WO2020241805A1

WO2020241805A1 - Microstructured glass substrate, electroconductive layer-equipped glass substrate, and microstructured glass substrate production method

Info

Publication number: WO2020241805A1
Application number: PCT/JP2020/021257
Authority: WO
Inventors: 真義山田; 太郎宮内; 輝英井上; 正幸深澤
Original assignee: 日本板硝子株式会社
Priority date: 2019-05-30
Filing date: 2020-05-28
Publication date: 2020-12-03
Also published as: TW202120451A

Abstract

This microstructured glass substrate 10 comprises a flat surface 11a, a hole 20, and a circular protruding portion 15. The flat surface 11a is formed on a first main surface 11 of the microstructured glass substrate 10. The hole 20 opens on the first main surface 11. The circular protruding portion 15 is formed along the opening of the hole 20 on the first main surface 11. In the thickness direction of the microstructured glass substrate 10, the distance D between the flat surface 11a and an end 15e of the protruding portion 15 is such that 0.001 μm ≤ D ≤ 2 μm. The microstructured glass substrate fulfills at least one relationship from among: (i) 0.003 μm ≤ {(Rav)²+(Raf)²}^0.5 ≤ 0.1μm, and (ii) 2 ≤ Rav/Raf ≤ 50. Rav represents the arithmetic mean roughness of the surface from the protruding portion 15. Raf represents the arithmetic mean roughness of the flat surface 11a.

Description

A method for manufacturing a glass substrate with a microstructure, a glass substrate with a conductive layer, and a glass substrate with a microstructure.

The present invention relates to a glass substrate with a microstructure, a glass substrate with a conductive layer, and a method for manufacturing a glass substrate with a microstructure.

In recent years, glass substrates have been attracting attention as one of the substrate materials used together with semiconductors. This is because the glass substrate has advantageous characteristics from the viewpoints of thermal stability, matching with the linear expansion coefficient of the semiconductor, high frequency low loss electrical characteristics, and the like. When a glass substrate is used as a substrate used together with an interposer or a semiconductor, a technique of plating the glass surface with a highly conductive metal or the like is known.

For example, Patent Document 1 describes a method for metallizing the surface of glass, which is applicable in the field of flip-chip glass interposers and the like. The method comprises depositing a layer of metal oxide on at least a portion of the surface of the glass substrate and heating the glass substrate to form an adhesion layer of metal oxide. In addition, this method includes a step of plating a metal on the surface of a glass substrate having an adhesion layer of a metal oxide by a wet chemical plating method, and a step of heating the metal plating layer to a maximum temperature of 150 to 500 ° C. Includes. According to this method, the adhesion promoter of the metal oxide is activated and the metal is plated. High adhesion between the glass substrate and the plated metal layer is provided.

On the other hand, in order to use a glass substrate as a substrate on which a semiconductor or the like is mounted or as a glass interposer, a technique for forming a fine structure such as a hole in the glass substrate is known. For example, in Patent Document 2, a pulsed laser beam is applied to a glass-based substrate to form a damaged region inside the glass-based substrate, and the glass-based substrate is etched in an etching solution to expand the damaged region. A method for forming a predetermined hole in a glass-based substrate is described. In etching, the etching solution is agitated by ultrasonic waves.

Special Table 2016-533429 U.S. Patent Application Publication No. 2018/0068868

According to Patent Document 1, it is necessary to form an adhesion layer of a metal oxide prior to the formation of a metal layer, and the manufacturing process of a glass substrate with a conductive layer is complicated. On the other hand, Patent Document 2 does not specifically study the adhesion of the conductive layer to the glass-based substrate on which a predetermined hole is formed.

Therefore, the present invention provides a glass substrate with a microstructure that is advantageous for forming a conductive layer that adheres well. The present invention also provides a glass substrate with a microstructure and a glass substrate with a conductive layer provided with a conductive layer. Furthermore, the present invention provides a method for producing a glass substrate with a microstructure which is advantageous for forming a conductive layer in good adhesion.

The present invention
A glass substrate with a fine structure
A flat surface formed on the first main surface of the glass substrate with a microstructure,
The hole opened in the first main surface and
It has an annular protrusion formed along the opening of the hole in the first main surface.
The distance D between the flat surface and the end of the protruding portion in the thickness direction of the glass substrate with a microstructure is 0.001 μm ≦ D ≦ 2 μm.
Provided is a glass substrate with a microstructure that satisfies at least one of the following conditions (i) and (ii).
(I) 0.003 μm ≤ {(Rav) ² + (Raf) ² } ^0.5 ≤ 0.1 μm
(Ii) 2 ≦ Rav / Raf ≦ 50
Rav is the arithmetic mean roughness based on Japanese Industrial Standards (JIS) B 0601: 1994 on the surface of the protrusion.
Raf is the arithmetic mean roughness based on the Japanese Industrial Standards (JIS) B 0601: 1994 for the flat surface.

In addition, the present invention
With the above glass substrate with microstructure,
A conductive layer that covers at least a part of the flat surface and at least a part of the inner surface of the hole.
A glass substrate with a conductive layer is provided.

In addition, the present invention
A method of manufacturing a glass substrate with a microstructure.
Irradiating a glass substrate with a pulse laser to form an altered part,
It comprises removing the altered portion by wet etching to form holes in the glass substrate.
The glass substrate with a microstructure is
A flat surface formed on the first main surface of the glass substrate with a microstructure,
The hole opened in the first main surface and
It has an annular protrusion formed along the opening of the hole in the first main surface.
The distance D between the flat surface and the end of the protruding portion in the thickness direction of the glass substrate with a microstructure is 0.001 μm ≦ D ≦ 2 μm.
Provided is a method that satisfies at least one of the following conditions (i) and (ii).
(I) 0.003 μm ≤ {(Rav) ² + (Raf) ² } ^0.5 ≤ 0.1 μm
(Ii) 2 ≦ Rav / Raf ≦ 50
Rav is the arithmetic mean roughness based on Japanese Industrial Standards (JIS) B 0601: 1994 on the surface of the protrusion.
Raf is the arithmetic mean roughness based on the Japanese Industrial Standards (JIS) B 0601: 1994 for the flat surface.

The above-mentioned glass substrate with a fine structure is advantageous for forming a conductive layer that adheres well. In the above glass substrate with a conductive layer, the conductive layer easily adheres well. According to the above method, it is possible to manufacture a glass substrate with a microstructure which is advantageous for forming a conductive layer in good adhesion.

FIG. 1 is a cross-sectional view schematically showing an example of a glass substrate with a microstructure according to the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a glass substrate with a microstructure according to a reference example. FIG. 3 is a cross-sectional view schematically showing an example of a glass substrate with a conductive layer according to the present invention. FIG. 4 is a diagram showing a measurement result of a shape in the vicinity of the opening of the through hole of the glass substrate with a through hole according to the embodiment.

A fine structure such as a through hole or a bottomed hole (non-through hole) is formed on a glass substrate, and a conductive layer such as a metal layer is formed inside the fine structure and on the surface of the glass substrate to form a highly integrated semiconductor mounting substrate or an interposer. It is conceivable to use it. On the other hand, when an electrode or wiring is formed by a conductive layer such as a metal layer on a glass substrate having a fine structure such as a through hole, it is advantageous to improve the adhesion between the conductive layer and the glass. The difference between the coefficient of thermal expansion of glass and the coefficient of thermal expansion of a conductive material such as metal is large, and the conductive layer may peel off from the glass. Therefore, the present inventors have drastically reviewed the structure of the glass substrate with a microstructure in order to improve the adhesion of the conductive layer to the glass substrate with a microstructure. As a result of diligent studies, the present inventors have formed a predetermined annular protrusion along the opening of the hole, and the surface roughness of the flat surface on the first main surface and the surface roughness of the surface of the protrusion have been determined. It was newly found that satisfying a predetermined relationship is advantageous from the viewpoint of enhancing the adhesion of the conductive layer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description relates to an example of the present invention, and the present invention is not limited to the following embodiments.

As shown in FIG. 1, the glass substrate 10 with a microstructure includes a flat surface 11a formed on the first main surface 11, a hole 20, and a protruding portion 15. The hole 20 is open on the first main surface 11. The protruding portion 15 is formed in an annular shape along the opening of the hole 20 on the first main surface 11. The distance D between the flat surface 11a and the end 15e of the protruding portion 15 in the thickness direction of the glass substrate 10 with a microstructure is 0.001 μm ≦ D ≦ 2 μm. The end 15e is the farthest from the flat surface 11a in the thickness direction of the glass substrate 10 with a microstructure in the protruding portion 15. In addition, the glass substrate 10 with a microstructure satisfies at least one of the following conditions (i) and (ii). Rav is the arithmetic mean roughness of the surface of the protrusion 15 based on JIS B 0601: 1994. Raf is the arithmetic mean roughness of the flat surface 11a based on JIS B 0601: 1994.
(I) 0.003 μm ≤ {(Rav) ² + (Raf) ² } ^0.5 ≤ 0.1 μm
(Ii) 2 ≦ Rav / Raf ≦ 50

In the glass substrate 10 with a microstructure, when D is 0.001 μm or more and at least one of the conditions (i) and (ii) is satisfied, a conductive layer is formed on the glass substrate 10 with a microstructure. When you do, the anchor effect is likely to be exhibited properly. Therefore, when the conductive layer is formed so as to cover at least a part of the flat surface 11a and at least a part of the inner surface of the hole 20, the conductive layer tends to adhere well to the glass substrate 10 with a microstructure. In addition, when D is 2 μm or less, it is possible to suppress a decrease in flatness of the main surface of the glass substrate on which wiring or electrodes should be formed. Therefore, the glass substrate 10 with a microstructure is advantageous from the viewpoint of electrical characteristics or integration of the product provided by using the glass substrate 10 with a microstructure. For example, when an electroless plating layer to be a base of a conductive layer is formed by electroless plating, the thickness of the electroless plating layer is usually 1 to 5 μm. When D is 2 μm or less, the thickness of the electroless plating layer tends to be uniform, and defects are unlikely to occur.

FIG. 2 is a cross-sectional view of the glass substrate 100 with a microstructure according to a reference example. The glass substrate 100 with a microstructure is configured in the same manner as the glass substrate 10 with a microstructure, except for a portion to be particularly described. The components of the glass substrate 100 with a microstructure corresponding to the components of the glass substrate 10 with a microstructure are designated by the same reference numerals, and detailed description thereof will be omitted.

The glass substrate 100 with a microstructure does not have an annular protrusion 15, and an annular recess 25 is formed along the opening of the hole 20 in the first main surface 11. Since the glass substrate 100 with a microstructure has an annular recess 25 instead of an annular protrusion 15, it is difficult for the anchor effect to be properly exhibited even if a conductive layer is formed on the glass substrate 100 with a microstructure.

In the glass substrate 10 with a microstructure, the above distance D is preferably 0.001 μm ≦ D ≦ 0.7 μm, and more preferably 0.001 μm ≦ D ≦ 0.1 μm.

When the glass substrate 10 with a microstructure satisfies the condition (i), the anchor effect is more likely to be exhibited more appropriately when the conductive layer is formed on the glass substrate 10 with a microstructure. In addition, it is advantageous that the glass substrate 10 with a microstructure satisfies the condition (i) from the viewpoint of electrical characteristics or integration of the product provided by using the glass substrate 10 with a microstructure.

When the glass substrate 10 with a microstructure satisfies the condition (i), the glass substrate 10 with a microstructure preferably satisfies 0.003 μm ≤ {(Rav) ² + (Raf) ² } ^0.5 ≤ 0.05 μm, and more. Desirably, 0.003 μm ≤ {(Rav) ² + (Raf) ² } ^0.5 ≤ 0.01 μm is satisfied.

When the glass substrate 10 with a microstructure satisfies the condition (i), each of Rav and Raf is not limited to a specific value as long as this condition is satisfied. The Rav is, for example, 0.0015 μm to 0.04 μm, and may be 0.005 μm to 0.03 μm. The Raf is, for example, 0.001 μm to 0.1 μm and may be 0.001 μm to 0.05 μm.

When the glass substrate 10 with a microstructure satisfies the condition (ii), the anchor effect is more likely to be exhibited more appropriately when the conductive layer is formed on the glass substrate 10 with a microstructure.

When the glass substrate 10 with a microstructure satisfies the condition (ii), the glass substrate 10 with a microstructure preferably satisfies 2 ≦ Rav / Raf ≦ 30, and more preferably 2 ≦ Rav / Raf ≦ 20.

When the glass substrate 10 with a microstructure satisfies the condition (ii), each of Rav and Raf is not limited to a specific value as long as this condition is satisfied. The Rav is, for example, 0.001 μm to 0.04 μm, and may be 0.005 μm to 0.03 μm. The Raf is, for example, 0.00025 μm to 0.0025 μm and may be 0.00075 μm to 0.0015 μm.

The glass substrate 10 with a fine structure preferably satisfies the above conditions (i) and (ii). As a result, when the conductive layer is formed on the glass substrate 10 with a microstructure, the anchor effect is more likely to be exhibited more appropriately.

In the cross section that appears by cutting the glass substrate 10 with a microstructure along the axis of the hole 20, the inner surface of the hole 20 extending from the center in the thickness direction of the glass substrate 10 with a microstructure toward the first main surface 11 forms first. The size of the angle of the angle having a size of 90 ° or less formed by the contour line L1 and the second contour line L2 formed by the flat surface 11a is represented by θ. The glass substrate 10 with a microstructure satisfies, for example, the condition of 85 ° ≦ θ ≦ 90 °. In this case, the variation in the hole diameter of the hole 20 is small in the thickness direction of the glass substrate 10 with a microstructure, and the straightness of the hole 20 is high.

The thickness t of the glass substrate 10 with a fine structure is not limited to a specific value. The thickness t is, for example, 50 μm to 2000 μm, and may be 100 μm to 1000 μm.

As shown in FIG. 1, the hole 20 is, for example, a through hole. The hole 20 may be formed as a bottomed hole (non-through hole) that is open only on the first main surface 11.

The diameter Φ _A of the opening of the hole 20 on the first main surface 11 is not limited to a specific value. The diameter Φ _A is, for example, 10 μm to 1000 μm, and may be 50 μm to 500 μm.

In the thickness direction of the glass substrate 10 with a microstructure, the diameter Φ _C of the holes 20 at positions equidistant from the openings of the holes 20 on the first main surface 11 and the holes 20 on the opposite side of the holes 20 is , Not limited to a specific value. The diameter Φ _C is, for example, 5 μm to 1000 μm, and may be 30 μm to 500 μm.

In the glass substrate 10 with the microstructure, the ratio Φ _C / Φ _A in diameter [Phi _C to diameter [Phi _A is not limited to a specific value. Φ _C / Φ _A is, for example, 0.4 to 1.0, and may be 0.5 to 0.9. It should be noted that FIG. 1 clearly shows the aspect of the cross section of the hole 20 when the diameter of the hole 20 varies, including Φ _C and Φ _A , and the aspect in the vicinity of the hole according to the present invention is shown in FIG. It is not limited to the one shown in 1.

The length L of the holes 20 in the thickness direction of the glass substrate 10 with a microstructure is not limited to a specific value. The glass substrate 10 with a microstructure satisfies, for example, the relationship of 1.5 ≦ L / Φ _C ≦ 30. The glass substrate 10 with a microstructure may satisfy the relationship of 2.5 ≦ L / Φ _C ≦ 20.

The glass constituting the glass substrate 10 with a microstructure is not limited to a specific glass. Considering the application to semiconductor mounting, it is desirable that the content of the alkaline component in the glass constituting the glass substrate 10 with a microstructure is low. This is because the coefficient of linear expansion of the glass substrate 10 with a microstructure can be easily brought close to the coefficient of linear expansion of the silicon substrate, and good chemical resistance can be easily realized. In addition, it is possible to prevent the alkaline component contained in the finely structured glass substrate 10 from being eluted and diffused toward the semiconductor element by thermal diffusion or treatment with an acid or alkali. As a result, the electrical insulation is less likely to deteriorate. In addition, electrical characteristics such as dielectric constant (ε) and dielectric loss tangent (tan δ) and high frequency characteristics are less likely to be adversely affected.

From such a viewpoint, the sum of the contents of Li ₂ O, Na ₂ O, and K ₂ O in the glass substrate 10 with a microstructure is preferably less than 0.5 mol%. In this case, the glass substrate 10 with a microstructure tends to have desired characteristics as a substrate for semiconductor mounting. In addition, it is possible to prevent the distance D from becoming too large. In the present specification, glass having a sum of the contents of Li ₂ O, Na ₂ O, and K ₂ O of less than 0.2 mol% is defined as "non-alkali glass", and Li ₂ O, Na ₂ Glass in which the sum of the contents of O and K ₂ O is 0.2 mol% or more and less than 0.5 mol% is defined as “low alkaline glass”. In the present specification, unless otherwise specified, the content of a specific component in glass is expressed by converting the component into an oxide.

Using the glass substrate 10 with a microstructure, for example, the glass substrate 50 with a conductive layer shown in FIG. 3 can be provided. The glass substrate 50 with a conductive layer includes a glass substrate 10 with a microstructure and a conductive layer 30. The conductive layer 30 covers at least a part of the flat surface 11a and at least a part of the inner surface of the hole 20. In the glass substrate 50 with a conductive layer, the conductive layer 30 tends to have high adhesion. Further, although not shown, the hole 20 may be in a form (solid form) filled with a conductive layer 30 or a metal forming another conductive substance or the like.

The conductive layer 30 is, for example, a metal layer. In this case, for example, the conductive layer 30 can be formed by plating. The conductive layer 30 may be a metal layer formed by electroless plating, or may be formed by electroless plating and subsequent electrolytic plating.

The method for manufacturing the glass substrate 10 with a microstructure includes, for example, the following steps (I) and (II).
(I) The glass substrate is irradiated with a pulse laser to form an altered portion.
(II) The portion corresponding to the altered portion is removed by wet etching to form a hole 20 in the glass substrate.

Typically, the etching rate of the etching solution for the altered part of the glass is larger than the etching rate of the etching solution for the unaltered region of the glass.

The steps (I) and (II) are adjusted so that the desired glass substrate 10 with a fine structure can be produced. For example, in step (II), the eluate is produced by etching. A liquid containing a relatively high concentration of eluate will be present from the inside of the hole to the vicinity of the main surface of the glass substrate. Therefore, in the step (II), the etching rate of the portion of the glass substrate corresponding to the vicinity of the hole 20 of the first main surface 11 of the glass substrate 10 with a microstructure becomes the flat surface 11 of the glass substrate 10 with a microstructure. It tends to be lower than the etching rate of the corresponding glass substrate part. As a result, it is considered that the glass substrate 10 with a microstructure has an annular protrusion 15. In addition, in the step (II), a solid substance containing an eluate is likely to be deposited on the portion of the glass substrate corresponding to the vicinity of the hole 20 of the first main surface 11 of the glass substrate 10 with a microstructure. As a result, the annular protrusion 15 is formed on the glass substrate 10 with a microstructure, and the arithmetic mean roughness Rav of the surface of the annular protrusion 15 can be easily adjusted to a desired range.

In particular, when the glass substrate is made of low-alkali glass or non-alkali glass, the content of the alkaline component, which is an easily soluble component, is small in the glass substrate. Therefore, the etching rate of the portion of the glass substrate corresponding to the vicinity of the hole 20 of the first main surface 11 of the glass substrate 10 with a microstructure tends to be further lowered. In this case, for example, the annular protrusion 15 can be appropriately formed on the finely structured glass substrate 10 by suppressing the circulation of the etching solution without applying ultrasonic waves in the step (II). On the other hand, when ultrasonic waves are applied in the step (II), the flow of the etching solution in the portion of the glass substrate corresponding to the vicinity of the hole 20 of the first main surface 11 of the glass substrate 10 with a microstructure and the inside of the hole. The sex improves. As a result, it is presumed that the annular recess 25 is likely to be formed like the glass substrate 100 with a microstructure.

In the step (II), wet etching may be performed using an alkaline etching solution or an acidic etching solution.

The alkaline etching solution is not limited to a specific solution, but is, for example, a potassium hydroxide aqueous solution, a sodium hydroxide aqueous solution, or a mixture of a potassium hydroxide aqueous solution and a sodium hydroxide aqueous solution. In this case, the etching rate tends to be slower than when an acidic etching solution such as hydrofluoric acid is used. Therefore, the reaction species of the etching solution are likely to diffuse into the region away from the main surface of the glass substrate to the inside of the hole. As a result, for example, in the step (II), holes 20 having high straightness are likely to be formed without applying ultrasonic waves.

In the step (II), a surface protective film agent may be applied to one main surface of the glass substrate in order to enable etching from only one side of the glass substrate. As such a surface protective film agent, a commercially available product 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. The etching time is not particularly limited because it depends on the thickness of the glass substrate, but is, for example, 30 to 180 minutes.

The temperature of the etching solution is, for example, 60 ° C to 130 ° C. It is advantageous that the temperature of the etching solution is high in consideration of increasing the moving speed of the reaction species of the etching solution to appropriately diffuse the reaction species so that the reaction species reach the entire altered part and increasing the reaction rate. Is. During the period of step (II), the temperature of the etching solution can be changed to adjust the etching rate. For example, by using a reaction tank made of polytetrafluoroethylene (PTFE) or a reaction tank made of nickel, the temperature of the etching solution can be raised to around 130 ° C. to perform wet etching. On the other hand, it is also possible to use a reaction layer made of heat-resistant vinyl chloride or polyethylene. Heat-resistant vinyl chloride or polyethylene is a versatile material having high chemical resistance and good processability. Therefore, it is easy to reduce the manufacturing cost of the glass substrate 10 with a fine structure. When a reaction layer made of heat-resistant vinyl chloride or polyethylene is used, the temperature of the alkaline aqueous solution is preferably 100 ° C. or lower.

The glass constituting the finely structured glass substrate 10 or the glass constituting the glass substrate used in the above 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 in the above step (I) is 1 to 50 / cm. The central wavelength of the pulsed laser is typically 535 nm or less. The wavelength of the pulsed laser may be, for example, in the range of 350 to 360 nm.

The absorption coefficient a can be calculated by measuring the transmittance and reflectance of a glass substrate having a thickness of t (cm). For a glass substrate with a thickness of t (cm), the transmittance T (%) at a predetermined wavelength (wavelength 535 nm or less) and the reflectance R (%) at an incident angle of 12 ° are measured by a spectrophotometer (for example, JASCO Corporation). It is measured using an ultraviolet-visible near-red spectrophotometer V-670) manufactured by Japan. The absorption coefficient a (/ cm) is calculated from the obtained measured values using the following formula.
a = (1 / t) * ln {(100-R) / T}

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

In the step (I), the pulse laser is usually focused by a lens so as to be focused 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 so as to be focused near the center in the thickness direction of the glass substrate. When processing only the upper surface side of the glass substrate (the incident side of the pulse laser), the pulse laser is usually focused so as to be 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 so as to be focused on the lower surface side of the glass substrate. However, the pulsed laser may be focused on the outside of the glass substrate as long as the altered portion can be formed. For example, the pulse laser may be focused at a position separated from the glass substrate by a predetermined distance (for example, 1.0 mm) from the upper surface or the lower surface of the glass substrate. In other words, as long as the altered part can be formed on the glass substrate, the pulse laser is located within 1.0 mm from the upper surface of the glass substrate in the front direction (the direction opposite to the traveling direction of the pulse laser) (upper surface of the glass substrate). (Including), or may be focused at a position (including the lower surface position of the glass substrate) within 1.0 mm behind the lower surface of the glass substrate (direction in which the pulsed laser transmitted through the glass travels) or 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. Further, if the pulse width is larger than 200 ns, the peak value of the pulse laser is lowered, and the processing may not be successful. The glass substrate is irradiated with a laser beam having an energy of 5 to 100 μJ / pulse. By increasing the energy of the pulsed laser, it is possible to increase the length of the altered portion in proportion to it. The beam quality M ₂ value of the pulsed laser may be, for example, 2 or less. By using a pulsed laser having an M ₂ value of 2 or less, the formation of minute pores or minute grooves becomes easy.

In the step (I), the pulsed laser may be a harmonic of an Nd: YAG laser, a harmonic of an Nd: YVO ₄ laser, or a harmonic of an Nd: YLF laser. The harmonics are, for example, second harmonics, third harmonics, or fourth harmonics. The wavelength of the second harmonic of these lasers is in the vicinity of 532 to 535 nm. The wavelength of the third harmonic is in the vicinity of 355 to 357 nm. The wavelength of the 4th harmonic is in the vicinity of 266 to 268 nm. By using these lasers, a glass substrate can be processed at low cost.

Examples of the apparatus used for laser processing applied to the step (I) include a high-repetition solid-state pulse UV laser manufactured by Coherent: AVIA355-4500. In this apparatus, it is a third harmonic Nd: YVO ₄ laser, and a maximum laser power of about 6 W can be obtained when the repetition frequency is 25 kHz. The wavelength of the third harmonic is 350 to 360 nm.

In a typical optical system, the oscillated laser is spread 2 to 4 times with a beam expander (at this point φ7.0 to 14.0 mm), the central part of the laser is cut off with a variable iris, and then the galvanometer mirror. Adjust the optical axis with, and focus on the glass substrate while adjusting the focal position with an fθ lens of about 100 mm.

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

Further, the beam diameter S (mm) of the pulse laser is, for example, in the range of 1 to 40 mm, and may be selected from the range of 3 to 20 mm. Here, the beam diameter S is the beam diameter of the pulsed laser when it is incident on the lens, and means the diameter in the range where the intensity is [1 / e ² ] times the intensity of the center of the beam.

In the step (I), the value obtained by dividing the focal length P by the beam diameter S, that is, the value of [P / S] is 7 or more, preferably 7 or more and 40 or less, and 10 or more and 20 or less. May be good. This value is related to the light-collecting property of the laser irradiated on the glass, and the smaller this value is, the more the laser is locally focused, and it becomes difficult to prepare a uniform and long altered part. .. If this value is less than 7, the laser power becomes too strong in the vicinity of the beam waist, causing a problem that cracks are likely to occur inside the glass substrate.

In the step (I), pretreatment on the glass (for example, forming a film that promotes absorption of the pulse laser) is not required before irradiation with the pulse laser. However, such processing may be performed.

The numerical aperture (NA) may be varied from 0.020 to 0.075 by changing the size of the iris and changing the laser diameter. If the NA becomes too large, the laser energy is concentrated only in the vicinity of the focal point, and the altered portion may not be effectively formed in the thickness direction of the glass substrate. Therefore, adjustment is performed each time within the above range.

Furthermore, by irradiating a pulse laser with a small NA, a relatively long altered part is formed in the thickness direction by one pulse irradiation, which is effective in improving the tact time.

It is preferable to irradiate the sample with a laser with a repetition frequency of 10 to 25 kHz. Further, by changing the focal position in the thickness direction of the glass substrate, the position (upper surface side or lower surface side) of the altered portion formed on the glass substrate can be optimally adjusted.

Furthermore, the laser output, the operation of the galvanometer mirror, etc. can be controlled by the control from the control PC, and the laser is irradiated onto the glass substrate at a predetermined speed based on the two-dimensional drawing data created by CAD software or the like. Can be done.

A deteriorated part different from other parts of the glass substrate is formed in the part irradiated with the laser. This altered part can be easily identified by an optical microscope or the like. Although there are differences depending on the composition of each glass, the altered portion is formed in a generally columnar shape. The altered portion can reach from the vicinity of the upper surface to the vicinity of the lower surface of the glass substrate.

The altered part is a sparse glass in a high temperature range caused by a photochemical reaction caused by laser irradiation and a defect such as an E'center or non-crosslinked oxygen, or a rapid heating or cooling caused by laser irradiation. It is considered to be the part that retained the structure.

In the conventional processing method using the femtosecond laser device, the altered part is formed while scanning the laser in the depth direction (thickness direction of the glass substrate) so that the irradiation pulses overlap. On the other hand, according to the manufacturing method in which the laser irradiation and the wet etching according to the step (I) of the present invention are used in combination, the altered portion can be formed by a single pulse laser irradiation.

The conditions selected in the step (I) are, for example, an absorption coefficient of glass of 1 to 50 / cm, a pulse laser width of 1 to 100 ns, and a pulse laser energy of 5 to 1000 μJ / pulse. Examples thereof include a combination in which the wavelength is 350 to 360 nm, the beam diameter S of the pulse laser is 3 to 20 mm, and the focal distance P of the lens is 100 to 200 mm.

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

The size of the altered portion formed in the step (I) changes depending on the beam diameter S of the laser when it is incident on the lens, the focal length P of the lens, the absorption coefficient of the glass, the power of the pulse laser, and the like. The obtained altered portion has, for example, a diameter of about 5 to 200 μm and may be about 10 to 150 μm. The depth of the altered portion varies depending on the above laser irradiation conditions, the absorption coefficient of glass, and the plate thickness of glass, but may be, for example, about 50 to 2000 μm.

Further, the method of forming the altered portion is not limited to the above mode. For example, the altered portion or the machined hole may be formed by irradiation from the femtosecond laser device described above.

The optical system for irradiating the pulse laser may be an optical system equipped with an axicon lens. A Bessel beam can be formed by condensing a laser beam using such an optical system. For example, it is possible to obtain a Bessel beam in which the light intensity at the central portion is maintained high at a length of several mm to several tens of mm in the optical axis direction of the irradiation position of the pulse laser. As a result, the depth of focus can be increased and the beam diameter can be reduced. As a result, a substantially uniform altered portion can be formed in the thickness direction of the glass substrate.

The glass constituting the glass substrate 10 with a microstructure or the glass constituting the glass substrate used in the above manufacturing method may be quartz glass, borosilicate glass, aluminosilicate glass, sodalime glass, or titanium-containing silicate glass. Good. The glass constituting the glass substrate 10 with a microstructure or the glass constituting the glass substrate used in the above-mentioned manufacturing method is preferably non-alkali glass or low-alkali glass among these glasses.

In order to further effectively increase the above absorption coefficient, the glass contains at least one oxide of a metal selected from Bi, W, Mo, Ce, Co, Fe, Mn, Cr, V, and Cu as a coloring component. It may contain seeds.

As borosilicate glass, Corning's # 7059 glass (composition is expressed in% by mass, SiO ₂ 49%, Al ₂ O ₃ 10%, B ₂ O ₃ 15%, RO (alkaline earth metal oxide)) 25%) or Pyrex® (glass code 7740) and the like.

A first example of an aluminosilicate glass may have the following composition.
Expressed in% by mass,
SiO ₂ 50-70%,
Al ₂ O ₃ 14-28%,
Na ₂ O 1-5%,
MgO 1-13% and ZnO 0-14%,
A glass composition containing.

A second example of an aluminosilicate glass may have the following composition.
Expressed in% by mass,
SiO ₂ 56-70%,
Al ₂ O ₃ 7-17%,
_{_{B 2 O 3 0 ~ 9%}} ,
Li ₂ O 4-8%,
MgO 1-11%,
ZnO 4-12%,
TiO ₂ 0 ~ _2%,
Li ₂ O + MgO + ZnO 14-23%,
CaO + BaO 0-3%,
A glass composition containing.

A third example of an aluminosilicate glass may have the following composition.
Expressed in% by mass,
SiO ₂ 58-66%,
Al ₂ O ₃ 13-19%,
Li ₂ O 3 to 4.5%,
Na ₂ O 6-13%,
K ₂ O 0-5%,
R ₂ O 10-18% (however, R ₂ O = Li ₂ O + Na ₂ O + K ₂ O),
MgO 0-3.5%,
CaO 1-7%,
SrO 0-2%,
BaO 0-2%,
RO 2-10% (however, RO = MgO + CaO + SrO + BaO),
TiO ₂ 0 ~ _2%,
CeO ₂ 0 ~ _2%,
_{_{Fe 2 O 3 0 ~ 2%}} ,
MnO 0 to 1% (however, TiO ₂ + CeO ₂ + Fe ₂ O ₃ + MnO = 0.01 to 3%),
SO ₃ 0.05-0.5%,
A glass composition containing.

A fourth example of an aluminosilicate glass may have the following composition.
Expressed in% by mass,
SiO ₂ 60-70%,
Al ₂ O ₃ 5-20%,
Li ₂ O + Na ₂ O + K ₂ O 5-25%,
Li ₂ O 0 to 1%,
Na ₂ O 3-18%,
K ₂ O 0-9%,
MgO + CaO + SrO + BaO 5-20%,
MgO 0-10%,
CaO 1-15%,
SrO 0-4.5%,
BaO 0 to 1%,
TiO ₂₀ to 1%,
ZrO ₂ 0 ~ 1%,
A glass composition containing.

A fifth example of an aluminosilicate glass may have the following composition.
Shown in% by mass,
SiO ₂ 59-68%,
Al ₂ O ₃ 9.5 to 15%,
Li ₂ O 0 to 1%,
Na ₂ O 3-18%,
K ₂ O 0-3.5%,
MgO 0-15%,
CaO 1-15%,
SrO 0-4.5%,
BaO 0 to 1%,
TiO ₂ 0 ~ _2%,
ZrO ₂ 1-10%,
A glass composition containing.

Soda lime glass is, for example, a glass composition widely used for flat glass.

The first example of titanium-containing silicate glass may have the following composition.
Display in mol%,
Comprises TiO ₂ 5 ~ 25%,
SiO ₂ + B ₂ O ₃ 50-79%,
Al ₂ O ₃ + TiO ₂ 5-25%,
Li ₂ O + Na ₂ O + K ₂ O + Rb ₂ O + Cs ₂ O + MgO + CaO + SrO + BaO 5-20%,
Is a glass composition.

Further, in the first example of the titanium-containing silicate glass described above,
SiO ₂ 60-65%,
TiO ₂ 12.5 to 15%,
Contains Na ₂ O 12.5-15%,
SiO ₂ + B ₂ O ₃ 70-75%,
Is preferable.

Furthermore, in the first example of the titanium-containing silicate glass described above,
(Al ₂ O ₃ + TiO ₂ ) / (Li ₂ O + Na ₂ O + K ₂ O + Rb ₂ O + Cs ₂ O + MgO + CaO + SrO + BaO) ≤0.9,
Is more preferable.

In addition, the second example of the titanium-containing silicate glass may have the following composition. Display in mol%,
B ₂ O ₃ 10-50%,
Includes TiO ₂ 25-40%,
SiO ₂ + B ₂ O ₃ 20-50%,
Li ₂ O + Na ₂ O + K ₂ O + Rb ₂ O + Cs ₂ O + MgO + CaO + SrO + BaO 10-40%,
Is a glass composition.

The first example of low alkaline glass may have the following composition.
Display in mol%,
SiO ₂ 45-68%,
B ₂ O ₃ 2-20%,
Al ₂ O ₃ 3-20%,
TiO ₂ 0.1-5.0% (excluding 5.0%),
Contains ZnO 0-9%,
A glass composition containing Li ₂ O + Na ₂ O + K ₂ O 0 to 0.5% (excluding 0.5%).

Further, in the first example of the low alkaline glass described above, as a coloring component,
CeO ₂ 0 ~ 3%,
Fe ₂ O ₃₀ to 1%,
Is preferably included. Non-alkali glass is more preferable.

The first example above of low alkaline or non-alkali glass comprises TiO ₂ as an essential component. The content of TiO ₂ in the above first example of low-alkali glass or non-alkali glass is 0.1 mol% or more and less than 5.0 mol%, and the smoothness of the inner wall surface of the hole obtained by laser irradiation is excellent. From the point of view, it is preferably 0.2 to 4.0 mol%, more preferably 0.5 to 3.5 mol%, and even more preferably 1.0 to 3.5 mol%. Appropriate inclusion of TiO ₂ in low-alkali glass or non-alkali glass having a specific composition makes it possible to form an altered portion even by energy irradiation such as a relatively weak laser, and the altered portion is further subjected to a post-process. It has the effect that it can be removed more easily when etching is performed. In addition, TiO ₂ has a binding energy that is substantially the same as that of ultraviolet light, and absorbs ultraviolet light. By appropriately containing TiO ₂ , it is possible to control the coloring by utilizing the interaction with other colorants as charge transfer absorption. Therefore, by adjusting the content of TiO _2, the absorption of a predetermined light can be made appropriate. When the glass has an appropriate absorption coefficient, it becomes easy to form an altered portion in which holes are formed by etching. Therefore, from these viewpoints as well, it is preferable to appropriately contain TiO ₂ .

Further, the above-mentioned first example of low-alkali glass or non-alkali glass may contain ZnO as an optional component. In this case, the ZnO content is preferably 0 to 9.0 mol%, more preferably 1.0 to 8.0 mol%, and even more preferably 1.5 to 5.0 mol%. , Particularly preferably 1.5-3.5 mol%. ZnO is a component that absorbs ultraviolet light in the ultraviolet light region like TiO _2, and ZnO is contained in the glass constituting the finely structured glass substrate 10 or the glass forming the glass substrate used in the above manufacturing method. It has an effective effect on glass.

The above first example of low-alkali glass or non-alkali glass may contain CeO ₂ as a coloring component. In particular, by using CeO ₂ in combination with TiO ₂ , the altered portion can be formed more easily. The content of CeO ₂ in the above first example of low alkaline glass or non-alkali glass is preferably 0 to 3.0 mol%, more preferably 0.05 to 2.5 mol%, and further. It is preferably 0.1 to 2.0 mol%, and particularly preferably 0.2 to 0.9 mol%.

Fe ₂ O _{3 is} also effective as a coloring component in the glass constituting the finely structured glass substrate 10 or the glass forming the glass substrate used in the above-mentioned manufacturing method, and the glass constituting the finely structured glass substrate 10 or the above-mentioned production. The glass forming the glass substrate used in the method may contain Fe ₂ O ₃ . In particular, by using TiO ₂ and Fe ₂ O ₃ in combination, or by using TiO ₂ , CeO ₂ , and Fe ₂ O ₃ in combination, the formation of the altered portion becomes easy. The content of Fe ₂ O ₃ in the low-alkali glass or the non-alkali glass is preferably 0 to 1.0 mol%, more preferably 0.008 to 0.7 mol%, and even more preferably 0.01. It is ~ 0.4 mol%, and particularly preferably 0.02 to 0.3 mol%.

In the above first example of low-alkali glass or non-alkali glass, the absorption coefficient of a predetermined wavelength (wavelength 535 nm or less) of the glass is 1 due to the inclusion of an appropriate coloring component, although not limited to the components listed above. It may be up to 50 cm ^-1 , preferably 3 to 40 cm ^-1 .

In addition, the second example of low alkaline glass may have the following composition.
Display in mol%,
SiO ₂ 45-70%,
B ₂ O ₃ 2-20%,
Al ₂ O ₃ 3-20%,
CuO 0.1-2.0%,
TiO ₂₀ to 15.0%,
ZnO 0-9.0%,
A glass composition containing Li ₂ O + Na ₂ O + K ₂ O 0 to 0.5% (excluding 0.5%).
Further, non-alkali glass is more preferable.

The above-mentioned second example of the low-alkali glass or the non-alkali glass may contain TiO ₂ like the above-mentioned first example of the low-alkali glass or the non-alkali glass. The content of TiO ₂ in the above second example of the low-alkali glass or the non-alkali glass is 0 to 15.0 mol%, which is desirable from the viewpoint of excellent smoothness of the inner wall surface of the hole obtained by laser irradiation. It is 0 to 10.0 mol%, more preferably 1 to 10.0 mol%, further preferably 1.0 to 9.0 mol%, and particularly preferably 1.0 to 5.0 mol%. Is.

Moreover, the above-mentioned second example of low-alkali glass or non-alkali glass may contain ZnO. The ZnO content of the low-alkali glass or non-alkali glass in the second example above is 0 to 9.0 mol%, preferably 1.0 to 9.0 mol%, more preferably 1.0. ~ 7.0 mol%. Since ZnO is a component that absorbs ultraviolet light in the ultraviolet light region like TiO ₂ , if ZnO is contained, it forms a glass constituting the finely structured glass substrate 10 or a glass substrate used in the above manufacturing method. It has an effective effect on glass.

Furthermore, the above second example of low-alkali glass or non-alkali glass comprises CuO. The content of CuO in the above second example of the low alkaline glass or the non-alkali glass is preferably 0.1 to 2.0 mol%, more preferably 0.15 to 1.9 mol%. More preferably, it is 0.18 to 1.8 mol%, and particularly preferably 0.2 to 1.6 mol%. The inclusion of CuO in the second example of low alkaline or non-alkali glass above causes the glass to be colored, allowing the absorption coefficient at a given laser wavelength to be adjusted to an appropriate range and the energy of the irradiating laser. Can be properly absorbed. As a result, the altered portion that is the basis of pore formation can be easily formed.

In the above second example of low-alkali glass or non-alkali glass, the absorption coefficient of a predetermined wavelength (wavelength 535 nm or less) of the glass is 1 due to the inclusion of an appropriate coloring component, although not limited to the components listed above. It may be up to 50 cm ^-1 , preferably 3 to 40 cm ^-1 .

The above first and second examples of low-alkali glass or non-alkali glass may contain MgO as an optional component. Among alkaline earth metal oxides, MgO has a feature of suppressing an increase in the coefficient of thermal expansion and not excessively lowering the strain point, and also improves solubility. The content of MgO in the above first and second examples of low-alkali glass or non-alkali glass is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, and further. It is preferably 10.0 mol% or less, and particularly preferably 9.5 mol% or less. The MgO content of the low-alkali glass or non-alkali glass in the first and second examples above is preferably 2.0 mol% or more, and more preferably 3.0 mol% or more. More preferably, it is 4.0 mol% or more, and particularly preferably 4.5 mol% or more.

The above-mentioned first example and second example of low-alkali glass or non-alkali glass may contain CaO as an optional component. Like MgO, CaO has a feature of suppressing an increase in the coefficient of thermal expansion and not excessively lowering the strain point, and also improves solubility. The CaO content of the low-alkali glass or non-alkali glass in the above first and second examples is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, and further. It is preferably 10.0 mol% or less, and particularly preferably 9.3 mol% or less. The CaO content of the low-alkali glass or non-alkali glass in the first and second examples above is preferably 1.0 mol% or more, and more preferably 2.0 mol% or more. More preferably, it is 3.0 mol% or more, and particularly preferably 3.5 mol% or more.

The above-mentioned first example and second example of low-alkali glass or non-alkali glass may contain SrO as an optional component. Similar to MgO and CaO, SrO has the characteristics of suppressing an increase in the coefficient of thermal expansion and not excessively lowering the strain point, and also improves solubility, thus improving devitrification characteristics and acid resistance. For this purpose, it may be contained in the glass constituting the finely structured glass substrate 10 or the glass forming the glass substrate used in the above-mentioned manufacturing method. The content of SrO in the above first and second examples of low-alkali glass or non-alkali glass is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, and further. It is preferably 10.0 mol% or less, and particularly preferably 9.3 mol% or less. Further, the content of SrO in the above-mentioned first example and second example of the low-alkali glass or the non-alkali glass is preferably 1.0 mol% or more, and more preferably 2.0 mol% or more. More preferably, it is 3.0 mol% or more, and particularly preferably 3.5 mol% or more.

As used herein, "substantially free" of a component means that the content of the component in the glass is less than 0.1 mol%, preferably less than 0.05 mol%, more preferably 0.01 mol. It means that it is less than%. In this specification, the upper limit value and the lower limit value of the numerical range (content of each component, value calculated from each component, each physical property, etc.) can be appropriately combined.

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

The coefficient of thermal expansion of the glass constituting the glass substrate 10 with a fine structure or the glass forming the glass substrate used in the above manufacturing method is measured as follows, for example. First, a cylindrical glass sample having a diameter of 5 mm and a height of 18 mm is prepared. The coefficient of thermal expansion is calculated by heating this from 25 ° C. to the yield point of the glass sample and measuring the elongation of the glass sample at each temperature. The average value of the coefficient of thermal expansion in the range of 50 to 350 ° C. can be calculated to determine the average coefficient of thermal expansion.

In the above step (I), it is not necessary to use so-called photosensitive glass, and the range of glass that can be processed is wide. That is, in the step (I) described above, glass that is substantially free of gold or silver can be processed.

Particularly highly rigid glass is less likely to crack on both the upper surface and the lower surface of the glass when irradiated with a laser, and can be suitably processed in the above step (I). Therefore, the Young's modulus of the glass constituting the glass substrate 10 with a microstructure or the glass forming the glass substrate used in the above-mentioned manufacturing method is preferably 80 GPa or more.

The glasses listed above may be commercially available and can be purchased and obtained. Even if this is not the case, the desired glass can be produced by a known molding method (for example, overflow method, float method, slit draw method, casting method, etc.), and further by post-processing such as cutting or polishing. A glass composition having a desired shape can be obtained.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples. First, an evaluation method relating to Examples and Comparative Examples will be described.

<Thickness>
Using a micrometer (manufactured by Mitutoyo, product name: IP54), the thickness of the glass substrate before and after wet etching was measured in each Example and Comparative Example. The etching amount was obtained by subtracting the thickness of the glass substrate after the wet etching from the thickness of the glass substrate before the wet etching. The results are shown in Table 1.

<Evaluation of shape>
Using an optical surface texture measuring machine (manufactured by Zygo, product name: NEW VIEW 5000), the glass substrate with through holes according to each example and comparative example, and the glass after removing the conductive layer from the glass substrate with conductive layer. The height D of the peripheral portion of one opening of the through hole, the arithmetic mean roughness Rav of the surface of the peripheral portion of one opening of the through hole, and the arithmetic mean of the flat portion on the main surface of the glass substrate with respect to the substrate. Roughness Raf was measured. FIG. 4 is a diagram showing an example of the measurement result of the surface shape of the glass substrate by the optical surface property measuring machine. The height D of the peripheral portion of one opening of the through hole is the glass at an intermediate position at approximately the same distance from the center of each opening of the two adjacent through holes when the glass substrate including the opening is viewed in a plan view. It was determined based on the height of the main surface of the substrate. The arithmetic mean roughness Rav of the surface around one opening of the through hole is measured in the plan view of the glass substrate, where the height of the annular protrusion around one opening of the through hole is maximized. Was performed for a range of 5 μm in the radial direction of the opening with reference to. In addition, the arithmetic mean roughness Raf of the flat portion on the main surface of the glass substrate was measured with respect to the main surface of the glass substrate at an intermediate position at approximately equal distances from the openings of the two adjacent through holes. The results are shown in Tables 2 and 3.

Glass with through holes from the measurement results of the surface shape of the glass substrate with through holes according to each example and comparative example obtained by using an optical surface property measuring machine (manufactured by Zygo, product name: NEWVIEW5000). The hole diameter of the through hole on one main surface of the substrate was determined. The results are shown in Table 1.

The glass substrate with through holes or the glass substrate with a conductive layer according to each example and each comparative example was cut to expose the inner surface of the holes, and the surface exposed by the cut was polished. Polishing was performed so that the surface obtained by polishing could be regarded as a flat surface including the axis of the hole. Observe the surface obtained by polishing, and on that surface, the contour line formed by the inner surface of the hole extending from the center in the thickness direction of the glass substrate toward one main surface of the glass substrate and the flat portion of the main surface of the glass substrate. The size of the angle (taper angle) θ having a size of 90 ° or less formed by the contour line formed by the glass was determined. The results are shown in Tables 2 and 3.

<Adhesion test>
Through holes are formed on the main surface of the glass substrate so that openings are formed at intervals of 25 μm × 25 μm in the directions orthogonal to each other, and a conductive layer is formed on the main surface of the substrate including the openings of those holes. With respect to the glass substrate with a conductive layer according to each of the Examples and Comparative Examples, the 10 mm square portion of the conductive layer was spaced 1 mm in each of the vertical and horizontal directions orthogonal to each other so as not to overlap the opening of the hole. Cuts were made in a grid pattern to provide 10 × 10 = 100 compartments. Attach 12 mm wide cellophane tape (manufactured by Nichiban Co., Ltd., product name: Cellotape No. 405, "Cellotape" is a registered trademark of Nichiban Co., Ltd.) to the notched part so as to completely cover the above 100 sections. , The cellophane tape was pressed from above for 15 seconds. Then, the cellophane tape was peeled off, and the number of sections where the conductive layer was peeled off was counted at that site. For each glass substrate with a conductive layer, this work was repeated 5 times, and the ratio of the total number of compartments from which the conductive layer was peeled off to the total number of compartments Nt = 100 × 5 = 500 by 5 tests (Np / Nt). [%] Was determined as the survival rate. The results are shown in Table 3.

<Examples and Comparative Examples>
(Glass substrate)
As shown in Table 1, a glass substrate having a thickness of 220 μm, 455 μm, 465 μm, 815 μm, or 1350 μm and having a size of 30 mm square in a plan view was prepared. The glass forming the glass substrate was non-alkali glass (aluminoborosilicate glass) and had the following glass composition.
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%)

(Laser irradiation conditions)
In each of the Examples and Comparative Examples, pulse irradiation was performed at intervals of 250 μm on a 10 mm square portion of the central portion of the glass substrate under the following conditions to form an altered portion in the thickness direction of the glass.
Pulsed laser wavelength: 355 nm
Pulsed laser irradiation energy: 500 μJ / pulse

(Wet etching)
The glass substrate on which the altered portion was formed was put into the etchant, and the thickness of each glass substrate was adjusted so as to have the values shown in Table 1. Table 1 shows the main components of each etchant (aqueous solution) used for wet etching in each Example and Comparative Example. In each Example and Comparative Example, 500 g of the predetermined etchant shown in Table 1 was prepared, the etchant was placed in a 1 L (liter) polyethylene beaker, and the temperature of the etchant was the etching temperature shown in Table 1 using a water bath. Adjusted to be kept at. In each of the examples and comparative examples, holes were formed through the glass substrate in the thickness direction. In this way, a glass substrate with a through hole according to each Example and Comparative Example was obtained.

(Plating process)
The glass substrates with through holes according to each Example and Comparative Example were placed in a 10% by weight aqueous solution of potassium hydroxide (KOH) and degreased for 1 minute. Then, a glass substrate with through holes was subjected to predip and activator treatment using a solution prepared by mixing Sulcup PED-104 with pure water at a concentration of 25% by weight and using a solution at 25 ° C. Then, a glass substrate with through holes was treated with a solution prepared by mixing Sulcup Accelerator ALF-406-A with pure water at a concentration of 15% by weight and using a solution at 25 ° C. Then, 50 mL of Sulcup PEA-40-M, 30 mL of Sulcup PEA-40-B, 17.5 mL of Sulcup PEA-40-D, and 11.5 mL of formaldehyde solution (37%) (manufactured by Kishida Chemical Co., Ltd.) were added. An electroless copper plating treatment was performed on a glass substrate with through holes using a solution prepared by mixing with 300 mL of pure water. After that, the glass substrate with through holes was washed with pure water and further dried at 80 ° C. for about 1 hour to obtain a glass substrate with a conductive layer according to each Example and Comparative Example. The thickness of the obtained electroless copper plating film (conductive layer) was 5 μm. Sulcup PED-104, Sulcup Accelerator ALF-406-A, Sulcup PEA-40-M, Sulcup PEA-40-B, and Sulcup PEA-40-D are products of C. Uyemura & Co., Ltd. Is a registered trademark of C. Uyemura & Co., Ltd.

(Removal of conductive layer)
Using a 1 L mixed aqueous solution of paranitrobenzoic acid and diethylenetriamine (paranitrobenzoic acid concentration: 80 g / L, diethylenetriamine concentration: 200 g / L), the temperature of the mixed aqueous solution was adjusted to 75 ° C., and each Example and Comparative Example The electroless copper plating film on the glass substrate with the conductive layer according to the above was dissolved and removed. In this way, the conductive layer was removed from the glass substrate with the conductive layer according to each Example and Comparative Example.

As shown in Table 2, in the glass substrate with through holes according to each embodiment, the height D of the peripheral portion was within the range of 0.008 μm to 1.900 μm. Further, as shown in Table 3, the value of the height D of the peripheral portion of the glass substrate after removing the conductive layer from the glass substrate with the conductive layer according to each embodiment is the value of the height D of the peripheral portion in the glass substrate with through holes according to each embodiment. It was almost the same as the value of the height D of the peripheral portion. On the other hand, the glass substrate with through holes according to Comparative Example 1 did not have an annular protrusion, and the height D of the peripheral portion of the glass substrate with through holes according to Comparative Example 1 was 0 μm.

In the glass substrates with through holes according to Examples 1 to 9, the value of {(Rav) ² + (Raf) ² } ^0.5 was within the range of 0.005 μm to 0.05 μm. The value of {(Rav) ² + (Raf) ² } ^0.5 in the glass substrate after removing the conductive layer from the glass substrate with the conductive layer according to Examples 1 to 9 is within the range of 0.004 μm to 0.04 μm. Was there. On the other hand, the value of {(Rav) ² + (Raf) ² } ^{0.5 in} the glass substrate with a through hole according to Comparative Example 1 and the glass substrate with a conductive layer after removing the conductive layer according to Comparative Example 1 is It was 0.001 μm.

In the glass substrate with through holes according to Examples 1 to 10, the Rav / Raf value was within the range of 2 to 25. The Rav / Raf value in the glass substrate after removing the conductive layer from the glass substrate with the conductive layer according to Examples 1 to 10 was within the range of 2 to 30. On the other hand, the Rav / Raf value in the glass substrate with a through hole according to Comparative Example 1 and the glass substrate with a conductive layer after removing the conductive layer from the glass substrate with a conductive layer according to Comparative Example 1 was 0.6.

As shown in Table 3, the residual rate is high in the adhesion test of the glass substrate with the conductive layer according to Examples 1 to 10, and the adhesion of the conductive layer of the glass substrate with the conductive layer according to Examples 1 to 10 is good. It has been suggested. On the other hand, the residual rate was low in the adhesion test of the glass substrate with a conductive layer according to Comparative Example 1, and the adhesion of the conductive layer of the glass substrate with a conductive layer according to Comparative Example 1 was inferior to that of Examples 1 to 10. It was suggested that there was. The value of the height D of the peripheral portion of the glass substrate with through holes and the value of {(Rav) ² + (Raf) ² } ^0.5 or the value of Rav / Raf according to Examples 1 to 10 are the adhesion of the conductive layer. It is considered that it was advantageous in enhancing the sex.

Claims

A glass substrate with a fine structure
A flat surface formed on the first main surface of the glass substrate with a microstructure,
The hole opened in the first main surface and
It has an annular protrusion formed along the opening of the hole in the first main surface.
The distance D between the flat surface and the end of the protruding portion in the thickness direction of the glass substrate with a microstructure is 0.001 μm ≦ D ≦ 2 μm.
A glass substrate with a microstructure that satisfies at least one of the following conditions (i) and (ii).
(I) 0.003 μm ≤ {(Rav) 2 + (Raf) 2 } 0.5 ≤ 0.1 μm
(Ii) 2 ≦ Rav / Raf ≦ 50
Rav is the arithmetic mean roughness based on Japanese Industrial Standards (JIS) B 0601: 1994 on the surface of the protrusion.
Raf is the arithmetic mean roughness based on the Japanese Industrial Standards (JIS) B 0601: 1994 for the flat surface.
The glass substrate with a microstructure according to claim 1, which satisfies the conditions of (i) and (ii) above.
In a cross section that appears by cutting the glass substrate with a microstructure along the axis of the hole, the inner surface of the hole extending from the center in the thickness direction of the glass substrate with the microstructure toward the first main surface forms first. Claim 1 or 2 that satisfies 85 ° ≤ θ ≤ 90 ° when the size of the angle of the angle having a size of 90 ° or less formed by the contour line and the second contour line formed by the flat surface is expressed as θ. The glass substrate with a microstructure described in.
The finely structured glass substrate according to any one of claims 1 to 3, wherein the sum of the contents of Li 2 O, Na 2 O, and K 2 O is less than 0.5 mol%.
The glass substrate with a fine structure according to any one of claims 1 to 4.
A conductive layer that covers at least a part of the flat surface and at least a part of the inner surface of the hole.
Glass substrate with conductive layer.
A method of manufacturing a glass substrate with a microstructure.
Irradiating a glass substrate with a pulse laser to form an altered part,
It comprises removing the altered portion by wet etching to form holes in the glass substrate.
The glass substrate with a microstructure is
A flat surface formed on the first main surface of the glass substrate with a microstructure,
The hole opened in the first main surface and
It has an annular protrusion formed along the opening of the hole in the first main surface.
The distance D between the flat surface and the end of the protruding portion in the thickness direction of the glass substrate with a microstructure is 0.001 μm ≦ D ≦ 2 μm.
A method that satisfies at least one of the following conditions (i) and (ii).
(I) 0.003 μm ≤ {(Rav) 2 + (Raf) 2 } 0.5 ≤ 0.1 μm
(Ii) 2 ≦ Rav / Raf ≦ 50
Rav is the arithmetic mean roughness based on Japanese Industrial Standards (JIS) B 0601: 1994 on the surface of the protrusion.
Raf is the arithmetic mean roughness based on the Japanese Industrial Standards (JIS) B 0601: 1994 for the flat surface.
The method according to claim 6, wherein the wet etching is performed using an alkaline etching solution or an acidic etching solution.
The method according to claim 7, wherein the alkaline etching solution is a potassium hydroxide aqueous solution, a sodium hydroxide aqueous solution, or a mixture of a potassium hydroxide aqueous solution and a sodium hydroxide aqueous solution.