Laser processing device

Abstract

The present application provides a laser processing apparatus capable of accurately measuring the output of a laser beam after passing through a condenser lens without reducing productivity. The laser processing apparatus includes a chuck table that holds a workpiece, a laser beam irradiation unit that irradiates a laser beam to the workpiece, an output measurement unit that measures the output of the laser beam, and a control unit that controls each constituent element, the control unit having a storage section that stores, as data, the change in output accompanying the change in time from the time when the laser beam is irradiated to the output measurement unit, and a prediction section that predicts the equilibrium output (52) of the output of the laser beam based on the data stored in the storage section from the output of the laser beam (21) for a prediction time (54) shorter than a prescribed time (53).

Description

TECHNICAL FIELD

[0001] The present application relates to a laser processing apparatus. BACKGROUND

[0002] In order to process a workpiece such as a semiconductor wafer, a method of forming a processing groove by irradiating a laser beam having a wavelength that is absorbed by the workpiece and performing dicing, and a method of forming a modified layer as a dicing starting point by converging and irradiating a laser beam having a wavelength that is transmitted through the workpiece to the inside of the workpiece and performing dicing are proposed (see Patent Literature 1 and Patent Literature 2).

[0003] In the laser processing apparatus described above, if the output of the laser beam changes, it can lead to dicing failure of the workpiece and the like. Therefore, it is very important to confirm that the set output of the laser beam is the same as the actual output. Therefore, a method of measuring the output of the laser beam using a power meter is proposed (see, for example, Patent Literature 3).

[0004] However, the power meter shown in Patent Literature 3 and the like used in the output measurement of the laser beam is heated by the laser beam received by a light receiving surface, converts the heat of the light receiving surface into an electric signal, and performs output measurement. It takes about 4 seconds from the start of measurement to make the output of the laser beam as a measurement result a constant value. In addition, the power meter described above needs to cut off the optical path or interrupt the processing to irradiate the laser beam to the power meter using the power meter itself in order to measure the output of the laser beam. Therefore, the power meter shown in Patent Literature 3 and the like repeatedly performs the measurement described above, and there is a problem that the number of processed wafers per unit time, that is, the production rate, decreases.

[0005] Therefore, a method of monitoring the output of the laser beam using the transmitted light of a mirror without interrupting the processing is proposed (see Patent Literature 4).

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2003-320466

[0007] Patent Literature 2: Japanese Patent No. 3408805

[0008] Patent Literature 3: Japanese Patent Application Publication No. 2009-291818

[0009] Patent Literature 4: Japanese Patent Application No. 2019-155067

[0010] If the method shown in Patent Literature 4 is used, it is possible to measure the output while processing the workpiece. However, in the case where the method shown in Patent Literature 4 is used, the laser beam actually used for processing is the laser beam that has passed through the condenser lens, and the laser beam for which the output is measured is the laser beam before passing through the condenser lens, so in the case where a bad situation in which dirt adheres to the condenser lens or the like occurs, there is still a problem that the output of the laser beam actually irradiated to the workpiece cannot be accurately measured. SUMMARY

[0011] The present application has been achieved in view of the above-described circumstances, and an object thereof is to provide a laser processing apparatus capable of accurately measuring the output of a laser beam after passing through a condenser lens without reducing productivity.

[0012] To solve the above-described problem and achieve the object, a laser processing apparatus according to the present application is characterized by including: 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 processes the chuck table in opposition to the laser beam irradiation unit; an indexing feed unit that indexes the chuck table in opposition to the laser beam irradiation unit; an output measurement unit that measures the output of the laser beam; and a control unit that controls each constituent element, the laser beam irradiation unit including: a laser oscillator; and a condenser lens that condenses a laser beam oscillated from the laser oscillator to irradiate to the workpiece, the output measurement unit being disposed at a position at which the laser beam after passing through the condenser lens can be measured, the control unit having: a storage section that stores, as data, the time from the irradiation of the laser beam to the output measurement unit and the change in the output accompanying the time; and a prediction section that predicts, based on the data stored in the storage section, the output at which the output of the laser beam no longer changes, from the output of the laser beam at a time shorter than the time required for the output to stabilize.

[0013] In the laser processing apparatus, the output measurement unit can be disposed adjacent to the chuck table, and the control unit can further have a movement control section that controls the movement distance of the processing feed unit so that the laser beam passes through the workpiece held by the chuck table and a light-receiving section of the output measurement unit, when processing the workpiece.

[0014] The laser processing apparatus of the present application is characterized in that the laser processing apparatus includes: a chuck table that holds a workpiece; a laser beam irradiation unit that irradiates a pulsed laser beam toward the workpiece held by the chuck table; a processing feed unit that processes the chuck table in feed with respect to the laser beam irradiation unit; an indexing feed unit that indexes the chuck table in feed with respect to the laser beam irradiation unit; an output measurement unit that measures an output of the laser beam; and a control unit that controls each of the constituent elements, the laser beam irradiation unit includes: a laser oscillator; and a condenser lens that condenses a laser beam oscillated from the laser oscillator to irradiate the workpiece, the output measurement unit includes: a power meter that is disposed at a position at which the laser beam after passing through the condenser lens can be measured, and has a light-receiving portion that directly receives the laser beam; and a photodiode that has a light-receiving portion that receives scattered light of the laser beam, the control unit has: a storage portion that stores correlation data of an actual laser beam output measured by the power meter and an output of the scattered light of the laser beam measured by the photodiode; and a prediction portion that calculates the actual laser beam output from the output of the scattered light of the laser beam based on the correlation data stored in the storage portion.

[0015] The present application achieves the following effects: the output of the laser beam after passing through the condenser lens can be accurately measured without reducing productivity. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a perspective view showing a configuration example of the laser processing apparatus of Embodiment 1.

[0017] Figure 2 is a diagram for explaining a configuration of the laser beam irradiation unit of the laser processing apparatus shown in Figure 1

[0018] Figure 3 is a diagram showing an example of the output of the laser beam represented by the electric signal output from the laser beam irradiation unit shown in Figure 2

[0019] is a top view schematically showing the irradiation position of the laser beam of the laser beam irradiation unit on the workpiece of the laser processing apparatus shown in Figure 4 Figure 1

[0020] Figure 5 is a side view schematically showing the laser beam irradiated by the laser beam irradiation unit and the workpiece shown in Figure 4

[0021] Figure 6 is a perspective view showing the output measurement unit of the laser processing apparatus of Embodiment 2.​​​​

[0022] Figure 7 This is a diagram showing data stored in the storage unit of the control unit of the laser processing apparatus according to the second embodiment.

[0023] Label Description

[0024] 1: Laser processing device; 10: Chuck table; 20: Laser beam irradiation unit; 21: Laser beam; 22: Laser oscillator; 23: Converging lens; 31: X-axis moving unit (processing feed unit); 32: Y-axis moving unit (indexing feed unit); 50: Output measuring unit; 51: Light receiving unit; 52: Balanced output (output when stable and no longer changing, actual output of the laser beam); 53: Specified time (equivalent to the time required for the output to stabilize); 54: Prediction time (short time); 55: Output before balance (short time output of the laser beam); 70: Photodiode; 100: Control unit; 101: Storage unit; 102: Prediction unit; 103: Movement control unit; 104: Data; 104-2: Data (related data); 211: Converging point; 212: Scattered light; 200: Workpiece. DETAILED DESCRIPTION

[0025] The modes (embodiments) for implementing 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 constituent elements that can be easily imagined by those skilled in the art, as well as substantially the same constituent elements. Furthermore, the structures described below can be appropriately combined. In addition, various omissions, replacements or changes in the structure can be made without departing from the scope of the present invention.

[0026] [Implementation Method 1]

[0027] A laser processing apparatus according to a 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. Figure 1 : is a perspective view showing a configuration example of a laser processing apparatus according to Embodiment 1. Figure 1 The laser processing apparatus 1 shown is an apparatus for laser processing a workpiece 200 by irradiating the workpiece 200 with a pulsed laser beam 21 .

[0028] (Workpiece)

[0029] As Figure 1 The workpiece 200 to be processed by the laser processing apparatus 1 shown is a wafer such as a disk-shaped semiconductor wafer or an optical device wafer having a substrate 201 made of silicon, sapphire, gallium arsenide, or the like. Figure 1As shown, a workpiece 200 includes predetermined dividing lines 203 arranged in a grid pattern on a front surface 202 of a substrate 201, and devices 204 formed in regions defined by the predetermined dividing lines 203. Devices 204 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integrations), or image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors).

[0030] In the first embodiment, a workpiece 200 has a circular plate-shaped adhesive tape 208 attached to its outer edge, which has a diameter larger than the outer diameter of the workpiece 200 and a ring frame 210 attached to its back surface 205 on the back side of its front surface 202. The workpiece 200 is supported within an opening 207 of the ring frame 210. In the first embodiment, the workpiece 200 is divided into individual components 204 along the planned dividing lines 203.

[0031] like Figure 1 As shown, the laser processing apparatus 1 includes a chuck table 10 , a laser beam irradiation unit 20 , a moving unit 30 , an imaging unit 40 , an output measurement unit 50 , and a control unit 100 . The chuck table 10 holds a workpiece 200 using a holding surface 11 .

[0032] The chuck table 10 holds the workpiece 200 using a holding surface 11. The holding surface 21 is in the shape of a disk formed of porous ceramics or the like and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown). The chuck table 10 suctions and holds the workpiece 200 placed on the holding surface 11. In embodiment 1, the holding surface 11 is a plane parallel to the horizontal direction. A plurality of clamping portions 12 are arranged around the chuck table 10, and the clamping portions 12 clamp an annular frame 210 that supports the workpiece 200 in the opening 207.

[0033] The chuck table 10 is rotated about an axis perpendicular to the holding surface 11 and parallel to the Z-axis direction parallel to the vertical direction by the rotational movement unit 34 of the movement unit 30. The chuck table 10 is moved in the X-axis direction parallel to the horizontal direction by the X-axis movement unit 31 of the movement unit 30 together with the rotational movement unit 34, and is moved in the Y-axis direction parallel to the horizontal direction and perpendicular to the X-axis direction by the Y-axis movement unit 32.

[0034] 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 is a laser beam irradiation component that irradiates the workpiece 200 with a pulsed laser beam 21 of a wavelength that is transparent to the workpiece 200, thereby forming a modified layer inside the workpiece 200 that serves as a starting point for fracture. The modified layer refers to a region in which the density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding physical properties. Examples of the modified layer include a melt-processed region, a crack region, a dielectric breakdown region, a refractive index change region, and a region where these regions are mixed. In the embodiment, the mechanical strength of the modified layer is lower than that of other parts of the substrate 201.

[0035] In the first embodiment, the laser beam irradiation unit 20 irradiates the laser beam 21 of a wavelength that is transparent to the workpiece 200. However, in the present invention, the laser beam 21 of a wavelength that is absorptive may be irradiated to ablate the workpiece 200. In the first embodiment, as Figure 1 As shown, a portion of the laser beam irradiation unit 20 is supported by a lifting member 4 that moves in the Z-axis direction via a Z-axis moving unit 33 of a moving unit 30 provided on a standing wall 3 standing from the apparatus main body 2 .

[0036] Next, the structure of the laser beam irradiation unit 20 will be described. Figure 2 Yes Figure 1 1 and 2 are explanatory diagrams for explaining a schematic configuration of a laser beam irradiation unit of a laser processing apparatus shown in FIG. Figure 3 It shows Figure 2 FIG. 1 is a diagram showing an example of laser beam output represented by an electrical signal output from a laser beam irradiation unit.

[0037] like Figure 2 As shown, the laser beam irradiation unit 20 includes: a laser oscillator 22, which oscillates a pulsed laser beam 21 for processing a workpiece 200; a focusing lens 23, which converges the laser beam 21 oscillated from the laser oscillator 22 and irradiates the workpiece 200 held on the holding surface 11 of the chuck worktable 10; an attenuator (also called an attenuator) 24, which is arranged on the optical path of the laser beam 21 between the laser oscillator 22 and the focusing lens 23, and attenuates the laser beam 21 oscillated from the laser oscillator 22; and a reflector 25, which reflects the laser beam 21 attenuated by the attenuator 24 toward the focusing lens 23.

[0038] The condenser lens 23 is disposed at a position facing the holding surface 11 of the chuck table 10 in the Z-axis direction, and transmits the laser beam 21 oscillated from the laser oscillator 22 to condense the laser beam 21 at a condensing point 211 .

[0039] likeFigure 2 As shown in the figure, the attenuator 24 has a hollow motor 26, a λ / 2 wavelength plate 27, a beam splitter 28, and a beam damper 29. The hollow motor 26 is formed in a circular ring shape through which the laser beam 21 oscillated by the laser oscillator 22 passes. The λ / 2 wavelength plate 27 is rotated by the hollow motor 26 with the optical axis of the laser beam 21 oscillated by the laser oscillator 22 as the center. The λ / 2 wavelength plate 27 imparts a phase difference of λ / 2 (180°) to the laser beam 21 and causes the laser beam 21 to be emitted.

[0040] The beam splitter 28 reflects the laser beam 21 of S-polarized light among the laser beam 21 that has passed through the λ / 2 wavelength plate 27 toward the beam damper 29 and transmits the laser beam 21 of P-polarized light toward the mirror 25. The beam damper 29 causes the laser beam 21 of S-polarized light reflected by the beam splitter 28 to be terminated.

[0041] The moving unit 30 relatively moves the laser beam irradiation unit 20 and the chuck table 10 in the X-axis direction, the Y-axis direction, the Z-axis direction, and around the axis parallel to the Z-axis direction. The X-axis direction and the Y-axis direction are directions parallel to the holding surface 11. The moving unit 30 has an X-axis moving unit 31 as a machining feed unit that moves the chuck table 10 in the X-axis direction, a Y-axis moving unit 32 as an indexing feed unit that moves the chuck table 10 in the Y-axis direction, a Z-axis moving unit 33 that moves the condenser lens 23 included in the laser beam irradiation unit 20 in the Z-axis direction, and a rotational moving unit 34 that rotates the chuck table 10 around the axis parallel to the Z-axis direction.

[0042] The Y-axis moving unit 32 is a unit that indexes feeds the chuck table 10 and the laser beam irradiation unit 20 relative to each other. In Embodiment 1, the Y-axis moving unit 32 is provided on the device main body 2 of the laser processing device 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.

[0043] The X-axis moving unit 31 is a unit that machining feeds the chuck table 10 and the laser beam irradiation unit 20 relative to each other. The X-axis moving unit 31 is provided on the moving plate 15. The X-axis moving unit 31 supports the second moving plate 16 that supports the rotational moving unit 34 that rotates the chuck table 10 around the axis parallel to the Z-axis direction so as to be movable in the X-axis direction. The Z-axis moving unit 33 is provided on the standing wall 3 and supports the elevation member 4 so as to be movable in the Z-axis direction.

[0044] The X-axis moving unit 31, the Y-axis moving unit 32, and the Z-axis moving unit 33 have a publicly known ball screw provided so as to be rotatable about an axis, a publicly known pulse motor that rotates the ball screw about the axis, and a publicly known guide rail that supports the moving plates 15 and 16 so as to be movable in the X-axis direction or the Y-axis direction and supports the lifting member 4 so as to be movable in the Z-axis direction.

[0045] In addition, the laser processing apparatus 1 has an X-axis direction position detection unit (not shown) for detecting the position of the chuck table 10 in the X-axis direction, a Y-axis direction position detection unit (not shown) for detecting the position of the chuck table 10 in the Y-axis direction, and a Z-axis direction position detection unit that detects the position of the condenser lens 23 included in the laser beam irradiation unit 20 in the Z-axis direction. Each of the position detection units outputs the detection result to the control unit 100.

[0046] The photographing unit 40 photographs the workpiece 200 held by the chuck table 10. The photographing unit 40 has a photographing element such as a CCD (Charge Coupled Device) photographing element or a CMOS (Complementary Metal Oxide Semiconductor) photographing element that photographs the workpiece 200 held by the chuck table 10. In Embodiment 1, the photographing unit 40 is mounted to the front end of the housing of the laser beam irradiation unit 20 and is disposed at a position parallel to the condenser lens 23 of the laser beam irradiation unit 20 in the X-axis direction as shown in FIG. 1. Figure 2 The photographing unit 40 photographs the workpiece 200 and obtains an image for performing alignment in which the workpiece 200 and the laser beam irradiation unit 20 are aligned with each other, and outputs the obtained image to the control unit 100.

[0047] The output measurement unit 50 is a unit that measures the output of the laser beam 21. The output measurement unit 50 has a light receiving portion 51 that receives the laser beam 21 emitted from the laser oscillator 22 and propagated by means of the attenuator 24, the mirror 25, the condenser lens 23, and the like. The light receiving portion 51 is disposed at a position apart from the inside of the workpiece 200 held by the chuck table 10 by a prescribed distance in the Z-axis direction with respect to the condensing point 211. In Embodiment 1, the light receiving portion 51 is disposed at a position apart from the condensing point 211 by a prescribed distance downward.

[0048] The output measuring unit 50 is a power meter that heats the light-receiving portion 51 by the laser beam 21 and converts the heat of the light-receiving portion 51 into an electric signal. The output measuring unit 50 outputs the converted electric signal toward the control unit 100. In Embodiment 1, the electric signal output from the output measuring unit 50 is an electric signal corresponding to the output of the laser beam 21 received by the light-receiving portion 51. In this way, the output measuring unit 50 measures the output of the laser beam 21 by outputting the above-described electric signal to the control unit 100.

[0049] In addition, in the output measuring unit 50 in Embodiment 1, the light-receiving portion 51 is disposed upward on the second moving plate 16. In Embodiment 1, the output measuring unit 50 is disposed with the light-receiving portion 51 upward on the second moving plate 16, so as to be arranged so as to be able to measure the position of the laser beam 21 after passing through the condenser lens 23. In addition, in the output measuring unit 50 in Embodiment 1, the light-receiving portion 51 is arranged at a position parallel to at least one of the division predetermined lines 203 of the workpiece 200 held by the holding surface 11 in the X-axis direction. In this way, in the present application, the light-receiving portion 51 is arranged at a position parallel to at least one of the division predetermined lines 203 of the workpiece 200 held by the holding surface 11 in the X-axis direction is indicative of the output measuring unit 50 being arranged adjacent to the chuck table 10.

[0050] The control unit 100 controls the above-described components of the laser processing apparatus 1 respectively, and causes the laser processing apparatus 1 to perform a processing operation on the workpiece 200. In addition, the control unit 100 is a computer having an arithmetic processing device having a microprocessor like a CPU (central processing unit), a storage device having a memory like a ROM (read only memory) or a RAM (random access memory), and an input / output interface device. The arithmetic processing device of the control unit 100 performs an arithmetic processing in accordance with a computer program stored in the storage device, and outputs a control signal for controlling the laser processing apparatus 1 to the above-described components of the laser processing apparatus 1 via the input / output interface device, thereby realizing the functions of the control unit 100.

[0051] In addition, the control unit 100 is connected to a display unit 110 constituted by a liquid crystal display device or the like that displays a state of a processing operation, an image, or the like, and an unillustrated input unit used when an operator registers processing content information or the like. The input unit is constituted by at least one of a touch panel and an external input device like a keyboard provided to the display unit 110.

[0052] The control unit 100 converts the electric signal from the output measuring unit 50 into the output of the laser beam 21. The output of the laser beam 21 converted by the control unit 100 is, for example, an output of the laser beam 21 per unit time.Figure 3 As shown by the middle dashed line, since the output measurement unit 50 is a so-called power meter in which the light receiving unit 51 is heated by the laser beam 21 and converts the heat into an electrical signal corresponding to the output of the laser beam 21, it takes a predetermined time 53 (equivalent to the time required for the output to stabilize) from the time the light receiving unit 51 starts receiving the laser beam 21 to the time the balanced output 52 (the output is stable and does not rise further) is reached. This balanced output 52 is the output of the laser beam 21 of the laser beam irradiation unit 20 that the output measurement unit 50 wants to measure. Figure 3 The horizontal axis in FIG is the time elapsed since the light receiving unit 51 starts to receive the laser beam 21. Figure 3 The vertical axis in is the output of the laser beam 21 converted by the control unit 100 .

[0053] In addition, if Figure 1 As shown in FIG. 1 , the control unit 100 includes a storage unit 101 and a prediction unit 102. The storage unit 101 stores the elapsed time since the light receiving unit 51 of the output measurement unit 50 received the laser beam 21 and the change in the output of the laser beam 21 after the conversion of the electric signal from the output measurement unit 50 as the elapsed time changes as data 104. That is, the storage unit 101 stores data 104 similar to the data for predicting the body temperature before the so-called prediction thermometer reaches the equilibrium temperature. For example, the data 104 is used to predict the body temperature based on the prediction time 54 ( Figure 3 The mathematical formula for predicting the balanced output 52 is shown in FIG. 5 , which is based on the pre-balanced output 55 of the laser beam 21 converted from the electrical signal from the output measurement unit 50 at the time of FIG. 1 . Furthermore, if the predicted time 54 is shorter than the specified time 53, the pre-balanced output 55 is lower than the balanced output 52.

[0054] The prediction unit 102 predicts a balanced output 52 at which the output of the laser beam 21 does not change, based on the output 55 before balancing, which is the output of the laser beam 21 at a predicted time 54 shorter than the predetermined time 53 required for the output to stabilize. Specifically, the prediction unit 102 calculates the balanced output 52 at which the output of the laser beam 21 does not change, based on the output 55 before balancing, which is obtained by converting the electrical signal from the output measuring unit 50 at the predicted time 54, and referring to the data 104 stored in the storage unit 101. Figure 3 The balanced output 52 is predicted as indicated by the solid line. In this way, the prediction unit 102 of the control unit 100 predicts the balanced output 52 before the balanced output 52 is reached.

[0055] Further, the control unit 100 has a movement control section 103. The movement control section 103 controls the movement distance in the X direction of the chuck table 10 based on the X-axis movement unit 31 so that the laser beam 21 passes through the work 200 held by the chuck table 10 and the light receiving section 51 of the output measurement unit 50 when the work 200 is machined by irradiating the laser beam 21 to each of the division intended lines 203. Specifically, the movement control section 103 calculates the division intended line 203 of the work 200 held by the chuck table 10 which is parallel to the division intended line 203 of the light receiving section 51 of the output measurement unit 50 in the X-axis direction based on the machining content information.

[0056] In a case where the division intended line 203 of the work 200 held by the chuck table 10 which is parallel to the division intended line 203 of the light receiving section 51 of the output measurement unit 50 in the X-axis direction is one, the movement control section 103 controls the movement unit 30 so that the laser beam 21 is irradiated to the one division intended line 203 from the outer edge of the work 200 toward the upper side of the light receiving section 51 of the output measurement unit 50. The control unit 100 temporarily stops the irradiation of the laser beam 21 when the laser beam irradiation unit 20 is from the outer edge of the work 200 toward the upper side of the light receiving section 51 of the output measurement unit 50, and starts the irradiation of the laser beam 21 again on the light receiving section 51.

[0057] In a case where the division intended line 203 of the work 200 held by the chuck table 10 which is parallel to the division intended line 203 of the light receiving section 51 of the output measurement unit 50 in the X-axis direction is one, the movement control section 103 controls the movement unit 30 so that the laser beam 21 is irradiated to the one division intended line 203 from the outer edge of the work 200 toward the upper side of the light receiving section 51 of the output measurement unit 50. The control unit 100 temporarily stops the irradiation of the laser beam 21 when the laser beam irradiation unit 20 is from the outer edge of the work 200 toward the upper side of the light receiving section 51 of the output measurement unit 50, and starts the irradiation of the laser beam 21 again on the light receiving section 51.

[0058] Further, in a case where there are a plurality of the division intended lines 203 in the division intended lines 203 of the workpiece 200 held by the chuck table 10 that are parallel to the light receiving section 51 of the output measuring unit 50 in the X-axis direction, the movement control section 103 calculates the division intended line 203 that is closest to the center in the Y-axis direction of the light receiving section 51, and controls each of the components as described above when the laser beam 21 is irradiated to the closest division intended line 203. In this way, in the embodiment, when the laser beam 21 is irradiated to any one of the division intended lines 203 of the workpiece 200, the movement control section 103 relatively moves the chuck table 10 and the laser beam irradiation unit 20 in the X-axis direction that is the machining feed direction, and irradiates the laser beam 21 to the light receiving section 51. Further, in the embodiment 1, the movement control section 103 relatively moves the chuck table 10 and the laser beam irradiation unit 20 in the Y-axis direction that is the indexing feed direction in a state where the laser beam 21 is irradiated to the light receiving section 51.

[0059] Further, the functions of the storage section 101 are implemented by the storage device described above. The functions of the prediction section 102 and the movement control section 103 are implemented by the arithmetic processing device by performing arithmetic processing according to the computer program stored in the storage device.

[0060] Next, the machining operation of the laser machining device 1 described above will be described. Figure 4 is a plan view schematically showing Figure 1 the irradiation position of the laser beam of the laser beam irradiation unit on the workpiece of the laser machining device shown in Figure 5 is a side view schematically showing Figure 4 the laser beam irradiated by the laser beam irradiation unit and the workpiece. Further, in Figure 4 the division intended lines 203 are omitted.

[0061] In the laser machining device 1 described above, the operator registers the machining content information in the control unit 100, places the workpiece 200 on the holding surface 11 of the chuck table 10 through the adhesive tape 208, and when the control unit 100 receives the machining operation start instruction of the operator from the input unit, the laser machining device 1 starts the machining operation according to the registered machining content information.

[0062] In the machining operation, the laser machining device 1 holds the workpiece 200 on the holding surface 11 of the chuck table 10 by suction through the adhesive tape 208, and clamps the annular frame 210 with the clamp section 12. Next, the movement unit 30 moves the chuck table 10 toward the lower side of the photographing unit 40, and the photographing unit 40 photographs the workpiece 200. The laser machining device 1 performs alignment according to the image obtained by the photographing of the photographing unit 40.

[0063] The laser processing apparatus 1 moves the laser beam irradiation unit 20 and the workpiece 200 along the division predetermined line 203 relative to each other by the moving unit 30 according to the processing content information, and irradiates the division predetermined line 203 with the pulsed laser beam 21 from the laser beam irradiation unit 20. In Embodiment 1, as shown in FIG. 3, the laser processing apparatus 1 sets the focal point 211 of the laser beam 21 inside the substrate 201 of the workpiece 200, and irradiates the division predetermined line 203 with the laser beam 21, thereby forming a modified layer inside the substrate 201 along the division predetermined line 203. When the modified layer is formed inside the substrate 201 along all of the division predetermined lines 203, the laser processing apparatus 1 stops the irradiation of the laser beam 21, and ends the processing operation. Figure 2

[0064] In the processing operation, the laser processing apparatus 1 moves the laser beam irradiation unit 20 relative to the chuck table 10 along the X-axis direction above each division predetermined line 203 while maintaining the position of the focal point 211 in the Z-axis direction, and moves the laser beam irradiation unit 20 relative to the chuck table 10 along the Y-axis direction at a position that is a prescribed distance from the outer periphery side of the end portion of each division predetermined line 203. In the processing operation, the laser processing apparatus 1 irradiates the laser beam 21 at the position shown by the solid line 300 in FIG. 3 while moving the laser beam irradiation unit 20 relative to the chuck table 10 above the workpiece 200, and stops the irradiation of the laser beam 21 at the position shown by the dashed line 301 in FIG. 3 while moving the laser beam irradiation unit 20 relative to the chuck table 10 above the workpiece 200. Figure 4 Figure 4

[0065] In the processing operation, the laser processing apparatus 1 irradiates the laser beam 21 at the division predetermined line 203 that is calculated by the moving control section 103 to be parallel to the light receiving section 51 of the output measurement unit 50 in the X-axis direction or the division predetermined line 203 that is closest to the center of the light receiving section 51 in the Y-axis direction, moves the laser beam irradiation unit 20 relative to the light receiving section 51 of the output measurement unit 50 along the X-axis direction to above the light receiving section 51 of the output measurement unit 50, irradiates the laser beam 21 from the laser beam irradiation unit 20 above the light receiving section 51 of the output measurement unit 50, and moves the laser beam irradiation unit 20 relative to the light receiving section 51 of the output measurement unit 50 along the Y-axis direction at a position above the center of the light receiving section 51 of the output measurement unit 50. Figure 4 Figure 5 In the processing operation, the laser processing apparatus 1 irradiates the laser beam 21 at the division predetermined line 203 that is calculated by the moving control section 103 to be parallel to the light receiving section 51 of the output measurement unit 50 in the X-axis direction or the division predetermined line 203 that is closest to the center of the light receiving section 51 in the Y-axis direction, moves the laser beam irradiation unit 20 relative to the light receiving section 51 of the output measurement unit 50 along the X-axis direction to above the light receiving section 51 of the output measurement unit 50, irradiates the laser beam 21 from the laser beam irradiation unit 20 above the light receiving section 51 of the output measurement unit 50, and moves the laser beam irradiation unit 20 relative to the light receiving section 51 of the output measurement unit 50 along the Y-axis direction at a position above the center of the light receiving section 51 of the output measurement unit 50.

[0066] ​​​​In the laser processing apparatus 1, the light receiving portion 51 of the output measuring unit 50 receives the laser beam 21, and outputs an electric signal corresponding to the output of the laser beam 21 to the control unit 100. In addition, in Embodiment 1, the light receiving portion 51 of the output measuring unit 50 is disposed at a position that is a prescribed distance below the condensing point 211, and thus receives the laser beam 21 that diverges beyond the condensing point 211.

[0067] The prediction portion 102 of the control unit 100 of the laser processing apparatus 1 converts the electric signal from the light receiving portion 51 that starts to receive light at the predicted time 54 to the pre-equilibrium output 55 of the laser beam 21, and predicts the equilibrium output 52 from the converted pre-equilibrium output 55 of the laser beam 21 and with reference to the data 104 stored in the storage portion 101, as shown by the solid line in FIG. 6. Figure 3

[0068] As described above, in the laser processing apparatus 1 of Embodiment 1, the output measuring unit 50 is disposed at a position where the position of the laser beam 21 after passing through the condensing lens 23 can be measured, and the control unit 100 has a prediction portion 102 that predicts the equilibrium output 52 of the laser beam 21 from the pre-equilibrium output 55 of the laser beam 21 at the predicted time 54 that is shorter than the prescribed time 53 required for the output of the laser beam 21 to stabilize based on the data 104 stored in the storage portion 101, and thus the equilibrium output 52 can be found at the predicted time 54 that is shorter than the prescribed time 53. As a result, the laser processing apparatus 1 achieves the effect of being able to accurately measure the equilibrium output 52 of the laser beam 21 after passing through the condensing lens 23 without reducing productivity.

[0069] In addition, the laser processing apparatus 1 also has a movement control portion 103 that controls the movement distance of the X-axis movement unit 31 so that the laser beam 21 passes above the workpiece 200 held on the chuck table 10 and the light receiving portion 51 of the output measuring unit 50 when the control unit 100 is processing the workpiece 200, and thus the light receiving portion 51 of the output measuring unit 50 can be irradiated with the laser beam 21 that has passed through the condensing lens 23 during the processing operation.

[0070] In addition, in the laser processing apparatus 1, the movement control portion 103 moves the laser beam irradiation unit 20 in the Y-axis direction so as to be relatively above the center of the light receiving portion 51 of the output measuring unit 50, and thus the laser beam irradiation unit 20 is relatively instantaneously stopped above the center of the light receiving portion 51 with respect to the output measuring unit 50, and the laser beam 21 at the predicted time 54 can be irradiated to the light receiving portion 51 without stopping the processing operation.

[0071] ​Further, in the laser processing apparatus 1, when the laser beam 21 is irradiated to the division predetermined line 203 parallel to the light-receiving part 51 of the output measuring unit 50 in the X-axis direction or the division predetermined line 203 closest to the center of the Y-axis direction of the light-receiving part 51, the laser beam irradiation unit 20 is relatively moved to the upper side of the light-receiving part 51 with respect to the output measuring unit 50, and the laser beam 21 is irradiated to the light-receiving part 51. As a result, the laser processing apparatus 1 can suppress the time required for measurement of the output of the laser beam 21, and can improve the productivity.

[0072] Embodiment 2

[0073] A laser processing apparatus of Embodiment 2 of the present application will be described with reference to the drawings. Figure 6 is a perspective view showing an output measuring unit of the laser processing apparatus of Embodiment 2. Figure 7 is a view showing data stored in a storage section of a control unit of the laser processing apparatus of Embodiment 2. Further, in Figure 6 and Figure 7 , the same reference numerals are attached to the same parts as those of Embodiment 1, and the description thereof will be omitted.

[0074] The laser processing apparatus 1 of Embodiment 2 is the same as that of Embodiment 1 except that the output measuring unit 50 is housed in a housing 60 and provided on the second moving plate 16, and the laser processing apparatus 1 has a photodiode 70 provided in the housing 60, and the data 104-2 (shown in Figure 7 ) stored in the storage section 101 is different.

[0075] As shown in Figure 6 , the housing 60 is formed in a box shape provided at a position overlapping the light-receiving part 51 in the Z-axis direction and provided with an opening 61 through which the laser beam 21 passes. The photodiode 70 is housed in the housing 60 and has a light-receiving part 71 that receives scattered light 212 of the laser beam 21 scattered by the light-receiving part 51. The photodiode 70 converts the scattered light 212 of the laser beam 21 into an electric signal corresponding to the light amount, and outputs the converted electric signal to the control unit 100. Since the photodiode 70 converts the scattered light 212 of the laser beam 21 received by the light-receiving part 71 into an electric signal corresponding to the light amount, and outputs the converted electric signal to the control unit 100, the time required for measurement is short (the response speed is fast) compared to the output measuring unit 50 that is a power meter that heats the light-receiving part 51 by the laser beam 21 and converts heat of the light-receiving part 51 into an electric signal. Further, in the present application, the position where the photodiode 70 is provided is not limited to the position shown in Figure 6 , and for example, can be provided in the jig part 12.

[0076] The control unit 100 converts the electric signal from the photodiode 70 into the output of the laser beam 21 of the scattered light 212. As shown in FIG. 6, the data 104-2 stored in the storage section 101 of the control unit 100 is the correlation data of the actual balance output 52 of the laser beam 21 measured by the output measurement unit 50 of the power meter that has received the laser beam 21 by the light receiving section 51 and the output of the laser beam 21 of the scattered light 212 measured by the photodiode 70. Figure 7

[0077] In addition, the horizontal axis of the graph shown in FIG. 6 indicates the output of the laser beam 21 of the scattered light 212 obtained by converting the electric signal from the photodiode 70, and the vertical axis thereof indicates the balance output 52 of the laser beam 21 obtained by converting the electric signal from the output measurement unit 50 of the power meter that has received the laser beam 21 by the light receiving section 51. Thus, the data 104-2 shown in FIG. 6 is the correlation of the output of the laser beam 21 of the scattered light 212 received by the light receiving section 71 of the photodiode 70 and the balance output 52 of the laser beam 21 received by the light receiving section 51 of the output measurement unit 50. Figure 7 Figure 7 Figure 7

[0078] The prediction section 102 of the control unit 100 according to Embodiment 2 calculates the actual balance output 52 of the laser beam 21 from the output of the laser beam 21 of the scattered light 212 based on the data 104-2 stored in the storage section 101. Specifically, the prediction section 102 calculates the balance output 52 corresponding to the output of the laser beam 21 of the scattered light 212 obtained by converting the electric signal from the photodiode 70 from the data 104-2, and calculates the calculated balance output 52 as the actual balance output 52 of the laser beam 21.

[0079] In the laser processing apparatus 1 according to Embodiment 2, the output measurement unit 50 is disposed so as to be able to measure the position of the laser beam 21 after passing through the condenser lens 23, has the photodiode 70 that receives the scattered light 212 of the laser beam 21 scattered by the light receiving section 51, and the control unit 100 has the prediction section 102 that predicts the balance output 52 of the laser beam 21 from the output of the laser beam 21 of the scattered light 212 received by the photodiode 70 based on the data 104-2 stored by the storage section 101, and thus is able to obtain the balance output 52 in a shorter time than the prescribed time 53. As a result, the laser processing apparatus 1 is able to measure the balance output 52 of the laser beam 21 after passing through the condenser lens 23 without reducing the productivity, and is able to suppress the time required for the measurement of the balance output 52.

[0080] ​​​​In addition, the present application is not limited to the above-described embodiments. That is, various modifications can be made within the scope of the gist of the present application to implement the present application. For example, in the present application, a moving unit that moves the output measurement unit 50 in the Y-axis direction on the second moving plate 16 can be provided, and the laser beam 21 can be irradiated to the light receiving portion 51 of the output measurement unit 50 at any timing before and after the laser beam 21 is irradiated to all of the division predetermined lines 203. In this case, the laser beam 21 can be irradiated to the light receiving portion 51 of the output measurement unit 50 at any timing before and after the laser beam 21 is irradiated to all of the division predetermined lines 203, or the laser beam 21 can be irradiated to the light receiving portion 51 of the output measurement unit 50 at any timing before and after the laser beam 21 is irradiated to at least one of the division predetermined lines 203 among all of the division predetermined lines 203.

Claims

1. A laser processing device, characterized in that: The laser processing device comprises: A chuck table that 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 for processing and feeding the chuck table relative to the laser beam irradiation unit; An indexing feeding unit for indexing and feeding the chuck table relative to the laser beam irradiation unit; an output measuring unit that measures the output of the laser beam; and A control unit that controls each component. The laser beam irradiation unit comprises: laser oscillator; and a condensing lens for converging the laser beam oscillated from the laser oscillator and irradiating the workpiece; The output measurement unit is arranged at a position where the laser beam passing through the focusing lens can be measured. The control unit has: a storage unit that stores, as data, a time from when the laser beam is irradiated to the output measuring unit and a change in output accompanying the change in the time; and a prediction unit that predicts, based on the data stored in the storage unit, the output of the laser beam when it stabilizes and when the output of the laser beam does not change, from the output of the laser beam for a time shorter than the time required for the output to stabilize; The output measurement unit is arranged adjacent to the chuck table, The control unit also has a movement control unit, which controls the movement distance of the processing feed unit when processing the workpiece so that the laser beam passes through the workpiece held by the chuck worktable and the light receiving part of the output measuring unit. The light receiving part is arranged at a position that is a specified distance away from a focal point set inside the workpiece held by the chuck worktable in the vertical direction.

2. A laser processing device, characterized in that: The laser processing device comprises: A chuck table that 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 for processing and feeding the chuck table relative to the laser beam irradiation unit; An indexing feeding unit for indexing and feeding the chuck table relative to the laser beam irradiation unit; an output measuring unit that measures the output of the laser beam; and A control unit that controls each component. The laser beam irradiation unit comprises: laser oscillator; and a condensing lens for converging the laser beam oscillated from the laser oscillator and irradiating the workpiece; The output measurement unit contains: a power meter disposed at a position capable of measuring the laser beam after passing through the condenser lens and having a light receiving portion for directly receiving the laser beam; as well as a photodiode having a light receiving portion for receiving scattered light of the laser beam, The control unit has: a storage unit that stores correlation data between the actual output of the laser beam measured by the power meter and the output of the laser beam of scattered light measured by the photodiode; and The prediction unit calculates the actual output of the laser beam from the output of the scattered light laser beam based on the correlation data stored in the storage unit.

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