Method for processing glass substrates and method for manufacturing electronic devices

Abstract

The present invention provides a glass substrate processing method that can form through holes while suppressing large material losses, and a method for manufacturing an electronic device using an interposer processed by this method. [Solution] The glass substrate processing method comprises the steps of: forming through holes by irradiating a glass substrate with ultraviolet wavelength pulsed laser light; forming altered areas by irradiating an ultrashort pulsed laser light surrounding the through holes and extending a predetermined range from the inner wall of the through holes; and enlarging the diameter of the through holes by etching the glass substrate with an etching solution in which the etching rate for the altered areas is faster than the etching rate for the glass substrate other than the altered areas.

Description

Technical Field

[0005] , ,

[0001] The present disclosure relates to a method for processing a glass substrate and a method for manufacturing an electronic device.

Background Art

[0002] In recent years, in semiconductor exposure apparatuses, with the miniaturization and high integration of semiconductor integrated circuits, an improvement in resolution has been demanded. For this reason, the shortening of the wavelength of light emitted from an exposure light source has been promoted. For example, as a gas laser device for exposure, a KrF excimer laser device that outputs laser light with a wavelength of about 248 nm and an ArF excimer laser device that outputs laser light with a wavelength of about 193 nm are used.

[0003] Further, since the excimer laser light has a pulse width of about several 10 ns and short wavelengths of 248 nm and 193 nm, respectively, it may be used for direct processing of polymer materials, glass materials, and the like. Chemical bonds in polymer materials can be broken by excimer laser light having photon energy higher than the bond energy. Therefore, non-thermal processing of polymer materials is possible with excimer laser light, and it is known that the processed shape becomes beautiful. Also, since glass, ceramics, etc. have a high absorption rate for excimer laser light, it is known that even materials that are difficult to process with visible and infrared laser light can be processed with excimer laser light.

Prior Art Documents

Patent Documents

[0006] Furthermore, a glass substrate processing method according to one aspect of the present disclosure may include the steps of: irradiating a glass substrate with ultrashort pulse laser light to form altered areas; irradiating with ultraviolet wavelength pulse laser light to form through holes surrounded by the altered areas; and etching the glass substrate with an etching solution in which the etching rate for the altered areas is faster than the etching rate for the non-altered areas of the glass substrate to enlarge the diameter of the through holes.

[0007] Furthermore, a method for manufacturing an electronic device according to one aspect of the present disclosure may include the steps of: forming through holes in a glass substrate by irradiating it with ultraviolet wavelength pulsed laser light; forming altered areas by surrounding the through holes and irradiating a predetermined range of area from the inner wall of the through holes with ultrashort pulsed laser light; manufacturing an interposer substrate by etching the glass substrate with an etching solution in which the etching rate for the altered areas is faster than the etching rate for the glass substrate other than the altered areas, thereby enlarging the diameter of the through holes; placing a conductor in the enlarged through holes in the interposer substrate and making an electrical connection between the two main surfaces of the interposer substrate via the conductor; coupling the interposer substrate and an integrated circuit chip to electrically connect them to each other; and coupling the interposer substrate and a circuit board to electrically connect them to each other. [Brief explanation of the drawing]

[0008] Some embodiments of this disclosure are shown below, merely as examples, with reference to the accompanying drawings. [Figure 1]Figure 1 is a schematic diagram showing an example of the overall configuration of a laser processing system in a comparative example. [Figure 2] Figure 2 is a flowchart showing the procedure for processing a glass substrate in a comparative example. [Figure 3] Figure 3 shows the process of irradiating a glass substrate with ultrashort pulse laser light. [Figure 4] Figure 4 shows a glass substrate in which a modified area has been formed. [Figure 5] Figure 5 shows the etching steps for forming through holes in a glass substrate. [Figure 6] Figure 6 shows a through-hole formed by the comparative example glass substrate processing method. [Figure 7] Figure 7 is a schematic diagram showing an example of the overall configuration of the laser processing system in Embodiment 1. [Figure 8] Figure 8 is a flowchart showing the procedure for the glass substrate processing method of Embodiment 1. [Figure 9] Figure 9 shows the process of irradiating a glass substrate with pulsed ultraviolet laser light. [Figure 10] Figure 10 shows a glass substrate in which through holes have been formed. [Figure 11] Figure 11 shows how ultrashort pulse laser light is irradiated from the inner wall of a through hole to a predetermined area. [Figure 12] Figure 12 shows a glass substrate in which a modified area has been formed in a predetermined region from the inner wall of the through hole. [Figure 13] Figure 13 shows the etching step for enlarging the diameter of the through hole in Embodiment 1. [Figure 14] Figure 14 shows the results obtained by processing the glass substrate according to Embodiment 1. [Figure 15] Figure 15 is a flowchart showing the procedure for the glass substrate processing method of Embodiment 2. [Figure 16] Figure 16 shows the process of irradiating a modified area formed on a glass substrate with pulsed ultraviolet laser light. [Figure 17] FIG. 17 is a diagram schematically showing the configuration of an electronic device. [Figure 18] FIG. 18 is a flowchart showing the procedure of the manufacturing method of the electronic device according to Embodiment 3. [Figure 19] [[ID=۸]]FIG. 19 is a diagram schematically showing a wiring formation step of arranging a conductor in an enlarged through hole in an interposer substrate. Embodiment

[0009] 1. Description of the laser processing system and glass substrate processing method of the comparative example 1.1 Configuration of the laser processing system 1.2 Description of the glass substrate processing method 1.3 Problems 2. Description of the laser processing system and glass substrate processing method of Embodiment 1 2.1 Configuration of the laser processing system 2.2 Description of the glass substrate processing method 2.3 Function and effect 3. Description of the laser processing system and glass substrate processing method of Embodiment 2 3.1 Configuration of the laser processing system 3.2 Description of the glass substrate processing method 3.3 Function and effect 4. Description of the manufacturing method of the electronic device according to Embodiment 3 4.1 Configuration 4.2 Description of the manufacturing method of the electronic device

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show some examples of the present disclosure and do not limit the content of the present disclosure. Also, not all of the configurations and operations described in each embodiment are essential as the configurations and operations of the present disclosure. In addition, the same reference numerals are assigned to the same components, and duplicate descriptions are omitted.

[0011] 1. Description of the laser processing system and glass substrate processing method of the comparative example 1.1 Configuration of the laser processing system The configuration of the comparative example laser processing system will be described below. Note that the comparative example in this disclosure is a form that the applicant recognizes as being known only to the applicant, and is not a prior art example acknowledged by the applicant.

[0012] Figure 1 is a schematic diagram showing an example of the overall configuration of a laser processing system 10 for forming through holes in a glass substrate. In this comparative example, the laser processing system 10 mainly consists of a laser beam device 100 and a laser processing device 300. In the following, the direction parallel to the optical axis of the laser beam incident on the glass substrate 20, which is the workpiece, will be described as the Z direction, the direction perpendicular to the Z direction will be described as the X direction, and the direction perpendicular to both the X and Z directions will be described as the Y direction.

[0013] The laser light device 100 mainly includes an ultrashort pulse laser light source 130, a processor 150, and a high-reflection mirror 200.

[0014] The ultrashort pulse laser light source 130 emits pulsed laser light in the 1 μm band. The 1 μm band is, for example, a wavelength range from 0.9 μm to 1.1 μm. The ultrashort pulse laser light source 130 is a system that combines a pulse compression optical unit, etc., with a YAG (Yttrium Aluminum Garnet) laser light device that emits laser light with a central wavelength of approximately 1.06 μm. The pulse width of the ultrashort pulse laser light UPL is, for example, 1 nanosecond or less. The pulse width may also be in the picosecond or femtosecond range.

[0015] The processor 150 of this disclosure is a processing unit that includes a storage device 150a in which a control program is stored and a CPU (Central Processing Unit) 150b that executes the control program. The processor 150 is specially configured or programmed to perform various processes included in this disclosure. The processor 150 also controls the entire laser processing system 10. The processor 150 is electrically connected to the laser beam device 100 and the laser processing device 300 and controls the entire laser processing system 10.

[0016] The high-reflection mirror 200 is fixed to a holder (not shown). The high-reflection mirror 200 consists of a dielectric multilayer film formed by depositing dielectric materials such as titanium oxide (TiO2) or silicon oxide (SiO2) on the surface of a transparent substrate, for example, made of synthetic quartz or calcium fluoride, to highly reflect ultrashort pulse laser light (UPL). The high-reflection mirror 200 reflects the laser light incident from the ultrashort pulse laser light source 130 to the laser processing device 300.

[0017] The laser processing apparatus 300 mainly includes an irradiation optical system 310 and a stage 370.

[0018] The irradiation optical system 310 guides the ultrashort pulse laser beam UPL emitted from the laser beam device 100 onto the glass substrate 20, and in this comparative example, guides it perpendicularly to one of the incident surfaces 20A of the glass substrate 20. The irradiation optical system 310 moves the irradiation position of the ultrashort pulse laser beam UPL in the in-plane direction of surface 20A. The irradiation optical system 310 further includes a focus position adjuster 330 that adjusts the focusing position of the ultrashort pulse laser beam UPL to move in the thickness direction of the glass substrate 20. The focus position adjuster 330 includes, for example, a diffractive optical element and a refractive focusing lens (not shown).

[0019] The stage 370 can move the glass substrate 20 in the X, Y, and Z directions by control signals from the processor 150. The stage 370 supports the glass substrate 20. The stage 370 can adjust the position of the glass substrate 20 so that the ultrashort pulse laser beam UPL emitted from the laser beam device 100 illuminates a desired position on the glass substrate 20.

[0020] The glass substrate 20 is the object to be laser-processed by irradiation with an ultrashort pulse laser beam (UPL). The thickness of the glass substrate 20 is, for example, 100 μm to 2000 μm. Examples of materials for the glass substrate 20 include alkali-free glass.

[0021] 1.2 Explanation of Glass Substrate Processing Method Next, the glass substrate processing method for the comparative example will be explained using Figures 2 to 6.

[0022] Figure 2 is a flowchart showing the procedure for the glass substrate processing method in this comparative example. As shown in Figure 2, the glass substrate processing method according to this comparative example comprises steps S1 to S2.

[0023] <Step S1> This step involves irradiating the glass substrate 20 with ultrashort pulse laser light (UPL). Figure 3 shows the process of irradiating the glass substrate 20 with ultrashort pulse laser light (UPL). As shown in Figure 3, in this step, the processor 150 controls the stage 370 to set the X and Y coordinates of the irradiation position of the ultrashort pulse laser light (UPL), and controls the laser light device 100 to irradiate the glass substrate 20 with the ultrashort pulse laser light (UPL) at the desired position.

[0024] The processor 150 controls the irradiation optical system 310 to focus the ultrashort pulse laser beam UPL to a desired position in the thickness direction of the glass substrate 20. In this comparative example, the processor 150 controls the focus position adjuster 330 to move the focusing position of the ultrashort pulse laser beam UPL in the thickness direction of the glass substrate 20, for example, from one surface 20A to the other surface 20B opposite to the first surface 20A, thereby growing the altered portion 50 in the thickness direction. Figure 4 shows the glass substrate 20 on which the altered portion 50 has been formed. In the area where the ultrashort pulse laser beam UPL has been focused and irradiated, material alteration occurs as shown in Figure 4, and a cylindrical altered portion 50 is formed. In this comparative example, the outer diameter of the altered portion 50 is 20 μm or more and 200 μm or less, but the outer diameter of the altered portion 50 may be less than 20 μm or greater than 200 μm. After this step, step S2 is performed.

[0025] <Step S2> This step involves etching the glass substrate 20 to form through-holes H. Figure 5 shows the etching step for forming through-holes H in the glass substrate 20. As shown in Figure 5, in this step, the glass substrate 20 is immersed in etching solution EL stored in container C. Etching solution EL is an etching solution in which the etching rate of the altered portion 50 formed in step S1 is faster than the etching rate of the glass substrate 20 other than the altered portion 50. Examples of etching solution EL include hydrofluoric acid or a strongly alkaline solution such as KOH. By rapidly etching the altered portion 50, through-holes H can be formed in the glass substrate 20.

[0026] 1.3 Challenges If R is the etching rate ratio ESD / ESN of the etching rate ESD of the altered portion 50 and the etching rate ESN of the glass substrate 20 other than the altered portion 50, and T is the thickness of the glass substrate 20 before processing, then the etching amount EC0 required to form a through hole H with a hole diameter d1 is expressed by the following formula (1). EC0 = (1 / 2) × T···(1)

[0027] Here, the reduction in plate thickness EL0 when etching is performed with etching amount EC0 is expressed by the following formula (2). EL0 = 2 × (1 / R) × EC0 ... (2)

[0028] For example, let's assume the plate thickness is 1000 μm, and the etching rate of the altered portion 50 is four times that of the glass substrate 20 excluding the altered portion 50. In this case, according to equations (1) and (2), regardless of the size of the hole diameter d1, the etching amount EC0 = 500 μm and the reduction in plate thickness EL0 = 250 μm. In other words, according to the glass substrate processing method shown in the comparative example, one-quarter of the glass substrate 20 is lost, resulting in significant material loss.

[0029] Figure 6 shows the through-hole H formed by the comparative example glass substrate processing method. In Figure 6, the dotted line indicates the glass substrate 20 before processing. As shown in Figure 6, the glass substrate 20 is lost by etching to form the through-hole H.

[0030] Furthermore, according to the glass substrate processing method of this comparative example, the glass substrate 20 is etched from one side 20A and the other side 20B. As a result, the diameter of the hole near the entrance of the opening of the formed through hole H is larger than that of the center of the glass substrate 20. Therefore, as shown in Figure 6, the inner wall of the formed through hole H is curved, and the hole does not have a cylindrical shape.

[0031] Therefore, the following embodiments illustrate a glass substrate processing method that can form through holes H while suppressing large material losses, and a method for manufacturing an electronic device using an interposer processed by this method.

[0032] 2. Description of the laser processing system and glass substrate processing method of Embodiment 1 Next, the laser processing system of Embodiment 1 will be described. Components similar to those described above will be denoted by the same reference numerals, and redundant descriptions will be omitted unless otherwise specified.

[0033] 2.1 Configuration of the laser processing system Figure 7 is a schematic diagram showing an example of the overall configuration of the laser processing system 10 in this embodiment. The laser processing system 10 in this embodiment differs from the comparative example laser processing system 10 in that the laser light device 100 is equipped with an ultraviolet wavelength pulsed laser light source 400, and the laser processing device 300 is equipped with an irradiation optical system 350 that focuses the ultraviolet wavelength pulsed laser light UVL. Furthermore, the stage 370 is configured to be movable so that the ultraviolet wavelength pulsed laser light UVL and ultrashort pulsed laser light UPL emitted from the laser light device 100 irradiate the glass substrate 20 at a desired position on the glass substrate 20. The processor 150 controls the stage 370 to adjust the position of the glass substrate 20 so that the ultraviolet wavelength pulsed laser light UVL and ultrashort pulsed laser light UPL emitted from the laser light device 100 irradiate the glass substrate 20 at a desired position on the glass substrate 20.

[0034] The ultraviolet wavelength pulsed laser light source 400 is a gas laser device that emits excimer laser light, such as a KrF excimer laser device with a central wavelength of approximately 246.0 nm, or an ArF excimer laser device with a central wavelength of approximately 193.4 nm. An example of the ultraviolet wavelength pulsed laser light source 400 is a YAG laser device frequency-converted to the third harmonic (wavelength approximately 355 nm) or the fourth harmonic (wavelength approximately 266 nm). The ultraviolet wavelength pulsed laser light source 400 is electrically connected to and controlled by the processor 150.

[0035] 2.2 Explanation of Glass Substrate Processing Method Next, the glass substrate processing method of Embodiment 1 will be explained using Figures 8 to 14.

[0036] Figure 8 is a flowchart showing the procedure for the glass substrate processing method in this embodiment. As shown in Figure 8, the glass substrate processing method according to this embodiment comprises steps S11 to S13.

[0037] <Step S11> This step is an ultraviolet wavelength pulsed laser light irradiation step in which ultraviolet wavelength pulsed laser light UVL is irradiated onto the glass substrate 20. Figure 9 shows the process of irradiating the glass substrate 20 with ultraviolet wavelength pulsed laser light UVL. As shown in Figure 7, in this step, the processor 150 controls the ultraviolet wavelength pulsed laser light source 400 to emit ultraviolet wavelength pulsed laser light UVL. The ultraviolet wavelength pulsed laser light UVL is incident on the irradiation optical system 350 and focused and irradiated onto a desired position on the glass substrate 20, which has been positioned by the stage 370. As a result, holes are deeply cut into the glass substrate 20 by ablation, and through holes H1 are formed in the glass substrate 20 as shown in Figure 10. In this embodiment, the diameter of the formed through holes H1 is preferably 5 μm or more and 100 μm or less. However, the diameter of the through holes H1 may be less than 5 μm or greater than 100 μm. After this step, step S12 is performed.

[0038] <Step S12> This step is an ultrashort pulse laser beam irradiation step in which an ultrashort pulse laser beam (UPL) is irradiated onto the glass substrate 20. Figure 11 shows how the ultrashort pulse laser beam (UPL) is irradiated onto a predetermined area from the inner wall of the through-hole H1, surrounding the through-hole H1. In this step, first, the processor 150 controls the stage 370 to move the glass substrate 20 from the position indicated by the dotted line in Figure 7, where ultraviolet wavelength pulse laser beam (UVL) is irradiated, to the position indicated by the solid line in Figure 7, where the ultrashort pulse laser beam (UPL) is irradiated. Next, the processor 150 controls the ultrashort pulse laser light source 130 to emit the ultrashort pulse laser beam (UPL). The ultrashort pulse laser beam (UPL) is incident on the irradiation optical system 310. The ultrashort pulse laser beam (UPL) is irradiated onto a desired position on the glass substrate 20, which has been positioned by the stage 370. At this time, the processor 150 controls the focus position adjuster 330 to focus the ultrashort pulse laser beam (UPL) onto the desired position. The processor 150 controls the focus position adjuster 330 to move the focusing position of the ultrashort pulse laser beam UPL, for example, from one surface 20A to the other surface 20B. As a result, as shown in Figure 12, the glass substrate 20 in a predetermined area surrounding the through hole H1 and extending from the inner wall of the through hole H1 is altered, and an altered portion 50 is formed. Here, if the thickness of the glass substrate 20 is T and the thickness of the altered portion 50 surrounding the through hole H1 is W, it is preferable that the following equation (3) is satisfied. W <T / 2···(3)

[0039] The processor 150 may move the focusing position of the ultrashort pulse laser beam UPL from the other surface 20B to the one surface 20A of the glass substrate 20 in the thickness direction using the focus position adjuster 330 to grow the altered portion 50 in the thickness direction, or it may change the focusing position by another predetermined process.

[0040] In the laser processing system 10 of this embodiment, the ultraviolet wavelength pulsed laser light UVL and the ultrashort pulsed laser light UPL surround the through hole H1 and irradiate a predetermined range area from the inner wall of the through hole H1. Therefore, the central axis of the through hole H1 and the central axis of the cylindrically formed altered portion 50 are approximately equal. Even if there is a misalignment between the central axis of the altered portion 50 and the central axis of the through hole H1, it is preferable that this misalignment is within, for example, 10% of the diameter of the altered portion 50 in the XY plane. In this embodiment, the outer diameter of the altered portion 50 is 20 μm or more and 200 μm or less. Therefore, it is desirable that the misalignment between the central axis of the altered portion 50 and the central axis of the through hole H1 be, for example, 2 μm or less. Note that the outer diameter of the altered portion 50 may be less than 20 μm or greater than 200 μm. After this step, step S13 is performed.

[0041] <Step S13> This step involves etching the glass substrate 20 to enlarge the diameter of the through-hole H1. Figure 13 shows the etching step for enlarging the diameter of the through-hole H1 in this embodiment. As shown in Figure 13, in this step, the glass substrate 20 is immersed in the etching solution EL stored in container C. Similar to the comparative example, the etching rate of the altered portion 50 formed in step S12 is faster than the etching rate of the glass substrate 20 other than the altered portion 50. It is preferable that the ratio R of the etching rate of the altered portion 50 to the etching rate of the glass substrate 20 other than the altered portion 50 is 2 or more. In this embodiment, the etching rate of the altered portion 50 is, for example, 4 times the etching rate of the glass substrate 20 other than the altered portion 50. Here, if the above equation (3) is satisfied, the etching time for enlarging the through-hole H1 may be shorter than in the comparative example.

[0042] Figure 14 illustrates the results of a glass substrate 20 processed by the glass substrate processing method of this embodiment. In Figure 14, the dotted line shows the glass substrate 20 before processing. In this embodiment, the inner diameter of the enlarged through-hole H is, for example, 20 μm or more and 200 μm or less. Compared with Figure 6, which shows the results of a comparative example, less glass substrate 20 is lost during etching to form the through-hole H. Also, since etching proceeds from the entire area of ​​the inner wall of the through-hole H1, the formed through-hole H is less likely to curve its inner wall and is generally cylindrical, as shown in Figure 14.

[0043] Let d2 be the diameter of the through-hole H1 formed by the ultraviolet wavelength pulsed laser light UVL. In this case, the etching amount EC1 required to enlarge the through-hole H1 to form a through-hole H with diameter d1 is shown in equation (4) below. EC1 = (1 / 2) × (d1 - d2) ... (4)

[0044] When etching is performed with etching amount EC1, the reduction in plate thickness EL1 in the glass substrate 20 is shown by the following formula (5). EL1 = 2 × (1 / R) × EC1 ... (5)

[0045] In equation (5), R represents the etching rate ratio of the etching rate ESD of the altered portion 50 to the etching rate ESN of the glass substrate 20 other than the altered portion 50, as in the comparative example. Here, for example, the thickness of the glass substrate 20 before processing is set to 1000 μm, as in the comparative example, the hole diameter d1 of the through hole H is set to 60 μm, the hole diameter d2 of the through hole H1 is set to 20 μm, and R is set to 4. Then, the etching amount EC1 is 20 μm from equation (4), and the reduction in plate thickness EL1 is 10 μm from equation (5). Since the reduction in plate thickness EL0 due to etching of the glass substrate 20 in the comparative example was 250 μm, the material loss in this embodiment is 1 / 25th compared to the comparative example. In addition, since the etching amount EC1 is reduced, there is also an effect of reducing the etching time. In the above example of this embodiment, the etching time is reduced to 1 / 25th.

[0046] 2.3 Action and Effects According to the glass substrate processing method of this embodiment, the etching solution EL can penetrate into the altered area 50 formed in a predetermined range from the inner wall of the pre-drilled through hole H1, thereby increasing the etching area and shortening the etching time required to enlarge the diameter of the through hole H1. Therefore, it is possible to suppress the large material loss that occurs due to etching to enlarge the through hole H1.

[0047] Furthermore, according to the glass substrate processing method of this embodiment, the misalignment between the central axis of the through-hole H1 formed by ultraviolet wavelength pulsed laser light UVL and the central axis of the altered portion 50 formed by ultrashort pulsed laser light UPL is within 2 μm. Therefore, unevenness in the thickness of the altered portion 50 formed in a predetermined range from the inner wall of the through-hole H1 can be suppressed. Consequently, the etching time until the hole diameter of the through-hole H1 is enlarged can be further shortened. Consequently, the reduction in the thickness of the glass substrate 20 due to etching can be further suppressed.

[0048] In this embodiment, the laser processing system 10 controls the focus position adjuster 330 to move the focusing position of the ultrashort pulse laser beam UPL in the thickness direction. However, a conical lens may be used to make the ultrashort pulse laser beam UPL a Bessel beam. A Bessel beam is non-diffracted light and propagates without spreading while remaining focused. Therefore, a cylindrical altered portion 50 can be formed on the glass substrate 20 without moving the focusing position of the ultrashort pulse laser beam UPL in the thickness direction.

[0049] 3. Description of the laser processing system and glass substrate processing method of Embodiment 2 Next, the laser processing system of Embodiment 2 will be described. Components similar to those described above will be denoted by the same reference numerals, and redundant descriptions will be omitted unless otherwise specified.

[0050] 3.1 Configuration of the laser processing system The laser processing system 10 in this embodiment is the same as in Embodiment 1 described above, so its description is omitted.

[0051] 3.2 Explanation of Glass Substrate Processing Method Next, the glass substrate processing method of Embodiment 2 will be explained using Figures 3, 4, 7, and 12 to 16.

[0052] Figure 15 is a flowchart showing the procedure for the glass substrate processing method in this embodiment. As shown in Figure 15, the glass substrate processing method according to this embodiment comprises steps S21 to S23. The flowchart in Figure 15 differs from that of Figure 8, which is the flowchart of Embodiment 1, in that the order of the ultrashort pulse laser light irradiation step and the ultraviolet wavelength pulse laser light irradiation step is reversed.

[0053] <Step S21> This step is an ultrashort pulse laser irradiation step in which an ultrashort pulse laser beam (UPL) is irradiated onto the glass substrate 20. This step is the same as step S1 of the comparative example, so the explanation is omitted. In this step, as a result of the ultrashort pulse laser irradiation, a cylindrical altered portion 50 is formed on the glass substrate 20, similar to Figure 4. In this embodiment, the outer diameter of the altered portion 50 is preferably 20 μm or more and 200 μm or less. However, the outer diameter of the altered portion 50 may be less than 20 μm or greater than 200 μm. After this step, step S22 is performed.

[0054] <Step S22> This step is an ultraviolet wavelength pulsed laser light irradiation step in which an ultraviolet wavelength pulsed laser light UVL is irradiated onto the glass substrate 20. Figure 16 shows the irradiation of the altered portion 50 formed on the glass substrate 20 with ultraviolet wavelength pulsed laser light UVL. In this step, the processor 150 controls the ultraviolet wavelength pulsed laser light source 400 to emit ultraviolet wavelength pulsed laser light UVL. The ultraviolet wavelength pulsed laser light UVL is incident on the irradiation optical system 350. The ultraviolet wavelength pulsed laser light UVL is focused and irradiated onto a desired position on the glass substrate 20, which has been positioned by the stage 370. In this embodiment, the ultraviolet wavelength pulsed laser light UVL is irradiated near the central axis of the altered portion 50 formed in a cylindrical shape on the glass substrate 20. As a result, a hole is deeply carved into the glass substrate 20 by ablation, and a through hole H1 is formed in the glass substrate 20 as shown in Figure 12. In this embodiment, the diameter of the formed through hole H1 is preferably 5 μm or more and 100 μm or less. However, the diameter of the through-hole H1 may be less than 5 μm or greater than 100 μm.

[0055] In the laser processing system 10 of this embodiment, the ultraviolet wavelength pulsed laser light UVL is irradiated near the central axis of the cylindrical altered portion 50 formed on the glass substrate 20. Therefore, the central axis of the through hole H1 and the central axis of the cylindrical altered portion 50 are approximately equal. Even if there is a misalignment between the central axis of the altered portion 50 and the central axis of the through hole H1, it is preferable that the misalignment is within, for example, 10% of the outer diameter of the altered portion 50 in the XY plane. In this embodiment, the outer diameter of the altered portion 50 is 20 μm or more and 200 μm or less. Therefore, it is desirable that the misalignment between the central axis of the altered portion 50 and the central axis of the through hole H1 be, for example, 2 μm or less. Note that the misalignment between the central axis of the altered portion 50 and the central axis of the through hole H1 may be greater than 2 μm. Also, the outer diameter of the altered portion 50 may be less than 20 μm or greater than 200 μm. After this step, step S23 is performed. In this embodiment as well, it is preferable that the above-described equation (3) is satisfied.

[0056] <Step S23> This step involves etching the glass substrate 20 to enlarge the diameter of the through-hole H1. Figure 13 shows the etching step for enlarging the diameter of the through-hole H1 in this embodiment. As shown in Figure 13, similar to step 13 of Embodiment 1, in this step the glass substrate 20 is immersed in the etching solution EL stored in container C. Similar to Embodiment 1, the etching rate of the altered portion 50 formed in step S21 is faster than the etching rate of the glass substrate 20 other than the altered portion 50. Preferably, the ratio R of the etching rate of the altered portion 50 to the etching rate of the glass substrate 20 other than the altered portion 50 is 2 or more. In this embodiment, the etching rate of the altered portion 50 is, for example, 4 times the etching rate of the glass substrate 20 other than the altered portion 50. Comparing etching in the thickness direction of the altered portion 50 with etching in the direction of enlarging the diameter of the through-hole H1, if equation (3) is satisfied, the etching time for enlarging the through-hole H1 may be shorter than in the comparative example described above.

[0057] The etching result described in step S23 above is the same as that shown in Figure 14, which illustrates the etching result of the glass substrate 20 processed by the glass substrate processing method of Embodiment 1. In Figure 14, the dotted line shows the glass substrate 20 before processing. In this embodiment, the inner diameter of the enlarged through-hole H is, for example, 20 μm to 200 μm. Compared with the results of the comparative example shown in Figure 6, less glass substrate 20 is lost during etching to enlarge the through-hole H1. Also, since etching proceeds from the entire inner wall area of ​​the through-hole H1, the enlarged through-hole H is less prone to curvature of the inner wall and is generally cylindrical, as shown in Figure 14.

[0058] 3.3 Action and Effects According to the glass substrate processing method of this embodiment, similar to Embodiment 1, the etching solution EL can penetrate into the altered area 50 formed in a predetermined range from the inner wall of the pre-drilled through hole H1, thereby increasing the etching area and shortening the etching time until a through hole H of the target diameter is formed. Therefore, it is possible to suppress the large amount of material loss caused by etching to enlarge the through hole H.

[0059] 4. Description of the manufacturing method of the electronic device of Embodiment 3 4.1 Configuration Figure 17 schematically shows the configuration of an electronic device manufactured according to this embodiment. The electronic device 500 includes an integrated circuit chip IC, an interposer substrate IP, and a circuit board CS. The integrated circuit chip IC is, for example, a chip in which an integrated circuit (not shown) is formed on a silicon substrate. The integrated circuit chip IC is provided with a plurality of bump ICBs that are electrically connected to the integrated circuit. The interposer substrate IP is an insulating glass substrate 20 in which a plurality of through holes H (not shown in Figure 17) are formed, and a conductor E is provided in each through hole H that electrically connects the front and back surfaces of the glass substrate 20. The through holes H are formed by the glass substrate processing method described in Embodiment 1 or Embodiment 2. On one surface of the interposer substrate IP, a plurality of bump ICBs, which are metal connecting protrusions, and lands (not shown), which are metal contacts connected to each bump ICB, are formed, and each land is electrically connected to one of the conductors E in the through holes H. On the other surface of the interposer substrate IP, a plurality of bump IPBs are provided, and each bump IPB is electrically connected to one of the conductors E in the through holes H. On one side of the circuit board CS, there are several lands (not shown) which are connected to metal connecting protrusions called bumps IPB. The circuit board CS is equipped with several terminals which are electrically connected to these lands.

[0060] 4.2 Description of the manufacturing method of electronic devices Next, the manufacturing method of the electronic device according to Embodiment 3 will be described with reference to Figures 17 to 19. Figure 18 is a flowchart showing the procedure for manufacturing the electronic device according to this embodiment. As shown in Figure 18, this embodiment comprises steps S31 to S34.

[0061] <Step S31> This step is a laser processing step of the interposer substrate IP manufactured from the glass substrate 20 to form through holes H in the interposer substrate IP. The through holes H are formed by the glass substrate processing method described in Embodiment 1 or Embodiment 2 above. After this step, step S32 is performed.

[0062] <Step S32> This step is a wiring formation step for an interposer substrate IP, in which a conductor E is formed in a through-hole H of the interposer substrate IP to electrically connect the two main surfaces of the interposer substrate IP. Figure 19 is a schematic diagram showing the wiring formation step in which a conductor E is placed in a through-hole H of the interposer substrate IP. In this step, for example, as shown in Figure 19, a metal, such as copper, is deposited on the inner wall of the through-hole H by electroplating using an electrolyte L, thereby electrically connecting the first main surface S1 and the second main surface S2. Of course, the conductor E may also be formed by electroless plating or other methods. Furthermore, a land is formed so as to overlap the periphery of the opening of the through-hole H into which the conductor E is embedded. The formation of the land may be performed simultaneously with the step of forming the conductor E, or it may be formed in a separate step. After this step, step S33 is performed.

[0063] <Step S33> This step is a coupling step that connects the interposer substrate IP and the integrated circuit chip IC. In this step, the bump ICB of the integrated circuit chip IC is brought into contact with the land of the interposer substrate IP, and the bump ICB and the land are electrically connected. After this step, step S34 is performed.

[0064] <Step S34> This step is a coupling step in which the interposer substrate IP and the circuit board CS are coupled. In this step, the bump IPB of the interposer substrate IP is placed on the lands of the circuit board CS, and the bump IPB and the lands are electrically connected. As a result of this step, the electronic device 500 is manufactured as shown in Figure 17.

[0065] The processor 150 may be physically configured in hardware form to perform the various processes included in this disclosure. For example, the processor 150 may be a computer including a memory storing a control program that defines the various processes, and a processing unit that executes the control program. The control program may be stored in a single memory, or it may be divided and stored in multiple physically separate memories, and the various processes may be defined by the control program as a collection of these memories. The processing unit may be a general-purpose processing unit such as a CPU, or a purpose-specific processing unit such as a GPU. The processor 150 may also be programmed in software form to perform the various processes included in this disclosure. For example, the processor 150 may have functions for performing the various processes implemented in a dedicated device such as an ASIC or a programmable device such as an FPGA. The various processes included in this disclosure may be performed by a single computer, a single dedicated device, or a single programmable device, or they may be performed by the cooperation of multiple physically separate computers, multiple dedicated devices, or multiple programmable devices. Various processes may be performed by a combination of at least two of the following: one or more computers, one or more dedicated devices, and one or more programmable devices.

[0066] The above description is intended to be illustrative, not restrictive. It will be apparent to those skilled in the art that modifications can be made to the embodiments of this disclosure without departing from the claims. It will also be apparent to those skilled in the art that the embodiments of this disclosure can be used in combination. Terms used herein and throughout the claims should be construed as "non-restrictive" unless otherwise specified. For example, terms such as "includes," "has," "equips," and "possesses" should be construed as "not excluding the existence of components other than those described." The modifier "one" should be construed as meaning "at least one" or "one or more." The term "at least one of A, B, and C" should be construed as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C," and further construed as including combinations of these with anything other than "A," "B," and "C."

Claims

1. The process involves irradiating a glass substrate with pulsed ultraviolet laser light to form through-holes, The steps include: surrounding the through-hole and irradiating a predetermined area with ultrashort pulse laser light from the inner wall of the through-hole to form a modified portion; The steps include: etching the glass substrate using an etching solution in which the etching rate of the altered portion is faster than the etching rate of the glass substrate other than the altered portion to enlarge the diameter of the through hole; Equipped with Glass substrate processing method.

2. A glass substrate processing method according to claim 1, When the thickness of the altered portion is W and the thickness of the glass substrate is T, the following equation is satisfied. W < T / 2

3. A glass substrate processing method according to claim 1, The misalignment between the central axis of the altered portion and the central axis of the through hole is 2 μm or less.

4. A glass substrate processing method according to claim 1, The aforementioned ultraviolet wavelength pulsed laser light is KrF excimer laser light.

5. A glass substrate processing method according to claim 1, The aforementioned ultrashort pulse laser light is a Bessel beam.

6. A glass substrate processing method according to claim 1, The wavelength of the aforementioned ultrashort pulse laser light is in the 1 μm range.

7. A glass substrate processing method according to claim 1, The thickness of the glass substrate is 100 μm or more and 2000 μm or less. The diameter of the through-hole formed by irradiation with the ultraviolet wavelength pulsed laser light is 5 μm or more and 100 μm or less.

8. A glass substrate processing method according to claim 1, The diameter of the enlarged through-hole is between 20 μm and 200 μm.

9. A glass substrate processing method according to claim 1, The altered portion is cylindrical in shape.

10. The process involves irradiating a glass substrate with ultrashort pulse laser light to form an altered area, The steps include irradiating the altered portion with pulsed ultraviolet laser light to form a through hole surrounded by the altered portion, The steps include: etching the glass substrate using an etching solution whose etching rate on the altered portion is faster than the etching rate on the non-altered portion of the glass substrate to enlarge the diameter of the through-hole; Equipped with Glass substrate processing method.

11. A glass substrate processing method according to claim 10, When the thickness of the altered portion after the through hole is formed is W, and the thickness of the glass substrate is T, the following equation is satisfied. W < T / 2

12. A glass substrate processing method according to claim 10, The misalignment between the central axis of the altered portion and the central axis of the through hole is 2 μm or less.

13. A glass substrate processing method according to claim 10, The aforementioned ultraviolet wavelength pulsed laser light is KrF excimer laser light.

14. A glass substrate processing method according to claim 10, The aforementioned ultrashort pulse laser light is a Bessel beam.

15. A glass substrate processing method according to claim 10, The wavelength of the aforementioned ultrashort pulse laser light is in the 1 μm range.

16. A glass substrate processing method according to claim 10, The thickness of the glass substrate is 100 μm or more and 2000 μm or less, and the diameter of the through-hole formed by irradiation with ultraviolet wavelength pulsed laser light is 5 μm or more and 100 μm or less.

17. A glass substrate processing method according to claim 10, The diameter of the enlarged through-hole is between 20 μm and 200 μm.

18. A glass substrate processing method according to claim 10, The altered portion is cylindrical before the through hole is formed.

19. The process involves irradiating a glass substrate with pulsed ultraviolet laser light to form through-holes, The steps include: surrounding the through-hole and irradiating a predetermined area with ultrashort pulse laser light from the inner wall of the through-hole to form a modified portion; The steps include: manufacturing an interposer substrate by etching the glass substrate using an etching solution in which the etching rate to the altered portion is faster than the etching rate to the glass substrate other than the altered portion, thereby enlarging the diameter of the through-holes; The steps include: placing a conductor in the through-hole in the interposer substrate, whose hole diameter has been enlarged, and making an electrical connection between the two main surfaces of the interposer substrate via the conductor; The steps include coupling the interposer substrate and the integrated circuit chip to electrically connect them to each other, The steps include: connecting the interposer board and the circuit board and electrically connecting them to each other; Equipped with A method for manufacturing electronic devices.

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