TW201736030A - Manufacturing method for glass substrate, method for forming hole in glass substrate, and apparatus for forming hole in glass substrate - Google Patents

Abstract

A manufacturing method for a glass substrate having a hole with a depth of d ([mu]m) or more includes irradiating the glass substrate with a laser beam emitted from a CO2 laser oscillator for an irradiation time t ([mu]sec), to form a hole in the glass substrate. The laser beam is delivered to the glass substrate after being condensed at a focusing lens. A power density Pd(W/cm2), defined by Pd= P0/S, where P0 and S are a power and a beam cross-sectional area of the laser beam just prior to entering the focusing lens, respectively, is 600 W/cm2 or less. The irradiation time t ([mu]sec) satisfies t ≥ 10*d/ (Pd)<SP>1/2</SP>.

Description

Method for producing glass substrate, method for forming hole in glass substrate, and device for forming hole in glass substrate

The present invention relates to a method for producing a glass substrate, a method for forming a hole in a glass substrate, and a device for forming a hole in a glass substrate.

From the prior art, a technique of forming fine holes in a glass substrate by irradiating a laser beam from a laser oscillator to a glass substrate has been known. For example, Patent Document 1 describes a laser processing machine for glass micropore processing including a pulsed CO ₂ laser oscillator and various optical systems including a condensing lens. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2013-241301

[Problem to be Solved by the Invention] In the laser processing machine for glass micropore processing described in Patent Document 1, a pulsed CO ₂ laser beam emitted from a pulsed CO ₂ laser oscillator is irradiated onto a glass substrate. . By irradiation of the CO ₂ laser beam, the glass substrate is locally heated to form fine pores at the irradiation position. Here, in such prior hole processing techniques, there is a case where cracks are generated on the glass substrate during the hole processing or after the hole processing. Thus, at the time of hole machining is actually performed, in order to shorten the irradiation time as the CO ₂ laser beam (i.e., the pulsed CO ₂ laser beam widths) of the adjustment mode. However, if the irradiation time of the CO ₂ laser beam is shortened, it will be difficult to form a sufficiently deep hole in the glass substrate this time. Therefore, in the case where it is necessary to form a deeper hole, it is necessary to increase the peak power of the pulsed CO ₂ laser beam as much as possible. However, if the peak power of the CO ₂ laser beam is increased, the impact applied to the glass substrate at the time of irradiation will become large, and eventually, as a result of cracking on the glass substrate. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for producing a glass substrate having pores having a desired depth which can effectively suppress the occurrence of cracks. Further, it is an object of the present invention to provide a method for effectively suppressing the occurrence of cracks and forming a hole having a desired depth on a glass substrate. Further, an object of the present invention is to provide an apparatus which can effectively suppress the occurrence of cracks and form a hole having a desired depth on a glass substrate. [Technical means for solving the problem] In the present invention, there is provided a method for producing a glass substrate, wherein the glass substrate has a hole having a depth of d (μm) or more, and the manufacturing method includes a thunder which is oscillated by a CO ₂ laser oscillator a step of irradiating the glass beam to the glass substrate at a time of irradiation time t (μsec) to form a hole in the glass substrate, wherein the laser beam is condensed by the condensing lens and then irradiated onto the glass substrate, and is incident on the glass substrate When the power of the laser beam and the cross-sectional area of the beam before the condensing lens are P ₀ and S, respectively, the power density P _d (W/cm ² ) expressed by the following formula (1) is 600 W/cm ² or less. : P _d = P ₀ / S (1) Formula; and the above irradiation time t (μsec) satisfies the following formula (2): t≧10×d/(P _d ) ^1/2 (2). Moreover, in the present invention, there is provided a method of forming a hole in a glass substrate, wherein the hole has a depth d (μm) or more, the method comprising irradiating a laser beam oscillated by a CO ₂ laser oscillator with an irradiation time t ( a step of irradiating the glass substrate to the glass substrate at a time of μsec), wherein the laser beam is condensed by the condensing lens and then irradiated onto the glass substrate to be incident on the ray immediately before entering the condensing lens When the power of the beam and the cross-sectional area of the beam are set to P ₀ and S, respectively, the power density P _d (W/cm ² ) expressed by the following formula (1) is 600 W/cm ² or less: P _d = P ₀ / S (1) Formula; and the above irradiation time t (μsec) satisfies the following formula (2): t≧10×d/(P _d ) ^1/2 (2). Further, in the present invention, there is provided an apparatus for forming a hole in a glass substrate, wherein the hole has a depth d (μm) or more, the device comprising: a CO ₂ laser oscillator oscillating a laser beam; and a collecting lens, And concentrating the laser beam onto the glass substrate; the device forms a hole in the glass substrate by irradiating the laser beam to the glass substrate for a time of irradiation time t (μsec), and is about to enter the above-mentioned poly When the power of the laser beam and the cross-sectional area of the beam before the optical lens are P ₀ and S, respectively, the power density P _d (W/cm ² ) expressed by the following formula (1) is 600 W/cm ² or less: P _d = P ₀ / S (1) Formula; and the above irradiation time t (μsec) satisfies the following formula (2): t ≧ 10 × d / (P _d ) ^1/2 (2). [Effect of the Invention] In the present invention, a method for producing a glass substrate having a hole having a desired depth which can effectively suppress the occurrence of cracks can be provided. Further, in the present invention, it is possible to provide a method for effectively suppressing the occurrence of cracks and forming a hole having a desired depth on a glass substrate. Further, in the present invention, it is possible to provide a device which can effectively suppress the occurrence of cracks and form a hole having a desired depth on a glass substrate.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (Manufacturing Method of Glass Substrate According to One Embodiment of the Present Invention) In one embodiment of the present invention, a method for producing a glass substrate having a hole having a desired depth of d (μm) or more is provided (hereinafter referred to as "first manufacturing"method"). The first manufacturing method includes the steps of: irradiating a laser beam oscillated by a CO ₂ laser oscillator to a glass substrate at a time of irradiation time t (μsec) or more, and forming a desired depth d (μm) on the glass substrate. The above holes. Hereinafter, the first manufacturing method will be described in detail with reference to Fig. 1 . (Hole Forming Apparatus) FIG. 1 schematically shows a configuration of a hole forming apparatus (hereinafter referred to as a "first hole forming apparatus") which can be used in carrying out the first manufacturing method. As shown in FIG. 1, the first hole forming apparatus 100 includes a laser oscillator 110, various optical systems, and a stage 160. In the example shown in FIG. 1, the optical system is provided with a beam amplifier 120, a wave plate 130, a diaphragm 140, and a collecting lens 150 in this order from the side of the laser oscillator 110. However, the arrangement of the optical system is only an example, and optical members other than the condensing lens 150 may be omitted. The laser oscillator 110 is a CO ₂ laser oscillator that can illuminate the CO ₂ laser beam 113 toward the beam amplifier 120. The laser oscillator 110 can be a pulsed CO ₂ laser oscillator or a continuous wave CO ₂ laser oscillator. In the former case, a pulsed CO ₂ laser beam is emitted from the laser oscillator 110, and in the latter case, a continuous wave CO ₂ laser beam is emitted from the laser oscillator 110. The wavelength of the CO ₂ laser beam (hereinafter simply referred to as "laser beam") 113 can be, for example, in the range of 9.2 μm to 9.8 μm. The diameter of the laser beam 113 in this range is _{1. The} cross-sectional area of the beam is S ₁ . The beam amplifier 120 has a function of amplifying the laser beam 113 irradiated from the laser oscillator 110 at a specific ratio. For example, in the example shown in Figure 1, the beam amplifier 120 will have a diameter of ₁ and the incident laser beam 113 having a beam cross-sectional area of S ₁ is enlarged to a diameter of ₂ and the beam cross-sectional area is the laser beam 123 of S ₂ . Here, ₁ < ₂ and S ₁ <S ₂ . The magnification ratio is, for example, in the range of 1.5 times to 4.0 times. The wavelength plate 130 is disposed on the opposite side of the laser oscillator 110 via the beam amplifier 120. The wave plate 130 is composed of, for example, a quarter-wave plate or the like. When the laser beam 123 is linearly polarized, the wavelength plate 130 converts the laser beam into a circularly polarized laser beam. Hereinafter, the laser beam emitted from the wavelength plate 130 is referred to as "laser beam 133". Furthermore, the quality of the hole formed in the glass substrate (for example, the verticality and the true circle of the hole) is the case where the laser beam irradiated to the glass substrate is converted into circularly polarized light compared to the case of the laser beam irradiated with the linearly polarized light. Degree, etc.) improve. The aperture 140 is disposed on the opposite side of the laser oscillator via the wavelength plate 130. The aperture 140 has the function of adjusting the incident laser beam 133 to a specific shape. For example, in the example shown in Figure 1, the aperture 140 will have a diameter of ₂ and the incident laser beam 133 having a beam cross-sectional area of S ₂ is adjusted to have a diameter of ₃ is a cross-sectional area S ₃ and the beam 143 of the laser beam. Here, ₃ < ₂ and S ₃ <S ₂ . The condenser lens 150 is disposed on the opposite side of the laser oscillator via the aperture 140. As shown in FIG. 1, the condensing lens 150 has a function of condensing the incident laser beam 143 to a specific position of the glass substrate 190 which is a member to be processed. The stage 160 has a function of supporting the glass substrate 190. The stage 160 can be a stage that can move in the XY direction. Further, as described above, at least one of the beam amplifier 120, the wave plate 130, and the diaphragm 140 may be omitted. When the first hole forming apparatus 100 having such a configuration forms a hole in the glass substrate 190, the glass substrate 190 is first placed on the stage 160. The glass substrate 190 has a first surface 192 and a second surface 194 that face each other. The glass substrate 190 is disposed on the stage 160 such that the side of the second surface 194 is on the side of the stage 160. Furthermore, the stage 160 may have a device for fixing the glass substrate 190. For example, the stage 160 may have a suction mechanism to suction and fix the glass substrate 190 to the stage 160. By using such a stage 160, the positional shift of the glass substrate 190 during processing can be suppressed. The laser beam 113 is then illuminated from the laser oscillator 110 towards the beam amplifier 120. The laser beam 113 irradiated to the beam amplifier 120 is amplified by the beam amplifier 120 to become an amplified laser beam 123, and the amplified laser beam 123 is irradiated to the wavelength plate 130. The amplified laser beam 123 irradiated to the wavelength plate 130 is converted into circularly polarized light by the wavelength plate 130, and the circularly polarized laser beam 133 is irradiated to the aperture 140. The circularly polarized laser beam 133 irradiated to the aperture 140 is shaped in the aperture 140 to become the laser beam 143. Thereafter, the laser beam 143 formed by the aperture 140 is irradiated to the collecting lens 150. The laser beam 143 is focused by the condenser lens 150 to become a focused laser beam 153 having a desired shape and is incident on the illumination position 196 of the glass substrate 190. By focusing the laser beam 153, the temperature of the irradiation position 196 of the glass substrate 190 and the portion immediately below it rises, so that the substance present in the region is removed. Thereby, the hole 198 is formed at the irradiation position 196 of the glass substrate 190. Furthermore, as shown in FIG. 1, the hole 198 formed in the glass substrate 190 may be a through hole. Alternatively, the aperture 198 can also be a non-through hole. Thereafter, the stage 160 is moved in the XY plane and the same operation is performed, whereby a plurality of holes 198 can be formed in the glass substrate 190. Here, the first manufacturing method is characterized in that the power of the laser beam 143 immediately before entering the condensing lens 150 is P ₀ (W), and the laser beam 143 immediately before the condensing lens 150 is incident. When the beam area is set to S ₃ , the power density P _d (W/cm ² ) of the laser beam 143 represented by the following formula (3) is 600 W/cm ² or less: P _d = P ₀ / S ₃ ( 3). The power density P _d (W/cm ² ) is preferably 320 W/cm ² or less, more preferably 160 W/cm ² or less, and particularly preferably 80 W/cm ² or less. Further, in order to advance the hole processing, the power density P _d (W/cm ² ) is preferably 5 W/cm ² or more, and more preferably 10 W/cm ² or more. In the first manufacturing method, when the depth of the hole formed in the glass substrate 190 is set to d (μm) or more, the irradiation laser beam 153 irradiates the glass substrate 190, that is, the irradiation time t (μsec). The following formula (4) is satisfied: t≧10×d/(P _d ) ^1/2 (4). Here, P _d is the above power density P _d (W/cm ² ). For example, in the case of forming a hole having a depth d=50 μm or more in the glass substrate 190 in the first manufacturing method, if the right side of the formula (4) is t _min (hereinafter referred to as “minimum irradiation time”), Then, when the depth d=50 μm and the power density P _d (W/cm ² )=600 W/cm ² , the minimum irradiation time becomes t _min ≒20 μsec. Therefore, in this case, the time t at which the focused laser beam 153 irradiates the glass substrate 190 is selected so as to be 20 μsec or more. Further, for example, when a hole having a depth d=100 μm or more is formed on the glass substrate 190, the minimum irradiation time becomes t _min when the depth d=100 μm and the power density P _d (W/cm ² )=600 W/cm ² ≒41 μsec. Therefore, in this case, the time t at which the focused laser beam 153 irradiates the glass substrate 190 is selected so as to be 41 μsec or more. In this manner, in the first manufacturing method, the irradiation is about 143 to the power density of the laser beam before the converging lens 150 P _d (W / cm ²⁾ can be sufficiently suppressed to ² or less, for example, 600 W / cm. Therefore, the impact caused by the focused laser beam 153 irradiated onto the glass substrate 190 can be sufficiently reduced, and the occurrence of cracks on the glass substrate 190 can be effectively suppressed. Further, the focused laser beam 153 illuminates the glass substrate 190 for a sufficiently long period of time. Therefore, even if the power density P _d (W/cm ² ) is relatively small, a hole having a desired depth d or more can be formed on the glass substrate 190. According to the above-described effects, in the first manufacturing method, the hole 198 having a depth of a desired depth d or more can be formed in a state in which the occurrence of cracks is effectively suppressed. Further, in the first manufacturing method, since the power density P _d (W/cm ² ) can be made relatively small, cracking can be prevented even if the irradiation is performed for a long period of time. (Laser Oscillator 110) As described above, the first hole forming device has a CO ₂ laser oscillator 110, which may be a continuous wave CO ₂ laser oscillator or a pulsed CO ₂ laser. Oscillator. Among them, the continuous wave CO ₂ laser oscillator can oscillate a continuous wave CO ₂ laser beam. In Fig. 2, an example of an output waveform of a laser beam oscillated by a continuous wave CO ₂ laser oscillator is schematically shown. In Fig. 2, the horizontal axis is time T (sec), and the vertical axis is the power of the laser beam. Further, the vertical axis is expressed by dividing the power of the laser beam by the power density (W/cm ² ) obtained by the beam cross-sectional area S of the laser beam. However, the vertical axis is the same as the power of the laser beam. As shown in FIG. 2, the laser beam 212 oscillated by the continuous wave CO ₂ laser oscillator has a flat output waveform that does not substantially change with respect to time T. Thus, the power density of the laser beam 212, time-averaged, i.e. average power density (expressed as P _ave) (represented by P _max) and a peak power density of the laser beam 212 are substantially equal. On the other hand, a pulsed CO ₂ laser oscillator can oscillate a pulsed CO ₂ laser beam. In Fig. 3, an example of an output waveform of a laser beam oscillated by a pulsed CO ₂ laser oscillator is schematically shown. In Fig. 3, the horizontal axis and the vertical axis are the same as those in Fig. 2. As shown in FIG. 3, the laser beam 214 oscillated by the pulsed CO ₂ laser oscillator has a pulsed output waveform. Thus, the average power density (indicated by _Pave ) of the laser beam 214 is a different value than the peak power density (in _Pmax ) of the laser beam 214. Thus, in the laser beam 212 oscillated by the continuous wave CO ₂ laser oscillator, P _ave = P _max , and in contrast, in the laser beam 214 oscillated by the pulsed CO ₂ laser oscillator , P _ave ≠ P _max . In the present application, it should be noted that the power density P _d (W/cm ² ) of the laser beam 143 represented by the above formula (3) means the maximum power of the output waveform, that is, P _max . Therefore, in the case where the laser oscillator 110 is a continuous wave CO ₂ laser oscillator, the power density P _d (W/cm ² ) of the laser beam 143 is substantially equal to its average power density, but in the laser oscillator In the case where 110 is a pulsed CO ₂ laser oscillator, the power density P _d (W/cm ² ) of the laser beam 143 is expressed as a value different from its average power density. Further, for example, when the focused laser beam 153 has a continuous wave as shown in FIG. 2, the irradiation time t (μsec) in the above formula (4) means that the focused laser beam 153 actually illuminates the glass substrate 190. Total time. On the other hand, when the focused laser beam 153 has a pulse-like output waveform as shown in FIG. 3, the irradiation time t (μsec) means that the focused laser beam 153 actually means that the focused laser beam 153 is actually shorter than the irradiation time t. The total time for irradiating the glass substrate 190, but when the irradiation time t is longer than the pulse width, the time during which the non-oscillation time between pulses is included is also included. Hereinabove, a method of manufacturing a glass substrate and an apparatus for forming a hole in a glass substrate according to an embodiment of the present invention have been described with reference to Figs. 1 to 3 . However, the above description is only an example, and the present invention may be embodied in other forms. For example, the present invention is also applicable to a method of forming a non-through hole in a glass substrate. [Embodiment] Next, an embodiment of the present invention will be described. In the following description, Examples 1 to 6 are Examples, and Examples 7 to 12 are Comparative Examples. (Example 1) A glass substrate containing a hole was produced by forming a hole in a glass substrate using the first hole forming device shown in Fig. 1 described above. Further, in the obtained glass substrate, the presence or absence of cracks and the depth (penetration/non-penetration) of the pores were evaluated. The depth of the holes was evaluated in the following manner. The depth d of the desired hole is set to the thickness of the glass substrate. When the hole formed in the glass substrate penetrates, it is determined that the required depth d is obtained, and if it is not penetrated, it is determined that the desired depth d is not obtained. In the first hole forming apparatus, a continuous wave CO ₂ laser oscillator (DIAMOND-GEM100L-9.6: manufactured by Coherent) was used as the laser oscillator. Use this continuous wave CO ₂ laser oscillator to make the beam diameter A continuous wave CO ₂ laser beam with ₁ = 3.5 mm oscillates. Beam diameter of the continuous wave CO ₂ laser beam using a beam amplifier _{1 is} enlarged to 3.5 times (hence, beam diameter) ₂ = 3.5 mm × 3.5 = 12.25 mm). Also, a λ/4 wavelength plate was used as the wavelength plate. As for the aperture, the beam diameter of the laser beam is used after passing through the aperture. ₃ becomes 9 mm. An aspherical lens with a focal length of 25 mm was used as a collecting lens. Furthermore, between the aperture and the concentrating lens, the peak power (= average power) of the laser beam is 50 W. Thus, the power density of the laser beam of the location P _d of about 79 W / cm ^2. A 50 mm x 50 mm alkali-free glass was used as the glass substrate. The thickness of the glass substrate was set to 100 μm. Therefore, in Example 1, the depth d of the desired hole was 100 μm. The irradiation time t at which the laser beam is irradiated onto the glass substrate is set to 120 μsec. Here, in Example 1, the minimum irradiation time corresponding to the right side of the above equation (4) becomes t _min of about 113 μsec. Therefore, the minimum irradiation time t _min < irradiation time t. The number of holes formed in the glass substrate was set to 10,000. The glass substrate after the formation of the pores was observed, and as a result, no abnormality such as cracks was observed on the glass substrate. Also, the hole penetrates. (Example 2) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 1. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this Example 2, the thickness of the glass substrate was set to 300 μm. Therefore, the depth d of the hole required is 300 μm. Further, the irradiation time t was set to 380 μsec. Here, in Example 2, the right side corresponds to the minimum irradiation time of the above-described (4) of formula t _min becomes about 338 μsec. Therefore, the minimum irradiation time t _min < irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, no abnormality such as cracks was observed on the glass substrate. Also, the hole penetrates. (Example 3) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 1. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this example 3, the peak power (=average power) of the laser beam is set to 100 W between the aperture and the condensing lens. Thus, the power density of the laser beam of the location P _d of about 157 W / cm ^2. Further, the irradiation time t was set to 80 μsec. Here, in Example 3, the right side corresponds to the minimum irradiation time of the above equation (4) becomes t _min of about 80 μsec. Therefore, the minimum irradiation time t _min = the irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, no abnormality such as cracks was observed on the glass substrate. Also, the hole penetrates. (Example 4) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 3. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this Example 4, the thickness of the glass substrate was set to 300 μm. Therefore, the depth d of the hole required is 300 μm. Further, the irradiation time t was set to 260 μsec. Here, in Example 4, the minimum exposure time corresponding to the right side of the above equation (4) becomes t _min of about 239 μsec. Therefore, the minimum irradiation time t _min < irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, no abnormality such as cracks was observed on the glass substrate. Also, the hole penetrates. (Example 5) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 1. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this example 5, a pulsed CO ₂ laser oscillator (manufactured by Coherent) was used as the laser oscillator. Use this pulsed CO ₂ laser oscillator to make the beam diameter A pulsed CO ₂ laser beam of ₁ = 3.5 mm oscillates. Further, between the aperture and the condensing lens, the average power of the laser beam was set to 67 W, and the peak power of the laser beam was set to 201 W. Thus, the power density of the laser beam between the condenser lens and the aperture P _d of about 316 W / cm ^2. Further, the irradiation time t was set to 56 μsec. Here, in Example 5, the right side corresponds to the minimum irradiation time of the above equation (4) becomes t _min of about 56 μsec. Therefore, the minimum irradiation time t _min = the irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, no abnormality such as cracks was observed on the glass substrate. Also, the hole penetrates. (Example 6) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 5. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this example 6, the thickness of the glass substrate was set to 300 μm. Therefore, the depth d of the hole required is 300 μm. Further, the irradiation time t was set to 170 μsec. Here, in Example 6, the right side corresponds to the minimum irradiation time of the above-described (4) of formula t _min is approximately 169 μsec. Therefore, the minimum irradiation time t _min < irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, no abnormality such as cracks was observed on the glass substrate. Also, the hole penetrates. (Example 7) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 5. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this example 7, between the aperture and the condensing lens, the average power of the laser beam is set to 130 W, and the peak power of the laser beam is set to 390 W. Thus, the power density of the laser beam between the condenser lens and the aperture P _d of about 613 W / cm ^2. Moreover, the irradiation time t of the glass substrate was set to 41 μsec. Here, in Example 7, the right side corresponds to the minimum irradiation time of the above equation (4) becomes t _min of about 40 μsec. Therefore, the minimum irradiation time t _min < irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, it was confirmed that cracks occurred on the glass substrate. The rate of cracking per 10,000 holes was 2%. The hole penetrates. (Example 8) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 7. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this Example 8, the thickness of the glass substrate was set to 300 μm. Therefore, the depth d of the hole required is 300 μm. Further, the irradiation time t was set to 122 μsec. Here, in Example 8, the right side corresponds to the minimum irradiation time of the above-described (4) of formula t _min becomes about 121 μsec. Therefore, the minimum irradiation time t _min < irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, it was confirmed that cracks occurred on the glass substrate. The crack rate per 10,000 holes was 5%. The hole penetrates. (Example 9) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 5. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this example 9, between the aperture and the condensing lens, the average power of the laser beam is set to 400 W, and the peak power of the laser beam is set to 1200 W. Thus, the power density of the laser beam between the condenser lens and the aperture P _d is about 1886 W / cm ^2. Further, the irradiation time t was set to 23 μsec. Here, in Example 9, the right side corresponds to the minimum irradiation time of the above equation (4) becomes t _min of about 23 μsec. Therefore, the minimum irradiation time t _min = the irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, it was confirmed that cracks occurred on the glass substrate. The rate of cracking per 10,000 holes is 50%. The hole penetrates. (Example 10) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 9. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. However, in this Example 10, the thickness of the glass substrate was set to 300 μm. Therefore, the required hole depth is 300 μm. Further, the irradiation time t was set to 72 μsec. Here, in Example 10, the right side corresponds to the minimum irradiation time of the above equation (4) becomes t _min of about 69 μsec. Therefore, the minimum irradiation time t _min < irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, it was confirmed that cracks occurred on the glass substrate. The rate of cracking per 10,000 holes was 80%. The hole penetrates. (Example 11) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 1. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. The irradiation time t was set to 30 μsec. Here, in Example 11, the right side corresponds to the minimum irradiation time of the above-described (4) of formula t _min becomes about 113 μsec. Therefore, the minimum irradiation time t _min > irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, no abnormality such as cracks was observed on the glass substrate. However, since the minimum irradiation time t _min > irradiation time t, the hole of the desired depth could not be obtained, and the hole was not penetrated. (Example 12) A glass substrate containing a hole was produced by forming a hole in a glass substrate in the same manner as in Example 10. Further, in the obtained glass substrate, the presence or absence of cracks and the depth of the pores were evaluated. The irradiation time t was set to 35 μsec. Here, in Example 12, the right side corresponds to the minimum irradiation time of the above equation (4) becomes t _min of about 69 μsec. Therefore, the minimum irradiation time t _min > irradiation time t. The glass substrate after the formation of the pores was observed, and as a result, it was confirmed that cracks occurred on the glass substrate. The rate of cracking per 10,000 holes was 40%. Further, since the minimum irradiation time t _min > the irradiation time t, the hole of the desired depth is not obtained, and the hole is not penetrated. In Table 1 below, a method for producing a glass substrate containing pores in each example and evaluation results are collectively shown. [Table 1] As shown in Table 1, it was confirmed that by using the method for producing a glass substrate containing pores as shown in Examples 1 to 6, the occurrence of cracks can be effectively suppressed, and pores having a desired depth can be formed.

100‧‧‧ hole forming device
110‧‧‧Laser Oscillator
113‧‧‧Laser beam
120‧‧‧ Beam Amplifier
123‧‧‧Laser beam
130‧‧‧wavelength board
133‧‧‧Laser beam
140‧‧‧ aperture
143‧‧‧Laser beam
150‧‧‧ Concentrating lens
153‧‧‧ Focused laser beam
160‧‧‧ stage
190‧‧‧ glass substrate
192‧‧‧ first surface
194‧‧‧ second surface
196‧‧‧ Irradiation position
198‧‧‧through holes
212‧‧‧Laser beam
214‧‧‧Laser beam
S ₁ ‧‧‧beam cross-sectional area
S ₂ ‧‧‧beam cross-sectional area
S ₃ ‧‧‧beam cross-sectional area
₁ ‧‧‧diameter
₂ ‧‧‧diameter
₃ ‧‧‧diameter

Fig. 1 is a view schematically showing the configuration of a hole forming device according to an embodiment of the present invention. Fig. 2 is a view schematically showing an example of an output waveform of a laser beam oscillated by a continuous wave CO ₂ laser oscillator. Fig. 3 is a view schematically showing an example of an output waveform of a laser beam oscillated by a pulsed CO ₂ laser oscillator.

100‧‧‧ hole forming device

110‧‧‧Laser Oscillator

113‧‧‧Laser beam

120‧‧‧ Beam Amplifier

123‧‧‧Laser beam

130‧‧‧wavelength board

133‧‧‧Laser beam

140‧‧‧ aperture

143‧‧‧Laser beam

150‧‧‧ Concentrating lens

153‧‧‧ Focused laser beam

160‧‧‧ stage

190‧‧‧ glass substrate

192‧‧‧ first surface

194‧‧‧ second surface

196‧‧‧ Irradiation position

198‧‧‧through holes

S ₁ ‧‧‧beam cross-sectional area

S ₂ ‧‧‧beam cross-sectional area

S ₃ ‧‧‧beam cross-sectional area

‧‧‧diameter

‧‧‧diameter

‧‧‧diameter

Claims (16)

A method for manufacturing a glass substrate, wherein the glass substrate has a hole having a depth of d (μm) or more, the manufacturing method comprising irradiating a laser beam oscillated by a CO ₂ laser oscillator at a time of irradiation time t (μsec) to a step of forming a hole in the glass substrate on the glass substrate, wherein the laser beam is condensed by the condensing lens and then irradiated onto the glass substrate, and the power and the beam of the laser beam immediately before entering the condensing lens When the cross-sectional area is P ₀ and S, respectively, the power density P _d (W/cm ² ) expressed by the following formula (1) is 600 W/cm ² or less: P _d = P ₀ /S (1); Further, the irradiation time t (μsec) satisfies the following formula (2): t≧10×d/(P _d ) ^1/2 (2). The manufacturing method of claim 1, wherein the CO ₂ laser oscillator is a continuous wave CO ₂ laser oscillator. The manufacturing method of claim 1, wherein the CO ₂ laser oscillator is a pulsed CO ₂ laser oscillator. The manufacturing method of claim 1, wherein the wavelength of the laser beam oscillated by the CO ₂ laser oscillator is in a range of 9.2 μm to 9.8 μm. The manufacturing method according to any one of claims 1 to 3, wherein the hole is a through hole. A method for forming a hole in a glass substrate, wherein the hole has a depth d (μm) or more, the method comprising irradiating a laser beam oscillated by a CO ₂ laser oscillator to a glass substrate at a time of irradiation time t (μsec) In the step of forming a hole in the glass substrate, the laser beam is condensed by the condensing lens and then irradiated to the glass substrate, and the power and beam cross-sectional area of the laser beam immediately before being incident on the condensing lens When P ₀ and S are respectively set, the power density P _d (W/cm ² ) expressed by the following formula (1) is 600 W/cm ² or less: P _d = P ₀ /S (1); The irradiation time t (μsec) satisfies the following formula (2): t≧10×d/(P _d ) ^1/2 (2). The method of claim 6, wherein the CO ₂ laser oscillator is a continuous wave CO ₂ laser oscillator. The method of claim 6, wherein the CO ₂ laser oscillator is a pulsed CO ₂ laser oscillator. The method of any one of claims 6 to 8, wherein the holes are through holes. A device for forming a hole in a glass substrate, wherein the hole has a depth d (μm) or more, the device includes: a CO ₂ laser oscillator that oscillates a laser beam; and a collecting lens that condenses the laser beam To the glass substrate; the device forms a hole in the glass substrate by irradiating the laser beam to the glass substrate at a time of irradiation time t (μsec), and the laser beam is to be incident on the laser beam immediately before the concentrating lens When the power and the beam cross-sectional area are respectively P ₀ and S, the power density P _d (W/cm ² ) expressed by the following formula (1) is 600 W/cm ² or less: P _d = P ₀ /S ( 1) Formula; and the above irradiation time t (μsec) satisfies the following formula (2): t≧10×d/(P _d ) ^1/2 (2). The apparatus of claim 10 wherein said CO ₂ laser oscillator is a continuous wave CO ₂ laser oscillator. The apparatus of claim 10 wherein said CO ₂ laser oscillator is a pulsed CO ₂ laser oscillator. The apparatus of any one of claims 10 to 12, wherein said laser beam has a wavelength in the range of 9.2 μm to 9.8 μm. The apparatus according to any one of claims 10 to 13, further comprising an aperture for adjusting a cross-sectional area of the beam of the laser beam between the CO ₂ laser oscillator and the condensing lens. The device of claim 14, further comprising a λ/4 wavelength plate between the CO ₂ laser oscillator and the aperture. The device of any one of claims 10 to 15, wherein the hole is a through hole.