Laser processing device

Abstract

The present application provides a laser processing device capable of shortening the time required for adjusting the output of laser. In the laser processing device (1), the control section (50) performs: a first adjustment process of adjusting the output of laser (L) emitted from the condenser lens (33) by causing the spatial light modulator (7) to display a modulation pattern in a manner that the amount of laser (L) emitted from the spatial light modulator (7) and incident to the condenser lens (33) varies; and a second adjustment process of adjusting the output of laser (L) by driving the λ / 2 wavelength plate (61) in a manner that the output of laser (L) and the amount of adjustment in the first adjustment process together become a target value at the time of laser processing.

Description

TECHNICAL FIELD

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

[0002] A laser cutting apparatus is described in Patent Literature 1. The laser cutting apparatus includes a stage that moves a wafer, a laser head that irradiates a laser to the wafer, and a control section that controls each section. The laser head has a laser light source that emits a processing laser for forming a modified region inside the wafer, and a dichroic mirror and a condenser lens that are sequentially arranged on an optical path of the processing laser.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent No. 5743123 SUMMARY

[0006] However, in a laser processing apparatus, there is a case where an attenuator is used to attenuate the output of a laser emitted from a light source to a suitable output before irradiating the laser to an object. As one example, it is possible to consider that the attenuator is configured using a λ / 2 wavelength plate for changing the polarization direction of the laser, a rotation stage that rotationally drives the λ / 2 wavelength plate, and a polarizing plate that the laser emitted from the λ / 2 wavelength plate is incident to. In such an attenuator, the laser of linear polarization that is incident to the λ / 2 wavelength plate is incident to the polarizing plate after the polarization direction is changed by the λ / 2 wavelength plate.

[0007] The laser that is incident to the polarizing plate is separated into a polarization component (for example, a P-polarization component) that transmits through the polarizing plate and a polarization component (for example, an S-polarization component) that is reflected by the polarizing plate. Thus, in such an attenuator, it is possible to adjust the ratio of the transmission component and the reflection component of the polarizing plate by adjusting the amount of driving of the rotational driving of the λ / 2 wavelength plate, and to arbitrarily attenuate the output of the laser. However, in such an attenuator, when the desired amount of attenuation becomes large, the amount of driving of the λ / 2 wavelength plate for achieving the amount of attenuation also becomes large. That is, the time required until the amount of driving of the λ / 2 wavelength plate reaches the necessary amount of driving becomes long. As a result, there is a concern that the time taken to adjust the output of the laser becomes long.

[0008] Therefore, an object of the present application is to provide a laser processing apparatus that can shorten the time required to adjust the output of a laser.

[0009] The laser processing apparatus of the present application includes: a support section for supporting an object; a light source for emitting laser light; a laser light irradiation section for irradiating the laser light emitted from the light source toward the object supported by the support section; and a control section for performing laser processing of the object by controlling at least the laser light irradiation section, the laser light irradiation section having: an attenuator for adjusting the output of the laser light emitted from the light source by an adjustment amount corresponding to the drive amount of a wavelength plate and emitting the laser light; a spatial light modulator for modulating and emitting the laser light emitted from the attenuator according to a modulation pattern; and a condenser lens for condensing the laser light emitted from the spatial light modulator toward the object supported by the support section, the control section performing: a first adjustment process for adjusting the processing output, which is the output of the laser light emitted from the condenser lens, by causing the modulation pattern including the adjustment pattern for modulating the laser light to be displayed on the spatial light modulator in such a manner that the amount of incidence of the laser light emitted from the spatial light modulator and incident on the condenser lens varies; a second adjustment process for adjusting the output of the laser light by driving the wavelength plate in such a manner that the processing output and the adjustment amount in the first adjustment process together become a target value at the time of laser processing; and a laser processing process for performing laser processing using the laser light whose output has been adjusted after the first adjustment process and the second adjustment process.

[0010] In the laser processing apparatus, the laser light emitted from the light source is incident on the condenser lens via the attenuator and is condensed by the condenser lens toward the object. Thus, the output of the laser light irradiated toward the object can be adjusted by adjusting the drive amount of the wavelength plate of the attenuator. Also, in the laser processing apparatus, the laser light is incident on the condenser lens via the spatial light modulator. Thus, the output of the laser light can be further adjusted by controlling the modulation pattern of the spatial light modulator.

[0011] More specifically, in the laser processing apparatus, the control section performs the first adjustment process in which the processing output, which is the output of the laser light emitted from the condenser lens, is adjusted by causing the modulation pattern including the adjustment pattern for modulating the laser light to be displayed on the spatial light modulator in such a manner that the amount of incidence of the laser light incident on the condenser lens varies, and the second adjustment process in which the output of the laser light is adjusted by driving the wavelength plate in such a manner that the processing output and the adjustment amount in the first adjustment process together become a target value at the time of laser processing.

[0012] Thus, in the laser processing apparatus, the adjustment of the output of the laser light is performed by both the attenuator and the spatial light modulator. Thereby, compared with the case where only the attenuator is used, the adjustment amount of the attenuator is reduced, the amount of the drive of the wavelength plate is reduced, and the amount of the load of the spatial light modulator in the adjustment amount targeted is reduced. Thus, the time until the amount of the drive of the wavelength plate reaches the necessary amount can be shortened, and as a result, the time taken for adjusting the output of the laser light can be shortened.

[0013] The laser processing apparatus according to the present application can include a moving section that moves at least one of the support section and the laser irradiation section in a manner that causes the condensing point of the laser light with respect to the object to move relatively, and a control section that performs a first processing and a second processing, and performs a first adjustment processing and a second adjustment processing between the first processing and the second processing, the first processing being a processing that relatively moves the condensing point in a first direction by controlling the moving section, and performs laser processing of the object by scanning the laser light with respect to the object, the second processing being a processing that, after the first processing, relatively moves the condensing point in a second direction opposite to the first direction by controlling the moving section as a laser processing, and performs laser processing of the object by scanning the laser light with respect to the object.

[0014] In this way, in the case of reciprocating processing that scans the laser light in one direction (outbound) and scans the laser light in the opposite direction (return), that is, in the case of adjusting the output of the laser light between the outbound and the return, if the time of the adjustment becomes longer, the waiting time between the outbound and the return becomes longer, and the time of the entire laser processing becomes longer. Thus, in this case, if the time of adjusting the output of the laser light is shortened as described above, the waiting time between the outbound and the return can be reduced, and the time of the entire laser processing can be shortened. That is, in the case of performing reciprocating processing as described above, it is effective to shorten the time involved in adjusting the output of the laser light, in particular.

[0015] In the laser processing apparatus according to the present application, the control section can perform a calibration processing before the first adjustment processing and the second adjustment processing, the calibration processing including a calculation processing that calculates an output difference between a target value in the first processing and a target value in the second processing, a selection processing that selects an adjustment pattern that becomes an adjustment amount corresponding to the output difference calculated in the calculation processing from among a plurality of adjustment patterns that differ in adjustment amount, and a retrieval processing that, after the selection processing, monitors the processing output and drives the wavelength plate in a state in which the adjustment pattern selected in the selection processing is displayed on the spatial light modulator, thereby retrieving a driving amount of the wavelength plate in which the processing output becomes the target value in the second processing. By performing the calibration as described above before the first adjustment processing and the second adjustment processing, the adjustment of the output of the laser light can be performed more correctly and quickly in the first adjustment processing and the second adjustment processing.

[0016] In the laser processing apparatus according to the present application, the control section can hold a table that associates each of a plurality of adjustment patterns that differ in adjustment amount with a control value for displaying each adjustment pattern on the spatial light modulator, and in the selection processing, the adjustment pattern that becomes an adjustment amount corresponding to the output difference calculated in the calculation processing is selected with reference to the table. In this case, the calibration processing can be performed quickly.

[0017] In the laser processing apparatus of the present application, the control section can also cause the condensing point to relatively move in the first direction by the first processing, and start the first adjustment processing and the second adjustment processing at the time point at which the condensing point exits from the object. In this case, the waiting time between the outward journey and the return journey in the reciprocating processing can be further reduced by repeating the time involved in the first adjustment processing and the second adjustment processing and the time between the exit of the condensing point from the object and the stop of the relative movement of the condensing point.

[0018] The laser processing apparatus of the present application can also include a damper disposed between the spatial light modulator and the condensing lens for shielding at least a part of the laser light emitted from the spatial light modulator, and the control section can modulate the laser light in such a manner that a part of the plurality of diffracted lights is shielded by the damper and does not enter the condensing lens by causing the modulation pattern including the diffraction grating pattern for causing the laser light to branch into the plurality of diffracted lights as the adjustment pattern to be displayed on the spatial light modulator in the first adjustment processing. In this case, the output of the laser light can be adjusted easily and reliably using the spatial light modulator.

[0019] In the laser processing apparatus of the present application, the modulation pattern can include a mark displayed outside the region of the spatial light modulator corresponding to the pupil plane of the condensing lens, and the control section can execute the judgment processing for judging the operation state of the spatial light modulator based on the comparison between the image of the laser light emitted from the spatial light modulator and the mark. In this case, the judgment of whether the spatial light modulator is operating normally can be performed.

[0020] According to the present application, a laser processing apparatus capable of reducing the time required for adjusting the output of the laser light can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic view of a laser processing apparatus according to an embodiment.

[0022] Figure 2 is Figure 1 is a schematic view of an attenuator shown in

[0023] Figure 3 is a schematic view of a spatial light modulator shown in Figure 1

[0024] Figure 4 is Figure 1 is a schematic view of a 4f lens unit and a damper shown in

[0025] Figure 5 is a schematic view for explaining the function of the damper shown in Figure 1 , 4

[0026] Figure 6 ​​is a schematic view showing one example of a modulation pattern.

[0027] Figure 7 is a schematic view showing one example of a modulation pattern.

[0028] Figure 8 is a flowchart showing one example of a laser processing method.

[0029] Figure 9 is a schematic view showing an object of laser processing.

[0030] Figure 10 is a schematic view for explaining a procedure of performing laser processing.

[0031] Figure 11 is a schematic view for explaining a procedure of performing laser processing.

[0032] Figure 12 is a flowchart showing a laser processing method of a modification example.

[0033] Figure 13 is a diagram for explaining a judgment process of a modification example.

[0034] Figure 14 is a diagram for explaining a series of actions of a modification example.

[0035] Explanation of symbols

[0036] 1... laser processing apparatus, 6... attenuator, 7... spatial light modulator, 10... light source, 11... object, 20... stage (support portion), 30... laser irradiation portion, 33... condenser lens, 40... moving portion, 50... control portion. DETAILED DESCRIPTION

[0037] Hereinafter, an embodiment will be described in detail with reference to the drawings. In each drawing, the same or equivalent portions will be denoted by the same symbol and repeated explanation will be omitted. In each drawing, a rectangular coordinate system defined by an X axis, a Y axis, and a Z axis will be shown at times.

[0038] Figure 1 is a schematic view showing the structure of a laser processing apparatus of an embodiment. As shown in Figure 1 , the laser processing apparatus 1 includes a light source 10, a stage (support portion) 20, a laser irradiation portion 30, a moving portion 40, and a control portion 50. Here, the laser processing apparatus 1 is an apparatus for forming a modified region 12 in an object 11 by irradiating laser light L to the object 11. In each drawing, a line A representing an imaginary line of processing intended in the object 11 will be shown at times.

[0039] The light source 10 emits laser light L, for example, by a pulse oscillation method. The laser light L emitted from the light source 10 is introduced into the laser light irradiation section 30. In addition, the light source 10 can also be included in the laser light irradiation section 30.

[0040] The stage 20 supports the object 11, for example, by holding a film attached to the object 11. The stage 20 is rotatable with an axis parallel to the Z direction as a rotation axis. The stage 20 can also be movable in the X direction and the Y direction, respectively. In addition, the X direction and the Y direction are a first horizontal direction and a second horizontal direction that intersect (orthogonal to) each other, and the Z direction is a vertical direction. The object 11 has a first surface 11a and a second surface 11b on the opposite side of the first surface 11a. The object 11 is, for example, a wafer including a semiconductor (as one example, a silicon wafer).

[0041] The laser light irradiation section 30 introduces the laser light L emitted from the light source 10, condenses the laser light L, and irradiates the object 11 with the laser light L. Here, the laser light L has a transmissive property with respect to the object 11. When the laser light L is condensed into the inside of the object 11 supported by the stage 20, the laser light L is particularly absorbed in a portion corresponding to a condensing point C of the laser light L, and a modified region 12 is formed in the inside of the object 11. In addition, the condensing point C is a point at which the laser light L is condensed. However, the condensing point C can be a region of a prescribed range from a position of the highest light beam intensity or a position of the center of gravity of the light beam intensity of the laser light L, for example, in a case where the laser light L is modulated in accordance with a modulation pattern indicated in the spatial light modulator 7 (for example, in a case where various aberrations are imparted), or the like, that is, in a case where the laser light L is not condensed at a point.

[0042] The modified region 12 is a region whose density, refractive index, mechanical strength, other physical characteristics, or the like are different from those of a surrounding unmodified region. As the modified region 12, for example, there are a fusion-processed region, a crack region, an insulation breakdown region, a refractive index variation region, and the like. The modified region 12 can be formed in such a manner that a crack extends from the modified region 12 to both the incident side and the opposite side of the laser light L. Such a modified region 12 and a crack are used, for example, for cutting of the object 11.

[0043] As one example, when the stage 20 is moved in the X direction (along the line A) so that the condensing point C is relatively moved in the X direction with respect to the object 11, a plurality of modified light points 12s are formed in a manner of being arranged in one column in the X direction. One modified light point 12s is formed by irradiation with one pulse of the laser light L. One column of modified regions 12 is a collection of a plurality of modified light points 12s arranged in one column. Depending on the relative moving speed of the condensing point C with respect to the object 11 and the repetition frequency of the laser light L, adjacent modified light points 12s exist in a state of being connected to each other or in a state of being separated from each other.

[0044] The moving section 40 includes a first unit 41 for moving the stage 20 in one direction (for example, the X direction) in a plane intersecting (orthogonal to) the Z direction and moving the stage 20 in another direction (for example, the Y direction) in the plane intersecting (orthogonal to) the Z direction. The first unit 41 can also have a function of rotating the stage 20 about an axis parallel to the Z direction as a rotation axis. Further, the moving section 40 includes a second unit 42 that supports the laser irradiation section 30 and moves the laser irradiation section 30 in the X direction, the Y direction, and the Z direction.

[0045] Thus, the condensing point C of the laser L is relatively moved with respect to the object 11 by moving the stage 20 and / or the laser irradiation section 30 in a state where the condensing point C is formed. That is, the moving section 40 can move at least one of the stage 20 and the laser irradiation section 30 in such a manner that the condensing point C of the laser L is relatively moved with respect to the object 11 by driving the first unit 41 and / or the second unit 42.

[0046] The control section 50 controls the operations of the light source 10, the stage 20, the laser irradiation section 30, and the moving section 40. The control section 50 has a processing section, a storage section, and an input receiving section (not shown). The processing section is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the processing section, the processor executes software (programs) read into the memory or the like, controls reading and writing of data in the memory and the storage, and communication performed by the communication device. The storage section is, for example, a hard disk or the like, and stores various data. The input receiving section is an interface section that displays various information and receives input of various information from a user. The input receiving section constitutes a GUI (Graphical User Interface).

[0047] Next, details of the laser irradiation section 30 will be described. The laser irradiation section 30 has an attenuator 6, a spatial light modulator 7, a condensing lens 33, a mirror 34, a 4f lens unit 35, a damper 36, and a camera 37. Here, the attenuator 6 is disposed on an optical path of the laser L between the light source 10 and the spatial light modulator 7. The spatial light modulator 7 is disposed on the optical path of the laser L between the attenuator 6 and the condensing lens 33. In addition, the 4f lens unit 35 and the damper 36 are disposed on the optical path of the laser L between the spatial light modulator 7 and the condensing lens 33.

[0048] Figure 2 is Figure 1 a schematic view of the attenuator shown in FIG. Figure 1 , 2As shown, the attenuator 6 receives laser light L emitted from the light source 10. The attenuator 6 includes a λ / 2 wavelength plate (wavelength plate) 61 for changing the polarization direction of the laser light, a rotating platform 62 for driving the rotation of the λ / 2 wavelength plate 61, and a polarizing plate 63 to receive the laser light L emitted from the λ / 2 wavelength plate 61. In the attenuator 6, the linearly polarized laser light L incident on the λ / 2 wavelength plate 61 has its polarization direction changed by the λ / 2 wavelength plate 61 and is emitted, then incident on the polarizing plate 63.

[0049] The laser L incident on the polarizing plate 63 is separated into a polarized component (laser L) that passes through the polarizing plate 63 (e.g., the P-polarized component) and a polarized component La (e.g., the S-polarized component) that is reflected by the polarizing plate 63. Therefore, in the attenuator 6, the ratio of the transmitted component to the reflected component in the polarizing plate 63 can be adjusted arbitrarily by adjusting the driving amount of the rotation driven by the λ / 2 wavelength plate 61 of the rotating platform 62. That is, the attenuator 6 includes a λ / 2 wavelength plate 61 for adjusting the output of the laser L and emitting it according to an adjustment amount corresponding to the driving amount of the λ / 2 wavelength plate 61.

[0050] Figure 3 It means Figure 1 The diagram shows the structure of a spatial light modulator. Figure 1 , 3 As shown, the spatial light modulator 7 is used to modulate and emit the laser L emitted from the attenuator 6 according to the modulation pattern. The spatial light modulator 7 is, for example, a spatial light modulator (SLM) of reflective liquid crystal (LCOS: Liquid Crystal on Silicon). The spatial light modulator 7 is constructed by sequentially stacking a driving circuit layer 72, a pixel electrode layer 73, a reflective film 74, an alignment film 75, a liquid crystal layer 76, an alignment film 77, a transparent conductive film 78, and a transparent substrate 79 on a semiconductor substrate 71.

[0051] The semiconductor substrate 71 is, for example, a silicon substrate. The driving circuit layer 72 forms an active matrix circuit on the semiconductor substrate 71. The pixel electrode layer 73 includes a plurality of pixel electrodes 73a arranged in a matrix along the surface of the semiconductor substrate 71. Each pixel electrode 73a is formed, for example, of a metal material such as aluminum. A voltage is applied to each pixel electrode 73a by the driving circuit layer 72.

[0052] The reflective film 74 is, for example, a dielectric multilayer film. An alignment film 75 is provided on the surface of the liquid crystal layer 76 on the side of the reflective film 74, and an alignment film 77 is provided on the surface of the liquid crystal layer 76 on the side opposite to the reflective film 74. Each of the alignment films 75, 77 is formed of, for example, a high molecular material such as polyimide, and the contact surface of each of the alignment films 75, 77 with the liquid crystal layer 76 is subjected to, for example, a rubbing treatment. The alignment films 75, 77 align the liquid crystal molecules 76a included in the liquid crystal layer 76 in a certain direction.

[0053] A transparent conductive film 78 is provided on the surface of a transparent substrate 79 on the side of the alignment film 77, and opposes the pixel electrode layer 73 via the liquid crystal layer 76 or the like. The transparent substrate 79 is, for example, a glass substrate. The transparent conductive film 78 is formed of, for example, a material that is optically transmissive and electrically conductive such as ITO. The transparent substrate 79 and the transparent conductive film 78 transmit the laser light L.

[0054] In the spatial light modulator 7 configured in the above-described manner, when a signal representing a modulation pattern is input from the control section 50 to the drive circuit layer 72, a voltage corresponding to the signal is applied to each of the pixel electrodes 73a, and an electric field is formed between each of the pixel electrodes 73a and the transparent conductive film 78. When the electric field is formed, in the liquid crystal layer 76, the alignment direction of the liquid crystal molecules 76a changes in each region corresponding to each of the pixel electrodes 73a, and the refractive index changes in each region corresponding to each of the pixel electrodes 73a. This state is a state in which the modulation pattern is displayed in the liquid crystal layer 76. The modulation pattern is used to modulate the laser light L.

[0055] That is, when the laser light L is made to enter from the outside into the liquid crystal layer 76 via the transparent substrate 79 and the transparent conductive film 78, to be reflected by the reflective film 74, and to exit from the liquid crystal layer 76 to the outside via the transparent conductive film 78 and the transparent substrate 79 in a state in which the modulation pattern is displayed in the liquid crystal layer 76, the laser light L is modulated in accordance with the modulation pattern displayed in the liquid crystal layer 76. In this way, according to the spatial light modulator 7, modulation (for example, modulation of the intensity, amplitude, phase, polarization, or the like of the laser light L) of the laser light L can be performed by appropriately setting the modulation pattern displayed in the liquid crystal layer 76. In addition, Figure 4 The modulation surface 7a illustrated is, for example, the liquid crystal layer 76.

[0056] Figure 4 is Figure 1 A schematic view of a 4f lens unit and a damper as illustrated in FIG. 6. As Figure 1 , 4As shown, the 4f lens unit 35 has a pair of lenses 35A, 35B arranged in order on the optical path of the laser light L from the spatial light modulator 7 toward the condenser lens 33. The pair of lenses 35A, 35B constitute a two-side telecentric optical system in which the modulation plane 7a of the spatial light modulator 7 and the entrance pupil plane (pupil plane) 33a of the condenser lens 33 are in an imaging relationship. Thereby, the image of the laser light L on the modulation plane 7a of the spatial light modulator 7 (the image of the laser light L modulated in the spatial light modulator 7) is transmitted (imaged) to the entrance pupil plane 33a of the condenser lens 33. Further, Fsin the figure indicates a Fourier plane.

[0057] Figure 5 is a schematic view for explaining the function of the damper shown in Figure 1 , 4 . As shown in Figure 1 , 4 , 5, the damper 36 is arranged between the spatial light modulator 7 and the condenser lens 33. More specifically, the damper 36 is arranged on the optical path of the laser light L between the lens 35A and the lens 35B (for example, on the Fourier plane F5). The damper 36 is used to block at least a part of the laser light L exiting from the spatial light modulator 7.

[0058] More specifically, as one example, in a case where the laser light L is branched into a plurality of beams of diffracted light by being modulated (diffracted) by displaying a modulation pattern including a diffraction grating pattern on the spatial light modulator 7 (example of (b) of Figure 5 ), the 0th-order diffracted light L0 (laser light L) is made to pass through the condenser lens 33 and the 1st-order diffracted light L1 is blocked so as not to reach the condenser lens 33. On the other hand, the damper 36 is configured to make substantially the entire laser light L to pass through the condenser lens 33 in a case where the laser light L is not diffracted (example of (a) of Figure 5 ).

[0059] Thus, in the laser processing apparatus 1, by controlling the modulation pattern displayed on the spatial light modulator 7, it is possible to switch between a state in which the entire laser light L passes through the damper 36 to be incident on the condenser lens 33 (state of (a) of Figure 5 ) and a state in which at least a part of the laser light L is blocked by the damper 36 to not be incident on the condenser lens 33 (state of (b) of Figure 5 ). As a result, in the laser processing apparatus 1, it is possible to adjust the output of the laser light L exiting from the condenser lens 33. That is, here, in addition to the attenuator 6, the spatial light modulator 7 (and the damper 36) also has a function for adjusting the output of the laser light L.

[0060] Further, in the attenuator 6, when a state in which the laser light L entirely transmits the polarizing plate 63 is taken as a reference, the output of the laser light L is attenuated by an amount corresponding to the driving amount of the λ / 2 wavelength plate 61. On the other hand, in the attenuator 6, when a state in which at least a part of the laser light L does not transmit the polarizing plate 63 is taken as a reference, a case in which the output of the laser light L is amplified by an amount corresponding to the driving amount of the λ / 2 wavelength plate 61 can also be assumed. Further, when a state in which the laser light L from the spatial light modulator 7 entirely enters the condenser lens 33 (for example, the state of (a) of FIG. 10) is taken as a reference, by being set to a state in which a part of the laser light L from the spatial light modulator 7 does not enter the condenser lens 33 (for example, the state of (b) of FIG. 10), the output of the laser light L is attenuated. Figure 5 Figure 5

[0061] On the other hand, when a state in which a part of the laser light L from the spatial light modulator 7 does not enter the condenser lens is taken as a reference, a case in which the output of the laser light L that enters the condenser lens 33 is amplified by controlling the modulation pattern displayed on the spatial light modulator 7 can also be assumed. Thus, in the present embodiment, adjusting the output of the laser light L can include both a case in which the output of the laser light L is attenuated and a case in which it is amplified. Likewise, the amount of adjustment of the output of the laser light L can include both an amount of attenuation and an amount of amplification of the output of the laser light L.

[0062] Here, a part of the laser light L that exits from the spatial light modulator 7 and passes through the 4f lens unit 35 and the damper 36 is reflected by the mirror 34 toward the condenser lens 33, and the remaining part of the laser light L transmits the mirror 34 to be incident to the camera 37. The camera 37 is a camera for taking an image of the laser light L on the entrance pupil plane 33a of the condenser lens 33. Thus, for example, a lens or the like that constitutes a telecentric optical system on both sides of the imaging plane of the camera 37 and the entrance pupil plane 33a of the condenser lens 33 is in an imaging relationship is provided in the front stage of the camera 37.

[0063] By this, the image of the laser light L on the entrance pupil plane 33a of the condenser lens 33 is imaged to the imaging plane of the camera 37. The image of the laser light L on the entrance pupil plane 33a of the condenser lens 33 is the image of the laser light L via the spatial light modulator 7. Thus, in the laser processing apparatus 1, it is possible to grasp the working state of the spatial light modulator 7 based on the imaging result of the camera 37.

[0064] ​​Next, one example of the process of the control section 50 for adjusting the output of the laser L in the laser processing apparatus 1 will be described. In the laser processing apparatus 1, as described above, the output of the laser L (hereinafter, referred to as "processing output") that exits from the condenser lens 33 can be adjusted by individually controlling the attenuator 6 and the spatial light modulator 7. That is, in the laser processing apparatus 1, the control section 50 performs a first adjustment process of adjusting the processing output by adjusting the modulation pattern displayed on the spatial light modulator 7, and a second adjustment process of adjusting the processing output by adjusting the drive amount of the λ / 2 wave plate 61 in the attenuator 6.

[0065] More specifically, the control section 50 adjusts the processing output in the first adjustment process by causing the modulation pattern including the adjustment pattern for modulating the laser L to be displayed on the spatial light modulator 7 in a manner that the amount of incidence of the laser L that exits from the spatial light modulator 7 and is incident to the condenser lens 33 varies, Figure 6 and Figure 7 is a schematic view that shows one example of the modulation pattern.

[0066] In the modulation pattern P0 shown in (a) of Figure 6 , the entire region of the modulation face 7a of the spatial light modulator 7 that corresponds to the entrance pupil face 33a of the condenser lens 33 (hereinafter, referred to as "incidence region") is set as a non-adjustment region Ra that does not include the adjustment pattern for varying the amount of incidence of the laser L to the condenser lens 33. That is, in a case where the laser L is modulated by the modulation pattern P0, as shown in (a) of Figure 5 , the entire laser L is incident to the condenser lens 33. In addition, the modulation pattern P0 (non-adjustment region Ra) can include an arbitrary pattern other than the adjustment pattern, like a pattern for correcting spherical aberration.

[0067] In the modulation pattern P1 shown in (b) of Figure 6 , the entire incidence region of the modulation face 7a of the spatial light modulator 7 is set as an adjustment region Rb that includes a diffraction grating pattern for branching the laser L into a plurality of beams of diffracted light as the adjustment pattern. In a case where the laser L is modulated with such a modulation pattern P1, as shown in (b) of Figure 5 , only the diffracted light of the number (0th order) of times of a part of the laser L is incident to the condenser lens 33. That is, in this case, the amount of incidence of the laser L to the condenser lens 33 is reduced compared to the case where the modulation pattern P0 is used, and the processing output is attenuated.

[0068] In addition, for the modulation pattern P1 (adjustment region Rb), an arbitrary pattern other than the adjustment pattern such as a pattern for correcting spherical aberration can also be included. Furthermore, the ratio of the diffracted light of each order can also be adjusted by adjusting the luminance values of the diffraction grating pattern on the modulation surface 7a of the spatial light modulator 7. That is, the control section 5 can adjust the amount of laser light L incident on the condenser lens 33, and further adjust the machining output, by adjusting the luminance values of the diffraction grating pattern displayed on the modulation surface 7a.

[0069] In Figure 7 In the modulation patterns P2, P3 shown in FIG. 6, a portion of the incident region of the modulation surface 7a of the spatial light modulator 7 is set as the non-adjustment region Ra, and another portion of the incident region is set as the adjustment region Rb. Specifically, Figure 7 The modulation pattern P2 shown in (a) of FIG. 6 includes a slit-shaped non-adjustment region Ra provided in the central portion of the incident region, and a slit pattern provided in the outer portion of the incident region in such a manner as to straddle the non-adjustment region Ra as the adjustment pattern. Thereby, the portion of the laser light L incident on the non-adjustment region Ra (slit) is not diffracted and is incident on the condenser lens 33 via the damper 36.

[0070] On the other hand, the portion of the laser light L incident on the adjustment region Rb is diffracted and blocked by the damper 36, and is not incident on the condenser lens 33. That is, the amount of laser light L incident on the condenser lens 33 is also reduced in this case compared to the case where the modulation pattern P0 is used, and the machining output is attenuated. In particular, in the modulation pattern P2, the amount of laser light L incident on the condenser lens 33 can be adjusted, and further the machining output can be adjusted, by adjusting the width (slit width W) of the non-adjustment region Ra.

[0071] Figure 7 The modulation pattern P3 shown in (b) of FIG. 6 includes an adjustment pattern in which a circular adjustment region Rb is provided in the central portion of the incident region, and a circular ring-shaped non-adjustment region Ra is provided in such a manner as to surround the adjustment region Rb. In this modulation pattern P3 as well, the amount of laser light L incident on the condenser lens 33 is reduced, and the machining output is attenuated, as with the modulation pattern P2. Furthermore, in the modulation pattern P3, the amount of laser light L incident on the condenser lens 33 can be adjusted, and further the machining output can be adjusted, by adjusting the size of the adjustment region Rb.

[0072] Thus, in the first adjustment process, the control section 50 can adjust the machining output, which is the output of the laser light L emitted from the condenser lens 33, by causing the above-described modulation patterns P1 to P3, which include the adjustment pattern for modulating the laser light L, to be displayed on the spatial light modulator 7 in such a manner that the amount of laser light L incident on the condenser lens 33 varies.

[0073] On the other hand, the control section 50 adjusts the output of the laser L in the second adjustment process in such a manner that the output of the laser processing and the adjustment amount in the above first adjustment process are combined to become a target value at the time of the laser processing. Thereby, by the combination of the first adjustment process and the second adjustment process, the output of the laser processing is adjusted to the target value, and the laser processing at the appropriate output is performed.

[0074] Next, one example of the laser processing method including the above output adjustment process will be described. Figure 8 is a flowchart showing one example of the laser processing method. Here, as shown in Figure 9 , first, the object 11 is prepared. The object 11 is supported on the stage 20 with the first surface 11a facing the condenser lens 33 side. Thus, here, the first surface 11a becomes the incident surface of the laser L in the object 11.

[0075] Further, here, for one line A, the laser processing is performed at two different positions Zl, Z2 in the Z direction. The Z direction is the direction from the second surface lib of the object 11 toward the first surface 11a, and the position Z2 is a position closer to the first surface 11a side as the incident surface of the laser L than the position Zl. In this laser processing method, as described later, the control section 50 performs a first processing process that relatively moves the condensing point C with respect to the object 11 in the negative direction of the X by moving the stage 20 in the positive direction of the X in a state where the condensing point C is aligned with the position Zl, and forms the modified region 12 along the line A at the position Zl.

[0076] Then, the control section 50 performs a second processing process that relatively moves the condensing point C with respect to the object 11 in the positive direction of the X by moving the stage 20 in the negative direction of the X in a state where the condensing point is aligned with the position Z2, and forms the modified region 12 along the line A at the position Z2. In other words, here, the reciprocating processing on a plurality of paths is performed. The processing at the position Zl is taken as a path PTl (outbound), and the processing at the position Z2 is taken as a path PT2 (return). Further, here, the processing output of the laser L on the path PT2 is set to be smaller than the processing output of the laser L on the path PTl. Therefore, in order to attenuate the processing output of the laser L at least between the path PTl and the path PT2, the control section 50 performs the above first adjustment process and the second adjustment process. Hereinafter, each process will be described in detail.

[0077] As shown in Figure 8As shown, in the laser processing method, first, the control section 50 receives selection of processing conditions (step S1), for example, using the input receiving section. The processing conditions are, for example, the number of paths, the positions in the Z direction of each path, the target values of the processing output on each path, and the like. Here, as described above, the processing conditions of the number of paths being 2, the positions in the Z direction of each of the paths PT1, PT2 being positions Z1, Z2, the target value of the processing output on the path PT1 being 5W, and the target value of the processing output on the path PT2 being 1W are selected.

[0078] Next, the control section 50 calculates the output difference between the target value of the processing output on the path PT1 and the target value of the processing output on the path PT2 based on the processing conditions selected in step S1 (step S2: calculation processing). Here, the target value of the processing output on the path PT1 is 5W, and the target value of the processing output on the path PT2 is 1W, so the output difference is 4W. In other words, in this step S2, the control section 50 performs calculation processing of calculating the output difference (4W) between the target value of the processing output on the first processing (path PT1) (5W) and the target value of the processing output on the second processing (path PT2) (1W).

[0079] Next, the control section 50 selects an adjustment pattern corresponding to the output difference calculated in step S2 (step S3: selection processing). A more specific description of this step S3 will be given. Here, the control section 50 holds a table in which a plurality of adjustment patterns that differ in the adjustment amount of the output are associated with control values for displaying each adjustment pattern on the spatial light modulator 7. As one example of such a table, there is a table in which, as shown in (b) of FIG. 9, in the case where the entire of the incident region of the diffractive grating pattern as the adjustment pattern contains a diffractive grating pattern different in the balance between the 0th-order diffracted light and the 1st-order diffracted light due to the tuning value, a plurality of diffractive grating patterns and the tuning value of each diffractive grating pattern are associated. Figure 6

[0080] [One Example of a Table]

[0081]

[0082]

[0083] In this case, for example, in the case where the control section 50 causes the modulation pattern containing the diffractive grating pattern with the tuning value of 32 to be displayed on the spatial light modulator 7, the laser L passing through the spatial light modulator 7 is branched into the 0th-order diffracted light of 90% of the output and the 1st-order diffracted light of 10% of the output. Then, the 1st-order diffracted light is blocked by the damper 36, and only the 0th-order diffracted light enters the condenser lens 33 via the damper 36, whereby the processing output is attenuated by about 10% as a result. Here, the adjustment amount is the attenuation amount, and the control value is the tuning value.​

[0084] As described above, in a case where the target value of the machining output on the path PT1 is 5W, the target value of the machining output on the path PT2 is 1W, and the output difference is 4W, for example, the control section 50 can cause the machining output to attenuate by about 70% to about 1.7W by causing the modulation pattern including the diffraction grating pattern of the 128th harmonic value to be displayed on the spatial light modulator 7. In this way, the control section 50 performs a selection process of selecting the adjustment pattern that becomes the adjustment amount corresponding to the output difference calculated in the calculation process from among the plurality of adjustment patterns (diffraction grating patterns) that differ in adjustment amount (attenuation amount). In addition, here, the control section 50 selects the diffraction grating pattern that becomes the attenuation amount closest to the output difference calculated in the calculation process from among the plurality of diffraction grating patterns shown in the above table in a range where the attenuated machining output is not less than the machining output on the path PT2 (1W).

[0085] Next, the control section 50 performs adjustment of the attenuator 6 (process S4: acquisition process). More specifically, in process S4, the control section 50 monitors the machining output, for example, by inputting the output signal of the power meter disposed directly below the condenser lens 33. In this state, the control section 50 drives the λ / 2 wavelength plate 61 by controlling the rotation stage 62 of the attenuator 6, and adjusts the machining output. Thereby, the control section 50 can acquire the drive amount of the λ / 2 wavelength plate 61 in which the machining output becomes the target value.

[0086] More specifically, the control section 50 first monitors the machining output and drives the λ / 2 wavelength plate 61 in a state where the modulation pattern used for the path PT1 (for example, the modulation pattern P0 that does not include the adjustment pattern) is displayed on the spatial light modulator 7, and thereby acquires the drive amount of the λ / 2 wavelength plate 61 in which the machining output becomes the target value of the path PT1, that is, 5W.

[0087] In conjunction therewith, the control section 50 monitors the machining output and drives the λ / 2 wavelength plate 61 in a state where the modulation pattern used for the path PT2 (for example, the modulation pattern P1 in which the diffraction grating pattern of the 128th harmonic value is set to the entire incident region as the adjustment pattern) is displayed on the spatial light modulator 7, and thereby acquires the drive amount of the λ / 2 wavelength plate 61 in which the machining output becomes the target value of the path PT2, that is, 1W. In the above example, the machining output is caused to attenuate by about 70% to about 1.7W by causing the modulation pattern including the diffraction grating pattern of the 128th harmonic value to be displayed on the spatial light modulator 7. Therefore, here, the drive amount of the λ / 2 wavelength plate 61 that achieves the attenuation amount of the amount of difference from the target value, that is, 0.7W, is acquired.

[0088] Thus, here, the control section 50 monitors the machining output while the modulation pattern including the adjustment pattern (the 1st pattern) selected in the process S3 is displayed on the spatial light modulator 7 and drives the λ / 2 wavelength plate 61, and acquires the driving amount of the λ / 2 wavelength plate 61 in which the machining output becomes the target value in the path PT2, in addition to the driving amount of the λ / 2 wavelength plate 61 for the path PT1.

[0089] By the above processes, the calibration of the adjustment processing of the machining output at the time of laser machining is completed. That is, the control section 50 performs the calibration processing including the following processes: the calculation processing (process S2) of calculating the output difference between the target value in the 1st machining processing (path PT1) and the target value in the 2nd machining processing (path PT2); the selection processing (process S3) of selecting the adjustment pattern in which the adjustment amount differs from the adjustment amounts of the plurality of adjustment patterns (diffraction grating patterns) from among the plurality of adjustment patterns, as the adjustment pattern in which the adjustment amount corresponds to the output difference calculated in the calculation processing; and the acquisition processing (process S4) of acquiring the driving amount of the λ / 2 wavelength plate 61 in which the machining output becomes the target value in the 2nd machining processing, after the selection processing, while the modulation pattern including the adjustment pattern is displayed on the spatial light modulator 7 and the λ / 2 wavelength plate 61 is driven so that the machining output is monitored.

[0090] In the following process, the control section 50 performs laser machining of the object 11 by controlling the light source 10, the laser irradiation section 30, and the moving section 40 (process S5: 1st machining processing). The process S5 is described in more detail. Figure 10 is a schematic view for explaining the process of performing laser machining. As shown in Figure 10 , in the process S5, first, the control section 50 performs the 1st machining processing (path PT1) of relatively moving the condensing point C of the laser L aligned to the position Z1 in the X negative direction (1st direction) along the line A by controlling the moving section 40, and scanning the laser L to the object 11 to perform laser machining of forming the modified region 12A on the object 11.

[0091] More specifically, in the 1st machining processing, as shown in Figure 10 (a), the control section 50 moves at least one of the stage 20 and the laser irradiation section 30 in the Z direction by controlling the moving section 40, in such a manner that the position of the condensing point C of the laser L in the Z direction becomes the position Z1 inside the object 11. In this state, the control section 50 moves the stage 20 in the X positive direction by controlling the moving section 40.

[0092] Thus, as shown in Figure 10(a) and (b) of FIG. 10, the condensing point C of the laser L is relatively moved in the X negative direction with respect to the object 11. As a result, the condensing point C enters the inside of the object 11 from the outer edge in the X positive direction of the object 11, and the condensing point C travels in the inside of the object 11, and the irradiation of the laser L along the line A is performed. Thus, at the position Zl, the modified region 12A is formed in the object 11 along the line A. Further, as shown in Figure 10 (c) of FIG. 10, the control section 50 controls the moving section 40 to continue the relative movement of the condensing point C, and thus the condensing point C exits to the outside of the object 11 from the outer edge in the X negative direction of the object 11, and the first processing (the path PT1) ends. Then, the control section 50 stops the stage 20 by the control of the moving section 40.

[0093] Further, before the first processing, the control section 50 drives the λ / 2 wavelength plate 61 in accordance with the driving amount of the λ / 2 wavelength plate 61 acquired in the process S4 in such a manner that the processing output of the laser L becomes the target value (5 W in this case) of the path PT1. In conjunction with this, the control section 50 displays the modulation pattern (for example, the modulation pattern P0 which does not include the adjustment pattern) for the path PT1 on the spatial light modulator 7. The control of these attenuators 6 and the spatial light modulator 7 can be performed before the condensing point C starts the relative movement, or can be performed between the start of the relative movement of the condensing point C and the entry of the condensing point C into the inside of the object 11.

[0094] In the following process, after the process S6 described below is performed, the control section 50 performs the laser processing of the object 11 (process S7: second processing) by controlling the light source 10, the laser irradiation section 30, and the moving section 40. The process S7 is described more specifically. Figure 11 is a schematic view for explaining the process of performing the laser processing. As shown in Figure 11 In the process S7, first, the control section 50 performs the second processing (the path PT2) which relatively moves the condensing point C of the laser L which is aligned to the position Z2 in the X positive direction (the second direction) along the line A by controlling the moving section 40, and scans the laser L to the object 11 to perform the laser processing of forming the modified region 12B in the object 11.

[0095] More specifically, in the process S7, as shown in Figure 11 (a), the control section 50 controls the moving section 40 so that at least one of the stage 20 and the laser irradiation section 30 is moved in the Z direction in such a manner that the position of the condensing point C of the laser L in the Z direction becomes the position Z2 in the object 11. In this state, the control section 50 moves the stage 20 in the X negative direction by controlling the moving section 40.

[0096] Thus, as shown in Figure 11As shown in (a) and (b), the condensing point C of the laser L is relatively moved in the X positive direction (2nd direction) with respect to the object 11. As a result, the condensing point C enters the inside of the object 11 from the outer edge of the object 11 in the X negative direction, and the condensing point C travels inside the object 11, and irradiation of the laser L along the line A is performed. Thus, at the position Z2, a modified region 12B is formed along the line A in the object 11. Further, as shown in (c), the control section 50 causes the condensing point C to exit to the outside of the object 11 from the outer edge of the object 11 in the X positive direction by relatively moving the condensing point C by controlling the moving section 40, and the 2nd processing is ended. Then, the control section 50 stops the stage 20 by the control of the moving section 40. Figure 11

[0097] Here, between the process S5 and the process S7, that is, between the 1st processing and the 2nd processing, an adjustment processing of the output of the laser L is performed (process S6: 1st adjustment processing, 2nd adjustment processing). More specifically, in the process S6, the control section 50 performs the 1st adjustment processing of adjusting the processing output by displaying the modulation pattern (modulation pattern for the path PT2, that is, for example, the modulation pattern Pl including the diffraction grating pattern as the adjustment pattern) including the adjustment pattern for modulating the laser L to the spatial light modulator 7 in such a manner that the amount of incidence of the laser L emitted from the spatial light modulator 7 and incident to the condensing lens 33 is varied.

[0098] Here, the control section 50 causes the modulation pattern including the adjustment pattern selected in the selection processing (process S3) of the above-described calibration processing to be displayed to the spatial light modulator 7. As one example, the adjustment pattern is a pattern for attenuating the processing output of the laser L from the target value (5W) of the processing output of the path PT1 to the target value (1W) of the processing output of the path PT2.

[0099] In conjunction therewith, the control section 50 performs the 2nd adjustment processing of adjusting the processing output of the laser L by driving the λ / 2 wavelength plate 61 in such a manner that the processing output of the laser L and the adjustment amount in the 1st adjustment processing are combined to become the target value of the processing output of the path PT2. Here, the control section 50 drives the λ / 2 wavelength plate 61 in accordance with the driving amount acquired in the acquisition processing (process S4) of the above-described calibration processing. Here, the driving amount of the λ / 2 wavelength plate 61 is a driving amount for attenuating the processing output to the target value (1W) of the path PT2 in combination with the attenuation amount in the 1st adjustment processing. Thus, in a state where the processing output of the laser L is adjusted (attenuated) to an appropriate value, the above-described process S7 is performed. That is, in the process S7, the control section 50 performs the laser processing processing of performing the laser processing using the output adjusted laser L after the 1st adjustment processing and the 2nd adjustment processing.

[0100] ​Further, the first adjustment process and the second adjustment process can be implemented at least partially in repetition with each other. As one example, the control section 50 can start the first adjustment process and the second adjustment process at the same time. Further, the first adjustment process and the second adjustment process can be executed at an arbitrary time point between when the condensing point C exits to the outside of the object 11 in the process S5, that is, until when the condensing point C enters the inside of the object 11 in the process S7. As one example, the control section 50 can cause the first adjustment process and the second adjustment process to start at the time point when the condensing point C exits from the object 11 in the process S5. Thereby, the time in which the first adjustment process and the second adjustment process are involved can be maximized in repetition with the time in which the acceleration and deceleration of the relative movement of the condensing point C are involved.

[0101] As explained above, in the laser processing apparatus 1, the laser L emitted from the light source 10 is incident to the condensing lens 33 via the attenuator 6, and condensed by the condensing lens 33 toward the object 11. Thus, the output of the laser L irradiated toward the object 11 can be adjusted by adjusting the drive amount of the λ / 2 wavelength plate 61 of the attenuator 6. Further, in the present laser processing apparatus 1, the laser L is incident to the condensing lens 33 via the spatial light modulator 7. Thus, the output of the laser L can be further adjusted by controlling the modulation pattern of the spatial light modulator 7.

[0102] More specifically, in the laser processing apparatus 1, the control section 50 executes the first adjustment process and the second adjustment process, the first adjustment process adjusts the processing output which is the output of the laser L emitted from the condensing lens 33 by causing the spatial light modulator 7 to display a modulation pattern including an adjustment pattern for modulating the laser L in a manner that the amount of incidence of the laser L to the condensing lens 33 varies, and the second adjustment process adjusts the output of the laser L by driving the λ / 2 wavelength plate 61 in a manner that the processing output and the adjustment amount in the first adjustment process together become a target value at the time of laser processing.

[0103] Thus, in the laser processing apparatus 1, the adjustment of the output of the laser L is performed using both of the attenuator 6 and the spatial light modulator 7. Thereby, compared with the case where only the attenuator 6 is used, the adjustment amount of the attenuator 6 is reduced, the amount of the burden of the spatial light modulator 7 in the adjustment amount targeted as a target is reduced, and the drive amount of the λ / 2 wavelength plate 61 is reduced. Thus, the time until the drive amount of the λ / 2 wavelength plate 61 reaches the necessary amount is shortened, and as a result, the time involved in the adjustment of the output of the laser L can be shortened. Further, because the drive amount of the λ / 2 wavelength plate 61 is reduced, the loss of the device such as the rotary stage 62 which mechanically drives the λ / 2 wavelength plate 61 can be suppressed.

[0104] Further, the laser processing apparatus 1 includes a moving section 40 that moves at least one of the stage 20 and the laser irradiation section 30 in a manner that the condensing point C of the laser L with respect to the object 11 relatively moves. Then, the control section 50 performs a first processing (path PT1) of performing laser processing of the object 11 by scanning the laser L with respect to the object 11 by relatively moving the condensing point C in the negative direction of X by controlling the moving section 40, and a second processing (path PT2) of performing laser processing of the object 11 by scanning the laser L with respect to the object 11 by relatively moving the condensing point C in the positive direction of X by controlling the moving section 40 after the first processing. Then, the control section 50 performs a first adjustment processing and a second adjustment processing between the first processing and the second processing.

[0105] In a case where such reciprocating processing of scanning the laser L in one direction (outward journey) and scanning the laser L in the opposite direction (return journey) is performed, that is, in a case where adjustment of the output of the laser L is performed between the outward journey and the return journey, if the time involved in the adjustment becomes longer, the waiting time between the outward journey and the return journey becomes longer, and the time involved in the entire laser processing becomes longer. Thus, in this case, if the time involved in the adjustment of the output of the laser L is shortened as described above, the waiting time between the outward journey and the return journey is reduced and the time involved in the entire laser processing is shortened. That is, in a case where such reciprocating processing is performed, it is particularly effective to shorten the time involved in the adjustment of the output of the laser L.

[0106] Further, in the laser processing apparatus 1, the control section 50 performs a calibration processing including a calculation processing of calculating an output difference between the target value in the first processing and the target value in the second processing, a selection processing of selecting an adjustment pattern that becomes an adjustment amount corresponding to the output difference calculated in the calculation processing from among a plurality of adjustment patterns different in adjustment amount, and a retrieval processing of, after the selection processing, monitoring the processing output and driving the λ / 2 wave plate 61 in a state where the modulation pattern including the adjustment pattern selected in the selection processing is displayed on the spatial light modulator 7, thereby retrieving the driving amount of the λ / 2 wave plate 61 where the processing output becomes the target value in the second processing, before the first adjustment processing and the second adjustment processing. By performing such calibration before the first adjustment processing and the second adjustment processing, adjustment of the output of the laser L can be performed more correctly and quickly in the first adjustment processing and the second adjustment processing.

[0107] Further, in the laser processing apparatus 1, the control section 50 retains a table that associates each of a plurality of adjustment patterns different in adjustment amount with a control value for displaying each adjustment pattern on the spatial light modulator 7, and in the selection processing, selects an adjustment pattern that becomes an adjustment amount corresponding to the output difference calculated in the calculation processing by referring to the table. Thus, the calibration processing can be performed quickly.

[0108] Furthermore, in the laser processing apparatus 1, the control unit 50 moves the focusing point C relative to the object 11 in the negative X direction through the first processing step, and starts the first adjustment process and the second adjustment process at the point when the focusing point C deviates from the object 11. Therefore, by repeating the time involved in the first and second adjustment processes with the time between the focusing point C exiting the object 11 and the relative movement of the focusing point C stopping, the waiting time between the outgoing and returning strokes in reciprocating processing can be further reduced.

[0109] Furthermore, the laser processing apparatus 1 includes a damper 36 disposed between the spatial light modulator 7 and the condenser lens 33, for blocking at least a portion of the laser L emitted from the spatial light modulator 7. Thus, in the first adjustment process, the control unit 50 displays a modulation pattern, including a diffraction grating pattern for branching the laser L into multiple diffracted beams, as an adjustment pattern on the spatial light modulator 7, and modulates the laser L such that the first diffracted beam among the multiple diffracted beams is blocked by the damper 36 and does not incident on the condenser lens 33. Therefore, the output of the laser L can be easily and reliably adjusted using the spatial light modulator 7.

[0110] The above embodiments illustrate one aspect of the present invention. Therefore, the present invention is not limited to the above embodiments and can be implemented in any modified manner.

[0111] [First Variation]

[0112] For example, in Figure 8 In the laser processing method of the above-described embodiment, it is exemplified that in the first adjustment process, a method comprising... Figure 6 In the case of (b) where the diffraction grating pattern is set as the modulation pattern P1 of the overall adjustment pattern of the incident region, the adjustment pattern can be set as shown in the first adjustment process. Figure 7 As in (a), a modulation pattern P2 is used as the adjustment pattern, comprising a slit pattern in which a diffraction grating pattern is set in a portion of the incident region to form a slit. When using modulation pattern P1, in the selection process, a diffraction grating pattern that is the appropriate adjustment amount is selected from among a plurality of diffraction grating patterns with different harmonic values, which are control values. On the other hand, for example, when using... Figure 7 In the case of modulation pattern P2 in (a), during the selection process, it is possible to select a slit pattern with a suitable adjustment amount from multiple slit patterns with different slit widths W as control values.

[0113] Figure 12 This is a flowchart illustrating a laser processing method under such circumstances. For example... Figure 12 As shown, the laser processing method of the first modified example is the same as... Figure 8The laser processing method shown differs from the comparative example mainly in that the process S8 is included between the process S1 and the process S2. The process S8 will be described in detail. In the process S8, the control section 50 acquires a table in which each of a plurality of slit patterns having different adjustment amounts is associated with a control value (slit width W) for displaying each slit pattern on the spatial light modulator 7.

[0114] Therefore, the control section 50 monitors the processing output by, for example, inputting an output signal of a power meter disposed directly below the condenser lens 33 while changing the slit width W of the slit pattern displayed on the spatial light modulator 7. Thus, the control section 50 acquires a table in which each of a plurality of slit widths W is associated with the processing output of the laser L at each slit width W. One example of such a table is shown below. Note that the values of the processing output in the table below are values in the case where the processing output when the entire laser L passes through the damper 36 is taken as 100.

[0115]

[0116] In this case, for example, when the control section 50 causes the modulation pattern P2 including the slit pattern having a slit width W of 100 to be displayed on the spatial light modulator 7, 90% of the laser L passing through the spatial light modulator 7 is made incident on the condenser lens 33 via the damper 36, and 10% is blocked by the damper 36. As a result, the processing output is attenuated by about 10%. Thus, for example, when the target value of the processing output in the path PT1 is 5W and the target value of the processing output in the path PT2 is 1W, and the output difference is 4W, as shown in the above embodiment, the control section 50 can cause the processing output to be attenuated by about 70%, to about 1.7W, for example, by selecting a slit pattern having a slit width W of 40 and causing the modulation pattern P2 to be displayed on the spatial light modulator 7.

[0117] In the case where the slit pattern in which the diffraction grating pattern is set in part of the incident region of the modulation surface 7a of the spatial light modulator 7 is used as described above, the degree of freedom in setting the beam shape is easily ensured compared to the case where the diffraction grating pattern is set in the entire incident region, and the beam shape can be controlled to be elliptical, for example. On the other hand, in the case where the diffraction grating pattern is set in the entire incident region, the beam quality becomes good.

[0118] [2nd Modification Example]

[0119] Here, Figure 13 (a) of FIG. 12 is a view of a modulation pattern P4 displayed on the modulation surface 7a of the spatial light modulator 7. The modulation pattern P4 includes a mark 7M displayed outside the incident region on the modulation surface 7a of the spatial light modulator 7. The shape of the mark 7M is arbitrary, but is a two-dimensional grating shape in this case. Figure 13(b) is an image 70 of the laser L acquired by camera 37. Camera 37 forms an image of the laser L transmitted via spatial light modulator 7. Therefore, when spatial light modulator 7 displays a modulation pattern P4 containing the mark 7M, an image 70M corresponding to the mark 7M is also generated in image 70. Thus, by comparing the modulation pattern P4 and image 70, it is possible to determine whether the modulation pattern P4 is correctly displayed in spatial light modulator 7, that is, whether spatial light modulator 7 is working properly.

[0120] Therefore, in the laser processing apparatus 1 of this modified example, the control unit 50 performs a judgment process based on comparing the image 70 of the laser L emitted from the spatial light modulator 7 with the mark 7M of the modulation pattern P4 to determine the operating state of the spatial light modulator 7. In this judgment process, the control unit 50 can determine that the spatial light modulator 7 is operating normally if the image 70 (image 70M) matches the mark 7M, and determine that the spatial light modulator 7 is operating abnormally if the image 70 (image 70M) does not match the mark 7M.

[0121] Here, in the above embodiment, at least a portion of the first adjustment process using the spatial light modulator 7 and the second adjustment process using the attenuator 6 are repeated, and an example is described starting at the time point when the focus point C deviates from the object 11.

[0122] However, even without performing the first adjustment process, if only the attenuator 6 is used to adjust the processing output of laser L, the standby time during reciprocating processing can be reduced by performing the adjustment at the same time point. That is, when only the attenuator 6 is used to adjust the processing output of laser L, although the time involved in adjusting the processing output is longer compared to the case where attenuator 6 and spatial light modulator 7 are used together as in the above embodiment, the standby time during reciprocating processing can be reduced by repeating the time involved in adjusting the processing output with the time involved in the acceleration and deceleration of the focusing point C.

[0123] Figure 14 (a) through (e) are diagrams representing a series of actions in this situation. For example... Figure 14 As shown in (a), by moving the platform 20 holding the object 11 in the positive X direction, the focusing point C is moved relatively in the negative X direction, entering the interior of the object 11 from its outer edge in the positive X direction (the first processing is started). Then, as... Figure 14As shown in (b), the relative movement of the condensing point C progresses, and the condensing point C reaches the outer edge of the object 11 in the X negative direction and exits from the object 11 (end of the first processing). At this time, the control section 50 acquires a signal indicating that the condensing point C has exited from the object 11. This signal can be either a signal from the first unit 41 of the moving section 40 indicating the amount of movement of the stage 20 or a signal from an AF unit that acquires the displacement of the incident surface (first surface 11a) of the object 11.

[0124] When the signal indicating that the condensing point C has exited from the object 11 is input, the control section 50 starts adjustment of the processing output by driving the λ / 2 wavelength plate 61 by controlling the rotating stage 62 of the attenuator 6. That is, the control section 50 starts the adjustment processing of the processing output by the attenuator 6 at the time point at which the condensing point C has exited from the object 11. For example, in a case where the target value of the processing output in the first processing is 5 W and the target value of the processing in the second processing that follows is 1 W, the control section 50 drives the λ / 2 wavelength plate 61 in such a manner that the processing output is attenuated by an output difference of 4 W.

[0125] At the same time as this, as shown in (c), after the relative movement of the condensing point C is stopped, the condensing point C starts to relatively move in the X positive direction by moving the stage 20 in the X negative direction. Figure 14 Figure 14 As shown in (d), the condensing point C enters the inside of the object 11 from the outer edge of the object 11 in the X negative direction (start of the second processing). Then, as shown in (e), the relative movement of the condensing point C progresses, and the condensing point C reaches the outer edge of the object 11 in the X positive direction and exits from the object 11 (end of the second processing). At this time, the control section 50 acquires a signal indicating that the condensing point C has exited from the object 11. Then, when further processing is performed, adjustment of the processing at this time point is further performed. Figure 14

[0126] By repeating the time involved in the adjustment processing of the processing output using the attenuator 6 and the time until the condensing point C exits from the object 11 and the relative movement of the condensing point C is stopped as described above, the waiting time between the outward journey and the return journey in the reciprocating processing can be further reduced.

[0127] ​​For the laser processing apparatus in this case, the following notes are made. A laser processing apparatus including: a support section for supporting an object; a light source for emitting a laser; a laser irradiation section for irradiating the laser emitted from the light source toward the object supported by the support section; and a control section for performing laser processing of the object by controlling at least the laser irradiation section, the laser irradiation section having: an attenuator for adjusting the output of the laser emitted from the light source by an adjustment amount corresponding to a drive amount of a wavelength plate and emitting; and a condenser lens for condensing the laser emitted from the attenuator toward the object supported by the support section, the control section performing: adjustment processing for adjusting the output of the laser emitted from the condenser lens, i.e., a processing output, so that the processing output becomes a target value at the time of laser processing; and laser processing processing for performing the laser processing by outputting the laser whose output has been adjusted after the adjustment processing.

[0128] [Other modifications]

[0129] In the above example, the case where a straight line A is set for the object 11 and processing is performed on this line A in two paths PT1, PT2 of two positions Z1, Z2 is explained. However, the line A may, for example, also be set to a circular shape concentric with the outer edge of the object 11, and processing in one or more arbitrary path numbers in the Z direction can also be performed. Furthermore, as explained above, in the case where the damper 36 blocks a high-output light beam that is part of the laser L, a cooling section for cooling the damper 36 can be provided. As for the cooling method of the cooling section, any method such as water cooling or air cooling can be adopted.

Claims

1. A laser processing apparatus characterized by comprising: a support section for supporting an object; a light source for emitting a laser light; a laser light irradiation section for irradiating the laser light emitted from the light source toward the object supported by the support section; and a control section for performing laser processing of the object by controlling at least the laser light irradiation section, the laser light irradiation section has: an attenuator for adjusting and emitting an output of the laser light emitted from the light source in accordance with an adjustment amount corresponding to a drive amount of a wavelength plate; a spatial light modulator for modulating and emitting the laser light emitted from the attenuator in accordance with a modulation pattern; and a condensing lens for condensing the laser light emitted from the spatial light modulator toward the object supported by the support section, the control section performs: a first adjustment process for adjusting a processing output that is an output of the laser light emitted from the condensing lens by causing the spatial light modulator to display the modulation pattern including an adjustment pattern for modulating the laser light in a manner that an amount of incidence of the laser light emitted from the spatial light modulator and incident on the condensing lens varies; a second adjustment process for adjusting the output of the laser light by driving the wavelength plate in a manner that the processing output and an adjustment amount in the first adjustment process together become a target value at the time of laser processing; and a laser processing process for performing the laser processing by outputting the laser light after the first adjustment process and the second adjustment process.

2. The laser processing apparatus according to claim 1, characterized by: a moving section for moving at least one of the support section and the laser light irradiation section in a manner that a condensing point of the laser light of the object moves relatively with respect to the object, comprising: the control section performs a first processing process and a second processing process, and performs the first adjustment process and the second adjustment process between the first processing process and the second processing process, the first processing process is a process for performing laser processing of the object by controlling the moving section to relatively move the condensing point in a first direction and scan the laser light toward the object, the second processing process is a process for performing laser processing of the object by controlling the moving section to relatively move the condensing point in a second direction opposite to the first direction and scan the laser light toward the object after the first processing process as the laser processing process.

3. The laser processing apparatus according to claim 2, characterized by: the control section performs a calibration process including a calculation process, a selection process, and an acquisition process before the first adjustment process and the second adjustment process, the calculation process is a process for calculating an output difference of the target value in the first processing process and the target value in the second processing process, the selection process is a process for selecting the adjustment pattern that becomes an adjustment amount corresponding to the output difference calculated in the calculation process from a plurality of adjustment patterns different in adjustment amount, ​ The acquisition process is a process of acquiring, after the selection process, a driving amount of the wavelength plate at which the machining output becomes the target value in the second machining process, by monitoring the machining output and driving the wavelength plate, in a state in which the modulation pattern including the adjustment pattern selected in the selection process is displayed on the spatial light modulator.

4. The laser machining device according to claim 3, wherein The control section retains a table in which each of a plurality of adjustment patterns different in adjustment amount is associated with a control value for displaying each adjustment pattern on the spatial light modulator, and in the selection process, selects the adjustment pattern that becomes the adjustment amount corresponding to the output difference calculated in the calculation process, by referring to the table.

5. The laser machining device according to claim 2, wherein The control section relatively moves the focal point to the first direction by the first machining process, and starts the first adjustment process and the second adjustment process at a time point at which the focal point exits from the object.

6. The laser machining device according to claim 3, wherein The control section relatively moves the focal point to the first direction by the first machining process, and starts the first adjustment process and the second adjustment process at a time point at which the focal point exits from the object.

7. The laser machining device according to claim 4, wherein The control section relatively moves the focal point to the first direction by the first machining process, and starts the first adjustment process and the second adjustment process at a time point at which the focal point exits from the object.

8. The laser machining device according to any one of claims 1 to 7, wherein a damper configured between the spatial light modulator and the condenser lens for shielding at least a part of the laser light emitted from the spatial light modulator, includes: The control section modulates the laser light in the first adjustment process by causing the modulation pattern including a diffraction grating pattern for branching the laser light into a plurality of beams of diffracted light as the adjustment pattern to be displayed on the spatial light modulator, in a manner that a number of times of diffraction of a part of the plurality of beams of diffracted light is shielded by the damper and does not enter the condenser lens.

9. The laser machining device according to any one of claims 1 to 7, wherein the modulation pattern includes a mark displayed outside a region of the spatial light modulator corresponding to a pupil plane of the condenser lens, The control section performs a judgment process of judging an operating state of the spatial light modulator based on a comparison of an image of the laser light emitted from the spatial light modulator and the mark.

10. The laser machining device according to claim 8, wherein the modulation pattern includes a mark displayed outside a region of the spatial light modulator corresponding to a pupil plane of the condenser lens, The control section performs a judgment process of judging an operating state of the spatial light modulator based on a comparison of an image of the laser light emitted from the spatial light modulator and the mark. ​ ​ The control section performs a determination process of determining the operation state of the spatial light modulator based on a comparison between an image of the laser light emitted from the spatial light modulator and the mark. The control section performs a determination process of determining the operation state of the spatial light modulator based on a comparison between an image of the laser light emitted from the spatial light modulator and the mark.

Images