Laser processing equipment

Abstract

The present invention provides a laser processing device that can monitor the output of a laser beam during processing without interrupting the processing while processing a workpiece. The laser beam irradiation unit of the laser processing device includes: a laser oscillator; a reflector that reflects the laser beam emitted from the laser oscillator and propagates it to a processing point; an output measurement unit that measures the output of leakage light of the laser beam that is not reflected by the reflector but passes through; and a focusing lens that converges the laser beam propagated through the reflector and irradiates the workpiece. The control unit measures the output of the leakage light of the laser beam using the output measurement unit while irradiating the workpiece with the laser beam.

Description

Technical Field

[0001] The invention relates to a laser processing device. Background Art

[0002] As methods for processing a workpiece such as a semiconductor wafer, there are known methods of irradiating a laser beam with an absorptive wavelength onto the front surface of the workpiece to form a processing groove and a method of converging a laser beam with a wavelength that is transparent to the workpiece and irradiating the interior of the workpiece to form a modified layer serving as a starting point for division (see patent documents 1 and 2).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2003-320466

[0004] Patent Document 2: Japanese Patent Application Publication No. 2002-192370

[0005] Regarding the laser processing device that performs the above-mentioned laser processing, there is an increasing need to suppress the poor segmentation of the workpiece by monitoring the change in the output of the laser beam during processing. As a method for measuring the output of the laser beam, there are a method of blocking the light path using an output measurement unit and a method of interrupting the processing and irradiating the output measurement unit with a laser beam. However, these methods require interrupting the processing, and it is difficult to measure the output while processing the workpiece. Summary of the invention

[0006] Therefore, an object of the present invention is to provide a laser processing apparatus capable of monitoring the output of a laser beam during processing without interrupting the processing while processing a workpiece.

[0007] According to the present invention, a laser processing device is provided, wherein the laser processing device comprises: a chuck table that holds a workpiece; a laser beam irradiation unit that irradiates a pulsed laser beam to the workpiece held by the chuck table; a processing feed unit that performs processing feed on the chuck table and the laser beam irradiation unit relative to each other; a graduation feed unit that performs graduation feed on the chuck table and the laser beam irradiation unit relative to each other; and a control unit, wherein the laser beam irradiation unit comprises: a laser oscillator; a reflection mirror that reflects the laser beam emitted from the laser oscillator and propagates it toward a processing point; an output measurement unit that measures the output of leakage light of the laser beam that is not reflected by the reflection mirror and passes through it; and a focusing lens that converges the laser beam propagated through the reflection mirror and irradiates it to the workpiece, and the control unit measures the output of leakage light of the laser beam by using the output measurement unit while irradiating the workpiece with the laser beam.

[0008] Preferably, the control unit includes: a signal generating unit, which generates a signal for controlling the timing of pulse oscillation of the laser oscillator; and a signal synchronization unit, which synchronizes the signal generated by the signal generating unit with the timing of measuring the output of leakage light of the laser beam using the output measuring unit, and measures the output of leakage light of the laser beam using the output measuring unit only during the period when the laser oscillator oscillates pulse laser.

[0009] Preferably, the leakage light of the laser beam passes through a wavelength selective filter disposed in front of the output measurement unit and transmits only the laser beam having a wavelength used in processing, and enters the output measurement unit.

[0010] Preferably, the output measuring unit is constituted by a position detecting device (PSD: Position Sensing Device).

[0011] Preferably, the control unit further includes a warning notification unit configured to notify a warning when the output of the leakage light of the laser beam measured by the output measurement unit exceeds a predetermined threshold value.

[0012] Preferably, the output measuring unit measures the position information simultaneously with measuring the output of the leakage light of the laser beam.

[0013] Preferably, the control unit also includes at least one of a pass / fail judgment unit and a recording unit, wherein the pass / fail judgment unit judges whether the variation in the position of the leakage light of the laser beam measured by the output measurement unit is within a specified threshold range, and the recording unit records the data measured by the output measurement unit.

[0014] According to the present invention, it is possible to monitor the output of the laser beam during processing without interrupting the processing while processing a workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view showing a configuration example of a laser processing device according to an embodiment.

[0016] Figure 2 It is schematically shown Figure 1 FIG. 1 is a schematic diagram of a structure of a laser beam irradiation unit of a laser processing device.

[0017] Figure 3 This is a schematic graph showing an example of a measurement value by an output measurement unit according to the embodiment.

[0018] Figure 4 About Figure 3 The measured values ​​shown are schematic graphs showing an example of measured values ​​in synchronization with a pulse oscillating gate signal.

[0019] Figure 5 It is a schematic diagram showing an example of a measurement position of light leakage by an output measurement unit according to the embodiment.

[0020] Description of symbols

[0021] 1: laser processing device; 10: chuck table; 20: laser beam irradiation unit; 21: laser oscillator; 22: reflector; 23: focusing lens; 24: output measurement unit; 25: wavelength selection filter; 30: laser beam; 31: light leakage; 32: focusing point; 40: processing feed unit; 50: indexing feed unit; 60: shooting unit; 70: display unit; 80: control unit; 81: signal generation unit; 82: signal synchronization unit; 83: pass / fail judgment unit; 84: warning notification unit; 85: recording unit; 100: workpiece. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited by the contents described in the following embodiments. In addition, the constituent elements described below include contents that can be easily thought of by those skilled in the art, and substantially the same contents. In addition, the structures described below can be appropriately combined. In addition, various omissions, substitutions or changes in the structure can be made within the scope of the gist of the present invention.

[0023] First, the configuration of a laser processing device 1 according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 It is a perspective view showing a configuration example of the laser processing device 1 according to the embodiment. Figure 2 It is schematically shown Figure 1 Schematic diagram of the structure of the laser beam irradiation unit 20 of the laser processing device 1 shown. Figure 3 It is a schematic graph showing an example of the measurement value of the output measurement unit 24 according to the embodiment. Figure 4 About Figure 3 The measured values ​​shown are a schematic graph showing an example of measured values ​​when synchronized with the pulse oscillation selection signal 811. Figure 5 : is a schematic diagram showing an example of a measurement position of the light leakage 31 of the output measurement unit 24 according to the embodiment. In the following description, the X-axis direction is a direction on the horizontal plane. The Y-axis direction is a direction perpendicular to the X-axis direction on the horizontal plane. The Z-axis direction is a direction perpendicular to the X-axis direction and the Y-axis direction. The processing feed direction of the laser processing device 1 according to the embodiment is the X-axis direction, and the indexing feed direction is the Y-axis direction.

[0024] like Figure 1As shown, the laser processing device 1 includes a chuck table 10, a laser beam irradiation unit 20, a processing feed unit 40, a scale feed unit 50, a photographing unit 60, a display unit 70, and a control unit 80. The laser processing device 1 of the embodiment is a device that irradiates a workpiece 100 as a processing object with a laser beam 30 to process the workpiece 100. The processing of the workpiece 100 by the laser processing device 1 is, for example, a modified layer forming process in which a modified layer is formed inside the workpiece 100 by stealth cutting, a groove forming process in which a groove is formed on the front surface of the workpiece 100, or a cutting process in which the workpiece 100 is cut along a predetermined dividing line.

[0025] The object to be processed 100 is a wafer such as a semiconductor device wafer or an optical device wafer in the shape of a disk having a substrate such as silicon, sapphire, or gallium arsenide. The object to be processed 100 has: a plurality of predetermined division lines, which are set in a grid shape on the front side of the substrate; and a device, which is formed in an area divided by the predetermined division lines. The device is, for example, an integrated circuit such as IC (Integrated Circuit) or LSI (Large Scale Integration), an image sensor such as CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), or MEMS (Micro Electro Mechanical Systems). The object to be processed 100 is divided into individual devices along the predetermined division lines to manufacture a chip. The chip includes a portion of the substrate and the device on the substrate. The planar shape of the chip is, for example, a square or rectangular shape.

[0026] In the embodiment, the workpiece 100 to be processed by the laser processing device 1 is supported by the annular frame 101 and the expansion belt 102. The annular frame 101 has an opening larger than the outer diameter of the workpiece 100. The expansion belt 102 is attached to the back side of the annular frame 101. The expansion belt 102 includes, for example: a base material layer, which is composed of a synthetic resin with elasticity; and an adhesive layer, which is laminated on the base material layer and is composed of a synthetic resin with elasticity and adhesiveness. The workpiece 100 is positioned at a predetermined position of the opening of the annular frame 101, and the back side is attached to the expansion belt 102, thereby being fixed to the annular frame 101 and the expansion belt 102.

[0027] The chuck table 10 holds the workpiece 100 by means of a holding surface 11. The holding surface 11 is a disk-shaped surface formed of porous ceramics or the like. In an embodiment, the holding surface 11 is a plane parallel to the horizontal direction. The holding surface 11 is connected to a vacuum suction source, for example, via a vacuum suction path. The chuck table 10 suctions and holds the workpiece 100 placed on the holding surface 11. A plurality of clamping portions 12 for clamping an annular frame 101 supporting the workpiece 100 are arranged around the chuck table 10. The chuck table 10 is rotated around an axis parallel to the Z-axis direction by a rotating unit 13. The rotating unit 13 is supported by an X-axis moving plate 14. The rotating unit 13 and the chuck table 10 are moved in the X-axis direction by means of the X-axis moving plate 14 through the processing feed unit 40. The rotating unit 13 and the chuck table 10 are moved in the Y-axis direction by the indexing feed unit 50 via the X-axis direction moving plate 14 , the machining feed unit 40 , and the Y-axis direction moving plate 15 .

[0028] The laser beam irradiation unit 20 irradiates the workpiece 100 held by the chuck table 10 with a pulsed laser beam 30. The laser beam irradiation unit 20 includes a laser oscillator 21, a reflection mirror 22, a condenser lens 23, an output measurement unit 24, and a wavelength selection filter 25.

[0029] The laser oscillator 21 oscillates a pulsed laser having a predetermined wavelength for processing the workpiece 100. The laser beam 30 irradiated by the laser beam irradiation unit 20 may have a wavelength that is transparent to the workpiece 100 or a wavelength that is absorptive to the workpiece 100. The laser oscillator 21 includes, for example, a YAG laser oscillator, a YVO4 laser oscillator, or the like.

[0030] The reflector 22 reflects the laser beam 30 emitted from the laser oscillator 21 and propagates it toward the processing point of the workpiece 100 held by the holding surface 11 of the chuck table 10. For example, when the laser beam 30 emitted from the laser oscillator 21 is UV (ultraviolet), a reflective film that reflects UV is formed on the reflector 22. The reflective film formed on the reflector 22 reflects most of the laser beam 30, but allows about a few percent of the laser beam 30 to pass through without being reflected. In addition, even if the laser beam 30 emitted from the laser oscillator 21 is UV, it is sometimes mixed with light of wavelengths such as IR (infrared) or green. In this case, the reflector 22 allows the laser beam 30 other than UV, such as IR or green, to pass through without being reflected.

[0031] In the embodiment, the reflector 22 includes a first reflector 221, a second reflector 222, and a third reflector 223. The first reflector 221 reflects the laser beam 30 oscillated by the laser oscillator 21 as a first laser beam 301 toward the second reflector 222. The second reflector 222 reflects the first laser beam 301 reflected by the first reflector 221 as a second laser beam 302 toward the third reflector 223. The third reflector 223 reflects the second laser beam 302 reflected by the second reflector 222 as a third laser beam 303 toward the workpiece 100.

[0032] The condenser lens 23 condenses the laser beam 30 reflected by the reflector 22 to form a focal point 32 , and irradiates the workpiece 100 with the laser beam.

[0033] The output measurement unit 24 measures the output of the leakage light 31 of the laser beam 30 that is transmitted without being reflected by the reflection mirror 22. In addition, the output measurement unit 24 detects the measurement surface 245 (see Figure 5 ) in the resistor layer. In an embodiment, the output measurement unit 24 includes a position detection element (PSD: Position Sensing Device), but it can also be, for example, a thermopile power meter or a photodetector power meter. The PSD measures the current value of the current flowing through the incident light. For example, the control unit 80 described later converts the output of the leakage light 31 of the laser beam 30 according to the current value measured by the PSD. In the case where the output measurement unit 24 includes the PSD, the leakage light 31 of the laser beam 30 can be received by means of an ND (Neutral Density) filter that uniformly absorbs the amount of light. The PSD measures the position of the incident light according to the current ratios of the currents flowing in the resistor layer after being divided into four. For example, the control unit 80 described later determines the position of the incident light according to the current ratios measured by the PSD. In an embodiment, the output measurement unit 24 outputs the measurement result to the control unit 80 at regular time intervals.

[0034] In the embodiment, the output measurement unit 24 includes a first output measurement unit 241, a second output measurement unit 242, and a third output measurement unit 243. The first output measurement unit 241 measures the output of the leakage light 31 of the laser beam 30 that is not reflected by the first reflector 221 but is transmitted as the first leakage light 311. The second output measurement unit 242 measures the output of the leakage light 31 of the laser beam 30 that is not reflected by the second reflector 222 but is transmitted as the second leakage light 312. The third output measurement unit 243 measures the output of the leakage light 31 of the laser beam 30 that is not reflected by the third reflector 223 but is transmitted as the third leakage light 313.

[0035] The wavelength selection filter 25 is arranged in front of the output measurement unit 24. The wavelength selection filter 25 is a filter that transmits only the laser beam 30 of the wavelength used in the processing. For example, when the laser beam 30 emitted from the laser oscillator 21 is UV, the wavelength selection filter 25 transmits only UV. The wavelength selection filter 25 is, for example, any one of a bandpass filter, a dichroic filter, a longpass filter, and a shortpass filter, or a filter composed of a combination of these. The bandpass filter is a filter that arbitrarily selects a specific wavelength and transmits it. The dichroic filter is a filter that reflects light in a specific wavelength range and transmits light in the remaining wavelength range. The longpass filter is a filter that transmits light with a wavelength longer than a specified wavelength. The shortpass filter is a filter that transmits light with a wavelength shorter than a specified wavelength.

[0036] In the embodiment, the wavelength selection filter 25 includes a first wavelength selection filter 251, a second wavelength selection filter 252, and a third wavelength selection filter 253. The first wavelength selection filter 251 is disposed in front of the first output measurement unit 241. The first wavelength selection filter 251 transmits only the laser beam 30 of the wavelength used in the process among the first leakage light 311 of the laser beam 30. The second wavelength selection filter 252 is disposed in front of the second output measurement unit 242. The second wavelength selection filter 252 transmits only the laser beam 30 of the wavelength used in the process among the second leakage light 312 of the laser beam 30. The third wavelength selection filter 253 is disposed in front of the third output measurement unit 243. The third wavelength selection filter 253 transmits only the laser beam 30 of the wavelength used in the process among the third leakage light 313 of the laser beam 30.

[0037] like Figure 1 As shown, the processing feed unit 40 is a unit that moves the chuck table 10 and the laser beam irradiation unit 20 relative to each other in the X-axis direction, which is the processing feed direction. In an embodiment, the processing feed unit 40 moves the chuck table 10 in the X-axis direction. In an embodiment, the processing feed unit 40 is arranged on the device body 2 of the laser processing device 1. The processing feed unit 40 supports the X-axis direction moving plate 14 so that it can move freely in the X-axis direction. The processing feed unit 40 includes a well-known ball screw 41, a well-known pulse motor 42, and a well-known guide rail 43. The ball screw 41 is arranged to rotate freely around the axis. The pulse motor 42 rotates the ball screw 41 around the axis. The guide rail 43 supports the X-axis direction moving plate 14 so that it can move freely in the X-axis direction. The guide rail 43 is fixedly arranged on the Y-axis direction moving plate 15.

[0038] The indexing feed unit 50 is a unit that moves the chuck table 10 and the laser beam irradiation unit 20 relative to each other in the Y-axis direction, which is the indexing feed direction. In an embodiment, the indexing feed unit 50 moves the chuck table 10 in the Y-axis direction. In an embodiment, the indexing feed unit 50 is disposed on the device body 2 of the laser processing device 1. The indexing feed unit 50 supports the Y-axis direction moving plate 15 so as to be movable in the Y-axis direction. The indexing feed unit 50 includes a well-known ball screw 51, a well-known pulse motor 52, and a well-known guide rail 53. The ball screw 51 is arranged to be rotatable around an axis. The pulse motor 52 rotates the ball screw 51 around an axis. The guide rail 53 supports the Y-axis direction moving plate 15 so as to be movable in the Y-axis direction. The guide rail 53 is fixedly disposed on the device body 2.

[0039] The laser processing device 1 may further include a Z-axis moving unit for moving the focusing lens included in the laser beam irradiation unit 20 in the Z-axis direction. The Z-axis moving unit is provided on a column 3 erected from the device body 2, for example, and supports the focusing lens of the laser beam irradiation unit 20 so as to be movable in the Z-axis direction.

[0040] The imaging unit 60 images the workpiece 100 held by the chuck table 10. The imaging unit 60 includes a CCD camera or an infrared camera that images the workpiece 100 held by the chuck table 10.

[0041] The display unit 70 is a display unit composed of a liquid crystal display device or the like. The display unit 70 includes a display surface 71 and a notification unit 72. The display surface 71 displays the state or image of the processing action, etc. The notification unit 72 emits at least one of sound and light to notify the operator of the laser processing device 1 of the pre-set notification information. The notification unit 72 can be an external notification device such as a speaker or a light-emitting device. In the case where the display surface 71 includes a touch panel, the display unit 70 can include an input unit. The input unit can accept various operations of the operator to register processing content information, etc. The input unit can be an external input device such as a keyboard. The display unit 70 switches the information or image displayed on the display surface 71 according to the operation from the input unit, etc. The display unit 70 is connected to the control unit 80.

[0042] The control unit 80 controls the above-mentioned components of the laser processing device 1 respectively so that the laser processing device 1 performs processing actions on the workpiece 100. The control unit 80 controls the laser beam irradiation unit 20, the processing feed unit 40, the indexing feed unit 50, the imaging unit 60 and the display unit 70. The control unit 80 is a computer including an operation processing device as an operation unit, a storage device as a storage unit and an input / output interface device as a communication unit. The operation processing device includes, for example, a microprocessor such as a CPU (Central Processing Unit). The storage device has a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The operation processing device performs various operations according to a prescribed program stored in the storage device. The operation processing device outputs various control signals to the above-mentioned components via the input / output interface device according to the operation results to control the laser processing device 1.

[0043] The control unit 80 photographs the workpiece 100 through the photographing unit 60. The control unit 80 performs image processing on the image photographed by the photographing unit 60. The control unit 80 detects the predetermined dividing line of the workpiece 100 based on the image processing. The control unit 80 drives the processing feed unit 40 and the indexing feed unit 50 in such a manner that the focal point 32 of the laser beam 30 moves along the predetermined dividing line, and irradiates the laser beam 30 through the laser beam irradiation unit 20. While irradiating the laser beam 30 through the laser beam irradiation unit 20, the control unit 80 measures the output of the leakage light 31 of the laser beam 30 using the output measurement unit 24. In the embodiment, the control unit 80 includes a signal generating unit 81, a signal synchronizing unit 82, a pass / fail judging unit 83, a warning notifying unit 84, and a recording unit 85.

[0044] The signal generating section 81 generates a gate signal 811 for controlling the timing of pulse oscillation of the laser oscillator 21 of the laser beam irradiation unit 20. The signal generating section 81 outputs the gate signal 811 to the signal synchronizing section 82 and the recording section 85.

[0045] The signal synchronization unit 82 obtains the strobe signal 811 from the signal generation unit 81. In the embodiment, the signal synchronization unit 82 obtains the measurement result based on the output measurement unit 24 when receiving the strobe signal 811. The signal synchronization unit 82 synchronizes the strobe signal 811 generated by the signal generation unit 81 with the timing of measuring the output of the leakage light 31 of the laser beam 30 by the output measurement unit 24. The signal synchronization unit 82 outputs the measurement result based on the output measurement unit 24 synchronized with the strobe signal 811 to the pass / fail determination unit 83 and the recording unit 85.

[0046] The pass / fail judgment unit 83 obtains the measurement result based on the output measurement unit 24 in synchronization with the strobe signal 811 from the signal synchronization unit 82. The pass / fail judgment unit 83 judges whether the output of the leakage light 31 of the laser beam 30 measured by the output measurement unit 24 is within a predetermined threshold range 91. The threshold range 91 indicates the ratio of the leakage light 31 to the output of the laser beam 30. Figure 4 The leakage light 31 of the laser beam 30 is within a range between an upper threshold value 92 which is higher than the standard output 90 and a lower threshold value 93 which is lower than the standard output 90. Figure 4 In the example shown, when the output of the leakage light 31 of the laser beam 30 is lower than the lower limit threshold value 93, the pass / fail determination unit 83 determines that the output of the leakage light 31 of the laser beam 30 exceeds the range 91 of the predetermined threshold value. The pass / fail determination unit 83 outputs the determination result indicating that the output of the leakage light 31 of the laser beam 30 exceeds the range 91 of the predetermined threshold value to the warning notification unit 84 and the recording unit 85.

[0047] The pass / fail determination unit 83 also determines whether the position variation of the leak light 31 of the laser beam 30 measured by the output measurement unit 24 is within a predetermined threshold range 96. The predetermined threshold range 96 of the position variation is, for example, Figure 5 As shown in FIG. 1 , the range of the predetermined distance from the reference position 95 through which the optical axis of the standard laser beam 30 passes on the measurement surface 245 of the output measurement unit 24 is within the range perpendicular to the optical axis. The predetermined threshold range 96 of the position variation amount may be expressed as a perfect circle on the plane perpendicular to the optical axis, or may be expressed as Figure 5 For example, when the output measurement unit 24 includes a PSD, the amount of change in the position of the leak light 31 can be determined by a threshold value based on the ratio of each current flowing in the resistance layer of the PSD. Figure 5 In the example shown, a part of the leakage light 31 of the laser beam 30 measured by the output measurement unit 24 protrudes outside the range 96 of the predetermined threshold value. In this case, the pass / fail determination unit 83 determines that the variation amount of the position of the leakage light 31 of the laser beam 30 exceeds the range 96 of the predetermined threshold value. The pass / fail determination unit 83 outputs the determination result indicating that the variation amount of the position of the leakage light 31 of the laser beam 30 exceeds the range 96 of the predetermined threshold value to the warning notification unit 84 and the recording unit 85.

[0048] The control unit 80 stops the oscillation of the laser beam 30 from the laser oscillator 21 during the period when the chuck table 10 is indexed and fed in the Y-axis direction during the laser processing by the laser processing device 1. Figure 3 As shown, in the case where the output measurement unit 24 always measures the output of the leakage light 31 of the laser beam 30, when the strobe signal 811 is off, the output measurement value of the output measurement unit 24 is substantially zero.

[0049] The signal synchronization unit 82 synchronizes the gate signal 811 with the timing of measuring the output of the leakage light 31 of the laser beam 30, thereby excluding the output measurement value when the gate signal 811 is off. That is, the signal synchronization unit 82 determines whether the output of the leakage light 31 of the laser beam 30 is within the range 91 of the predetermined threshold value based only on the output measurement value of the output measurement unit 24 in the time band 812 when the pulse is oscillated from the laser oscillator 21. Figure 4 As shown, it is possible to perform quantitative evaluation of the output measurement value. More specifically, it is possible to evaluate whether the output of the leakage light 31 of the laser beam 30 measured by the output measurement unit 24 is within the range of output suitable for processing.

[0050] For example, when the output of the leakage light 31 is lower than the lower threshold value 93, it is possible to predict a decrease in the output of the laser oscillator 21 or a defect in the optical element. For example, when the output of the leakage light 31 is higher than the upper threshold value 92, it is possible to predict a breakage of the reflective film of the reflector 22 or a fall-off of the optical element itself. In addition, by comparing the output measurement values ​​of the first output measurement unit 241, the second output measurement unit 242, and the third output measurement unit 243, it is easy to find out the cause of the output decrease.

[0051] The warning notification unit 84 acquires the determination result of the pass / fail determination unit 83. When the pass / fail determination unit 83 determines that at least one of the output and the position variation of the leakage light 31 of the laser beam 30 measured by the output measurement unit 24 exceeds the predetermined threshold range 91, 96, the warning notification unit 84 notifies the notification unit 72 of the preset warning information. When the pass / fail determination unit 83 determines that the measurement result of at least one output measurement unit 24 among the plurality of output measurement units 241, 242, 243 exceeds the predetermined threshold range 91, 96, the warning notification unit 84 notifies the notification unit 72 of the preset warning information.

[0052] exist Figure 4 In the example shown, for example, when the output of the leakage light 31 of the laser beam 30 is lower than the lower limit threshold value 93, the warning notification unit 84 obtains the determination result indicating that the output of the leakage light 31 of the laser beam 30 exceeds the range 91 of the predetermined threshold value from the pass / fail determination unit 83. The warning notification unit 84 notifies the notification unit 72 of the predetermined warning information indicating that the output of the leakage light 31 of the laser beam 30 is lower than the lower limit threshold value 93 based on the obtained determination result of the pass / fail determination unit 83. Figure 5In the example shown, for example, the warning notification unit 84 obtains a determination result indicating that a part of the leakage light 31 of the laser beam 30 has protruded outside the range 96 of the predetermined threshold value from the pass / fail determination unit 83. Based on the obtained determination result of the pass / fail determination unit 83, the warning notification unit 84 notifies the notification unit 72 of the predetermined warning information indicating that a part of the leakage light 31 of the laser beam 30 has protruded outside the range 96 of the predetermined threshold value.

[0053] The recording unit 85 acquires and records data such as the measurement result of the output measurement unit 24, the strobe signal 811 generated by the signal generation unit 81, the measurement result of the output measurement unit 24 synchronized by the signal synchronization unit 82, and the determination result of the pass / fail determination unit 83. The measurement result data includes, for example, the output measurement value of the light leakage 31 of the laser beam 30 of each output measurement unit 24 and the time series data of the incident position. The control unit 80 can display the data recorded by the recording unit 85 on the display surface 71 of the display unit 70.

[0054] As described above, the laser processing apparatus 1 of the embodiment irradiates the workpiece 100 with the laser beam 30, and measures the output of the leakage light 31 of the laser beam 30 that is not reflected by the reflector 22 but is transmitted through the reflector 22 by the output measurement unit 24. The laser processing apparatus 1 uses the leakage light 31 of the laser beam 30 that is transmitted through the reflector 22 in the output measurement, and can monitor the output of the laser beam 30 during processing without interrupting the processing while processing the workpiece 100. Therefore, for example, a decrease in output during processing, damage to an optical element, etc. can be quickly discovered, and processing defects of the workpiece 100 can be suppressed.

[0055] In addition, the output of the first leakage light 311 transmitted through the reflector 22 (first reflector 221) immediately behind the emission port of the laser oscillator 21 and the second leakage light 312 or the third leakage light 313 transmitted through the reflector 22 (second reflector 222 or third reflector 223) after passing through the plurality of optical elements can be measured by the plurality of output measurement units 24. Thus, the leakage lights 31 transmitted through the respective reflectors 22 provided between the emission port of the laser oscillator 21 and the light-converging point 32 of the laser beam 30 can be compared, and the cause of the output reduction can be easily found. More specifically, it is possible to distinguish whether the output reduction is caused by the deterioration of the laser oscillator 21 or by the optical element on the way to the light-converging point 32.

[0056] The present invention is not limited to the above-described embodiment, and can be implemented with various modifications within the scope of the present invention.

[0057] For example, in the present invention, the signal synchronization unit 82 can cause the output measurement unit 24 to measure the output of the leakage light 31 of the laser beam 30 and obtain the measurement result only in the time band 812 when the strobe signal 811 is received. In this case, the output measurement unit 24 controls the timing of measuring the output through the signal synchronization unit 82.

[0058] In addition, in the embodiment, the pass / fail judgment unit 83 judges whether the output and the position variation of the leakage light 31 of the laser beam 30 are within the threshold ranges 91 and 96, respectively, but in the present invention, it is also possible to judge only one of the output and the position variation. In this case, the warning notification unit 84 notifies the notification unit 72 of a warning when one of the judgments made by the pass / fail judgment unit 83 exceeds the threshold ranges 91 and 96. In addition, in the embodiment, the respective threshold ranges 91 and 96 are set for the output and the position variation of the leakage light 31 of the laser beam 30, but in the present invention, it is also possible to set a threshold range based on a combination of the output and the position variation.

[0059] In addition, in the embodiment, the warning notification unit 84 notifies the notification unit 72 of a predetermined warning message when the pass / fail judgment unit 83 determines that the measurement result of at least one output measurement unit 24 among the multiple output measurement units 241, 242, 243 exceeds the specified threshold range 91, 96. However, in the present invention, the warning notification unit 84 may also notify the notification unit 72 of a predetermined warning message when the pass / fail judgment unit 83 determines that the measurement results of all the output measurement units 241, 242, 243 exceed the specified threshold range 91, 96.

Claims

1. A laser processing device, wherein: The laser processing device has: A chuck table, which holds the workpiece; a laser beam irradiation unit for irradiating a workpiece held by the chuck table with a pulsed laser beam; A processing feeding unit, which performs processing feeding relative to the chuck table and the laser beam irradiation unit; An indexing feeding unit that indexes and feeds the chuck table and the laser beam irradiation unit relatively; and Control unit, The laser beam irradiation unit comprises: Laser oscillator; a plurality of reflecting mirrors that reflect the laser beam emitted from the laser oscillator and propagate the laser beam toward a processing point; a plurality of output measuring units for measuring the output of leakage light of the laser beam that is not reflected by each of the reflecting mirrors but is transmitted therethrough; and A condenser lens is used to condense the laser beam propagated through the plurality of reflectors and irradiate the laser beam to the workpiece. The control unit contains: a pass / fail determination unit for determining whether the output of the leakage light of the laser beam measured by the output measurement unit is within a predetermined threshold value; as well as a warning notification unit configured to notify the notification unit of a preset warning message when the pass / fail determination unit determines that the measurement result of at least one of the plurality of output measurement units exceeds a predetermined threshold value; The output of the leaked light of the laser beam is measured by the output measuring unit while the workpiece is irradiated with the laser beam.

2. The laser processing device according to claim 1, wherein: The control unit contains: a signal generating unit that generates a signal for controlling the timing of pulse oscillation of the laser oscillator; and a signal synchronizing unit that synchronizes the signal generated by the signal generating unit with the timing of measuring the output of the leakage light of the laser beam by the output measuring unit, The output of the leaked light of the laser beam is measured by the output measuring unit only during the period when the pulse laser light is oscillated from the laser oscillator.

3. The laser processing device according to claim 1 or 2, wherein: The leaked light of the laser beam passes through a wavelength selective filter disposed in front of the output measurement unit and transmits only the laser beam having a wavelength used in processing, and enters the output measurement unit.

4. The laser processing device according to claim 1 or 2, wherein: The output measurement unit is a position detection element.

5. The laser processing device according to claim 1 or 2, wherein: The output measuring unit measures the position information simultaneously with measuring the output of the leakage light of the laser beam.

6. The laser processing device according to claim 5, wherein: The pass / fail determination unit determines whether the variation of the position of the leaked light of the laser beam measured by the output measurement unit is within a predetermined threshold value, and The control unit further includes a recording unit that records the data measured by the output measurement unit.

7. The laser processing device according to claim 1 or 2, wherein: The pass / fail determination unit determines whether the variation of the position of the leaked light of the laser beam measured by the output measurement unit is within a predetermined threshold value, and The warning notification unit notifies the notification unit of preset warning information when the pass / fail determination unit determines that at least one of the output and position variation of the leakage light of the laser beam measured by the output measurement unit exceeds a predetermined threshold value.

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