Laser processing apparatus, laser processing method, and method for manufacturing electronic device

Abstract

This laser machining apparatus irradiates an article being machined, in which a resin layer is arranged on a machining surface, with laser light outputted upon induction of discharge and excitation between a pair of discharge electrodes to form a hole in the article being machined, the laser machining apparatus comprising: a laser device that outputs laser light for which a first emission angle in the direction of discharge between the pair of discharge electrodes is greater than a second emission angle in a direction perpendicular to the discharge direction and to the direction in which the laser light advances; a transfer mask that forms a transfer pattern; a guidance optical system for guiding the laser light to the transfer mask; a projection optical system that causes the transfer pattern to be formed on the resin layer; and an emission-angle adjustment optical system arranged in the optical path of the laser light, the emission-angle adjustment optical system making an adjustment such that the difference between the first emission angle and the second emission angle decreases.

Description

[Technical Field]

[0001] The present disclosure relates to a laser processing apparatus, a laser processing method, and a method for manufacturing an electronic device. [Background technology]

[0002] In recent years, semiconductor exposure devices have been required to improve their resolution in response to the miniaturization and high integration of semiconductor integrated circuits. To this end, the wavelength of light emitted from exposure light sources has been shortened. For example, KrF excimer laser devices, which output laser light with a wavelength of approximately 248.0 nm, and ArF excimer laser devices, which output laser light with a wavelength of approximately 193.4 nm, are used as gas laser devices for exposure.

[0003] The spectral linewidth of the spontaneously oscillating light of KrF excimer laser devices and ArF excimer laser devices is as wide as 350 pm to 400 pm. Therefore, if a projection lens is constructed using a material that transmits ultraviolet light, such as KrF and ArF laser light, chromatic aberration may occur. As a result, resolution may decrease. Therefore, it is necessary to narrow the spectral linewidth of the laser light output from the gas laser device to a level where chromatic aberration is negligible. Therefore, a line narrowing module (LNM) including a line narrowing element (e.g., an etalon or a grating) may be installed in the laser resonator of the gas laser device to narrow the spectral linewidth. Hereinafter, a gas laser device with a narrowed spectral linewidth is referred to as a line narrowing gas laser device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-186185 [Patent Document 2] U.S. Patent No. 9,168,614 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-51990 [Patent Document 4] Summary of Japanese Patent Application Publication No. 10-314965

[0005] A laser processing apparatus according to one aspect of the present disclosure is a laser processing apparatus that forms a hole in a workpiece having a resin layer disposed on its processing surface by irradiating the workpiece with laser light output by discharge excitation between a pair of discharge electrodes, and that includes a laser device that outputs laser light in which a first divergence angle in the discharge direction between the pair of discharge electrodes is greater than a second divergence angle in a direction perpendicular to the discharge direction and the direction of travel of the laser light, a transfer mask that forms a transfer pattern, an introduction optical system for guiding the laser light to the transfer mask, a projection optical system that images the transfer pattern on the resin layer, and a divergence angle adjustment optical system that is arranged in the optical path of the laser light and adjusts the difference between the first divergence angle and the second divergence angle to be small.

[0006] A laser processing method according to one aspect of the present disclosure is a laser processing method for forming a hole in a workpiece having a resin layer disposed on its processing surface by irradiating the workpiece with laser light output by discharge excitation between a pair of discharge electrodes, the method comprising: a workpiece setting step for setting the workpiece having the resin layer disposed on a table of a movable stage; a transfer positioning step for relatively positioning the workpiece and the transfer position so that the transfer position coincides with the surface of the resin layer; a laser output step for outputting laser light to the workpiece having the resin layer disposed on it, the laser light having a first divergence angle in the discharge direction between the pair of discharge electrodes that is greater than a second divergence angle in a direction perpendicular to the discharge direction and the traveling direction of the laser light; an optical introduction step for guiding the laser light to a transfer mask; a transfer pattern formation step for forming a transfer pattern; a transfer imaging step for imaging the transfer pattern on the resin layer; and a divergence angle adjustment step for adjusting the difference between the first divergence angle and the second divergence angle to be smaller.

[0007] A method for manufacturing an electronic device according to one aspect of the present disclosure includes a first bonding step of bonding an interposer and an integrated circuit chip to electrically connect them to each other, and a second bonding step of bonding the interposer and a circuit board to electrically connect them to each other, wherein the interposer includes an insulating substrate having a plurality of through holes formed therein and a conductor provided in the plurality of through holes, and the plurality of through holes are formed by a laser processing method that forms holes at each irradiation position of a plurality of laser beams irradiated onto an insulating substrate having a resin layer disposed on a processing surface, and the laser processing method includes generating laser beams having a first divergence angle in a discharge direction between a pair of discharge electrodes that is larger than a second divergence angle in a direction perpendicular to the discharge direction and the traveling direction of the laser beam, reducing the difference between the first divergence angle and the second divergence angle of the laser beam, and then focusing the laser beam on the resin layer to form through holes in the insulating substrate. [Brief explanation of the drawings]

[0008] Some embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 shows a schematic configuration of a laser processing device according to a comparative example. [Figure 2] FIG. 2 is a flowchart showing the laser processing procedure. [Figure 3] FIG. 3 is a flowchart showing the procedure of the laser processing. [Figure 4] FIG. 4 shows the beam shape of the laser light irradiated onto the transfer mask. [Figure 5] FIG. 5 shows an example of the first divergence angle and the second divergence angle of the laser light irradiated onto the transfer mask. [Figure 6] FIG. 6 shows an example of a method for measuring the divergence angle of laser light. [Figure 7] FIG. 7 shows the relationship between the beam shape of the laser light that passes through the transfer mask and enters the projection optical system and the effective projection area. [Figure 8] FIG. 8 is a photograph showing a state in which a bulge occurs around a processed hole due to drilling using the laser processing device according to the comparative example. [Figure 9]FIG. 9 is a photograph showing the state in which cracks are generated by drilling using the laser processing device according to the comparative example. [Figure 10] FIG. 10 shows an example in which a through hole is formed in a workpiece having a resin film disposed on the surface thereof using a laser processing device according to a comparative example. [Figure 11] FIG. 11 is a graph showing the relationship between the fluence and the beam diameter in the drilling process shown in FIG. [Figure 12] FIG. 12 is a photograph showing the results of drilling a workpiece on which a resin film is placed, using a laser processing device according to a comparative example. [Figure 13] FIG. 13 shows the results of drilling a workpiece on which no resin film is placed and the results of drilling a workpiece on which a resin film is placed. [Figure 14] FIG. 14 shows a schematic configuration of the laser processing apparatus of the first embodiment. [Figure 15] FIG. 15 is a diagram showing the configuration of the NA adjustment aperture. [Figure 16] FIG. 16 shows the relationship between the beam shape of the laser light that passes through the transfer mask and enters the NA adjustment aperture and the effective projection area. [Figure 17] FIG. 17 is a flowchart showing the laser processing procedure of the first embodiment. [Figure 18] FIG. 18 shows an outline of laser processing of a workpiece on which a resin film is placed, using the laser processing device according to the first embodiment. [Figure 19] FIG. 19 shows the relationship between the first divergence angle and the second divergence angle of the laser light after passing through the NA adjustment aperture. [Figure 20] FIG. 20 is a graph showing the swelling suppression effect when processing a workpiece on which a resin film is arranged using the laser processing device according to the first embodiment. [Figure 21] FIG. 21 is a graph showing that cracks are suppressed when a workpiece on which a resin film is placed is processed by the laser processing device according to the first embodiment. [Figure 22]FIG. 22 is a photograph showing the result of laser processing of a glass substrate on which a resin film is arranged, using the laser processing device according to the first embodiment. [Figure 23] FIG. 23 is a photograph showing the results of improving the shape of the processed hole. [Figure 24] FIG. 24 is a diagram showing a first modified example of the NA adjustment aperture. [Figure 25] FIG. 25 is a diagram showing a second modified example of the NA adjustment aperture. [Figure 26] FIG. 26 schematically shows the configuration of a laser processing apparatus according to the second embodiment. [Figure 27] FIG. 27 shows the configuration of a beam width expanding type beam expander. [Figure 28] FIG. 28 shows the configuration of a beam width reduction type beam expander. [Figure 29] FIG. 29 shows the configuration of a beam width expanding type beam expander. [Figure 30] FIG. 30 shows the configuration of a beam width reduction type beam expander. [Figure 31] FIG. 31 shows an outline of the operation of performing laser processing using a beam width expanding type beam expander. [Figure 32] FIG. 32 is a diagram showing the shape of a beam irradiated onto a transfer mask. [Figure 33] FIG. 33 shows the difference in NA of the beam shape irradiated to the beam expander. [Figure 34] FIG. 34 is a diagram showing the shape of a beam irradiated onto a transfer mask. [Figure 35] FIG. 35 shows an outline of the operation of performing laser processing using a beam width reduction type beam expander. [Figure 36] FIG. 36 is a diagram showing the shape of a beam irradiated onto a transfer mask. [Figure 37] FIG. 37 shows a schematic configuration of a laser processing device according to a modified example. [Figure 38] FIG. 38 is a perspective view showing a first configuration example of the fly-eye lens. [Figure 39]FIG. 39 is a perspective view showing a second configuration example of the fly-eye lens. [Figure 40] FIG. 40 is a schematic diagram showing how the fly-eye lens is irradiated with laser light L whose beam width in the Y direction has been expanded to B2 by a beam expander. [Figure 41] FIG. 41 is a schematic diagram showing how the effective area of ​​the projection optical system is irradiated with laser light L that has passed through a multipoint transfer mask. [Figure 42] FIG. 42 is a schematic diagram showing an example of the schematic configuration of an electronic device. [Figure 43] FIG. 43 is a flowchart showing a method for manufacturing an electronic device. Embodiment

[0009] <Contents> 1. Comparative Example 1.1 Configuration 1.2 Operation 1.3 Challenges 2. First embodiment 2.1 Configuration 2.2 Operation 2.3 Actions and Effects 2.4 Modified NA adjustment aperture 3. Second embodiment 3.1 Configuration 3.2 Operation 3.3 Actions and Effects 4. Modified examples of laser processing equipment 4.1 Configuration 4.2 Operation 4.3 Actions and Effects 5. Method for manufacturing an electronic device using the laser processing apparatus according to the present disclosure

[0010] 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. Furthermore, not all of the configurations and operations described in each embodiment are necessarily essential as the configurations and operations of the present disclosure. Note that the same components are given the same reference symbols, and redundant explanations will be omitted.

[0011] 1. Comparative Example 1.1 Configuration 1 shows a schematic configuration of a laser processing apparatus 2 according to a comparative example. Note that the comparative example is a configuration that the applicant recognizes as being known only by the applicant, and is not a publicly known example that the applicant acknowledges.

[0012] The laser processing apparatus 2 mainly comprises a laser device 3, an optical path pipe 5, and a laser processing apparatus main body 4. The laser device 3 and the laser processing apparatus main body 4 are connected by the optical path pipe 5. In the following description, the direction parallel to the optical axis direction of the laser light incident on the workpiece 41 is referred to as the X direction, the direction perpendicular to the X direction is referred to as the Z direction, and the direction perpendicular to the X and Z directions is referred to as the Y direction. The X direction corresponds to the height direction of the workpiece 41.

[0013] The laser device 3 mainly comprises a housing 301, a laser oscillator 10 arranged in the internal space of the housing 301, a monitor module 11, a shutter 12, and a laser processor 13. The laser device 3 is an ArF excimer laser device that uses a mixed gas containing argon (Ar), fluorine (F2), and neon (Ne) as a laser medium. The laser device 3 emits laser light with a center wavelength of approximately 193.4 nm.

[0014] The laser device 3 may be a laser device other than an ArF excimer laser device, such as a KrF excimer laser device that uses a mixed gas containing krypton (Kr), F2, and Ne. In this case, the laser device 3 emits laser light with a center wavelength of approximately 248.0 nm. The mixed gas containing Ar, F2, and Ne as the laser medium and the mixed gas containing Kr, F2, and Ne as the laser medium will hereinafter be referred to as laser gas.

[0015] The laser oscillator 10 includes a laser chamber 21, a charger 23, a pulse power module (PPM) 24, a rear mirror 26, and an output coupling mirror 27. Fig. 1 shows the internal configuration of the laser chamber 21 as viewed from a direction substantially perpendicular to the traveling direction of the laser light.

[0016] Laser chamber 21 includes an internal space where light is generated by excitation of a laser medium in laser gas. The laser gas is supplied to the internal space of laser chamber 21 from a laser gas supply source (not shown) through piping (not shown). The light generated by excitation of the laser medium travels to windows 21a and 21b (described below).

[0017] A pair of electrodes 22a, 22b are arranged in the internal space of the laser chamber 21, facing each other, with their longitudinal directions aligned with the direction of travel of the light. The pair of electrodes 22a, 22b are discharge electrodes for exciting the laser medium by glow discharge. In this example, the electrode 22a is a cathode, and the electrode 22b is an anode.

[0018] The electrode 22a is supported by an electrical insulator 28. An opening is formed in the laser chamber 21, and this opening is closed by the electrical insulator 28. A conductive portion is embedded in the electrical insulator 28. The conductive portion applies a high voltage supplied from the pulse power module 24 to the electrode 22a. The electrode 22b is supported by a return plate 21d. This return plate 21d is connected to the inner surface of the laser chamber 21 by wiring (not shown).

[0019] The charger 23 is a DC power supply device that charges a charging capacitor (not shown) in the pulse power module 24 with a predetermined voltage. The pulse power module 24 includes a switch 24a that is controlled by the laser processor 13. When the switch 24a is turned from OFF to ON, the pulse power module 24 generates a pulsed high voltage from the electrical energy held in the charger 23 and applies it between the pair of electrodes 22a, 22b.

[0020] When a high voltage is applied between electrodes 22a and 22b, a discharge occurs between electrodes 22a and 22b. The energy of this discharge excites the laser medium in laser chamber 21. When the excited laser medium transitions to its ground state, it emits laser light. The discharge surfaces of the pair of electrodes 22a and 22b are rectangular. Electrodes 22a and 22b are arranged so that the discharge surface of electrode 22a and the discharge surface of electrode 22b face each other in the X direction.

[0021] Windows 21a and 21b are provided on both ends of the laser chamber 21. The window 21a is located at one end in the traveling direction of the laser light, and the window 21b is located at the other end. As will be described later, the oscillated laser light is emitted to the outside of the laser chamber 21 through the windows 21a and 21b. The laser light is generated by applying a pulsed high voltage between the electrodes 22a and 22b by the pulse power module 24, and is therefore a pulsed laser light.

[0022] The rear mirror 26 is disposed in the internal space of a housing 26a connected to one end side of the laser chamber 21, and reflects the light emitted from the window 21a of the laser chamber 21 with high reflectivity and returns it to the laser chamber 21. The output coupling mirror 27 is disposed in the internal space of an optical path pipe 147a connected to the other end side of the laser chamber 21, and transmits and outputs a portion of the light output from the window 21b of the laser chamber 21, and reflects the other portion back into the laser chamber 21.

[0023] The rear mirror 26 and the output coupling mirror 27 form a Fabry-Perot type laser resonator, and the laser chamber 21 is disposed on the optical path of the laser resonator. The light emitted from the laser chamber 21 travels back and forth between the rear mirror 26 and the output coupling mirror 27, and is amplified each time it passes through the laser gain space between the electrodes 22a and 22b. A portion of the amplified light is output as laser light via the output coupling mirror 27.

[0024] The monitor module 11 is disposed on the optical path of the laser light emitted from the output coupling mirror 27. The monitor module 11 includes a housing 11c, a beam splitter 11a, and an optical sensor 11b. An opening is formed in the housing 11c, and the internal space of the housing 11c communicates with the internal space of the optical path pipe 27a through this opening. The beam splitter 11a and the optical sensor 11b are disposed in the internal space of the housing 11c.

[0025] The beam splitter 11a transmits the laser light emitted from the output coupling mirror 27 toward the shutter 12 with high transmittance, and also reflects a portion of the laser light toward the light-receiving surface of the optical sensor 11b. The optical sensor 11b measures the pulse energy E of the laser light incident on the light-receiving surface. The optical sensor 11b is electrically connected to the laser processor 13, and outputs data of the measured pulse energy E to the laser processor 13.

[0026] The laser processor 13 of the present disclosure is a processing device including a storage device (not shown) storing a control program and a CPU (Central Processing Unit) that executes the control program. The laser processor 13 also controls the entire laser device 3.

[0027] The laser processor 13 receives data on the pulse energy E from the optical sensor 11b of the monitor module 11. The laser processor 13 also transmits and receives various signals to and from the laser processing processor 32. For example, the laser processor 13 receives data on the light emission trigger Tr and the target pulse energy Et from the laser processing processor 32. The laser processor 13 also transmits a setting signal for the charging voltage to the charger 23, and transmits a command signal to the pulse power module 24 to turn the switch 24a on or off.

[0028] The laser processor 13 receives data on the pulse energy E from the monitor module 11 and controls the charging voltage of the charger 23 by referring to the received data. The laser processor 13 controls the charging voltage of the charger 23, thereby controlling the energy of the laser light.

[0029] The shutter 12 is disposed in the internal space of the optical path pipe 12a connected to the housing 11c of the monitor module 11, on the optical path of the laser light transmitted through the beam splitter 11a. The optical path pipe 12a is connected to the side of the housing 11c opposite to the side to which the optical path pipe 27a is connected. The internal space of the optical path pipe 12a communicates with the internal space of the housing 11c via an opening formed in the housing 11c. Furthermore, the optical path pipe 12a communicates with the optical path pipe 5 via an opening formed in the housing 301.

[0030] The shutter 12 is electrically connected to the laser processor 13. After the start of laser oscillation, the laser processor 13 controls the shutter 12 to close until the difference between the pulse energy E received from the monitor module 11 and the target pulse energy Et falls within an allowable range. The laser processor 13 controls the shutter 12 to open when the difference between the pulse energy E received from the monitor module 11 and the target pulse energy Et falls within an allowable range. The laser processor 13 transmits a signal indicating that a laser light emission trigger Tr is ready to be received to the laser processing processor 32 of the laser processing device main body 4 in synchronization with the opening / closing signal of the shutter 12. The emission trigger Tr is defined by a predetermined repetition frequency f of the laser light and a predetermined pulse number P, and is a timing signal that the laser processing processor 32 causes the laser oscillator 10 to oscillate. The repetition frequency f of the laser light is, for example, within a range of 1 kHz to 10 kHz.

[0031] The internal spaces of the optical path pipes 12a and 27a and the internal spaces of the housings 11c and 26a are filled with a purge gas. The purge gas contains an inert gas such as high-purity nitrogen. The purge gas is supplied from a purge gas supply source (not shown) through piping (not shown) to the internal spaces of the optical path pipes 12a and 27a and the internal spaces of the housings 11c and 26a.

[0032] An exhaust device (not shown) is disposed in the internal space of the laser device 3 to exhaust the laser gas from the internal space of the laser chamber 21. The exhaust device performs processing such as removing F2 gas using a halogen filter on the gas exhausted from the internal space of the laser chamber 21, and releases the gas into the housing 301 of the laser device 3.

[0033] The laser light passes through shutter 12 while shutter 12 is open and is output from optical path pipe 12a of laser device 3. Hereinafter, the laser light output from laser device 3 will be referred to as laser light L.

[0034] The laser processing device main body 4 includes a laser processing processor 32, a table 33, a moving stage 34, an optical device 36, a housing 37, and a frame 38. The optical device 36 is disposed within the housing 37. The housing 37 and the moving stage 34 are fixed to the frame 38.

[0035] Table 33 supports workpiece 41. Workpiece 41 is an object to be laser processed by being irradiated with laser light L. Workpiece 41 is made of a material that is transparent to ultraviolet laser light L, such as synthetic quartz glass. In this comparative example, the laser processing is a drilling process that drills holes in workpiece 41.

[0036] The moving stage 34 supports the table 33. The moving stage 34 is movable in the X, Y, and Z directions, and the position of the workpiece 41 can be adjusted by adjusting the position of the table 33. Under the control of the laser processing processor 32, the moving stage 34 adjusts the position of the workpiece 41 so that the laser light L emitted from the optical device 36 is irradiated onto a desired processing position.

[0037] The laser processing device 2, for example, drills holes at one or more positions on the workpiece 41. Position data representing processing positions is sequentially set in the laser processing processor 32. The position data is, for example, coordinate data that defines the positions of each processing position in the X, Y, and Z directions relative to the origin position of the moving stage 34. The laser processing processor 32 controls the amount of movement of the moving stage 34 based on the coordinate data, and positions the workpiece 41 on the moving stage 34.

[0038] The optical device 36 includes, for example, high-reflection mirrors 36a and 36b, an attenuator 52, an introduction optical system 46, a transfer mask 47, and a projection optical system 48, and transfers an image corresponding to the processing shape onto the surface of the workpiece 41. The high-reflection mirrors 36a and 36b, the introduction optical system 46, the transfer mask 47, and the projection optical system 48 are each fixed to a holder (not shown), and are arranged at a predetermined position within the housing 37.

[0039] The high-reflection mirrors 36a and 36b reflect the laser light L in the ultraviolet region with high reflectance. The high-reflection mirror 36a reflects the laser light L input from the laser device 3 toward the high-reflection mirror 36b. The high-reflection mirror 36b reflects the laser light L toward the introduction optical system 46.

[0040] The introduction optical system 46 includes a high-reflection mirror 46a, and is arranged to homogenize the light intensity distribution of the laser light L reflected by the high-reflection mirror 46b and to Kohler-illuminate the transfer mask 47 with the rectangular beam-shaped laser light L. The high-reflection mirror 46a is a transparent substrate made of, for example, synthetic quartz or calcium fluoride, and its surface is coated with a reflective film that highly reflects the laser light L.

[0041] The transfer mask 47 is disposed on the optical path between the introduction optical system 46 and the projection optical system 48. The transfer mask 47 transmits a portion of the laser light L emitted from the introduction optical system 46, thereby forming an image corresponding to the processing shape of the workpiece 41. The transfer mask 47 is, for example, a light-shielding plate having a light-shielding property for blocking the laser light L, and has transmission holes formed therein that correspond to the shape of the transfer pattern. In this example, the transfer pattern is a circular pattern, and the transmission holes are circular pinholes 47a.

[0042] By using such a transfer mask 47, the laser processing device body 4 of this example performs a drilling process on the workpiece 41 to form a hole having a circular cross section.

[0043] The projection optical system 48 collects the incident laser light L and emits it towards the workpiece 41 through the window 42. The projection optical system 48 constitutes a transfer optical system that focuses a transfer image, which is generated by the laser light L passing through the transfer mask 47, at a position according to the focal length of the projection optical system 48. Hereinafter, the imaging position where the transfer image is formed by the action of the projection optical system 48 will be referred to as the transfer position.

[0044] This transfer position is set at a position in the X direction that coincides with the surface on the incident side onto which the laser light L is incident. Hereinafter, when simply referring to the surface of the workpiece 41, it means the surface on the incident side of the workpiece 41.

[0045] The projection optical system 48 is configured by, for example, a combination of multiple lenses. The projection optical system 48 is a reduction optical system that forms a transfer image at the transfer position that is smaller than the actual dimensions of the pinhole 47a formed in the transfer mask 47. The magnification M of the transfer optical system configured by the projection optical system 48 is, for example, 1 / 10 to 1 / 5. The projection optical system 48 may also be configured by a single lens.

[0046] The window 42 is disposed on the optical path between the projection optical system 48 and the workpiece 41, and is fixed in an opening formed in the housing 37 and sealed with an O-ring (not shown).

[0047] The attenuator 52 is disposed in the housing 37 on the optical path between the high-reflection mirror 36a and the high-reflection mirror 36b. The attenuator 52 includes, for example, two partial reflection mirrors 52a and 52b and rotation stages 52c and 52d for these partial reflection mirrors. The two partial reflection mirrors 52a and 52b are optical elements whose transmittance changes depending on the angle of incidence of the laser light L. The tilt angles of the partial reflection mirrors 52a and 52b are adjusted by the rotation stages 52c and 52d so that the angles of incidence of the laser light L match each other and the desired transmittance is achieved.

[0048] As a result, the laser light L is attenuated to the desired energy and passes through the attenuator 52. The transmittance T of the attenuator 52 is controlled based on a control signal from the laser processing processor 32. The laser processing processor 32 controls the fluence of the laser light L by controlling the transmittance T of the attenuator 52, in addition to controlling the fluence of the laser light L output by the laser device 3 through the target pulse energy Et.

[0049] Nitrogen (N2) gas, which is an inert gas, constantly flows inside the housing 37 while the laser processing apparatus 2 is in operation. The housing 37 is provided with an intake port 37a that draws nitrogen gas into the housing 37 and an exhaust port 37b that exhausts nitrogen gas from the housing 37 to the outside. An intake pipe and an exhaust pipe (not shown) can be connected to the intake port 37a and the exhaust port 37b. A nitrogen gas supply source 43 is connected to the intake port 37a.

[0050] 1.2 Operation The operation of the laser processing device 2 will be described with reference to FIGS.

[0051] 2, when laser processing is performed, the workpiece 41 is set on the table 33 of the moving stage 34 (S100). The laser processing processor 32 sets position data of the initial processing position in the moving stage 34 (S110).

[0052] The laser processing processor 32 controls the moving stage 34 to adjust the position of the workpiece 41 in the YZ plane (S120). In S120, the laser processing processor 32 adjusts the position of the workpiece 41 in the YZ plane by controlling the amount of movement of the moving stage 34 based on the coordinate data in the YZ plane included in the position data. This allows the position of the workpiece 41 in the YZ plane to be determined.

[0053] Next, the laser processing processor 32 controls the moving stage 34 to adjust the position of the workpiece 41 in the X direction so that the transfer position of the transferred image of the laser light L coincides with the surface of the workpiece 41 (S130). Specifically, in the position data, the position of the workpiece 41 in the X direction is specified so that the transfer position of the transferred image of the laser light L coincides with the surface of the workpiece 41. The transfer position of the transferred image is determined by the distance between the transfer mask 47 and the projection optical system 48, the focal length of the projection optical system 48, etc.

[0054] In S130, the laser processing processor 32 adjusts the position of the workpiece 41 in the X direction by controlling the amount of movement of the moving stage 34 based on the position data. As a result, the transfer position and the workpiece 41 are positioned relative to each other in the X direction so that the transfer position and the surface of the workpiece 41 coincide with each other. Since the X direction is parallel to the optical axis direction of the laser light L incident on the workpiece 41, positioning in the X direction corresponds to positioning in the optical axis direction of the laser light L.

[0055] After the positioning of the workpiece 41 is completed, laser processing is performed (S140).

[0056] Laser processing is performed according to the flowchart shown in Fig. 3. The laser processing processor 32 controls the energy of the laser light L on the surface of the workpiece 41, which is the transfer position of the transfer image, so that it reaches a target fluence Ft. Specifically, the laser processing processor 32 controls the energy incident on the workpiece 41 by controlling the target pulse energy Et and the transmittance T of the attenuator 52. The laser processing processor 32 also transmits the target pulse energy Et to the laser processor 13 of the laser device 3. As a result, the target pulse energy Et is set in the laser processor 13 (S141).

[0057] Here, the target fluence Ft is the fluence required for laser processing, and is the energy density of the laser light L at the transfer position of the transferred image of the laser light L. When the optical loss of the optical device 36 can be ignored, the target fluence Ft is defined by the following formula (1). Ft=M -2 (T·Et) / S IL [mJ / cm 2 ] ···(1) where S IL is the beam area of ​​the laser light L that is Koehler illuminated onto the transfer mask 47.

[0058] Of the laser light L irradiated onto the transfer mask 47, only the component that passes through the pinhole 47a, which is the transfer pattern, is irradiated onto the workpiece 41 and contributes to the fluence. When the projection optical system 48 is a reduction optical system as in this example, the smaller the value of the magnification M, i.e., the more the image is reduced, the greater the fluence becomes.

[0059] When the laser processor 13 receives the target pulse energy Et from the laser processing processor 32, it closes the shutter 12 and activates the charger 23. Then, the laser processor 13 turns on the switch 24a of the pulse power module 24 using an internal trigger (not shown), which causes the laser oscillator 10 to oscillate.

[0060] The monitor module 11 samples the laser light L output from the laser oscillator 10 and measures the pulse energy E, which is the actual measured value of the energy. The laser processor 13 controls the charging voltage of the charger 23 so that the difference ΔE between the pulse energy E and the target pulse energy Et approaches 0. Specifically, the laser processor 13 controls the charging voltage so that the difference ΔE falls within an allowable range (S142).

[0061] The laser processor 13 monitors whether the difference ΔE is within the allowable range (S142). When the difference ΔE is within the allowable range (Y in S142), the laser processor 13 transmits a reception preparation completion signal to the laser processing processor 32 to notify that preparation for receiving the light emission trigger Tr is complete, and opens the shutter 12. This causes the laser device 3 to enter a state where preparation for receiving the light emission trigger Tr is complete (S143).

[0062] When the laser processing processor 32 receives the ready-to-receive signal, it sets the transmittance T of the attenuator 52 so that the fluence of the laser light L at the transfer position of the transferred image becomes the target fluence Ft (S144).

[0063] When there is no optical loss in the optical device 36, the transmittance T of the attenuator 52 can be calculated from the above equation (1) as shown in the following equation (2). T=(Ft / Et)S IL M 2 ···(2)

[0064] After setting the transmittance T of the attenuator 52, the laser processing processor 32 transmits a light emission trigger Tr, which is defined by a predetermined repetition frequency f and a predetermined number of pulses N, to the laser processor 13 (S145). As a result, in synchronization with the light emission trigger Tr, the laser light L that has passed through the beam splitter 11a of the monitor module 11 is output from the laser device 3 and enters the laser processing device main body 4.

[0065] The laser light L incident on the laser processing device main body 4 passes through the high-reflection mirror 36a and is attenuated by the attenuator 52. The laser light L transmitted through the attenuator 52 is reflected by the high-reflection mirror 36b and enters the introduction optical system 46. The light intensity of the laser light L is spatially uniformed in the introduction optical system 46, and the laser light L illuminates the transfer mask 47 with a rectangular beam shape by Koehler illumination.

[0066] Of the laser light L irradiated onto the transfer mask 47, the laser light L that has passed through the pinhole 47a enters the projection optical system 48. The projection optical system 48 transfers a reduced transfer image onto the surface of the workpiece 41 through the window 42. This laser irradiation of the laser light L is performed in accordance with a light emission trigger Tr that is defined by the repetition frequency f and the number of pulses N required for laser processing (S145). This laser irradiation forms a circular hole in the workpiece 41.

[0067] 1.3 Challenges Circuit boards, which are widely used in various electronic devices, are required to have finer and denser circuit wiring in order to reduce the size and improve the functionality of the electronic devices. Furthermore, finer and denser circuit wiring is also required to realize high-quality circuit boards. To achieve finer and denser circuit wiring, for example, when forming holes that penetrate insulating layers connecting conductor layers in a circuit board, a drilling technique is required that can suppress swelling and cracking around the holes. Hereinafter, a hole that penetrates a workpiece 41 is referred to as a through hole.

[0068] The laser light L output from the laser device 3 is not a parallel beam, but a divergent light that diverges with an expansion. The divergence angle differs between the X direction, which is the discharge direction, and the Y direction, which is the direction perpendicular to the discharge direction. The difference in the divergence angle depends on the aspect ratio of the rectangular discharge space as viewed from the Z direction. In the laser device 3, the distance between electrodes 22a and 22b is longer than the width of electrodes 22a and 22b, so the discharge space is longer in the X direction than in the Y direction. Therefore, the divergence angle of the laser light L output from the laser device 3 in the X direction is larger than the divergence angle in the Y direction. Hereinafter, the divergence angle in the X direction will be referred to as the first divergence angle θ1, and the divergence angle in the Y direction will be referred to as the second divergence angle θ2.

[0069] Fig. 4 shows an example of the beam shape of the laser light L irradiated onto the transfer mask 47. Fig. 5 shows an example of the first divergence angle θ1 and the second divergence angle θ2 of the laser light L irradiated onto the transfer mask 47.

[0070] In the laser processing device 2, the laser light L reflected by the high-reflection mirror 36b is reflected by the high-reflection mirror 46c of the introduction optical system 46 and is incident on the transfer mask 47 in a rectangular beam shape (B1 × B2) as shown in Fig. 4. The laser light L irradiated onto the transfer mask 47 travels while maintaining the difference between the first divergence angle θ1 and the second divergence angle θ2, as shown in Fig. 5.

[0071] In the transfer mask 47, the first divergence angle θ1 corresponds to the divergence angle in the Z direction, and the second divergence angle θ2 corresponds to the divergence angle in the Y direction. Hereinafter, the difference between the first divergence angle θ1 and the second divergence angle θ2 will be referred to as the NA (Numerical Aperture) difference.

[0072] Fig. 6 shows an example of a method for measuring the divergence angle of laser light L. For example, as shown in Fig. 6, laser light L output from laser device 3 is imaged on two-dimensional image sensor 17 via lens 18. The size of the image of laser light L imaged on two-dimensional image sensor 17 is measured and divided by the distance d between lens 18 and two-dimensional image sensor 17, thereby measuring the first divergence angle θ1 and the second divergence angle θ2.

[0073] 7 shows the relationship between the beam shape of the laser light L that passes through the transfer mask 47 and enters the projection optical system 48 and the effective area 48A of the projection optical system 48. The laser light L that passes through the transfer mask 47 forms an irradiation pattern, but as shown in FIG. 7, it enters the projection optical system 48 while maintaining the NA difference. The laser light L that passes through the projection optical system 48 is then irradiated onto the surface of the workpiece 41 while maintaining the NA difference. In other words, when viewed from the workpiece 41, the laser light L having the NA difference is irradiated onto the surface, and ablation occurs, forming a fine hole. Hereinafter, the hole formed in the workpiece 41 will be referred to as a processed hole.

[0074] The present applicant has found that drilling with laser light L having an NA difference causes a problem in that swelling and cracks occur around the hole in the workpiece 41. FIG. 8 is a scanning electron microscope (SEM) photograph showing swelling around the hole caused by drilling with a laser processing device 2 according to a comparative example. As shown in FIG. 8, when drilling a hole in the workpiece 41 with laser light L having an NA difference, the periphery of the hole becomes covered with processing residue, causing swelling. FIG. 9 is an SEM photograph showing cracks caused by drilling with the laser processing device 2 according to a comparative example. As shown in FIG. 9, when drilling a hole in the workpiece 41 with laser light L having an NA difference, cracks occur around the hole.

[0075] To solve the above problems, it is conceivable to place a resin film 40 as a protective material on the surface of a workpiece 41. FIG. 10 shows an example of forming a through hole in a workpiece 41 having a resin film 40 placed on its surface using a laser processing device 2 according to a comparative example. As shown in FIG. 10, the resin film 40 was placed on the surface of the workpiece 41, and drilling was performed. Specifically, in order to suppress the occurrence of cracks, the fluence and beam diameter were adjusted at the position where the transfer position FP of the transferred image of the laser light L coincides with the surface 40a of the resin film 40, and drilling was performed. However, the problems of swelling and cracks were not improved.

[0076] Fig. 11 is a graph showing the relationship between the fluence and the beam diameter in the drilling process shown in Fig. 10. As shown in Fig. 11, when the beam diameter is 20.9 µm and the fluence is 23 J / cm 2 When the beam diameter was 16.7 μm and the fluence was 30 J / cm or more, the processed hole penetrated through to form a through hole, but cracks occurred. 2 When the beam diameter was 14.6 μm and the fluence was 42 J / cm or more, a through hole was formed, but cracks occurred. 2 When the beam diameter was 12.5 μm and the fluence was 55 J / cm or more, a through hole was formed, but cracks occurred. 2 When the beam diameter was 12.5 μm and the fluence was 39 J / cm or more, a through hole was formed, but cracks occurred. 2 When the beam diameter was 12.5 μm and the fluence was 47 J / cm or less, no cracks occurred, but the drilled hole did not penetrate through, and no through-hole was formed. 2 When the beam diameter was 10.4 μm and the fluence was 52 J / cm, cracks occurred and no through holes were formed. 2 When the temperature was below 100°C, no cracks occurred, but no through holes were formed.

[0077] Thus, in drilling to form through holes in a workpiece 41, placing a resin film 40 on the surface of the workpiece 41 did not solve the problem of cracking. Rather, a new problem arose. That is, at high fluence, an undesirable phenomenon occurred in which the shape of the drilled hole was distorted in a certain direction and became approximately elliptical, as shown in FIG. 12. FIG. 12 is an SEM photograph showing the results of drilling a workpiece 41 on which a resin film 40 was placed, using a laser processing device 2 according to a comparative example.

[0078] FIG. 13 shows the results of drilling a workpiece 41 on which no resin film 40 is placed, and the results of drilling a workpiece 41 on which a resin film 40 is placed. In the case of the workpiece 41 on which no resin film 40 is placed, swelling and cracking occurred regardless of the fluence. In the case of the workpiece 41 on which the resin film 40 is placed, swelling and cracking occurred regardless of the fluence. 2 At a low fluence of 36 J / cm, cracking was slightly improved, but no through holes were formed. 2 At a high fluence of 0.1, through holes were formed, but swelling and cracking could not be suppressed.

[0079] As described above, in the laser processing device 2 according to the comparative example, it was not possible to suppress swelling and cracking around the processed hole in the workpiece 41 by adjusting the fluence or beam diameter.

[0080] Therefore, in the following embodiments, a laser processing device and a laser processing method that can suppress swelling and cracking around a processed hole in a workpiece 41 will be disclosed.

[0081] 2. First embodiment Next, a description will be given of a laser processing apparatus and a laser processing method according to the first embodiment. Note that the same components as those described above are given the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0082] 2.1 Configuration Fig. 14 shows a schematic configuration of a laser processing apparatus 2A according to the first embodiment. The laser processing apparatus 2A according to the first embodiment includes a laser processing apparatus main body 4A instead of the laser processing apparatus main body 4 of the laser processing apparatus 2 according to the comparative example described with reference to Fig. 1.

[0083] Unlike the laser processing device body 4 of the comparative example, the laser processing device body 4A of the first embodiment includes an NA adjustment aperture 49. The other configurations of the laser processing device body 4A are similar to those of the laser processing device body 4 of the comparative example. The NA adjustment aperture 49 is an example of the "divergence angle adjustment optical system" according to the technique of the present disclosure.

[0084] The NA adjustment aperture 49 is disposed on the optical path of the laser light L between the transfer mask 47 and the projection optical system 48. The arrangement of the NA adjustment aperture 49 is not limited to that in this example. The NA adjustment aperture 49 may be disposed on the optical path of the laser light L between the transfer mask 47 and the workpiece 41.

[0085] Fig. 15 shows an example of the configuration of the NA adjustment aperture 49. As shown in Fig. 15, the NA adjustment aperture 49 has an aperture hole 49a formed therein to reduce the NA difference of the laser light L. The aperture hole 49a is formed within an effective projection area 49b onto which the laser light L transmitted through the transfer mask 47 is projected. In this embodiment, the aperture hole 49a has a circular shape. The aperture hole 49a is an example of an "aperture" according to the technology of the present disclosure.

[0086] The introduction optical system 46 and the transfer mask 47 are arranged so that the laser light L is irradiated onto the aperture 49a. Fig. 16 shows the relationship between the beam shape of the laser light L that passes through the transfer mask 47 and enters the NA adjustment aperture 49 and the effective projection area 49b. The transfer mask 47 is arranged so that the beam width B2 of the laser light L in the Y direction is shorter than the diameter of the aperture 49a and the beam width B1 in the Z direction is longer than the diameter of the aperture 49a.

[0087] In this example, the laser light L transmitted through the transfer mask 47 is irradiated onto the NA adjustment aperture 49 so that the Z direction component of the beam shape is contained within the effective projection area 49b and the Y direction component of the beam shape is contained within the aperture 49a. The NA adjustment aperture 49 reduces the NA difference by blocking part of the laser light L with the aperture 49a.

[0088] In this embodiment, a resin film 40 is placed on the surface, which is the processing surface, of a workpiece 41. In this example, a film made of polyimide is used as the resin film 40. The resin film 40 may be any film made of a resin material with excellent heat resistance. The resin film 40 may be a film made of a fluorine-based polymer material, such as a PTFE (polyfluoroethylene) film, a PPS (polyphenylene sulfide) film, or a PEEK (polyether ether ketone) film. The resin film 40 is an example of a "resin layer" according to the technology of the present disclosure.

[0089] 2.2 Operation Next, the operation of the laser processing apparatus 2A and the laser processing method of this embodiment will be described. Fig. 17 is a flowchart showing the steps of the laser processing method of this embodiment. The flowchart of the first embodiment differs from the flowchart of the comparative example in that step S100 is changed to step S100A and step S130 is changed to step S130A, but the rest is the same.

[0090] First, the resin film 40 is placed on the surface of the workpiece 41. For example, the resin film 40 is attached to the surface of the workpiece 41. The workpiece 41 on which the resin film 40 is placed is set on the table 33 of the moving stage 34 (S100A). The laser processing processor 32A executes the processes of steps S110 to S120, as in the comparative example, and then executes step S130A.

[0091] In step S130A, the laser processing processor 32A adjusts the position of the workpiece 41 in the X direction by controlling the amount of movement of the moving stage 34 based on the position data. As a result, the transfer position FP and the workpiece 41 are positioned relative to each other in the X direction so that the transfer position FP and the surface 40a of the resin film 40 coincide with each other.

[0092] After the positioning of the workpiece 41 is completed, laser processing is performed (S140). The processing content of step S140 is the same as the processing of the comparative example shown in FIG.

[0093] 18 shows laser processing of a workpiece 41 on which a resin film 40 is placed, using the laser processing apparatus 2A according to the first embodiment. As shown in Fig. 18, in this example, the laser light L transmitted through a transfer mask 47 has its NA difference reduced by an NA adjustment aperture 49 and is then irradiated onto a projection optical system 48. The projection optical system 48 then irradiates the laser light L so that the transfer position FP of the transferred image of the incident beam of laser light L coincides with the surface 40a of the resin film 40.

[0094] The NA adjustment aperture 49 reduces the NA difference of the laser light L incident from the transfer mask 47 and irradiates the laser light L onto the projection optical system 48. That is, the NA adjustment aperture 49 makes the first divergence angle θ1 and the second divergence angle θ2 approximately equal, as shown in Fig. 19. In this way, in this example, the workpiece 41 is drilled with the laser light L with a reduced NA difference.

[0095] 2.3 Actions and Effects As described above, the laser processing apparatus 2A of this embodiment is a laser processing apparatus 2A that irradiates a workpiece 41 having a resin film 40 placed on its processing surface with laser light L output by discharge excitation between a pair of electrodes 22a, 22b to form a hole in the workpiece 41, and is equipped with a laser device 3 that outputs laser light L in which a first divergence angle θ1 in the discharge direction between the pair of electrodes 22a, 22b is larger than a second divergence angle θ2 in a direction perpendicular to the discharge direction and the traveling direction of the laser light L, a transfer mask 47 that forms a circular pattern, an introduction optical system 46 that guides the laser light L to the transfer mask 47, a projection optical system 48 that images the circular pattern on the resin layer, and an NA adjustment aperture 49 that is arranged in the optical path of the laser light L and adjusts the difference between the first divergence angle θ1 and the second divergence angle θ2 to be smaller.

[0096] The laser processing method of this embodiment is a laser processing method for forming holes in a workpiece 41 having a resin film 40 arranged on a processing surface by irradiating the workpiece 41 with laser light L output by discharge excitation between a pair of electrodes 22a, 22b. The method includes a workpiece setting step S100A for setting the workpiece 41 having the resin film 40 arranged thereon on the table 33 of the moving stage 34, and a transfer positioning step S130 for relatively positioning the transfer position FP and the workpiece 41 so that the transfer position FP and the surface 40a of the resin film 40 coincide with each other. The laser output process outputs laser light L to a workpiece 41 on which a resin film 40 is placed, with a first divergence angle θ1 in the discharge direction between a pair of electrodes 22a, 22b being larger than a second divergence angle θ2 in a direction perpendicular to the discharge direction and the traveling direction of the laser light L; an optical introduction process guiding the laser light L to a transfer mask 47; a transfer pattern formation process forming a circular pattern; a transfer imaging process imaging the circular pattern on the resin film 40; and a divergence angle adjustment process adjusting the difference between the first divergence angle θ1 and the second divergence angle θ2 to be smaller.

[0097] According to the laser processing apparatus 2A and the laser processing method of this embodiment, the workpiece 41 on which the resin film 40 is disposed is drilled with the laser light L with a reduced NA difference, so the shape of the processed hole approaches a circle rather than the approximately ellipse shown in the comparative example. This makes it possible to suppress swelling and cracks around the processed hole.

[0098] In order to confirm the operation and effect of this embodiment, a plurality of resin films 40 having different thicknesses were placed on a workpiece 41, and holes were drilled using the laser processing device 2A. Here, a glass substrate having a thickness of 400 μm was used as the workpiece 41.

[0099] FIG. 20 is a graph showing the relationship between the thickness of the resin film 40 and the amount of swelling when drilling is performed on a glass substrate on which five resin films 40 with different thicknesses are arranged.

[0100] When a polyimide film with a thickness of 0.08 mm was used as the resin film 40, cracking of the workpiece 41 was suppressed. At the same time, the amount of swelling around the processed hole was reduced to 350 nm or less.

[0101] As the thickness of resin film 40 increased from 0.08 mm to 0.4 mm, the amount of swelling around the processed hole also decreased. Furthermore, when the thickness of resin film 40 was 0.4 mm or more, the amount of swelling decreased to about 150 nm.

[0102] As described above, it was confirmed that, according to the first embodiment, even with the high fluence laser light L required for machining a through hole, swelling and cracking around the machined hole in the workpiece 41 can be suppressed.

[0103] Furthermore, using the laser processing device 2A, holes were drilled on a glass substrate on which a 0.1 mm thick resin film 40 was disposed, at a variety of fluences and beam diameters. Fig. 21 is a graph showing the relationship between the fluence and beam diameter of the laser light L. As shown in Fig. 21, when the beam diameter was 20.9 μm and the fluence was 23 J / cm 2In the above cases, no cracks were generated and a through hole was formed. That is, it was confirmed that according to the first embodiment, cracks can be suppressed even with the fluence and beam diameter required to form a through hole.

[0104] 22 and 23 are SEM photographs showing the results of laser processing of a glass substrate on which a resin film 40 is disposed. According to the first embodiment, it was confirmed that clean through holes without cracks were formed as shown in Fig. 22, and that the shape of the through holes was improved to be circular as shown in Fig. 23.

[0105] 2.4 Modified NA adjustment aperture Next, we will explain modified examples of the NA adjustment aperture 49. In the first embodiment, the shape of the aperture 49a of the NA adjustment aperture 49 is circular, but the shape of the aperture 49a is not limited to circular and may be polygonal, such as rectangular.

[0106] 24 shows a first modified example of the NA adjustment aperture 49. The NA adjustment aperture 49 according to the first modified example has a square aperture hole 49a. In this example, the shape of the aperture hole 49a is a square with sides having approximately the same length as the beam width B2 of the laser light L transmitted through the transfer mask 47.

[0107] 25 shows a second modified example of the NA adjustment aperture 49. The NA adjustment aperture 49 according to the second modified example has a square aperture hole 49a. In this example, the shape of the aperture hole 49a is a square with sides shorter than the beam width B2 of the laser light L transmitted through the transfer mask 47.

[0108] 3. Second embodiment Next, a laser processing apparatus 2B and a laser processing method according to a second embodiment will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0109] 3.1 Configuration 26 is a schematic diagram showing the configuration of a laser processing apparatus 2B according to the second embodiment. The laser processing apparatus 2B according to the second embodiment includes a laser processing apparatus main body 4B instead of the laser processing apparatus main body 4A of the laser processing apparatus 2A according to the first embodiment.

[0110] The laser processing apparatus 2B differs from the laser processing apparatus 2A of the first embodiment in that it includes a beam expander 50 instead of the NA adjustment aperture 49. The other configurations of the laser processing apparatus 2B are the same as those of the laser processing apparatus 2A of the first embodiment. The beam expander 50 is an example of the "divergence angle adjustment optical system" according to the technique of the present disclosure.

[0111] As shown in Fig. 26, the beam expander 50 is disposed between the introduction optical system 46 and the transfer mask 47. The beam expander 50 is configured with at least one optical element that adjusts the beam width of the laser light L. Examples of the optical element include a prism and a cylindrical lens. The number of optical elements is selected as needed.

[0112] The NA difference can be reduced by expanding or reducing the beam width of the laser light L using the beam expander 50. The change in beam width and the change in divergence angle are inversely proportional to each other. Specifically, expanding the beam width reduces the divergence angle, and conversely, reducing the beam width increases the divergence angle. That is, since the first divergence angle θ1 is larger than the second divergence angle θ2, the NA difference can be reduced by expanding the beam width B1 (see FIG. 4) corresponding to the first divergence angle θ1 and reducing the first divergence angle θ1. Conversely, the NA difference can also be reduced by reducing the beam width B2 (see FIG. 4) corresponding to the second divergence angle θ2 and increasing the second divergence angle θ2.

[0113] 27 shows an example of the configuration of a beam width expansion type beam expander 50A. The beam expander 50A is composed of a right-angled isosceles triangular prism 501A and a prism 502A. The prism 501A is disposed upstream of the prism 502A.

[0114] Prism 501A and prism 502A are arranged, for example, at positions where the incident angle θN of laser light L incident on the refractive surface of prism 502A from prism 501A is the same as the apex angle θT of prism 502A. Preferably, prisms 501A and 502A are arranged so that the traveling direction of laser light L incident on beam expander 50A is parallel to the traveling direction of laser light L emitted from beam expander 50A.

[0115] The beam expander 50A reduces the NA difference by expanding the beam width B1 of the laser light L by a beam expansion ratio Mbc1 and reducing the first divergence angle θ1. The beam expansion ratio Mbc1 is the value obtained by dividing the first divergence angle θ1 by the second divergence angle θ2. The reduction ratio of the first divergence angle θ1 is the reciprocal of the beam expansion ratio Mbc1. Specifically, the beam expander 50A is configured to satisfy the following relational expressions (3) to (5). Mbc1 = θ1 / θ2 (3) BS1 = B1 × Mbc1 (4) BS2 = B2 (5) Here, BS1 is the beam width in the Z direction of the laser light L emitted from the beam expander 50A, and BS2 is the beam width in the Y direction of the laser light L emitted from the beam expander 50A.

[0116] Figure 28 shows an example of the configuration of a beam width reduction type beam expander 50B. The beam expander 50B is composed of right-angled isosceles triangular prisms 501B and 502B. Prism 501B is located downstream of prism 502B. Prism 501B and prism 502B have the same configuration as prism 501A and prism 502A shown in Figure 27, except that their positional relationship is reversed.

[0117] The beam expander 50B reduces the NA difference by reducing the beam width B2 of the laser light L by a beam reduction ratio Mbc2 and increasing the second divergence angle θ2. The beam reduction ratio Mbc2 is the value obtained by dividing the second divergence angle θ2 by the first divergence angle θ1. The expansion ratio of the second divergence angle θ2 is the reciprocal of the beam reduction ratio Mbc2. Specifically, the beam expander 50B is configured to satisfy the following relational expressions (6) to (8). Mbc2 = θ2 / θ1 (6) BS2 = B2 × Mbc2 (7) BS1 = B1 (8)

[0118] Fig. 29 shows another example of the configuration of a beam width expansion type beam expander. As shown in Fig. 29, a beam expander 50C includes a cylindrical concave lens 503C and a cylindrical convex lens 504C. The cylindrical concave lens 503C is arranged upstream of the cylindrical convex lens 504C. The cylindrical concave lens 503C and the cylindrical convex lens 504C are configured to expand the beam width B1 of the laser light L and reduce the first divergence angle θ1, thereby reducing the NA difference.

[0119] The cylindrical concave lens 503C and the cylindrical convex lens 504C each have a cylindrical surface with a central axis parallel to the optical axis V, and a flat surface parallel to the VH plane of the laser light L. The focal length of the cylindrical convex lens 504C is longer than the focal length of the cylindrical concave lens 503C. The cylindrical concave lens 503C and the cylindrical convex lens 504C are arranged so that the positions of their front focal points approximately overlap each other.

[0120] Fig. 30 shows another example of the configuration of a beam reduction type beam expander. As shown in Fig. 30, a beam expander 50D includes a cylindrical convex lens 504D and a cylindrical concave lens 503D. The cylindrical convex lens 504D is arranged upstream of the cylindrical concave lens 503D. The cylindrical convex lens 504D and the cylindrical concave lens 503D are configured to reduce the NA difference by reducing the beam width B2 of the laser light L and increasing the second divergence angle θ2.

[0121] The cylindrical convex lens 504D has the same configuration as the above-mentioned cylindrical convex lens 504C, but is arranged upstream after being inverted. The cylindrical concave lens 503D has the same configuration as the above-mentioned cylindrical concave lens 503C, but is arranged downstream after being inverted.

[0122] 3.2 Operation

[0123] Fig. 31 shows an outline of the operation of performing laser processing using a beam width expansion type beam expander 50A. As shown in Fig. 31, in this example, laser light L that has passed through optical device 36 is incident on beam expander 50A. The laser light L that has entered beam expander 50A is expanded from beam width B1 to beam width BS1 by prisms 501A and 502A and is then emitted.

[0124] In this example, the laser light L emitted from the beam expander 50A is irradiated onto the transfer mask 47 as shown in Fig. 32. Since the first divergence angle θ1 becomes smaller due to the expansion of the beam width B1 as described above, the second divergence angle θ2 of the laser light L irradiated onto the transfer mask 47 becomes substantially equal to the first divergence angle θ1 as shown in Fig. 33.

[0125] Of the laser light L irradiated onto the transfer mask 47, the laser light L that has passed through the pinhole 47a is irradiated onto the projection optical system 48. The projection optical system 48 irradiates the laser light L so that the transfer position FP of the transfer image of the incident beam of laser light L coincides with the surface 40a of the resin film 40. As a result, the workpiece 41 is drilled with the laser light L with a reduced NA difference.

[0126] In this example, when the beam width expanding type beam expander 50A is used, the beam width B1 is expanded to reduce the NA difference, and therefore the aspect ratio of the beam shape of the laser light L irradiated onto the transfer mask 47 increases. This makes it possible to form multiple pinholes 47a in the transfer mask 47.

[0127] In this example, drilling can be performed using a multi-point transfer mask 47B having multiple pinholes 47a, as shown in Figure 34. The multiple pinholes 47a are arranged in the Z direction in the multi-point transfer mask 47B, in which the beam width B1 is expanded. The laser light L emitted from the beam expander 50A is irradiated so as to cover the multiple pinholes 47a. The laser light L that has passed through the multiple pinholes 47a simultaneously forms multiple holes in the workpiece 41.

[0128] Fig. 35 shows an outline of the operation of performing laser processing using a beam width reduction type beam expander 50B. As shown in Fig. 35, in this example, laser light L that has passed through optical device 36 is incident on beam expander 50B. The laser light L that has entered beam expander 50B is reduced in beam width B2 to beam width BS2 by prisms 501B and 502B and is then emitted.

[0129] In this example, the laser light L emitted from the beam expander 50B is irradiated onto the transfer mask 47 as shown in Fig. 36. Since the second divergence angle θ2 increases due to the reduction in the beam width B2 as described above, the second divergence angle θ2 of the laser light L irradiated onto the transfer mask 47 becomes approximately equal to the first divergence angle θ1 as shown in Fig. 33.

[0130] Of the laser light L irradiated onto the transfer mask 47, the laser light L that has passed through the pinhole 47a is irradiated onto the projection optical system 48. The projection optical system 48 irradiates the laser light L so that the transfer position FP of the transfer image of the incident beam of laser light L coincides with the surface 40a of the resin film 40. As a result, the workpiece 41 is drilled with the laser light L with a reduced NA difference.

[0131] In this example, when the beam width reduction type beam expander 50B is used, the beam width B2 is reduced to reduce the NA difference, and therefore the aspect ratio of the beam shape of the laser light L irradiated onto the transfer mask 47 increases. Although the beam area becomes smaller, if the pinholes 47a are sufficiently small, it is possible to form multiple pinholes 47a in the transfer mask 47 in this example as well.

[0132] 3.3 Actions and Effects As described above, the laser processing apparatus 2B of this embodiment is a laser processing apparatus 2B that irradiates a workpiece 41 having a resin film 40 placed on its processing surface with laser light L output by discharge excitation between a pair of electrodes 22a, 22b to form a hole in the workpiece 41, and is equipped with a laser device 3 that outputs laser light L in which a first divergence angle θ1 in the discharge direction between the pair of electrodes 22a, 22b is larger than a second divergence angle θ2 in a direction perpendicular to the discharge direction and the traveling direction of the laser light L, a transfer mask 47 that forms a circular pattern, an introduction optical system 46 for guiding the laser light L to the transfer mask 47, a projection optical system 48 that images the circular pattern on the resin layer, and a beam expander 50 that is arranged in the optical path of the laser light L and adjusts the difference between the first divergence angle θ1 and the second divergence angle θ2 to be smaller.

[0133] According to the laser processing apparatus 2B and the laser processing method of this embodiment, the beam width of the laser light L is adjusted, and thereby the laser light L having a reduced NA difference is used to perform hole drilling on the workpiece 41 on which the resin film 40 is disposed. Therefore, the laser processing apparatus 2B according to the second embodiment can suppress swelling and cracks around the processed hole, similar to the first embodiment.

[0134] Furthermore, according to the laser processing apparatus 2B according to the second embodiment, the aspect ratio of the beam shape is large, so that a multipoint transfer mask can be suitably used.

[0135] In the second embodiment, the beam expander 50 is disposed between the introduction optical system 46 and the transfer mask 47, but the beam expander 50 may be disposed upstream of the introduction optical system 46.

[0136] 4. Modified examples of laser processing equipment In each of the above embodiments, the laser processing apparatus can be modified in various ways. For example, a laser processing apparatus 2C shown in Fig. 37 may be used as a laser processing apparatus that simultaneously drills a plurality of holes in a workpiece 41.

[0137] 37 shows a schematic configuration of a laser processing apparatus 2C. The laser processing apparatus 2C includes a laser processing apparatus main body 4C instead of the laser processing apparatus main body 4B of the laser processing apparatus 2B according to the second embodiment.

[0138] 4.1 Configuration The laser processing device body 4C differs from the laser processing device body 4B of the second embodiment in that it includes a multi-point transfer mask 47C, a fly-eye lens 55, and a condenser lens 56. The laser processing device body 4C uses a multi-point transfer mask 47C instead of the transfer mask 47.

[0139] In the laser processing apparatus main body 4C, the introduction optical system 46, the beam expander 50, the fly-eye lens 55, the condenser lens 56, and the multi-point transfer mask 47C are arranged so that the laser light L is incident in this order. The other configurations of the laser processing apparatus 2C are the same as those of the laser processing apparatus 2B of the second embodiment.

[0140] The fly-eye lens 55 is a lens in which a plurality of lenses are arranged, for example, in a honeycomb pattern, and is also called an integrator lens. The fly-eye lens 55 is arranged so that the focal plane on the emission side of the fly-eye lens 55 coincides with the focal plane on the incidence side of the condenser lens 56, and emits light so that the energy density of the laser light L incident on the condenser lens 56 is uniform.

[0141] 38 shows a first configuration example of a fly's eye lens 55. The fly's eye lens 55 according to the first configuration example includes a transparent body 55A, a cylindrical lens 55B, and a cylindrical lens 55C. The fly's eye lens 55 is formed by arranging a large number of cylindrical lenses 55B in parallel in one direction on one surface of the transparent body 55A, and by arranging a large number of cylindrical lenses 55C in parallel in a direction perpendicular to the direction of the cylindrical lenses 55B on the one surface on the other surface of the transparent body 55A.

[0142] 39 shows a second configuration example of the fly-eye lens 55. The fly-eye lens 55 according to the second configuration example is configured by orthogonally arranging lenses 55D and 55E, each of which is formed by arranging a large number of cylindrical lenses in parallel in one direction on one surface of a transparent body 55A.

[0143] The fly-eye lens 55 may also be configured by forming a lens array on a transparent substrate such as a synthetic quartz substrate by a photolithography process.The fly-eye lens 55 may also be configured by forming a pattern of a plurality of Fresnel lenses on a transparent substrate such as a synthetic quartz substrate by a photolithography process.

[0144] Figure 40 shows how the laser light L, whose beam width in the Y direction has been expanded to B2 by the beam expander 50, is irradiated onto the fly-eye lens 55. The fly-eye lens 55 itself has the function of reducing the NA difference. The beam expander 50 is arranged to irradiate the laser light L onto the entire surface of the fly-eye lens 55. Figure 41 shows how the laser light L, which has passed through the multi-point transfer mask 407, is irradiated onto the effective area 48A of the projection optical system 48.

[0145] In this example, the beam width of the laser light L in the Y direction is expanded to B2 by the beam expander 50. Therefore, the laser light L emitted from the beam expander 50 is irradiated onto the fly-eye lens 55 with a large NA difference. The fly-eye lens 55 reduces the NA difference of the laser light L incident on the condenser lens 56 and adjusts the laser light L so that the energy density becomes uniform. In this example, the fly-eye lens 55 is an example of a "divergence angle adjusting optical system" according to the technology of the present disclosure.

[0146] The condenser lens 56 is a lens that condenses the laser light L emitted from the fly-eye lens 55, and is disposed so that the focal plane on the emission side of the condenser lens 56 is on the multipoint transfer mask 407.

[0147] The multi-point transfer mask 47C is, for example, a plate-like member having a plurality of transmission holes formed therein that transmit a portion of the laser light L and block another portion of the laser light L. In this example, the transmission holes are made of a plurality of circular holes. When the laser light L passes through the plurality of transmission holes, the laser light L is split into a plurality of laser lights L to form a transfer pattern. When the transfer pattern is transferred to the workpiece 41, holes corresponding to the transfer pattern are formed in the workpiece 41.

[0148] 4.2 Operation Next, the operation of the laser processing apparatus 2C will be described, focusing on the operations that differ from the operation of the laser processing apparatus 2B according to the second embodiment.

[0149] As in this example, the laser light L incident on the laser processing device main body 4C is irradiated onto the multi-point transfer mask 47C via the high-reflection mirror 36a, the attenuator 52, the high-reflection mirror 36b, the introduction optical system 46, the beam expander 50, the fly-eye lens 55, and the condenser lens 56. By using the beam expander 50, the fly-eye lens 55, and the condenser lens 56, the NA difference of the laser light L is reduced and the laser light L with a uniform light intensity is irradiated onto the multi-point transfer mask 47C.

[0150] 41, a transfer pattern in which the NA difference of the laser light L is reduced is projected onto an effective area 48A of the projection optical system 48. This allows the laser processing apparatus 2C to perform drilling on the workpiece 41 with the laser light L in which the NA difference of the laser light L is reduced and the light intensity is made uniform.

[0151] 4.3 Actions and Effects As described above, the laser processing apparatus 2C is a laser processing apparatus 2C that irradiates a workpiece 41 having a resin film 40 placed on its processing surface with laser light L output by discharge excitation between a pair of electrodes 22a, 22b to form multiple holes in the workpiece 41, and is equipped with a laser device 3 that outputs laser light L in which a first divergence angle θ1 in the discharge direction between the pair of electrodes 22a, 22b is larger than a second divergence angle θ2 in a direction perpendicular to the discharge direction and the traveling direction of the laser light L, a multi-point transfer mask 47C that forms multiple circular patterns, an introduction optical system 46 for guiding the laser light L to the multi-point transfer mask 47C, a beam expander 50 and a condenser lens 56 formed between the multi-point transfer mask 47C and the introduction optical system 46, a projection optical system 48 that images the multiple circular patterns of the multi-point transfer mask 47C on a resin layer, and a fly's eye lens 55 that is arranged in the optical path of the laser light L and adjusts the difference between the first divergence angle θ1 and the second divergence angle θ2 to be smaller.

[0152] According to such a laser processing apparatus 2C and laser processing method, the laser light L with reduced NA difference and uniform light intensity is used to perform hole drilling on the workpiece 41 on which the resin film 40 is arranged. Therefore, the laser processing apparatus 2C according to the modified example can simultaneously form multiple holes with reduced swelling and cracking.

[0153] 5. Description of a method for manufacturing an electronic device using a laser processing apparatus according to the present disclosure FIG. 42 is a schematic diagram showing an example of the schematic configuration of an electronic device 600. The electronic device 600 shown in FIG. 42 includes an integrated circuit chip 601, an interposer 602, and a circuit board 603. The integrated circuit chip 601 is a chip-shaped integrated circuit board in which an integrated circuit is formed on, for example, a silicon substrate. The integrated circuit chip 601 is provided with a plurality of bumps 601B electrically connected to the integrated circuit. The interposer 602 includes an insulating substrate such as a glass substrate with a plurality of through holes formed therein, and a conductor is provided in each through hole to electrically connect the front and back of the substrate. One surface of the interposer 602 is provided with a plurality of lands connected to the bumps 601B provided on the integrated circuit chip 601, and each land is electrically connected to one of the conductors in the through hole. The other surface of the interposer 602 is provided with a plurality of bumps 602B, and each bump 602B is electrically connected to one of the conductors in the through hole. A plurality of lands connected to the respective bumps 602B are formed on one surface of the circuit board 603. The circuit board 603 also includes a plurality of terminals electrically connected to these lands.

[0154] FIG. 43 is a flowchart showing a method for manufacturing an electronic device 600. As shown in FIG. 43, the method for manufacturing an electronic device 600 in this description includes a first bonding process SP1 and a second bonding process SP2. In the first bonding process SP1, an integrated circuit chip 601 and an interposer 602 are bonded together. Specifically, each bump 601B of the integrated circuit chip 601 is placed on each land of the interposer 602, and the bumps 601B and the lands are electrically connected. In this way, the integrated circuit chip 601 and the interposer 602 are electrically connected. In the second bonding process SP2, the interposer 602 and a circuit board 603 are bonded together. Specifically, each bump 602B of the interposer 602 is placed on each land of the circuit board 603, and the bumps 602B and the lands are electrically connected. In this way, the integrated circuit chip 601 is electrically connected to the circuit board 603 via the interposer 602. Through the above processes, the electronic device 600 is manufactured.

[0155] The laser processing apparatus according to the technology of the present disclosure is used to manufacture the interposer 602 in the first bonding step SP1. Specifically, the laser light L that passes through the divergence angle adjustment optical system according to the technology of the present disclosure has a reduced NA difference and a uniform light intensity. This laser light L is irradiated onto the substrate of the interposer 602, which is the workpiece 41. At the irradiation position, the substrate of the interposer 602 is ablated to form a hole. The substrate of the interposer 602 is processed until this hole becomes a through hole, and then a conductor is placed inside the through hole. Note that the hole formed in the substrate of the interposer 602 is not limited to a through hole.

[0156] That is, the manufacturing method of the electronic device 600 includes a first bonding process SP1 in which an interposer 602 and an integrated circuit chip 601 are bonded to electrically connect them to each other, and a second bonding process SP2 in which the interposer 602 and a circuit board 603 are bonded to electrically connect them to each other, wherein the interposer 602 includes an insulating substrate having a plurality of through holes formed therein and a conductor provided in the plurality of through holes, and the plurality of through holes are formed by a laser processing method in which holes are formed at respective irradiation positions of a plurality of laser beams L irradiated onto the insulating substrate, and the laser processing method includes generating laser beams L in which a first divergence angle θ1 in the discharge direction between a pair of discharge electrodes is larger than a second divergence angle θ2 in a direction perpendicular to the discharge direction and the traveling direction of the laser beams L, reducing the difference between the first divergence angle θ1 and the second divergence angle θ2 of the laser beams L, and then focusing the laser beams L on an insulating layer to form through holes in the glass substrate.

[0157] The above description is intended to be illustrative rather than limiting. 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 appended claims.

[0158] Terms used throughout this specification and the appended claims should be interpreted as "open ended" terms. For example, the terms "include" or "including" should be interpreted as "not limited to what is stated as including." The term "having" should be interpreted as "not limited to what is stated as having." Additionally, the modifier "a" used in this specification and the appended claims should be interpreted as "at least one" or "one or more." Additionally, the term "at least one of A, B, and C" should be interpreted as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C," and should also be interpreted as including combinations other than "A," "B," and "C."

Claims

1. A laser processing device that irradiates a workpiece having a resin layer disposed on a processing surface with laser light output by discharge excitation between a pair of discharge electrodes to form a hole in the workpiece, a laser device that outputs laser light having a first divergence angle in a discharge direction between the pair of discharge electrodes that is larger than a second divergence angle in a direction perpendicular to the discharge direction and a traveling direction of the laser light; a transfer mask for forming a transfer pattern; an introduction optical system for guiding the laser light to the transfer mask; a projection optical system that forms an image of the transfer pattern on the resin layer; a divergence angle adjusting optical system that is disposed in an optical path of the laser light and adjusts the difference between the first divergence angle and the second divergence angle to be small; A laser processing device comprising:

2. The laser processing apparatus according to claim 1, the resin layer is formed of a polyimide or fluorine-based polymer material, The workpiece is a glass substrate.

3. The laser processing apparatus according to claim 1, The divergence angle adjustment optical system has a circular aperture and is disposed in the optical path between the transfer mask and the workpiece so that the laser light is irradiated onto the aperture.

4. The laser processing apparatus according to claim 1, The divergence angle adjustment optical system has a rectangular opening, and is disposed in the optical path between the transfer mask and the workpiece so that the laser light is irradiated onto the opening.

5. The laser processing apparatus according to claim 1, The divergence angle adjusting optical system is a beam expander that expands the beam width of the laser light at the first divergence angle.

6. The laser processing apparatus according to claim 1, The divergence angle adjusting optical system is a beam expander that reduces the beam width of the laser light at the second divergence angle.

7. The laser processing apparatus according to claim 1, The transfer mask is a multi-point transfer mask.

8. The laser processing apparatus according to claim 7, the transfer mask has a plurality of transmission holes formed therein; the divergence angle adjusting optical system is a fly-eye lens, A beam expander is provided for guiding the laser light to the fly-eye lens.

9. The laser processing apparatus according to claim 1, The laser beam is an ArF laser beam.

10. A laser processing method for forming a hole in a workpiece having a resin layer disposed on a processing surface by irradiating the workpiece with laser light output by discharge excitation between a pair of discharge electrodes, the method comprising: a workpiece setting step of setting the workpiece on which the resin layer is disposed on a table of a moving stage; a transfer positioning step of relatively positioning the transfer position and the workpiece so that the transfer position and the surface of the resin layer coincide with each other; a laser output step of outputting the laser light to the workpiece on which the resin layer is disposed, such that a first divergence angle in a discharge direction between the pair of discharge electrodes is larger than a second divergence angle in a direction perpendicular to the discharge direction and a traveling direction of the laser light; an optical introduction step of guiding the laser light to the transfer mask; a transfer pattern forming step of forming a transfer pattern; a transfer imaging step of imaging the transfer pattern onto the resin layer; a divergence angle adjusting step of adjusting the difference between the first divergence angle and the second divergence angle to be smaller.

11. The laser processing method according to claim 10, The divergence angle adjusting step is a step in which the laser light passes through a circular opening of a divergence angle adjusting optical system that is disposed in the optical path between the transfer mask and the workpiece.

12. The laser processing method according to claim 10, The divergence angle adjusting step is a step in which the laser light passes through a rectangular opening of a divergence angle adjusting optical system that is disposed in the optical path between the transfer mask and the workpiece.

13. The laser processing method according to claim 10, The divergence angle adjusting step is a step of expanding the beam width of the laser light at the first divergence angle.

14. The laser processing method according to claim 10, The transfer mask is a multi-point transfer mask.

15. a first bonding step of bonding the interposer and the integrated circuit chip together to electrically connect them; a second bonding step of bonding the interposer and the circuit board to electrically connect them to each other, the interposer includes an insulating substrate having a plurality of through holes formed therein, and a conductor provided in the plurality of through holes; the plurality of through holes are formed by a laser processing method in which holes are formed at respective irradiation positions of a plurality of laser beams irradiated onto the insulating substrate having a resin layer disposed on a processing surface; The laser processing method includes: a first divergence angle in a discharge direction between a pair of discharge electrodes, the first divergence angle being larger than a second divergence angle in a direction perpendicular to the discharge direction and a direction in which the laser light travels; a second divergence angle in a direction perpendicular to the discharge direction and a direction in which the laser light travels; a second divergence angle in a direction perpendicular to the discharge direction and a direction in which the laser light travels;

16. 16. The method for manufacturing an electronic device according to claim 15, The laser processing method includes reducing the difference between the first divergence angle and the second divergence angle by passing the laser light through a circular opening of a divergence angle adjustment optical system arranged in an optical path between a transfer mask and a workpiece.

17. 16. The method for manufacturing an electronic device according to claim 15, The laser processing method includes reducing the difference between the first divergence angle and the second divergence angle by passing the laser light through a rectangular opening of a divergence angle adjustment optical system arranged in an optical path between a transfer mask and a workpiece.

18. 16. The method for manufacturing an electronic device according to claim 15, The laser processing method includes reducing a difference between the first divergence angle and the second divergence angle by expanding a beam width related to the first divergence angle of the laser light.

19. 16. The method for manufacturing an electronic device according to claim 15, The laser processing method includes guiding the laser light to a multi-point transfer mask.

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