Method for adjusting laser processing device, and laser processing device

Abstract

To provide an adjustment method of a laser processing device that can properly correct aberration of a light collector constituting an optical system of laser irradiation means.SOLUTION: The adjustment method of a laser processing device is configured to include an imaging step of making imaging means image, and an aberration correcting step of comparing a desired positional relation as a reference for adjustment in a spatial light modulator adjustment step with a positional relation between a plurality of machining traces imaged in the imaging step and correcting aberration of a light collector by adjusting a spatial light modulator so that the positional relation between the machining traces matches the desired positional relation.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for adjusting a laser processing apparatus that irradiates a laser beam onto a workpiece held by a holding means, and to a laser processing apparatus. [Background technology]

[0002] Wafers on which a number of devices such as ICs and LSIs are formed on their surface, partitioned by planned division lines, are separated by laser processing equipment into individual device chips for use in electrical equipment such as mobile phones and personal computers.

[0003] The laser processing apparatus at least comprises a holding means for holding the workpiece, a laser irradiation means for irradiating the workpiece held by the holding means with a laser beam, and a feeding means for feeding the holding means and the laser irradiation means relatively for processing, and can divide a wafer into individual device chips with high precision (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-051517 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when laser processing is performed by irradiating a laser beam, there is a problem that the processing accuracy of the workpiece is reduced due to aberration in the optical system including the condenser that constitutes the laser irradiation means, and improvement is required.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its main technical object is to provide an adjustment method for a laser processing apparatus, and a laser processing apparatus, which can appropriately correct the aberration of a collector that constitutes the optical system of a laser irradiation means. [Means for solving the problem]

[0007] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a method for adjusting a laser processing apparatus including a holding means for holding a workpiece, a laser irradiation means for irradiating a laser beam onto the workpiece held by the holding means, and a feed means for relatively feeding the holding means and the laser irradiation means for processing, the laser irradiation means including an oscillator for emitting a laser beam, a condenser for condensing the laser beam oscillated by the oscillator, a spatial light modulator disposed between the oscillator and the condenser, a spectrometer disposed between the condenser and the spatial light modulator, and an imaging means disposed on the side where the beam is split by the condenser, and a processing mark is formed on the workpiece by irradiation with the laser beam. a wafer preparation step of preparing a wafer, a holding step of holding the wafer on the holding means, a spatial light modulator adjustment step of adjusting the spatial light modulator to make the laser beam oscillated by the oscillator in a state in which a plurality of laser beams can be irradiated so as to have a desired positional relationship, a processing mark forming step of operating the oscillator to irradiate the wafer held by the holding means with a laser beam to form a plurality of processing marks, an imaging step of stopping the operation of the oscillator and imaging the processing marks formed on the wafer held by the holding means by the imaging means, and a spatial light modulator adjustment step of comparing the desired positional relationship serving as a reference for adjustment in the spatial light modulator adjustment step with the positional relationship of the plurality of processing marks imaged in the imaging step to image the processing marks. In plan view and an aberration correcting step of correcting the aberration of the condenser by adjusting the spatial light modulator so that the positional relationship becomes the desired positional relationship. In the spatial light modulator adjusting step, it is preferable to adjust the focal point of the laser beam so as to be positioned on the surface of the wafer. In the imaging step, it is preferable to image the positional relationship formed by processing marks formed on the surface of the wafer by the imaging means.

[0008] According to the present invention, there is provided a laser processing apparatus including a holding means for holding a workpiece, a laser irradiation means for irradiating a laser beam onto the workpiece held by the holding means, a feed means for relatively feeding the holding means and the laser irradiation means for processing, and a control means, wherein the laser irradiation means includes an oscillator for emitting a laser beam, a condenser for condensing the laser beam oscillated by the oscillator, a spatial light modulator disposed between the oscillator and the condenser, a spectrometer disposed between the condenser and the spatial light modulator, and an imaging means disposed on the side of the laser beam split by the condenser. the control means includes a spatial light modulator adjustment instruction section for adjusting the spatial light modulator to make the laser beam oscillated by the oscillator in a state in which a plurality of laser beams can be irradiated so as to have a desired positional relationship; a processing mark formation instruction section for operating the oscillator to irradiate the wafer held by the holding means with a laser beam to form a plurality of processing marks; an imaging instruction section for stopping the operation of the oscillator and imaging the processing marks formed on the wafer held by the holding means by the imaging means; and In plan view and an aberration correction instruction unit which compares the positional relationship with the desired positional relationship and adjusts the spatial light modulator to correct the aberration of the condenser so that the positional relationship of the processing marks becomes the desired positional relationship. Effect of the Invention

[0009] The method for adjusting a laser processing apparatus of the present invention is a method for adjusting a laser processing apparatus comprising: a holding means for holding a workpiece; a laser irradiation means for irradiating a laser beam onto the workpiece held by the holding means; and a feed means for relatively feeding the holding means and the laser irradiation means for processing, the laser irradiation means comprising: an oscillator for emitting a laser beam; a condenser for condensing the laser beam oscillated by the oscillator; a spatial light modulator disposed between the oscillator and the condenser; a spectrometer disposed between the condenser and the spatial light modulator; and an imaging means disposed on the side where the beam is split by the condenser; a wafer preparation step of preparing a wafer (C) for use in a wafer holding step of holding the wafer in the holding means; a spatial light modulator adjustment step of adjusting the spatial light modulator to make the laser beam oscillated by the oscillator capable of irradiating a plurality of laser beams so as to have a desired positional relationship; a processing mark forming step of operating the oscillator to irradiate the wafer held in the holding means with a laser beam to form a plurality of processing marks; an imaging step of stopping the operation of the oscillator and imaging the processing marks formed on the wafer held in the holding means by the imaging means; and a spatial light modulator adjustment step of comparing the desired positional relationship serving as a reference for adjustment in the spatial light modulator adjustment step with the positional relationship of the plurality of processing marks imaged in the imaging step to obtain a spatial light modulator image of the processing marks. In plan view and an aberration correction step of correcting the aberration of the collector by adjusting the spatial light modulator so that the positional relationship becomes the desired positional relationship. This solves the problem that the aberration of the optical system including the collector that constitutes the laser irradiation means reduces the processing accuracy of the workpiece.

[0010] The laser processing apparatus of the present invention is a laser processing apparatus including a holding means for holding a workpiece, a laser irradiation means for irradiating a laser beam onto the workpiece held by the holding means, a feed means for relatively feeding the holding means and the laser irradiation means for processing, and a control means, wherein the laser irradiation means includes an oscillator for emitting a laser beam, a condenser for condensing the laser beam oscillated by the oscillator, a spatial light modulator disposed between the oscillator and the condenser, a spectrometer disposed between the condenser and the spatial light modulator, and an imaging means disposed on the side split by the spectroscope. the control means includes a spatial light modulator adjustment instruction section for adjusting the spatial light modulator to make the laser beam oscillated by the oscillator in a state in which a plurality of laser beams can be irradiated so as to have a desired positional relationship; a processing mark formation instruction section for operating the oscillator to irradiate the wafer held by the holding means with a laser beam to form a plurality of processing marks; an imaging instruction section for stopping the operation of the oscillator and imaging the processing marks formed on the wafer held by the holding means by the imaging means; and In plan view and an aberration correction instruction unit which compares the positional relationship with the desired positional relationship and adjusts the spatial light modulator to correct the aberration of the collector so that the positional relationship of the processing marks becomes the desired positional relationship, thereby eliminating the problem that the aberration of the optical system including the collector that constitutes the laser irradiation means reduces the processing accuracy of the workpiece. [Brief description of the drawings]

[0011] [Figure 1] 1 is an overall perspective view of a laser processing apparatus according to an embodiment of the present invention; [Diagram 2] 2 is a block diagram showing an outline of a laser irradiation means attached to the laser processing apparatus shown in FIG. 1. FIG. [Diagram 3] 3 is a schematic diagram showing an outline of a 4f optical system configured in the laser irradiation means shown in FIG. 2. [Figure 4] FIG. 1A is a conceptual diagram showing a desired positional relationship formed by target machining positions, and FIG. 1B is a conceptual diagram showing a positional relationship formed by actual machining marks. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a laser processing apparatus and a method for adjusting a laser processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

[0013] 1 shows an overall perspective view of a laser processing apparatus 2 according to this embodiment. In the adjustment method for a laser processing apparatus carried out by the laser processing apparatus 2 of this embodiment, as shown in the figure, a disk-shaped test wafer 10 is processed as a workpiece. The wafer 10 is a wafer on which processing marks are formed by irradiation with a laser beam LB, which will be described later. For example, the surface 10a of the wafer 10 is coated with tin (Sn), and the wafer 10 is supported by an annular frame F via an adhesive tape T.

[0014] The laser processing apparatus 2 includes at least a chuck table 25 arranged as a holding means for holding the wafer 10, a laser irradiation means 6 for irradiating the wafer 10 held on the chuck table 25 with a laser beam LB, a feeding means 30 for feeding the chuck table 25 and the laser irradiation means 6 relatively for processing, and a control means 100 (see FIG. 2) described later.

[0015] Moreover, the laser processing device 2 of this embodiment is provided with an alignment means 7 for capturing an image of the workpiece and detecting the position to be processed, and a display means 8, in addition to the above-mentioned configuration.

[0016] The chuck table mechanism 20 including the chuck table 25 includes a rectangular X-axis direction movable plate 21 mounted on the base 3 so as to be movable in the X-axis direction, a rectangular Y-axis direction movable plate 22 mounted so as to be movable in the Y-axis direction along the guide rails 21a, 21a on the X-axis direction movable plate 21, a cylindrical support 23 fixed to the upper surface of the Y-axis direction movable plate 22, and a rectangular cover plate 26 fixed to the upper end of the support 23. The chuck table 25 is a circular member extending upward through an elongated hole formed on the cover plate 26, and is configured to be rotatable by a rotation drive means (not shown). The chuck table 25 has a holding surface 25a formed of a porous material having air permeability and defined by the X-axis direction and the Y-axis direction. The holding surface 25a is connected to a suction means (not shown) by a flow path passing through the support 23. The X-axis direction is the direction indicated by the arrow X in FIG. 1, and the Y-axis direction is the direction indicated by the arrow Y, which is perpendicular to the X-axis direction. The plane defined by the X-axis direction and the Y-axis direction is substantially horizontal.

[0017] The feed means 30 includes an X-axis moving means 31 for relatively moving the chuck table 25 and the laser irradiation means 6 in the X-axis direction for machining, and a Y-axis moving means 32 for relatively moving the chuck table 25 and the laser irradiation means 6 in the Y-axis direction. The X-axis moving means 31 includes a ball screw 34 extending in the X-axis direction on the base 3, and a motor 33 connected to one end of the ball screw 34. A nut portion (not shown) of the ball screw 34 is formed on the lower surface of the X-axis direction movable plate 21. The X-axis moving means 31 converts the rotational motion of the motor 33 into linear motion by the ball screw 34 and transmits it to the X-axis direction movable plate 21, and moves the X-axis direction movable plate 21 forward and backward in the X-axis direction along the guide rails 3a, 3a on the base 3. The Y-axis moving means 32 includes a ball screw 36 extending in the Y-axis direction on the X-axis direction movable plate 21, and a motor 35 connected to one end of the ball screw 36. A nut portion (not shown) of the ball screw 36 is formed on the lower surface of the Y-axis direction movable plate 22. The Y-axis moving means 32 converts the rotational motion of the motor 35 into linear motion by the ball screw 36 and transmits it to the Y-axis direction movable plate 22, and moves the Y-axis direction movable plate 22 forward and backward in the Y-axis direction along the guide rails 21a, 21a on the X-axis direction movable plate 21.

[0018] At the back side of the chuck table mechanism 20, a frame 37 is erected, which includes a vertical wall portion 37a extending in the vertical direction (Z-axis direction) from the upper surface of the base 3, and a horizontal wall portion 37b extending horizontally. The horizontal wall portion 37b houses the optical system of the laser irradiation means 6 and the alignment means 7. A condenser 61 constituting the laser irradiation means 6 is disposed on the lower surface of the tip of the horizontal wall portion 37b, and an objective lens 71 of the alignment means 7 is disposed at a position spaced apart from the condenser 61 in the X-axis direction. The above-mentioned laser irradiation means 6 is a means for irradiating the wafer 10 with a laser beam LB having a wavelength that is absorbent or transmissive, and in this embodiment, the laser processing conditions are set to perform ablation processing on a tin (Sn) film coated on the surface 10a of the wafer 10. The objective lens 71 shown in the figure is an objective lens housed in a cylindrical case. The above-mentioned alignment means 7, display means 8, feed means 30, etc. are electrically connected to a control means 100 (see Figure 2) that controls the laser irradiation means 6 of this embodiment, and are controlled based on instruction signals sent from the control means 100, thereby performing laser processing of the wafer 10 and a method for adjusting the laser processing apparatus 2.

[0019] The optical system of the laser irradiation means 6 of this embodiment will be described with reference to Fig. 2. The laser irradiation means 6 includes at least an oscillator 62 that oscillates a laser beam LB, a condenser 61 including a condenser lens 61a that condenses the laser beam LB oscillated by the oscillator 62 onto the wafer 10, a spatial light modulator (SLM) 65 disposed between the oscillator 62 and the condenser 61, a spectrometer 67 disposed between the spatial light modulator 65 and the condenser 61, and an imaging means 80 disposed on the side where the light is split by the spectrometer 67. The spatial light modulator 65 is, for example, configured as a transmissive type (LC), but may also be configured as a reflective type (LCOS).

[0020] The laser irradiation means 6 further includes, as components that are arranged as necessary, an attenuator 63 that adjusts the output of the laser beam LB oscillated from the oscillator 62, a polarizing plate 64 that aligns the polarization state of the laser beam LB oscillated from the oscillator 62, a lens 66 including two convex lenses, a reflection mirror 68 that reflects the laser beam LB from the spectrometer 67 and directs it toward the collector 61, and a reflection mirror 69 arranged on the side of the optical path where the laser beam is split by the spectrometer 67.

[0021] FIG. 3 shows a conceptual diagram of a 4f optical system including the lens 66 configured in the laser irradiation means 6 of this embodiment. The lens 66 in the 4f optical system of this embodiment includes a first convex lens 66a and a second convex lens 66b, and is configured so that a back focal plane located at a distance f1 downstream (the condenser lens 61a side) from the first convex lens 66a and a front focal plane located at a distance f2 upstream (the spatial light modulator 65 side) from the second convex lens 66b coincide at the position of point P, and an image formed by the spatial light modulator 65 located at a distance f1 upstream of the first convex lens 66a is accurately transferred (imaged) by the condenser lens 61a located at a distance f2 downstream of the second convex lens 66b. Note that the diagram shown in FIG. 3 is merely a conceptual diagram, and the lengths of the distances f1 and f2 shown in the diagram are not in accordance with the actual dimensional ratio.

[0022] The spectroscope 67 is a so-called beam splitter, which transmits a part of the laser beam LB irradiated from the lens 66. The optical path of the laser beam LB transmitted through the spectroscope 67 is changed by a reflecting mirror 68 and guided to the condenser 61 side. In addition, a part of the light reflected from the condenser 61 by the wafer 10, which is the workpiece, is dispersed by the spectroscope 67 and is guided to the imaging means 80 disposed on the side where the light is dispersed, and imaged.

[0023] Returning to FIG. 2, the oscillator 62 , the spatial light modulator 65 , and the imaging means 80 are connected to a control means 100 . The control means 100 is capable of adjusting the spatial light modulator 65, and is equipped with a spatial light modulator adjustment instruction unit 110 that issues an instruction signal to the spatial light modulator 65 so that, when the laser beam LB oscillated by the oscillator 62 is brought into a state in which a plurality of laser beams LB can be irradiated, each of the laser beams LB has a desired positional relationship, and is also configured to include a processing mark formation instruction unit 120 that instructs the oscillator 62 to operate to irradiate the laser beam LB on the wafer 10 held on the chuck table 25 to form processing marks, an imaging instruction unit 130 that stops the operation of the oscillator 62 and instructs the imaging means 80 to image the processing marks formed on the wafer 10 held on the chuck table 25, and an aberration correction instruction unit 140 that compares the desired positional relationship instructed by the spatial light modulator adjustment instruction unit 110 with the positional relationship of the actual processing marks imaged by the imaging means 80, and adjusts the spatial light modulator 65 so that the desired position is achieved based on the deviation, thereby correcting the aberration of the condenser 61. The control means 100 is connected to the display means 8, and can display on the display means 8 the above-mentioned alignment means 7, images captured by the imaging means 80, laser processing conditions, and the like.

[0024] The control means 100 is configured by a computer, and includes a central processing unit (CPU) that performs calculation processing according to a control program, a read-only memory (ROM) that stores the control program, etc., a readable / writable random access memory (RAM) for temporarily storing the detected values, calculation results, etc., an input interface, and an output interface (details are not shown in the drawings). The spatial light modulator adjustment instruction unit 110, the processing mark formation instruction unit 120, the imaging instruction unit 130, and the aberration correction instruction unit 140 are configured by a control program, and are stored in the ROM of the control means 100.

[0025] The laser processing apparatus 2 of this embodiment has a configuration generally as described above, and the functions and actions of the laser processing apparatus 2 and an embodiment of a laser processing method performed by the laser processing apparatus 2 will be described below.

[0026] First, a wafer preparation step is carried out to prepare a wafer 10 as a workpiece on which processing marks are formed by irradiation with a laser beam LB. The wafer 10 used in this embodiment has a surface 10a coated with tin (Sn) as described with reference to Fig. 1. The wafer used in the method for adjusting a laser processing apparatus of the present invention is not limited to the wafer 10 having a surface 10a coated with tin as described above, and may be any wafer on which processing marks are formed by irradiation with a laser beam LB.

[0027] Once the wafer 10 has been prepared, the wafer 10 is then placed and held on the holding surface 25a of the chuck table 25 (holding step). When holding the wafer 10 on the chuck table 25, the suction means is operated to suction and hold the wafer 10 on the holding surface 25a.

[0028] Next, the spatial light modulator adjustment instruction unit 110 of the control means 100 is operated to send an instruction signal to the spatial light modulator 65 based on the desired positional relationship 12a (see Figure 4(a)) previously stored in the control means 100, thereby adjusting the laser beam LB oscillated by the oscillator 62 so that multiple laser beams LB can be irradiated so as to have the desired positional relationship 12a (spatial light modulator adjustment process).

[0029] Next, the processing mark formation instruction unit 120 of the control means 100 is operated to operate the oscillator 62 and perform the processing mark formation step of irradiating the wafer 10 held on the chuck table 25 with a laser beam LB to form processing marks. At this time, the chuck table 25 holding the wafer 10 is positioned directly below the condenser 61 of the laser irradiation means 6 by operating the above-mentioned feed means 30, and the position of the condenser 61 is adjusted in the vertical direction (Z-axis direction) by operating a moving means (not shown), and the focal point of the laser beam LB focused by the condenser 61 is adjusted to be on the surface 10a of the wafer 10.

[0030] Here, the desired positional relationship 12a is, for example, a positional relationship formed by 25 (5×5) target processing positions 14a arranged at equal intervals of 10 μm in a space of 40 μm square in a plan view on the surface 10a of the wafer 10, as shown in FIG. 4(a). The control means 100 stores positional information of each of the 25 target processing positions 14a in advance, and the spatial light modulator 65 is adjusted based on an instruction signal sent from the spatial light modulator adjustment instruction unit 110, so that the laser beam LB is irradiated to form processing marks at the coordinate positions of each of the 25 target processing positions 14a. As described above, the spatial light modulator adjustment step and the processing mark formation step are performed based on the instruction signals from the spatial light modulator adjustment instruction unit 110 and the processing mark formation instruction unit 120, so that 25 processing marks 14b are formed on the surface 10a of the wafer 10 by the laser beam LB, as shown in FIG. 4(b).

[0031] The laser processing conditions instructed by the processing mark formation instructing unit 120 are set, for example, as follows. Laser beam wavelength: 532nm~1550nm Repetition frequency: 10~200kHz Average power output: 0.1~10W Feed speed: 10~2000mm / sec

[0032] Here, in the spatial light modulator adjustment instruction unit 110, an instruction signal is sent to the spatial light modulator 65 so that the processing mark 14b formed on the surface 10a of the wafer 10 has the desired positional relationship 12a shown in FIG. 4(a), and if the laser beam LB is accurately irradiated according to this instruction, the processing mark that coincides with the desired positional relationship 12a should be formed on the surface 10a of the wafer 10. However, in reality, due to aberration of the optical system, the desired positional relationship 12a is not achieved, and as shown in FIG. 4(b), the processing mark 14b is formed on the surface 10a of the wafer 10, which is shifted from the target processing position 14a, and the processing mark 14b forms a positional relationship 12b that is disturbed with respect to the desired positional relationship 12a. In such a state, when laser processing is performed via the spatial light modulator 65, the aberration is not properly corrected, and the aberration causes a problem of reducing the processing accuracy.

[0033] Therefore, in this embodiment, first, after performing the above-mentioned processing mark forming step, the operation of the oscillator 62 is stopped, and the positional relationship 12b formed by the actual processing mark 14b formed on the front surface 10a of the wafer 10 held on the chuck table 25 is imaged by the above-mentioned imaging means 80 (imaging step). Image information indicating the positional relationship 12b imaged by the imaging step is recorded in the memory (RAM) of the control means 100.

[0034] After the imaging step is performed, the desired positional relationship 12a, which is the reference for the instruction in the spatial light modulator adjustment step, is compared with the actual positional relationship 12b formed by the processing marks 14b imaged in the imaging step and recorded in the control means 100, to detect a positional deviation between the desired positional relationship 12a and the positional relationship 12b, and the spatial light modulator 65 is adjusted so that the positional relationship 12b is corrected to match the desired positional relationship 12a, and the adjustment value used for the adjustment is recorded in the control means 100. Then, the adjustment value is reflected in the control of the spatial light modulator 65 by the control means 100, thereby correcting the aberration of the optical system of the laser irradiation means 6 including the condenser 61 when performing laser processing by the laser irradiation means 6 (aberration correction step). This allows the aberration of the optical system of the laser irradiation means 6 to be appropriately corrected, and the problem of the processing accuracy being reduced due to the aberration is eliminated.

[0035] In the above embodiment, the desired positional relationship 12a formed by the 25 target processing positions 14a is compared with the positional relationship 12b formed by the 25 actually formed processing marks 14b, and the spatial light modulator 65 is adjusted so that the actual positional relationship 12b becomes the desired positional relationship 12a, but the present invention is not limited to this. For example, the positions of the target processing positions 14a forming the desired positional relationship 12a may be individually compared with the positions of the actual individual processing marks 14b, and the spatial light modulator 65 may be adjusted so that the target processing positions 14a corresponding to each processing mark 14b and the processing marks 14b coincide with each other.

[0036] In the above embodiment, in the machining mark forming step, the focal point of the laser beam LB is positioned on the surface 10a of the wafer 10 held on the chuck table 25 and the laser beam LB is irradiated to form the machining mark 14b on the surface 10a, and the imaging step and the aberration correction step are performed, but the present invention is not limited to this, and for example, the focal point may be positioned inside the wafer 10 and the laser beam LB having a wavelength that is transparent to the wafer 10 may be irradiated to form a plurality of machining marks inside the wafer 10. In that case, the imaging means 80 may be provided with an infrared irradiation means and an infrared imaging element to be configured so that the machining marks formed inside the wafer 10 can be detected. [Explanation of symbols]

[0037] 2: Laser processing equipment 3: Base 6: Laser irradiation means 61: Concentrator 61a: Condenser lens 62: Oscillator 63: Attenuator 64: Polarizing plate 65: Spatial light modulator 66: Lens 67: Spectroscope (beam splitter) 68, 69: Reflective mirror 7: Alignment means 71: Objective lens 8:Display means 10: Wafer 10a: surface 12a: Desired positional relationship 12b: Actual positional relationship 14a: Target machining position 14b: Machining marks 20: Chuck table mechanism 21:X-axis movable plate 22: Y-axis direction movable plate 25: Chuck table 30:Transportation means 31:X-axis movement means 32: Y-axis movement means 37:Frame body 80: Imaging means 100: Control means 110: spatial light modulator adjustment instruction unit 120: Machining mark formation instruction section 130: Imaging instruction unit 140: Aberration correction indicator

Claims

1. A method for adjusting a laser processing apparatus including a holding means for holding a workpiece, a laser irradiation means for irradiating a laser beam onto the workpiece held by the holding means, and a feed means for relatively feeding the holding means and the laser irradiation means for processing, comprising the steps of: The laser irradiation means is the optical fiber includes an oscillator for emitting a laser beam, a condenser for condensing the laser beam emitted by the oscillator, a spatial light modulator disposed between the oscillator and the condenser, a spectrometer disposed between the condenser and the spatial light modulator, and an imaging means disposed on a side where the laser beam is dispersed by the condenser, a wafer preparation step of preparing a wafer as a workpiece on which a processing mark is formed by irradiation with a laser beam; a holding step of holding the wafer on the holding means; a spatial light modulator adjusting step of adjusting the spatial light modulator so that the laser beam oscillated by the oscillator can be irradiated with a plurality of laser beams so as to have a desired positional relationship; a processing mark forming step of irradiating the wafer held by the holding means with a laser beam by operating the oscillator to form a plurality of processing marks; an imaging step of stopping the operation of the oscillator and imaging a processed mark formed on the wafer held by the holding means with the imaging means; an aberration correction step of comparing the desired positional relationship serving as a reference for adjustment in the spatial light modulator adjustment step with the positional relationship between the plurality of processing marks captured in the imaging step, and adjusting the spatial light modulator to correct the aberration of the condenser so that the positional relationship of the processing marks in a plan view becomes the desired positional relationship; A method for adjusting a laser processing apparatus comprising the steps of:

2. A laser processing apparatus comprising: a holding means for holding a workpiece; a laser irradiation means for irradiating a laser beam onto the workpiece held by the holding means; a feed means for relatively feeding the holding means and the laser irradiation means for processing; and a control means, The laser irradiation means is the optical fiber includes an oscillator for emitting a laser beam, a collector for collecting the laser beam emitted by the oscillator, a spatial light modulator disposed between the oscillator and the collector, a spectrometer disposed between the collector and the spatial light modulator, and an imaging means disposed on the side of the laser beam split by the spectrometer, The control means a spatial light modulator adjustment instruction unit that adjusts the spatial light modulator to make the laser beam oscillated by the oscillator into a state in which a plurality of laser beams can be irradiated so as to have a desired positional relationship; a processing mark formation instruction unit that operates the oscillator to irradiate the wafer held by the holding means with a laser beam to form a plurality of processing marks; an imaging instruction unit that stops the operation of the oscillator and images the processing marks formed on the wafer held by the holding means by the imaging means; and an aberration correction instruction unit that compares the desired positional relationship instructed by the spatial light modulator adjustment instruction unit with the positional relationship of the actual processing marks imaged by the imaging means, and adjusts the spatial light modulator to correct the aberration of the condenser so that the positional relationship in a plan view of the processing marks becomes the desired positional relationship. A laser processing device comprising:

3. A method for adjusting a laser processing apparatus as described in claim 1, wherein, in the spatial light modulator adjustment process, the focal point of the laser beam is adjusted to be positioned on the surface of the wafer.

4. A method for adjusting a laser processing apparatus as described in claim 1, wherein, in the imaging process, the positional relationship formed by processing marks formed on the surface of the wafer is imaged by the imaging means.

Images