TW202030164A - Microstructured glass substrate and method for manufacturing microstructured glass substrate - Google Patents

Abstract

A microstructured glass substrate (10) has a thickness of 50-2000 [mu]m, is opened in a first main surface (11) and has a hole which, when the microstructured glass substrate (10) is referred to as t, satisfies the following requirements: (i) 0.4 ≤ [Phi]C/[Phi]A ≤ 1.0; (ii) 70 DEG ≤ [Theta] ≤ 90 DEG; (iii)Ra ≤ 1.0 [mu]m; (iv) 0 ≤ D/t ≤ 0.003; and (v) 1.5 ≤ L/[Phi]C ≤ 30.

Description

Glass substrate with fine structure and manufacturing method of glass substrate with fine structure

The present invention relates to a method for manufacturing a glass substrate with a fine structure and a glass substrate with a fine structure.

In recent years, glass substrates have attracted attention as materials for semiconductor packaging substrates. The reason is that the glass substrate has favorable characteristics from the viewpoints of thermal stability, matching with the linear expansion coefficient of semiconductors, and high-frequency low-loss electrical characteristics. In order to use a glass substrate as a substrate for semiconductor packaging, a technique of forming a microstructure such as a hole in the glass substrate is proposed. On the other hand, since glass is a brittle material, it is difficult to use a mechanical drill to form a fine structure on a glass substrate. Moreover, in the case of processing glass substrates using a laser drilling device, the tact time becomes longer. In this regard, as a practical method for forming a fine structure on a glass substrate, a combination of laser irradiation to the glass substrate for forming the deteriorated portion and wet etching for removing the deteriorated portion formed on the glass substrate is proposed. The way to get.

For example, Patent Document 1 describes a method of forming a hole in glass. In this method, a pulsed laser beam is irradiated on the glass to form a damage track (guide hole) along the focal line of the laser beam in the glass. Afterwards, the glass is etched in an acid solution to expand the damage track (guide hole) in the glass, thereby creating a specific through hole. In addition, ultrasonic stirring is performed during etching.

Patent Document 2 describes a method of irradiating a glass-based substrate with a pulsed laser beam to form a damaged area inside the glass-based substrate, and etching the glass-based substrate in an etching solution to enlarge the damaged area, thereby A specific hole is formed on the glass substrate. The pH of the etching solution is 1.0 to 2.0. In etching, the etching solution is stirred by ultrasonic waves.

Patent Document 3 describes a process for forming through holes on a glass substrate. According to this process, a laser is irradiated to the glass substrate according to a specific pattern, thereby forming a plurality of etching paths. After that, a hydroxide-based etching material is used to specifically etch the glass substrate along the etching path. Prior art literature Patent literature

Patent Document 1: Japanese Special Form No. 2017-510531 Patent Document 2: US Patent Application Publication No. 2018/0068868 Specification Patent Document 3: Japanese Special Form No. 2018-531205

[The problem to be solved by the invention]

According to the techniques described in Patent Documents 1 to 3, there is room for further research on the geometric characteristics of the holes that also express the state near the openings of the holes on the glass substrate. In this regard, the present invention provides a glass substrate with a fine structure, the geometric characteristics of the holes are in a desired state, and the geometric characteristics of the holes also show the state near the hole opening. In addition, the present invention provides a method that uses an alkaline aqueous solution as an etching solution and is advantageous from the viewpoint of manufacturing such a glass substrate with a fine structure. [Technical means to solve the problem]

The present invention provides a glass substrate with a fine structure, which has a thickness of 50 μm to 2000 μm, and has the following hole: an opening on the first main surface of the glass substrate with a fine structure and the above thickness is expressed as t When satisfying the following conditions (i), (ii), (iii), (iv), and (v), (i) 0.4≦Φ _C /Φ _A ≦1.0, (ii) 70°≦θ≦90° , (Iii) Ra≦1.0 μm, (iv) 0≦D/t≦0.003, (v) 1.5≦L/Φ _C ≦30, Φ _A is the diameter of the opening of the hole on the first main surface, Φ _C It is the diameter of the hole at a position equidistant from the first main surface and the end of the hole on the opposite side of the opening in the thickness direction of the glass substrate with fine structure, and θ is the diameter along the hole The size of the angle formed by the first contour line and the second contour line on the cross section when the axis cuts the glass substrate with microstructure, the angle has a size of 90° or less, and the first contour line is derived from the microstructure The center of the thickness direction of the glass substrate is formed by the inner surface of the hole extending toward the first main surface, the second contour line is formed by the first main surface, and Ra is the thickness of the glass substrate with fine structure In the direction, the arithmetic mean roughness of the inner surface of the hole at a position equidistant from the first main surface and the end of the hole on the opposite side based on the Japanese Industrial Standard (JIS) B 0601:1994, D When the fine structure has "a ring-shaped peculiar portion formed on the cross-section of the third contour line that is outside the first contour line in the radial direction of the hole and connected to the second contour line" The fine structure of the glass substrate extends in the thickness direction and is farther away from the first main surface of the hole on the opposite side of the position on the coordinate axis with a positive value, which represents the distance in the thickness direction of the glass substrate with fine structure The coordinates of the position of the ring-shaped peculiar part farthest from the first main surface, L is the length of the hole in the thickness direction of the glass substrate with fine structure.

In addition, the present invention provides a method of manufacturing a glass substrate with a fine structure, which includes the steps of: irradiating a pulsed laser on the glass substrate to form a deteriorated part, and removing the deteriorated part by wet etching to form a glass substrate. In the step of forming holes in the substrate, in the above-mentioned wet etching, an alkaline aqueous solution with a characteristic value α of 0.01 or more defined by the following formula (1) is used as an etching solution, α=η×Vt formula (1), η It is the viscosity of the above-mentioned etching solution [mPa·s], and Vt is the product of the molar concentration of alkali ions in the above-mentioned etching solution [mol/L] and the volume Vi [nm ³ ] assuming that the alkali ions are spheres. [Effects of Invention]

The geometric characteristics of the holes of the glass substrate with microstructures are in a desired state, and the geometric characteristics of the holes also represent the state near the opening of the hole. In addition, the above method uses an alkaline aqueous solution as an etching solution and is advantageous from the viewpoint of manufacturing the above-mentioned glass substrate with a fine structure.

When using wet etching using hydrofluoric acid as an etching solution to expand defects such as damage traces or guide holes formed by irradiating a pulsed laser on a glass substrate, depending on the type of glass, relative to the diffusion of reactive species Speed, the etching speed tends to become faster. As a result, in the area away from the inside of the hole from the main surface of the glass substrate, the amount of reactive species consumed is less, and it is easy to make the aperture near the center of the thickness direction of the glass substrate smaller than the opening of the hole on the main surface of the glass substrate. The diameter becomes smaller. In other words, the hole existing near the center in the thickness direction of the glass substrate tends to shrink.

In order to form a hole in the thickness direction of the glass substrate with a smaller change in diameter between one end and the other end of the hole (here, it is expressed as a "highly linear hole"), consider applying ultrasonic waves in the etching solution. Improve the diffusion rate of reactive species. However, if ultrasonic waves with a relatively low frequency (for example, 28-50 kHz) are used in order to increase the diffusion rate, depending on the mechanical properties of the glass used, the glass substrate is likely to be cracked or damaged. In addition, there is a possibility that the main surface of the glass substrate is over-etched, and the vicinity of the opening of the hole is formed in a part that is concave on the surface of the glass substrate, or formed by a part that is raised from the surface of the substrate Near the opening of the hole. On the other hand, if ultrasonic waves with a relatively high frequency (for example, above 80 kHz) are used, although the glass substrate is not prone to cracking or damage, it is difficult to increase the diffusion rate of reactive species and the resulting holes are prone to shrinkage. Furthermore, the use of ultrasonic waves may also cause spatial differences in the intensity of ultrasonic waves in the etching grooves due to the attenuation of ultrasonic waves and the overlap of reflected waves. In this case, it is easy to increase the surface roughness of the surface of the glass substrate or the inner surface of the hole (for example, the arithmetic average roughness Ra based on Japanese Industrial Standards (JIS) B 0601:1994). In addition, the difference in the pore diameters among the plurality of holes tends to become large. In particular, there are situations where it is difficult to form a plurality of holes with a uniform pore size on a glass substrate of a larger size. Furthermore, since hydrofluoric acid is highly corrosive, etching using hydrofluoric acid requires corrosion-resistant equipment, as well as equipment to ensure the safety of operators. In addition, the treatment of hydrofluoric acid as industrial waste is burdensome.

In this regard, it is considered to use an alkaline aqueous solution as an etching solution. In this case, the etching rate of the etching solution is likely to be slower than that of acids such as hydrofluoric acid, and the reactive species of the etching solution are easily diffused in the area away from the inside of the hole from the main surface of the glass substrate. As a result, even if ultrasonic waves are not applied, holes with high linearity are easily formed. On the other hand, if an alkaline aqueous solution is used as the etching solution, the etching rate is slow, and therefore, there is room for improvement from this viewpoint. In this regard, the inventors have repeatedly studied and found that by using a specific alkali solution as an etching solution in wet etching, holes with required geometric characteristics can be formed on the glass substrate at the required etching speed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the following describes an example of the present invention, but the present invention is not limited to the following embodiments.

As shown in FIG. 1, the glass substrate 10 with a fine structure has a thickness of 50 μm to 2000 μm. The glass plate 10 with a fine structure has holes 20. The hole 20 is, for example, a through hole. The hole 20 may be a bottomed hole. The hole 20 opens on the first main surface 11 of the glass plate 10 with a fine structure. In addition, the hole 20 satisfies the following conditions (i), (ii), (iii), (iv), and (v) when the thickness of the glass substrate 10 with a fine structure is expressed as t. The thickness t is, for example, the thickness of the glass plate 10 with a fine structure near the opening 21 of the hole 20 of the first main surface 11. (I) 0.4≦Φ _C /Φ _A ≦1.0 (ii) 70°≦θ≦90° (iii) Ra≦1.0 μm (iv) 0≦D/t≦0.003 (v) 1.5≦L/Φ _C ≦30

Φ _A is the diameter of the opening 21 of the hole 20 of the first main surface 11. Φ _C is the diameter of the hole 20 at an equidistant position in the thickness direction of the glass substrate 10 with fine structure, and the opposite side from the first main surface 11 and the opening 21 of the hole 20. θ is the size of the angle formed by the first contour line L1 and the second contour line L2 on the cross section where the glass substrate 10 with fine structure is cut along the axis of the hole 20. The angle has a size of 90° or less. The contour line L1 is formed by the inner surface of the hole 20 extending from the center in the thickness direction of the glass substrate 10 with the microstructure to the first main surface 11, and the second contour line L2 is formed by the first main surface 11. Ra is an arithmetic based on JIS B 0601:1994 at the inner surface of the hole 20 at a position equidistant from the first main surface 11 and the end of the hole 20 in the thickness direction of the glass substrate 10 with fine structure Average roughness. D is when the hole 20 has "formed on the above-mentioned cross-section a ring-shaped peculiar part of the third contour line L3 that is the radial outer side of the hole 20 with respect to the first contour line L1 and is connected to the second contour line L2." The glass substrate 10 with fine structure extends in the thickness direction and is farther from the first main surface 11 on the opposite side of the hole 20 at the position of the positive coordinate axis Z, which is expressed in the thickness direction of the glass substrate 10 with fine structure The coordinates of the position of the ring-shaped peculiar part farthest from the first main surface 11. L is the length of the hole 20 in the thickness direction of the glass substrate 10 with a fine structure.

In the cross section that appears when the glass substrate 10 with fine structure is cut along the axis of the hole 20, when the first contour line L1 changes from the center of the thickness direction of the glass substrate 10 with fine structure to the direction in which the first main surface 11 extends , Determine θ with the smallest value of θ.

Since the hole 20 satisfies the above-mentioned conditions (i) and (ii), the center of the hole 20 in the thickness direction of the glass substrate 10 with a fine structure shrinks less, and the linearity of the hole 20 is higher. The hole 20 preferably satisfies the condition of 0.5≦Φ _C /Φ _A ≦1.0, and more desirably satisfies the condition of 0.6≦Φ _C /Φ _A ≦1.0. In addition, the hole 20 preferably satisfies the condition of 80°≦θ≦90°, and more desirably satisfies the condition of 85°≦θ≦90°. Among them, "small shrinkage" means that the hole diameter near the center in the thickness direction of the glass substrate is smaller than the diameter of the opening of the hole on the main surface of the glass substrate.

Since the hole 20 satisfies the above-mentioned condition (iii), the unevenness of the inner surface of the hole 20 is small, and the inner surface of the hole 20 is easily smoothed. Thereby, for example, the conductive material can be easily attached to the inner surface of the hole 20 to obtain a conductive film, and the attached conductive material is difficult to peel off. In addition, the conductive film is easy to have uniform characteristics, and it is easy to obtain the required electrical characteristics. The hole 20 preferably satisfies the condition of Ra≦0.9 μm, and more desirably satisfies the condition of Ra≦0.8 μm.

Since the hole 20 satisfies the above condition (iv), θ is less than 90°, and even if the hole 20 has a ring-shaped special part, the length of the ring-shaped special part in the axial direction of the hole 20 is small, and the length of the part where the hole 20 extends linearly Easy to grow. The hole 20 preferably satisfies the condition of 0≦D/t≦0.0025, and more desirably satisfies the condition of 0≦D/t≦0.002.

As shown in the glass substrate 10 with a fine structure shown in FIG. 1, when D is a positive value, a ring-shaped convex portion is formed as a ring-shaped peculiar portion. It is considered that the reason for the formation of such a ring-shaped convex portion is that since the liquid with a relatively high concentration of eluate flows out from the inside of the hole near the surface of the hole, the etching rate tends to be lower than that of the flat portion. In particular, in an alkali-free glass with a low alkali component ratio of easily soluble components, the etching rate is significantly reduced, thereby forming a convex shape. As shown in the glass substrate 100 with a fine structure of the reference example shown in FIG. 2, when D is a negative value, a ring-shaped concave portion is formed as a ring-shaped peculiar portion. The glass substrate 100 with a microstructure has the same structure as the glass substrate 10 with a microstructure except for the parts specifically described. It is believed that the reason for the formation of such a ring-shaped recess is that the pumping effect is produced by irradiating the hole portion with ultrasonic waves, and the flow rate of the liquid inside and on the hole surface becomes faster. As a result, it is considered that the etching rate in the vicinity of the hole surface is increased, and the recesses are formed. This effect is produced regardless of whether the etchant is acid or alkali.

L/Φ _C represents the aspect ratio of the hole 20. Since the hole 20 satisfies the above condition (v), the hole 20 has a required aspect ratio. Thus, the use of the glass substrate 10 with a fine structure can increase the integration of the semiconductor package. The hole 20 can satisfy the condition of 2≦L/Φ _C ≦30, and can also satisfy the condition of 3≦L/Φ _C ≦30. When the hole 20 is a through hole, the value of L coincides with the value of t.

In addition, FIG. 1 and FIG. 2 are schematic diagrams for expressing each parameter easily and making the explanation easy to understand. For example, the actual hole 20 also has a conical (taper-shaped) shape near its opening. In addition, the hole 20 in FIGS. 1 and 2 is described as being roughly divided into three parts in the thickness direction. It should be noted that it is described in order to easily understand the difference between Φ _A and Φ _C , or the angle θ, the first contour line L1, and "shrinkage".

The glass forming the glass substrate 10 with a microstructure is not limited to a specific glass. In consideration of application to semiconductor packaging, it is preferable that the alkali component content in the glass forming the glass substrate 10 with a fine structure is low. The reason is that it is easy to make the linear expansion coefficient of the glass substrate 10 with a fine structure close to that of the silicon substrate, and it is easy to realize good chemical resistance. In addition, by thermal diffusion or treatment with acid or alkali, it is possible to prevent the alkali component contained in the glass substrate 10 with a fine structure from eluting and diffusing into the semiconductor element. As a result, it is less likely to cause a decrease in electrical insulation. In addition, it is difficult to adversely affect electrical characteristics such as dielectric constant (ε) and dielectric loss tangent (tanδ) and high-frequency characteristics.

In the glass forming the glass substrate 10 with a fine structure, the total content of Li ₂ O, Na ₂ O, and K ₂ O is preferably less than 10 mol %. In this case, the glass substrate 10 with a fine structure is likely to have characteristics required as a substrate for semiconductor packaging. In the glass forming the glass substrate 10 with fine structure, the sum of the contents of Li ₂ O, Na ₂ O, and K ₂ O (Li ₂ O+Na ₂ O+K ₂ O) is more preferably less than 5 mol %, and more preferably less than 0.5 mol%.

The method of manufacturing the glass substrate 10 with a microstructure includes the following steps (I) and (II), for example. (I) A pulsed laser is irradiated to the glass substrate to form a deteriorated part. (II) A hole is formed in the glass substrate by removing the deteriorated part by wet etching.

In the above-mentioned (II) wet etching, an alkaline aqueous solution whose characteristic value α defined by the following formula (1) is 0.01 or more is used as an etching solution. Furthermore, η is the viscosity of the above-mentioned etching solution [mPa·s], and Vt is the product of the molar concentration of alkali ions in the etching solution [mol/L] and the volume Vi[nm ³ ] assuming that the alkali ions are spheres. Furthermore, in this specification, the viscosity η of the etching solution is the value at 20°C. α=η×Vt formula (1)

Typically, the etching rate of the etchant on the deteriorated part of the glass is greater than the etching rate of the etchant on the undeteriorated area of the glass.

If the characteristic value α is 0.01 or more, the etching solution has a viscosity above a specific value, and the etching solution contains alkali components at the required concentration. Thereby, the etching solution can exert appropriate reactivity.

The characteristic value α preferably satisfies the condition of 0.04≦α≦0.4, and more desirably satisfies the condition of 0.05≦α≦0.3. Thereby, the viscosity of the etching solution is easily reduced, and the reactive species of the etching solution are easy to move. Thus, the reactive species can easily diffuse appropriately and reach the entire metamorphic part. In addition, the molar volume Vi of the alkali ions contained in the etching solution tends to be below a specific value, and the alkali ions are easily diffused. Therefore, the reactive species of the etching solution can easily reach the entire degraded part. As a result, even if ultrasonic waves are not applied to the etching liquid, the holes 20 having high linearity can be formed.

For the viscosity η of the etching solution, for example, refer to Wolf, AV, Aqueous Solutions and Body Fluids, Hoeber Medical Division, Harper & Row, 1966. and Sohnel, O., and Novotny, P., Densities of Aqueous Solutions of Inorganic Substances, Elsevier, Amsterdam, 1985. and other documents. The viscosity of the etching solution can be determined using a rotary viscometer or a tuning fork viscometer. In addition, the measurement of the viscosity of the etching solution can be performed with a capillary viscometer in accordance with the method of measuring the viscosity of liquids in JIS Z 8803:2011. As a specific example of the rotary viscometer, the model B-ONE TOUCH-R manufactured by LAMY Rheology can be cited. The viscosity of the etching solution can be measured by using this viscometer at 20°C.

In the glass substrate used in the above method of manufacturing the glass substrate 10 with a fine structure, the sum of the contents of Li ₂ O, Na ₂ O, and K ₂ O is preferably less than 10 mol %. The sum of the contents of Li ₂ O, Na ₂ O, and K ₂ O (Li ₂ O+Na ₂ O+K ₂ O) is more preferably less than 5 mol%, and more preferably less than 0.5 mol%. In addition, the glass substrate may be substantially free of alkali metal oxides such as Li ₂ O, Na ₂ O, and K ₂ O. Among them, "substantially not contained" means that the content of these components in the glass is less than 0.1 mol%, more preferably less than 0.05 mol%, and more preferably less than 0.01 mol%.

The alkaline aqueous solution is, for example, an aqueous potassium hydroxide solution, an aqueous sodium hydroxide solution, or a mixture of an aqueous potassium hydroxide solution and an aqueous sodium hydroxide solution. In this case, the alkali ion contained in the etching solution has a volume Vi that is favorable for the characteristic value α to satisfy the required conditions. Furthermore, the ion radius of sodium ions used to determine the volume Vi of sodium ions is, for example, 0.095 nm, and the ion radius r of potassium ions used to determine the volume of potassium ions Vi is, for example, 0.133 nm. The plasma radius is based on L. Pauling, The Nature of the Chemical Bond, 3 ^rd Edn., Cornell University Press, Ithaca, NY (1960), FA Cotton, G. Wilkinson, and the translation of "Cotton· Wilkinson Inorganic Chemistry" Peifengkan, 1987, and the value of literature published by Hirozo Nagashima, Hirotosan Sano, and Ko Tomita "Inorganic Chemistry" practice teaching.

In the step (II), in order to achieve etching from only one side of the glass substrate, a surface protection coating agent can be applied to one of the main surfaces of the glass substrate. As such a surface protection coating agent, commercially available products such as SILITECT-II (manufactured by Trylaner International) can be used.

The etching time or the temperature of the etching solution is selected according to the shape of the altered part or the target processing shape. Since the etching time also depends on the thickness of the glass substrate, it is not particularly limited, and is, for example, 30 to 180 minutes.

The temperature of the alkaline aqueous solution in wet etching is, for example, 60°C to 130°C. If it is considered to increase the moving speed of the reactive species in the etching solution to properly diffuse the reactive species, allow the reactive species to reach the entire metamorphic part, and increase the reaction rate, the higher the temperature of the alkaline aqueous solution is more advantageous. During the step (II), in order to adjust the etching rate, the temperature of the etching solution can be changed. For example, by using a reaction tank made of polytetrafluoroethylene (PTFE) or a reaction tank made of nickel, the temperature of the alkaline aqueous solution can be raised to around 130° C. to perform wet etching. On the other hand, a reaction layer made of heat-resistant vinyl chloride or polyethylene can also be used. Heat-resistant vinyl chloride or polyethylene is a general-purpose material with high chemical resistance and good processability. Thereby, it is easy to reduce the manufacturing cost of the glass substrate 10 with a fine structure. When using a reaction layer made of heat-resistant vinyl chloride or polyethylene, the temperature of the alkaline aqueous solution is preferably below 100°C.

The glass forming the glass substrate 10 with fine structure or the glass forming the glass substrate used in the above-mentioned manufacturing method is not limited to a specific glass. In glass, for example, the absorption coefficient a at the center wavelength of the pulsed laser of the above step (I) is 1-50/cm. The center wavelength of a pulsed laser is typically less than 535 nm. The wavelength of the pulsed laser can be in the range of 350-360 nm, for example.

The absorption coefficient a can be calculated by measuring the transmittance and reflectance of a glass substrate of thickness t (cm). For a glass substrate with a thickness of t (cm), use a spectrophotometer (for example, the UV-visible-near-infrared spectrophotometer V-670 manufactured by JASCO Corporation) to measure the transmittance T of a specific wavelength (wavelength below 535 nm) %) and reflectivity R (%) when the incident angle is 12°. Calculate the absorption coefficient a (/cm) from the measured value using the following formula. a=(1/t)*ln{(100－R)/T}

The absorption coefficient a of the glass at the center wavelength of the pulsed laser is preferably 1-50/cm, more preferably 3-40/cm.

In the step (I), the pulsed laser is usually collected by a lens by focusing on the inside of the glass substrate. For example, when a through hole is formed in a glass substrate, the pulse laser is usually focused on the vicinity of the center in the thickness direction of the glass substrate. Moreover, when processing only the upper surface side of the glass substrate (the incident side of the pulse laser), the pulse laser is usually focused on the upper surface side of the glass substrate. On the contrary, when processing only the lower surface side of the glass substrate (the side opposite to the incident side of the pulse laser), the pulse laser is usually focused on the lower surface side of the glass substrate. However, as long as the deformed part can be formed, the pulse laser can also be focused on the outside of the glass substrate. For example, a pulsed laser can be focused from the upper surface or the lower surface of the glass substrate to a position only a certain distance (for example, 1.0 mm) from the glass substrate. In other words, as long as the deteriorating part can be formed on the glass substrate, the pulse laser can also be focused on the position within 1.0 mm from the upper surface of the glass substrate to the front direction (the direction opposite to the direction of the pulse laser) (including the glass substrate) The upper surface), or the position within 1.0 mm (including the position of the lower surface of the glass substrate) from the lower surface of the glass substrate to the rear (the direction of the pulse laser penetrating the glass), or the inside.

The pulse width of the pulse laser is preferably 1 to 200 ns (nanoseconds), more preferably 1 to 100 ns, and even more preferably 5 to 50 ns. In addition, if the pulse width is greater than 200 ns, the tip value of the pulse laser may decrease, and the processing may not proceed smoothly. Irradiate the glass substrate with laser light consisting of 5-100 μJ/pulse energy. By increasing the energy of the pulse laser, the length of the metamorphic part can be increased in proportion to it. The beam quality M ₂ value of the pulse laser can be 2 or less, for example. By using a pulse laser with an M ₂ value of 2 or less, it is easy to form tiny pores or tiny grooves.

In the step (I), the pulsed laser can be Nd: the higher harmonic of YAG laser, Nd: the higher harmonic of YVO ₄ laser, or Nd: the higher harmonic of YLF laser. The higher harmonics are, for example, the second harmonic, the third harmonic, or the fourth harmonic. The wavelength of the second harmonic of these lasers is around 532～535 nm. The wavelength of the third harmonic is around 355～357 nm. The wavelength of the fourth harmonic is around 266～268 nm. By using these lasers, glass substrates can be processed at low prices.

As a device used in the laser processing of the step (I), for example, a high-repetition solid pulse UV laser manufactured by Kochlun: AVIA355-4500 can be cited. In the case of this device, it is the third harmonic Nd: YVO ₄ laser. When the repetition frequency is 25 kHz, the maximum laser power of about 6 W can be obtained. The wavelength of the third harmonic is 350～360 nm.

In a typical optical system, the oscillating laser is enlarged by a beam expander to 2~4 times (at this time point ϕ is 7.0~14.0 mm), and the center part of the laser is intercepted by a variable aperture. The optical axis is adjusted by the galvanometer mirror, and the focal position is adjusted by the fθ lens of about 100 mm and the light is focused on the glass substrate.

The focal length L (mm) of the lens is, for example, in the range of 50-500 mm, and can be selected from the range of 100-200 mm.

In addition, the beam diameter S (mm) of the pulse laser is, for example, in the range of 1-40 mm, and can be selected from the range of 3-20 mm. Wherein, the beam diameter S is the beam diameter of the pulsed laser when it is incident on the lens, which means the diameter within the range of [1/e ² ] times the intensity relative to the intensity of the center of the beam.

In the step (I), the value obtained by dividing the focal length L by the beam diameter S, that is, the value of [L/S] is 7 or more, preferably 7 or more and 40 or less, or 10 or more and 20 or less. This value is a value related to the light-gathering property of the laser irradiated on the glass. The smaller the value, it means that the laser is locally focused, and it is difficult to make a uniform and long deteriorated part. If the value is less than 7, the following problem occurs. That is, the laser power becomes too strong near the beam waist, and cracks are likely to occur inside the glass substrate.

In step (I), there is no need to pre-treat the glass before irradiating the pulsed laser (for example, forming a film that promotes the absorption of the pulsed laser). However, this treatment can also be performed.

The size of the aperture can be changed to change the diameter of the laser, thereby changing the numerical aperture (NA) to 0.020～0.075. If the NA becomes too large, the energy of the laser is only concentrated near the focal point, and it is not possible to effectively form the altered part along the thickness direction of the glass substrate.

Furthermore, a pulsed laser with a smaller NA is irradiated, whereby a one-time pulse irradiation is used to form a longer deformed part in the thickness direction. Therefore, it is effective in improving the yield time.

Preferably, the repetition frequency is set to 10-25 kHz and the sample is irradiated with laser. In addition, by changing the focal position due to the thickness direction of the glass substrate, the position (upper surface side or lower surface side) of the deteriorated portion formed on the glass substrate can be adjusted to the best.

Furthermore, by the operation from the control PC, the laser output, the movement of the galvanometer mirror, etc. can be controlled. Based on the 2D drawing data made by CAD software, the laser can be irradiated on the glass substrate at a specific speed.

In the part where the laser is irradiated, there is formed an altered part that is different from other parts of the glass substrate. The deteriorated part can be easily distinguished by an optical microscope or the like. Although each piece of glass differs according to its composition, the altered part is roughly formed in a cylindrical shape. The deteriorated part can reach the vicinity of the lower surface from the vicinity of the upper surface of the glass substrate.

It is believed that the degraded part is the part where defects such as the E'center or non-crosslinked oxygen are generated by the photochemical reaction caused by the laser irradiation; or the "maintenance high" caused by the rapid heating or rapid cooling caused by the laser irradiation The part of the sparse glass structure in the temperature zone".

In the case of using the conventional processing method of a femtosecond laser device, the laser is scanned in the depth direction (thickness direction of the glass substrate) by overlapping the irradiation pulses to form the deformed part. On the other hand, by using the laser irradiation and wet etching manufacturing method of the step (I) of the present invention together, the altered part can be formed by one-time pulse laser irradiation.

As the conditions selected in the step (I), for example, the absorption coefficient of glass is 1-50/cm, the pulse laser width is 1-100 ns, and the energy of pulse laser is 5-1000 μJ/pulse. The combination of wave, wavelength of 350～360 nm, pulse laser beam diameter S of 3～20 mm, and lens focal length L of 100～200 mm.

Furthermore, if necessary, the glass substrate may be polished in order to reduce the difference in the diameter of the deteriorated part before performing the wet etching. If the polishing is excessive, the effect of wet etching on the deteriorated part is weakened. Therefore, the polishing depth is preferably 1-20 μm from the upper surface of the glass substrate.

The size of the deformed part formed in step (I) varies according to the beam diameter S of the laser when it is incident on the lens, the focal distance L of the lens, the absorption coefficient of the glass, the power of the pulsed laser, and so on. The resulting modified part has a diameter of, for example, about 5 to 200 μm, or about 10 to 150 μm. In addition, the depth of the degraded part also varies according to the above-mentioned laser irradiation conditions, the absorption coefficient of the glass, and the thickness of the glass, and may be, for example, about 50 to 2000 μm.

In addition, as a method of forming a deteriorated part, it is not limited to the above aspect. For example, by irradiation from the aforementioned femtosecond laser device, the deformed part or the processed hole can be formed.

The optical system used to irradiate the pulsed laser can be an optical system with a rotating Axicon lens. If this optical system is used to condense the laser beam, a Bessel beam can be formed. For example, it is possible to obtain a Bessel beam in which the light at the center of a length of several mm to several tens of mm in the optical axis direction of the irradiation position of the pulse laser maintains a high intensity. Thereby, the focal depth can be deepened, and the beam diameter can be reduced. As a result, it is possible to form "a deformed portion that is substantially uniform in the thickness direction of the glass substrate".

The glass forming the glass substrate 10 with a fine structure or the glass forming the glass substrate used in the above manufacturing method may be, for example, aluminoborosilicate glass having the following composition. A glass containing SiO ₂ 45～68%, B ₂ O ₃ 2～20%, Al ₂ O ₃ 3～20%, TiO ₂ 0.1～5.0%, ZnO 0～9%, and Li ₂ O+Na ₂ O+K ₂ O 0～15%.

In the above-mentioned aluminoborosilicate glass, Li ₂ O+Na ₂ O+K ₂ O is preferably less than 10 mol%, more preferably less than 5 mol%, and more preferably less than 0.5 mol% %.

In the above-mentioned aluminoborosilicate glass, CeO ₂ 0-3% and Fe ₂ O ₃ 0-1% are also contained as coloring components.

The above-mentioned aluminoborosilicate glass contains TiO ₂ as an essential component. The content of TiO ₂ in the aluminoborosilicate glass is 0.1 mol% or more and 5.0 mol% or less. From the viewpoint of improving the smoothness of the inner surface of the hole obtained by pulse laser irradiation, the content of TiO ₂ is preferably 0.2-4.0 mol%, more preferably 0.5-3.5 mol%, and more preferably It is 1.0～3.5 mol%. By appropriately containing TiO _{2 in} the above-mentioned aluminoborosilicate glass, it is easy to form a deteriorated part by relatively weak laser irradiation. In addition, the deteriorated part can be easily removed by wet etching in the subsequent steps. In addition, the bonding energy of TiO ₂ is roughly the same as the energy of ultraviolet light, and it is easy to absorb ultraviolet light. By appropriately containing TiO ₂ , the coloring can also be controlled by the charge transfer absorption and the interaction with other colorants. Therefore, by adjusting the content of TiO ₂ , the absorption of specific light can become appropriate. Since glass has an appropriate absorption coefficient, it is easy to form a modified part with holes formed by wet etching. Therefore, from these viewpoints, it is preferable to appropriately contain TiO ₂ .

The above-mentioned aluminoborosilicate glass may contain ZnO as an optional component. The content of ZnO in the aluminoborosilicate glass is preferably 0～9.0 mol%, more preferably 1.0～8.0 mol%, more preferably 1.5～5.0 mol%, particularly preferably 1.5～3.5 mol% %. Like TiO _2, ZnO exhibits absorption in the ultraviolet light region.

The above-mentioned aluminoborosilicate glass may contain CeO ₂ as a coloring component. Especially when CeO ₂ is used in combination with TiO ₂ , it is possible to easily form a modified part. The content of CeO ₂ is preferably 0-3.0 mol%, more preferably 0.05-2.5 mol%, further preferably 0.1-2.0 mol%, and particularly preferably 0.2-0.9 mol%.

Fe ₂ O ₃ is also effective as a coloring component, and the above-mentioned aluminoborosilicate glass may also contain Fe ₂ O ₃ . In particular, the combined use of TiO ₂ and Fe ₂ O ₃ , or the combined use of TiO ₂ , CeO ₂ and Fe ₂ O ₃ , makes it easy to form a modified portion. The content of Fe ₂ O ₃ in the aluminoborosilicate glass is preferably 0-1.0 mol%, more preferably 0.008-0.7 mol%, more preferably 0.01-0.4 mol%, particularly preferably 0.02- 0.3 mol%.

The aluminoborosilicate glass is not limited to the components listed above. By containing appropriate coloring components, the absorption coefficient of the glass at a specific wavelength (wavelength below 535 nm) can be 1-50/cm, preferably 3～ 40/cm.

Aluminoborosilicate glass may contain MgO as an optional component. Among alkaline earth metal oxides, MgO has the characteristics of suppressing the increase of the thermal expansion coefficient while not lowering the strain point, and also improves the solubility. The content of MgO in the aluminoborosilicate glass is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, furthermore preferably 10.0 mol% or less, and particularly preferably 9.5 mol% or less. In addition, the content of MgO is more preferably 2.0 mol% or more, more preferably 3.0 mol% or more, furthermore preferably 4.0 mol% or more, and particularly preferably 4.5 mol% or more.

The aluminoborosilicate glass may contain CaO as an optional component. Like MgO, CaO has the characteristics of suppressing the increase in the coefficient of thermal expansion while not lowering the strain point, and also improves solubility. The content of CaO in the aluminoborosilicate glass is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, furthermore preferably 10.0 mol% or less, and particularly preferably 9.3 mol% or less. In addition, the content of CaO is more preferably 1.0 mol% or more, more preferably 2.0 mol% or more, still more preferably 3.0 mol% or more, and particularly preferably 3.5 mol% or more.

Aluminoborosilicate glass may contain SrO as an optional component. SrO, like MgO and CaO, has the characteristics of suppressing the increase in the thermal expansion coefficient while not lowering the strain point, and also improves the solubility. Therefore, in order to improve the devitrification characteristics and acid resistance, SrO can be contained. The content of SrO in the aluminoborosilicate glass is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, furthermore preferably 10.0 mol% or less, and particularly preferably 9.3 mol% or less. In addition, the content of SrO is more preferably 1.0 mol% or more, more preferably 2.0 mol% or more, furthermore preferably 3.0 mol% or more, and particularly preferably 3.5 mol% or more.

In this specification, the upper limit and lower limit of the numerical range (content of each component, value calculated from each component, and each physical property, etc.) can be appropriately combined.

The coefficient of thermal expansion of the glass forming the glass substrate 10 with fine structure or the glass forming the glass substrate used in the above-mentioned manufacturing method is, for example, 100×10 ^-7 /°C or less, more preferably 70×10 ^-7 /°C or less, more preferably 60×10 ^-7 /°C or less, more preferably 50×10 ^-7 /°C or less. In addition, the lower limit of the thermal expansion coefficient is not particularly limited, and may be 10×10 ^-7 /°C or higher, or 20×10 ^-7 /°C or higher.

The thermal expansion coefficient of glass is measured as follows, for example. First, make a cylindrical glass sample with a diameter of 5 mm and a height of 18 mm. This is heated from 25°C to the yield point of the glass sample, and the elongation of the glass sample at each temperature is measured to calculate the thermal expansion coefficient. Calculate the average thermal expansion coefficient in the range of 50～350℃, and determine the average thermal expansion coefficient. Example

Hereinafter, the present invention will be described in more detail with examples. In addition, the present invention is not limited to the following examples. First, the evaluation methods related to Examples and Comparative Examples will be described.

＜Thickness＞ A micrometer (manufactured by Mitutoyo Corporation, product name: IP54) was used to measure the thickness of the glass substrate with a fine structure in each example and each comparative example. The hole formed on the glass substrate with fine structure is a through hole, therefore, the thickness of the glass substrate with fine structure is regarded as the length of the hole. The results are shown in Table 1.

<Evaluation of the shape of the hole> Using a three-dimensional rangefinder (manufactured by Nikon, product name: VMR-6555), the holes formed in the glass with fine structure of each example and each comparative example were focused on the A surface and Enlarged image with 8 times magnification of C side. When an enlarged image is obtained, the illumination of the object is carried out by epi-illumination, and the light intensity level is set to 55%. The A surface is a plane including one main surface of the glass with fine structure corresponding to the main surface of the glass substrate on which the pulsed laser is incident. C plane is a plane with equidistant distance from A plane and B plane. The B surface is the main surface opposite to the main surface of the glass with the fine structure. For the magnified image of the glass with fine structure focusing on the A surface and the C surface, image analysis software is used for image analysis, and the shape of the A surface and the C surface is evaluated. In the evaluation of the shape of the hole, the position of the boundary between the hole and the wall of the glass substrate is specified at 180 locations with an interval of 2° around the axis of the hole, and the approximate circle is specified by the least square method based on the location information of the boundary of the 180 locations . The diameter of the approximate circle is regarded as the hole diameter, and the hole diameter Φ _{A of the A} surface and the hole diameter Φ _{C of the} C surface are determined. The results are shown in Table 1.

The glass substrates with fine structures of the respective Examples and Comparative Examples were cut to expose the inner surface of the hole, and the surface that appeared by the cut was polished. Polishing is performed in such a way that the surface obtained by polishing can be regarded as a plane including the axis of the hole. After that, using a laser microscope (manufactured by Keyence Corporation, product name: VK-8500), in a measurement area that crosses the C plane and has a measurement length of about 200 μm, the unevenness of the inner surface of the hole is measured to obtain Roughness curve. From this roughness curve, the arithmetic average roughness Ra based on JIS B 0601:1994 is calculated. Observe the surface obtained by grinding. In this surface, the contour line formed by the inner surface of the hole extending from the center in the thickness direction of the glass substrate with the fine structure to the surface A, and the surface contained in the surface A The angle (inclination angle) θ formed by the contour line formed by the main surface of the glass substrate with fine structure is determined, and the above angle θ has a size of 90° or less. In addition, the area near the A surface in the surface obtained by polishing was observed to confirm the presence or absence of the ring-shaped peculiar part. Specify the position of the ring-shaped peculiar part farthest from the main surface of the glass substrate with the fine-structure included in the A surface in the thickness direction of the glass substrate with a microstructure, and determine the D value related to the ring peculiar part based on this position . The results are shown in Table 1.

＜Linear expansion coefficient＞ Prepare a prism-shaped sample with a size of 4 mm×4 mm×20 mm used in the Examples and Comparative Examples. The sample has the same composition as the glass of composition A, composition B, composition C, and composition D The glass and those made of monocrystalline silicon. Using a thermomechanical analysis device (manufactured by NETZSCH, product name: TMA 402F1 Hyperion) at a temperature range of -100°C to 500°C and a temperature rise rate of 5°C/min, the temperature around the sample is changed under atmospheric pressure. The length of the sample at temperature is measured. Based on the measurement results, in accordance with JIS R 3102: 1995 (Test Method for the Average Linear Expansion Coefficient of Glass), determine the average linear expansion coefficient CTE of each glass and single crystal silicon in the temperature range of 0℃～300℃. The results are shown in Table 2. The CTE(G)/CTE(Si) in Table 2 is the ratio of the CTE of glass in the temperature range of 0℃～300℃ to the CTE of single crystal silicon in the temperature range of 0℃～300℃.

<Acid resistance test> According to the German industrial standard DIN12116, the acid resistance test of glass is carried out. Crush the glass having the same composition as the glass of composition A, composition B, composition C, and composition D used in the examples and comparative examples, and prepare 2 g of the pulverized product with a particle diameter of 300 to 500 μm and test Pieces. Place the test piece in a boiling aqueous solution of 6 mol/L hydrochloric acid, and measure the mass of the test piece after 6 hours. Based on the measurement result, the mass reduction of half of the surface loss was calculated according to DIN12116, and the acid resistance grade was classified according to the following criteria. The results are shown in Table 2. Level 1: The mass reduction of half of the surface loss does not reach 0.7 mg/100cm ² . Level 2: The mass reduction of half of the surface loss is 0.7 mg/100cm ² or more and less than 1.5 mg/100cm ² . Level 3: The mass reduction of half of the surface loss is 1.5 mg/100cm ² or more and less than 15 mg/100cm ² . Level 4: The mass reduction of half of the surface loss is 15 mg/100cm ² or more.

<Alkali resistance test> According to ISO 695, the alkali resistance test of glass is carried out. A glass sample having the same composition as the glass of composition A, composition B, composition C, and composition D used in the examples and comparative examples was placed in a boiling aqueous solution of mixed alkali, and after 3 hours, The quality of the sample is measured. As an aqueous solution of mixed alkali, a mixed solution of 1 mol/L of sodium hydroxide (NaOH) aqueous solution and 0.5 mol/L of sodium carbonate (Na ₂ CO ₃ ) is used. According to the mass reduction of the sample, the alkali resistance level is classified according to ISO 695 according to the following criteria. The results are shown in Table 2. Grade 1: The mass reduction of glass does not reach 75 mg/100cm ² . Grade 2: The mass reduction of glass is 75 mg/100cm ² or more and less than 175 mg/100cm ² . Grade 3: The mass reduction of glass is more than 175 mg/100cm ² .

＜etch rate＞ Put 500 g of the etching solution of each example and each comparative example into a polyethylene beaker with a volume of 1 liter, and use a water bath to adjust the temperature of the etching solution to 75°C. In this state, put a glass plate of a specific size into a beaker and immerse it in the etching solution. The etching rate of each etching solution was determined based on the time required until the decrease in the thickness of the glass plate became 70 μm. The results are shown in Table 3.

＜Characteristic value α＞ Use the value based on the above document as the viscosity of the etching solution. The viscosity is the viscosity at 20°C. Use the value based on the above-mentioned literature as the ion radius of sodium ion and potassium ion. Based on this value, the ion volume is determined assuming that the alkali ion is a ball, and the characteristic value α of each etching solution is determined based on the above-mentioned formula (1). The results are shown in Table 3. In addition, the relationship between the characteristic value α and the etching rate is shown in FIG. 3.

<Example 1> A glass substrate having a thickness of 0.470 mm and a main surface of 30 mm ^{2 was} prepared. The glass forming this glass substrate has the following composition A. (Composition A) Glass type: alkali-free glass (aluminum borosilicate glass) Glass composition: SiO ₂ (63 mol%), B ₂ O ₃ (10 mol%), Al ₂ O ₃ (12 mol%) ), TiO ₂ (3 mol%), ZnO (3 mol%), Li ₂ O+Na ₂ O+K ₂ O (0 mol%), MgO+CaO+SrO+BaO (9 mol%)

The glass substrate was irradiated with a pulsed laser under the following conditions to form a deteriorated part. Wavelength of pulsed laser: 355 nm Irradiation energy of pulse laser: 500 μJ/pulse wave

Prepare a 10% by weight NaOH aqueous solution as the etching solution. Furthermore, the solvent used in the preparation of the etching solution, namely water, has a viscosity η of 1.0 mPa·s at 20°C. After the temperature of the etching solution has been adjusted to 75°C, the glass substrate is immersed in the etching solution until the thickness of the glass substrate is reduced by 70 μm. Thereby, the altered part is etched to form a through hole. In this way, a glass substrate with a fine structure of Example 1 was obtained.

<Examples 2-11> Except having changed the etching liquid as shown in Table 3, it carried out similarly to Example 1, and produced the glass substrate with the fine structure of Examples 2-10. Except for the following points, the glass substrate with the fine structure of Example 11 was produced in the same manner as in Example 1. In Example 11, a glass substrate having a thickness of 130 μm and a main surface of 30 mm ² and having the above composition A was used. In addition, a 48% by weight NaOH aqueous solution was used as the etching solution, and the glass substrate was immersed in the etching solution until the thickness of the glass substrate was reduced by 30 μm.

<Example 12> A glass substrate having a thickness of 0.470 mm and a main surface of 30 mm ^{2 was} prepared. The glass forming this glass substrate has the following composition B. (Composition B) Glass type: low alkali glass (aluminum borosilicate glass) Glass composition: SiO ₂ (59 mol%), B ₂ O ₃ (10 mol%), Al ₂ O ₃ (12 mol%) ), TiO ₂ (3 mol%), ZnO (3 mol%), Li ₂ O+Na ₂ O+K ₂ O (4 mol%), MgO+CaO+SrO+BaO (9 mol%)

Except for using the glass substrate having the above composition B, in the same manner as in Example 1, the glass substrate was irradiated with a pulsed laser to form a deteriorated portion.

Prepare a 30% by weight NaOH aqueous solution as the etching solution. After the temperature of the etching solution has been adjusted to 75°C, the glass substrate is immersed in the etching solution until the thickness of the glass substrate is reduced by 70 μm. Thereby, the altered part is etched to form a through hole. In this way, a glass substrate with a fine structure of Example 12 was obtained.

<Example 13> A glass substrate having a thickness of 0.470 mm and a main surface of 30 mm ^{2 was} prepared. The glass forming this glass substrate has the following composition C. (Composition C) Glass type: Low alkali glass (aluminum borosilicate glass) Glass composition: SiO ₂ (54 mol%), B ₂ O ₃ (10 mol%), Al ₂ O ₃ (12 mol%) ), TiO ₂ (3 mol%), ZnO (3 mol%), Li ₂ O+Na ₂ O+K ₂ O (9 mol%), MgO+CaO+SrO+BaO (9 mol%)

Except having used the above-mentioned glass substrate, the glass substrate with the fine structure of Example 13 was obtained in the same manner as in Example 12.

<Example 14> A glass substrate having a thickness of 0.470 mm and a main surface of 30 mm ^{2 was} prepared. The glass forming this glass substrate has the following composition D. (Composition D) Glass type: alkali glass (aluminum borosilicate glass) Glass composition: SiO ₂ (48 mol%), B ₂ O ₃ (10 mol%), Al ₂ O ₃ (12 mol%) , TiO ₂ (3 mol%), ZnO (3 mol%), Li ₂ O+Na ₂ O+K ₂ O (15 mol%), MgO+CaO+SrO+BaO (9 mol%)

Except having used the above-mentioned glass substrate, the glass substrate with the fine structure of Example 14 was obtained in the same manner as in Example 12.

<Comparative Example 1> A glass substrate having a thickness of 2.00 mm and a main surface of 30 mm ^{2 was} prepared. The glass forming the glass substrate has the composition A described above. Except for using this glass substrate, the glass substrate was irradiated with a pulsed laser in the same manner as in Example 1 to form a deteriorated portion.

Prepare a 48% by weight KOH aqueous solution as an etching solution. After the temperature of the etching solution has been adjusted to 100°C, the glass substrate is immersed in the etching solution until the thickness of the glass substrate is reduced by 200 μm. Thereby, the altered part is etched to form a through hole. In this way, a glass substrate with a fine structure of Comparative Example 1 was obtained.

<Comparative Example 2> A glass substrate with a fine structure of Comparative Example 2 was obtained in the same manner as in Example 1 except for the following points. Prepare a mixture of 2 wt% HF aqueous solution and 6 wt% HNO ₃ aqueous solution as the etching solution. After adjusting the temperature of the etching solution to 20°C, immerse the glass substrate in the etching solution until the thickness of the glass substrate is reduced by 65 μm. Thereby, the deformed part is etched. In this way, a glass substrate with a fine structure of Comparative Example 2 was obtained.

<Comparative Example 3> The glass substrate with a fine structure of Comparative Example 3 was obtained in the same manner as in Example 1 except for the following points. Prepare a mixture of 2 wt% HF aqueous solution and 6 wt% HNO ₃ aqueous solution as the etching solution. When the temperature of the etching solution has been adjusted to 20°C and 40 kHz ultrasonic waves are applied to the etching solution, the glass substrate is immersed in the etching solution until the thickness of the glass substrate is reduced by 65 μm. Thereby, the deformed part is etched to form a through hole. In this way, a glass substrate with a fine structure of Comparative Example 3 was obtained.

As shown in Tables 1 and 3, the holes formed in the glass substrates with microstructures of the examples where the characteristic value α of the etching solution containing the alkali etchant is 0.01 or more, satisfies 0.4≦Φ _C /Φ _A ≦1.0 Conditions, the shrinkage of the hole is small. In addition, the holes formed in the glass substrates with microstructures of the examples satisfy the condition of 70°≦θ≦90°, and the holes have high linearity. In addition, the hole formed in the glass substrate with the fine structure of each embodiment satisfies the condition of 0 &lt; D, and there is no ring-shaped recess near the opening of the hole. Furthermore, the arithmetic average roughness Ra of the inner surface of the hole formed on the glass substrate with a fine structure of each example was less than 1 nm, and the inner surface of the hole was in the desired surface state. As shown in Table 3, it shows that if the etching solution further satisfies the condition of 0.04≦α≦0.4, the etching rate will increase, and the productivity of manufacturing a glass substrate with a fine structure can be improved. It means that if the etching solution further satisfies the condition of 0.05≦α≦0.3, the etching rate becomes larger, and the productivity of manufacturing glass substrates with fine structures can be further improved.

According to Comparative Examples 2 and 3, when an acidic etching solution containing hydrofluoric acid is used, if ultrasonic waves are not irradiated, it is difficult to form through holes. According to Comparative Example 3, if an acidic etching solution containing hydrofluoric acid is used for simultaneous ultrasonic irradiation, as shown in Table 1, a ring-shaped recess is formed near the opening of the hole.

In the glass of composition D with a high content of alkali components, the difference between the linear expansion coefficient of the glass and the linear expansion coefficient of silicon is large, and compared with the glass with compositions A, B, and C, it is more resistant to acid And poor alkali resistance.

According to the method of the present invention, even the alkali-free glass with a low etching rate can be manufactured in terms of straightness and flatness of the inner surface of the hole by adjusting the characteristic value α of the etchant. A glass substrate with a hole in the shape and a fine structure. In addition, it means that the linear expansion coefficient of the glass substrate with the fine structure can be matched with the linear expansion coefficient of the silicon substrate, and the required state can be maintained in response to temperature changes. Furthermore, it is shown that it is possible to provide a semiconductor packaging substrate and a manufacturing method thereof that can prevent the alkali component from eluting from a glass substrate with a fine structure and can prevent the diffusion of the alkali component from affecting the electrical characteristics of the product.

[Table 1] Composition of glass Substrate thickness t (L) Aperture Φ _A Aperture Φ _C Φ _C /Φ _A Tilt angle θ Arithmetic average roughness Ra D value D/t Aspect ratio L/Φ _C (Μm) (Μm) (Μm) (°) (Μm) (Μm) Example 1 A 400 66 41 0.62 86.4 0.7 0.5 0.00125 6.1 Example 2 A 400 66 39 0.59 86.1 0.75 0.6 0.00150 6.1 Example 3 A 400 65 38 0.59 86.1 0.75 0.7 0.00175 6.2 Example 4 A 400 65 40 0.61 86.3 0.76 0.8 0.00200 6.2 Example 5 A 400 65 40 0.61 86.3 0.7 0.7 0.00175 6.2 Example 6 A 400 66 41 0.62 86.4 0.74 0.5 0.00125 6.1 Example 7 A 400 66 40 0.60 86.2 0.75 0.6 0.00150 6.1 Example 8 A 400 66 39 0.59 86.1 0.75 0.7 0.00175 6.1 Example 9 A 400 65 38 0.59 86.2 0.78 0.8 0.00200 6.2 Example 10 A 400 65 40 0.61 86.3 0.72 0.7 0.00175 6.2 Example 11 A 100 30 twenty four 0.79 86.4 0.78 0.2 0.00200 3.3 Example 12 B 400 65 38 0.59 86.1 0.75 0.7 0.00175 6.2 Example 13 C 400 65 38 0.59 86.1 0.75 0.7 0.00175 6.2 Example 14 D 400 65 38 0.59 86.1 0.75 0.7 0.00175 6.2 Comparative example 1 A 1800 165 50 0.30 86.3 0.78 0.9 0.00050 10.9 Comparative example 2 A 400 63 0.01 0.01 80.8 1.7 0.3 0.00075 - Comparative example 3 A 400 63 37 0.58 86.2 2.2 -0.4 -0.00100 6.3

[Table 2] Glass composition Alkali component content Li ₂ O+Na ₂ O+K ₂ O (mol%) 0℃～300℃ CTE (G) (×10 ^-7 /K) CTE(G)/CTE(Si) Acid resistance grade Alkali resistance grade A 0 31 0.98 1 1 B 4 38 1.20 1 1 C 9 45 1.42 2 2 D 15 92 2.90 4 3

[table 3] Type of etchant Weight concentration Molar concentration Viscosity η Ion radius r Ion volume Vi Total volume of ionic species Vt Characteristic value α α=η×Vt Etching rate Etching temperature Etching amount (weight%) (Mol/L) (MPa・s) (Nm) (Nm ³ ) (Mol・nm ³ /L) (Mol・nm ³・mPa・s/L) (Μm/hour) (℃) (Μm) Example 1 NaOH 10 2.5 2.5 0.095 0.004 0.009 0.02 0.55 75.0 70.0 Example 2 NaOH 20 5.0 5.0 0.095 0.004 0.018 0.09 0.95 75.0 70.0 Example 3 NaOH 30 7.5 14.0 0.095 0.004 0.027 0.38 0.92 75.0 70.0 Example 4 NaOH 40 10.0 37.0 0.095 0.004 0.036 1.33 0.65 75.0 70.0 Example 5 NaOH 50 12.5 74.0 0.095 0.004 0.045 3.32 0.60 75.0 70.0 Example 6 KOH 10 1.8 0.7 0.133 0.010 0.018 0.01 0.51 75.0 70.0 Example 7 KOH 20 3.6 1.0 0.133 0.010 0.035 0.04 0.84 75.0 70.0 Example 8 KOH 30 5.3 2.0 0.133 0.010 0.053 0.11 1.00 75.0 70.0 Example 9 KOH 40 7.1 4.0 0.133 0.010 0.070 0.28 0.97 75.0 70.0 Example 10 KOH 50 8.9 8.0 0.133 0.010 0.088 0.70 0.77 75.0 70.0 Example 11 KOH 48 8.6 7.9 0.133 0.010 0.084 0.67 0.9 75.0 30.0 Example 12 NaOH 30 7.5 14.0 0.095 0.004 0.027 0.38 1.24 75.0 70.0 Example 13 NaOH 30 7.5 14.0 0.095 0.004 0.027 0.38 1.57 75.0 70.0 Example 14 NaOH 30 7.5 14.0 0.095 0.004 0.027 0.38 2.12 75.0 70.0 Comparative example 1 KOH 48 8.6 7.9 0.133 0.010 0.084 0.67 2.4 100.0 200.0 Comparative example 2 Mixed acid of HF and HNO ₃ HF: 2 HNO ₃ : 6 - - - - - - 43.0 20.0 65.0 Comparative example 3 Mixed acid of HF and HNO ₃ (40 kHz) HF: 2 HNO ₃ : 6 - - - - - - 43.0 20.0 65.0

10: Glass substrate with fine structure 20: Hole 11: First main surface 21: Opening D: Coordinate L1: First contour line L2: Second contour line L3: Third contour line t(L): Substrate thickness Z: Coordinate axis Φ _A : aperture Φc: aperture θ: tilt angle

Fig. 1 is a cross-sectional view schematically showing an example of the glass substrate with a fine structure of the present invention. [FIG. 2] A cross-sectional view schematically showing an example of a glass substrate with a fine structure of a reference example. [Figure 3] A graph showing the relationship between the α value of the etching solution and the etching rate.

10: Glass substrate with fine structure

11: The first main surface

20: hole

D: Coordinate

L1: the first contour line

L2: second contour line

L3: third contour line

t(L): substrate thickness

Z: coordinate axis

Φ _A : Aperture

Φc: Aperture

Claims (7)

A glass substrate with a fine structure, which has a thickness of 50 μm to 2000 μm, and has the following hole: an opening on the first main surface of the glass substrate with a fine structure and the above-mentioned thickness as t State the conditions of (i), (ii), (iii), (iv), and (v), (i) 0.4≦Φ _C /Φ _A ≦1.0, (ii) 70°≦θ≦90°, (iii) ) Ra≦1.0 μm, (iv) 0≦D/t≦0.003, (v) 1.5≦L/Φ _C ≦30, Φ _A is the diameter of the hole of the first main surface, and Φ _C is In the thickness direction of the glass substrate with fine structure, the diameter of the hole at a position equidistant from the first main surface and the end of the hole on the opposite side of the opening, θ is cut along the axis of the hole The size of the angle formed by the first contour line and the second contour line on the cross section of the glass substrate with microstructure, the angle has a size of 90° or less, and the first contour line is derived from the glass substrate with microstructure The center of the thickness direction is formed by the inner surface of the hole extending toward the first main surface, the second contour line is formed by the first main surface, and Ra is in the thickness direction of the glass substrate with fine structure, The arithmetic average roughness of the inner surface of the hole at a position equidistant from the first main surface and the end of the hole on the opposite side is based on the Japanese Industrial Standard (JIS) B 0601:1994, and D is the above When the hole has a ring-shaped peculiar portion formed on the cross section of the third contour line that is outside the first contour line in the radial direction of the hole and connected to the second contour line, it is used along the glass substrate with fine structure The position on the opposite side of the hole that extends in the thickness direction and is farther from the first principal surface than the first principal surface has a positive value in the coordinate axis, which represents the distance from the first principal surface in the thickness direction of the glass substrate with fine structure The coordinates of the position of the farthest ring-shaped peculiar part, L is the length of the hole in the thickness direction of the glass substrate with fine structure. The glass substrate with a fine structure according to claim 1, wherein the sum of the contents of Li ₂ O, Na ₂ O, and K ₂ O is less than 10 mol%. A method of manufacturing a glass substrate with a fine structure, comprising the following steps: a step of irradiating a pulsed laser on the glass substrate to form a deteriorated part, and a step of removing the deteriorated part by wet etching to form a hole in the glass substrate In the above-mentioned wet etching, an alkaline aqueous solution with a characteristic value α of 0.01 or more defined by the following formula (1) is used as the etching solution, α=η×Vt, formula (1), η is the above-mentioned etching solution 20 The viscosity at ℃ [mPa·s], Vt is the product of the molar concentration of alkali ions in the etching solution [mol/L] and the volume Vi [nm ³ ] assuming the alkali ions are spheres. The method for manufacturing a glass substrate with a fine structure according to claim 3, wherein the glass substrate with a fine structure has a thickness of 50 μm to 2000 μm, and the hole is on the first main surface of the glass substrate with a fine structure The first main surface of the glass substrate with fine structure corresponds to the main surface of the glass substrate on which the pulse laser is incident, and the hole satisfies the following (i) and (ii) when the thickness is expressed as t ), (iii), (iv), and (v) conditions, (i) 0.4≦Φ _C /Φ _A ≦1.0, (ii) 70°≦θ≦90°, (iii) Ra≦1.0 μm, ( iv) 0≦D/t≦0.003, (v) 1.5≦L/Φ _C ≦30, Φ _A is the diameter of the hole of the first main surface, Φ _C is the diameter of the glass substrate with fine structure In the thickness direction, the diameter of the hole at a position equidistant from the first main surface and the end opposite to the opening of the hole, θ is obtained by cutting the glass substrate with fine structure along the axis of the hole The size of the angle formed by the first contour line and the second contour line on the appearing cross-section, the angle has a size of 90° or less, and the first contour line is from the center of the thickness direction of the glass substrate with fine structure to the above The first main surface is formed by the inner surface of the hole extending, the second contour line is formed by the first main surface, and Ra is in the thickness direction of the glass substrate with fine structure, and is away from the first main surface and The arithmetic mean roughness of the inner surface of the hole at an equidistant position on the opposite side of the hole is based on the arithmetic average roughness of the Japanese Industrial Standard (JIS) B 0601:1994, D is when the hole is formed on the cross section When the ring-shaped peculiar part of the third contour line that is outside the radius direction of the hole and connected to the second contour line with respect to the first contour line, it extends along the thickness direction of the glass substrate with fine structure and is higher than the above The first main surface is farther away from the end of the hole on the opposite side of the coordinate axis with a positive value, which represents the ring-shaped peculiarity that is farthest from the first main surface in the thickness direction of the glass substrate with fine structure The coordinates of the position of the part, L is the length of the hole in the thickness direction of the glass substrate with fine structure. The method of manufacturing a glass substrate with a fine structure according to claim 3 or 4, wherein the total content of Li ₂ O, Na ₂ O, and K ₂ O in the glass substrate is less than 10 mol%. The method for manufacturing a glass substrate with a fine structure according to any one of claims 3 to 5, wherein the alkaline aqueous solution is potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, or potassium hydroxide aqueous solution and sodium hydroxide aqueous solution The mixture. The method for manufacturing a glass substrate with a fine structure according to any one of claims 3 to 6, wherein the temperature of the alkaline aqueous solution in the wet etching is 60°C to 130°C.

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