with a well-known guide rail that movably supports 15 and 16 in the X-axis direction or the Y-axis direction and supports the elevating member 4 movably in the Z-axis direction.

Further, the laser processing apparatus 1 includes an X-axis direction position detection unit (not shown) for detecting the position of the chuck table 10 in the X-axis direction, and a Y-axis (not shown) for detecting the position of the chuck table 10 in the Y-axis direction. It includes a direction position detection unit and a Z-axis direction position detection unit that detects the position of the condenser 24 included in the laser beam irradiation unit 20 in the Z-axis direction. Each position detection unit outputs the detection result to the control unit 100.

The image pickup unit 40 takes an image of the workpiece 200 held on the chuck table 10. The image pickup unit 40 includes an image pickup element such as a CCD (Charge Coupled Device) image pickup element or a CMOS (Complementary MOS) image pickup element that images an image of the workpiece 200 held on the chuck table 10. In the first embodiment, the image pickup unit 40 is attached to the tip of the housing of the laser beam irradiation unit 20 and is arranged at a position aligned with the condenser lens 28 of the condenser 24 of the laser beam irradiation unit 20 in the X-axis direction. ing. The image pickup unit 40 takes an image of the work piece 200, obtains an image for performing alignment for aligning the work piece 200 and the laser beam irradiation unit 20, and outputs the obtained image to the control unit 100. do.

The control unit 100 controls each of the above-mentioned components of the laser machining apparatus 1 to cause the laser machining apparatus 1 to perform a laser machining operation on the workpiece 200. The control unit 100 is an arithmetic processing unit having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a ROM (read only memory) or a RAM (random access memory), and input / output. It is a computer having an interface device. The arithmetic processing device of the control unit 100 performs arithmetic processing according to a computer program stored in the storage device, and transmits a control signal for controlling the laser processing apparatus 1 to the laser processing apparatus 1 via an input / output interface apparatus. The function of the control unit 100 is realized by outputting to the above-mentioned components.

Further, the control unit 100 is connected to a display unit 110 composed of a liquid crystal display device or the like for displaying a processing operation state, an image, or the like, and an input unit (not shown) used when an operator registers processing content information or the like. ing. The input unit is composed of at least one of a touch panel provided on the display unit 110 and an external input device such as a keyboard. Further, the control unit 100 includes a storage unit 101 capable of storing information. The function of the storage unit 101 is realized by the above-mentioned storage device.

Next, the processing operation of the laser processing apparatus 1 described above will be described. FIG. 3 is a diagram schematically showing a state in which the photodetector unit receives light generated by particles during laser processing of the laser processing apparatus shown in FIG. 1. FIG. 4 is a diagram showing an example of the amount of light received by the photodetector unit shown in FIG.

In the laser machining apparatus 1 having the above-described configuration, the control unit 100 receives the machining conditions input by the operator by operating the input unit and the like, and the holding surface 11 of the chuck table 10 is positioned in the loading / unloading region via the adhesive tape 208. The workpiece 200 is placed on the machine. The processing conditions include the output of the laser beam 21, the repetition frequency, the moving speed of the chuck table 10 in the X-axis direction, which is the processing feed speed, the position of the condensing point 21-1 in the Z-axis direction, and the like.

In the first embodiment, the laser machining apparatus 1 starts the machining operation when the control unit 100 receives the operator's machining operation start instruction from the input unit. When the machining operation is started, the laser machining apparatus 1 sucks and holds the workpiece 200 on the holding surface 11 of the chuck table 10 via the adhesive tape 208, and clamps the frame 207 with the clamping portion 12.

In the first embodiment, in the laser machining apparatus 1, the moving unit 30 moves the chuck table 10 toward the machining region, and the imaging unit 40 photographs the workpiece 200. The laser processing device 1 performs alignment based on the image obtained by the image pickup unit 40.

In the first embodiment, the laser processing apparatus 1 has a work piece 200 in which the moving unit 30 is held on the chuck table 10 and a condensing point 21 of the laser beam 21 irradiated by the laser beam irradiation unit 20 based on the processing conditions. The laser beam irradiation unit 20 irradiates the street 203 with a pulsed laser beam 21 while moving -1 and -1 relatively along the street 203, thereby performing laser processing on the workpiece 200.

In the first embodiment, the laser processing apparatus 1 focuses the laser beam 21 oscillated from the laser oscillator 23 at a position in the Z-axis direction determined by the processing conditions of the workpiece 200, and causes the laser beam 21 to be focused on the workpiece 200. The 200 is irradiated (that is, focused and irradiated), and the workpiece 200 is laser-processed. Further, in the first embodiment, the laser processing apparatus 1 performs laser processing on the workpiece 200, and the light detection unit 26 is inside the optical component storage box 22 of the laser beam irradiation unit 20 as shown in FIG. It receives the light 213 generated by the particles 212. The photodetection unit 26 outputs a voltage value corresponding to the amount of received light received by the light 213 to the control unit 100.

In the first embodiment, in the laser processing apparatus 1, the control unit 100 exceeds the predetermined threshold value 300 shown in FIG. 4 in the voltage value corresponding to the amount of received light of the light 213 from the photodetection unit 26. The storage unit 101 stores information 102 in which the number of times and the voltage value when the voltage exceeds the value are associated with each other on a one-to-one basis. The number of times the voltage value exceeds the threshold value 300 corresponds to the number of particles 212 in the optical component accommodating box 22, and the voltage value when the voltage value exceeds the threshold value corresponds to the particle size of the particles 212. In the first embodiment, the threshold value 300 is a value that may cause trouble when the laser processing apparatus 1 performs laser processing.

In this way, in the laser processing apparatus 1, the number of times the voltage value corresponding to the amount of received light from the light detection unit 26 of the light 213 exceeds the predetermined threshold value 300 shown in FIG. 4, and the voltage value exceeded. By storing the information 102 having a one-to-one correspondence with each other in the storage unit 101, the storage unit 101 stores the number of particles 212 in the optical component accommodating box 22 and the information corresponding to the particle size of the particles 212. It becomes. Further, the laser processing apparatus 1 is present in the optical path 211 of the laser beam 21 based on the amount of light received by the light 213 generated by the particles 212 received by the light detection unit 26 by storing the above-mentioned information 102 in the storage unit 101. It is possible to detect the particles 212 to be generated. The horizontal axis of FIG. 4 shows the elapsed time from the start of the machining operation, and the vertical axis of FIG. 4 shows the voltage value from the photodetection unit 26.

In the first embodiment, when the laser processing apparatus 1 irradiates all the streets 203 of the workpiece 200 with the laser beam 21, the irradiation of the laser beam 21 is stopped. In the first embodiment, in the laser processing apparatus 1, the moving unit 30 moves the chuck table 10 toward the loading / unloading region, the chuck table 10 is stopped at the loading / unloading region, and the chuck table 10 holds the suction of the workpiece 200. At the same time as stopping, the clamp portion 12 releases the clamp of the frame 207, the workpiece 200 is carried out from the holding surface 11 of the chuck table 10, and the machining operation is completed.

As described above, the laser processing apparatus 1 according to the first embodiment includes a photodetection unit 26 arranged at a position where light 213 generated by particles 212 existing in the optical path 211 of the laser beam 21 can be received. ing. Therefore, the laser processing apparatus 1 can detect the particles 212 in the optical path 211 which can be a pollution source of the optical component 25 by receiving the light 213 generated by the particles 212 in the photodetection unit 26. As a result, the laser processing apparatus 1 can detect the risk of contamination of the optical component 25 in advance and prevent the occurrence of troubles such as processing defects.

Further, since the laser processing apparatus 1 according to the first embodiment stores the above-mentioned information 102 in the storage unit 101 during laser processing of the workpiece 200, the number of particles 212 that may cause troubles in the optical path 211. And the particle size of the particles 212 can be grasped during laser processing.

[Modification example]
A laser processing apparatus according to a modified example of the first embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a diagram showing information stored in the storage unit by the control unit of the laser processing apparatus according to the modified example of the first embodiment. The laser machining apparatus 1 according to the modified example is the same as that of the first embodiment except that the information 102-1 stored in the storage unit 101 is different during the machining operation.

The information 102-1 stored in the storage unit 101 by the control unit 100 of the laser processing apparatus 1 according to the modification shown in FIG. 5 is when the voltage value from the photodetection unit 26 exceeds the threshold value 300 (that is,). , When the particle 212 is detected), the processing conditions and the time are associated with each other on a one-to-one basis.

In the laser processing apparatus 1 according to the modified example, the control unit 100 stores in the storage unit 101 information 102-1 in which the voltage value when the threshold value exceeds 300, the processing conditions, and the time are associated with each other on a one-to-one basis. Therefore, by analyzing the information 102-1 stored in the storage unit 101, it becomes possible to analyze the generation tendency of the particles 212, and it becomes easy to investigate the cause of the generation of the particles 212.

The present invention is not limited to the above embodiment. That is, it can be variously modified and carried out within a range that does not deviate from the gist of the present invention. For example, in the present invention, the laser machining apparatus 1 may issue an error and interrupt the machining operation without storing the information 102 and 102-1 when the threshold value 300 is exceeded. In this case, the laser machining apparatus 1 can promptly make the operator recognize the generation of the particles 212 during the machining operation. Also. In the present invention, various filters (ultraviolet rays filters) that transmit light 213 may be arranged between the photodetection unit 26 and the lens 27, and the light 213 may be received by the photodetection unit 26.

1 Laser Machining Equipment 10 Chuck Table 11 Holding Surface 21 Laser Beam 23 Laser Oscillator 24 Condenser 26 Light Detection Unit 200 Work Material 211 Optical Path 212 Particles 213 Light

Claims (1)

A chuck table with a holding surface for holding the work piece,
With a laser oscillator,
A condenser that collects the laser beam oscillated from the laser oscillator, and
It comprises an optical component that guides the laser beam from the laser oscillator to the condenser.
A laser processing device that processes a work piece by relatively moving the work piece held on the chuck table and the condensing point of the laser beam.
It has a photodetection unit arranged at a position where it can receive light generated by particles existing in the optical path of the laser beam.
While processing the work piece by condensing and irradiating the work piece with the laser beam oscillated from the laser oscillator, the laser beam is placed in the optical path of the laser beam based on the amount of light received by the particles received by the light detection unit. A laser processing device that can detect existing particles.

Images