JP2015074019A - Laser processing method and manufacturing method for inkjet head - Google Patents

Abstract

Provided is a laser processing method excellent in energy utilization efficiency, and an ink jet head using the laser processing method. A laser beam is split into a first laser beam and a second laser beam having energy smaller than that of the first laser beam, the first laser beam is irradiated to a first processing point, and then the laser beam is irradiated to the first laser beam. A third laser beam having a lower energy than that of one laser beam and a fourth laser beam having a higher energy than that of the third laser beam are branched to irradiate the first laser beam on the first processing point after the first laser beam is irradiated. At the same time, the second laser beam 26 is irradiated onto the second processing point 26, and then the laser beam is branched into a fifth laser beam, a fourth laser beam, and a sixth laser beam having an energy smaller than that of the fifth laser beam. Laser processing is performed by irradiating the third processing point with 5 laser light and irradiating the second processing point 26 after irradiation with the fourth laser light with the sixth laser light. [Selection] Figure 1 (a)

Description

  The present invention relates to a laser processing method for processing a workpiece using laser light, and an inkjet head manufacturing method.

  Processing using laser light such as drilling and cutting is used in various fields such as machinery, electronics, and semiconductors. As a laser processing apparatus that performs these processes, a technique has been proposed in which laser light output from a laser oscillator is branched by a beam splitter, and the branched laser light is irradiated to each processing target to perform laser processing at multiple points. (Patent Document 1).

  In the case of the technique described in Patent Document 1, the intensity ratio of the P-polarized component and the S-polarized component of the laser light incident on the beam splitter is controlled by the angle of the partial reflection mirror. By this control, the energy intensity of each laser beam branched into two by the beam splitter is made equal. By irradiating different processing points to be processed with laser beams having the same energy intensity, similar processing is performed simultaneously.

JP 2003-124552 A

  However, in the case of the technique described in Patent Document 1 described above, the laser beam is branched into laser beams having the same energy intensity, and the same processing is performed by irradiating different processing points. Since processing can be performed at two locations at the same time, the processing time can be shortened, but a laser light source having a laser beam power more than twice that of a normal one is required, which increases the cost of the apparatus.

  In view of such circumstances, the present invention provides a laser processing method and an ink jet head manufacturing method capable of realizing processing with reduced processing time and reduced cost.

The laser processing method of the present invention that solves the above-mentioned problems is a laser processing method for irradiating a laser beam emitted from a pulse laser oscillator to a substrate to make a hole in the substrate, and at least the laser beam Branching into one laser beam and a second laser beam having a pulse energy intensity smaller than that of the first laser beam, irradiating the first laser beam to a first processing point, and at least the laser beam A second branching step of branching into a third laser beam having a pulse energy intensity lower than that of the first laser beam and a fourth laser beam having a pulse energy intensity higher than that of the third laser beam; Irradiating the first processing point after irradiating light with the first laser light, irradiating the second laser processing point with the fourth laser light, the laser light being the fifth laser light, The fourth A third branching step for branching the laser beam to a sixth laser beam having a pulse energy intensity smaller than that of the fifth laser beam, and irradiating the fifth laser beam to a third processing point, Irradiating the second processing point after the irradiation with the laser beam with the fourth laser beam.
The inkjet head manufacturing method of the present invention is characterized in that a groove serving as a path for supplying ink to an ejection hole for ejecting ink droplets is processed by the laser processing method described above.

  According to the present invention, it is possible to realize laser processing with reduced processing time and reduced cost.

The schematic block diagram of the laser processing apparatus used in one Embodiment of this invention. The schematic block diagram of the laser processing apparatus used in one Embodiment of this invention. The schematic block diagram of the laser processing apparatus used in one Embodiment of this invention. The schematic block diagram of the laser processing apparatus used in one Embodiment of this invention. The flowchart of the laser processing process which concerns on the said embodiment. Sectional drawing which shows a part of example of an inkjet head.

  In laser processing, the shape of the processing surface changes with the progress of processing, and the intensity of the laser beam focused on the processing point due to changes in the area of the processing point and the difference in the light propagation state of the laser beam due to the effect of the processing shape. Changes. As a result, the fluence that is the intensity of the laser beam per unit area irradiated to the processing point changes. For example, in the case of hole drilling where the tip of the hole becomes sharp and tapered with the progress of machining, the area of the machining point is large at the initial stage of machining because the machining surface is large, and the machining surface becomes small as the machining progresses, so The area becomes smaller. Further, when the processing progresses and the tip of the hole is sharp, the laser light is collected by the tip of the hole. Thereby, even if the intensity | strength of the laser beam irradiated to a to-be-processed object is constant, the fluence in a process point changes according to progress of a process. Therefore, even if the intensity of the laser beam to be irradiated is set so that the processing efficiency per unit energy is good at the processing point at the beginning of processing, the fluence at the processing point is excessive at the end of processing. Therefore, some of the laser light does not contribute to processing, and energy is wasted. That is, the processing efficiency is deteriorated. Therefore, if the intensity of the laser beam to be irradiated is set so that the machining efficiency per unit energy is good at the end of machining, the fluence at the machining point at the beginning of machining will be too small. It becomes difficult to obtain processing. Therefore, in this embodiment, processing is performed with a laser beam having a higher energy intensity in the initial stage of processing, and processing is performed with a laser beam that is weaker than the energy intensity at the initial stage of processing, so that energy is effectively used. In addition, energy efficient processing is performed.

<Embodiment>
A first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  In FIG. 1, 11 and 12 are substrates, 21 is a laser beam, 22 is a laser beam after passing through a light modulation element, 23 is a laser beam mainly of P wave branched by a polarizer, and 24 is a main beam branched by a polarizer. S-wave laser light. 25 and 26 are processing points. Further, 31 and 32 are condenser lenses, 4 is a pulse laser oscillator, and 51 and 52 are XYZ stages. Reference numeral 6 denotes a polarizer, 7 denotes a light modulation element, 8 denotes a control device, 91 and 92 denote shutter mechanisms, and 20 denotes a mirror.

The substrate 11 and the substrate 12 are workpieces such as a semiconductor material substrate, a glass substrate, and a piezoelectric material substrate. The laser beam 21 is a linearly polarized laser beam emitted from the laser oscillator 4. The processing points 25 and 26 are processing points at which laser light is condensed on the substrates 11 and 12 by the condensing lenses 31 and 32 and processing is performed. As the condensing lenses 31 and 32, an optical system for condensing laser light into a minute spot, an optical system having a scanning mechanism, for example, an optical system combining a galvano scanner and an fθ lens, or the like is used. As the laser oscillator 4, a YAG laser, a CO ₂ laser, an excimer laser, or the like is used. The XYZ stages 51 and 52 freely move the mounted substrate in the XYZ direction. As the polarizer 6, for example, a cube-type polarization beam splitter or a plate-type polarization beam splitter is used. The polarizer 6 mainly includes a P-wave laser beam 23 and a mainly S-wave laser beam 24 according to the polarization direction of the laser beam. Branch. The light modulation element 7 is, for example, an electro-optical element (EOM), and can change the polarization direction of the laser light 21 in accordance with a control signal from the control device 8 and converts it into the laser light 22.

  The P-wave laser beam 23 is the first laser beam in the laser beam 21 and the third laser beam in the laser beam 22, and the S-wave laser beam 24 is the second laser beam and the laser beam 22 in the laser beam 21. In this case, it becomes the fourth laser beam. That is, when the converted laser light 22 passes through the polarizer 6, the second laser light that was S-wave laser light before the conversion in the direction of the first laser light that was P-wave laser light 23 before conversion. Is converted into a P-wave laser beam, and the third laser beam is branched. Then, the first laser light, which was P-wave laser light before conversion, is converted into the S-laser laser light in the direction of the second laser light, which was S-wave laser light 24 before conversion. The laser beam is branched. The light modulation element 7 can respond faster than the oscillation frequency of the laser oscillator 4, and can change the polarization direction of the laser light 21 in accordance with a control signal from the control device 8 for each pulse. The control device 8 controls the laser oscillator 4, the XYZ stages 51 and 52, the light modulation element 7, and the optical elements 91 and 92. The control device 8 also controls the scanning mechanism when the condensing lenses 31 and 32 are optical systems having a scanning mechanism. The shutters 91 and 92 are composed of, for example, an EOM, a polarization beam splitter, and a damper, and can switch between a state in which the laser beam is irradiated to the processing points 25 and 26 and a state in which the damper is irradiated and the processing points 25 and 26 are not irradiated. it can. Further, the optical elements 91 and 92 can respond faster than the oscillation frequency of the laser oscillator 4, and the state of irradiation or non-irradiation of the processing points 25 and 26 is determined for each pulse in accordance with a control signal from the control device 8. Can be changed. As the mirror 20, for example, a dielectric multilayer mirror or a metal vapor deposition mirror is used to reflect the laser light and change the direction. The beam splitter 30 is, for example, a cube type beam splitter, and separates incident laser light into two laser lights having the same intensity.

  Next, an example of a processing step by the laser processing method of the present invention will be described with reference to FIG.

  Laser light 21 is pulse-oscillated at a certain oscillation frequency from the laser oscillator 4. Since the laser 21 is pulse-oscillated at a constant oscillation frequency, there is no variation in excitation time, and the laser light output stability is better than when the oscillation frequency is variable. The direction of polarization of the laser light 21 can be changed by the light modulation element 7 in accordance with a control signal from the control device 8 for each pulse. The ratio of the intensity of the laser beam 23 and that of the laser beam 24 can be switched by switching the ratio of the P-polarized component (P-wave laser beam) and the S-polarized component (S-wave laser beam) of the laser beam 22. For example, here, the ratio of the P-polarized component and the S-polarized component of the laser light 22 is set to 7: 3 or 3: 7 by the light modulation element 7. By this control, the intensity ratio between the laser beam 23 and the laser beam 24 after passing through the polarizer 6 can be set to 7: 3 or 3: 7. The laser light 23 can determine whether the substrate 11 is irradiated or not irradiated by the shutter 91. Further, the laser beam 24 is guided to the shutter 92 via the mirror 20, and it can be determined whether the substrate 12 is irradiated or not. That is, by these mechanisms, it is possible to control whether the substrate 11 is irradiated with the laser beam 23 having a pulse energy intensity of 70% or 30% of the laser beam 22 or not. Similarly, it is possible to control whether the substrate 12 is irradiated with the laser beam 24 having an energy intensity of 70% or 30% of the laser beam 22 or not. Here, the combination of the ratios of the energy intensities applied to the substrate 11 and the substrate 12 is 7: 3, 3 when the intensity of the laser beam 22 before branching is 10 and the non-irradiation state is indicated by 0. : 7, 7: 0, 0: 7, 3: 0, 0: 3, or 0: 0.

  Next, the laser processing step of this embodiment will be described with reference to FIG. Laser light 21 is pulse-oscillated at a certain oscillation frequency from the laser oscillator 4. The laser light 21 can change the ratio of the P-polarized component and the S-polarized component for each pulse by the light modulation element 7 in accordance with a control signal from the control device 8, and at the start of processing, the P-polarized component and the S-polarized component. Is converted into laser light 22 having a ratio of 7: 3. By this control, the laser light after passing through the polarizer 6 can be branched into a laser light 23 having a strength of 70% of the intensity of the laser light 22 and a laser light 24 having a strength of 30% (step: S11).

  Next, the irradiation position of the laser beam 23 is moved to the first hole processing position (first processing position) of the substrate 11. This movement is performed by the XYZ stage 51 or an optical system having a scanning mechanism, for example, a condensing lens 31 constituted by an optical system combining a galvano scanner and an fθ lens, or both. At the same time, the shutter 91 keeps the laser beam 23 from irradiating the substrate 11. Similarly, the shutter 92 keeps the laser beam 24 from irradiating the substrate 12. When the irradiation position of the laser beam 23 has been moved to the first hole processing position (first processing position) of the substrate 11, the laser beam 23 (first laser beam) is transferred to the first hole processing position (first position) of the substrate 11 by the shutter 91. 1 machining position) is irradiated with 100 pulses. At this time, the substrate 12 is not irradiated with the laser beam 24 (second laser beam) and is not processed. In this embodiment, the “laser strength” shown in FIG. 2 is a laser beam having 70% of the intensity of the laser beam 22, and the “laser weak” is 30% of the intensity of the laser beam 22. A case in which the laser beam has the same intensity and the number of pulses L is 100 is described (step: S12).

  Next, the light modulation element 7 converts the P-polarized component and the S-polarized component into a laser beam 22 having a ratio of 3: 7. As a result, the laser beam after passing through the polarizer 6 is divided into a laser beam 23 (third laser beam) having an intensity of 30% of the intensity of the laser beam 22 and a laser beam 24 (fourth laser beam) having an intensity of 70%. (Step: S13).

  Next, the irradiation position of the laser beam 24 (fourth laser beam) is moved to the first hole processing position (second processing position) of the substrate 12. This movement is performed by the XYZ stage 52 or an optical system having a scanning mechanism, for example, a condensing lens 32 constituted by an optical system combining a galvano scanner and an fθ lens, or both. During this movement, the shutter 91 keeps the laser beam 23 (third laser beam) from irradiating the substrate 11. Similarly, the shutter 92 keeps the laser beam 24 (fourth laser beam) from irradiating the substrate 12. The irradiation position of the laser beam 24 (fourth laser beam) is moved to the first hole processing position (second processing position) of the substrate 12. When the movement is completed, the shutter 91 irradiates the laser beam 23 (third laser beam) with 100 pulses to the first hole machining position (first machining position) of the substrate 11 after the irradiation with the first laser beam. Go and drill holes. At the same time, the laser beam 24 (fourth laser beam) is irradiated to the first hole processing position (second processing position) of the substrate 12 by 100 pulses by the shutter 92 (step: S14).

  Next, the light modulation element 7 converts the P-polarized component and the S-polarized component into a laser beam 22 having a ratio of 7: 3. As a result, the laser light after passing through the polarizer 6 is divided into a laser beam 23 (fifth laser beam) having 70% of the intensity of the laser beam 22 and a laser beam 24 (sixth laser) having an intensity of 30%. (Step: S15).

  Next, the irradiation position of the laser beam 23 (fifth laser beam) is moved to the second hole processing position (third processing position) of the substrate 11. This movement is performed by an X-Y-Z stage 51 or an optical system having a scanning mechanism, for example, a condensing lens 31 constituted by an optical system combining a galvano scanner and an fθ lens, or both. During this movement, the shutter 91 keeps the laser beam 23 (fifth laser beam) from irradiating the substrate 11. Similarly, the shutter 92 keeps the laser beam 24 (sixth laser beam) from irradiating the substrate 12. The irradiation position of the laser beam 23 (fifth laser beam) is moved to the second hole processing position (third processing position) of the substrate 11. When the movement is completed, the laser beam 23 (fifth laser beam) is irradiated to the second hole processing position (third processing position) of the substrate 11 by 100 pulses by the shutter 91 and the shutter 92. At the same time, the laser beam 24 (sixth laser beam) is irradiated with 100 pulses at the first hole processing position (second processing position) of the substrate 12 after the fourth laser beam irradiation (step). : S16).

  Next, the light modulation element 7 converts the P-polarized component and the S-polarized component into a laser beam 22 having a ratio of 3: 7. Thus, the laser light after passing through the polarizer 6 is divided into a laser beam 23 (seventh laser beam) having an intensity of 30% of the intensity of the laser beam 22 and a laser beam 24 (eighth laser) having an intensity of 70%. (Step: S17).

  Next, the irradiation position of the laser beam 24 (eighth laser beam) is moved to the second hole processing position (fourth processing position) of the substrate 12. This movement is performed by the XYZ stage 52 or an optical system having a scanning mechanism, for example, a condensing lens 32 constituted by an optical system combining a galvano scanner and an fθ lens, or both. During this movement, the shutter 91 keeps the laser beam 23 (seventh laser beam) from irradiating the substrate 11. Similarly, the shutter 92 keeps the laser beam 24 (eighth laser beam) from irradiating the substrate 12. The irradiation position of the laser beam 24 (eighth laser beam) is moved to the second hole processing position (fourth processing position) of the substrate 12. When the movement is completed, 100 pulses of laser light 23 (seventh laser light) are emitted from the shutter 91 and the shutter 92 to the second hole machining position (third machining position) of the substrate 11 after being irradiated with the fifth laser light. Irradiate. At the same time, the laser beam 24 (eighth laser beam) is processed by irradiating 100 pulses on the second hole processing position (fourth processing position) of the substrate 12 (step: S18).

  The above steps S15 to S18 shown in FIG. 2 are repeated until a desired number of holes are processed in the substrate 11. Here, as an example, a case where the desired number of holes to be processed in the substrate 11 and the substrate 12 is 1000 will be described. The processes of S15 to S18 are repeated, and in the S18th process of the 1000th time, the laser beam 23, which is laser weak, is irradiated to the 1000th hole processing position of the substrate 11 by 100 pulses by the shutter 91 and the shutter 92. At the same time, processing is performed by irradiating the laser beam 24 having high laser intensity with 100 pulses to the 1000th hole processing position of the substrate 12. Thereby, the processing of 1000 holes in the substrate 11 is completed (step: S19).

  Next, the light modulation element 7 converts the P-polarized component and the S-polarized component into a laser beam 22 having a ratio of 7: 3. As a result, the laser beam after passing through the polarizer 6 can be branched into a laser beam 23 having an intensity of 70% of the intensity of the laser beam 22 and a laser beam 24 having an intensity of 30% (step: S20). ).

  Next, processing is performed by irradiating the laser beam 24 with the shutter 92 to the 1000th hole processing position of the substrate 12 by 100 pulses. At this time, the substrate 91 is not irradiated with the laser beam 23 by the shutter 91. Thereby, the processing of 1000 holes on the substrate 12 is completed, and all processing is completed (steps: S21, S22).

  In the case of this embodiment, the laser beam is branched into at least two laser beams having different pulse energies, and the processed laser beam is irradiated with the second and subsequent laser beams by irradiating the branched first laser beam. Processing with good energy utilization efficiency can be realized.

  In this embodiment, the laser beam 22 is split into 7: 3 and 3: 7 laser beams. However, the laser beam 22 is not limited to this branching ratio, and it is 6: 4, 4: 6, 5.5: 4.5, and 4 .5: 5.5, etc., and can be implemented with a free branching ratio according to the shape to be processed. In this embodiment, the total number of pulses irradiated for processing is 100 pulses + 100 pulses and 200 pulses. However, for example, 150 pulses + 150 pulses, 300 pulses, and 80 pulses + 80 pulses, 160 pulses can be implemented with any number of pulses according to the shape to be processed.

  In this embodiment, an XYZ stage is provided for each substrate. However, if the condensing lens 91 and the condensing lens 92 have a scanning mechanism, 1 as shown in FIG. The present invention can also be implemented in a form in which two substrates are mounted on one XYZ stage. In addition, as shown in FIG. 1C, the present invention can also be implemented in a form in which one substrate is mounted on one XYZ stage.

  In the present embodiment, the case where there are two machining points has been described. However, as shown in FIG. 1D, the laser beam is first branched into two by the beam splitter 30, and then the above-described embodiment is performed. It is also possible to adopt and implement the configuration of the form. It is also possible to branch into a plurality of laser beams of three or more first, and then employ the configuration of the present embodiment described above, and carry out with more processing points.

  Examples of the substrate manufactured by the laser processing apparatus and the laser processing method described in the above embodiment include an inkjet head substrate, another semiconductor material substrate, a glass substrate, and a circuit substrate. Further, the processing is not limited to drilling processing such as a leading hole, and processing such as groove shape and cutting can also be performed. Further, the specific application field is not limited to the lead hole processing of the ink jet head, and examples thereof include drilling a circuit substrate and scribing a solar cell substrate.

<Example>
Next, as an example, a substrate manufacturing method for manufacturing a substrate using the laser processing method described in the above embodiment will be described. In this embodiment, the substrate to be manufactured is an inkjet head substrate.

  FIG. 3 is a cross-sectional view of the head portion of the ink jet printer.

  In FIG. 3, 130 is a semiconductor substrate (inkjet head substrate), and 131 is a vertical groove serving as an ink path. Also, 132 is a heater, 133 is a liquid chamber, 134 is an orifice plate, 135 is an ejection hole, 136 is an ink tank, 137 is indicated by a broken line arrow, 137 is an ink path, and 138 is a minute ink droplet. A heater 132 for discharging ink, a liquid chamber 133, and an orifice plate 134 are formed on the lower surface of the semiconductor substrate 130 in which the groove 131 is formed. An ink tank 136 that stores ink is attached to the upper surface of the semiconductor substrate 130. The ink reaches the heater 132 from the ink tank 136 through the groove 131 and the liquid chamber 133. Bubbles formed by instantaneous heating / cooling of the heater 132 push up the ink and are ejected as fine ink droplets 138 from the ejection holes 135 formed through the orifice plate 134.

  In the present embodiment, a plurality of leading holes are formed in a portion that becomes the groove 131 as a path for supplying ink to the ejection holes 135 for ejecting the ink droplets 138 in this way by laser processing as described in the above embodiments. Form. That is, the semiconductor substrate before forming the groove 131 as a workpiece is placed on the stage, and the leading hole is formed by performing the laser processing as described above. This leading hole shortens the time required for anisotropic etching and makes the width of the ink supply port smaller by allowing an etchant to enter the leading hole during anisotropic etching in the post-process of laser processing. Is to do. Then, after the lead hole processing by the laser, the final groove shape is formed by anisotropic etching in an alkaline etching solution for about 15 minutes, for example.

  In addition, the substrate of the inkjet head is manufactured by processing a crystal surface (100) silicon material (workpiece), for example. A mechanism for discharging ink, an etching process after laser processing, and the like are formed on the workpiece, such as a heater, electric wiring, an etching stop layer having etching resistance, and an etching protective film. Moreover, the thickness of a to-be-processed object is about 725 micrometers, for example.

  Such a workpiece is irradiated with laser light until the desired shape of the leading hole is formed. This lead hole has a diameter of 5 to 100 μm in order to reduce the time required for anisotropic etching and reduce the width of the ink supply port by allowing an etchant to enter during anisotropic etching in a later step. It is preferable to do. The depth is preferably 600 to 710 μm when a workpiece having a thickness of 725 μm is used.

11 Substrate 12 Substrate 21 Laser beam 22 Laser beam 23 Laser beam 24 Laser beam 25 Processing point 26 Processing point 31 Condensing lens 32 Condensing lens 4 Laser oscillator 51 XYZ stage 52 XYZ stage 6 Polarizer 7 Light modulator 8 Controller 91 Shutter 92 Shutter 20 Mirror 30 Beam splitter 130 Semiconductor substrate 131 Groove 132 Heater 133 Liquid chamber 134 Orifice plate 135 Discharge hole 136 Ink tank 137 Ink path 138 Ink droplet

Claims (8)

A laser processing method for irradiating a substrate with a laser beam emitted from a pulsed laser oscillator to form a hole in the substrate, wherein the laser beam is pulsed at least more than the first laser beam and the first laser beam. Branching to a second laser beam having a low energy intensity;
Irradiating the first processing position with the first laser beam;
A second branching step of branching the laser light into at least a third laser light having a pulse energy intensity lower than that of the first laser light and a fourth laser light having a pulse energy intensity higher than that of the third laser light; ,
Irradiating the third laser beam to the first processing position after irradiation with the first laser beam and irradiating the fourth laser beam to a second processing position;
A third branching step of branching the laser light into a fifth laser light and a sixth laser light having a pulse energy intensity smaller than that of the fourth laser light and the fifth laser light;
Irradiating the third processing position with the fifth laser beam, and irradiating the second processing position after the irradiation with the fourth laser beam with the sixth laser beam;
A laser processing method comprising:   The laser beam includes a P-wave laser beam and an S-wave laser beam, and the P-wave laser beam and the S-wave laser beam have different pulse energy intensity ratios. Item 2. A laser processing method according to Item 1.   3. The step of branching into the first laser beam and the second laser beam includes branching the laser beam into a P-wave laser beam and an S-wave laser beam by a polarization beam splitter. The laser processing method as described.   The step of branching into the third laser beam and the fourth laser beam includes changing the direction of the polarization direction of the laser beam in the step of branching into the first laser beam and the second laser beam by an optical modulation element, and 4. The laser processing method according to claim 3, wherein the replaced laser beam is branched by a polarization beam splitter.   The step of branching to the fifth laser beam and the sixth laser beam is further performed by using the light modulation element to change the direction of the polarization direction of the interchanged laser beam in the step of branching to the third laser beam and the fourth laser beam. 5. The laser processing method according to claim 4, wherein the laser beam is further split by the polarization beam splitter.   The laser processing method according to claim 1, wherein the first laser beam, the fourth laser beam, and the fifth laser beam have equal pulse energy intensity.   The laser processing method according to claim 1, wherein the second laser light, the third laser light, and the sixth laser light have equal pulse energy intensity.   A method for manufacturing an ink jet head, wherein a groove serving as a path for supplying ink to a discharge hole for discharging an ink droplet is processed by the laser processing method according to claim 1.

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