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

Abstract

A laser processing method according to one aspect of the present disclosure comprises the steps of: depositing a product generated from a first glass substrate at a processing position of a second glass substrate by irradiating the first glass substrate with a first ultraviolet pulse laser under a first irradiation condition; and forming a hole by irradiating the processing position on which the product is deposited with a second ultraviolet pulse laser under a second irradiation condition different from the first irradiation condition.

Description

Technical Field

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

[0002] In recent years, in semiconductor exposure devices, as semiconductor integrated circuits become smaller and more highly integrated, there is a demand for higher resolution. Therefore, the wavelength of light emitted from the exposure light source is being shortened. For example, as a gas laser device for exposure, a KrF excimer laser device that outputs a laser with a wavelength of about 248.0 nm and an ArF excimer laser device that outputs a laser with a wavelength of about 193.4 nm are used.

[0003] In addition, since the pulse width of excimer laser is about several tens of nanoseconds and the wavelength is as short as 248.4 nm and 193.4 nm respectively, it is sometimes used for direct processing of polymer materials, glass materials, etc.

[0004] Chemical bonds in polymer materials can be cut by excimer lasers having photon energy higher than the bond energy. Therefore, it is known that polymer materials can be processed without heating using excimer lasers to produce beautiful processed shapes.

[0005] In addition, it is known that glass, ceramics, and the like have a high absorption rate for excimer lasers, and therefore even materials that are difficult to process using visible and infrared lasers can be processed using excimer lasers.

[0006] The spectral line width of the natural oscillation light of the KrF excimer laser device and the ArF excimer laser device is as wide as 350pm to 400pm. Therefore, if the projection lens is made of a material that allows ultraviolet rays such as KrF and ArF lasers to pass through, chromatic aberration may sometimes occur. As a result, the resolution may be reduced. Therefore, it is necessary to narrow the spectral line width of the laser output from the gas laser device to a degree where the chromatic aberration can be ignored. Therefore, in order to narrow the spectral line width, a narrowing module (LNM: Line Narrowing Module) including narrowing elements (etalon, grating, etc.) is sometimes provided in the laser resonator of the gas laser device. Hereinafter, the gas laser device whose spectral line width is narrowed is referred to as a narrowed gas laser device.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: U.S. Patent Application Publication No. 2020 / 0209760

[0010] Patent Document 2: U.S. Patent Application Publication No. 2022 / 0050382

[0011] Patent Document 3: U.S. Patent Application Publication No. 2017 / 0096361

[0012] Patent Document 4: U.S. Patent Application Publication No. 2019 / 0359515

[0013] Patent Document 5: U.S. Patent Application Publication No. 2004 / 0013951

[0014] Patent Document 6: International Publication No. 2022 / 079798 Summary of the invention

[0015] A laser processing method according to one aspect of the present disclosure includes the following steps: causing a product produced by a first glass substrate by irradiating a first ultraviolet pulse laser to the first glass substrate under a first irradiation condition to accumulate at a processing position on a second glass substrate; and forming a hole by irradiating the processing position where the product is accumulated with a second ultraviolet pulse laser under a second irradiation condition different from the first irradiation condition.

[0016] A laser processing device according to one aspect of the present disclosure comprises: an optical device that irradiates a first glass substrate and a second glass substrate with ultraviolet pulse laser output from the laser device; and a laser processing processor that controls the laser device and the optical device, wherein the laser processing processor causes a product generated from the first glass substrate by irradiating the first glass substrate with ultraviolet pulse laser under a first irradiation condition to be deposited at a processing position on the second glass substrate, and the laser processing processor causes the processing position where the product is deposited to be irradiated with ultraviolet pulse laser under a second irradiation condition that is different from the first irradiation condition.

[0017] A method for manufacturing an electronic device according to one aspect of the present disclosure includes the following steps: causing a product generated from a first glass substrate by irradiating a first ultraviolet pulse laser to the first glass substrate under a first irradiation condition to be deposited at a processing position on a second glass substrate; and forming a through hole by irradiating a second ultraviolet pulse laser to the processing position where the product is deposited under a second irradiation condition different from the first irradiation condition; bonding an interposer to an integrated circuit chip and electrically connecting them to each other, the interposer having a second glass substrate and a conductor arranged in the through hole; and bonding the interposer to a circuit substrate and electrically connecting them. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings, merely as examples.

[0019] Figure 1 This is a SEM image showing a porous product deposited by irradiating an alkali-free glass substrate with ultraviolet pulse laser light.

[0020] Figure 2It is a diagram schematically showing the configuration of a laser processing system according to a comparative example.

[0021] Figure 3 This is a diagram schematically showing the structure of a laser device.

[0022] Figure 4 This is a flowchart schematically showing the operation flow of the laser processing system of the comparative example.

[0023] Figure 5 This is a flowchart showing the operation flow during laser drilling processing.

[0024] Figure 6 This is a SEM image of the cross section after irradiation with one pulse.

[0025] Figure 7 This is a SEM image of the cross section after irradiation with five pulses.

[0026] Figure 8 This is a SEM image of the cross section after 10 pulses were irradiated.

[0027] Fig. 9 This is a diagram for explaining the state of performing laser drilling processing while maintaining a high aspect ratio.

[0028] Fig.10 This is a SEM image of a cross section after irradiation with 500 or more pulses.

[0029] Fig.11 The diagram schematically shows the first to fourth stages of laser drilling processing.

[0030] Fig.12 This is a microscope image obtained by photographing a plurality of holes formed by the laser processing method of the comparative example from the side surface of the workpiece.

[0031] Fig.13 : is a SEM image showing the surface of the workpiece after irradiation with three pulses.

[0032] Fig.14 This is a SEM image showing that the product deposited on the surface of the glass absorbs laser light.

[0033] Fig.15 This is a diagram showing the first step of depositing a product generated by laser ablation in a processing region.

[0034] Fig.16 This is a diagram showing the second step of laser drilling the processing area where the product is deposited.

[0035] Fig.17 It is a diagram showing the irradiation conditions for laser ablation and the irradiation conditions for laser drilling.

[0036] Fig.18 It is a diagram schematically showing the configuration of a laser processing system according to a second embodiment.

[0037] Fig.19 This is a flowchart schematically showing the operation flow of the laser processing system according to the second embodiment.

[0038] Fig. 20 This is a flowchart showing the flow of operations during laser ablation.

[0039] Fig.21 It is a diagram schematically showing the configuration of a laser processing system according to a third embodiment.

[0040] Fig. 22 This is a diagram showing an example of a laser ablation region set on the surface of a workpiece.

[0041] Fig.23 This is a diagram showing how products generated from the laser ablation region are deposited in the processed region.

[0042] Fig.24 This is a flowchart schematically showing the operation flow of the laser processing system according to the third embodiment.

[0043] Fig.25 This is a flowchart showing the flow of operations during laser ablation.

[0044] Fig.26 1 and 2 are diagrams showing modified examples of the laser ablation region.

[0045] Fig. 27 It is a diagram schematically showing the configuration of a laser processing system according to a fourth embodiment.

[0046] Fig.28 This is a diagram for explaining the operation flow during laser drilling processing.

[0047] Fig.29 It is a diagram for explaining the operation flow during laser drilling processing according to a modification of the fourth embodiment.

[0048] Fig.30 It is a diagram schematically showing the configuration of a laser processing system according to a fifth embodiment.

[0049] Fig.31 This is a diagram showing the relationship between the fluence of a pulse for laser ablation and the fluence of a pulse for laser drilling.

[0050] Fig.32 This is a flowchart schematically showing the operation flow of the laser processing system according to the fifth embodiment.

[0051] Fig.33 This is a flowchart showing the flow of operations for setting irradiation conditions.

[0052] Fig.34 This is a flowchart showing the flow of operations during ablation and laser drilling processing.

[0053] Fig.35 A diagram schematically showing the structure of an electronic device.

[0054] Fig.36 The present invention is a flow chart showing a method for manufacturing an electronic device. DETAILED DESCRIPTION

[0055] <Content>

[0056] 1. Explanation of terms

[0057] 1.1 Accumulation of products produced by laser ablation

[0058] 1.2 Alkali-free glass substrate

[0059] 1.3 Injection volume

[0060] 2. Comparative Example

[0061] 2.1 Structure

[0062] 2.2 Actions

[0063] 2.3 Topics

[0064] 3. First Implementation

[0065] 3.1 Laser processing method

[0066] 3.2 Effect

[0067] 4. Second Implementation

[0068] 4.1 Structure

[0069] 4.2 Actions

[0070] 4.3 Effect

[0071] 5. Third Implementation

[0072] 5.1 Structure

[0073] 5.2 Actions

[0074] 5.3 Effect

[0075] 6. Fourth Implementation

[0076] 6.1 Structure

[0077] 6.2 Actions

[0078] 6.3 Effect

[0079] 7. Fifth Implementation

[0080] 7.1 Structure

[0081] 7.2 Actions

[0082] 8. Method for manufacturing electronic devices

[0083] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and actions described in each embodiment may not all be necessary as the structures and actions of the present disclosure. In addition, the same reference numerals are marked on the same components, and repeated descriptions are omitted.

[0084] 1. Explanation of terms

[0085] 1.1 Accumulation of products produced by laser ablation

[0086] In the present disclosure, a phenomenon in which a glass substrate such as an alkali-free glass substrate is irradiated with ultraviolet pulse laser light having high energy, such as an excimer laser, to instantly sublimate an irradiated portion is referred to as laser ablation.

[0087] Substances such as molecules, atoms, ions, clusters, electrons, and photons that are sublimated by irradiation of ultraviolet pulse lasers collide with the atmosphere in a plasma state such as plume and move toward a substrate such as a workpiece. Substances in the plume that reach the substrate are deposited on the substrate in a porous state. In this disclosure, substances generated by laser ablation are referred to as products generated by laser ablation.

[0088] Figure 1 This shows a porous product deposited by irradiating an alkali-free glass substrate with ultraviolet pulse laser light.

[0089] 1.2 Alkali-free glass substrate

[0090] Alkali-free glass substrate refers to a substrate formed of glass that does not contain alkali components such as sodium and potassium. Usually, alkali-free glass is mainly composed of silicon dioxide, aluminum oxide or boron oxide, or alkaline earth metal oxides such as calcium oxide and barium oxide. Alkali-free glass substrates are used as insulating glass substrates for interposers that relay electrical connections between integrated circuit chips and circuit substrates.

[0091] 1.3 Injection volume

[0092] In the present disclosure, the fluence refers to the energy density of one pulse of ultraviolet pulsed laser. The unit of the fluence is J / cm2.

[0093] 2. Comparative Example

[0094] 2.1 Structure

[0095] Figure 2 The structure of the laser processing system 1 of a comparative example is schematically shown. In addition, the so-called comparative example is a form that the applicant recognizes that only the applicant knows, and it is not a publicly known example recognized by the applicant himself.

[0096] The laser processing system 1 includes a laser device 2 and a laser processing device 4 as main components. The laser processing system 1 is used for laser drilling processing for forming holes such as through holes in a glass substrate for an interposer.

[0097] The laser device 2 is a laser device that outputs ultraviolet pulse laser. For example, the laser device 2 is a discharge excitation laser device that uses F2, ArF, KrF, XeCl, XeF, etc. as a laser medium to output ultraviolet pulse laser. In the present disclosure, the laser device 2 is set to a KrF excimer laser device that outputs ultraviolet pulse laser with a central wavelength of 248.4nm. Hereinafter, the ultraviolet pulse laser output by the laser device 2 is referred to as laser L.

[0098] The laser device 2 and the laser processing device 4 are connected via an optical path tube 5. The optical path tube 5 is arranged on the optical path of the laser light L between the emission port of the laser device 2 and the incident port of the laser processing device 4.

[0099] The laser processing device 4 includes a laser processing processor 40, an optical device 41, a frame 42, a movable stage 43, and a workbench 44. The optical device 41 and the movable stage 43 are fixed on the frame 42.

[0100] The table 44 supports a workpiece 45. The workpiece 45 is a target to be processed by laser drilling by being irradiated with laser light L. The workpiece 45 is a glass substrate for an interposer, and is an alkali-free glass substrate transparent to the laser light L, for example.

[0101] The movable stage 43 supports the worktable 44. The workpiece 45 is fixed on the worktable 44. The movable stage 43 can move in the X direction, the Y direction, and the Z direction. By adjusting the position of the worktable 44, the position of the workpiece 45 can be adjusted. The X direction, the Y direction, and the Z direction are orthogonal to each other. The X direction and the Y direction are parallel to the surface 45a of the workpiece 45 on which the laser light L is incident. The Z direction is orthogonal to the surface 45a.

[0102] The moving stage 43 adjusts the position of the workpiece 45 under the control of the laser processing processor 40 so that the laser light L outputted from the optical device 41 is irradiated to a desired processing position in the processing area. In the present disclosure, the processing area refers to an area including one or more processing positions.

[0103] The optical device 41 includes a housing 41 a , high reflective mirrors 47 a and 47 b , an attenuator 49 , an introduction optical system 50 , a light shield 52 , and a projection optical system 53 , and transfers an image having the shape of a hole to be processed onto a surface 45 a of a workpiece 45 .

[0104] The high reflection mirror 47a is arranged to reflect the laser light L having passed through the optical tube 5, and the reflected laser light L enters the high reflection mirror 47b through the attenuator 49. The optical tube 5 and the housing 41a are purged with nitrogen gas, for example.

[0105] The attenuator 49 is arranged in the housing 41a on the optical path between the high reflector 47a and the high reflector 47b. The attenuator 49 includes, for example, two partial reflectors 49a and 49b and rotating stages 49c and 49d of the partial reflectors. The partial reflectors 49a and 49b are optical elements whose transmittance changes according to the incident angle of the laser light L. The partial reflectors 49a and 49b adjust the incident angle of the laser light L by rotating stages 49c and 49d so that the amount of the laser light L irradiated to the surface 45a of the workpiece 45 becomes a target value.

[0106] The high reflection mirror 47 b is arranged to reflect the laser light L that has passed through the attenuator 49 and to allow the reflected laser light L to enter the introduction optical system 50 .

[0107] The introduction optical system 50 includes a high reflective mirror 51, and is configured to perform Koehler illumination on the shutter 52 with a rectangular beam, for example, and the light intensity of the laser light L on the shutter 52 is uniform. In addition, the light intensity on the shutter 52 can also be made uniform via an illumination system including a fly-eye lens and a condenser lens (not shown).

[0108] The light shield 52 is formed by forming a pattern of a metal or dielectric multilayer film on a synthetic quartz substrate that transmits ultraviolet light. For example, a pattern for processing a hole having a diameter of 5 μm to 30 μm on the workpiece 45 is formed on the light shield 52. In addition, if the projection magnification of the projection optical system 53 is M, a pattern having a size of 1 / M times the processing size is formed on the light shield 52.

[0109] The projection optical system 53 is a reduction projection optical system that reduces and projects the image of the shutter 52. The projection optical system 53 is arranged so that the image of the shutter 52 is formed on the surface 45a of the workpiece 45. The projection optical system 53 may be a single lens or a lens group with corrected aberrations.

[0110] The laser processing processor 40 sends the target pulse energy Et and the emission trigger Tr to the laser device 2. The target pulse energy Et is a target value of the pulse energy of the laser light L. The emission trigger Tr is a trigger signal for causing the laser device 2 to output the laser light L of one pulse.

[0111] Figure 3 The structure of the laser device 2 is schematically shown. The laser device 2 includes an oscillator 20, a monitoring module 30, an aperture 35, and a laser processor 38. The oscillator 20 includes a chamber 21, an optical resonator composed of a rear mirror 25a and an output coupling mirror (OC: Output Coupler) 25b, a charger 23, and a power supply unit (PPM: Pulsed Power Module (Pulse Power Module) 22.

[0112] Windows 21a and 21b are provided in the chamber 21. Laser gas serving as a laser medium is sealed in the chamber 21.

[0113] In addition, an opening is formed in the chamber 21, and an electrical insulating plate 26 in which a plurality of feedthroughs 26a are embedded is provided to cover the opening. The PPM 22 is arranged on the electrical insulating plate 26. A pair of discharge electrodes 27a and 27b as main electrodes and a ground plate 28 are arranged in the chamber 21. The discharge surfaces of the discharge electrodes 27a and 27b are rectangular in shape.

[0114] In order to excite the laser medium by discharge, the discharge electrodes 27a and 27b are arranged so that the discharge surfaces face each other. The surface of the discharge electrode 27a opposite to the discharge surface is supported by the electrical insulating plate 26. The discharge electrode 27a is connected to the feedthrough 26a. The surface of the discharge electrode 27b opposite to the discharge surface is supported by the ground plate 28.

[0115] The PPM 22 includes a switch 22a, a charging capacitor (not shown), a pulse transformer, a magnetic compression circuit, and a peak capacitor. The peak capacitor is connected to the feed-through 26a via a connection portion (not shown). The charger 23 charges the charging capacitor based on control from the laser processor 38.

[0116] The switch 22a is turned on / off controlled by the laser processor 38. The laser processor 38 turns on the switch 22a according to the light emission trigger Tr sent from the laser processing processor 40.

[0117] When the switch 22a is turned on, the current flows from the charging capacitor to the primary side of the pulse transformer, and due to electromagnetic induction, the reverse current flows to the secondary side of the pulse transformer. The magnetic compression circuit is connected to the secondary side of the pulse transformer to compress the pulse width of the current pulse. The peak capacitor is charged by the current pulse. When the voltage of the peak capacitor reaches the breakdown voltage of the laser gas, insulation breakdown occurs in the laser gas between the discharge electrodes 27a and 27b, and discharge occurs. The discharge generates a pulse of laser light L.

[0118] The rear mirror 25a is formed by coating a high reflection film on a planar substrate. The output coupling mirror 25b is formed by coating a partial reflection film on a planar substrate. The cavity 21 is arranged between the rear mirror 25a and the output coupling mirror 25b. The laser light generated in the cavity 21 is amplified by the optical resonator and output from the output coupling mirror 25b.

[0119] The monitoring module 30 includes a beam splitter 31 and a light sensor 32. The beam splitter 31 is arranged on the optical path of the laser light L output from the output coupling mirror 25b, and reflects a part of the laser light L. The light sensor 32 is arranged at a position where the laser light L reflected by the beam splitter 31 is incident. The light sensor 32 measures the pulse energy of the laser light L and sends the measured value to the laser processor 38.

[0120] The laser processor 38 changes the charging voltage of the charger 23 based on the measured value of the pulse energy of the optical sensor 32 , thereby performing control so that the pulse energy of the laser light L output from the laser device 2 becomes the target pulse energy Et.

[0121] The aperture 35 is disposed on the optical path of the laser light L transmitted through the beam splitter 31. The aperture 35 is opened and closed in accordance with a command from the laser processor 38. The laser processor 38 controls the output of the laser light L from the laser device 2 by controlling the aperture 35.

[0122] 2.2 Action

[0123] Next, the operation of the laser processing system 1 according to the comparative example will be described. Figure 4 The operation flow of the laser processing system 1 of the comparative example is schematically shown. When performing laser drilling processing, the workpiece 45 is set on the table 44 of the movable stage 43. The laser processing processor 40 controls each part of the laser processing system 1 to perform laser drilling processing on the workpiece 45 using laser light L (step S10).

[0124] Figure 5 The following is a flow chart of the operation of laser drilling. First, the laser processing processor 40 sends the data of the target pulse energy Et required for laser drilling to the laser device 2 (step S100). Here, the laser processing processor 40 sets Et=Em. After receiving the data, the laser device 2 controls the chamber 21 and sends a preparation completion signal to the laser processing processor 40 when it is able to output the laser L with the target pulse energy Et.

[0125] The laser processing processor 40 determines whether a preparation completion signal is received from the laser device 2 (step S101). When the laser processing processor 40 determines that a preparation completion signal is received (step S101: Yes), it reads the irradiation conditions for laser drilling processing (step S102). The irradiation conditions include the target fluence Fm, the repetition frequency fm of the pulse of the laser L, and the number of irradiation pulses Nm. The irradiation conditions can also be read from an external device (not shown), via a network, or from an input device operated by an operator.

[0126] The laser processing processor 40 sets the transmittance of the attenuator 49 to the transmittance Tm at which the fluence of the laser light L on the surface 45a of the workpiece 45 becomes the target fluence Fm (step S103). Here, the laser processing processor 40 uses the transmittance Tm calculated by the following equation (1), for example.

[0127] Tm=(1 / T')×Sm×(Fm / Em)···(1)

[0128] T' is the transmittance of the optical device 41 when the transmittance of the attenuator 49 is 100%. Sm is the area of ​​the transfer image of the light shield 52 on the surface 45a of the workpiece 45. In step S103, the laser processing processor 40 controls the incident angle of the partial reflection mirrors 49a and 49b by rotating the stages 49c and 49d so that the transmittance of the attenuator 49 becomes Tm.

[0129] The laser processing processor 40 sets data indicating an initial processing position in the processing area of ​​the workpiece 45 (step S104). The laser processing processor 40 controls the movable stage 43 based on the set data, thereby positioning the workpiece 45 in the XY direction (step S105). In addition, the laser processing processor 40 controls the movable stage 43 in the Z direction so that the position of the transfer image of the shutter 52 is substantially consistent with the surface 45a of the workpiece 45 (step S106).

[0130] The laser processing processor 40 sends the light trigger Tr to the laser device 2 based on the repetition frequency fm and the number of irradiation pulses Nm (step S107). As a result, the laser L is output from the laser device 2 synchronously with the light trigger Tr, and is incident on the laser processing device 4 via the optical path tube 5. The laser L is reflected by the high reflector 47a, dimmed by the attenuator 49, and then reflected by the high reflector 47b. The laser L reflected by the high reflector 47b is reflected by the high reflector 51 introduced into the optical system 50 and is incident on the shutter 52. The laser L after passing through the shutter 52 is incident on the projection optical system 53. The laser L output from the projection optical system 53 is imaged on the surface 45a of the workpiece 45 as an image of the shutter 52. Then, a hole is formed by laser ablation.

[0131] The laser processing processor 40 determines whether the laser drilling processing of the processing area is completed (step S108). The completion of the laser drilling processing means that the laser drilling processing is completed at all processing positions in the processing area. When the laser processing processor 40 determines that the laser drilling processing is not completed (step S108: No), it sets data indicating the next processing position (step S109) and returns the processing to step S105.

[0132] The laser processing processor 40 repeatedly executes steps S105 to S107 until the laser drilling process is completed. When the laser processing processor 40 determines that the laser drilling process is completed (step S108: Yes), the processing ends.

[0133] 2.3 Topics

[0134] Next, the problems of the laser processing method of the comparative example will be described. Figure 6 to Figure 8 This is a SEM (Scanning Electron Microscope) image of a cross section of a workpiece 45 after irradiation with one or more pulses of laser light L in the laser processing method of the comparative example. Figure 6 This is a SEM image of the cross section after irradiation with one pulse. Figure 7 This is a SEM image of the cross section after irradiation with five pulses. Figure 8 This is a SEM image of the cross section after 10 pulses were irradiated.

[0135] like Figure 6 As shown in FIG. 1 , after irradiation with one pulse, the surface 45a of the workpiece 45 does not change. During irradiation with one to three pulses, although the surface 45a is altered, the laser drilling process hardly progresses. Hereinafter, the stage in which the laser drilling process hardly progresses despite irradiation with the laser L is referred to as the first stage.

[0136] like Figure 7 As shown in FIG. 1 , after irradiation with 5 pulses, the porous product generated by laser ablation is ejected and deposited on the surface 45a and near the processed hole. Since the porous product has a high absorption rate for the laser L, it has the effect of promoting the laser drilling process. As the number of irradiation pulses increases, the amount of the product increases, and thus the absorption of the laser L further increases, as shown in FIG. Figure 8 As shown, the laser drilling process advances in the depth direction. In this way, during the irradiation of 4 to 10 pulses, the laser drilling process advances through the product of laser ablation. Hereinafter, the stage in which the laser drilling process advances through the product of laser ablation is referred to as the second stage.

[0137] Fig. 9The following describes the situation in which the laser drilling process is advanced while maintaining a high aspect ratio. During the irradiation of 10 to 499 pulses, the laser drilling process is advanced while the laser light L that is not absorbed by the product is self-converged inside the hole. The self-convergence is presumed to be caused by the waveguide effect caused by the inner wall of the hole being melted by the laser drilling process, thereby reflecting the laser light L on the inner wall. The tapered inner wall self-converges the laser light L at the front end of the hole through the waveguide effect, thereby advancing the laser drilling process while maintaining a high aspect ratio.

[0138] In addition, according to Fig. 9 As can be seen from the cross-sectional SEM image shown, porous products are also generated at the front end of the hole. Therefore, the inner wall of the hole reflects the laser L, and the front end maintains a high absorption state of the laser L, so the laser drilling process is advanced while maintaining a high aspect ratio. In addition, the products generated by laser ablation are also discharged from the entrance of the hole. Hereinafter, the stage in which the laser drilling process is advanced while maintaining a high aspect ratio is referred to as the third stage.

[0139] Fig.10 This is a SEM image of a cross section after irradiation with more than 500 pulses. Fig.10 In the process, the hole penetrates the workpiece 45. After the hole penetrates the workpiece 45, the inner diameter of the hole is kept small regardless of the number of irradiation pulses of the laser L irradiated to the hole. This is because the hole penetrates the workpiece 45, and almost all of the products generated by laser ablation are discharged to the outside from the front end of the hole. As a result, the absorption of the laser L is suppressed inside the hole, so the inner diameter of the hole is kept small regardless of the number of irradiation pulses. Hereinafter, the stage after the hole penetrates the workpiece 45 is referred to as the fourth stage.

[0140] Fig.11 The first to fourth stages of the laser drilling process are schematically shown. In the first stage, the surface 45a of the workpiece 45 hardly changes, and the laser drilling process hardly advances. In the second stage, the laser drilling process advances due to the product of laser ablation. In the third stage, the laser drilling process advances while maintaining a high aspect ratio due to the self-convergence of the laser L. In the fourth stage, after penetrating the workpiece 45, the inner diameter of the hole remains small.

[0141] Fig.12 4 is an optical microscope image of a plurality of holes formed by the laser processing method of the comparative example, taken from the side of the workpiece 45. Fig.12 As shown, according to the laser processing method of the comparative example, a hole with a high aspect ratio penetrating the workpiece 45 can be formed.

[0142] According to the laser processing method of the comparative example, a hole with a high aspect ratio is formed by continuously irradiating the workpiece 45 with pulses of laser light L. However, the pulses irradiated in the first stage deteriorate the surface 45a of the workpiece 45 but hardly contribute to the laser drilling process, so the cumulative number of irradiation pulses increases.

[0143] Fig.13 : is a SEM image showing the surface 45a of the workpiece 45 after irradiation with three pulses. Fig.13 As shown, it can be seen that the pulse irradiated in the first stage changes the surface 45a of the workpiece 45, but hardly contributes to the laser drilling process.

[0144] Therefore, the present disclosure provides a laser processing method, a laser processing apparatus, and a method for manufacturing an electronic device, which contribute to laser drilling processing from the first pulse of laser light L, thereby reducing the cumulative number of irradiation pulses.

[0145] 3. First Implementation

[0146] A laser processing method according to a first embodiment of the present disclosure will be described. Note that the same reference numerals are given to the same structures as those described above, and duplicate descriptions are omitted unless otherwise specified.

[0147] The applicant has found that by performing laser drilling processing on the basis of depositing the product generated by laser ablation in the processing area, the laser light L contributes to the laser drilling processing from the first pulse. In order to verify this effect, Fig.14 As shown in FIG. 1 , a hole is formed on a glass substrate by laser drilling, and a product generated by laser ablation is deposited on the surface of the glass substrate. Then, one pulse of laser light L is irradiated to four locations around the hole where the product is deposited. It is confirmed that the product deposited on the surface of the glass substrate absorbs the laser light L, and thus contributes to the laser drilling process from the first pulse.

[0148] 3.1 Laser processing method

[0149] Fig.15 and Fig.16 The laser processing method according to the first embodiment is conceptually shown. Fig.15 The first step of depositing the product generated by laser ablation in the processing area is shown. Fig.16 This shows the second step of laser drilling the processing area where the product is accumulated.

[0150] In the first step, a target substrate 60 made of the same material as the workpiece 45 is arranged so that its surface 61 is at a certain angle to the surface 45a of the workpiece 45. For example, the target substrate 60 is an alkali-free glass substrate. Then, in the atmosphere, a laser La capable of laser ablation is irradiated on the surface 61 of the target substrate 60. As a result, a plume PL is generated from the surface 61 of the target substrate 60, and a product 62 generated by laser ablation is deposited on the surface 45a of the workpiece 45.

[0151] In the second step, the surface 45a of the workpiece 45 on which the product 62 is deposited is irradiated with laser drilling capable laser light L. The product 62 is porous and has a high absorption rate for the laser light L, so it contributes to the laser drilling process from the first pulse and advances the laser drilling process.

[0152] The laser La used for laser ablation and the laser L used for laser drilling can be the same laser. The laser La and the laser L are, for example, ultraviolet pulse lasers with the same central wavelength, for example, the central wavelength is 248.4 nm.

[0153] In addition, the laser La is an example of the "first ultraviolet pulse laser" of the technology of the present invention. The laser L is an example of the "second ultraviolet pulse laser" of the technology disclosed in the present invention. In addition, the target substrate 60 is an example of the "first glass substrate" of the technology disclosed in the present invention. The workpiece 45 is an example of the "second glass substrate" of the technology disclosed in the present invention. In the present embodiment, the first glass substrate and the second glass substrate are different substrates.

[0154] Fig.17 Indicates the irradiation conditions for laser ablation and the irradiation conditions for laser drilling. Hereinafter, the irradiation conditions for laser ablation are referred to as "first irradiation conditions", and the irradiation conditions for laser drilling are referred to as "second irradiation conditions". The first irradiation condition and the second irradiation condition include at least one of the fluence, the repetition frequency, the number of irradiation pulses, and the pulse width.

[0155] like Fig.17 As shown, the fluence, repetition frequency and pulse width can be the same values ​​in the first irradiation condition and the second irradiation condition. In addition, the number of irradiation pulses is different in the first irradiation condition and the second irradiation condition. The number of irradiation pulses in the second irradiation condition is a value that depends on the thickness of the workpiece 45.

[0156] In addition, the first irradiation condition and the second irradiation condition include the irradiation positions of the first ultraviolet pulse laser and the second ultraviolet pulse laser. In the present embodiment, the laser La is irradiated to the target substrate 60 during laser ablation, and the laser L is irradiated to the workpiece 45 during laser drilling. Therefore, in the present embodiment, the irradiation positions are different between the first irradiation condition and the second irradiation condition.

[0157] Therefore, the laser processing method of the first embodiment includes: causing a product generated from the first glass substrate by irradiating the first glass substrate with a first ultraviolet pulse laser under a first irradiation condition to be deposited at a processing position of the second glass substrate; and forming a hole by irradiating the processing position where the product is deposited with a second ultraviolet pulse laser under a second irradiation condition different from the first irradiation condition.

[0158] 3.2 Effect

[0159] In the laser processing method of this embodiment, laser drilling is performed by irradiating the laser light L after the product 62 generated by laser ablation is deposited on the surface 45a of the workpiece 45, so that the laser light L contributes to the laser drilling process from the first pulse. Thus, the cumulative number of irradiation pulses can be reduced.

[0160] 4. Second Implementation

[0161] Next, as a second embodiment, a laser processing system 1a to which the laser processing method of the first embodiment is applied will be described. Note that the same reference numerals are given to the same configurations as those described above, and duplicate descriptions are omitted unless otherwise specified.

[0162] 4.1 Structure

[0163] Fig.18 The structure of the laser processing system 1a of the second embodiment is schematically shown. The structure of the laser processing device 4a of the laser processing system 1a is different from that of the laser processing system 1 of the comparative example. In addition to the structure of the laser processing device 4 of the comparative example, the laser processing device 4a further includes a target substrate 60, a high reflection mirror 64, and a linear stage 66.

[0164] The target substrate 60 is made of the same material as the workpiece 45 , such as an alkali-free glass substrate, as in the first embodiment. The target substrate 60 is fixed by a holder 63 so that its surface 61 faces the surface 45 a of the workpiece 45 at a certain angle.

[0165] The high reflective mirror 64 is connected to a linear stage 66 via a holder 65. The linear stage 66 moves the high reflective mirror 64 based on control from the laser processing processor 40. The linear stage 66 is a moving mechanism that moves the high reflective mirror 64 between a position inserted into the optical path of the laser light L between the projection optical system 53 and the workpiece 45 and a position retracted from the optical path.

[0166] When the high reflector 64 is inserted into the optical path of the laser L, it reflects the laser L and makes it incident on the surface 61 of the target substrate 60. When it is withdrawn from the optical path of the laser L, it makes the laser L incident on the surface 45a of the workpiece 45. In this way, in the present embodiment, the laser L is used for laser ablation and laser drilling. Therefore, in the present embodiment, the first ultraviolet pulse laser and the second ultraviolet pulse laser are ultraviolet pulse lasers output from the same laser device 2. In addition, in the present embodiment, the first ultraviolet pulse laser and the second ultraviolet pulse laser are selectively irradiated onto the first glass substrate and the second glass substrate.

[0167] 4.2 Action

[0168] Next, the operation of the laser processing system 1 a according to the second embodiment will be described. Fig.19 The operation flow of the laser processing system 1a of the second embodiment is schematically shown. The operation of the laser processing system 1a of this embodiment is different from that of the comparative example in that before the step S10 of laser drilling the workpiece 45, the step S20 of depositing the product 62 on the surface 45a of the workpiece 45 by laser ablation is performed.

[0169] Fig. 20 The operation flow during laser ablation is shown below: First, the laser processing processor 40 controls the linear stage 66 to insert the high reflection mirror 64 into the optical path of the laser light L (step S200).

[0170] The laser processing processor 40 sends data of the target pulse energy Et required for laser ablation to the laser device 2 (step S201). Here, the laser processing processor 40 sets Et=Ea. After receiving the data, the laser device 2 controls the chamber 21 and sends a preparation completion signal to the laser processing processor 40 when it is able to output the laser L with the target pulse energy Et.

[0171] The laser processing processor 40 determines whether a preparation completion signal is received from the laser device 2 (step S202). When the laser processing processor 40 determines that a preparation completion signal is received (step S202: Yes), it reads the irradiation conditions for laser ablation (step S203). The irradiation conditions include the target fluence Fa, the repetition frequency fa of the pulse of the laser L, and the number of irradiation pulses Na. The irradiation conditions can also be read from an external device (not shown), via a network, or from an input device operated by an operator.

[0172] The laser processing processor 40 sets the transmittance of the attenuator 49 to a transmittance Ta at which the fluence of the laser light L on the surface 61 of the target substrate 60 becomes the target fluence Fa (step S204). Here, the laser processing processor 40 uses the transmittance Ta calculated by the following equation (2), for example.

[0173] Ta=(1 / T')×Sa×(Fa / Ea)···(2)

[0174] Sa is an irradiation area of ​​the laser light L on the surface 61 of the target substrate 60. In step S204, the laser processing processor 40 controls the incident angles of the partial reflection mirrors 49a and 49b by rotating the stages 49c and 49d so that the transmittance of the attenuator 49 becomes Ta.

[0175] The laser processing processor 40 sets data indicating an initial processing position in a processing area of ​​the workpiece 45 (step S205). The laser processing processor 40 controls the movable stage 43 based on the set data, thereby positioning the workpiece 45 in the XY direction (step S206). In addition, the laser processing processor 40 controls the movable stage 43 in the Z direction so that the product 62 generated by laser ablation is deposited on the surface 45a of the workpiece 45 (step S207).

[0176] The laser processing processor 40 sends the light trigger Tr to the laser device 2 based on the repetition frequency fa and the number of irradiation pulses Na (step S208). As a result, the laser L is output from the laser device 2 synchronously with the light trigger Tr, and is incident on the laser processing device 4 via the optical path tube 5. The laser L is reflected by the high reflector 47a, dimmed by the attenuator 49, and then reflected by the high reflector 47b. The laser L reflected by the high reflector 47b is reflected by the high reflector 51 introduced into the optical system 50 and is incident on the shutter 52. The laser L after passing through the shutter 52 is incident on the projection optical system 53. The laser L output from the projection optical system 53 is reflected by the high reflector 64 and is incident on the surface 61 of the target substrate 60. As a result, the product 62 generated by ablation is deposited at the processing position on the surface 45a of the workpiece 45.

[0177] The laser processing processor 40 determines whether the accumulation of the product 62 is completed (step S209). The completion of the accumulation of the product 62 means that the accumulation of the product 62 at all processing positions in the processing area is completed. When the laser processing processor 40 determines that the accumulation of the product 62 is not completed (step S209: No), it sets data indicating the next processing position (step S210) and returns the process to step S206.

[0178] The laser processing processor 40 repeatedly executes step S206 to step S208 until the accumulation of the product 62 is completed. In addition, during laser ablation, high accuracy is not required for positioning the workpiece 45 in the Z direction, so step S207 may not be performed in subsequent repetitive cycles starting from the second time.

[0179] When the laser processing processor 40 determines that the laser drilling processing is completed (step S209: Yes), it controls the linear stage 66 to retract the high reflection mirror 64 from the optical path of the laser light L (step S211), and ends the processing.

[0180] Afterwards, in Fig.19 In step S10 shown, laser drilling is performed on each processing position where the product 62 is deposited. The processing of the laser processing processor 40 in step S10 is the same as that of the comparative example.

[0181] 4.3 Effect

[0182] The laser processing device 4a of this embodiment can use the laser light L output from the laser device 2 to perform the accumulation of the product 62 generated by laser ablation and the laser drilling processing of the processing position where the product 62 is accumulated. In this way, according to this embodiment, the accumulation of the product 62 and the laser drilling processing can be efficiently performed by one laser processing system 1a. In this embodiment, similarly to the first embodiment, the laser light L contributes to the laser drilling processing from the first pulse, so the cumulative number of irradiation pulses can be reduced.

[0183] In addition, in the present embodiment, the laser light L transmitted through the shading device 52 is irradiated to the target substrate 60 during laser ablation, but the shading device 52 may be retracted from the optical path of the laser light L during laser ablation. In this case, it is preferable to configure the laser processing device 4a so that the target substrate 60 can be arranged at the focal position of the projection optical system 53. Thus, even if the pulse energy of the laser light L output from the laser device 2 is the same, the fluence during laser ablation can be made higher than the fluence during laser drilling processing, and the accumulation amount of the product 62 can be increased.

[0184] In the present embodiment, the laser device 2 is set as an excimer laser device, but the laser device 2 is not limited to the excimer laser device. For example, the laser device 2 may also be a YAG laser device that outputs a laser with a wavelength of about 1.03 μm to 1.06 μm or a solid-state laser device including a nonlinear crystal that outputs the fourth harmonic of a fiber laser (wavelength of 257.5 nm to 266 nm).

[0185] 5. Third Implementation

[0186] Next, a laser processing system 1 b according to a third embodiment will be described. Note that the same reference numerals are given to the same configurations as those described above, and duplicate descriptions are omitted unless otherwise specified.

[0187] 5.1 Structure

[0188] Fig.21The structure of the laser processing system 1b of the third embodiment is schematically shown. The structure of the laser processing device 4b of the laser processing system 1b is different from that of the laser processing system 1a of the second embodiment. The laser processing device 4b is a device in which the target substrate 60, the high reflection mirror 64, and the linear stage 66 are deleted from the laser processing device 4a of the second embodiment. That is, the laser processing device 4b has the same structure as the laser processing device 4 of the comparative example.

[0189] 5.2 Action

[0190] In this embodiment, the laser processing processor 40 uses a portion of the surface 45a of the workpiece 45 as a laser ablation region, and deposits a product 62 generated by irradiating the laser ablation region with laser light L in the processing region. Therefore, in this embodiment, the first glass substrate and the second glass substrate of the technology disclosed in the present invention are both the workpiece 45 and are the same substrate.

[0191] Fig. 22 FIG. 4 shows an example of a laser ablation area Ra set on the surface 45a of the workpiece 45. Fig. 22 As shown, the laser processing processor 40 sets the peripheral portion of the processing region Rp on the surface 45a of the workpiece 45 as the laser ablation region Ra.

[0192] like Fig.23 As shown, the laser processing processor 40 deposits the product 62 generated by irradiating the laser ablation area Ra with the laser L in the processing area Rp. Hereinafter, the position where the laser ablation is generated by irradiating the laser L in the laser ablation area Ra is referred to as the laser ablation position. The laser processing processor 40 sequentially changes the laser ablation position in the laser ablation area Ra, thereby depositing the product 62 in the entire processing area Rp.

[0193] In the present embodiment, the irradiation position of the laser light L is different during laser ablation and laser drilling, and therefore the first irradiation condition and the second irradiation condition described above are different.

[0194] Fig.24 The operation flow of the laser processing system 1b of the third embodiment is schematically shown. In the operation of the laser processing system 1b of this embodiment, step S30 of depositing the product 62 by laser ablation is different from step S20 of the second embodiment. Hereinafter, the description overlapping with step S20 of the second embodiment will be appropriately omitted.

[0195] Fig.25 The operation flow during laser ablation is shown below. First, the laser processing processor 40 sends data on target pulse energy Et required for laser ablation to the laser device 2 (step S300). Here, the laser processing processor 40 sets Et=Ea.

[0196] The laser processing processor 40 determines whether or not a preparation completion signal is received from the laser device 2 (step S301). When the laser processing processor 40 determines that a preparation completion signal is received (step S301: Yes), it reads the irradiation conditions for laser ablation (step S302).

[0197] The laser processing processor 40 sets the transmittance of the attenuator 49 to a transmittance Ta at which the fluence of the laser light L on the surface 45 a of the workpiece 45 becomes the target fluence Fa (step S303 ).

[0198] The laser processing processor 40 sets data indicating the initial laser ablation position in the laser ablation area Ra (step S304). The laser processing processor 40 controls the movable stage 43 based on the set data, thereby positioning the workpiece 45 in the XY direction (step S305). In addition, the laser processing processor 40 controls the movable stage 43 in the Z direction so that the product 62 generated by the laser ablation is deposited on the surface 45a of the workpiece 45 (step S306).

[0199] The laser processing processor 40 sends the light trigger Tr to the laser device 2 based on the repetition frequency fa and the number of irradiation pulses Na (step S307). As a result, the laser L output from the projection optical system 53 is irradiated to the laser ablation position in the laser ablation area Ra. As a result, the product 62 generated by the ablation is accumulated in a part of the processing area Rp adjacent to the laser ablation position.

[0200] The laser processing processor 40 determines whether the accumulation of the product 62 is completed (step S308). The completion of the accumulation of the product 62 means that the accumulation of the product 62 in the processing area Rp is completed. When the laser processing processor 40 determines that the accumulation of the product 62 is not completed (step S308: No), it sets data indicating the next laser ablation position (step S309) and returns the process to step S305.

[0201] The laser processing processor 40 repeatedly executes steps S305 to S307 until the accumulation of the product 62 is completed. In addition, during laser ablation, high accuracy is not required for positioning the workpiece 45 in the Z direction, so step S306 may not be performed in subsequent repetition cycles starting from the second time.

[0202] When the laser processing processor 40 determines that the accumulation of the product 62 is completed (step S308 : Yes), the processing ends.

[0203] Afterwards, in Fig.24In step S10 shown, laser drilling is performed on the processing region Rp where the product 62 is deposited. The processing of the laser processing processor 40 in step S10 is the same as that of the comparative example.

[0204] 5.3 Effect

[0205] According to the present embodiment, the same effects as those of the second embodiment can be obtained, and the product 62 generated by ablation can be deposited in the processing region Rp without using the target substrate 60 .

[0206] In addition, in the present embodiment, during laser ablation, the laser light L that has passed through the shading device 52 is irradiated to the laser ablation region Ra, but during laser ablation, the shading device 52 may be retracted from the optical path of the laser light L. In this case, it is preferable to configure the laser processing device 4a so that the laser ablation region Ra can be arranged at the focal position of the projection optical system 53. Thus, even if the pulse energy of the laser light L output from the laser device 2 is the same, the fluence during laser ablation can be made higher than the fluence during laser drilling processing, and the accumulation amount of the product 62 can be increased.

[0207] In addition, in the present embodiment, the peripheral portion of one processing region Rp on the surface 45 a of the workpiece 45 is set as the laser ablation region Ra, but the invention is not limited thereto, and the laser ablation region Ra can be appropriately changed.

[0208] Fig.26 FIG. 4 shows a modified example of the laser ablation area Ra. Fig.26 In the embodiment, the laser ablation region Ra is set in a grid shape on the surface 45a of the workpiece 45. In this modification, the region divided by the grid-shaped laser ablation region Ra becomes the processing region Rp. In this way, when the laser ablation region Ra is made into a grid shape, the product 62 can be uniformly deposited in the processing region Rp.

[0209] In addition, the processing region Rp is preferably set to be substantially the same size as the interposer chip. In this case, the laser ablation region Ra is the region cut to separate the processing region Rp, so there is no waste and the entire workpiece 45 can be used to manufacture the interposer chip.

[0210] 6. Fourth Implementation

[0211] Next, a laser processing system 1 c according to a fourth embodiment will be described. Note that the same reference numerals are given to the same configurations as those described above, and duplicate descriptions are omitted unless otherwise specified.

[0212] 6.1 Structure

[0213] Fig. 27The structure of the laser processing system 1c of the fourth embodiment is schematically shown. The structure of the laser processing device 4c of the laser processing system 1c is different from that of the laser processing system 1b of the third embodiment. The laser processing device 4c includes a nozzle 70 and a rotating stage 71 in addition to the structure of the laser processing device 4b of the third embodiment.

[0214] The nozzle 70 is connected to a gas supply source 72 via a pipe 73. A gas flow control valve 74 is provided in the middle of the pipe 73. The nozzle 70 ejects the gas supplied from the gas supply source 72 toward the processing position on the surface 45a of the workpiece 45 to be irradiated with the laser light L. For example, the gas ejected from the nozzle 70 is a purge gas such as dry air.

[0215] In addition, the nozzle 70 is held on a rotating stage 71. The rotating stage 71 rotates the nozzle 70 around a rotation axis parallel to the Z direction. By rotating the nozzle 70, the direction of the gas ejected toward the processing position changes. The rotating stage 71 and the gas flow control valve 74 are controlled by the laser processing processor 40.

[0216] 6.2 Action

[0217] Next, the operation of the laser processing system 1c of the fourth embodiment will be described. In this embodiment, the laser ablation area is not set as in the third embodiment. In addition, in this embodiment, laser ablation, which is an operation different from the laser drilling process, is not performed, but the laser ablation generated during the laser drilling process is used to deposit the product 62 in the processing area. Specifically, in this embodiment, the gas ejected from the nozzle 70 is used to deposit the product 62 generated by the laser ablation during the laser drilling process at the next processing position. Since the product 62 is deposited at the next processing position, it contributes to the laser drilling process from the first pulse of the laser L.

[0218] In this embodiment, the first glass substrate and the second glass substrate of the technology disclosed in the present invention are both the workpiece 45 and are the same substrate. In addition, in this embodiment, the product 62 accumulated at the processing position of the laser drilling process is generated by ablation of other processing positions. Therefore, in this embodiment, the irradiation position of the laser L is also different during laser ablation and laser drilling, and the above-mentioned first irradiation condition and second irradiation condition are different.

[0219] Fig.28 The operation flow during laser drilling processing will be described. The laser processing processor 40 controls the ejection direction of the gas from the nozzle 70 by controlling the rotating stage 71 in addition to the control of each unit described in the comparative example.

[0220] exist Fig.28In the figure, reference numeral P1 indicates a processing position in the laser drilling process. Reference numeral P2 indicates a next processing position. Arrow D indicates a moving direction of the workpiece 45 by the moving stage 43 so that the target position of the laser drilling process becomes the next processing position P2. The laser processing processor 40 sets the ejection direction of the gas from the nozzle 70 to the direction opposite to the moving direction D of the workpiece 45. As a result, the product 62 generated by the laser ablation generated at the processing position P1 in the laser drilling process is accumulated at the next processing position P2.

[0221] When the laser drilling process at the processing position P1 is completed, the laser processing processor 40 moves the workpiece 45 and then performs laser drilling process at the processing position P2 where the product 62 is accumulated. The product 62 generated by the laser drilling process is further accumulated at the next processing position P2.

[0222] exist Fig.28 (A) and Fig.28 In (B), since the moving direction D of the workpiece 45 is the -Y direction, the laser processing processor 40 sets the gas ejection direction to the +Y direction. Fig.28 In (C), since the moving direction D of the workpiece 45 is the +X direction, the laser processing processor 40 sets the ejection direction of the gas to the -X direction. Fig.28 In (D), since the moving direction D of the workpiece 45 is the +Y direction, the laser processing processor 40 sets the ejection direction of the gas to the -Y direction.

[0223] 6.3 Effect

[0224] In this embodiment, the product 62 generated by laser ablation during laser drilling is deposited at the next processing position by using gas, so it is not necessary to set the laser ablation area as in the third embodiment. In addition, it is not necessary to perform laser ablation as an operation different from laser drilling, so the cumulative number of irradiation pulses for laser ablation and laser drilling can be reduced.

[0225] Fig.29 The operation flow during laser drilling processing according to the modification of the fourth embodiment will be described. Fig.29 This shows an example in which laser drilling is performed simultaneously on a plurality of processing positions arranged in the X direction. In this modification, a multi-point light shield 52 having a plurality of holes formed therein is used.

[0226] In this modified example, the nozzle 70 is provided as a plurality of nozzles, and the nozzle 70 simultaneously ejects gas to a plurality of processing positions P1 in the laser drilling process. The ejection direction of the gas is the direction opposite to the moving direction D of the workpiece 45. Thus, the products 62 generated by laser ablation generated at the plurality of processing positions P1 in the laser drilling process are deposited at the plurality of processing positions P2 in the next process.

[0227] exist Fig.29 (A) and Fig.28 In (B), since the moving direction D of the workpiece 45 is the -Y direction, the laser processing processor 40 sets the ejection direction of the gas to the +Y direction. Fig.29 The multiple processing positions P1 shown in (C) are the final processing positions.

[0228] In this way, by performing laser drilling processing on a plurality of processing positions at the same time, the productivity of the laser drilling processing is improved.

[0229] In this modification, laser drilling is performed simultaneously on processing positions arranged in a row, but the present invention is not limited thereto. For example, laser drilling may be performed simultaneously on 2×5 processing positions arranged two-dimensionally. In addition, in order to improve productivity, it is also preferred that the number of processing positions in the moving direction D of the workpiece 45 is smaller than the number of processing positions in the direction orthogonal to the moving direction D.

[0230] 7. Fifth Implementation

[0231] Next, a laser processing system 1d according to a fifth embodiment will be described. Note that the same reference numerals are given to the same configurations as those described above, and duplicate descriptions are omitted unless otherwise specified.

[0232] 7.1 Structure

[0233] Fig.30 The structure of the laser processing system 1d of the fifth embodiment is schematically shown. The structure of the laser processing device 4d of the laser processing system 1d is different from that of the laser processing system 1b of the third embodiment. In addition to the structure of the laser processing device 4b of the third embodiment, the laser processing device 4d further includes a signal line that can send the target pulse energy Et(k) of each of the multiple pulses irradiated to one processing position during laser drilling processing to the laser device 2. Here, k is a parameter for identifying the multiple pulses irradiated to one processing position.

[0234] 7.2 Action

[0235] Next, the operation of the laser processing system 1d of the fifth embodiment is described. In this embodiment, the laser ablation area is not set as in the third embodiment. In addition, in this embodiment, laser ablation, which is an operation different from laser drilling, is not performed. In this embodiment, the product 62 generated by laser ablation generated by the initial multiple pulses during laser drilling is deposited at the processing position during processing, and laser drilling is performed using the subsequent multiple pulses.

[0236] Fig.31 The relationship between the pulse fluence Fa for laser ablation and the pulse fluence Fm for laser drilling is shown. Let the number of pulses for laser ablation be Na, and let the number of pulses for laser drilling be Nm. The laser processing processor 40 sets a sufficient fluence Fa to generate laser ablation with the initial Na pulses so that the laser L is irradiated to the processing position. Therefore, it is preferred that the fluence Fa is greater than the fluence Fm.

[0237] In this embodiment, the first glass substrate and the second glass substrate of the technology disclosed in the present invention are both the workpiece 45 and are the same substrate. In addition, in this embodiment, the laser L has a different injection amount during laser ablation and laser drilling, so the first irradiation condition and the second irradiation condition are different. The pulse for laser ablation corresponds to the "first ultraviolet pulse laser" of the technology disclosed in the present invention. The pulse for laser drilling corresponds to the "second ultraviolet pulse laser" of the technology of the present invention.

[0238] Fig.32 The operation flow of the laser processing system 1d according to the fifth embodiment is schematically shown. In this embodiment, after the laser processing processor 40 sets the irradiation conditions in step S40, it performs laser ablation and laser drilling processing on each processing position in step S50.

[0239] Fig.33 The following is an operation flow for setting the irradiation conditions: First, the laser processing processor 40 determines the target pulse energy Ea for laser ablation (step S400).

[0240] The laser processing processor 40 reads the irradiation conditions for laser ablation (step S401). The target fluence Fa, the repetition frequency fa of the pulse of the laser L, and the number of irradiation pulses Na. In addition, the laser processing processor 40 reads the irradiation conditions for laser drilling (step S402). The target fluence Fm, the repetition frequency fm of the pulse of the laser L, and the number of irradiation pulses Nm are included. Here, the relationship fa=fm, Fa>Fm and Na<Nm is satisfied.

[0241] The laser processing processor 40 calculates the transmittance Ta of the attenuator 49 that makes the fluence of the laser light L on the surface 45a of the workpiece 45 the target fluence Fa (step S403). Here, the laser processing processor 40 calculates the transmittance Ta using, for example, the above formula (2).

[0242] The laser processing processor 40 calculates the pulse energy Em of the pulse for laser drilling so that the fluence of the laser light L on the surface 45a of the workpiece 45 becomes Fm (step S404). Here, the laser processing processor 40 calculates the pulse energy Em using, for example, the following equation (3).

[0243] Em=(1 / T')×Sm×(Fm / Ta)···(3)

[0244] Next, the laser processing processor 40 sets the target pulse energies Et(1) to Et(Na) of the pulses for laser ablation to the target pulse energies Ea determined in step S400 (steps S405 to S408). Then, the laser processing processor 40 sets the target pulse energies Et(Na+1) to Et(Na+Nm) of the pulses for laser drilling to the pulse energies Em calculated in step S404 (steps S409 to S411).

[0245] The attenuator 49 has a low responsiveness to changes in transmittance, so it is difficult to change the transmittance when the irradiation of the pulse for laser ablation is completed and the irradiation of the pulse for laser drilling processing is started. Therefore, in this embodiment, the transmittance of the attenuator 49 is fixed to the transmittance Ta calculated based on the fluence Fa for laser ablation, and the fluence Fm for laser drilling processing is controlled by the pulse energy Em.

[0246] Fig.34 The following is a flow chart of the operation during ablation and laser drilling. First, the laser processing processor 40 sends the data of the target pulse energy Et required for laser drilling to the laser device 2 (step S500). Here, the laser processing processor 40 sets Et=Ea and Et=Em, and sends the data of Ea and Em to the laser device 2. After receiving the data, the laser device 2 controls the chamber 21, and sends a preparation completion signal to the laser processing processor 40 when it is able to output the laser L with the target pulse energies Ea and Em.

[0247] The laser processing processor 40 determines whether a preparation completion signal is received from the laser device 2 (step S501). When the laser processing processor 40 determines that a preparation completion signal is received (step S501: Yes), the laser processing processor 40 sets the transmittance of the attenuator 49 to the transmittance Ta calculated in step S40 (step S502).

[0248] The laser processing processor 40 sets data indicating an initial processing position in the processing area of ​​the workpiece 45 (step S503). The laser processing processor 40 controls the movable stage 43 based on the set data, thereby positioning the workpiece 45 in the XY direction (step S504). In addition, the laser processing processor 40 controls the movable stage 43 in the Z direction so that the position of the transfer image of the shutter 52 is substantially consistent with the surface 45a of the workpiece 45 (step S505).

[0249] The laser processing processor 40 sends the data of the target pulse energy Et(1) to Et(Na+Nm) set in step S40 to the laser device 2 (step S506). Then, the laser processing processor 40 sends the light trigger Tr to the laser device 2 based on the repetition frequency fa and the number of irradiation pulses Na+Nm (step S507). As a result, the processing position is laser ablated using Na pulses with pulse energy Ea. Thus, after the product 62 generated by laser ablation is accumulated at the processing position, laser drilling processing is performed using Nm pulses with pulse energy Em.

[0250] The laser processing processor 40 determines whether the laser drilling processing of the processing area is completed (step S508). The completion of the laser drilling processing means that the laser drilling processing is completed at all processing positions in the processing area. When the laser processing processor 40 determines that the laser drilling processing is not completed (step S508: No), it sets data indicating the next processing position (step S509) and returns the processing to step S504.

[0251] The laser processing processor 40 repeatedly executes step S504 to step S507 until the laser drilling processing is completed. When the laser processing processor 40 determines that the laser drilling processing is completed (step S508: Yes), the processing ends.

[0252] In this embodiment, the laser ablation pulse and the laser drilling pulse are changed in the fluence. Thus, the laser L can be irradiated under irradiation conditions suitable for the product 62 generated by laser ablation to be deposited at the processing position, and the laser L can be irradiated under appropriate irradiation conditions most suitable for laser drilling.

[0253] As a result, it is possible to reduce the cumulative number of irradiation pulses and the cumulative energy of the laser light L as compared with the comparative example. This can extend the life of consumables of the laser processing system 1 d.

[0254] 8. Method for manufacturing electronic devices

[0255] The laser processing method of each of the above-described embodiments can be applied to forming a through hole in a glass substrate included in an interposer 502 in the manufacture of an electronic device 500 described below.

[0256] Fig.35 The structure of the electronic device 500 is schematically shown. Fig.35 The electronic device 500 shown has an integrated circuit chip 501, an interposer 502, and a circuit substrate 503. The integrated circuit chip 501 is, for example, a chip-shaped integrated circuit substrate on which an integrated circuit is formed on a silicon substrate. The integrated circuit chip 501 is provided with a plurality of bumps 501b electrically connected to the integrated circuit.

[0257] The interposer 502 includes an insulating glass substrate having a plurality of through holes, and a conductor electrically connecting the front and back of the glass substrate is provided in each through hole. A plurality of pads connected to the bumps 501b provided on the integrated circuit chip 501 are formed on one surface of the interposer 502, and each pad is electrically connected to any of the conductors in the through holes. A plurality of bumps 502b are provided on the other surface of the interposer 502, and each bump 502b is electrically connected to any of the conductors in the through holes.

[0258] A plurality of pads connected to the respective bumps 502b are formed on one surface of the circuit substrate 503. The circuit substrate 503 also includes a plurality of terminals electrically connected to the pads.

[0259] Fig.36 4 shows a method for manufacturing the electronic device 500. Fig.36 As shown, the manufacturing method of the electronic device 500 in this specification includes a first bonding step SP1 and a second bonding step SP2. In the first bonding step SP1, the integrated circuit chip 501 is bonded to the interposer 502. Specifically, each bump 501b of the integrated circuit chip 501 is configured on each pad of the interposer 502, and the bump 501b and the pad are electrically connected to each other. Therefore, the integrated circuit chip 501 and the interposer 502 are electrically connected to each other.

[0260] In the second bonding process SP2, the interposer 502 is bonded to the circuit substrate 503. Specifically, each bump 502b of the interposer 502 is disposed on each pad of the circuit substrate 503, and the bump 502b and the pad are electrically connected to each other. Therefore, the integrated circuit chip 501 is electrically connected to the circuit substrate 503 via the interposer 502. After the above process, the electronic device 500 is manufactured.

[0261] The above description is intended to be illustrative rather than limiting, and therefore, it is obvious to those skilled in the art that modifications may be made to the various embodiments of the present disclosure without departing from the scope of the appended claims.

[0262] The terms used in this specification and the appended claims should be interpreted as "non-limiting" terms. For example, the terms "including" or "comprising" should be interpreted as "not limited to the parts recorded as including". The term "having" should be interpreted as "not limited to the parts recorded as having". In addition, the phrase "one" recorded in this specification and the appended claims should be interpreted as "at least one" or "one or more". In addition, the terms "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 to include their combinations with contents other than "A", "B" and "C".

Claims

1. A laser processing method, wherein: The laser processing method comprises the following steps: causing a product generated from the first glass substrate by irradiating the first glass substrate with a first ultraviolet pulse laser under a first irradiation condition to accumulate at a processing position of the second glass substrate; and The hole is formed by irradiating the processing position where the product is deposited with a second ultraviolet pulse laser under a second irradiation condition different from the first irradiation condition.

2. The laser processing method according to claim 1, wherein: The first irradiation condition and the second irradiation condition include irradiation positions of the first ultraviolet pulse laser and the second ultraviolet pulse laser, The irradiation position of the first ultraviolet pulse laser is different from the irradiation position of the second ultraviolet pulse laser.

3. The laser processing method according to claim 2, wherein: The first glass substrate and the second glass substrate are different substrates.

4. The laser processing method according to claim 3, wherein: The first ultraviolet pulse laser and the second ultraviolet pulse laser are ultraviolet pulse lasers output from the same laser device. The first ultraviolet pulse laser and the second ultraviolet pulse laser are selectively irradiated onto the first glass substrate and the second glass substrate.

5. The laser processing method according to claim 2, wherein: The first glass substrate and the second glass substrate are the same substrate.

6. The laser processing method according to claim 5, wherein: The product is deposited at the processing position by irradiating the peripheral portion of the processing region including the processing position with the first ultraviolet pulse laser.

7. The laser processing method according to claim 5, wherein: By blowing gas toward the processing position, the product generated at the processing position is deposited at the next processing position.

8. The laser processing method according to claim 1, wherein: The first irradiation condition and the second irradiation condition include at least one of a fluence, a repetition frequency, a number of irradiation pulses, and a pulse width.

9. The laser processing method according to claim 8, wherein: The first glass substrate and the second glass substrate are the same substrate, The irradiation position of the first ultraviolet pulse laser is the same as the irradiation position of the second ultraviolet pulse laser. The fluence of the first ultraviolet pulse laser is greater than the fluence of the second ultraviolet pulse laser.

10. The laser processing method according to claim 1, wherein: The first glass substrate and the second glass substrate are alkali-free glass substrates.

11. The laser processing method according to claim 1, wherein: The product is a substance generated by laser ablation.

12. The laser processing method according to claim 1, wherein: The central wavelengths of the first ultraviolet pulse laser and the second ultraviolet pulse laser are the same.

13. A laser processing device comprising: an optical device that irradiates the ultraviolet pulse laser output from the laser device onto the first glass substrate and the second glass substrate; and a laser processing processor, which controls the laser device and the optical device, in, The laser processing processor causes a product generated from the first glass substrate by irradiating the first glass substrate with the ultraviolet pulse laser under a first irradiation condition to be deposited at a processing position of the second glass substrate, The laser processing processor irradiates the processing position where the product is deposited with the ultraviolet pulse laser under a second irradiation condition different from the first irradiation condition.

14. The laser processing device according to claim 13, wherein: The first glass substrate and the second glass substrate are different substrates.

15. The laser processing device according to claim 14, wherein: The laser processing device comprises: Highly reflective mirrors; and A moving mechanism moves the high reflection mirror between a position inserted into the optical path of the ultraviolet pulse laser and a position retracted from the optical path.

16. The laser processing device according to claim 15, wherein: The laser processing processor inserts the high reflection mirror into the optical path so that the ultraviolet pulse laser reflected by the high reflection mirror is irradiated onto the first glass substrate. The laser processing processor allows the ultraviolet pulse laser to irradiate the second glass substrate by retracting the high reflective mirror from the optical path.

17. The laser processing device according to claim 13, wherein: The first glass substrate and the second glass substrate are the same substrate.

18. The laser processing device according to claim 17, wherein: The laser processing device includes a nozzle for ejecting gas, The laser processing processor causes the product generated at the processing position to be deposited at a next processing position by ejecting gas from the nozzle toward the processing position.

19. A method for manufacturing an electronic device, wherein: The manufacturing method of the electronic device comprises the following steps: causing a product generated from the first glass substrate by irradiating the first glass substrate with a first ultraviolet pulse laser under a first irradiation condition to accumulate at a processing position of the second glass substrate; and forming a through hole by irradiating the processing position where the product is deposited with a second ultraviolet pulse laser under a second irradiation condition different from the first irradiation condition; bonding an interposer and an integrated circuit chip to be electrically connected to each other, the interposer having the second glass substrate and a conductor disposed in the through hole; as well as The interposer and the circuit substrate are bonded and electrically connected to each other.

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