Laser processing equipment

Abstract

To provide a laser processing device capable of performing high accuracy processing while reducing downtime.SOLUTION: A laser processing device 1 includes: a laser beam irradiation unit 20 that irradiates a workpiece 200 with a laser beam 21; a control unit 100; and a plasma imaging unit having a reference line in an imaging area and imaging a plasma generated at light collection point of the laser beam 21. The control unit 100 includes: a storage section 101 that stores a first coordinate positional relationship at a design stage between a plasma and the reference line; a determination section 102 that determines whether or not there is a difference between the first coordinate positional relationship and a first actual coordinate positional relationship between the plasma and the reference line obtained by actual measurement; and an adjustment instruction section 103 that, when it is determined that there is a difference, makes an adjustment such that the plasma is positioned at the same position as the first coordinate positional relationship.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In order to divide a semiconductor wafer into chips, a method is known in which a laser processing device is used to cut the wafer by irradiating it with a laser beam along streets set on the wafer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-320466 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned laser processing apparatus, processing is performed by positioning the reference line of the microscope of the imaging unit mounted on the apparatus at the center of the street, and the target pattern on the wafer, the distance from the target pattern to the center of the street, etc. are registered in advance in the apparatus's controller. Then, the registered target pattern is detected, the street is detected based on the distance from the registered target pattern, alignment is performed, and processing is automatically performed by feeding the focal point of the laser beam relative to the detected street.

[0005] In such laser processing equipment, a further step (hairline alignment) is performed to align the reference line of the microscope of the imaging unit mounted on the equipment with the center line of the groove formed by the laser beam. Specifically, this hairline alignment step involves first irradiating the surface of the wafer with a laser beam to form a groove, then imaging the groove and processing the image to detect the center of the groove, calculating the amount and direction of deviation between the center position of this groove and the reference line position of the microscope, and adding or subtracting this amount and direction of deviation to the coordinate position, thereby aligning the center position of the groove with the reference line position of the microscope, and storing the position where the center position of the groove and the reference line position of the microscope are aligned as the origin position in the equipment's controller.

[0006] However, the actual relative coordinate positional relationship between the focal point and the microscope's reference line changes subtly over time due to factors such as ambient temperature conditions. More specifically, the optical axis of the laser beam shifts due to factors such as oscillator pointing changes and mirror position shifts, resulting in a positional shift between the focal point and the reference line. Therefore, if processing is performed based on the relative coordinate positional relationship determined at the design stage, processing accuracy will decrease.

[0007] For this reason, when performing high-precision cutting on wafers, it is necessary to use an adjustment wafer each time to process and observe the wafer and align the hairline, which not only requires more labor but also increases the equipment's downtime, resulting in reduced productivity.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser processing apparatus that is capable of performing high-precision processing while reducing downtime. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, the laser processing apparatus of the present invention is a laser processing apparatus comprising a holding table for holding a workpiece, a laser beam irradiation unit for irradiating a laser beam onto the workpiece held on the holding table, and a control unit for controlling each component, and has a plasma imaging unit having a reference line within an imaging area and imaging plasma generated at a focal point of the laser beam, and the laser beam irradiation unit comprises a laser oscillator, a condenser for condensing the laser beam emitted from the laser oscillator and irradiating it onto the workpiece, a first mirror disposed between the laser oscillator and the condenser for reflecting the laser beam and changing the traveling direction, and a control unit for controlling the laser beam incident on the first mirror. and a first actuator that operates the first mirror to change the emission angle of the laser beam incident on the first mirror, wherein the control unit includes a memory section that stores a first coordinate positional relationship, which is the relative coordinate positional relationship at the design stage between the plasma generated at the focal point and a reference line of the plasma imaging unit, a determination section that determines whether or not there is a difference between the first coordinate positional relationship and a first actual coordinate positional relationship, which is the relative coordinate positional relationship between the plasma and the reference line obtained by actual measurement, and an adjustment instruction section that, when the determination section determines that there is a difference, operates the first actuator to change the emission angle of the laser beam incident on the first mirror, thereby making an adjustment so that the plasma is positioned at the same position as in the first coordinate positional relationship.

[0010] In the laser processing apparatus, the laser beam irradiation unit is disposed between the laser oscillator and the condenser, and includes a second mirror that reflects the laser beam to change its traveling direction, and a second actuator that operates the second mirror to change the emission angle of the laser beam that has entered the second mirror, and further includes an effusion light imaging unit that has a reference line within an imaging area and images effusion light of the laser beam that has passed through the second mirror without being reflected by it, and the memory unit stores a second coordinate positional relationship between the effusion light and the reference line of the effusion light imaging unit at the design stage. The coordinate position relationship may be further stored, and the determination unit may further determine whether or not there is a difference between the second coordinate position relationship and a second actual coordinate position relationship, which is a relative coordinate position relationship between the stray light obtained by actual measurement and a reference line of the stray light imaging unit, and when the determination unit determines that there is a difference, the adjustment instruction unit may operate at least one of the first actuator and the second actuator to adjust the optical path of the laser beam so that the plasma is positioned at the same position as in the first coordinate position relationship and the stray light is positioned at the same position as in the second coordinate position relationship. [Effects of the Invention]

[0011] The present invention has the effect of enabling high-precision machining while reducing downtime. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a laser processing device according to the first embodiment. [Figure 2] FIG. 2 is a diagram schematically showing the configuration of the laser beam irradiation unit of the laser processing apparatus shown in FIG. [Figure 3] FIG. 3 is a diagram showing an example of an image captured by the plasma imaging unit of the laser processing apparatus shown in FIG. [Figure 4] FIG. 4 is a diagram showing another example of an image captured by the plasma imaging unit of the laser processing apparatus shown in FIG. [Figure 5]FIG. 5 is a diagram schematically showing the configuration of a laser beam irradiation unit of a laser processing apparatus according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing an example of an image captured by the through-light imaging unit of the laser processing apparatus according to the second embodiment. [Figure 7] FIG. 7 is a diagram showing another example of an image captured by the through-light imaging unit of the laser processing apparatus according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0014] [Embodiment 1] A laser processing apparatus according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of the configuration of the laser processing apparatus according to the first embodiment. The laser processing apparatus 1 according to the first embodiment shown in Fig. 1 is a processing apparatus that irradiates a workpiece 200 with a laser beam 21.

[0015] (Workpiece) A workpiece 200 to be processed by the laser processing apparatus 1 according to the first embodiment is a wafer such as a disk-shaped semiconductor wafer or an optical device wafer, which has silicon, sapphire, gallium, or the like as a substrate 201. As shown in Fig. 1, the workpiece 200 has a surface 202 on which a plurality of mutually intersecting planned dividing lines 203 are set, and devices 204 are formed in areas defined by the planned dividing lines 203.

[0016] The device 204 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), or a memory (semiconductor storage device).

[0017] 1, the workpiece 200 is in the shape of a disk having a diameter larger than the outer diameter of the workpiece 200, and has an adhesive tape 209 attached to its outer edge with an annular frame 210 attached to a back surface 205 behind a front surface 202, and is supported within an opening in the annular frame 210. The workpiece 200 is divided into individual devices 204 by, for example, irradiating a laser beam 21 along planned division lines 203.

[0018] 1 is a processing device that performs ablation processing on the workpiece 200 by setting a focal point 211 of a pulsed laser beam 21 having a wavelength that is absorbable by a substrate 201 that constitutes the workpiece 200 from a surface 202 of the workpiece 200 to the surface 202, and irradiating the laser beam 21 along planned division lines 203. Note that in the present invention, the laser processing device 1 may also irradiate the pulsed laser beam 21 having a wavelength that is transparent to the substrate 201 of the workpiece 200.

[0019] As shown in FIG. 1, the laser processing device 1 includes a holding table 10 that holds a workpiece 200, a laser beam irradiation unit 20, a moving unit 30, an imaging unit 40, and a control unit 100.

[0020] The holding table 10 holds the workpiece 200 on a holding surface 11 that is parallel to the horizontal direction. The holding surface 11 is disk-shaped and made of porous ceramic or the like, and is connected to a vacuum suction source (not shown) via a suction path (not shown). The holding table 10 is sucked by the vacuum suction source to suction-hold the workpiece 200 placed on the holding surface 11. A plurality of clamps 12 are arranged around the holding table 10 to clamp an annular frame 210 that supports the workpiece 200 in an opening.

[0021] Furthermore, the holding table 10 is rotated by the rotational movement unit 33 of the movement unit 30 about an axis that is perpendicular to the holding surface 11 and parallel to the Z-axis direction that is parallel to the vertical direction. The holding table 10, together with the rotational movement unit 33, is moved by the X-axis movement unit 31 of the movement unit 30 in the X-axis direction (corresponding to the machining proceeding direction) that is parallel to the horizontal direction, and is moved by the Y-axis movement unit 32 in the Y-axis direction that is parallel to the horizontal direction and perpendicular to the X-axis direction. The holding table 10 is moved by the movement unit 30 between a machining area below the laser beam irradiation unit 20 and a carry-in / out area that is away from below the laser beam irradiation unit 20 and where the workpiece 200 is carried in and out.

[0022] The moving unit 30 relatively moves the holding table 10 and the focal point 211 of the laser beam 21 irradiated by the laser beam irradiation unit 20 in the X-axis direction, the Y-axis direction, the Z-axis direction, and around an axis parallel to the Z-axis direction. The X-axis direction and the Y-axis direction are perpendicular to each other and parallel to the holding surface 11 (i.e., the horizontal direction). The Z-axis direction is perpendicular to both the X-axis direction and the Y-axis direction.

[0023] The moving unit 30 includes an X-axis moving unit 31 which is a processing feed unit that moves the holding table 10 in the X-axis direction, a Y-axis moving unit 32 which is an indexing feed unit that moves the holding table 10 in the Y-axis direction, a rotational moving unit 33 that rotates the holding table 10 around an axis parallel to the Z-axis direction, and a Z-axis moving unit 34 that moves the focal point 211 of the laser beam 21 of the laser beam irradiation unit 20 in the Z-axis direction.

[0024] The Y-axis moving unit 32 is an indexing feed unit that moves the holding table 10 and the focal point 211 of the laser beam 21 of the laser beam irradiation unit 20 relatively in the Y-axis direction. In the first embodiment, the Y-axis moving unit 32 is installed on the device body 2 of the laser processing device 1. The Y-axis moving unit 32 supports the moving plate 5 that supports the X-axis moving unit 31 so that the moving plate 5 is movable in the Y-axis direction.

[0025] The X-axis moving unit 31 is a processing feed unit that moves the holding table 10 and the focal point 211 of the laser beam 21 of the laser beam irradiation unit 20 relatively in the X-axis direction. The X-axis moving unit 31 is installed on the moving plate 5. The X-axis moving unit 31 supports a second moving plate 6 that supports a rotational moving unit 33 that rotates the holding table 10 around an axis parallel to the Z-axis direction, so that the second moving plate 6 can move freely in the X-axis direction. The second moving plate 6 supports the rotational moving unit 33 and the holding table 10. The rotational moving unit 33 supports the holding table 10.

[0026] The Z-axis moving unit 34 is a feed unit that moves the holding table 10 and the focal point 211 of the laser beam 21 of the laser beam irradiation unit 20 relatively in the Z-axis direction. The Z-axis moving unit 34 is installed on an upright wall 3 that stands upright from the apparatus main body 2. The Z-axis moving unit 34 supports a support column 4, the tip of which is located a part including a condenser lens 23 (described later) of the laser beam irradiation unit 20, so as to be movable in the Z-axis direction.

[0027] The X-axis moving unit 31, the Y-axis moving unit 32, and the Z-axis moving unit 34 are each provided with a well-known ball screw that is rotatable about its axis and that moves the moving plates 5, 6 or the support column 4 in the X-axis, Y-axis, or Z-axis direction when rotated about its axis, a well-known pulse motor that rotates the ball screw about its axis, and a well-known guide rail that supports the moving plates 5, 6 or the support column 4 so that they are movably in the X-axis, Y-axis, or Z-axis direction. The rotational moving unit 33 is provided with a motor that rotates the holding table 10 about its axis, etc.

[0028] The laser processing device 1 also includes an X-axis position detection unit (not shown) for detecting the position of the holding table 10 in the X-axis direction, a Y-axis position detection unit (not shown) for detecting the position of the holding table 10 in the Y-axis direction, and a Z-axis position detection unit (not shown) for detecting the position of the support column 4 in the Z-axis direction. Each position detection unit outputs the detection result to the control unit 100.

[0029] Next, we will explain the laser beam irradiation unit 20 of the laser processing apparatus 1. Figure 2 is a diagram schematically showing the configuration of the laser beam irradiation unit of the laser processing apparatus shown in Figure 1. Note that Figure 2 omits the clamp unit 12.

[0030] The laser beam irradiation unit 20 is a laser beam irradiation means that focuses and irradiates a pulsed laser beam 21 onto a workpiece 200 held on the holding surface 11 of the holding table 10. In the first embodiment, a part of the laser beam irradiation unit 20 is disposed at the tip of a support column 4 that is supported by a Z-axis moving unit 34 that is installed on an upright wall 3 that stands upright from the apparatus main body 2, as shown in FIG.

[0031] The laser beam irradiation unit 20 irradiates a laser beam 21 having a wavelength that is absorbed by the substrate 201 of the workpiece 200 held on the holding table 10. As shown in FIG. 2 , the laser beam irradiation unit 20 includes a laser oscillator 22 that emits a pulsed laser beam 21, and a condenser lens 23 that is a condenser that condenses the laser beam 21 emitted from the laser oscillator 22 and irradiates the workpiece 200 with the laser beam 21.

[0032] In addition, in embodiment 1, the laser beam irradiation unit 20 is arranged between the laser oscillator 22 and the focusing lens 23 and includes a first mirror 24 that reflects the laser beam 21 emitted from the laser oscillator 22 and changes the direction of travel, and a first actuator 25 that operates the first mirror 24 to change the emission angle of the laser beam 21 incident on the first mirror 24.

[0033] The condensing lens 23 is disposed at a position opposite to the holding surface 11 of the holding table 10 in the Z-axis direction. The condensing lens 23 is a focusing optical element that focuses and irradiates the pulsed laser beam 21 onto the workpiece 200 held on the holding table 10. The condensing lens 23 transmits the laser beam 21 that is emitted from the laser oscillator 22 and reflected by the first mirror 24, and focuses the laser beam 21 at a focusing point 211. In the first embodiment, the condensing lens 23 focuses the focusing point 211 of the laser beam 21 on the surface 202 of the workpiece 200 held on the holding surface 11 of the holding table 10.

[0034] In the first embodiment, the first mirror 24 has a reflecting surface 241 that reflects the laser beam 21. The first mirror 24 reflects the laser beam 21 at the reflecting surface 241 toward the condenser lens 23.

[0035] When driven, the first actuator 25 changes the orientation of the reflecting surface 241 of the first mirror 24. In the first embodiment, a pair of first actuators 25 are attached to the first mirror 24. One of the first actuators 25 (hereinafter, denoted by reference numeral 251) changes the orientation of the reflecting surface 241 of the first mirror 24 so as to change the orientation of the laser beam 21 reflected by the reflecting surface 241 of the first mirror 24 in the X-axis direction. The other first actuator 25 (hereinafter, denoted by reference numeral 252) changes the orientation of the reflecting surface 241 of the first mirror 24 so as to change the orientation of the laser beam 21 reflected by the reflecting surface 241 of the first mirror 24 in the Y-axis direction.

[0036] The laser beam irradiation unit 20 irradiates the workpiece 200 held on the holding table 10 with a laser beam 21 having a wavelength that is absorbed by a substrate 201 of the workpiece 200, thereby performing ablation processing on the workpiece 200. At the focal point 211, the laser beam 21 raises the temperature of the atmosphere surrounding the focal point 211, ionizes electrons and the like from atoms of molecules in the atmosphere surrounding the focal point 211, and generates a gas containing charged particles generated by the ionization, i.e., plasma 21-1. In the first embodiment, the plasma 21-1 is plasma generated in the gas surrounding the focal point 211 when the focal point 211 of the laser beam 21, which has an intensity equal to or greater than a predetermined value, is positioned in the gas.

[0037] The laser beam irradiation unit 20 also includes a dichroic mirror 26 disposed between the first mirror 24 and the condenser lens 23. The dichroic mirror 26 transmits the laser beam 21 reflected by the first mirror 24 toward the condenser lens 23. The dichroic mirror 26 reflects plasma 21-1 generated at a focal point 211 of the laser beam 21 incident through the condenser lens 23.

[0038] The laser processing apparatus 1 also includes a plasma imaging unit 50 shown in Fig. 2. Next, the plasma imaging unit 50 will be described. Fig. 3 is a diagram showing an example of an image captured by the plasma imaging unit of the laser processing apparatus shown in Fig. 1. Fig. 4 is a diagram showing another example of an image captured by the plasma imaging unit of the laser processing apparatus shown in Fig. 1.

[0039] Plasma imaging unit 50 is an imaging device that images plasma 21-1 reflected by dichroic mirror 26. In embodiment 1, plasma imaging unit 50 images plasma 21-1 that is reflected in turn by dichroic mirror 26 and mirror 52. Plasma imaging unit 50 includes a plurality of imaging elements, such as CCD (Charge Coupled Device) imaging elements or CMOS (Complementary MOS) imaging elements, that can receive light from plasma 21-1 and the like and capture images.

[0040] In the first embodiment, the plasma imaging unit 50 has a reference line 51 shown in Figures 3 and 4 that is arranged at a predetermined position within the imaging area. The imaging area is an area on a plane that is parallel to both the X-axis direction and the Y-axis direction and that can be imaged by the plasma imaging unit 50. In the captured image 500 captured and acquired by the plasma imaging unit 50, the reference line 51 is set at a predetermined position, as shown in Figures 3 and 4.

[0041] In the first embodiment, the captured image 500 captured by the plasma imaging unit 50, i.e., the imaging area of ​​the plasma imaging unit 50, is rectangular with its longitudinal direction parallel to the X-axis direction and its lateral direction parallel to the Y-axis direction. In the first embodiment, the plasma imaging unit 50 has, as reference lines 51 within the captured image 500, i.e., the imaging area, a first reference line 511 located at the center of the Y-axis direction of the captured image 500, i.e., the imaging area, and parallel to the X-axis direction, and a second reference line 512 located at the center of the X-axis direction of the captured image 500, i.e., the imaging area, and parallel to the Y-axis direction. Note that the reference lines 511 and 512 are imaginary lines within the captured image 500, i.e., the imaging area, and do not actually exist.

[0042] The imaging unit 40 captures an image of the workpiece 200 held on the holding table 10. The imaging unit 40 includes an imaging element such as a CCD (Charge Coupled Device) imaging element or a CMOS (Complementary MOS) imaging element that captures an image of an object facing the objective lens in the Z-axis direction. In the first embodiment, as shown in FIG. 1, the imaging unit 40 is disposed at the tip of the support column 4, and the objective lens is disposed at a position aligned with the condenser lens 23 along the X-axis direction.

[0043] The imaging unit 40 acquires the image captured by the imaging element and outputs the acquired image to the control unit 100. The imaging unit 40 also captures an image of the workpiece 200 held on the holding surface 11 of the holding table 10 and acquires an image for performing alignment between the workpiece 200 and the laser beam irradiation unit 20.

[0044] The laser processing apparatus 1 also includes an output measuring unit 60 shown in Fig. 1. In the first embodiment, the output measuring unit 60 is attached to the tip of a support 62 attached to the outer periphery of the holding table 10, and is disposed on the outer periphery of the holding table 10. The output measuring unit 60 moves in the X-axis direction and the Y-axis direction together with the holding table 10, and rotates around its axis. In the present invention, the output measuring unit 60 may be installed on the second moving plate 6.

[0045] In the first embodiment, the output measuring unit 60 has a light receiving surface 61 that receives the laser beam 21, and outputs information according to the output of the laser beam 21 received by the light receiving surface 61 to the control unit 100. The output measuring unit 60 is configured by, for example, a power meter that measures the output of the laser beam 21.

[0046] The control unit 100 controls each of the above-mentioned components of the laser processing apparatus 1, causing the laser processing apparatus 1 to perform processing operations on the workpiece 200. The control unit 100 is a computer having an arithmetic processing device with a microprocessor such as a CPU (central processing unit), a storage device with memory such as a ROM (read only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing device of the control unit 100 performs arithmetic processing in accordance with a computer program stored in the storage device, and outputs control signals for controlling the laser processing apparatus 1 to the above-mentioned components of the laser processing apparatus 1 via the input / output interface device, thereby realizing the functions of the control unit 100.

[0047] The laser processing device 1 also includes a display unit 110, which is a display means configured with a liquid crystal display device or the like that displays the status of the processing operation, images, etc., and an input unit, which is an input means used by the operator to input processing conditions, etc. The display unit 110 and the input unit are connected to the control unit 100. The input unit is configured with at least one of a touch panel provided on the display unit 110 and an external input device such as a keyboard.

[0048] As shown in FIG. 1, the control unit 100 includes a storage unit 101, a determination unit 102, and an adjustment instruction unit 103.

[0049] The storage unit 101 stores a first coordinate positional relationship, which is the relative coordinate positional relationship at the design stage of the laser processing apparatus 1, between the plasma 21-1 generated at the focal point 211 and the reference lines 511, 512 in the imaging area of ​​the plasma imaging unit 50. In the first embodiment, the storage unit 101 stores, as the first coordinate positional relationship, information that both the distance 514 (shown in FIG. 4) in the X-axis direction and the distance 515 (shown in FIG. 4) in the Y-axis direction between the intersection 513 of the reference lines 511, 512 of the captured image 500, which is the imaging area of ​​the plasma imaging unit 50, and the center 212 of the plasma 21-1 are zero. That is, in the first embodiment, the captured image 500 shown in Fig. 3 shows the plasma 21-1 and the reference lines 511 and 512 in the imaging area of ​​the plasma imaging unit 50, which satisfy the first coordinate positional relationship stored in the memory unit 101, because the intersection 513 of the reference lines 511 and 512 overlaps with the center 212 of the plasma 21-1. Note that in Figs. 3 and 4, the diameter of the plasma 21-1 is approximately 5 μm to 10 μm.

[0050] The determination unit 102 determines whether there is a difference between the first coordinate positional relationship stored in the memory unit 101 and a first actual coordinate positional relationship, which is the relative coordinate positional relationship between the plasma 21-1 and reference lines 511 and 512 in the captured image 500 obtained by the plasma imaging unit 50 capturing an image of the plasma 21-1 at a predetermined timing (corresponding to actual measurement). In the first embodiment, the determination unit 102 calculates, as the first actual coordinate positional relationship, both a distance 514 in the X-axis direction and a distance 515 in the Y-axis direction between the center 212 of the plasma 21-1 and an intersection 513 of the reference lines 511 and 512 in the captured image 500 obtained by the plasma imaging unit 50 capturing an image of the plasma 21-1 at a predetermined timing. In the first embodiment, the determination unit 102 calculates the sum of the calculated distance 514 in the X-axis direction and the distance 515 in the Y-axis direction, and determines whether the sum of the calculated distances 514 and 515 is equal to or greater than a predetermined value. In the present invention, the judgment unit 102 is not limited to judging whether the sum of the calculated distances 514, 515 is equal to or greater than a predetermined value, but may also judge whether each of the calculated distances 514, 515 is equal to or greater than a predetermined threshold value (predetermined value).

[0051] In the first embodiment, when the determination unit 102 determines that the sum of the calculated distances 514, 515 is equal to or greater than a predetermined value, the determination unit 102 determines that there is a discrepancy between the first coordinate positional relationship stored in the storage unit 101 and the first actual coordinate positional relationship. In the first embodiment, when the sum of the calculated distances 514, 515 is not equal to or greater than the predetermined value, i.e., is less than the predetermined value, the determination unit 102 determines that there is no discrepancy between the first coordinate positional relationship stored in the storage unit 101 and the first actual coordinate positional relationship. In this way, the determination unit 102 calculates the distances 514, 515 of the captured image 500 obtained by the plasma imaging unit 50 capturing the plasma 21-1 at a predetermined timing, and determines whether the sum of the distances 514, 515 is equal to or greater than a predetermined value, thereby determining whether there is a discrepancy between the first coordinate positional relationship stored in the storage unit 101 and the first actual coordinate positional relationship. In addition, when the judgment unit 102 determines whether each of the distances 514, 515 is equal to or greater than a predetermined threshold, if it determines that at least one of the distances 514, 515 is equal to or greater than the threshold, it preferably determines that there is a difference between the first coordinate positional relationship stored in the memory unit 101 and the first actual coordinate positional relationship, and if it determines that both of the distances 514, 515 are less than the threshold, it preferably determines that there is no difference between the first coordinate positional relationship stored in the memory unit 101 and the first actual coordinate positional relationship.

[0052] When the determination unit 102 determines that there is a difference between the first coordinate positional relationship stored in the memory unit 101 and the first actual coordinate positional relationship, the adjustment instruction unit 103 operates the first actuators 251 and 252 to change the emission angle from the first mirror 24 of the laser beam 21 incident on the first mirror 24, thereby adjusting the plasma 21-1 to be positioned at the same position as in the first coordinate positional relationship. In the first embodiment, when the determination unit 102 determines that there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship, the adjustment instruction unit 103 operates the first actuators 251 and 252 to change the orientation of the reflecting surface 241 of the first mirror 24 so that both distances 514 and 515, which are the first actual coordinate positional relationship, become zero.

[0053] The functions of the determination unit 102 and the adjustment instruction unit 103 are realized by the arithmetic processing unit performing arithmetic processing in accordance with a computer program stored in a storage device. The function of the storage unit 101 is realized by the above-mentioned storage device.

[0054] Next, the processing operation of the laser processing apparatus 1 configured as described above will be explained. In the laser processing apparatus 1, the control unit 100 receives and registers processing conditions input by an operator, and the workpiece 200 is placed on the holding surface 11 of the holding table 10 positioned in the carry-in / out area via adhesive tape 209. The laser processing apparatus 1 starts the processing operation when the control unit 100 receives an instruction to start the processing operation from the operator. In the laser processing apparatus 1, in the normal state, the center 212 of the plasma 21-1 is located at the intersection 513 of the reference lines 511 and 512 in the captured image 500 captured by the plasma imaging unit 50.

[0055] When the processing operation starts, the control unit 100 of the laser processing apparatus 1 sucks and holds the workpiece 200 on the holding surface 11 of the holding table 10 via the adhesive tape 209, and causes the clamp section 12 to clamp the annular frame 210. During the processing operation, the control unit 100 of the laser processing apparatus 1 controls the moving unit 30 to move the holding table 10 to the processing area, captures an image of the workpiece 200 sucked and held on the holding table 10 with the imaging unit 40 to obtain the image, and performs alignment to align the focal point 211 of the laser beam irradiation unit 20 with the planned division line 203.

[0056] In the processing operation, the control unit 100 of the laser processing apparatus 1 controls the Z-axis moving unit 34 to position the condenser lens 23 of the laser beam applying unit 20 at a position where the focal point 211 of the laser beam applying unit 20 becomes the surface 202 of the planned dividing line 203 of the workpiece 200. In the processing operation, the control unit 100 controls the moving unit 30 to relatively move the holding table 10 and the focal point 211 of the laser beam applying unit 20 along the planned dividing line 203, while irradiating the planned dividing line 203 of the workpiece 200 with the pulsed laser beam 21 from the surface 202 side of the substrate 201.

[0057] In the first embodiment, in the processing operation, the laser processing apparatus 1 performs ablation processing on the planned dividing lines 203 of the workpiece 200 to form recessed processed grooves from the surface 202, because the laser beam 21 has a wavelength that is absorbed by the substrate 201 of the workpiece 200. In the first embodiment, in the processing operation, when the laser processing apparatus 1 has irradiated the laser beam 21 along all of the planned dividing lines 203, it stops irradiating the laser beam 21 and moves the holding table 10 to the carry-in / out area. In the processing operation, the laser processing apparatus 1 positions the holding table 10 in the carry-in / out area, stops suction holding of the workpiece 200 on the holding table 10, and releases the clamping of the annular frame 210 of the clamp unit 12, thereby completing the processing operation.

[0058] Furthermore, in the laser processing apparatus 1, the laser beam 21 may deviate from its normal optical axis due to temperature changes caused by irradiation of the laser beam 21, changes over time, and the like, resulting in a misalignment of the processed groove. When the laser beam 21 deviates from its normal optical axis, the center 212 of the plasma 21-1 deviates from the intersection 513 of the reference lines 511 and 512 in the captured image 500 captured by the plasma imaging unit 50. For this reason, the laser processing apparatus 1 determines, at a predetermined timing, whether there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship using the determination unit 102 of the control unit 100. The predetermined timing is not particularly limited in the present invention and may be, for example, immediately after the start of the processing operation, at predetermined time intervals, after a predetermined number of workpieces 200 have been processed, or after a predetermined number of planned division lines 203 have been processed.

[0059] When the laser processing apparatus 1 determines whether there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship, the control unit 100 controls the moving unit 30 to position the condenser lens 23 of the laser beam irradiating unit 20 above the output measuring unit 60 at a position where a focal point 211 is formed between the condenser lens 23 and the light receiving surface 61 of the output measuring unit 60. In the laser processing apparatus 1, the control unit 100 controls the laser beam irradiating unit 20 to irradiate the laser beam 21 from the laser beam irradiating unit 20 to the output measuring unit 60 for a predetermined time, and causes the plasma imaging unit 50 to image the plasma 21-1 generated at the focal point 211.

[0060] In the laser processing apparatus 1, the control unit 100 acquires the captured image 500, and the determination unit 102 determines whether or not there is a difference between the first coordinate positional relationship stored in the memory unit 101 and the first actual coordinate positional relationship of the captured image 500. When the determination unit 102 of the control unit 100 determines that there is a difference between the first coordinate positional relationship stored in the memory unit 101 and the first actual coordinate positional relationship of the captured image 500, the adjustment instruction unit 103 operates the first actuators 251, 252 to change the orientation of the reflecting surface 241 of the first mirror 24 so that the plasma 21-1 is positioned at the same position as in the first coordinate positional relationship, that is, so that the center 212 of the plasma 21-1 is positioned at the intersection 513 of the reference lines 511, 512 of the captured image 500.

[0061] In this way, the laser processing device 1 positions the laser beam 21 at the correct optical axis position, suppresses positional deviation of the processed groove, and enables the processed groove to be formed at the correct position. In this way, the laser processing device 1 performs so-called hairline alignment, which positions the center 212 of the plasma 21-1 at the intersection 513 of the reference lines 511, 512 of the captured image 500, enabling the processed groove to be formed at the correct position.

[0062] The laser processing apparatus 1 returns to processing operations, etc. after the adjustment instruction unit 103 of the control unit 100 changes the orientation of the reflecting surface 241 of the first mirror 24, or after the judgment unit 102 determines that there is no difference between the first coordinate position relationship stored in the memory unit 101 and the first actual coordinate position relationship of the captured image 500.

[0063] As described above, the laser processing apparatus 1 according to the first embodiment images the plasma 21-1 with the plasma imaging unit 50 at a predetermined timing, determines whether there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship with the determination unit 102, and if there is a difference, adjusts the adjustment instruction unit 103 so that the plasma 21-1 is positioned at the same position as in the first coordinate positional relationship, thereby enabling so-called hairline alignment to be performed without irradiating the wafer for adjustment with the laser beam 21 to perform processing. As a result, the laser processing apparatus 1 can perform high-precision processing while reducing downtime.

[0064] Furthermore, the laser processing apparatus 1 adjusts the orientation of the reflecting surface 241 of the first mirror 24 of the laser beam irradiation unit 20 so that the center 212 of the plasma 21-1 is aligned with the intersection 513 of the reference lines 511, 512 of the plasma imaging unit 50, instead of aligning the hairline, which was conventionally performed by aligning the reference line of the imaging unit 40 with the processed groove. As a result, the laser processing apparatus 1 has the further advantage of being able to eliminate the cause of machine differences that occur between apparatuses.

[0065] [Embodiment 2] A laser processing apparatus according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a diagram schematically illustrating the configuration of a laser beam irradiation unit of the laser processing apparatus according to the second embodiment. FIG. 6 is a diagram illustrating an example of an image captured by the through-light imaging unit of the laser processing apparatus according to the second embodiment. FIG. 7 is a diagram illustrating another example of an image captured by the through-light imaging unit of the laser processing apparatus according to the second embodiment. In FIGS. 5, 6, and 7, the same parts as those in the first embodiment are designated by the same reference numerals, and their description will be omitted. In addition, in FIG. 5, the clamp unit 12 is omitted, as in FIG. 2.

[0066] The laser processing apparatus 1-2 according to the second embodiment is the same as the first embodiment except that it includes a light-receiving imaging unit 70, and that the configuration of the laser beam irradiation unit 20-2 and the function of the control unit 100 are different. As shown in Fig. 5, the laser beam irradiation unit 20-2 of the laser processing apparatus 1-2 according to the second embodiment includes a pair of second mirrors 27 and a second actuator 28 in addition to the configuration of the first embodiment.

[0067] The pair of second mirrors 27 are disposed between the laser oscillator 22 and the condenser lens 23, and reflect the laser beam 21 emitted from the laser oscillator 22 to change the traveling direction of the laser beam 21. Each of the pair of second mirrors 27 has a reflecting surface 271 that reflects the laser beam 21.

[0068] One of the second mirrors 27 (hereinafter, denoted by reference numeral 27-1) is disposed between the laser oscillator 22 and the first mirror 24. The one of the second mirrors 27-1 reflects the laser beam 21 emitted from the laser oscillator 22 toward the first mirror 24.

[0069] The other second mirror 27 (hereinafter, denoted by reference numeral 27-2) is disposed between the first mirror 24 and the dichroic mirror 26. The other second mirror 27-2 reflects the laser beam 21 incident from the first mirror 24 toward the dichroic mirror 26.

[0070] The second actuator 28 operates one of the second mirrors 27-1 in order to change the emission angle of the laser beam 21 incident on the one of the second mirrors 27-1. When the second actuator 28 is driven, it changes the orientation of the reflecting surface 271 of the second mirror 27-1.

[0071] In the second embodiment, a pair of second actuators 28 are attached to the second mirror 27-1. One of the second actuators 28 (hereinafter, designated by reference numeral 281) changes the orientation of the reflecting surface 271 of the second mirror 27-1 so as to change the orientation of the laser beam 21 reflected by the reflecting surface 271 of the second mirror 27-1 in the X-axis direction. The other second actuator 28 (hereinafter, designated by reference numeral 282) changes the orientation of the reflecting surface 271 of the second mirror 27-1 so as to change the orientation of the laser beam 21 reflected by the reflecting surface 271 of the second mirror 27-1 in the Y-axis direction.

[0072] In the second embodiment, the stray light imaging unit 70 provided in the laser processing apparatus 1-2 is an imaging device that images the stray light 21-2 of the laser beam 21 that is not reflected by the other second mirror 27-2 but is transmitted through the other second mirror 27-2. The stray light imaging unit 70 includes a plurality of imaging elements, such as CCD (Charge Coupled Device) imaging elements or CMOS (Complementary MOS) imaging elements, that can receive and image the stray light 21-2 of the laser beam 21.

[0073] In the second embodiment, the through-light imaging unit 70 has a reference line 71 shown in Figures 6 and 7 that is arranged at a predetermined position within the imaging area. The imaging area is an area on a plane that can be imaged by the through-light imaging unit 70. For this reason, the reference line 71 is set at a predetermined position in the captured image 700 captured and acquired by the through-light imaging unit 70, as shown in Figures 6 and 7.

[0074] In the second embodiment, the captured image 700 captured and acquired by the through-light imaging unit 70, i.e., the imaging area of ​​the through-light imaging unit 70, is rectangular. The longitudinal direction of the captured image 700 captured and acquired by the through-light imaging unit 70, i.e., the imaging area of ​​the through-light imaging unit 70, is parallel to the X-axis direction in a plane parallel to both the X-axis direction and the Y-axis direction, and the lateral direction is parallel to the Y-axis direction in the above-mentioned plane.

[0075] In the second embodiment, the through-light imaging unit 70 has, as reference lines 71 within the captured image 700, i.e., the imaging area, a first reference line 711 that is located at the center of the captured image 700, i.e., the imaging area, in the Y-axis direction and parallel to the X-axis direction, and a second reference line 712 that is located at the center of the captured image 700, i.e., the imaging area, in the X-axis direction and parallel to the Y-axis direction. Note that the reference lines 711 and 712 are imaginary lines within the captured image 700, i.e., the imaging area, and do not actually exist.

[0076] In addition to the first coordinate positional relationship described above, the storage unit 101 of the control unit 100 of the laser processing apparatus 1-2 according to the second embodiment stores a second coordinate positional relationship, which is a relative coordinate positional relationship at the design stage of the laser processing apparatus 1-2 between the through light 21-2 and reference lines 711, 712 in the imaging area of ​​the through light imaging unit 70. In the second embodiment, the storage unit 101 stores, as the second coordinate positional relationship, information that both a distance 714 (shown in FIG. 7 ) in the X-axis direction and a distance 715 (shown in FIG. 7 ) in the Y-axis direction between an intersection 713 of the reference lines 711, 712 in the captured image 700, which is the imaging area of ​​the through light imaging unit 70, and the center 213 of the through light 21-2 are zero. That is, in the first embodiment, the captured image 700 shown in Fig. 6 shows the stray light 21-2 and the reference lines 711, 712 in the imaging area of ​​the stray light imaging unit 70, which satisfy the second coordinate positional relationship stored in the storage unit 101, because the intersection 713 of the reference lines 711, 712 and the center 213 of the stray light 21-2 overlap. Note that in Figs. 6 and 7, the diameter of the stray light 21-2 is approximately 2 mm to 10 mm.

[0077] The determination unit 102 determines whether there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship, and also determines whether there is a difference between the second coordinate positional relationship stored in the storage unit 101 and a second actual coordinate positional relationship, which is the relative coordinate positional relationship between the stray light 21-2 and the reference lines 711, 712 in the captured image 700 obtained by the stray light imaging unit 70 capturing an image of the stray light 21-2 at a predetermined timing (corresponding to actual measurement). In the second embodiment, the determination unit 102 calculates, as the second actual coordinate positional relationship, both a distance 714 in the X-axis direction and a distance 715 in the Y-axis direction between an intersection 713 of the reference lines 711, 712 in the captured image 700 obtained by the stray light imaging unit 70 capturing an image of the stray light 21-2 at a predetermined timing and the center 213 of the stray light 21-2. In the second embodiment, the determination unit 102 calculates the sum of the calculated distance 714 in the X-axis direction and the calculated distance 715 in the Y-axis direction, and determines whether the sum of the calculated distances 714 and 715 is equal to or greater than a predetermined value.

[0078] In the second embodiment, if the determination unit 102 determines that the sum of the calculated distances 714, 715 is equal to or greater than a predetermined value, the determination unit 102 determines that there is a discrepancy between the second coordinate positional relationship stored in the storage unit 101 and the second actual coordinate positional relationship. In the second embodiment, if the sum of the calculated distances 714, 715 is not equal to or greater than the predetermined value, i.e., is less than the predetermined value, the determination unit 102 determines that there is no discrepancy between the second coordinate positional relationship stored in the storage unit 101 and the second actual coordinate positional relationship. In this way, the determination unit 102 calculates the distances 714, 715 of the captured image 700 obtained by the through-light imaging unit 70 capturing the through-light 21-2 at a predetermined timing, and determines whether the sum of the distances 714, 715 is equal to or greater than a predetermined value, thereby determining whether there is a discrepancy between the second coordinate positional relationship stored in the storage unit 101 and the second actual coordinate positional relationship.

[0079] When the determination unit 102 determines that there is a discrepancy between the first coordinate positional relationship and the first actual coordinate positional relationship, the adjustment instruction unit 103 operates the first actuators 251 and 252 to adjust the plasma 21-1 to be positioned at the same position as in the first coordinate positional relationship. Furthermore, when the determination unit 102 determines that there is a discrepancy between the second coordinate positional relationship stored in the memory unit 101 and the second actual coordinate positional relationship, the adjustment instruction unit 103 operates the second actuators 281 and 282 to change the emission angle of the laser beam 21 incident on the second mirror 27-1 from the second mirror 27-1, thereby adjusting the position of the escaping light 21-2 to be positioned at the same position as in the second coordinate positional relationship. In the second embodiment, when the determination unit 102 determines that there is a discrepancy between the second coordinate positional relationship and the second actual coordinate positional relationship, the adjustment instruction unit 103 operates the second actuators 281 and 282 to change the orientation of the reflecting surface 271 of the second mirror 27-1 so that both distances 714 and 715, which are the second actual coordinate positional relationship, become zero.

[0080] In the laser processing apparatus 1-2 according to the second embodiment, the determination unit 102 of the control unit 100 determines whether or not there is a difference between the second coordinate positional relationship and the second actual coordinate positional relationship at the predetermined timing described above, and also determines whether or not there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship, as in the first embodiment. In the laser processing apparatus 1-2 according to the second embodiment, in a normal state, the center 213 of the through-light 21-2 is located at the intersection 713 of the reference lines 711 and 712 in the captured image 700 captured by the through-light imaging unit 70. In addition, in the laser processing apparatus 1-2 according to the second embodiment, when the laser beam 21 is misaligned and deviates from the normal optical axis due to changes over time or the like, the center 213 of the through-light 21-2 is misaligned from the intersection 713 of the reference lines 711 and 712 in the captured image 700 captured by the through-light imaging unit 70.

[0081] The laser processing apparatus 1-2 according to the second embodiment determines whether there is a difference between the second coordinate positional relationship and the second actual coordinate positional relationship, and when determining whether there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship, the control unit 100 controls the moving unit 30 to position the condenser lens 23 of the laser beam irradiating unit 20-2 above the output measuring unit 60 at a position where a focal point 211 is formed between the condenser lens 23 and the light receiving surface 61 of the output measuring unit 60. In the laser processing apparatus 1-2, the control unit 100 controls the laser beam irradiating unit 20-2 to irradiate the output measuring unit 60 with the laser beam 21 for a predetermined time, and causes the through-light imaging unit 70 to image the through-light 21-2.

[0082] In the laser processing apparatus 1-2, the control unit 100 acquires a captured image 700, and the determination unit 102 determines whether or not there is a difference between the second coordinate positional relationship stored in the memory unit 101 and the second actual coordinate positional relationship of the captured image 700. When the determination unit 102 of the control unit 100 determines that there is a difference between the second coordinate positional relationship stored in the memory unit 101 and the second actual coordinate positional relationship of the captured image 700, the adjustment instruction unit 103 operates the second actuators 281 and 282 to change the orientation of the reflecting surface 271 of the second mirror 27-1 so that the through light 21-2 is positioned at the same position as the second coordinate positional relationship, that is, so that the center 213 of the through light 21-2 is positioned at the intersection 713 of the reference lines 711 and 712 of the captured image 700.

[0083] In the laser processing apparatus 1-2 according to the second embodiment, after the adjustment instruction unit 103 of the control unit 100 changes the orientation of the reflecting surface 271 of the second mirror 27-1, or after the judgment unit 102 determines that there is no difference between the second coordinate position relationship stored in the memory unit 101 and the second actual coordinate position relationship of the captured image 700, the control unit 100 controls the laser beam irradiation unit 20-2 to irradiate the laser beam 21 from the laser beam irradiation unit 20-2 to the output measuring unit 60 for a predetermined time, and causes the plasma imaging unit 50 to image the plasma 21-1 generated at the focal point 211.

[0084] In the laser processing apparatus 1-2 according to the second embodiment, the control unit 100 acquires a captured image 500, and the determination unit 102 determines whether or not there is a difference between the first coordinate positional relationship stored in the storage unit 101 and the first actual coordinate positional relationship of the captured image 500. When the determination unit 102 of the control unit 100 determines that there is a difference between the first coordinate positional relationship stored in the storage unit 101 and the first actual coordinate positional relationship of the captured image 500, the adjustment instruction unit 103 operates the first actuators 251 and 252 to change the orientation of the reflecting surface 241 of the first mirror 24 so that the plasma 21-1 is positioned at the same position as the first coordinate positional relationship, that is, so that the center 212 of the plasma 21-1 is positioned at the intersection 513 of the reference lines 511 and 512 of the captured image 500.

[0085] In this way, the laser processing apparatus 1-2 according to the second embodiment positions the laser beam 21 at the correct optical axis position, suppressing positional deviation of the processed groove and enabling the processed groove to be formed at the correct position. In this way, the laser processing apparatus 1-2 performs so-called hairline alignment, which enables the processed groove to be formed at the correct position by positioning the center 212 of the stray light 21-2 at the intersection 713 of the reference lines 711 and 712 in the captured image 700 and positioning the center 212 of the plasma 21-1 at the intersection 513 of the reference lines 511 and 512 in the captured image 500.

[0086] The laser processing apparatus 1-2 according to the second embodiment returns to processing operations, etc., after the adjustment instruction unit 103 of the control unit 100 changes the orientation of the reflecting surface 241 of the first mirror 24, or after the determination unit 102 determines that there is no difference between the first coordinate positional relationship stored in the memory unit 101 and the first actual coordinate positional relationship of the captured image 500. In the present invention, the laser processing apparatus 1-2 may adjust the actuators 25 and 28 by alternately operating them repeatedly until the stray light 21-2 and the plasma 21-1 are positioned in their correct positions. In this case, the order in which the actuators 25 and 28 are operated does not matter. In this case, the laser processing apparatus 1-2 returns to processing operations, etc., once the adjustment of the actuators 25 and 28 is completed.

[0087] In the laser processing apparatus 1-2 according to the second embodiment, the stray light imaging unit 70 captures an image of the stray light 21-2 at a predetermined timing, the determination unit 102 determines whether there is a difference between the second coordinate positional relationship and the second actual coordinate positional relationship, and if it is determined that there is a difference, the adjustment instructing unit 103 adjusts the stray light 21-2 so that it is positioned at the same position as in the second coordinate positional relationship. Furthermore, the laser processing apparatus 1-2 according to the second embodiment further captures an image of the plasma 21-1 using the plasma imaging unit 50, the determination unit 102 determines whether there is a difference between the first coordinate positional relationship and the first actual coordinate positional relationship, and if it is determined that there is a difference, the adjustment instructing unit 103 adjusts the plasma 21-1 so that it is positioned at the same position as in the first coordinate positional relationship. As a result, the laser processing apparatus 1-2 according to the second embodiment, like the first embodiment, can perform so-called hairline alignment without irradiating the laser beam 21 onto a wafer for adjustment to perform processing, thereby enabling high-precision processing while reducing downtime.

[0088] In the present invention, in the second embodiment, imaging unit 40 may also serve as plasma imaging unit 50. That is, in the present invention, the camera that images workpiece 200 and the camera that images plasma 21-1 may be the same. Also, in the present invention, even if only one of stray light 21-2 and plasma 21-1 is deviated from the correct position (i.e., if either one is in the correct position), both first mirror 24 and second mirror 27-1 may be operated to perform alignment.

[0089] The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the gist of the present invention. [Explanation of symbols]

[0090] 1,1-2 Laser processing equipment 10 Holding table 20,20-2 Laser beam irradiation unit 21 Laser Beam 21-1 Plasma 22 Laser oscillator 23 Condenser lens (concentrator) 24 First Mirror 25,251,252 First Actuator 27,27-1,27-2 Second Mirror 28,281,282 Second Actuator 50 Plasma imaging unit 51,511,512 Baseline 70 Light-through imaging unit 71,711,712 Baseline 100 control unit 101 Storage section 102 Judgment section 103 Adjustment instruction section 200 Workpiece 211 Focus point

Claims

1. a holding table for holding the workpiece; a laser beam irradiation unit that irradiates a laser beam onto the workpiece held on the holding table; A laser processing apparatus comprising: a control unit for controlling each component; a plasma imaging unit having a reference line within an imaging area and imaging plasma generated at a focal point of the laser beam; The laser beam irradiation unit comprises: A laser oscillator; a condenser that condenses the laser beam emitted from the laser oscillator and irradiates the laser beam onto the workpiece; a first mirror disposed between the laser oscillator and the condenser, for reflecting the laser beam to change its traveling direction; a first actuator that operates the first mirror to change the exit angle of the laser beam incident on the first mirror; The control unit a storage unit that stores a first coordinate positional relationship, which is a relative coordinate positional relationship between the plasma generated at the focal point and a reference line of the plasma imaging unit at the design stage; a determination unit that determines whether or not there is a difference between the first coordinate positional relationship and a first actual coordinate positional relationship that is a relative coordinate positional relationship between the plasma and the reference line obtained by actual measurement; an adjustment instruction unit that, when the determination unit determines that there is a discrepancy, operates the first actuator to change the emission angle of the laser beam incident on the first mirror, thereby making an adjustment so that the plasma is positioned at the same position as the first coordinate positional relationship; A laser processing device comprising:

2. The laser beam irradiation unit comprises: a second mirror disposed between the laser oscillator and the condenser for reflecting the laser beam to change its direction of travel; a second actuator that operates the second mirror to change the exit angle of the laser beam incident on the second mirror; Equipped with a stray light imaging unit having a reference line within an imaging area and configured to image stray light of the laser beam that is transmitted without being reflected by the second mirror; The storage unit Further storing a second coordinate positional relationship which is a relative coordinate positional relationship between the stray light and the reference line of the stray light imaging unit at the design stage; The determination unit Further determining whether or not there is a difference between the second coordinate positional relationship and a second actual coordinate positional relationship, which is a relative coordinate positional relationship between the stray light and a reference line of the stray light imaging unit obtained by actual measurement; The adjustment instruction unit When the determining unit determines that there is a difference, at least one of the first actuator and the second actuator is operated to adjust the optical path of the laser beam so that the plasma is positioned at the same position as in the first coordinate positional relationship and the escaping light is positioned at the same position as in the second coordinate positional relationship. The laser processing device according to claim 1.

Images