Laser processing system and laser processing method

Abstract

The invention provides a laser processing system and a laser processing method. A laser processing system for forming a plurality of recesses by irradiating a plurality of processing regions separated from each other in a first direction on the surface of a workpiece with a pulsed laser light, the laser processing system comprising: a gas laser device for emitting a pulsed laser light; a moving unit capable of moving an irradiation region of the pulse laser light on the surface in a first direction; and a first Garvalnol scanner capable of changing the optical path of the pulse laser light to move the irradiation region in the first direction, the moving unit moving the irradiation region so as to overlap with a portion of the irradiation region of the pulse laser light immediately preceding, the first Garvalnol scanner moving the irradiation region so as to overlap with a portion of the irradiation region of the pulse laser light immediately preceding, and the second Garvalnol scanner moving the irradiation region so as to overlap with the portion of the irradiation region. The processing area is different from the processing area irradiated by the immediately preceding pulse laser.

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, with the miniaturization and high integration of semiconductor integrated circuits, an improvement in resolution has been required. Therefore, a reduction in the wavelength of light emitted from an exposure light source has been promoted. For example, as a gas laser device for exposure, a KrF excimer laser device that emits laser light with an output wavelength of about 246.0 nm and an ArF excimer laser device that emits laser light with an output wavelength of about 193.4 nm are used.

[0003] The spectral line widths of the spontaneous oscillation light of KrF excimer laser devices and ArF excimer laser devices are as wide as 350 pm to 400 pm. Therefore, when a projection lens is made of a material that transmits ultraviolet light such as KrF and ArF lasers, chromatic aberration may occur. As a result, the resolution may be reduced. Therefore, it is necessary to narrow the spectral line width of the laser output from the gas laser device to such an extent that chromatic aberration can be ignored. Therefore, in the laser resonator of the gas laser device, in order to narrow the spectral line width, a line narrowing module (LNM) including a line narrowing element (etalon, grating, etc.) is sometimes provided. Hereinafter, a gas laser device whose spectral line width is narrowed will be referred to as a narrowband gas laser device.

[0004] [Prior Art Documents]

[0005] [Patent Documents]

[0006] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2004-230441

[0007] [Patent Document 2] U.S. Patent Application Publication No. 2002 / 0064345 Summary of the Invention

[0008] A laser processing system according to one aspect of the present disclosure may be configured to irradiate a plurality of processing regions separated from each other in a first direction on the surface of a workpiece with pulsed laser light to form a plurality of recesses. The laser processing system includes: a gas laser device that emits pulsed laser light; a moving unit that can move the irradiation region of the pulsed laser light in the first direction on the surface; 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 moves the irradiation region so as to be located in a processing region different from the processing region irradiated by the immediately preceding pulsed laser light.

[0009] One method of laser processing according to the present disclosure may be to irradiate a plurality of processing regions separated from each other in a first direction on the surface of a workpiece with pulsed laser light to form a plurality of recesses. Among them, the laser processing method includes: a first step of moving an irradiation region by a moving unit capable of moving the irradiation region of the pulsed laser light on the surface in the first direction so that it overlaps with a part of the irradiation region of the immediately preceding pulsed laser light within the processing region irradiated by the immediately preceding pulsed laser light; and a second step of moving the irradiation region by a first galvanometer scanner capable of changing the optical path of the pulsed laser light to move the irradiation region in the first direction so that it is located in a processing region different from the processing region irradiated by the immediately preceding pulsed laser light. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Hereinafter, as an example only, several embodiments of the present disclosure will be described with reference to the drawings.

[0011] Figure 1 It is a schematic diagram showing a schematic overall structure example of a laser processing system of a comparative example.

[0012] Figure 2 It is a diagram for explaining the processing order on the surface of the workpiece.

[0013] Figure 3 It is a diagram showing an example of the irradiation region during the first irradiation of the processing region.

[0014] Figure 4 It is a cross-sectional view showing the state of the workpiece after the first irradiation of the processing region.

[0015] Figure 5 It is a diagram showing an example of the irradiation region during the second irradiation of the processing region.

[0016] Figure 6 It is a cross-sectional view showing the state of the workpiece after the second irradiation of the processing region.

[0017] Figure 7 It is a cross-sectional view showing the state of the workpiece after irradiating the entire processing region with laser light.

[0018] Figure 8 It is a schematic diagram showing a schematic overall structure example of the laser processing apparatus of Embodiment 1.

[0019] Figure 9 It is a diagram showing a control flowchart of the laser processing processor of Embodiment 1.

[0020] Figure 10 It is a schematic diagram showing a schematic overall structure example of the laser processing apparatus of Embodiment 2.

[0021] Figure 11This is a diagram showing the control flow of the laser processing processor according to Embodiment 2.

[0022] Figure 12 This is a schematic diagram showing a schematic structure example of the laser processing apparatus according to Embodiment 3. Detailed Embodiments

[0023] 1. Description of the laser processing system and laser processing method of the comparative example

[0024] 1.1 Structure

[0025] 1.2 Operation

[0026] 1.3 Problems

[0027] 2. Description of the laser processing system and laser processing method of Embodiment 1

[0028] 2.1 Structure

[0029] 2.2 Operation

[0030] 2.3 Functions and Effects

[0031] 3. Description of the laser processing system and laser processing method of Embodiment 2

[0032] 3.1 Structure

[0033] 3.2 Operation

[0034] 3.3 Functions and Effects

[0035] 4. Description of the laser processing system and laser processing method of Embodiment 3

[0036] 4.1 Structure

[0037] 4.2 Operation

[0038] 4.3 Functions and Effects

[0039] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and operations described in each embodiment are not necessarily all essential as the structures and operations of the present disclosure. Furthermore, the same reference numerals are assigned to the same components, and repeated descriptions are omitted.

[0040] 1. Description of the laser processing system and laser processing method of the comparative example

[0041] 1.1 Structure

[0042] A laser processing system and a laser processing method of a comparative example will be described. In addition, the comparative example of the present disclosure is a manner known only to the applicant, not a publicly known example that the applicant assumes to be.

[0043] Figure 1 It is a schematic diagram showing a schematic structure example of the whole of the laser processing system 10 of this example. The laser processing system 10 of this example mainly includes a gas laser device 100, a laser processing device 300, and an optical path tube PO connecting the gas laser device 100 and the laser processing device 300. Hereinafter, the direction parallel to the optical axis direction of the laser incident on the workpiece 20 will be set as the Z direction, the first direction orthogonal to the Z direction will be set as the X direction, and the second direction orthogonal to the X direction and the Z direction will be set as the Y direction for explanation. The Z direction is also the height direction of the workpiece 20.

[0044] The gas laser device 100 of this example is an ArF excimer laser device using a mixed gas containing argon (Ar), fluorine (F2), and neon (Ne). The gas laser device 100 outputs a laser with a center wavelength of about 193.4 nm. In addition, the gas laser device 100 may be a gas laser device other than the ArF excimer laser device. For example, it may be a KrF excimer laser device using a mixed gas containing krypton (Kr), F2, and Ne. In this case, the gas laser device 100 emits a laser with a center wavelength of about 246.0 nm. Sometimes, a mixed gas containing Ar, F2, and Ne as a laser medium and a mixed gas containing Kr, F2, and Ne as a laser medium are called laser gases.

[0045] The gas laser device 100 mainly includes a housing 110, a laser oscillator 130 disposed in the internal space of the housing 110, a monitoring module 150, a diaphragm 170, and a laser processor 190.

[0046] The laser oscillator 130 includes a laser chamber 131, a charger 141, a pulse power supply module 143, a rear mirror 145, and an output coupling mirror 147. In Figure 1 It shows the internal structure of the laser chamber 131 observed from a direction substantially perpendicular to the traveling direction of the laser.

[0047] The laser chamber 131 includes an internal space where light is generated by exciting the laser medium in the above-mentioned laser gas. This light travels toward the windows 139a and 139b described later. 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). In addition, the laser gas in the laser chamber 131 is processed to remove F2 gas by a halogen filter, and is exhausted to the housing 110 by an exhaust pump (not shown) through a pipe (not shown).

[0048] Inside the internal space of the laser chamber 131, a pair of electrodes 133a and 133b face each other, and the longitudinal direction of each is arranged along the light traveling direction. Electrodes 133a and 133b are discharge electrodes for exciting the laser medium by glow discharge. In this example, electrode 133a is the cathode and electrode 133b is the anode.

[0049] Electrode 133a is supported by the electrical insulation part 135. The electrical insulation part 135 plugs the opening formed in the laser chamber 131. A conductive part (not shown) is buried in the electrical insulation part 135, and the conductive part applies a high voltage supplied from the pulse power supply module 143 to electrode 133a. Electrode 133b is supported by the return plate 137, and the return plate 137 is connected to the inner surface of the laser chamber 131 through wiring (not shown).

[0050] The charger 141 is a DC power supply device that charges a charging capacitor (not shown) in the pulse power supply module 143 with a prescribed voltage. The pulse power supply module 143 includes a switch 143a controlled by the laser processor 190. When the switch 143a changes from off to on, the pulse power supply module 143 generates a pulsed high voltage based on the electric energy held in the charger 141 and applies this high voltage between electrode 133a and electrode 133b.

[0051] When a high voltage is applied between electrode 133a and electrode 133b, a discharge occurs between electrode 133a and electrode 133b. The energy of this discharge excites the laser medium in the laser chamber 131, and the excited laser medium emits light when it transitions to the ground state.

[0052] Windows 139a and 139b are provided in the laser chamber 131. Window 139a is located on one end side in the light traveling direction in the laser chamber 131, window 139b is located on the other end side in this traveling direction, and windows 139a and 139b sandwich the space between electrode 133a and electrode 133b. Windows 139a and 139b are inclined at the Brewster angle with respect to the light traveling direction to suppress the reflection of the P-polarized light of the laser. The laser oscillated as described later is emitted to the outside of the laser chamber 131 through windows 139a and 139b. As described above, since a pulsed high voltage is applied between electrode 133a and electrode 133b by the pulse power supply module 143, this laser is pulsed laser.

[0053] The rear mirror 145 is disposed inside the inner 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 to return it to the laser chamber 131. The output coupling mirror 147 is disposed inside the inner space of an optical path tube 147a connected to the other end side of the laser chamber 131, allows a part of the laser light emitted from the window 139b to pass through, and reflects the other part of the laser light back to the inner space of the laser chamber 131. In this way, the rear mirror 145 and the output coupling mirror 147 form a Fabry - Perot type laser resonator, and the laser chamber 131 is disposed on the optical path of the laser resonator.

[0054] The monitoring module 150 is disposed on the optical path of the laser light emitted from the output coupling mirror 147. The monitoring module 150 includes, for example, a housing 151, a beam splitter 153 disposed in the inner space of the housing 151, and a light sensor 155. An opening is formed in the housing 151, and the inner space of the housing 151 communicates with the inner space of the optical path tube 147a through this opening.

[0055] The beam splitter 153 allows a part of the laser light emitted from the output coupling mirror 147 to pass through and then directs it toward the diaphragm 170, and reflects the other part of the laser light toward the light - receiving surface of the light sensor 155. The light sensor 155 measures the energy E of the laser light incident on the light - receiving surface. The light sensor 155 outputs a signal representing the measured energy E to the laser processor 190.

[0056] The laser processor 190 of the present disclosure is a processing device including a storage device 190a storing a control program and a CPU (Central Processing Unit) 190b executing the control program. The laser processor 190 is specifically configured or programmed to execute various processes included in the present disclosure. In addition, the laser processor 190 controls the entire gas laser device 100.

[0057] Various signals are transmitted and received between the laser processor 190 and the laser processing processor 310 of the laser processing device 300. For example, the laser processor 190 receives signals such as a light - emission trigger Tr and a target energy Et (described later) from the laser processing processor 310. The laser processor 190 controls the charging voltage of the charger 141 based on the energy E received from the light sensor 155 and the target energy Et received from the laser processing processor 310. By controlling this charging voltage, the energy of the laser is controlled. In addition, the laser processor 190 sends an instruction signal for turning on or off the switch 143a to the pulse power supply module 143. In addition, the laser processor 190 is electrically connected to the diaphragm 170 and controls the opening and closing of the diaphragm 170.

[0058] The laser processor 190 closes the aperture 170 until the difference ΔE between the energy E received from the monitoring module 150 and the target energy Et received from the laser processing processor 310 falls within an allowable range. If the difference ΔE falls within the allowable range, the laser processor 190 sends a reception ready completion signal to the laser processing processor 310 notifying that the reception preparation for the emission trigger Tr has been completed. When receiving the reception ready completion signal, the laser processing processor 310 sends a signal representing the emission trigger Tr to the laser processor 190, and the laser processor 190 opens the aperture 170 when receiving the signal representing the emission trigger Tr. The emission trigger Tr is defined by a specified repetition frequency f and a specified number of pulses P of the laser, is a timing signal for the laser processing processor 310 to cause the laser oscillator 130 to perform laser oscillation, and is an external trigger. The repetition frequency f of the laser is, for example, 1 kHz or more and 10 kHz or less.

[0059] The aperture 170 is disposed on the optical path of the laser that passes through the beam splitter 153 of the monitoring module 150 and then through an opening, and this opening is formed on the side of the housing 151 opposite to the side connected to the optical path tube 147a. In addition, the aperture 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 above-mentioned opening and communicate with the housing 151. In addition, the optical path tube 171 communicates with the laser processing device 300 through the above-mentioned opening of the housing 110 and the optical path tube PO.

[0060] The internal spaces of the optical path tube 171 and the optical path tube 147a, the internal spaces of the housing 151 and the housing 145a are filled with a purge gas. The purge gas contains an inert gas such as nitrogen (N2). The purge gas is supplied from a purge gas supply source (not shown) to the internal spaces of the optical path tube 171 and the optical path tube 147a, the internal spaces of the housing 151 and the housing 145a through a pipe (not shown).

[0061] The laser processing device 300 includes a laser processing processor 310, an optical system 330, a stage 350, a housing 355, and a frame 357 as main structures. 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 an opening formed in the housing 355, and the laser that has passed through the aperture 170 is incident on the housing 355.

[0062] The laser processing processor 310 is a processing device including a storage device 310a storing a control program and a CPU 310b executing 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 device 300.

[0063] The optical system 330 includes high - reflection mirrors 331a, 331b, and 331c, an attenuator 332, a fly - eye lens 333, a converging lens 334, a mask 335, and a projection optical system 336. Each structure of the optical system 330 is fixed to a holding member (not shown) and is arranged at a prescribed position within the housing 355.

[0064] The high - reflection mirrors 331a, 331b, and 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.

[0065] 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, rotary tables 332a, 332b and partial - reflection mirrors 332c, 332d fixed to the rotary tables 332a, 332b. Each of the rotary tables 332a, 332b is electrically connected to the laser processing processor 310 and rotates about the Y - axis according to a control signal from the laser processing processor 310. When the rotary tables 332a, 332b rotate respectively, the partial - reflection mirrors 332c, 332d also rotate respectively. The partial - reflection mirrors 332c, 332d are optical elements whose transmittance varies according to the incident angle of the laser Lb on the partial - reflection mirrors 332c, 332d. By rotating the rotary tables 332a, 332b, the rotation angles of the partial - reflection mirrors 332c, 332d rotating about the Y - axis are adjusted so that the incident angles of the laser light are the same and the transmittance of the partial - reflection mirrors 332c, 332d becomes a desired transmittance. Thereby, the laser light from the high - reflection mirror 331a is reduced to a desired energy and passes through the attenuator 332.

[0066] The fly - eye lens 333 is a lens formed by arranging a plurality of lenses, for example, in a honeycomb pattern, and is also called an integrator lens. The fly - eye lens 333 is arranged such that the focal plane on the emission side of the fly - eye lens 333 coincides with the focal plane on the incident - surface side of the converging lens 334, and emits light in such a way that the energy density of the laser light incident on the converging lens 334 is uniform.

[0067] The converging 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 emission side of the converging lens 334 is located on the mask 335.

[0068] The mask 335 is, for example, a plate-shaped member that forms a through-hole through which a part of the laser passes and blocks the other parts of the laser. In this example, the through-hole is composed of rectangular holes, and by allowing the laser to pass through the through-holes, the outer shape of the laser becomes a rectangle elongated in the Y direction.

[0069] The projection optical system 336 includes, for example, a collimator lens 336a and a condenser lens 336b. The collimator lens 336a emits the laser from the mask 335 as parallel light. The condenser lens 336b condenses the laser from the collimator lens 336a onto the surface of the workpiece 20.

[0070] The mounting table 350 is disposed on the bottom surface of the housing 355 and includes a worktable 351. In addition, the mounting table 350 can move the worktable 351 in the X direction, Y direction, and Z direction according to a control signal from the laser processing processor 310, and can adjust the position of the worktable 351 through this movement.

[0071] The worktable 351 supports the workpiece 20. The main surface of the worktable 351 is substantially orthogonal to the Z axis and substantially along the XY plane. Therefore, the surface and the back surface of the workpiece 20 are substantially orthogonal to the Z axis and are disposed substantially along the XY plane. With the above structure, the mounting table 350 can move the workpiece 20 via the worktable 351 to adjust the position of the workpiece 20 so that the plurality of lasers emitted from the optical system 330 irradiate a desired position of the workpiece 20. That is, the mounting table 350 is a moving part that can move the irradiation area of the laser on the surface of the workpiece 20 in the X direction and Y direction perpendicular to the irradiation direction of the laser.

[0072] The workpiece 20 is an object to be laser-processed by laser irradiation. As the workpiece 20, for example, a light-transmissive plate-shaped member that becomes an optical waveguide substrate can be cited. As the material constituting the plate-shaped member, for example, polyimide resin and polynorbornene resin can be cited.

[0073] During the operation of the laser processing system 10, an inert gas always flows in the internal space of the housing 355. This inert gas is, for example, nitrogen. An inhalation port (not shown) for sucking the inert gas into the housing 355 and an exhaust port (not shown) for discharging the inert gas from the housing 355 are provided in the housing 355. An intake pipe and an exhaust pipe (not shown) are connected to the inhalation port and the exhaust port. A gas supply source (not shown) for supplying the inert gas is connected to the inhalation port through a pipe. The inert gas supplied from the inhalation port also flows into the optical path tube PO communicating with the housing 355.

[0074] 1.2 Operation

[0075] Next, the operation of the laser processing system 10 of the comparative example and the laser processing method will be described.

[0076] In the gas laser device 100, in a state before the gas laser device 100 emits laser light, purge gas is filled into the internal spaces of the optical path tube 147a, 171, PO, and the internal spaces of the housings 145a, 151 from a purge gas supply source (not shown). In addition, laser gas is supplied into the internal space of the laser chamber 131 from a laser gas supply source (not shown). Further, in the laser processing device 300, an inert gas such as nitrogen flows in the internal space of the housing 355.

[0077] In the laser processing device 300, the workpiece 20 is supported on the worktable 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 portion on the mounting table 350. Thereby, the mounting table 350 moves the worktable 351 together with the workpiece 20 to the set initial irradiation position. In addition, the irradiation position refers to the position of the center of the irradiation region where the laser light is irradiated.

[0078] After the worktable 351 moves, 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 to the workpiece 20 becomes the desired energy density F required for laser processing. The energy density F is defined as a value obtained by dividing the energy of the laser by the cross-sectional area of the laser perpendicular to the optical axis of the laser.

[0079] The laser processor 190 closes the aperture 170 and drives the charger 141. In addition, the laser processor 190 turns on the switch 143a of the pulse power supply module 143. Thereby, the pulse power supply module 143 applies a pulsed high voltage between the electrode 133a and the electrode 133b using the electric energy held in the charger 141. Due to this high voltage, 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 becomes an excited state, and light is emitted when the laser medium returns to the ground state. Due to this light, optical resonance occurs between the rear mirror 145 and the output coupler 147, and the light is amplified each time it passes through the discharge space in the internal space of the laser chamber 131, causing laser oscillation. Then, a part of the laser light passes through the output coupler 147 as pulsed laser light and travels toward the beam splitter 153.

[0080] A part of the laser that travels 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 and outputs a signal representing 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 falls within an allowable range. After the difference ΔE falls within the allowable range, the laser processor 190 sends 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.

[0081] When the laser processing processor 310 receives the reception preparation completion signal, it sends the light emission trigger Tr to the laser processor 190. When the laser processor 190 opens the aperture 170 in synchronization with the reception of the light emission trigger Tr, the laser that has passed through the aperture 170 enters the laser processing device 300. This laser is, for example, a pulsed laser with a central wavelength of 193.4 nm.

[0082] The laser that enters the laser processing device 300 is irradiated onto the mask 335 via the high reflection mirror 331a, the attenuator 332, the high reflection mirrors 331b, 331c, the fly-eye lens 333, and the converging lens 334. At this time, the laser is Kohler illuminated onto the mask 335. In the mask 335, a part of the laser passes through the through hole and becomes a laser with a rectangular shape that is long in the Y direction, and the other part of the laser is blocked. The laser that has passed through the mask 335 is made parallel light by the collimating lens 336a of the projection optical system 336 and is focused on the surface of the workpiece 20 by the condensing lens 336b.

[0083] The laser is irradiated onto the workpiece 20 according to the light emission trigger Tr specified by the repetition frequency f and the number of pulses P required for laser processing. Near the surface of the workpiece 20, ablation occurs due to the irradiation of the laser, and defects are generated. Thus, the processed part of the workpiece 20 is processed to form a recess. In this example, a plurality of mutually separated processed parts are processed to form a plurality of recesses.

[0084] Figure 2 It is a diagram for explaining the processing sequence on the surface of the workpiece 20. Figure 2 The shown processing area 21 is an area where the laser is irradiated for processing. A group 26 composed of a plurality of processing areas 21 separated from each other in the X direction is arranged in the Y direction. In this example, an example in which the number of groups 26 is two and the number of processing areas 21 in the group 26 is two is shown, but the number of groups 26 and the number of processing areas 21 in the group 26 are not limited.

[0085] The outer shape of the processing area 21 in this example is a substantially rectangular shape including opposite sides opposed in the X direction and opposite sides opposed in the Y direction. The width of the processing area 21 in the Y direction is substantially the same as the width of the irradiation area 22 irradiated with a single laser pulse in the Y direction, and the width of the processing area 21 in the X direction is wider than the width of the irradiation area 22 in the X direction, being approximately twice that width. Therefore, by irradiating the laser multiple times, the entire processing area 21 is irradiated with the laser. In Figure 2 a shadow composed of multiple dots is added to the irradiation area 22 to distinguish the processing area 21 from the irradiation area 22.

[0086] Figure 3 FIG. is an example of the irradiation area 22 in the first irradiation of the processing area 21, Figure 4 and is a cross-sectional view showing the state of the workpiece 20 after the first irradiation of the processing area 21. As Figure 3 shown, in this example, first, the workpiece 20 is moved by the mounting table 350 so that the irradiation area 22 is along one edge of the processing area 21 in the X direction, and the surface of the workpiece 20 is irradiated with the laser. Therefore, the laser is irradiated onto the irradiation area 22, and as Figure 4 shown, a recess 25 is formed in the workpiece 20.

[0087] Figure 5 FIG. is an example of the irradiation area 22 in the second irradiation of the processing area 21, Figure 6 and is a cross-sectional view showing the state of the workpiece 20 after the second irradiation of the processing area 21. After the first irradiation of the processing area 21, as Figure 5 shown, the workpiece 20 is moved to one side in the X direction by the mounting table 350, and the surface of the workpiece 20 is irradiated with the laser. The irradiation area 22a of the laser irradiated at this time overlaps a part of the irradiation area 22 of the laser irradiated immediately before, and the center 23a of the irradiation area 22a is located on the other side in the X direction than the center 23 of the irradiation area 22. The irradiation area 22a is a region after the irradiation area 22a overlapping with the irradiation area 22 is moved in the short side direction of the outer shape of the laser. In addition, the direction from the center 23a of the irradiation area 22a to the center 23 of the irradiation area 22 overlapping with the irradiation area 22a is the X direction, and the width of the processing area 21 in this X direction is twice the width in the short side direction of the laser. In Figure 5 order to distinguish the irradiation area 22 from the irradiation area 22a, a shadow composed of multiple dots is added to the irradiation area 22, and a shadow composed of multiple oblique lines is added to the irradiation area 22a.

[0088] By irradiating the laser onto the irradiation area 22a, as Figure 6As shown, additional recesses 25 are formed in the workpiece 20. Since the irradiation area 22a overlaps a part of the irradiation area 22 of the immediately preceding laser irradiation, a part of the edge of the irradiation area 22 is located within the irradiation area 22a. Corners are more easily processed by laser than planar portions. Therefore, the corners along the edge of the irradiation area 22 located within the irradiation area 22a are more easily processed than other portions and become chamfered shapes.

[0089] Figure 7 FIG. is a cross-sectional view showing the workpiece 20 after the entire machining area 21 is irradiated with laser. The movement of the irradiation area 22 of the laser and the irradiation with the laser are repeated until the irradiation area 22 of the laser reaches the other edge of the machining area 21 in the X direction. In this way, the recesses 30 shown are formed by forming a plurality of recesses 25. As described above, corners are more easily processed by laser than planar portions, and the other side portion in the X direction of the edge of the recess 25 is irradiated with laser multiple times. Therefore, the other side portion in the X direction of the edge of the recess 30 becomes a substantially flat inclined surface 31, and the one side portion in the X direction of the edge of the recess 30 becomes stepped. The inclined surface 31 is the surface of the optical waveguide substrate provided with the reflective film that becomes the micromirror. In this example, the recess 30 is not a through hole that penetrates to the back surface of the workpiece 20, but it may also be a through hole. Figure 7 Next, the workpiece 20 is moved by the mounting table 350 so that the irradiation area 22 is along the one edge of the other machining area 21 in the X direction, and the laser irradiation and the movement of the irradiation area 22 are repeated. In this example, the machining area 21 irradiated with laser is changed in the order of the arrows a, b, and c shown. In this way, a plurality of recesses 30 are formed in the workpiece 20. In each machining area 21, the direction in which the irradiation area 22 moves is from one side to the other side in the X direction. Therefore, the inclined surface 31 at the recess 30 formed for each machining area 21 is inclined toward the surface side of the workpiece 20 from one side to the other side in the X direction.

[0090] Then, the workpiece 20 is moved by the mounting table 350 so that the irradiation area 22 is along the one edge of the other machining area 21 in the X direction, and the laser irradiation and the movement of the irradiation area 22 are repeated. In this example, the machining area 21 irradiated with laser is changed in the order of the arrows a, b, and c shown. In this way, a plurality of recesses 30 are formed in the workpiece 20. In each machining area 21, the direction in which the irradiation area 22 moves is from one side to the other side in the X direction. Therefore, the inclined surface 31 at the recess 30 formed for each machining area 21 is inclined toward the surface side of the workpiece 20 from one side to the other side in the X direction. Figure 2 As shown, the machining area 21 irradiated with laser is changed in the order of the arrow a, the arrow b, and the arrow c. In this way, a plurality of recesses 30 are formed in the workpiece 20. In each machining area 21, the direction in which the irradiation area 22 moves is from one side to the other side in the X direction. Therefore, the inclined surface 31 at the recess 30 formed for each machining area 21 is inclined toward the surface side of the workpiece 20 from one side to the other side in the X direction.

[0091] 1.3 Problems

[0092] The movement distance of the irradiation area 22 between different machining areas 21 is longer than the movement distance of the irradiation area 22 within the same machining area 21. Therefore, the movement of the irradiation area 22 between the machining areas 21 requires more time and the machining time is longer.

[0093] Therefore, in the following embodiments, a laser processing system 10 and a laser processing method capable of shortening the processing time are exemplified.

[0094] 2. Description of the Laser Processing System and Laser Processing Method of Embodiment 1

[0095] The laser processing system 10 and the laser processing method of Embodiment 1 will be described. In addition, the same reference numerals are given to the structures having the same structure as those described above, and redundant descriptions are omitted unless otherwise specified.

[0096] 2.1 Structure

[0097] Figure 8 It is a schematic diagram showing a schematic structure example of the laser processing apparatus 300 of the present embodiment. As Figure 8 shown, in the laser processing apparatus 300 of the present embodiment, the arrangements of the fly-eye lens 333, the converging lens 334, and the mask 335 are different from those in the laser processing apparatus 300 of the comparative example. In addition, 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 in place of the high reflector 331c, and includes an fθ lens 370 in place of the projection optical system 336.

[0098] The fly-eye lens 333, the converging lens 334, and the mask 335 are arranged on the optical path between the attenuator 332 and the high reflector 331b.

[0099] The galvanometer scanner 361 includes a drive unit 361a and a mirror 361b that is mounted on the swing axis of the drive unit 361a and can swing around the swing axis. In addition, the structure of the galvanometer scanner 362 is the same as that of the galvanometer scanner 361. The galvanometer scanner 362 includes a drive unit 362a and a mirror 362b that is mounted on the swing axis of the drive unit 362a and can swing around the swing axis.

[0100] 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 a control signal 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.

[0101] The mirror 361b reflects the laser light from the high reflector 331b toward the mirror 362b, and the mirror 362b reflects the laser light from the mirror 361b toward the fθ lens 370. The orientations of the mirrors 361b and 362b are adjusted by the swing angles of the swing axes of the drive units 361a and 362a, respectively. The adjustment of the orientations of the mirrors 361b and 362b can also 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.

[0102] The galvanometer scanner 361 changes the optical path of the laser along the X direction through the mirror 361b, and can move the irradiation area 22 of the laser in the X direction. The galvanometer scanner 362 changes the optical path of the laser along the Y direction through the mirror 362b, and can move the irradiation area 22 of the laser in the Y direction. That is, the galvanometer scanner 361 is a moving part that can move the irradiation area 22 of the laser in the X direction perpendicular to the irradiation direction of the laser. In addition, the galvanometer scanner 362 is a moving part that can move the irradiation area 22 of the laser in the Y direction perpendicular to the irradiation direction of the laser. The minimum moving distance of the irradiation area 22 that the galvanometer scanner 361 can adjust is substantially the same as the minimum moving distance of the irradiation area 22 that the galvanometer scanner 362 can adjust. In addition, preferably, the minimum moving distance of the irradiation area 22 in the X direction that the stage 350 can adjust is shorter than the minimum moving distance of the irradiation area 22 that the galvanometer scanner 361 can adjust. In addition, preferably, the minimum moving distance of the irradiation area 22 in the Y direction that the stage 350 can adjust is shorter than the minimum moving distance of the irradiation area 22 that the galvanometer scanner 362 can adjust. In addition, there is no limitation on the length relationship of these minimum moving distances.

[0103] The fθ lens 370 is fixed to a holding member (not shown) on the optical path between the mirror 362b and the workpiece 20, and is disposed at a specified 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 irradiated from the galvanometer scanner 362 onto the surface of the workpiece 20 along the optical axis of the fθ lens 370.

[0104] 2.2 Operations

[0105] Next, the operations of the laser processing processor 310 in the present embodiment will be described.

[0106] Figure 9 is a diagram showing the control flow of the laser processing processor 310 of the present embodiment. The control flow of the present embodiment includes steps SP11 to SP17, and represents a laser processing method for forming a plurality of recesses 30 in the workpiece 20.

[0107] In Figure 9 In the starting state shown, the laser processing processor 310 has received the reception ready completion signal from the laser processor 190, but has not sent the light emission trigger Tr to the laser processor 190. Therefore, the laser is emitted from the laser oscillator 130, but since the aperture 170 is closed, the laser does not enter the laser processing apparatus 300 from the gas laser apparatus 100. In addition, in the starting state, the workpiece 20 has already been supported on the worktable 351.

[0108] (Step SP11)

[0109] This step is a preparation step before the laser processing apparatus 300 operates officially. In this step, the laser processing processor 310 reads parameters from the storage device 310a. The parameters of this embodiment include the number nmax of the processing regions 21, the maximum number mmax of times of irradiating the laser to each processing region 21, the number n, and the coordinates of the processing region 21.

[0110] The processing regions 21 are labeled with numbers from 1 to nmax. The number n is the number of the processing region 21, and the initial value of n is 1. In this embodiment, the numbers increase in the order of the arrow a, arrow b, and arrow c as shown. Figure 2 As shown, the coordinates of the processing region 21 are the XY coordinates of the center 23 of the irradiation region 22 at one side along the X direction of the processing region 21. Figure 3 As shown, the coordinates of the processing region 21 are the XY coordinates of the center 23 of the irradiation region 22 at one side along the X direction of the processing region 21.

[0111] (Step SP12)

[0112] This step is a step of moving the workbench 351 of the stage 350. In this step, the laser processing processor 310 controls the stage 350 to move the workbench 351 from the other side to one side in the X direction at a constant speed. This control continues until step SP16. After starting this control, the laser processing processor 310 makes the control flow enter step SP13.

[0113] (Step SP13)

[0114] This step is a step of moving the irradiation position of the laser. In this step, the laser processing processor 310 controls the galvanometer scanners 361 and 362 to make the coordinates of the irradiation position be the coordinates of the processing region 21 with the number n. The coordinates of the irradiation position are the XY coordinates of the center 23 of the irradiation region 22 when irradiating the laser. After moving the irradiation position, the laser processing processor 310 makes the control flow enter step SP14.

[0115] (Step SP14)

[0116] This step is a step of irradiating the workpiece 20 with a laser at a specified time interval. In this step, the laser processing processor 310 sends a light emission trigger Tr to the laser processor 190 to cause the laser processor 190 to open the aperture 170. As a result, the laser enters the laser processing apparatus 300 from the gas laser apparatus 100. The incident laser travels in the order of the high reflector 331a, the attenuator 332, the converging lens 334, the mask 335, the high reflector 331b, the mirror 361b, the mirror 362b, and the fθ lens 370, and irradiates the workpiece 20. The workpiece 20 is processed by the irradiation of the laser. In this step, since the worktable 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. Therefore, the irradiation area 22 moves toward the other side in the X direction over time. In the present embodiment, the time interval of the irradiated laser is adjusted so that a part of the irradiation area 22 overlaps with a part of the irradiation area 22 irradiated by the immediately preceding laser, and the irradiation area 22 of the mmax-th time is along the edge on the other side in the X direction of the processing area 21. Therefore, the mounting table 350 moves the irradiation area 22 so as to overlap with a part of the irradiation area 22 of the immediately preceding laser. In addition, this movement is the first process in which the mounting table 350 capable of moving the irradiation area 22 in the X direction moves the irradiation area 22 so as to overlap with a part of the irradiation area 22 of the immediately preceding laser, and this first process and the irradiation of the laser are repeated. By irradiating the laser mmax times, the entire processing area 21 is irradiated with the laser, and a recess 30 is formed in the processing area 21. After the mmax-th laser irradiation is performed, the laser processing processor 310 causes the control flow to enter step SP15.

[0117] (Step SP15)

[0118] This step is a step of incrementing the number n by 1. In this step, the laser processing processor 310 rewrites the number n to n + 1 and causes the control flow to enter step SP16.

[0119] (Step SP16)

[0120] This step is a step of making the next step different according to the number n. In this step, the laser processing processor 310 causes the control flow to return to step SP13 when the number n is less than or equal to nmax, and causes the control flow to enter step SP17 when the number n is greater than nmax. Therefore, when there is a processing area 21 that has not been irradiated with the laser, the galvanometer scanners 361 and 362 move the irradiation area 22 so that it is located in a processing area 21 different from the processing area 21 irradiated by the immediately preceding laser. Such movement of the irradiation area 22 between the processing areas 21 is in accordance with Figure 2It is carried out in the order of arrow a, arrow b, and arrow c shown. The movement between the machining areas 21 shown by arrow a and arrow c is the movement between the machining areas 21 separated from each other in the X direction. This movement is the second process in which the irradiation area 22 is moved by the galvanometer scanner 361 to be located within a machining area 21 different from the machining area 21 irradiated by the immediately preceding pulsed laser. In addition, the movement between the machining areas 21 shown by arrow b is the movement between the machining areas 21 with different positions in the X direction and the Y direction. In this case, the irradiation area 22 is moved by the galvanometer scanners 361 and 362.

[0121] (Step SP17)

[0122] This step is to stop the movement of the worktable 351 of the mounting table 350. This step is carried out when the number n is greater than nmax in step SP15 and is carried out after the irradiation of the laser to all the machining areas 21 is completed. In this step, the laser processing processor 310 controls the mounting table 350 to stop the movement of the worktable 351. In this way, the recesses 30 are formed in all the machining areas 21, and the machining of the workpiece 20 is completed.

[0123] 2.3 Function and Effect

[0124] The laser processing method of the present embodiment includes a first process and a second process. In the first process, the irradiation area 22 is moved by the mounting table 350 capable of moving in the X direction so that the irradiation area 22 overlaps with a part of the irradiation area 22 of the immediately preceding pulsed laser. In the second process, the irradiation area 22 is moved by the galvanometer scanner 361 capable of moving in the X direction so that it is located within a machining area 21 different from the machining area 21 irradiated by the immediately preceding pulsed laser. In the laser processing system 10 of the present embodiment, the mounting table 350 moves the irradiation area 22 so that it overlaps with a part of the irradiation area 22 of the immediately preceding pulsed laser. In addition, the galvanometer scanner 361 moves the irradiation area 22 so that it is located within a machining area 21 different from the machining area 21 irradiated by the immediately preceding pulsed laser. The galvanometer scanner 361 that changes the optical path of the pulsed laser to move the irradiation area 22 can shorten the time taken to move the irradiation area 22 compared with the mounting table 350 that moves the irradiation area 22 by moving the worktable 351 that supports the workpiece 20. Therefore, according to the laser processing method and the laser processing system 10 of the present embodiment, compared with the case where the irradiation area 22 is moved between different machining areas 21 by the mounting table 350, the processing time can be shortened.

[0125] In addition, in the laser processing method and the laser processing system 10 according to the present embodiment, even if the object to be processed 20 is moved in the X direction by the mounting table 350, the irradiation area 22 can be moved between the processing areas 21 separated from each other in the X direction by the galvanometer scanner 361.

[0126] In addition, in the laser processing method and the laser processing system 10 of the present embodiment, two processing areas 21 in the group 26 of the processing areas 21 are separated from each other in the X direction. In each processing area 21, the direction in which the irradiation area 22 moves is a direction from one side in the X direction toward the other side. Therefore, the inclined surface 31 at the concave portion 30 formed in each processing area 21 is inclined toward the surface side of the object to be processed 20 from one side in the X direction toward the other side. Therefore, it is particularly useful when manufacturing an optical waveguide substrate in which such inclined micromirrors are arranged in the X direction.

[0127] In addition, the laser processing system 10 of the present embodiment includes a galvanometer scanner 362 capable of moving the irradiation area 22 in the Y direction perpendicular to the X direction. Therefore, even if the object to be processed 20 is moved in the X direction by the mounting table 350, the irradiation area 22 can be moved between the processing areas 21 having different positions in the Y direction by the galvanometer scanners 361 and 362.

[0128] In addition, in the laser processing method of the present embodiment, the object to be processed 20 is moved at a constant speed in the X direction by the mounting table 350 until the processing of all the processing areas 21 is completed. However, in the above-described second step, the movement of the object to be processed 20 in the X direction by the mounting table 350 may be stopped. In addition, the order of the processing areas 21 irradiated with the laser is not limited.

[0129] 3. Description of the Laser Processing System and the Laser Processing Method of Embodiment 2

[0130] Next, the laser processing system 10 and the laser processing method of Embodiment 2 will be described. In addition, the same reference numerals are given to the structures that are the same as those described above, and redundant descriptions are omitted unless otherwise specified.

[0131] 3.1 Structure

[0132] Figure 10 It is a schematic diagram showing a schematic structural example of the laser processing apparatus 300 of the present embodiment. As Figure 10 shown, 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.

[0133] 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 in the traveling direction of the laser. The galvanometer scanner 363 includes a drive unit 363a and a mirror 363b that is mounted on a swing axis of the drive unit 363a and can swing about the swing axis. The drive unit 363a can change the orientation of the mirror 363b in the same manner as the drive unit 361a of the galvanometer scanner 361. The mirror 363b reflects the laser light from the mask 335 toward the mirror 361b of the galvanometer scanner 361. The mirror 361b reflects the laser light from the mirror 363b toward the mirror 362b of the galvanometer scanner 362, and the mirror 362b reflects the laser light from the mirror 361b toward the fθ lens 370. 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.

[0134] The galvanometer scanner 363 can change the optical path of the laser along the X direction by the mirror 363b, so that the irradiation area 22 of the laser moves in the X direction. That is, the galvanometer scanner 363 is a moving unit that can move the irradiation area 22 of the laser in the X direction. Preferably, the minimum moving distance of the irradiation area 22 that the galvanometer scanner 363 can adjust is shorter than the minimum moving distance of the irradiation area 22 that the galvanometer scanner 361 can adjust.

[0135] 3.2 Operation

[0136] Next, the operation of the laser processing processor 310 in the present embodiment will be described.

[0137] Figure 11 It is a diagram showing the control flow of the laser processing processor 310 of the present embodiment. The difference between the control flow of the present embodiment and the control flow of Embodiment 1 is that steps SP12, SP14, and SP17 are not included, and steps SP21, SP22, and SP23 are included. Therefore, SP21, SP22, and SP23 will be described below, and the description of other steps will be omitted as appropriate.

[0138] (Step SP21)

[0139] This step is performed when the coordinates of the irradiation position become the coordinates of the processing area 21 numbered n, and it 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 the edge on one side in the X direction of the processing area 21 numbered n. In this step, the laser processing processor 310 controls the galvanometer scanner 363 to move the irradiation area 22 at a constant speed from one side to the other side in the X direction. This control continues until step SP23. After starting this control, the laser processing processor 310 causes the control flow to enter step SP22.

[0140] (Step SP22)

[0141] This step is the same as step SP14 of Embodiment 1, and it is a step of irradiating the workpiece 20 with laser at a prescribed time interval. In this step, the laser processing processor 310 sends out the emission trigger Tr and irradiates the workpiece 20 with laser. In 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 of Embodiment 1, the time interval of the irradiated laser is adjusted so that a part of the irradiation area 22 overlaps with the irradiation area 22 irradiated by the immediately preceding laser, and the irradiation area 22 at the m_max-th time is along the edge on the other side in the X direction of the processing area 21. Therefore, the galvanometer scanner 363 moves the irradiation area 22 so that a part of it overlaps with the irradiation area 22 of the immediately preceding laser. In addition, this movement is the first process in which the galvanometer scanner 363 capable of moving the irradiation area 22 in the X direction moves the irradiation area 22 so that a part of it overlaps with the irradiation area 22 of the immediately preceding laser. By irradiating the m_max-th laser, the entire processing area 21 is irradiated with laser, and a recess 30 is formed in this processing area 21. After performing the m_max-th laser irradiation, the laser processing processor 310 causes the control flow to enter step SP23.

[0142] (Step SP22)

[0143] This step is a step of stopping 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. After stopping the movement of the irradiation area 22, the laser processing processor 310 causes the control flow to enter step SP15.

[0144] 3.3 Function and Effect

[0145] The laser processing method and the laser processing system 10 according to the present embodiment, similar to the laser processing method and the laser processing system 10 of Embodiment 1, can shorten the processing time compared with the case where the irradiation area 22 is moved between different processing areas 21 by the mounting table 350. In addition, in the laser processing method and the laser processing system 10 of the present embodiment, the irradiation area 22 in the X direction within the processing area 21 is moved by the galvanometer scanner 363, and the irradiation area 22 is moved between the processing areas 21 separated from each other in the X direction by the galvanometer scanner 361. Therefore, compared with the case where these irradiation areas 22 are moved by one galvanometer scanner 361, the minimum moving distance of the irradiation area 22 performed 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.

[0146] In addition, in the laser processing method of the present embodiment, the irradiation area 22 within the processing area 21 is moved in the X direction by the galvanometer scanner 363, and the irradiation area 22 is moved between the processing areas 21 by the galvanometer scanners 361 and 362. Therefore, the workpiece 20 can be processed without moving the workpiece 20. In addition, for example, compared with the case where the irradiation area 22 is moved between the processing areas 21 while the workpiece 20 is moved at a constant speed in the X direction, the irradiation area 22 can be moved between the processing areas 21 without synchronizing with the movement of the workpiece 20, so the processing accuracy can be improved.

[0147] In addition, 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 change amount of the optical path of the laser passing through the galvanometer scanner 363 is smaller than the maximum change amount of the optical path of the laser passing through the galvanometer scanner 361. In the present embodiment, the galvanometer scanner 363 is located upstream of the galvanometer scanner 361 in the traveling direction of the laser, so it is easy to make the laser incident on the galvanometer scanner 361.

[0148] In addition, the galvanometer scanner 363 may also be located downstream of the galvanometer scanner 361 in the traveling direction of the laser. In addition, in the present embodiment, since the workpiece 20 is not moved by the mounting table 350, the structure of the mounting table 350 may also be a structure in which the workbench 351 does not move.

[0149] 4. Description of the laser processing system and the laser processing method of Embodiment 3

[0150] Next, the laser processing system 10 and the laser processing method of Embodiment 3 will be described. In addition, the same reference numerals are assigned to the structures that are the same as those described above, and redundant descriptions are omitted unless otherwise specified.

[0151] 4.1 Structure

[0152] Figure 12 is a schematic diagram showing a schematic structure example of the laser processing apparatus 300 of the present embodiment. As Figure 12 shown, the difference between the laser processing apparatus 300 of the present embodiment and the laser processing apparatus 300 of Embodiment 2 is that it further includes a splitting optical system 380, a high reflector 331d, galvanometer scanners 364, 365, 366, and an fθ lens 371.

[0153] The splitting optical system 380 is disposed on the optical path between the mask 335 and the high reflector 331d. The splitting optical system 380 includes, for example, a beam splitter 381 that reflects a part of the laser light from the mask 335 toward the galvanometer scanner 366 and transmits the remaining part. In this way, the splitting optical system 380 splits the laser light from the mask 335 into two laser beams La and Lb.

[0154] The structure of the high reflector 331d is, for example, the same as the structures of the high reflectors 331a, 331b, and 331c. The high reflector 331d reflects the laser beam La that has passed 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 reflector 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.

[0155] The structures of the galvanometer scanners 364, 365, and 366 are the same as the structures of the galvanometer scanners 361, 362, and 363. 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.

[0156] The galvanometer scanner 364 can change the optical path of the laser Lb along the X direction through the mirror 364b to move the irradiation area 22 of the laser Lb in the X direction. The galvanometer scanner 366 can change the optical path of the laser Lb along the X direction through the mirror 366b to move the irradiation area 22 of the laser 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 Lb in the X direction. The galvanometer scanner 365 can change the optical path of the laser Lb along the Y direction through the mirror 365b to move the irradiation area 22 of the laser 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 Lb in the Y direction.

[0157] The structure of the fθ lens 371 is, for example, the same as that of the fθ lens 370. The fθ lens 371 is arranged 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 Lb irradiated from the galvanometer scanner 365 onto the surface of the workpiece 20 along the optical axis of the fθ lens 371.

[0158] In this embodiment, Figure 2 One group 26 of the processing areas 21 shown is the area processed by the irradiation of the laser La from the fθ lens 370, and the other group 26 of the processing areas 21 is the area processed by the irradiation of the laser Lb from the fθ lens 371. The number of the processing areas 21 in one group 26 is the same as the number of the processing areas 21 in the other group 26.

[0159] 4.2 Operations

[0160] Next, the operations of the laser processing processor 310 in this embodiment will be described.

[0161] The control flow of the laser processing processor 310 in this embodiment is the same as Figure 11 the control flow of the embodiment 2 shown. 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. Therefore, SP13, SP21, SP22, and SP23 will be described below, and the description of other steps will be appropriately omitted.

[0162] In this embodiment, the number nmax, the number n, and the coordinates of the processing area 21 are set for each group 26 of the processing areas 21. In addition, the number nmax of the processing areas 21 and the maximum number mmax of irradiating the laser to the processing area 21 are the same, regardless of the group 26 of the processing areas 21.

[0163] (Step SP13)

[0164] In this step of the present embodiment, the laser processing processor 310 controls the galvanometer scanners 361 and 362 so that the coordinates of the irradiation position of the laser La become the coordinates of the processing area 21 numbered n. In addition, the laser processing processor 310 controls the galvanometer scanners 364 and 365 so that the coordinates of the irradiation position of the laser Lb become the coordinates of the processing area 21 numbered n. After the irradiation position is moved, the laser processing processor 310 causes the control flow to enter step SP21.

[0165] (Step SP21)

[0166] In this step of the present embodiment, the laser processing processor 310 controls the galvanometer scanner 363 so that the irradiation area 22 of the laser La moves at a constant speed from one side to the other side in the X direction. In addition, the laser processing processor 310 controls the galvanometer scanner 366 so that the irradiation area 22 of the laser Lb moves at a constant speed from one side to the other side in the X direction. These controls continue until step SP23. After starting these controls, the laser processing processor 310 causes the control flow to enter step SP22.

[0167] (Step SP22)

[0168] In this step of the present embodiment, the laser processing processor 310 transmits a light emission trigger Tr in the same manner as in step SP22 of Embodiment 2, and irradiates the workpiece 20 with lasers La and Lb. The laser processing apparatus 300 of the present embodiment includes a splitting optical system 380. Therefore, the lasers La and Lb split into two beams 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. In this step, the irradiation regions 22 of the laser La and the irradiation region 22 of the laser Lb move toward the other side in the X direction as time passes. The time interval for irradiating the lasers La and Lb is adjusted in the same manner as in step SP22 of Embodiment 2. Therefore, a part of the irradiation region 22 of the laser La overlaps with a part of the irradiation region 22 irradiated by the immediately preceding laser La, and a part of the irradiation region 22 of the laser Lb overlaps with a part of the irradiation region 22 irradiated by the immediately preceding laser Lb. The irradiation region 22 of the mmax-th laser 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 Lb is along the edge on the other side in the X direction of the processing region 21. That is, the galvanometer scanners 363 and 366 move the irradiation regions 22 of the lasers La and Lb so as to overlap with a part of the irradiation regions 22 of the immediately preceding lasers La and Lb. In addition, this movement is the same as the first process described in Embodiment 2. After the mmax-th irradiations of the lasers La and Lb are performed, the laser processing processor 310 advances the control flow to step SP23.

[0169] (Step SP23)

[0170] In this step of the present embodiment, the laser processing processor 310 controls the galvanometer scanners 363 and 366 to stop the movement of the irradiation regions 22 of the lasers La and Lb. After stopping this movement, the laser processing processor 310 advances the control flow to step SP15.

[0171] 4.3 Function and Effect

[0172] 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 compared with the case where the movement of the irradiation region 22 between different processing regions 21 is performed by the mounting table 350.

[0173] In addition, in the laser processing method of the present embodiment, pulsed lasers are simultaneously irradiated onto two of the plurality of processing regions 21. Therefore, according to the laser processing method of the present embodiment, the processing time can be further shortened.

[0174] In addition, the splitting optical system 380 may also split the laser beam from the mask 335 into three or more laser beams. In this case, for example, three galvanometric scanners are provided for each of the split laser beams. With such a configuration, pulsed laser beams can be simultaneously irradiated onto three or more of the plurality of processing regions 21. Additionally, it is preferable that the number of split laser beams is half or less of the number of processing regions 21, and the number of processing regions 21 is an integer multiple of the number of split laser beams.

[0175] Furthermore, the laser processing apparatus 300 may not include the galvanometric scanners 363 and 366. In this case, for example, the irradiation region 22 within the processing region 21 is moved in the X direction by the stage 350.

[0176] As described above, the present invention has been described by way of embodiments, but the above embodiments can be appropriately modified. For example, the shape of the laser beam irradiated onto the workpiece 20 is a rectangle elongated in the Y direction, but it may be a shape other than a rectangle, such as a circular shape.

[0177] Moreover, the laser processing apparatus 300 may not include the fθ lenses 370 and 371.

[0178] The above description is illustrative rather than restrictive. Therefore, it will be apparent to those skilled in the art that the embodiments of the present disclosure can be modified without departing from the claims. In addition, it will be apparent to those skilled in the art to use combinations of the embodiments of the present disclosure. Unless otherwise specified, the terms used in this specification and the claims should be construed as "non-limiting". For example, terms such as "comprising", "having", "including", and "possessing" should be construed as "not excluding the presence of elements other than those described". Additionally, the modifier "one" should be construed as meaning "at least one" or "one or more". Furthermore, the phrase "at least one of A, B, and C" should be construed as "A", "B", "C", "A + B", "A + C", "B + C", or "A + B + C", and should also be construed as including combinations with elements other than "A", "B", and "C".

Claims

1. A laser processing system for forming a plurality of recessed portions by irradiating a plurality of processing areas separated from each other in a first direction on a surface of a workpiece with a pulsed laser, wherein: The laser processing system comprises: a gas laser device that emits the pulse laser; a moving portion capable of moving an irradiation area of ​​the pulse laser on the surface in the first direction; and a first Galvano scanner capable of changing the optical path of the pulsed laser to move the irradiated area in the first direction, The moving unit moves the irradiation area so as to overlap with a portion of the irradiation area of ​​the immediately preceding pulse laser. The first Galvano scanner moves the irradiation area so as to be located within the processing area different from the processing area irradiated by the immediately preceding pulse laser.

2. The laser processing system according to claim 1, wherein: The moving portion is a mounting table 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 Galvano scanner that changes the optical path of the pulse laser along the first direction.

4. The laser processing system according to claim 3, wherein: The second Galvano scanner is located upstream of the first Galvano scanner in the traveling direction of the pulse laser.

5. The laser processing system according to claim 4, wherein: A minimum moving distance of the irradiation area that can be adjusted by the second Galvano scanner is shorter than a minimum moving distance of the irradiation area that can be adjusted by the first Galvano scanner.

6. The laser processing system according to claim 1, wherein: The laser processing system further includes a third Galvano scanner that changes an optical path of the pulsed laser so as to move the irradiation area in a second direction perpendicular to the first direction.

7. The laser processing system according to claim 6, wherein: A minimum moving distance of the irradiation area that can be adjusted by the moving unit is shorter than a minimum moving distance of the irradiation area that can be adjusted by the third Galvano scanner.

8. The laser processing system according to claim 1, wherein: The laser processing system further includes a splitting optical system for splitting the pulse laser into a plurality of parts. The first Galvano scanner is set for each of the divided pulse lasers.

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

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

11. The laser processing system according to claim 1, wherein: The laser processing system further includes an fθ lens that focuses the pulse laser light on the surface of the workpiece.

12. A laser processing method, comprising: irradiating a plurality of processing areas separated from each other in a first direction on a surface of a workpiece with a pulsed laser to form a plurality of recesses, wherein: The laser processing method comprises: A first step of moving the irradiation area of ​​the pulse laser on the surface in the first direction by a moving portion capable of moving the irradiation area of ​​the pulse laser on the surface so as to overlap with a portion of the irradiation area of ​​the immediately preceding pulse laser within the processing area irradiated by the immediately preceding pulse laser; as well as In the second step, the irradiation area is moved by a first Galvano scanner capable of changing the optical path of the pulse laser to move the irradiation area in the first direction so that it is located in the processing area different from the processing area irradiated by the pulse laser immediately before.

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