Laser processing system and laser processing method

Abstract

To provide a laser processing system and a laser processing method.SOLUTION: A laser processing system, which forms a plurality of dents on a plurality of processed regions separated from each other in a first direction on a surface of a work-piece by irradiating the regions with pulse laser beams, comprises: a gas laser device that emits a pulse laser beam; a moving part that can move an irradiation region on the surface for a pulse laser beam, in the first direction; and a first galvano-scanner that can change a beam path of a pulse laser beam to move the irradiation region, in the first direction. The moving part moves the irradiation region so that the region overlaps with a portion of an irradiation region irradiated with pulse laser beams lastly. The first galvano-scanner moves the irradiation region so that the region is positioned in a processed region which is different from a processed region irradiated with pulse laser beams lastly.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to a laser processing system and a laser processing method.

Background Art

[0002] In recent years, in semiconductor exposure apparatuses, as semiconductor integrated circuits have been miniaturized and highly integrated, an improvement in resolution has been demanded. For this reason, the wavelength of light emitted from an exposure light source has been shortened. For example, as a gas laser apparatus for exposure, a KrF excimer laser apparatus that outputs laser light having a wavelength of about 246.0 nm and an ArF excimer laser apparatus that outputs laser light having a wavelength of about 193.4 nm are used.

[0003] The spectral linewidth of the spontaneous emission light of a KrF excimer laser apparatus and an ArF excimer laser apparatus is as wide as 350 pm to 400 pm. Therefore, when a projection lens is configured with a material that transmits ultraviolet light such as KrF and ArF laser light, chromatic aberration may occur. As a result, the resolution may decrease. Therefore, it is necessary to narrow the spectral linewidth of the laser light output from the gas laser apparatus to such an extent that chromatic aberration can be ignored. For this reason, a narrowbanding module (Line Narrowing Module: LNM) including a narrowbanding element (etalon, grating, etc.) may be provided in the laser resonator of the gas laser apparatus in order to narrow the spectral linewidth. Hereinafter, a gas laser apparatus in which the spectral linewidth is narrowed is referred to as a narrowbanding gas laser apparatus.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] A laser processing system according to one aspect of the present disclosure is a laser processing system that irradiates a plurality of processing regions spaced apart from each other in a first direction on the surface of a workpiece to form a plurality of recesses, including a gas laser device that emits pulsed laser light, a moving unit that can move an irradiation region on the surface of the pulsed laser light in the first direction, and a first galvanometer scanner that can change the optical path of the pulsed laser light to move the irradiation region in the first direction. The moving unit moves the irradiation region so as to overlap a part of the irradiation region of the immediately preceding pulsed laser light, and the first galvanometer scanner may move the irradiation region so as to be located in a processing region different from the processing region irradiated with the immediately preceding pulsed laser light.

[0006] A laser processing method according to one aspect of the present disclosure is a laser processing method that irradiates a plurality of processing regions spaced apart from each other in a first direction on the surface of a workpiece to form a plurality of recesses, including a first step of moving an irradiation region on the surface of the pulsed laser light by a moving unit that can move the irradiation region in the first direction so as to overlap a part of the irradiation region of the immediately preceding pulsed laser light within the processing region irradiated with the immediately preceding pulsed laser light, and a second step of moving the irradiation region by a first galvanometer scanner that can change the optical path of the pulsed laser light to move the irradiation region in the first direction so as to be located in a processing region different from the processing region irradiated with the immediately preceding pulsed laser light.

Brief Description of the Drawings

[0007] Some embodiments of the present disclosure will be described below by way of example only with reference to the accompanying drawings.

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[0008] 1. Description of the Laser Processing System and Laser Processing Method of the Comparative Example 1.1 Configuration 1.2 Operation 1.3 Problems 2. Description of the Laser Processing System and Laser Processing Method of Embodiment 1 2.1 Configuration 2.2 Operation 2.3 Function and Effect 3. Description of the Laser Processing System and Laser Processing Method of Embodiment 2 3.1 Configuration 3.2 Operation 3.3 Function and Effect 4. Description of the Laser Processing System and Laser Processing Method of Embodiment 3 4.1 Configuration 4.2 Operation 4.3 Function and Effect Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show some examples of the present disclosure and do not limit the content of the present disclosure. Also, not all of the configurations and operations described in each embodiment are essential as the configurations and operations of the present disclosure. The same reference numerals are assigned to the same components, and redundant descriptions are omitted.

[0009] 1. Description of the Laser Processing System and Laser Processing Method of the Comparative Example 1.1 Configuration The laser processing system and laser processing method of the comparative example will be described. Note that the comparative example of the present disclosure is a form recognized by the applicant as being known only to the applicant and is not a publicly known example recognized by the applicant.

[0010] FIG. 1 is a schematic diagram showing an overall schematic configuration example of the laser processing system 10 of this example. The laser processing system 10 of this example mainly includes an argon fluoride (ArF) excimer laser device 100, a laser processing device 300, and an optical path tube PO connecting the argon fluoride laser device 100 and the laser processing device 300. Hereinafter, the direction parallel to the optical axis direction of the laser beam incident on the workpiece 20 will be described as the Z direction, the first direction orthogonal to the Z direction as the X direction, and the second direction orthogonal to the X direction and the Z direction as the Y direction. The Z direction is also the height direction of the workpiece 20.

[0011] The argon fluoride laser device 100 of this example is an ArF excimer laser device that uses a mixed gas containing argon (Ar), fluorine (F2), and neon (Ne). The argon fluoride laser device 100 outputs a laser beam having a central wavelength of about 193.4 nm. Note that the argon fluoride laser device 100 may be a gas laser device other than an ArF excimer laser device. For example, it may be a KrF excimer laser device that uses a mixed gas containing krypton (Kr), F2, and Ne. In this case, the argon fluoride laser device 100 emits a laser beam having a central wavelength of about 246.0 nm. The mixed gas containing Ar, F2, and Ne as the laser medium or the mixed gas containing Kr, F2, and Ne as the laser medium may be called a laser gas.

[0012] The gas laser device 100 mainly includes a housing 110, a laser oscillator 130 disposed in the internal space of the housing 110, a monitor module 150, a shutter 170, and a laser processor 190.

[0013] The laser oscillator 130 includes a laser chamber 131, a charger 141, a pulse power module 143, a rear mirror 145, and an output coupling mirror 147. In FIG. 1, the internal configuration of the laser chamber 131 is shown as viewed from a direction substantially perpendicular to the traveling direction of the laser light.

[0014] The laser chamber 131 includes an internal space where light is generated by excitation of the laser medium in the laser gas. The light travels to windows 139a and 139b, which will be described later. The laser gas is supplied from a laser gas supply source (not shown) to the internal space of the laser chamber 131 through a pipe (not shown). Further, the laser gas in the laser chamber 131 is subjected to a process such as removing F2 gas by a halogen filter, and is exhausted to the housing 110 through a pipe (not shown) by an exhaust pump (not shown).

[0015] In the internal space of the laser chamber 131, a pair of electrodes 133a and 133b face each other, and their longitudinal directions are arranged along the traveling direction of the light. The electrodes 133a and 133b are discharge electrodes for exciting the laser medium by glow discharge. In this example, the electrode 133a is a cathode and the electrode 133b is an anode.

[0016] The electrode 133a is supported by an electrical insulating portion 135. The electrical insulating portion 135 closes an opening formed in the laser chamber 131. A conductive portion (not shown) is embedded in the electrical insulating portion 135, and the conductive portion applies a high voltage supplied from the pulse power module 143 to the electrode 133a. The electrode 133b is supported by a return plate 137, and the return plate 137 is connected to the inner surface of the laser chamber 131 by wiring (not shown).

[0017] The charger 141 is a DC power supply device that charges a charging capacitor (not shown) in the pulse power module 143 to a predetermined voltage. The pulse power module 143 includes a switch 143a controlled by the laser processor 190. When the switch 143a changes from OFF to ON, the pulse power module 143 generates a pulsed high voltage from the electrical energy held in the charger 141 and applies this high voltage between the electrode 133a and the electrode 133b.

[0018] When a high voltage is applied between the electrode 133a and the electrode 133b, a discharge occurs between the electrode 133a and the electrode 133b. The energy of this discharge excites the laser medium in the laser chamber 131, and the excited laser medium emits light when transitioning to the ground state.

[0019] Windows 139a and 139b are provided in the laser chamber 131. The window 139a is located on one end side in the traveling direction of the laser light in the laser chamber 131, the window 139b is located on the other end side in the traveling direction, and the windows 139a and 139b sandwich the space between the electrode 133a and the electrode 133b. The windows 139a and 139b are inclined at a Brewster angle with respect to the traveling direction of the laser light so that the reflection of the P-polarized laser light is suppressed. The laser light oscillating as described later exits the laser chamber 131 through the windows 139a and 139b. Since the pulsed high voltage is applied between the electrode 133a and the electrode 133b by the pulse power module 143 as described above, this laser light is pulsed laser light.

[0020] The rear mirror 145 is disposed in the internal space of a housing 145a connected to one end side of the laser chamber 131, and reflects the laser light emitted from the window 139a and returns it to the laser chamber 131. The output coupling mirror 147 is disposed in the internal space of an optical path tube 147a connected to the other end side of the laser chamber 131, transmits a part of the laser light emitted from the window 139b, and reflects the other part of the laser light and returns it to the internal space of the laser chamber 131. In this way, the rear mirror 145 and the output coupling mirror 147 constitute a Fabry - Perot type laser resonator, and the laser chamber 131 is disposed on the optical path of the laser resonator.

[0021] The monitor module 150 is disposed on the optical path of the laser light emitted from the output coupling mirror 147. The monitor module 150 includes, for example, a housing 151, a beam splitter 153 disposed in the internal space of the housing 151, and an optical sensor 155. An opening is formed in the housing 151, and through this opening, the internal space of the housing 151 communicates with the internal space of the optical path tube 147a.

[0022] The beam splitter 153 transmits a part of the laser light emitted from the output coupling mirror 147 toward the shutter 170, and reflects the other part of the laser light toward the light receiving surface of the optical sensor 155. The optical sensor 155 measures the energy E of the laser light incident on the light receiving surface. The optical sensor 155 outputs a signal indicating the measured energy E to the laser processor 190.

[0023] The laser processor 190 of the present disclosure is a processing device including a storage device 190a in which a control program is stored and a CPU (Central Processing Unit) 190b that executes the control program. The laser processor 190 is specially configured or programmed to execute various processes included in the present disclosure. Further, the laser processor 190 controls the entire gas laser device 100.

[0024] The laser processor 190 transmits and receives various signals to and from the laser processing processor 310 of the laser processing apparatus 300. For example, the laser processor 190 receives from the laser processing processor 310 a signal indicating a light emission trigger Tr and a target energy Et, which will be described later. The laser processor 190 controls the charging voltage of the charger 141 based on the energy E received from the optical sensor 155 and the target energy Et received from the laser processing processor 310. By controlling this charging voltage, the energy of the laser light is controlled. Further, the laser processor 190 transmits an ON or OFF command signal for the switch 143a to the pulse power module 143. Also, the laser processor 190 is electrically connected to the shutter 170 and controls the opening and closing of the shutter 170.

[0025] The laser processor 190 closes the shutter 170 until the difference ΔE between the energy E received from the monitor module 150 and the target energy Et received from the laser processing processor 310 is within the allowable range. When the difference ΔE is within the allowable range, the laser processor 190 transmits a reception preparation completion signal indicating that the reception preparation for the light emission trigger Tr has been completed to the laser processing processor 310. When the laser processing processor 310 receives the reception preparation completion signal, it transmits a signal indicating the light emission trigger Tr to the laser processor 190, and when the laser processor 190 receives the signal indicating the light emission trigger Tr, it opens the shutter 170. The light emission trigger Tr is defined by a predetermined repetition frequency f and a predetermined number of pulses P of the laser light, and is a timing signal for the laser processing processor 310 to cause the laser oscillator 130 to oscillate laser light, and is an external trigger. The repetition frequency f of the laser light is, for example, 1 kHz or more and 10 kHz or less.

[0026] The shutter 170 is disposed in the optical path of the laser beam that has passed through the beam splitter 153 of the monitor module 150 and passed through the opening formed on the side of the housing 151 opposite to the side to which the optical path tube 147a is connected. Further, the shutter 170 is disposed in the internal space of the optical path tube 171, and the optical path tube 171 is connected to the housing 151 so as to surround the opening and communicates with the housing 151. Further, the optical path tube 171 communicates with the laser processing apparatus 300 through the opening of the housing 110 and the optical path tube PO.

[0027] The internal spaces of the optical path tube 171 and the optical path tube 147a, and the internal spaces of the housing 151 and the housing 145a are filled with a purge gas. The purge gas includes an inert gas such as nitrogen (N2). The purge gas is supplied from a purge gas supply source (not shown) through a pipe (not shown) to the internal spaces of the optical path tube 171 and the optical path tube 147a, and the internal spaces of the housing 151 and the housing 145a.

[0028] The laser processing apparatus 300 mainly includes a laser processing processor 310, an optical system 330, a stage 350, a housing 355, and a frame 357. The optical system 330 and the stage 350 are disposed in the internal space of the housing 355. The housing 355 is fixed to the frame 357. An optical path tube PO is connected to the housing 355, and the internal space of the housing 355 communicates with the internal space of the optical path tube PO through the opening formed in the housing 355, and the laser beam that has passed through the shutter 170 enters the housing 355.

[0029] The laser processing processor 310 is a processing device including a storage device 310a in which a control program is stored and a CPU 310b that executes the control program. The laser processing processor 310 is specially configured or programmed to execute various processes included in the present disclosure. The laser processing processor 310 controls the entire laser processing apparatus 300.

[0030] The optical system 330 includes high-reflection mirrors 331a, 331b, 331c, an attenuator 332, a fly-eye lens 333, a condenser lens 334, a mask 335, and a projection optical system 336. Each component of the optical system 330 is fixed to a holder (not shown) and is arranged at a predetermined position within the housing 355.

[0031] The high-reflection mirrors 331a, 331b, 331c are formed, for example, by coating a reflective film that highly reflects laser light on the surface of a transparent substrate made of synthetic quartz or calcium fluoride. The high-reflection mirror 331a reflects the laser light incident from the gas laser device 100 toward the attenuator 332. The high-reflection mirror 331b reflects the laser light from the attenuator 332 toward the high-reflection mirror 331c. The high-reflection mirror 331c reflects the laser light from the high-reflection mirror 331b toward the fly-eye lens 333.

[0032] The attenuator 332 is arranged on the optical path between the high-reflection mirror 331a and the high-reflection mirror 331b. The attenuator 332 includes, for example, rotation stages 332a, 332b and partial reflection mirrors 332c, 332d fixed to the rotation stages 332a, 332b. Each rotation stage 332a, 332b is electrically connected to the laser processing processor 310 and rotates around the Y-axis by a control signal from the laser processing processor 310. When the rotation stages 332a, 332b rotate respectively, the partial reflection mirrors 332c, 332d also rotate respectively. The partial reflection mirrors 332c, 332d are optical elements whose transmittance changes depending on the incident angle of the laser light Lb to the partial reflection mirrors 332c, 332d. The rotation angle of the partial reflection mirrors 332c, 332d around the Y-axis is adjusted by the rotation of the rotation stages 332a, 332b so that the incident angles of the laser light are the same and the transmittance of the partial reflection mirrors 332c, 332d becomes the desired transmittance. Thereby, the laser light from the high-reflection mirror 331a is attenuated to the desired energy and passes through the attenuator 332.

[0033] The fly-eye lens 333 is a lens in which a plurality of lenses are arranged in parallel, for example, in a honeycomb shape, and is also called an integrator lens. The fly-eye lens 333 is arranged such that the focal plane on the exit side of the fly-eye lens 333 coincides with the focal plane on the incident surface side of the condenser lens 334, and emits light so that the energy density of the laser light incident on the condenser lens 334 becomes uniform.

[0034] The condenser lens 334 is a lens that condenses the laser light emitted from the fly-eye lens 333, and is arranged such that the focal plane on the exit side of the condenser lens 334 is on the mask 335.

[0035] The mask 335 is, for example, a plate-like member in which a transmission hole through which a part of the laser light passes is formed, and another part of the laser light is blocked. In this example, the transmission hole is formed of a rectangular hole, and when the laser light passes through the transmission hole, the outer shape of the laser light becomes a rectangular shape elongated in the Y direction.

[0036] The projection optical system 336 includes, for example, a collimator lens 336a and a condenser lens 336b. The collimator lens 336a emits the laser light from the mask 335 as parallel light. The condenser lens 336b condenses the laser light from the collimator lens 336a onto the surface of the workpiece 20.

[0037] The stage 350 is arranged on the bottom surface of the housing 355 and includes a table 351. Further, the stage 350 can move the table 351 in the X direction, Y direction, and Z direction by a control signal from the laser processing processor 310, and the position of the table 351 can be adjusted by this movement.

[0038] Table 351 supports the workpiece 20. The main surface of table 351 is generally orthogonal to the Z-axis and generally along the XY plane. Therefore, the front and back surfaces of the workpiece 20 are generally orthogonal to the Z-axis and are generally located along the XY plane. With the above configuration, the stage 350 can move the workpiece 20 via the table 351 so that a plurality of laser beams emitted from the optical system 330 irradiate a desired position of the workpiece 20, and adjust the position of the workpiece 20. That is, the stage 350 is a moving part that can move the irradiation area of the laser beam on the surface of the workpiece 20 in the X direction and Y direction perpendicular to the irradiation direction of the laser beam.

[0039] The workpiece 20 is an object to be laser processed by irradiation with a laser beam. As the workpiece 20, for example, a light-transmissive plate-like member serving as an optical waveguide substrate can be cited. Examples of the material constituting this plate-like member include polyimide resin and polynorbornene resin.

[0040] An inert gas constantly flows in the internal space of the housing 355 during the operation of the laser processing system 10. This inert gas is, for example, nitrogen gas. The housing 355 is provided with a suction port (not shown) for sucking the inert gas into the housing 355 and a discharge port (not shown) for discharging the inert gas from the housing 355 to the outside. An intake pipe and a discharge pipe (not shown) are connected to the suction port and the discharge port. A gas supply source (not shown) for supplying the inert gas is connected to the suction port through a pipe. The inert gas supplied from the suction port also flows into the optical path tube PO communicating with the housing 355.

[0041] 1.2 Operation Next, the operation of the laser processing system 10 of the comparative example and the laser processing method will be described.

[0042] In the gas laser device 100, before the gas laser device 100 emits laser light, the internal spaces of the optical path tubes 147a, 171, and PO, and the internal spaces of the housings 145a and 151 are filled with purge gas from a purge gas supply source (not shown). Further, laser gas is supplied from a laser gas supply source (not shown) to the internal space of the laser chamber 131. In the laser processing device 300, an inert gas such as nitrogen gas flows through the internal space of the housing 355.

[0043] In the laser processing device 300, the workpiece 20 is supported on the table 351. The laser processing processor 310 sets the coordinates X, Y, and Z of the initial irradiation position at which laser light is irradiated to form the processed part on the stage 350. Thereby, the stage 350 moves the table 351 together with the workpiece 20 to the set initial irradiation position. Note that the irradiation position is the position of the center of the irradiation region where the laser light is irradiated.

[0044] After the table 351 has moved, the laser processing processor 310 controls the transmittance of the attenuator 332 of the optical system 330 and the gas laser device 100 so that the laser light irradiated on the workpiece 20 has a desired fluence F required for laser processing. The fluence F is defined as a value obtained by dividing the energy of the laser light by the cross-sectional area of the laser light perpendicular to the optical axis of the laser light.

[0045] The laser processor 190 closes the shutter 170 and drives the charger 141. Also, the laser processor 190 turns on the switch 143a of the pulse power module 143. Thereby, the pulse power module 143 applies a pulsed high voltage between the electrode 133a and the electrode 133b from the electrical energy held in the charger 141. Due to this high voltage, a discharge occurs between the electrode 133a and the electrode 133b, and the laser medium contained in the laser gas between the electrode 133a and the electrode 133b is excited and emits light when returning to the ground state. Due to this light, light resonates between the rear mirror 145 and the output coupling mirror 147, and the light is amplified each time it passes through the discharge space in the internal space of the laser chamber 131, and laser oscillation occurs. And a part of the laser light passes through the output coupling mirror 147 as pulsed laser light and travels to the beam splitter 153.

[0046] A part of the laser light that has traveled to the beam splitter 153 is reflected by the beam splitter 153 and received by the optical sensor 155. The optical sensor 155 measures the energy E of the received laser light and outputs a signal indicating the energy E to the laser processor 190. The laser processor 190 controls the charging voltage so that the difference ΔE between the energy E and the target energy Et is within the allowable range, and after the difference ΔE is within the allowable range, it transmits a reception preparation completion signal indicating that the reception preparation of the emission trigger Tr has been completed to the laser processing processor 310.

[0047] When the laser processing processor 310 receives the reception preparation completion signal, it transmits the emission trigger Tr to the laser processor 190. When the laser processor 190 opens the shutter 170 in synchronization with the reception of the emission trigger Tr, the laser light that has passed through the shutter 170 enters the laser processing apparatus 300. This laser light is, for example, pulsed laser light with a central wavelength of 193.4 nm.

[0048] The laser light incident on the laser processing apparatus 300 is irradiated onto the mask 335 via the high reflection mirror 331a, the attenuator 332, the high reflection mirrors 331b and 331c, the fly-eye lens 333, and the condenser lens 334. At this time, the laser light is Koehler illuminated on the mask 335. On the mask 335, among the laser light, a part of the laser light passes through the through holes and becomes laser light having a rectangular shape elongated in the Y direction, and the other part of the laser light is blocked. The laser light that has passed through the mask 335 is made into parallel light by the collimator lens 336a of the projection optical system 336 and is condensed on the surface of the workpiece 20 by the condenser lens 336b.

[0049] The laser light is irradiated onto the workpiece 20 according to the emission trigger Tr defined by the repetition frequency f and the number of pulses P required for laser processing. In the vicinity of the surface of the workpiece 20, ablation occurs due to the irradiation of the laser light, and defects are generated. As a result, a processed portion is processed on the workpiece 20, and a dent is formed. In this example, a plurality of processed portions spaced apart from each other are processed, and a plurality of dents are formed.

[0050] FIG. 2 is a diagram for explaining the processing order on the surface of the workpiece 20. The processing region 21 shown in FIG. 2 is a region where the laser light is irradiated for processing. A set 26 composed of a plurality of processing regions 21 spaced apart from each other in the X direction is arranged in the Y direction. In this example, the number of sets 26 is two, and an example in which the number of processing regions 21 in the set 26 is two is shown, but the number of sets 26 and the number of processing regions 21 in the set 26 are not limited.

[0051] The outer shape of the processing region 21 in this example is generally rectangular including opposite sides facing each other in the X direction and opposite sides facing each other in the Y direction. The width of the processing region 21 in the Y direction is substantially the same as the width of the irradiation region 22 where the laser light is irradiated in one pulse, and the width of the processing region 21 in the X direction is wider than the width of the irradiation region 22 in the X direction and is approximately twice the width. For this reason, by irradiating the laser light a plurality of times, the entire processing region 21 is irradiated with the laser light. In FIG. 2, in order to distinguish the processing region 21 and the irradiation region 22, the irradiation region 22 is hatched with a plurality of dots.

[0052] FIG. 3 is a diagram showing an example of the irradiation area 22 in the first irradiation with respect to the processing area 21, and FIG. 4 is a cross-sectional view showing the state of the workpiece 20 after the first irradiation with respect to the processing area 21. As shown in FIG. 3, in this example, first, the workpiece 20 is moved by the stage 350 so that the irradiation area 22 extends along one edge of the processing area 21 in the X direction, and the surface of the workpiece 20 is irradiated with laser light. For this reason, the irradiation area 22 is irradiated with laser light, and as shown in FIG. 4, a recess 25 is formed in the workpiece 20.

[0053] FIG. 5 is a diagram showing an example of the irradiation area 22a in the second irradiation with respect to the processing area 21, and FIG. 6 is a cross-sectional view showing the state of the workpiece 20 after the second irradiation with respect to the processing area 21. After the first irradiation with respect to the processing area 21, as shown in FIG. 5, the workpiece 20 is moved to one side in the X direction by the stage 350, and the surface of the workpiece 20 is irradiated with laser light. The irradiation area 22a of the laser light irradiated at this time overlaps a part of the irradiation area 22 of the laser light irradiated immediately before, and the center 23a of the irradiation area 22a is located on the other side in the X direction from the center 23 of the irradiation area 22. This irradiation area 22a is an area where the irradiation area 22a where the irradiation area 22 overlaps moves in the short side direction of the outer shape of the laser light. Also, the direction from the center 23a of the irradiation area 22a toward the center 23 of the irradiation area 22 where the irradiation area 22a overlaps is the X direction, and the width of the processing area 21 in the X direction is twice the width of the laser light in the short side direction. In FIG. 5, in order to distinguish between the irradiation area 22 and the irradiation area 22a, the irradiation area 22 is hatched with a plurality of dots, and the irradiation area 22a is hatched with a plurality of slashes.

[0054] By irradiating the irradiation area 22a with laser light, as shown in FIG. 6, another recess 25 is formed in the workpiece 20. Since the irradiation area 22a overlaps with a part of the irradiation area 22 of the laser light irradiated immediately before, a part of the edge of the irradiation area 22 is located within the irradiation area 22a. Corners are more easily processed by laser light than flat parts. Therefore, the corners along the edge of the irradiation area 22 located within the irradiation area 22a are more easily processed than other parts and have a chamfered shape.

[0055] FIG. 7 is a cross-sectional view showing the state of the workpiece 20 after the entire processing area 21 has been irradiated with laser light. The movement of the irradiation area 22 of the laser light and the irradiation of the laser light are repeated until the irradiation area 22 of the laser light reaches along the other edge of the processing area 21 in the X direction, and the entire processing area 21 is irradiated with the laser light. In this way, by forming a plurality of recesses 25, the recess 30 shown in FIG. 7 is formed. As described above, corners are more easily processed by laser light than flat parts, and the other part in the X direction at the edge of the recess 25 is irradiated with laser light many times. Therefore, the other part in the X direction at the edge of the recess 30 becomes a generally flat inclined surface 31, and the part on one side in the X direction at the edge of the recess 30 becomes stepped. The inclined surface 31 is the surface on which the reflective film serving as the micromirror of the optical waveguide substrate is provided. In this example, the recess 30 is not a through hole penetrating to the back surface of the workpiece 20, but may be a through hole.

[0056] Next, the workpiece 20 is moved by the stage 350 so that the irradiation area 22 is along the one edge of the other processing area 21 in the X direction, and the above-described irradiation of the laser light and the movement of the irradiation area 22 are repeated. In this example, the processing areas 21 irradiated with laser light are changed in the order of the arrows a, b, and c shown in FIG. 2. In this way, a plurality of recesses 30 are formed in the workpiece 20. The direction in which the irradiation area 22 moves in each processing area 21 is the direction from one side to the other side in the X direction. Therefore, the inclined surface 31 in the recess 30 formed for each processing area 21 is inclined toward the surface side of the workpiece 20 from one side to the other side in the X direction.

[0057] 1.3 Problems The moving distance of the irradiation area 22 between different processing areas 21 is longer than the moving distance of the irradiation area 22 within the same processing area 21. Therefore, it takes a long time for the irradiation area 22 to move between the processing areas 21, resulting in a long processing time.

[0058] Therefore, in the following embodiments, a laser processing system 10 and a laser processing method capable of shortening the processing time are exemplified.

[0059] 2. Description of the Laser Processing System and Laser Processing Method of Embodiment 1 The laser processing system 10 and the laser processing method of Embodiment 1 will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted unless otherwise specified.

[0060] 2.1 Configuration FIG. 8 is a schematic diagram showing a schematic configuration example of the laser processing apparatus 300 of the present embodiment. As shown in FIG. 8, in the laser processing apparatus 300 of the present embodiment, the arrangements of the fly-eye lens 333, the condenser lens 334, and the mask 335 are different from those in the laser processing apparatus 300 of the comparative example. Further, the laser processing apparatus 300 of the present embodiment includes a galvanometer scanner 361 as a first galvanometer scanner and a galvanometer scanner 362 as a third galvanometer scanner instead of the high-reflection mirror 331c, and includes an fθ lens 370 instead of the projection optical system 336.

[0061] The fly-eye lens 333, the condenser lens 334, and the mask 335 are arranged on the optical path between the attenuator 332 and the high-reflection mirror 331b.

[0062] The galvanometer scanner 361 includes a drive unit 361a and a mirror 361b attached to the swing axis of the drive unit 361a and swingable around the swing axis. Further, the configuration of the galvanometer scanner 362 is the same as that of the galvanometer scanner 361, and the galvanometer scanner 362 includes a drive unit 362a and a mirror 362b attached to the swing axis of the drive unit 362a and swingable around the swing axis.

[0063] The drive units 361a and 362a are motors or the like, and are electrically connected to the laser processing processor 310. The swing speed and swing angle of the swing axes of the drive units 361a and 362a are controlled by control signals from the laser processing processor 310. The swing axis of the drive unit 361a is orthogonal to the swing axis of the drive unit 362a.

[0064] The mirror 361b reflects the laser light from the high reflection mirror 331b toward the mirror 362b, and the mirror 362b reflects the laser light from the mirror 361b toward the fθ lens 370. The respective orientations of the mirrors 361b and 362b are adjusted by the swing angles of the respective swing axes of the drive units 361a and 362a. The adjustment of the respective orientations of the mirrors 361b and 362b may be synchronized. The speeds of the mirrors 361b and 362b during swinging are adjusted by the swing speeds when the swing axes of the drive units 361a and 362a swing.

[0065] The galvanometer scanner 361 can change the optical path of the laser light along the X direction by the mirror 361b and move the irradiation region 22 of the laser light in the X direction. The galvanometer scanner 362 can change the optical path of the laser light along the Y direction by the mirror 362b and move the irradiation region 22 of the laser light in the Y direction. That is, the galvanometer scanner 361 is a moving part that can move the irradiation region 22 of the laser light in the X direction perpendicular to the irradiation direction of the laser light. Also, the galvanometer scanner 362 is a moving part that can move the irradiation region 22 of the laser light in the Y direction perpendicular to the irradiation direction of the laser light. The minimum moving distance of the irradiation region 22 adjustable by the galvanometer scanner 361 is approximately the same as the minimum moving distance of the irradiation region 22 adjustable by the galvanometer scanner 362. Also, it is preferable that the minimum moving distance in the X direction of the irradiation region 22 adjustable by the stage 350 is shorter than the minimum moving distance of the irradiation region 22 adjustable by the galvanometer scanner 361. Also, it is preferable that the minimum moving distance in the Y direction of the irradiation region 22 adjustable by the stage 350 is shorter than the minimum moving distance of the irradiation region 22 adjustable by the galvanometer scanner 362. Note that the relationship of the lengths of these minimum moving distances is not restricted.

[0066] The fθ lens 370 is fixed to a holder (not shown) on the optical path between the mirror 362b and the workpiece 20, and is disposed at a predetermined position within the housing 355. The optical axis of the fθ lens 370 is along the Z direction. The fθ lens 370 condenses the laser light irradiated from the galvanometer scanner 362 onto the surface of the workpiece 20 along the optical axis of the fθ lens 370.

[0067] 2.2 Operation Next, the operation of the laser processing processor 310 in the present embodiment will be described.

[0068] FIG. 9 is a diagram showing a control flowchart of the laser processing processor 310 of the present embodiment. The control flowchart of the present embodiment includes steps SP11 to SP17, and shows a laser processing method for forming a plurality of recesses 30 in the workpiece 20.

[0069] In the start state shown in FIG. 9, the laser processing processor 310 has received a reception ready signal from the laser processor 190, but has not transmitted the emission trigger Tr to the laser processor 190. Therefore, although the laser light is emitted from the laser oscillator 130, the shutter 170 is closed, so the laser light does not enter the laser processing apparatus 300 from the gas laser apparatus 100. Also, in the start state, the workpiece 20 is already supported by the table 351.

[0070] (Step SP11) This step is a preparation step before the laser processing apparatus 300 starts actual operation. In this step, the laser processing processor 310 reads parameters from the storage device 310a. The parameters of the present embodiment include the number nmax of processing regions 21, the maximum number mmax of times of irradiating the laser light on each processing region 21, the number n, and the coordinates of the processing region 21.

[0071] The machining areas 21 are numbered from 1 to nmax. The number n is the number of the machining area 21, and the initial value of n is 1. In the present embodiment, the numbers increase in the order of the arrow a, the arrow b, and the arrow c shown in FIG. 2. The coordinates of the machining area 21 are the XY coordinates of the center 23 of the irradiation area 22 along one edge of the machining area 21 in the X direction as shown in FIG. 3.

[0072] (Step SP12) This step is to move the table 351 of the stage 350. In this step, the laser processing processor 310 controls the stage 350 so that the table 351 moves at a constant speed from the other side to one side in the X direction. The control continues until step SP16. When starting the control, the laser processing processor 310 advances the control flow to step SP13.

[0073] (Step SP13) This step is to move the irradiation position of the laser beam. In this step, the laser processing processor 310 controls the galvanoscanners 361, 362 so that the coordinates of the irradiation position become the coordinates of the machining area 21 with the number n. The coordinates of the irradiation position are the XY coordinates of the center 23 of the irradiation area 22 when irradiating the laser beam. When the movement of the irradiation position is performed, the laser processing processor 310 advances the control flow to step SP14.

[0074] (Step SP14) This step is to irradiate the workpiece 20 with laser light at a predetermined time interval. In this step, the laser processing processor 310 sends a light emission trigger Tr to the laser processor 190 to cause the shutter 170 of the laser processor 190 to open. As a result, the laser light enters the laser processing apparatus 300 from the gas laser apparatus 100. The incident laser light travels in the order of the high reflection mirror 331a, the attenuator 332, the condenser lens 334, the mask 335, the high reflection mirror 331b, the mirror 361b, the mirror 362b, and the fθ lens 370, and is irradiated onto the workpiece 20. The workpiece 20 is processed by the irradiation of the laser light. During this step, since the table 351 moves at a constant speed from the other side to one side in the X direction, the workpiece 20 also moves at a constant speed from the other side to one side in the X direction. For this reason, the irradiation area 22 moves toward the other side in the X direction as time passes. In the present embodiment, the time interval for irradiating the laser light is adjusted such that the irradiation area 22 overlaps a part of the irradiation area 22 irradiated with the immediately preceding laser light, and the irradiation area 22 at the mmax-th irradiation is along the edge on the other side in the X direction of the processing area 21. For this reason, the stage 350 moves the irradiation area 22 so as to overlap a part of the irradiation area 22 of the immediately preceding laser light. Further, this movement is a first step of moving the irradiation area 22 by the stage 350 capable of moving the irradiation area 22 in the X direction so as to overlap a part of the irradiation area 22 of the immediately preceding laser light, and the first step and the irradiation of the laser light are repeated. By irradiating the laser light mmax times, the entire processing area 21 is irradiated with the laser light, and a recess 30 is formed in the processing area 21. When the laser processing processor 310 performs the irradiation of the laser light at the mmax-th time, the control flow proceeds to step SP15.

[0075] (Step SP15) This step is to increase the number n by 1. In this step, the laser processing processor 310 rewrites the number n to n + 1 and advances the control flow to step SP16.

[0076] (Step SP16) This step is to vary the next step according to the number n. In this step, when the number n is less than or equal to nmax, the laser processing processor 310 returns the control flow to step SP13, and when the number n is greater than nmax, the control flow proceeds to step SP17. Therefore, when there is a processing area 21 not irradiated with laser light, the galvanoscanners 361 and 362 move the irradiation area 22 so as to be located within a processing area 21 different from the processing area 21 irradiated with the immediately preceding laser light. The movement of the irradiation area 22 between the processing areas 21 is performed in the order of the arrows a, b, and c shown in FIG. 2. The movement between the processing areas 21 indicated by the arrows a and c is the movement between the processing areas 21 separated from each other in the X direction. This movement is the second step in which the galvanoscanner 361 moves the irradiation area 22 so as to be located within a processing area 21 different from the processing area 21 irradiated with the immediately preceding pulsed laser light. The movement between the processing areas 21 indicated by the arrow b is the movement between the processing areas 21 having different positions in the X and Y directions. In this case, the galvanoscanners 361 and 362 move the irradiation area 22.

[0077] (Step SP17) This step is to stop the movement of the table 351 of the stage 350. This step is performed in step SP15 when the number n is greater than nmax, and is performed after the irradiation of the laser light to all the processing areas 21 is completed. In this step, the laser processing processor 310 controls the stage 350 to stop the movement of the table 351. Thus, the recesses 30 are formed in all the processing areas 21, and the processing of the workpiece 20 is completed.

[0078] 2.3 Function and Effect The laser processing method of the present embodiment includes a first step and a second step. In the first step, the irradiation area 22 is moved by a stage 350 movable in the X direction so as to overlap a part of the irradiation area 22 of the immediately preceding pulsed laser light. In the second step, the irradiation area 22 is moved by a galvanometer scanner 361 movable in the X direction so as to be located within a processing area 21 different from the processing area 21 irradiated with the immediately preceding pulsed laser light. In the laser processing system 10 of the present embodiment, the stage 350 moves the irradiation area 22 so as to overlap a part of the irradiation area 22 of the immediately preceding pulsed laser light. Further, the galvanometer scanner 361 moves the irradiation area 22 so as to be located within a processing area 21 different from the processing area 21 irradiated with the immediately preceding pulsed laser light. The galvanometer scanner 361 that changes the optical path of the pulsed laser light to move the irradiation area 22 can shorten the time required to move the irradiation area 22 compared to the stage 350 that moves the irradiation area 22 by moving a table 351 that supports the workpiece 20. Therefore, according to the laser processing method and the laser processing system 10 of the present embodiment, the processing time can be shortened compared to the case where the stage 350 moves the irradiation area 22 between different processing areas 21.

[0079] Further, according to the laser processing method and the laser processing system 10 of the present embodiment, even if the workpiece 20 is moved in the X direction by the stage 350, the irradiation area 22 can be moved between processing areas 21 spaced apart from each other in the X direction by the galvanometer scanner 361.

[0080] In the laser processing method and the laser processing system 10 of the present embodiment, the two processing areas 21 in the set 26 of the processing areas 21 are spaced apart from each other in the X direction. The direction in which the irradiation area 22 moves in each processing area 21 is a direction from one side to the other side in the X direction. Therefore, the inclined surface 31 in the recess 30 formed for each processing area 21 inclines toward the surface side of the workpiece 20 from one side to the other side in the X direction. Therefore, it is particularly useful when manufacturing an optical waveguide substrate in which such inclined micromirrors are arranged in the X direction.

[0081] Further, the laser processing system 10 of the present embodiment includes a galvanometer scanner 362 capable of moving the irradiation region 22 in the Y direction perpendicular to the X direction. For this reason, even if the workpiece 20 is moved in the X direction by the stage 350, the galvanometer scanners 361 and 362 can move the irradiation region 22 between the processing regions 21 having different positions in the Y direction.

[0082] Also, in the laser processing method of the present embodiment, the workpiece 20 is moved at a constant speed in the X direction by the stage 350 until the processing of all the processing regions 21 is completed. However, in the second step described above, the movement of the workpiece 20 in the X direction by the stage 350 may be stopped. Also, the order of the processing regions 21 irradiated with the laser light is not limited.

[0083] 3. Description of the Laser Processing System and Laser Processing Method of Embodiment 2 Next, the laser processing system 10 and the laser processing method of Embodiment 2 will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted unless otherwise specified.

[0084] 3.1 Configuration FIG. 10 is a schematic diagram showing a schematic configuration example of the laser processing apparatus 300 of the present embodiment. As shown in FIG. 10, the laser processing apparatus 300 of the present embodiment is different from the laser processing apparatus 300 of Embodiment 1 in that it includes a galvanometer scanner 363 as a second galvanometer scanner instead of the high reflection mirror 331b.

[0085] The galvanometer scanner 363 is disposed on the optical path between the mask 335 and the galvanometer scanner 361, and is located upstream of the galvanometer scanner 361 with respect to the traveling direction of the laser beam. The galvanometer scanner 363 includes a drive unit 363a and a mirror 363b attached to the swing axis of the drive unit 363a and swingable around the swing axis. The drive unit 363a can change the direction of the mirror 363b in the same manner as the drive unit 361a of the galvanometer scanner 361. The mirror 363b reflects the laser beam from the mask 335 toward the mirror 361b of the galvanometer scanner 361. The mirror 361b reflects the laser beam from the mirror 363b toward the mirror 362b of the galvanometer scanner 362, and the mirror 362b reflects the laser beam from the mirror 361b toward the fθ lens 370. The fθ lens 370 condenses the laser beam irradiated from the galvanometer scanner 362 onto the surface of the workpiece 20 along the optical axis of the fθ lens 370.

[0086] The galvanometer scanner 363 can change the optical path of the laser beam along the X direction by the mirror 363b and move the irradiation area 22 of the laser beam in the X direction. That is, the galvanometer scanner 363 is a moving unit that can move the irradiation area 22 of the laser beam in the X direction. It is preferable that the minimum moving distance of the irradiation area 22 adjustable by the galvanometer scanner 363 is shorter than the minimum moving distance of the irradiation area 22 adjustable by the galvanometer scanner 361.

[0087] 3.2 Operation Next, the operation of the laser processing processor 310 in the present embodiment will be described.

[0088] FIG. 11 is a diagram showing a control flowchart of the laser processing processor 310 of the present embodiment. The control flowchart of the present embodiment is different from the control flowchart of the first embodiment in that it does not include steps SP12, SP14, and SP17 and includes steps SP21, SP22, and SP23. Therefore, hereinafter, SP21, SP22, and SP23 will be described, and the description of other steps will be omitted as appropriate.

[0089] (Step SP21) This step is performed when the coordinates of the irradiation position become the coordinates of the machining area 21 with number n, and is a step of moving the irradiation area 22 in the X direction by the galvanometer scanner 363. Therefore, at the start of this step, the irradiation area 22 is along one edge of the machining area 21 with number n in the X direction. In this step, the laser processing processor 310 controls the galvanometer scanner 363 so that the irradiation area 22 moves at a constant speed from one side to the other side in the X direction. This control continues until step SP23. When starting this control, the laser processing processor 310 advances the control flow to step SP22.

[0090] (Step SP22) This step is the same as step SP14 in Embodiment 1, and is a step of irradiating the workpiece 20 with laser light at a predetermined time interval. In this step, the laser processing processor 310 transmits the emission trigger Tr and irradiates the workpiece 20 with laser light. During this step, the irradiation area 22 moves toward the other side in the X direction as time passes. In this embodiment, similar to step SP14 in Embodiment 1, the time interval for irradiating the laser light is adjusted so that the irradiation area 22 overlaps a part of the irradiation area 22 irradiated with the immediately previous laser light, and the mmax-th irradiation area 22 is along the other edge of the machining area 21 in the X direction. Therefore, the galvanometer scanner 363 moves the irradiation area 22 so as to overlap a part of the irradiation area 22 irradiated with the immediately previous laser light. Also, this movement is the first step of moving the irradiation area 22 by the galvanometer scanner 363 capable of moving the irradiation area 22 in the X direction so as to overlap a part of the irradiation area 22 irradiated with the immediately previous laser light. When the mmax-th laser light is irradiated, the entire machining area 21 is irradiated with laser light, and the recess 30 is formed in the machining area 21. When performing the irradiation of the mmax-th laser light, the laser processing processor 310 advances the control flow to step SP23.

[0091] (Step SP22) This step is to stop the movement of the irradiation area 22 in the X direction by the galvanometer scanner 363. In this step, the laser processing processor 310 controls the galvanometer scanner 363 to stop the movement of the irradiation area 22. When the laser processing processor 310 stops the movement of the irradiation area 22, it advances the control flow to step SP15.

[0092] 3.3 Function and Effect According to the laser processing method and the laser processing system 10 of this embodiment, similar to the laser processing method and the laser processing system 10 of Embodiment 1, compared with the case where the movement of the irradiation area 22 between different processing areas 21 is performed on the stage 350, the processing time can be shortened. Further, in the laser processing method and the laser processing system 10 of this embodiment, the movement of the irradiation area 22 in the X direction within the processing area 21 is performed by the galvanometer scanner 363, and the movement of the irradiation area 22 between the processing areas 21 separated from each other in the X direction is performed by the galvanometer scanner 361. Therefore, compared with the case where the movement of these irradiation areas 22 is performed by one galvanometer scanner 361, the minimum movement distance of the irradiation area 22 by the galvanometer scanner 363 that moves the irradiation area 22 within the processing area 21 can be reduced, and the processing accuracy of the processing area 21 can be improved.

[0093] Further, in the laser processing method of this embodiment, the movement of the irradiation area 22 in the X direction within the processing area 21 is performed by the galvanometer scanner 363, and the movement of the irradiation area 22 between the processing areas 21 is performed by the galvanometer scanners 361 and 362. Therefore, the workpiece 20 can be processed without moving the workpiece 20. Also, for example, compared with the case where the movement of the irradiation area 22 between the processing areas 21 is performed while moving the workpiece 20 in the X direction at a constant speed, since the movement of the irradiation area 22 between the processing areas 21 can be performed without synchronization with the movement of the workpiece 20, the processing accuracy can be improved.

[0094] Also, the moving distance of the irradiation area 22 in the X direction within the processing area 21 is shorter than the moving distance of the irradiation area 22 between the processing areas 21. Therefore, the maximum amount of change in the optical path of the laser beam by the galvano scanner 363 is smaller than the maximum amount of change in the optical path of the laser beam by the galvano scanner 361. In the present embodiment, since the galvano scanner 363 is located upstream of the galvano scanner 361 with respect to the traveling direction of the laser beam, it is easier for the laser beam to be incident on the galvano scanner 361.

[0095] Note that the galvano scanner 363 may be located downstream of the galvano scanner 361 with respect to the traveling direction of the laser beam. Also, in the present embodiment, since the stage 350 does not move the workpiece 20, the configuration of the stage 350 may be such that the table 351 does not move.

[0096] 4. Description of the Laser Processing System and Laser Processing Method of Embodiment 3 Next, the laser processing system 10 and the laser processing method of Embodiment 3 will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted unless otherwise specified.

[0097] 4.1 Configuration FIG. 12 is a schematic diagram showing a schematic configuration example of the laser processing apparatus 300 of the present embodiment. As shown in FIG. 12, the laser processing apparatus 300 of the present embodiment is different from the laser processing apparatus 300 of Embodiment 2 in that it further includes a splitting optical system 380, a high reflection mirror 331d, galvano scanners 364, 365, 366, and an fθ lens 371.

[0098] The splitting optical system 380 is disposed on the optical path between the mask 335 and the high reflection mirror 331d. The splitting optical system 380 includes, for example, a beam splitter 381, reflects a part of the laser beam from the mask 335 toward the galvano scanner 366, and transmits the rest. In this way, the splitting optical system 380 splits the laser beam from the mask 335 into two laser beams La and Lb.

[0099] The configuration of the high-reflection mirror 331d is the same as that of the high-reflection mirrors 331a, 331b, and 331c, for example. The high-reflection mirror 331d reflects the laser beam La transmitted through the beam splitter 381 toward the galvanometer scanner 363. The mirror 363b of the galvanometer scanner 363 reflects the laser beam La from the high-reflection mirror 331d toward the mirror 361b, and the mirror 361b reflects the laser beam La from the mirror 363b toward the mirror 362b. The mirror 362b reflects the laser beam La from the mirror 361b toward the fθ lens 370. That is, the galvanometer scanners 361, 362, and 363 are provided for the laser beam La. The fθ lens 370 focuses the laser beam La irradiated from the galvanometer scanner 362 onto the surface of the workpiece 20 along the optical axis of the fθ lens 370.

[0100] The configurations of the galvanometer scanners 364, 365, and 366 are the same as those of the galvanometer scanners 361, 362, and 363, and the galvanometer scanners 364, 365, and 366 include drive units 364a, 365a, and 366a and mirrors 364b, 365b, and 366b. The mirror 366b reflects the laser beam Lb reflected by the beam splitter 381 toward the mirror 364b, and the mirror 364b reflects the laser beam Lb from the mirror 366b toward the mirror 365b. The mirror 365b reflects the laser beam Lb from the mirror 364b toward the fθ lens 370. That is, the galvanometer scanners 364, 365, and 366 are provided for the laser beam Lb.

[0101] The galvanometer scanner 364 can change the optical path of the laser beam Lb along the X direction by the mirror 364b, and move the irradiation area 22 of the laser beam Lb in the X direction. The galvanometer scanner 366 can change the optical path of the laser beam Lb along the X direction by the mirror 366b, and move the irradiation area 22 of the laser beam Lb in the X direction. That is, the galvanometer scanners 364 and 366 are moving parts that can move the irradiation area 22 of the laser beam Lb in the X direction. The galvanometer scanner 365 can change the optical path of the laser beam Lb along the Y direction by the mirror 365b, and move the irradiation area 22 of the laser beam Lb in the Y direction. That is, the galvanometer scanner 365 is a moving part that can move the irradiation area 22 of the laser beam Lb in the Y direction.

[0102] The configuration of the fθ lens 371 is the same as that of the fθ lens 370, for example. The fθ lens 371 is disposed on the optical path between the mirror 365b and the workpiece 20, and the optical axis of the fθ lens 371 is along the Z direction. The fθ lens 371 focuses the laser beam Lb irradiated from the galvanometer scanner 365 onto the surface of the workpiece 20 along the optical axis of the fθ lens 371.

[0103] In the present embodiment, among the plurality of processing regions 21 shown in FIG. 2, one set 26 of the processing regions 21 is a region to be processed by the irradiation of the laser beam La from the fθ lens 370, and the other set 26 of the processing regions 21 is a region to be processed by the irradiation of the laser beam Lb from the fθ lens 371. The number of the processing regions 21 in one set 26 is the same as the number of the processing regions 21 in the other set 26.

[0104] 4.2 Operation Next, the operation of the laser processing processor 310 in the present embodiment will be described.

[0105] The control flowchart of the laser processing processor 310 according to this embodiment is the same as the control flowchart of Embodiment 2 shown in FIG. 11. However, the operations of steps SP13, SP21, SP22, and SP23 in this embodiment are different from the operations of steps SP13, SP21, SP22, and SP23 in Embodiment 2. For this reason, hereinafter, SP13, SP21, SP22, and SP23 will be described, and the description of other steps will be omitted as appropriate.

[0106] In this embodiment, the number nmax, number n, and coordinates of the processing region 21 are set for each set 26 of the processing regions 21. Also, the number nmax of the processing regions 21 and the maximum number mmax of irradiating the processing regions 21 with laser light are the same regardless of the set 26 of the processing regions 21.

[0107] (Step SP13) In this step of this embodiment, the laser processing processor 310 controls the galvanoscanners 361 and 362 so that the coordinates of the irradiation position of the laser beam La become the coordinates of the processing region 21 with the number n. Also, the laser processing processor 310 controls the galvanoscanners 364 and 365 so that the coordinates of the irradiation position of the laser beam Lb become the coordinates of the processing region 21 with the number n. When the movement of the irradiation position is performed, the laser processing processor 310 advances the control flow to step SP21.

[0108] (Step SP21) In this step of this embodiment, the laser processing processor 310 controls the galvanoscanner 363 so that the irradiation region 22 of the laser beam La moves at a constant speed from one side to the other side in the X direction. Also, the laser processing processor 310 controls the galvanoscanner 366 so that the irradiation region 22 of the laser beam Lb moves at a constant speed from one side to the other side in the X direction. These controls are continued until step SP23. When starting these controls, the laser processing processor 310 advances the control flow to step SP22.

[0109] (Step SP22) In this step of the present embodiment, the laser processing processor 310 transmits the emission trigger Tr and irradiates the workpiece 20 with the laser beams La and Lb, in the same manner as in step SP22 of Embodiment 2. The laser processing apparatus 300 of the present embodiment includes a splitting optical system 380. Therefore, the laser beams La and Lb split into two by the splitting optical system 380 are simultaneously irradiated onto two of the plurality of processing regions 21, and this simultaneous irradiation is repeated at a predetermined time interval. During this step, the irradiation regions 22 of the laser beam La and the irradiation regions 22 of the laser beam Lb move toward the other side in the X direction as time elapses. The time interval for irradiating the laser beams La and Lb is adjusted in the same manner as in step SP22 of Embodiment 2. Therefore, the irradiation region 22 of the laser beam La overlaps a part of the irradiation region 22 irradiated with the immediately preceding laser beam La, and the irradiation region 22 of the laser beam Lb overlaps a part of the irradiation region 22 irradiated with the immediately preceding laser beam Lb. The irradiation region 22 of the mmax-th laser beam La is along the edge on the other side in the X direction of the processing region 21, and the irradiation region 22 of the mmax-th laser beam Lb is along the edge on the other side in the X direction of the processing region 21. That is, the galvanoscanners 363 and 366 move the irradiation regions 22 of the laser beams La and Lb so as to overlap a part of the irradiation regions 22 of the immediately preceding laser beams La and Lb. Also, this movement is the same as the first step described in Embodiment 2. When the laser processing processor 310 performs the irradiation of the mmax-th laser beams La and Lb, the control flow proceeds to step SP23.

[0110] (Step SP23) In this step of the present embodiment, the laser processing processor 310 controls the galvanoscanners 363 and 366 to stop the movement of the irradiation regions 22 of the laser beams La and Lb. When the laser processing processor 310 stops the movement, the control flow proceeds to step SP15.

[0111] 4.3 Action and Effect According to the laser processing method and the laser processing system 10 of the present embodiment, similar to the laser processing method and the laser processing system 10 of Embodiment 1, the processing time can be shortened as compared with the case where the stage 350 moves the irradiation area 22 between different processing areas 21.

[0112] In addition, in the laser processing method of the present embodiment, the pulse laser light is irradiated simultaneously to two of the plurality of processing areas 21. Therefore, according to the laser processing method of the present embodiment, the processing time can be further shortened.

[0113] Note that the splitting optical system 380 may split the laser light from the mask 335 into three or more laser lights. In this case, for example, three galvanoscanners are provided for each of the split laser lights. According to such a configuration, the pulse laser light can be irradiated simultaneously to three or more of the plurality of processing areas 21. Note that the number of splits of the laser light is preferably not more than half of the number of processing areas 21, and the number of processing areas 21 is preferably an integral multiple of the number of splits of the laser light.

[0114] In addition, the laser processing apparatus 300 may not include the galvanoscanners 363 and 366. In this case, for example, the stage 350 moves the irradiation area 22 in the X direction within the processing area 21.

[0115] Although the present invention has been described by taking the embodiment as an example, the above embodiment can be changed as appropriate. For example, although the outer shape of the laser light irradiated to the workpiece 20 is a rectangular shape that is long in the Y direction, it may be a shape other than the rectangular shape, for example, a circular shape.

[0116] In addition, the laser processing apparatus 300 may not include the fθ lenses 370 and 371.

[0117] The above description is intended as an illustration only and not a limitation. Thus, it will be apparent to those skilled in the art that modifications may be made to the embodiments of the present disclosure without departing from the scope of the claims. It will also be apparent to those skilled in the art that embodiments of the present disclosure may be used in combination. Terms used throughout this specification and the claims should be construed as "non-limiting" terms unless otherwise specified. For example, terms such as "comprising," "having," "including," and "containing" should be construed as not excluding the presence of elements other than those described. Also, the modifier "one" should be construed to mean "at least one" or "one or more." Also, the term "at least one of A, B, and C" should be construed to mean "A," "B," "C," "A + B," "A + C," "B + C," or "A + B + C," and further should be construed to include combinations with things other than "A," "B," and "C."

Claims

1. A laser processing system for forming a plurality of recesses by irradiating a plurality of processing regions spaced apart from each other in a first direction on the surface of a workpiece with pulsed laser light, comprising: A gas laser device that emits the pulsed laser light; A moving unit capable of moving the irradiation region of the pulsed laser light on the surface in the first direction; A first galvanometer scanner capable of changing the optical path of the pulsed laser light to move the irradiation region in the first direction; Comprising; The moving unit moves the irradiation region so as to overlap a part of the irradiation region of the immediately preceding pulsed laser light; The first galvanometer scanner moves the irradiation region so as to be located within a processing region different from the processing region irradiated with the immediately preceding pulsed laser light; Laser processing system.

2. The laser processing system according to claim 1, wherein: The moving unit is a stage including a table that supports the workpiece and is movable in the first direction.

3. The laser processing system according to claim 1, wherein: The moving unit is a second galvanometer scanner that changes the optical path of the pulsed laser light along the first direction.

4. The laser processing system according to claim 3, wherein: The second galvanometer scanner is located upstream of the first galvanometer scanner with respect to the traveling direction of the pulsed laser light.

5. The laser processing system according to claim 4, wherein: The minimum moving distance of the irradiation region adjustable by the second galvanometer scanner is shorter than the minimum moving distance of the irradiation region adjustable by the first galvanometer scanner.

6. The laser processing system according to claim 1, further comprising: A third galvanometer scanner that changes the optical path of the pulsed laser light so that the irradiation region moves in a second direction perpendicular to the first direction.

7. The laser processing system according to claim 6, wherein: The minimum moving distance of the irradiation region adjustable by the moving unit is shorter than the minimum moving distance of the irradiation region adjustable by the third galvanometer scanner.

8. The laser processing system according to claim 1, further comprising: A splitting optical system that splits the pulsed laser light into a plurality of parts, and The first galvanometer scanner is provided for each of the split pulsed laser lights.

9. The laser processing system according to claim 1, wherein: The workpiece is a light-transmissive plate-like member serving as an optical waveguide substrate.

10. The laser processing system according to claim 9, wherein the material constituting the plate-like member is a polyimide resin or a polynorbornene resin.

11. The laser processing system according to claim 1, further comprising an fθ lens that condenses the pulsed laser light on the surface of the workpiece.

12. A laser processing method for irradiating a pulsed laser light onto a plurality of processing regions spaced apart from each other in a first direction on the surface of a workpiece to form a plurality of recesses, comprising: a first step of moving the irradiation region of the pulsed laser light on the surface by a moving unit movable in the first direction so that a part of the irradiation region of the pulsed laser light immediately before overlaps with the irradiation region of the pulsed laser light immediately before in the processing region irradiated with the pulsed laser light immediately before; a second step of moving the irradiation region by a first galvanometer scanner capable of changing the optical path of the pulsed laser light and moving the irradiation region in a first direction so as to be located in a processing region different from the processing region irradiated with the pulsed laser light immediately before; comprising a laser processing method.

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