Substrate Processing Apparatus for Droplet Ejection Head and Substrate Processing Method for Droplet Ejection Head

Abstract

To provide a substrate processing device of a droplet discharge head and a substrate processing method of the droplet discharge head which can suitably form a through hole on a substrate of the droplet discharge head.SOLUTION: In a substrate processing device 100 of a droplet discharge head, a laser light source 1 emits laser light L1. A reflection type spatial modulator 2 generates a plurality of beams of processing laser light L2 by modulating the laser light L1. A rocking mirror 5 reflects the processing laser light L2. A condenser lens 6 condenses the processing laser light L2 on a substrate SU. An image formation optical system 3 constitutes a both-side telecentric optical system in which a reflection surface 21 of the reflection type spatial modulator 2 and an incidence surface 51 of the rocking mirror 5 are in a relation of image formation. A movement mechanism 7 moves the substrate SU. A gas blow mechanism 8 removes dust generated from the substrate SU in the time of through hole formation. The reflection type spatial modulator 2 corrects a phase hologram so as to form the plurality of through holes in the uniform shape and dimension by irradiating a prescribed position of the substrate SU with the plurality of beams of processing laser light L2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a substrate processing apparatus for a droplet ejection head and a method for processing a substrate of a droplet ejection head.

Background Art

[0002] Conventionally, an apparatus for forming small holes having a diameter of about 100 μm in a substrate using laser light has been known. This apparatus can form holes of an intended shape at an intended position with high accuracy. For example, an apparatus including a diffractive optical component, a galvanometer mirror, and an fsinθ lens that condenses a large number of branched beams is known (see, for example, Patent Document 1). However, in this apparatus, due to the quality of the diffractive optical component, lens distortion, etc., the actual hole processing position may deviate from the intended position and / or the actual hole processing shape may deviate from the intended shape.

[0003] In order to solve the above problems, an apparatus using a reflective spatial light modulator instead of a diffractive optical component has been known (see, for example, Patent Document 2). In this apparatus, the reflective spatial light modulator simultaneously condenses laser light for forming holes at a plurality of positions on the substrate using a phase hologram.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when forming through holes in a substrate constituting a droplet ejection head using the above apparatus, the through holes may not be suitably formed due to dust generated by laser processing.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a substrate processing apparatus for a droplet discharge head that can suitably form through holes in a substrate constituting the droplet discharge head, and a method for processing a substrate of the droplet discharge head.

Means for Solving the Problems

[0007] To solve the above problems, the invention according to claim 1 is A substrate processing apparatus for a droplet discharge head that forms a plurality of through holes having a hole diameter of 5 μm to 200 μm in a substrate constituting the droplet discharge head, A laser light source that emits laser light, A reflective spatial light modulator that modulates the laser light using a phase hologram to generate a plurality of processing laser lights for simultaneously forming the plurality of through holes arranged one-dimensionally or two-dimensionally on the substrate, A mirror that reflects the plurality of processing laser lights generated by the reflective spatial light modulator, A condenser lens that condenses each of the plurality of processing laser lights reflected by the mirror onto the substrate, An imaging optical system that constitutes a bilateral telecentric optical system in which the reflection surface of the reflective spatial light modulator and the incident surface of the mirror are in an imaging relationship, A moving mechanism that moves the substrate with respect to the plurality of processing laser lights, A gas blow mechanism that injects gas onto the substrate to remove dust generated from the substrate, and is provided with The reflective spatial light modulator corrects the phase hologram so as to simultaneously form a plurality of through holes having a uniform shape and dimensions at a predetermined position on the substrate by changing the reflection angle of the mirror to irradiate the plurality of processing laser lights at the predetermined position.

[0008] The invention according to claim 2 is the substrate processing apparatus for a droplet discharge head according to claim 1, It is provided with a polarization direction rotation mechanism that sequentially changes the polarization direction of the processing laser light, The polarization direction rotation mechanism includes a half-wave plate and a driving unit that rotates the half-wave plate around an axis along the optical axis direction of the processing laser beam.

[0009] The invention according to claim 3 is a substrate processing apparatus for a droplet discharge head according to claim 2, When the rotation speed of the half-wave plate is x rpm and the repetition frequency of the processing laser beam is y Hz, it is configured to satisfy the following (1). (1) x × 60 > y

[0010] The invention according to claim 4 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 3, The field curvature aberration generated with respect to the plurality of processing laser beams condensed by the imaging optical system and the condenser lens is 20 μm or less, and the astigmatism is 5 μm or less.

[0011] The invention according to claim 5 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 4, The imaging optical system is composed of a combined lens, a doublet lens, or an aspherical lens in which the convex surfaces of two plano-convex lenses face each other.

[0012] The invention according to claim 6 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 5, The condenser lens is an fsinθ lens.

[0013] The invention according to claim 7 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 6, The reflective spatial light modulator corrects the phase hologram so as to reduce the field curvature aberration generated with respect to the plurality of processing laser beams condensed by the condenser lens.

[0014] The invention according to claim 8 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 7, The reflection type spatial light modulator corrects the phase hologram so that the intensities of the plurality of processed laser beams condensed by the condenser lens become uniform.

[0015] The invention according to claim 9 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 8, The reflection type spatial light modulator corrects the phase hologram so that the actual processing pitch of the plurality of through holes becomes a desired processing pitch.

[0016] The invention according to claim 10 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 9, The reflection type spatial light modulator corrects the phase hologram so that the condensing positions of the plurality of processed laser beams by the condenser lens are different from the condensing position of the zero-order light.

[0017] The invention according to claim 11 is a substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 10, The moving mechanism moves the substrate one-dimensionally or two-dimensionally to form a continuous hole group on the substrate.

[0018] The invention according to claim 12 is a substrate processing apparatus for a droplet discharge head according to claim 11, When forming the hole group by moving the substrate by the moving mechanism, if a deviation occurs between the position of the substrate after being moved by the moving mechanism and the position on the substrate where the plurality of processed laser beams are to be irradiated, the reflection type spatial light modulator corrects the phase hologram so as to correct the deviation.

[0020] Claim 13 The invention described in is a method for processing a substrate of a droplet discharge head for forming a plurality of through holes having a hole diameter of 5 μm to 200 μm in a substrate, a light emitting step of emitting a laser beam, A generation step of modulating the laser beam using a phase hologram to generate a plurality of processing laser beams for simultaneously forming the plurality of through holes arranged in a one-dimensional or two-dimensional manner on the substrate; A reflection step of reflecting the plurality of processing laser beams generated in the generation step; A focusing step of focusing each of the plurality of processing laser beams reflected in the reflection step on the substrate; An imaging optical step of configuring a two-sided telecentric optical system in which the reflection surface in the generation step and the incident surface in the reflection step are in an imaging relationship; A moving step of moving the substrate with respect to the plurality of processing laser beams; A gas blow step of jetting a gas onto the substrate to remove dust generated from the substrate, comprising: In the generation step, the phase hologram is corrected so that a plurality of through holes having a uniform shape and dimensions are simultaneously formed at a predetermined position on the substrate by irradiating the predetermined position with the plurality of processing laser beams while changing the reflection angle in the reflection step.

[0021] Claim 14 The invention according to claim 13 is a method for processing a substrate of a droplet discharge head according to claim comprising a polarization direction rotation step of sequentially changing the polarization direction of the processing laser beam; In the polarization direction rotation step, a 1 / 2λ wavelength plate and a driving unit for rotating the 1 / 2λ wavelength plate around an axis along the optical axis direction of the processing laser beam are used.

[0022] Claim 15 The invention according to claim 14 is a method for processing a substrate of a droplet discharge head according to claim When the rotation speed of the 1 / 2λ wavelength plate is x rpm and the repetition frequency of the processing laser beam is y Hz, the following (1) is satisfied. (1) x × 60 > y

[0023] Claim 16 The invention according to claim 13 from15 A method for processing a substrate of a droplet ejection head according to any one of the following claims, the image plane curvature aberration generated with respect to the plurality of processed laser beams condensed by the imaging optical process and the condensing process is 20 μm or less, and the astigmatism is 5 μm or less.

[0024] Claim 17 The invention described in 13 from 16 A method for processing a substrate of a droplet ejection head according to any one of the following claims, In the imaging optical process, a combined lens, doublet lens, or aspherical lens in which the convex surfaces of two plano-convex lenses are combined facing each other is used.

[0025] Claim 18 The invention described in 13 from 17 A method for processing a substrate of a droplet ejection head according to any one of the following claims, In the condensing process, an fsinθ lens is used.

[0026] Claim 19 The invention described in 13 from 18 A method for processing a substrate of a droplet ejection head according to any one of the following claims, In the generation process, the phase hologram is corrected so as to reduce the image plane curvature aberration generated with respect to the plurality of processed laser beams condensed in the condensing process.

[0027] Claim 20 The invention described in 13 from 19 A method for processing a substrate of a droplet ejection head according to any one of the following claims, In the generation process, the phase hologram is corrected so that the intensities of the plurality of processed laser beams condensed in the condensing process become uniform.

[0028] Claim 21 The invention described in 13 from 20A method for processing a substrate of a droplet discharge head according to any one of the following items, In the generation step, the phase hologram is corrected so that an actual processing pitch of the plurality of through holes becomes a desired processing pitch.

[0029] Claim 22 The invention described in claim 13 From 21 A method for processing a substrate of a droplet discharge head according to any one of the following items, In the generation step, the phase hologram is corrected so that a condensing position of the plurality of processing laser beams in the condensing step is different from a condensing position of a zero-order beam.

[0030] Claim 23 The invention described in claim 13 From 22 A method for processing a substrate of a droplet discharge head according to any one of the following items, In the moving step, the substrate is moved one-dimensionally or two-dimensionally to form a continuous hole group in the substrate.

[0031] Claim 24 The invention described in claim 23 A method for processing a substrate of a droplet discharge head according to claim When forming the hole group by moving the substrate in the moving step, if a deviation occurs between a position of the substrate after the movement by the moving step and a position on the substrate where the plurality of processing laser beams are to be irradiated, the generation step corrects the phase hologram so as to correct the deviation.

Advantages of the Invention

[0032] According to the present invention, it is possible to provide a substrate processing apparatus for a droplet discharge head and a method for processing a substrate of a droplet discharge head that can suitably form through holes in a substrate constituting the droplet discharge head.

Brief Description of the Drawings

[0033]

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Embodiments for Carrying Out the Invention

[0034] [Overall Configuration of Substrate Processing Apparatus for Droplet Ejection Head] Hereinafter, the configuration of the substrate processing apparatus 100 for the droplet ejection head will be described with reference to each figure. FIG. 1 is a diagram showing the overall configuration of the substrate processing apparatus 100. Further, FIG. 2 is a block diagram showing the functional configuration of the substrate processing apparatus 100.

[0035] The substrate processing apparatus 100 is an apparatus that processes the substrate SU of the droplet ejection head by simultaneously irradiating the substrate SU with a plurality of processing laser beams L2 arranged one-dimensionally or two-dimensionally, thereby simultaneously forming a plurality of through-holes H (see FIG. 5) arranged one-dimensionally or two-dimensionally in the substrate SU of the droplet ejection head. The plurality of processing laser beams L2 are generated by modulating the laser beam L1 emitted from the laser light source with a reflective spatial light modulator. The substrate processing apparatus 100 includes a laser light source 1, a reflective spatial light modulator 2, an imaging optical system 3, a polarization direction rotation mechanism 4, a swing mirror 5, a condenser lens 6, a moving mechanism 7, a gas blow mechanism 8, and a control unit 9.

[0036] In the present invention, the substrate SU to be processed for substrate processing is, for example, a nozzle plate in which nozzle holes are formed, but any substrate may be used as long as it is a substrate constituting the droplet ejection head.

[0037] (Laser Light Source) The laser light source 1 emits a laser beam L1. The laser beam L1 emitted from the laser light source 1 has a wavelength in the near-infrared light region (for example, a wavelength of 1000 nm to 1200 nm), for example. The laser light source 1 emits the laser beam L1 as short pulse light. The pulse width of the laser beam L1 can be, for example, a pulse width from picoseconds to femtoseconds. The wavelength and pulse width of the laser beam L1 can be appropriately changed according to the material of the substrate SU and the like.

[0038] The laser beam L1 emitted from the laser light source 1 is reflected by the first mirror 11 and the second mirror 13, and is incident on the reflective spatial light modulator 2. Note that the second mirror 13 is, for example, a prism.

[0039] (Reflective spatial light modulator) The reflective spatial light modulator 2 makes the laser beam L1 emitted from the laser light source 1 incident on the reflection surface 21, modulates the incident laser beam L1, and generates a processing laser beam L2. The reflective spatial light modulator 2 is, for example, a spatial light modulator (SLM) using a liquid crystal on silicon (LCOS). The reflective spatial light modulator 2 modulates the laser beam L1 to generate a processing laser beam L2, and reflects and emits the processing laser beam L2 to the outside.

[0040] The reflective spatial light modulator 2 has pixel electrodes formed in an array on the reflection surface 21, counter electrodes provided facing the pixel electrodes, and liquid crystal disposed between the pixel electrodes and the counter electrodes. In this reflective spatial light modulator 2, a voltage is applied between each pixel electrode and the counter electrode to control the alignment state of the liquid crystal in the region corresponding to the pixel electrode, whereby the refractive index can be adjusted for each pixel electrode.

[0041] The laser beam L1 incident on the pixel electrode is reflected with a phase depending on the refractive index of the light at each pixel electrode on the reflecting surface 21. That is, the laser beam L1 is phase-modulated depending on the refractive index of each pixel electrode. Therefore, by appropriately adjusting the refractive index for each of the plurality of pixel electrodes on the reflecting surface 21 and phase-modulating the laser beam L1 incident on the reflective spatial light modulator 2 in units of pixel electrodes on the reflecting surface 21, the reflective spatial light modulator 2 can generate a processing laser beam L2 having an arbitrary form. The form of the processing laser beam L2 generated by the reflective spatial light modulator 2 is determined by a "phase hologram" representing the refractive index of each pixel electrode. Also, the voltage applied to each pixel electrode of the reflective spatial light modulator 2 can be determined based on the phase hologram.

[0042] In the present embodiment, the reflective spatial light modulator 2 phase-modulates the laser beam L1 using the above-described phase hologram to generate a plurality of processing laser beams L2 arranged one-dimensionally or two-dimensionally. One processing laser beam L2 forms one through-hole H when irradiated onto the substrate SU. That is, in the substrate processing apparatus 100 of the present embodiment, a plurality of processing laser beams L2 can be simultaneously irradiated onto the substrate SU to simultaneously form a plurality of through-holes H in the substrate SU.

[0043] (Imaging optical system) The imaging optical system 3 is an optical system disposed between the reflective spatial light modulator 2 and the swing mirror 5 and is composed of a first lens 31 and a second lens 32. The first lens 31 is disposed at a position away from the reflecting surface 21 of the reflective spatial light modulator 2 by the focal length of the first lens 31 on the optical path of the processing laser beam L2. The second lens 32 is disposed at a position away from the incident surface 51 of the swing mirror 5 by the focal length of the second lens 32 on the optical path of the processing laser beam L2. Also, the first lens 31 and the second lens 32 are disposed apart from each other by the same distance as the sum of the focal length of the first lens 31 and the focal length of the second lens 32. For example, the focal lengths of the first lens 31 and the second lens 32 are, for example, 100 mm to 200 mm.

[0044] The imaging optical system 3 having two lenses (first lens 31 and second lens 32) arranged as described above constitutes a bilateral telecentric optical system in which the reflecting surface 21 of the reflective spatial light modulator 2 and the incident surface 51 of the swing mirror 5 are in an imaging relationship. Thereby, the imaging optical system 3 can suppress the change in the wavefront shape and the increase in aberration of the processed laser beam L2 emitted from the reflective spatial light modulator 2 due to spatial propagation.

[0045] The first lens 31 and the second lens 32 used in the imaging optical system 3 are a combined lens formed by combining the convex surfaces of two plano-convex lenses facing each other. Note that instead of the combined lens of plano-convex lenses, a doublet lens or an aspherical lens may be used. A doublet lens is a lens formed by bonding a convex lens and a concave lens having different refractive indices. By using a combined lens of plano-convex lenses, a doublet lens, or an aspherical lens as the first lens 31 and the second lens 32, the aberration of the processed laser beam L2 generated by the imaging optical system 3 can be reduced.

[0046] Note that the type and shape of the imaging optical system 3 are selected so as to suppress the aberration within a range where the condensing position of the processed laser beam L2 can be corrected to the target position by the correction by the reflective spatial light modulator 2. Specifically, when a combined lens of plano-convex lenses is used for the imaging optical system 3, it is desirable that the field curvature aberration that affects the height of the condensing position correctable by the reflective spatial light modulator 2 be 20 μm or less. The field curvature aberration of the imaging optical system 3, which is a combined lens of plano-convex lenses, is, for example, 15 μm. Also, for the astigmatism difference that is difficult to correct by the reflective spatial light modulator 2, it is desirable that it be 5 μm or less. On the other hand, when a doublet lens or an aspherical lens is used for the imaging optical system 3, it is desirable that the field curvature aberration of this imaging optical system 3 be, for example, 60 μm or less.

[0047] (Polarization direction rotation mechanism) The polarization direction rotation mechanism 4 rotates the polarization direction of the processed laser beam L2. Specifically, the polarization direction rotation mechanism 4 includes a 1 / 2λ wave plate 41 and a drive unit 42 that rotates the 1 / 2λ wave plate 41 around an axis along the optical axis direction of the processed laser beam L2.

[0048] In laser processing, depending on the polarization direction of the processing laser beam L2, there will be a bias in the processing amount of the substrate SU. Therefore, when forming a circular through-hole H that serves as the nozzle of the droplet ejection head, it is preferable that the processing laser beam L2 be circularly polarized.

[0049] Conventionally, by making the incident light enter so that the azimuth angle of the polarization direction of the incident light is 45° with respect to the fast axis or the slow axis of the quarter-wave plate, the linearly polarized processing laser beam L2 can be changed to circularly polarized light. However, when the light enters at an azimuth angle other than 45°, the processing laser beam L2 becomes elliptically polarized instead of circularly polarized, and there will be a bias in the processing amount of the substrate SU. Therefore, it is necessary to precisely align the positions of the respective devices every time processing is performed, which is troublesome.

[0050] On the other hand, in the present embodiment, the processing laser beam L2 passes through a half-wave plate 41 that is rotating around an axis along the optical axis direction of the processing laser beam L2 by a driving unit 42. Therefore, as shown in FIG. 3, the processing laser beam L2 becomes linearly polarized light with different vectors. As a result, the bias in the processing amount of the substrate SU can be easily reduced.

[0051] Note that the rotation speed of the half-wave plate 41 by the driving unit 42 is preferably at least equal to or higher than the repetition frequency of the processing laser beam L2. Specifically, when the rotation speed of the half-wave plate 41 is x rpm and the repetition frequency of the processing laser beam L2 is y Hz, it is preferable that the rotation speed satisfies x × 60 > y. By doing so, since the vector of the processing laser beam L2 can be in any direction, the bias in the processing amount of the substrate SU can be further reduced.

[0052] Note that the rotation speed of the 1 / 2λ wavelength plate 41 and the repetition frequency of the processing laser beam L2 are not limited to a fixed combination. That is, after the user configures the repetition frequency of the processing laser beam L2 to be changeable, the rotation speed of the 1 / 2λ wavelength plate 41 may be automatically changed according to the changed repetition frequency.

[0053] In addition, the installation location of the polarization direction rotation mechanism 4 is not limited to the location between the second lens 32 and the swing mirror 5 as shown in FIG. 1. It may be on the optical path at least behind the reflection type spatial light modulator 2 and in front of the condenser lens 6. However, in the following description, it will be described as being installed at the location shown in FIG. 1.

[0054] (Swing mirror) The swing mirror 5 is a mirror that reflects the processing laser beam L2 that has passed through the 1 / 2λ wavelength plate 41 toward the condenser lens 6. The swing mirror 5 is rotatable about an axis A1 perpendicular to the propagation direction of the processing laser beam L2, and the angle of the incident surface 51 of the swing mirror 5 with respect to the propagation direction of the processing laser beam L2 can be changed. Thereby, the swing mirror 5 changes the reflection angle of the processing laser beam L2 on the incident surface 51, and can irradiate the processing laser beam L2 within a predetermined range of the substrate SU placed on the moving mechanism 7.

[0055] (Condenser lens) The condenser lens 6 is disposed between the swing mirror 5 and the substrate SU, and condenses each of the plurality of processing laser beams L2 reflected by the swing mirror 5 onto the substrate SU. The pupil position of the condenser lens 6 is made to coincide with the incident surface 51 of the swing mirror 5. Thereby, the plurality of processing laser beams L2 emitted from the condenser lens 6 become telecentric, and thus enter perpendicularly to the plane of the substrate SU. Each processing laser beam L2 condensed on the substrate SU forms a through hole H in the substrate SU. Note that the condenser lens 6 can change the distance from the substrate SU by a moving mechanism (not shown). The condenser lens 6 is, for example, an fsinθ lens having a focal length of 50 mm to 150 mm.

[0056] In the substrate processing apparatus 100, the above-described imaging optical system 3 and condenser lens 6 are selected such that the field curvature aberration generated with respect to the processed laser beam L2 condensed by the condenser lens 6 is 20 μm or less. As a result, the change in the irradiation state of the processed laser beam L2 due to the position of the substrate SU is reduced, so that a plurality of through holes H having uniform shapes and dimensions can be formed over a wide range of the substrate SU.

[0057] (Moving mechanism) The moving mechanism 7 moves the substrate SU with respect to a plurality of processed laser beams L2 condensed by the condenser lens 6. Specifically, the moving mechanism 7 includes a stage 71 on which the substrate SU is placed, and a stage moving unit 72 that moves the stage 71 three-dimensionally (in the up-down, left-right, and normal directions of the paper surface in FIG. 1). By moving the substrate SU linearly (in the left-right direction or the normal direction of the paper surface in FIG. 1) with respect to a plurality of processed laser beams L2 by the moving mechanism 7, a group of holes arranged linearly and continuously can be formed in the substrate SU. Further, by moving the substrate SU two-dimensionally (in the left-right direction and the normal direction of the paper surface in FIG. 1) with respect to a plurality of processed laser beams L2, a group of holes arranged two-dimensionally can be formed in the substrate SU.

[0058] (Gas blowing mechanism) FIG. 4A is an enlarged view of the vicinity of the gas blowing mechanism 8 in FIG. 1. As shown in FIG. 4A, specifically, the gas blowing mechanism 8 is a device that blows and removes dust generated during the processing of the substrate SU by injecting a high-pressure assist gas (e.g., O 2 or N 2 ) having sufficient transparency with respect to the wavelength of the processed laser beam L2 onto the substrate SU irradiated with a plurality of processed laser beams L2 condensed by the condenser lens 6. Note that the gas blown by the gas blowing mechanism 8 may be air.

[0059] The gas blow mechanism 8 and the processing part of the processing laser beam L2 on the substrate SU are maintained in a positional relationship such that they always have a constant distance. Specifically, the distance is preferably 1 to 30 mm. In this case, by setting the flow velocity at the nozzle outlet of the gas blow mechanism 8 to at least 80 mm / sec or more, preferably 120 mm / sec or more, dust can be sufficiently removed from the substrate SU.

[0060] Also, it is preferable that the gas blow mechanism 8 is provided at a position where the angle θ formed by the gas blow mechanism 8 and the substrate SU shown in FIG. 4A satisfies 15° < θ ≤ 90°. Moreover, it is still more preferable that the gas blow mechanism 8 is provided at a position where 22.5° ≤ θ ≤ 45°. When the gas blow mechanism 8 is provided at such a position, dust generated from the substrate SU can be suitably removed.

[0061] A configuration example of the gas blow mechanism 8 when θ = 90° is shown in FIG. 4B. In this configuration, the gas blow mechanism 8 is arranged coaxially with the optical axis of the processing laser beam L2, and ejects assist gas taken in from the gas inlet on the side surface portion from the gas nozzle. This is for the purpose of preventing the gas blow mechanism 8 from interfering with the processing laser beam L2.

[0062] Note that in this configuration, an example of a configuration in which a window lens 81 that transmits the processing laser beam L2 is provided is shown, but it is not limited thereto. Also, in FIG. 4B, as the stage 71, a plate-shaped one is illustrated, but a portion that abuts on the processing part of the substrate SU may be an opening so that dust can escape. Further, a dust collector may be provided so that the dust blown off by the gas blow mechanism 8 can be collected.

[0063] (Control Unit) The control unit 9 is a computer system composed of a CPU, a storage device (for example, RAM (Random Access Memory), ROM (Read Only Memory), etc.), and various interfaces, and controls each component of the substrate processing apparatus 100.

[0064] The control unit 9 may be implemented by a computer system with the above configuration as individual components, or may be implemented by a SoC (System on a Chip) in which the above configuration is integrated on one chip. The control unit 9 realizes the control of the substrate processing apparatus 100 described below by a program executable by the computer system constituting the control unit 9. Also, a part of the following control may be realized software-wise and the remaining control may be realized hardware-wise.

[0065] Specifically, the control unit 9 controls the laser light source 1 to emit the laser beam L1 from the laser light source 1. The control unit 9 determines the voltage applied to each pixel electrode of the reflective spatial light modulator 2 based on the phase hologram, and outputs the voltage to each pixel electrode to control the reflective spatial light modulator 2. The control unit 9 controls the rotation speed of the 1 / 2λ wave plate 41 in accordance with the repetition frequency of the processing laser beam L2. The control unit 9 rotates the swing mirror 5 to change the reflection angle of the processing laser beam L2 on the incident surface 51. The control unit 9 controls the stage moving unit 72 of the moving mechanism 7 to move the stage 71, thereby moving the substrate SU placed on the stage 71. The control unit 9 controls the gas blow mechanism 8 to inject gas toward the substrate SU.

[0066] [Hole forming operation by substrate processing apparatus] Hereinafter, the through-hole forming operation on the substrate SU by the substrate processing apparatus 100 having the above configuration will be described. Hereinafter, taking as an example the operation of forming a total of 32 tapered through-holes H whose hole diameters decrease from the front surface to the back surface of the substrate SU as shown in FIGS. 5 and 6, with 16 in a row and arranged in 2 columns vertically. Also, the substrate processing apparatus 100 modulates the laser beam L1 by the reflective spatial light modulator 2 to form the condensing points P of a total of 16 processing laser beams L2 arranged in 8 in a row and 2 columns vertically as shown in FIG. 7 on the substrate SU. That is, the substrate processing apparatus 100 can simultaneously form a total of 16 through-holes H arranged in 8 in a row and 2 columns vertically. In addition, in the present embodiment, the hole diameter w of the through hole H of the nozzle shown in FIG. 6 is preferably in the range of 5 μm to 200 μm. More preferably, it is in the range of 10 μm to 50 μm.

[0067] FIG. 5 is a diagram showing an example of the formation of the through hole H as viewed from the surface of the substrate SU, and FIG. 6 is a diagram showing the cross-sectional shape of each through hole H. Further, FIG. 7 is a diagram showing an example of the arrangement of the processing laser beam L2. When forming the through hole H with the arrangement as shown in FIG. 5, in the substrate processing apparatus 100, the condensing point P of the processing laser beam L2 with the arrangement as shown in FIG. 7 is moved along the outer shape of the through hole H to be formed while moving the substrate SU upward by changing the angle of the incident surface 51 of the swing mirror 5, thereby forming the through hole H. At this time, as shown in FIG. 8, as the substrate SU is moved upward (that is, as the depth of the through hole H increases), the shape of the circular movement of the condensing point P is made smaller to form a tapered through hole H. After forming 16 through holes H with the processing laser beam L2 having the arrangement shown in FIG. 7, the substrate SU is moved laterally with respect to the processing laser beam L2, and the through hole H with the arrangement shown in FIG. 7 is formed again at a position adjacent to the specific position, thereby forming 32 through holes H with the arrangement as shown in FIG. 7.

[0068] Hereinafter, the through hole forming operation will be specifically described. First, the control unit 9 generates a model of the phase hologram for generating the processing laser beam L2. Specifically, a model of the phase hologram capable of simultaneously irradiating the processing laser beam L2 with the arrangement shown in FIG. 7 onto the substrate SU is generated. This model of the phase hologram is generated assuming that no aberration or the like occurs in the processing laser beam L2 condensed by the condenser lens 6. Hereinafter, this model of the phase hologram will be referred to as the "reference phase hologram".

[0069] Next, the control unit 9 corrects the reference phase hologram so that the irradiation state of the processing laser beam L2 does not change depending on the position of the substrate SU due to optical factors of the substrate processing apparatus 100. Specifically, the following corrections are made to the reference phase hologram. Note that all or part of the plurality of corrections described below may be applied to the reference phase hologram, or only any one of the plurality of corrections may be applied.

[0070] First, the reference phase hologram is corrected so as to reduce the field curvature aberration generated with respect to the processing laser beam L2 by the imaging optical system 3 and the condenser lens 6. The condensing points P (P1 to P8) of the processing laser beam L2 affected by the field curvature aberration are arranged at positions deviated from the substrate SU as shown in FIG. 9. Specifically, the condensing point P is shifted upward from the surface of the substrate SU. The shift increases as the distance from the irradiation center position of the plurality of processing laser beams L2 increases. For example, the condensing points P1 to P3, P6 to P8 at positions away from the irradiation center position of the plurality of processing laser beams L2 are arranged particularly above the surface of the substrate SU. As a result, if the reference phase hologram is not corrected, since the irradiation position of the processing laser beam L2 varies depending on the position of the substrate SU, a plurality of through holes H having different shapes and / or dimensions are formed depending on the position of the substrate SU. FIG. 9 is a schematic diagram showing the irradiation state of the processing laser beam affected by the field curvature aberration while emphasizing the influence of the aberration.

[0071] Therefore, when the condensing point P is shifted from the target position (that is, the surface of the substrate SU) due to the field curvature aberration, the reference phase hologram is corrected so as to generate the processing laser beam L2 in which the position of the condensing point P is changed in the direction of the target position by the distance by which the condensing point P is shifted from the target position.

[0072] For example, when the reference phase hologram is set to be formed on the surface of the substrate SU without considering the influence of the field curvature aberration, if the positions of the condensing points P1 to P8 formed by irradiating the processing laser beam L2 are actually arranged at positions above the substrate SU due to the field curvature aberration, as shown in FIG. 10, the reference phase hologram is corrected so that the condensing points Q1 to Q8 in the setting of the reference phase hologram of the processing laser beam L2 are arranged below the target irradiation position (the surface of the substrate SU). As a result, the condensing points R1 to R8 of the processing laser beam L2 are positioned on the surface of the substrate SU. FIG. 10 is a diagram showing an example of the arrangement of the condensing points (P1 to P8) before correcting the field curvature aberration, the condensing points (Q1 to Q8) in the setting after correcting the reference phase hologram to correct the field curvature aberration, and the condensing points (R1 to R8) of the processing laser beam after correction.

[0073] By correcting the setting of the reference phase hologram so as to generate the condensing points of the processing laser beam L2 deviated from the target irradiation position, the influence of the field curvature aberration generated on the processing laser beam L2 can be reduced. As a result, all the condensing points P of the plurality of processing laser beams L2 can be arranged at the target irradiation position (the surface of the substrate SU). That is, on the surface of the substrate SU, the condensing points P of the processing laser beam L2 are made the same according to the position of the substrate SU, and a plurality of through holes H having uniform shapes and dimensions can be formed in a wide range of the substrate SU.

[0074] Second, the reference phase hologram is corrected so that the intensities of the plurality of processing laser beams L2 condensed by the condenser lens 6 become uniform. Specifically, for example, as shown in FIG. 11, among the plurality of processing laser beams L2, the light intensity in the setting of the reference phase hologram of the processing laser beams L2 whose intensities are larger than those of the other processing laser beams L2, namely, the condensing points P3 and P5, is corrected so that the intensity of the processing laser beam in the setting of the reference phase hologram becomes weaker than that of the other processing laser beams. The amount of weakening the intensity of the laser beam is changed according to the intensity of the corresponding processing laser beam L2. Specifically, the amount of weakening the intensity of the laser beam is increased for the processing laser beam L2 having a larger intensity difference compared to the other processing laser beams L2, so that the intensities of all the condensing points P of the processing laser beam L2 become uniform.

[0075] Alternatively, the reference phase hologram may be corrected so as to increase the intensity of the processing laser beam L2 having an intensity smaller than that of the other processing laser beams L2 among the plurality of processing laser beams L2.

[0076] As described above, by correcting the reference phase hologram so that the intensities of the plurality of processing laser beams L2 condensed by the condenser lens 6 become uniform, the intensity of the processing laser beam L2 becomes uniform over a wide range of the substrate SU. Therefore, a plurality of through holes H having uniform shapes and dimensions can be formed over a wide range of the substrate SU.

[0077] Thirdly, the reference phase hologram is corrected so that the actual processing pitch of the plurality of through holes H becomes a desired processing pitch. For example, when the plurality of processing laser beams L2 are simultaneously irradiated onto the substrate SU, as shown in FIG. 12, consider the case where the processing pitch of the through holes H becomes larger at the side portions of the region irradiated with the processing laser beam L2 (d1 < d2, d1: pitch of the inner through holes H, d2: pitch of the outer through holes H). Note that the desired pitch of the through holes H is d1. FIG. 12 is a schematic diagram highlighting an example of a state where the processing pitch of the through holes is deviated.

[0078] In this case, as shown in FIG. 13, the reference phase hologram is corrected so that the irradiation pitch D2 of the processing laser beam L2 at the side portions becomes smaller than the irradiation pitch D1 of the processing laser beam L2 inside (that is, D2 < D1). Note that the irradiation pitch D1 of the processing laser beam L2 is the irradiation pitch determined by the reference phase hologram. FIG. 13 is a diagram showing an example of the arrangement of the condensing points in terms of the setting of the reference phase hologram for correcting the deviation of the processing pitch.

[0079] Thus, for example, when the processing pitch of the through holes H becomes larger than the desired processing pitch, the phase hologram is corrected so as to reduce the irradiation pitch of the processing laser beam L2 irradiated to the portion where the processing pitch of the through holes H has become larger. As a result, when the processing laser beam L2 is actually irradiated onto the substrate SU, the irradiation pitch of the processing laser beam L2 at the above portion becomes the same as the desired processing pitch of the through holes H. As a result, it is possible to suppress the change in the irradiation pitch of the plurality of processing laser beams L2 depending on the position of the substrate SU, so that a plurality of through holes H having a uniform processing pitch can be formed over a wide range of the substrate SU.

[0080] Fourthly, the reference phase hologram is corrected so that the condensing positions of the plurality of processing laser beams L2 by the condenser lens 6 are different from the condensing position of the zero-order light. The zero-order light here means the laser beam that has not been phase-modulated by the reflective spatial light modulator 2. Such zero-order light has a higher intensity than the processing laser beam L2 generated by phase modulation. As a result, when the substrate SU is processed with the zero-order light, the desired processing is not performed. Therefore, the reference phase hologram is corrected so that the zero-order light is not used for processing the substrate SU. Specifically, as shown in FIG. 14, the reference phase hologram is corrected such that the condensing point of the zero-order light is located away from the substrate SU while the condensing point P of the processing laser beam L2 is located at the target irradiation position on the substrate SU. FIG. 14 is a diagram showing an example of the positional relationship between the condensing points of the zero-order light and the processing laser beam L2.

[0081] Thus, by correcting the reference phase hologram so that the position of the condensing point of the processing laser beam L2 in the height direction is shifted from the focal position of the zero-order light so that the zero-order light is not used for processing the substrate SU, the zero-order light having a higher intensity than the processing laser beam L2 is not used for forming the through holes H, so that a plurality of through holes H having a uniform shape and dimensions can be formed over a wide range of the substrate SU.

[0082] After the reference phase hologram is corrected as described above, the control unit 9 determines the voltage to be applied to each pixel electrode of the reflective spatial light modulator 2 based on the corrected reference phase hologram, and outputs the determined voltage to the corresponding pixel electrode. As a result, the reflective spatial light modulator 2 can form a refractive index distribution (phase hologram) corresponding to the corrected reference phase hologram on the reflective surface 21.

[0083] After forming the phase hologram on the reflective surface 21, the control unit 9 causes the laser light source 1 to emit the laser light L1. As a result, the laser light L1 is incident on the reflective surface 21 of the reflective spatial light modulator 2. The laser light L1 incident on the reflective surface 21 is phase-modulated to generate the processing laser light L2. The processing laser light L2 generated by the reflective spatial light modulator 2 is condensed by the condenser lens 6 and irradiated onto the substrate SU.

[0084] After irradiating a plurality of processing laser lights L2 to a specific position of the substrate SU to simultaneously form a plurality of through holes H, the control unit 9 moves the substrate SU in the lateral direction by the moving mechanism 7 and irradiates the plurality of processing laser lights L2 to a position different from the previous time. As a result, for example, after irradiating the processing laser light L2 arranged as shown in FIG. 7 to a specific region of the substrate SU, by irradiating the processing laser light L2 arranged as shown in FIG. 6 to a region adjacent to the specific position of the substrate SU in the lateral direction, a group of holes in which 32 through holes H are arranged in the lateral direction as shown in FIG. 5 can be formed.

[0085] Note that instead of moving the substrate SU in the lateral direction by the moving mechanism 7, the angle of the incident surface 51 of the swing mirror 5 may be changed to move the region where processing is performed. When the reflection angle of the incident surface 51 of the processing laser light L2 is changed to irradiate the processing laser light L2 to different positions of the substrate SU, the incident position of the processing laser light L2 on the condenser lens 6 is different from the previous incident position. In this case, the aberration and the like generated for the current processing laser light L2 may be different from those at the previous irradiation. In such a case, the correction of the reference phase hologram described above can be further applied to irradiate the substrate SU with the processing laser light L2 in the same irradiation state as the previous time.

[0086] Further, when the substrate SU is moved by the moving mechanism 7 and the processing laser beam L2 is irradiated at different positions of the substrate SU, due to the mismatch between the moving direction by the moving mechanism 7 and the arrangement direction of the condensing point P shown in FIG. 7, the arrangement direction of the through holes H formed in the substrate SU may be shifted. In this case, for example, as shown in FIG. 15, in the through holes H formed in the previous time and the through holes H formed this time, the arrangement of the through holes H may be shifted from the arrangement of the other through holes H. FIG. 15 is a diagram showing an example of a state where the processing positions are different at the boundary portion between the through holes formed in the previous time and the through holes formed this time.

[0087] Therefore, when a deviation occurs between the direction in which the substrate SU is moved by the moving mechanism 7 and the direction in which the processing laser beam L2 is arranged on the substrate SU, the reference phase hologram is corrected so as to correct the deviation. For example, as shown in FIG. 15, when the position of the formed through hole H is inclined with respect to the moving direction by the moving mechanism 7, as shown in FIG. 16, the reference phase hologram is corrected so that the arrangement direction of each condensing point P of the processing laser beam L2 by the reference phase hologram is inclined in the direction opposite to the positional deviation shown in FIG. 15. FIG. 16 is a diagram showing an example of the arrangement of the set condensing points after correcting the reference phase hologram in order to correct the deviation of the formation position of the through hole caused by the movement of the moving mechanism.

[0088] In addition, when aberration or the like occurs in the processing laser beam L2 as the arrangement direction of the condensing point P is inclined, correction for eliminating the aberration or the like described above may be further applied to the phase hologram corrected so as to incline the arrangement direction of the condensing point P.

[0089] [Advantages of the Invention] As described above, a substrate processing apparatus 100 for a droplet ejection head that forms a plurality of through-holes H with a hole diameter of 5 μm to 200 μm in a substrate SU constituting the droplet ejection head includes a laser light source 1 that emits a laser beam L1, a reflective spatial light modulator 2 that modulates the laser beam L1 using a phase hologram to generate a plurality of processing laser beams L2 for simultaneously forming a plurality of through-holes H arranged one-dimensionally or two-dimensionally on the substrate SU, a mirror 5 that reflects the plurality of processing laser beams L2 generated by the reflective spatial light modulator 2, a condenser lens 6 that condenses each of the plurality of processing laser beams L2 reflected by the mirror 5 onto the substrate SU, an imaging optical system 3 that constitutes a bilateral telecentric optical system in which the reflection surface 21 of the reflective spatial light modulator 2 and the incident surface 51 of the mirror 5 are in an imaging relationship, a moving mechanism 7 that moves the substrate SU with respect to the plurality of processing laser beams L2, and a gas blow mechanism 8 that jets gas onto the substrate SU to remove dust generated from the substrate SU. The reflective spatial light modulator 2 corrects the phase hologram so as to simultaneously form a plurality of through-holes H having a uniform shape and dimensions at a predetermined position by changing the reflection angle of the mirror 5 to irradiate the plurality of processing laser beams L2 at a predetermined position on the substrate SU. According to this configuration, a plurality of through-holes H having a uniform shape and dimensions, which serve as nozzles of the droplet ejection head and require precision and uniformity, can be accurately formed over a wide range of the substrate SU. Further, according to this configuration, since the dust generated by the laser processing is removed by the gas blow mechanism 8, the through-holes H can be suitably formed.

[0090] Further, it includes a polarization direction rotation mechanism 4 that sequentially changes the polarization direction of the processing laser beam L2. The polarization direction rotation mechanism 4 includes a 1 / 2λ wavelength plate 41 and a drive unit 42 that rotates the 1 / 2λ wavelength plate 41 around an axis along the optical axis direction of the processing laser beam L2. According to this configuration, since the processing laser beams L2 become linearly polarized lights with different vectors, the bias in the processing amount of the through-holes H can be easily reduced.

[0091] Also, when the rotation speed of the 1 / 2λ wave plate 41 is x rpm and the repetition frequency of the processing laser beam L2 is y Hz, the following (1) is satisfied. (1) x × 60 > y According to this configuration, since the vector of the processing laser beam L2 can be in any direction, the deviation in the processing amount of the through holes H can be reduced more.

[0092] Also, the field curvature aberration generated for the plurality of processing laser beams L2 condensed by the imaging optical system 3 and the condenser lens 6 is 20 μm or less, and the astigmatism is 5 μm or less. According to this configuration, since the change in the irradiation state of the processing laser beam L2 due to the position of the substrate SU is reduced, a plurality of through holes H having uniform shapes and dimensions can be formed over a wide range of the substrate SU.

[0093] Also, the imaging optical system 3 is composed of a combined lens, a doublet lens, or an aspherical lens in which the convex surfaces of two plano-convex lenses face each other. According to this configuration, the aberration of the processing laser beam L2 generated by the imaging optical system 3 can be reduced.

[0094] Also, the condenser lens 6 is an fsinθ lens. According to this configuration, the aberration of the processing laser beam L2 can be reduced more.

[0095] Also, the reflective spatial light modulator 2 corrects the phase hologram so as to reduce the field curvature aberration generated for the plurality of processing laser beams L2 condensed by the condenser lens 6. According to this configuration, the irradiation state of the processing laser beam L2 due to the position of the substrate SU can be made the same, and a plurality of through holes H having uniform shapes and dimensions can be formed over a wide range of the substrate SU.

[0096] Also, the reflective spatial light modulator 2 corrects the phase hologram so that the intensities of the plurality of processing laser beams L2 condensed by the condenser lens 6 become uniform. According to this configuration, since the intensity of the processing laser beam L2 becomes uniform over a wide range of the substrate SU, a plurality of through holes H having uniform shapes and dimensions can be formed over a wide range of the substrate SU.

[0097] Further, the reflective spatial light modulator 2 corrects the phase hologram so that the actual processing pitch of the plurality of through holes H becomes the desired processing pitch. According to this configuration, since it is possible to suppress the irradiation pitch of the plurality of processing laser beams L2 from changing depending on the position of the substrate SU, a plurality of through holes H having a uniform processing pitch can be formed over a wide range of the substrate SU.

[0098] Further, the reflective spatial light modulator 2 corrects the phase hologram so that the condensing positions of the plurality of processing laser beams L2 by the condenser lens 6 are different from the condensing position of the zero-order light. According to this configuration, since the zero-order light having a higher intensity than the processing laser beam L2 is not used for forming the through holes H, a plurality of through holes H having uniform shapes and dimensions can be formed over a wide range of the substrate SU.

[0099] Further, the moving mechanism 7 moves the substrate SU one-dimensionally or two-dimensionally to form a continuous hole group on the substrate SU. According to this configuration, a hole group that is arranged in a one-dimensional or two-dimensional manner and continuously disposed on the substrate SU can be formed.

[0100] Further, when forming a hole group by moving the substrate SU by the moving mechanism 7, if there is a deviation between the position of the substrate SU after being moved by the moving mechanism 7 and the position where the plurality of processing laser beams L2 should be irradiated on the substrate SU, the reflective spatial light modulator 2 corrects the phase hologram so as to correct the deviation. According to this configuration, the hole group can be formed with higher accuracy.

[0101] [Modification Example] As described above, although one embodiment of the present invention has been described, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention.

[0102] For example, in the above embodiment, the reflective spatial light modulator 2 changes the reflection angle of the mirror 5 to irradiate a plurality of processed laser beams L2 generated using a phase hologram at a predetermined position on the substrate SU, thereby correcting the phase hologram so as to simultaneously form a plurality of through holes H having a uniform shape and size. However, this is not an essential configuration and may be provided as necessary.

[0103] In addition, the through holes H formed in the substrate SU by the substrate processing apparatus 100 are not limited to the tapered shape described above, and can have any shape such as stepped holes in which the hole diameter gradually decreases, holes having an elliptical or rectangular cross section.

[0104] Further, the substrate processing apparatus 100 can also form through holes H' uniformly arranged in the vertical and horizontal directions of the substrate SU as shown in FIG. 17 by two-dimensionally moving the substrate SU by the moving mechanism 7. FIG. 17 is a diagram showing another example of the through holes H' that can be formed in the substrate.

[0105] Also, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications including the scope of the invention described in the claims and its equivalent scope are possible.

Explanation of Reference Numerals

[0106] 100 Substrate processing apparatus 1 Laser light source 2 Reflective spatial light modulator 21 Reflective surface 3 Imaging optical system 4 Polarization direction rotation mechanism 41 1 / 2λ wavelength plate 42 Driving unit 5 Oscillating mirror (mirror) 51 Incident surface 6 Condensing lens 7 Moving mechanism 71 Stage 72 Stage moving unit 8 Gas blow mechanism 9 Control unit L1 Laser beam L2 Processing Laser Light P Focus Point SU Substrate H, H' Through-Holes

Claims

1. A substrate processing apparatus for a droplet ejection head that forms a plurality of through-holes with a hole diameter of 5 μm to 200 μm in a substrate constituting the droplet ejection head, comprising: a laser light source that emits laser light; a reflective spatial light modulator that modulates the laser light using a phase hologram to generate a plurality of processing laser lights for simultaneously forming the plurality of through-holes arranged one-dimensionally or two-dimensionally on the substrate; a mirror that reflects the plurality of processing laser lights generated by the reflective spatial light modulator; a condenser lens that condenses each of the plurality of processing laser lights reflected by the mirror onto the substrate; an imaging optical system that constitutes a bilateral telecentric optical system in which the reflecting surface of the reflective spatial light modulator and the incident surface of the mirror are in an imaging relationship; a moving mechanism that moves the substrate with respect to the plurality of processing laser lights; a gas blowing mechanism that injects gas against the substrate to remove dust generated from the substrate, and the reflective spatial light modulator corrects the phase hologram so as to simultaneously form a plurality of through-holes having a uniform shape and size at a predetermined position on the substrate by changing the reflection angle of the mirror to irradiate the plurality of processing laser lights at the predetermined position. A substrate processing apparatus for a droplet ejection head.

2. Comprising a polarization direction rotation mechanism that sequentially changes the polarization direction of the processing laser light, The polarization direction rotation mechanism includes a 1 / 2λ wave plate and a drive unit that rotates the 1 / 2λ wave plate around an axis along the optical axis direction of the processing laser light. The substrate processing apparatus for a droplet ejection head according to claim 1.

3. When the rotation speed of the 1 / 2λ wave plate is x rpm and the repetition frequency of the processing laser light is y Hz, the substrate processing apparatus for a droplet ejection head according to claim 2 is configured to satisfy the following (1). (1) x × 60 > y

4. The substrate processing apparatus for a droplet ejection head according to any one of claims 1 to 3, wherein the image plane curvature aberration generated with respect to the plurality of processing laser lights condensed by the imaging optical system and the condenser lens is 20 μm or less, and the astigmatism difference is 5 μm or less.

5. The substrate processing apparatus for a droplet ejection head according to any one of claims 1 to 4, wherein the imaging optical system is composed of a combined lens, a doublet lens, or an aspherical lens in which the convex surfaces of two plano-convex lenses face each other.

6. The condenser lens is an fsinθ lens, and the substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 5.

7. The reflection type spatial light modulator corrects the phase hologram so as to reduce the image curvature aberration generated with respect to the plurality of processing laser beams condensed by the condenser lens, and the substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 6.

8. The reflection type spatial light modulator corrects the phase hologram so that the intensities of the plurality of processing laser beams condensed by the condenser lens become uniform, and the substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 7.

9. The reflection type spatial light modulator corrects the phase hologram so that the actual processing pitch of the plurality of through holes becomes a desired processing pitch, and the substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 8.

10. The reflection type spatial light modulator corrects the phase hologram so that the condensing position of the plurality of processing laser beams by the condenser lens is different from the condensing position of the zero-order light, and the substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 9.

11. The moving mechanism moves the substrate one-dimensionally or two-dimensionally to form a continuous hole group on the substrate, and the substrate processing apparatus for a droplet discharge head according to any one of claims 1 to 10.

12. When forming the hole group by moving the substrate by the moving mechanism, if a deviation occurs between the position of the substrate after being moved by the moving mechanism and the position on the substrate where the plurality of processing laser beams are to be irradiated, the reflection type spatial light modulator corrects the phase hologram so as to correct the deviation, and the substrate processing apparatus for a droplet discharge head according to claim 11.

13. A method for processing a substrate of a droplet discharge head for forming a plurality of through holes having a hole diameter of 5 μm to 200 μm in the substrate of the droplet discharge head, An emitting step of emitting a laser beam, A generating step of modulating the laser beam using a phase hologram to generate a plurality of processing laser beams for simultaneously forming the plurality of through holes arranged one-dimensionally or two-dimensionally on the substrate, A reflecting step of reflecting the plurality of processing laser beams generated in the generating step, A condensing step of condensing each of the plurality of processing laser beams reflected in the reflecting step onto the substrate, An imaging optical process that constitutes a bilateral telecentric optical system in which the reflecting surface in the generation process and the incident surface in the reflection process are in an imaging relationship, A moving process of moving the substrate with respect to the plurality of processing laser beams, A gas blowing process of jetting a gas onto the substrate to remove dust generated from the substrate, and comprising: In the generation process, the phase hologram is corrected so as to simultaneously form a plurality of through holes having a uniform shape and size at a predetermined position on the substrate by irradiating the plurality of processing laser beams at the predetermined position on the substrate by changing the reflection angle in the reflection process, A method for processing a substrate of a droplet discharge head.

14. A polarization direction rotation process of sequentially changing the polarization direction of the processing laser beam is provided, The polarization direction rotation process uses a half-wavelength plate and a driving unit that rotates the half-wavelength plate around an axis along the optical axis direction of the processing laser beam. The method for processing a substrate of a droplet discharge head according to claim 13.

15. When the rotation speed of the half-wavelength plate is x rpm and the repetition frequency of the processing laser beam is y Hz, the method for processing a substrate of a droplet discharge head according to claim 14 that satisfies the following (1). (1)x×60>y

16. The method for processing a substrate of a droplet discharge head according to any one of claims 13 to 15, wherein the field curvature aberration generated with respect to the plurality of processing laser beams condensed by the imaging optical process and the condensing process is 20 μm or less, and the astigmatism difference is 5 μm or less.

17. The imaging optical process uses a combined lens, a doublet lens, or an aspherical lens in which the convex surfaces of two plano-convex lenses are opposed to each other. The method for processing a substrate of a droplet discharge head according to any one of claims 13 to 16.

18. The condensing process uses an fsinθ lens. The method for processing a substrate of a droplet discharge head according to any one of claims 13 to 17.

19. In the generation process, the phase hologram is corrected so as to reduce the field curvature aberration generated with respect to the plurality of processing laser beams condensed in the condensing process. The method for processing a substrate of a droplet discharge head according to any one of claims 13 to 18.

20. In the generation process, the phase hologram is corrected so that the intensities of the plurality of processing laser beams condensed in the condensing process become uniform. The method for processing a substrate of a droplet discharge head according to any one of claims 13 to 19.

21. The generation step corrects the phase hologram so that the actual processing pitch of the plurality of through holes becomes a desired processing pitch, and the method for processing a substrate of a droplet discharge head according to any one of claims 13 to 20.

22. The generation step corrects the phase hologram so that the condensing positions of the plurality of processing laser beams in the condensing step are different from the condensing position of the zero-order light, and the method for processing a substrate of a droplet discharge head according to any one of claims 13 to 21.

23. The moving step moves the substrate one-dimensionally or two-dimensionally to form a continuous hole group in the substrate, and the method for processing a substrate of a droplet discharge head according to any one of claims 13 to 22.

24. When the hole group is formed by moving the substrate in the moving step, if a deviation occurs between the position of the substrate after the movement by the moving step and the position on the substrate where the plurality of processing laser beams are to be irradiated, the generation step corrects the phase hologram so as to correct the deviation, and the method for processing a substrate of a droplet discharge head according to claim 23.

Images