Wired glass substrate and manufacturing method for wired glass substrate

Abstract

To provide a wired glass substrate having good conductivity, in which the production of the wired glass substrate by perforation made by etching is simplified to simplify a process of imparting conductivity and the wired glass substrates are easily layered.SOLUTION: A wired glass substrate which includes a through-hole portion in a thickness direction of a glass substrate and is electrically connected, comprises: a first recessed hole portion formed in a first surface part of the glass substrate; a second recessed hole portion formed in a second surface part opposite to the first surface part of the glass substrate and communicating with the first recessed hole portion to form the through-hole portion; a protective metal film which is deposited on the first recessed hole portion and protects a first metal film portion from an etching process on the glass substrate; a first metal film portion which is deposited along the first recessed hole portion; and a second metal film portion which is deposited along the second recessed hole portion and is in contact with and electrically connected to the first metal film portion.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a wired glass substrate and a method for manufacturing the wired glass substrate, and more particularly to a wired glass substrate in which electrical conductivity is imparted to pores in a glass plate, such as a glass interposer, and a method for manufacturing the same. [Background technology]

[0002] Semiconductor elements such as various memories, CPUs, and GPUs mounted on a circuit board have terminals for electrical connection. The pitch of the connection terminals and the pitch of the connection parts of the circuit board that are electrically connected to the semiconductor elements usually differ by several to several tens of times. Therefore, a relay board for connection called an interposer is used to electrically connect the semiconductor elements and the circuit board. The semiconductor elements are mounted on one side of the interposer, and the circuit board is connected to the other side.

[0003] Organic resin materials have been used as materials for interposers. However, in order to improve the processing power of semiconductor elements and respond to high integration, there is a demand for fine wiring formation in interposers. However, with interposers that use conventional organic resin materials, the resin absorbs moisture and expands and contracts greatly depending on the temperature, making it difficult to handle fine wiring.

[0004] Therefore, currently, to address the issues with organic resin materials, interposers using silicon and glass as base materials are being developed. These inorganic materials are less susceptible to moisture absorption, and their thermal expansion coefficients are similar to those of semiconductor elements, reducing the effects of expansion and contraction due to temperature.

[0005] However, interposers using silicon as a base material require surface protection, and the materials, processing costs, etc. are expensive. For this reason, glass interposers are currently in vogue (see Patent Documents 1 and 2, etc.).

[0006] Laser irradiation is often used to drill holes in glass substrates such as glass interposers. However, drilling holes by etching the glass substrate may be relatively advantageous due to the processing time required to form multiple through holes in the glass substrate by laser irradiation. In addition, there is an increasing demand for thinner glass substrates. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-113392 A [Patent Document 2] JP 2018-170372 A Summary of the Invention [Problem to be solved by the invention]

[0008] The inventors have conducted extensive research into perforation by etching of glass substrates, and as a result have developed a wired glass substrate which simplifies the processing for making the through holes conductive after perforation and which allows easy lamination of other wired glass substrates.

[0009] The present invention has been made in consideration of the above-mentioned points, and provides a wired glass substrate having good electrical conductivity, which simplifies the production of a wired glass substrate by perforating through etching, thereby facilitating processing for making the substrate electrically conductive, and which allows wired glass substrates to be easily laminated together, and a method for producing the same. [Means for solving the problem]

[0010] That is, the wired glass substrate of the embodiment is a wired glass substrate having a through hole portion in the thickness direction of the glass substrate and is electrically connected, and is characterized by having a first recess portion formed in a first surface portion of the glass substrate, a second recess portion formed in a second surface portion that is the opposite surface of the first surface portion of the glass substrate and communicating with the first recess portion to form a through hole portion, a protective metal film that is applied to the first recess portion and protects the first metal film portion from an etching process performed on the glass substrate, a first metal film portion that is applied along the first recess portion, and a second metal film portion that is applied along the second recess portion and is in contact with and electrically connected to the first metal film portion.

[0011] Furthermore, in the wired glass substrate, the protective metal film may be deposited along the first recess portion, and the second metal film portion may be deposited along the second recess portion and in contact with the first metal film portion to be electrically connected.

[0012] Furthermore, in the wiring glass substrate, the protective metal film may be removed.

[0013] Furthermore, in the wired glass substrate, the second metal film portion of one wired glass substrate may be connected to the first metal film portion of another wired glass substrate.

[0014] Furthermore, in the wired glass substrate, the second metal film portion of one wired glass substrate may be connected to the first metal film portion of another wired glass substrate via a conductive material.

[0015] Furthermore, in the wired glass substrate, the conductive material may contain a metal member.

[0016] Furthermore, in the wired glass substrate, the protective metal film may be made of chromium, and the first metal film portion and the second metal film portion may be made of copper.

[0017] Furthermore, in the wired glass substrate, the glass substrate may have a thickness of 10 to 50 μm.

[0018] Furthermore, in the wired glass substrate, a reinforcing agent may be provided in the recess of the first metal film portion that is applied along the first recess portion and in the recess of the second metal film portion that is applied along the second recess portion.

[0019] Furthermore, the manufacturing method of the wired glass substrate of the embodiment is characterized by comprising a first concave hole forming step of forming a first concave hole on a first surface of the glass substrate by etching; a protective metal film applying step of applying a protective metal film to the first concave hole to protect the first metal film from the etching process of the glass substrate; a first metal film applying step of applying the first metal film along the first concave hole; a second concave hole forming step of forming a second concave hole on a second surface of the first substrate opposite the first concave hole; and a second metal film applying step of applying the second metal film along the second concave hole to connect it to the first metal film.

[0020] Furthermore, the method for manufacturing the wiring glass substrate may include a removal step of removing the protective metal film.

[0021] Furthermore, the manufacturing method for a wired glass substrate may include a lamination process for connecting and laminating a second metal film portion of one wired glass substrate to a first metal film portion of another wired glass substrate via a conductive material. Effect of the Invention

[0022] According to the wired glass substrate of the present invention, there is provided a wired glass substrate having a through hole in the thickness direction of the glass substrate and for electrical connection, the substrate comprising a first recessed hole formed in a first surface portion of the glass substrate, a second recessed hole formed in a second surface portion opposite the first surface portion of the glass substrate and communicating with the first recessed hole to form a through hole, a protective metal film adhered to the first recessed hole and protecting the first metal film portion from etching of the glass substrate, a first metal film portion adhered along the first recessed hole portion, and a second metal film portion adhered along the second recessed hole portion and in contact with the first metal film portion for electrical connection. This simplifies the production of the wired glass substrate by perforating holes through etching, and facilitates processing for electrical conductivity.

[0023] Furthermore, the method for manufacturing a wired glass substrate of the present invention includes a first concave portion forming step of forming a first concave portion on a first surface portion of the glass substrate by etching, a protective metal film applying step of applying a protective metal film to the first concave portion to protect the first metal film portion from the etching process of the glass substrate, a first metal film applying step of applying the first metal film portion along the first concave portion, a second concave portion forming step of forming a second concave portion on a second surface portion of the first surface portion of the glass substrate opposite the first concave portion, and a second metal film applying step of applying the second metal film portion along the second concave portion to connect it to the first metal film portion. This simplifies the production of a wired glass substrate by perforating holes by etching, facilitates processing for making the substrate conductive, and makes it easy to stack wired glass substrates together. [Brief description of the drawings]

[0024] [Figure 1] 1A is a first schematic cross-sectional view, FIG. 1B is a second schematic cross-sectional view, and FIG. 1C is a third schematic cross-sectional view showing a manufacturing process of a wiring glass substrate. [Diagram 2] 3A is a fourth schematic cross-sectional view, FIG. 3B is a fifth schematic cross-sectional view, and FIG. 3C is a sixth schematic cross-sectional view showing a process for producing a wiring glass substrate. [Diagram 3] 1A is a seventh schematic cross-sectional view, FIG. 1B is an eighth schematic cross-sectional view, and FIG. 1C is a ninth schematic cross-sectional view showing a manufacturing process for a wiring glass substrate. [Figure 4] FIG. 1A is a schematic cross-sectional view of a wired glass substrate according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of a wired glass substrate according to a second embodiment. [Diagram 5] FIG. 2A is a first schematic cross-sectional view during etching treatment, FIG. 2B is a second schematic cross-sectional view during etching treatment, and FIG. 2C is a third schematic cross-sectional view during etching treatment. [Figure 6] FIG. 2 is a schematic cross-sectional view of a wiring glass substrate during lamination. [Figure 7] FIG. 11 is a schematic cross-sectional view of another example of lamination of wiring glass substrates. [Figure 8] FIG. 2 is a schematic cross-sectional view of a state in which a wiring glass substrate is mounted on a base substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The wiring glass substrate of the embodiment is a glass substrate having a through hole portion penetrating the front and back surfaces of the glass substrate, and a conductive metal material is disposed in the through hole portion, and is mainly used as an interposer. The glass interposer referred to here is a member that serves as a relay substrate for electrically wiring and connecting various semiconductor elements such as memories, CPUs, and GPUs mounted on a circuit board to the circuit board. In particular, since the glass interposer itself is formed only of glass and a conductive material for wiring, it does not include materials with different thermal expansion coefficients such as resins, and deformation due to heat exposure during use is reduced. Of course, the wiring glass substrate of the embodiment can be applied to various uses other than interposers.

[0026] The wiring glass substrate 1 of the embodiment will be described with reference to the drawings, starting with its manufacturing method. The schematic cross-sectional views of FIGS. 1 to 4 show the processing steps of drilling holes in a glass substrate and imparting electrical conductivity. In FIG. 1(A), a glass substrate 10 to be processed is prepared. For example, non-alkali glass, borosilicate glass, etc. are used for the glass substrate 10 in view of the ease of reliability of the substrate having a semiconductor. Due to the influence of corrosion caused by the subsequent etching process, the final thickness of the glass substrate 10 is 10 to 50 μm, preferably 10 to 30 μm, and more preferably 10 to 20 μm. At the start of processing in FIG. 1(A), the thickness is set to about 50 μm, taking into account the influence of etching. For convenience, in the drawings, the lower side of the glass substrate 10 is designated as the first surface 11, and the opposite side is designated as the second surface 12.

[0027] As shown in FIG. 1(B), a surface protective film 21 is provided on the first surface 11 of the glass substrate 10 to etch the area where the first recess 13 is to be formed (to form the first recess 13). Chromium is used for the surface protective film 21 because of its resistance to etching with hydrofluoric acid, and the area where the first recess 13 is to be formed is opened as an opening 24 in the surface protective film 21. A known pattern formation method is used to form the opening 24 on the first surface 11. For example, processes such as resist coating, heating (pre-baking), exposure, development, and heating (post-baking) are performed. Similar processes are also performed to form the opening 24 on the second surface 12.

[0028] As shown in FIG. 1(C), the first surface 11 of the glass substrate 10 is exposed at the opening 24 of the surface protective film 21, so that the hydrofluoric acid entering through the opening 24 starts to form a recess on the first surface 11 of the glass substrate 10, and the recess gradually becomes larger. In this way, the first recess 13 having a sufficient area according to the thickness of the glass substrate 10 is formed on the first surface 11 of the glass substrate 10 ("first recess forming step"). The surface protective film 21 may be formed on the second surface 12 of the glass substrate 10, or the surface protective film 21 may be omitted so that the second surface 12 is exposed. In the embodiment, hydrofluoric acid is used to etch the glass substrate 10. Instead of hydrofluoric acid, a strong base solution such as caustic soda may be used for etching. In this case, the material of the surface protective film 21 and the protective metal film 23 can be appropriately changed to a base-resistant material.

[0029] As shown in each diagram of FIG. 1, a first recess 13 of a predetermined size is formed on a first surface 11, which is one surface of a glass substrate 10. Then, as shown in FIG. 2(A), a surface protective film 21 formed on the first surface 11 and the second surface 12 is removed. As shown in FIG. 2(B), a protective metal film 23 is first formed on the inner circumferential surface 16 of the first recess 13 and in the vicinity of the opening of the first recess 13 ("protective metal film deposition process"). A first metal film portion 26 is deposited on the entire first recess 13 and on the first surface 11 around the first recess 13 so as to cover the protective metal film 23 ("first metal film portion deposition process").

[0030] The protective metal film 23 is intended to reduce the corrosive effect of etching on the first metal film portion 26 around the first recessed hole portion 13 when forming the second recessed hole portion 14 described later. The first recessed hole portion 13 is formed to a specified size through the process of FIG. 1. Therefore, the shape of the completed first recessed hole portion 13 is maintained, and further, when the second recessed hole portion 14 is formed, the protective metal film 23 is applied to prevent the etching from proceeding excessively toward the first recessed hole portion 13 side and the shape of the recess from becoming too large. When forming the protective metal film 23 and the first metal film portion 26 on the first surface portion 11 of the glass substrate 10, a known pattern formation method is adopted. For example, processes such as resist coating, heating (pre-baking), exposure, development, and heating (post-baking) are performed. Then, as shown in the figure, a pattern (a groove-shaped cut in the figure) is formed in the protective metal film 23 and the first metal film portion 26.

[0031] In FIG. 2(C), the glass substrate 10 of FIG. 2(B) is placed on a supporting substrate. In the illustrated embodiment, a base substrate 50, which will be described later, is used as the supporting substrate. In the base substrate 50, reference numeral 51 denotes a hole in the base substrate 50, and reference numeral 52 denotes a base electrode. Then, a conductive material 31 is filled so as to close the first recessed portion 13 (see the description of FIG. 6 for details). In addition to the illustrated base substrate 50, any suitable member capable of holding the glass substrate 10, such as a supporting dummy substrate, may be used as the supporting substrate. The glass substrate 10 is thinned by etching, which will be described later, to a thickness of about 10 μm. In this case, it is difficult to transport and process the thinned glass substrate 10 alone, so that the glass substrate 10 is placed on a supporting substrate in the initial stage of processing in order to improve the ease of handling of the glass substrate 10, to improve resistance to bending deformation, and to facilitate transportation.

[0032] In Fig. 3(A), the glass substrate 10 is thinned by etching (also called slimming, which is a process for reducing the thickness of the glass substrate through an etching process) on the second surface 12 side of the glass substrate 10 in Fig. 2(B) described above, and processed to the final thickness of the glass substrate 10. The final thickness of the glass substrate 10 is preferably 10 to 20 µm. When thinning (slimming) by etching, in order to avoid the influence of etching on the base substrate 50, a corrosion protection film is attached to the base substrate 50 or a resin coating material is applied thereto.

[0033] After the thinning (slimming) by etching, as shown in FIG. 3(B), a surface protective film 21 is provided on the second surface 12 of the glass substrate 10 in order to etch the area where the second recessed hole 14 is to be formed (to form the second recessed hole 14). The area where the second recessed hole 14 is to be formed is opened as an opening 24 in the surface protective film 21. Since the second surface 12 of the glass substrate 10 is exposed at the opening 24 in the surface protective film 21, a recess begins to be formed on the second surface 12 of the glass substrate 10 by the hydrofluoric acid penetrating from the opening 24, and the recess gradually becomes larger. In this way, the second recessed hole 14 of a sufficient size according to the thickness of the glass substrate 10 is also formed on the second surface 12 of the glass substrate 10 ("second recessed hole forming process").

[0034] Then, second recessed hole 14 finally reaches first recessed hole 13, and through hole 15 is formed connecting first surface 11 to second surface 12 of glass substrate 10. Protective metal film 23 adheres to first recessed hole 13, and therefore acts as an obstacle to etching penetrating from second surface 12, making it extremely difficult for etching to proceed toward first recessed hole 13. Therefore, the shape of first recessed hole 13 is maintained, and etching of second surface 12 is completed.

[0035] In FIG. 3(C), the surface protective film 21 provided for protection from etching is removed. As for the protective metal film 23, the bottom portion of the second recessed hole portion 14 is removed, and the first metal film portion 26 on the first recessed hole portion 13 side is exposed in the through hole portion 15. Then, the second metal film portion 27 is applied along the recessed shape of the second recessed hole portion 14 ("second metal film portion application step"). The protective metal film 23 formed on the first surface portion 11 of the glass substrate 10 except for the first recessed hole portion 13 is in close contact with the base substrate 50 serving as a supporting substrate directly below. For this reason, it is difficult for a chemical solution to penetrate into the gap of the contact, and it is difficult to remove the protective metal film 23, and the protective metal film 23 is left behind.

[0036] 1 to 3, a through hole portion 15 is formed in the thickness direction of the glass substrate 10, and the first metal film portion 26 and the second metal film portion 27 are joined at the through hole portion 15 of the glass substrate 10. For convenience, the illustration shows only one through hole portion 15. In an actual glass substrate 10, the through hole portions 15 are formed in multiple locations.

[0037] Fig. 4(A) shows a form in which the removal of the surface protective film 21 and the protective metal film 23 is omitted. In this form, the protective metal film 23 is covered with a first metal film portion 26, and the surface protective film 21 is covered with a second metal film portion 27. In the form of Fig. 4(A), the processing and associated treatments are simplified by omitting the removal of the surface protective film 21 and the protective metal film 23. In the figure, the configuration of the base substrate 50 is omitted for convenience of explanation.

[0038] 4(B) corresponds to the above-mentioned FIG. 3(C), and prior to deposition of the second metal film portion 27, the surface protective film 21 and the protective metal film 23 of the through-hole portion 15 are removed ("removal step"). After the removal, the first metal film portion 26 is exposed and the second metal film portion 27 is deposited thereon. The first metal film portion 26 and the second metal film portion 27 are made of the same metal type, such as copper, while the surface protective film 21 and the protective metal film 23 are made of chromium, which is a different metal type from the first metal film portion 26 and the second metal film portion 27. Therefore, by removing the different metals, the first metal film portion 26 and the second metal film portion 27 are directly bonded to each other, resulting in good conductivity.

[0039] The wired glass substrate 1 is completed through the steps detailed in FIG. 1 to FIG. 3. The structure of the wired glass substrate 1 can be summarized as follows: the wired glass substrate 1 is provided with a through hole 15 in the thickness direction of the glass substrate 10, and is electrically connected. A first recessed hole 13 is formed in a first surface 11 of the glass substrate 10. A second recessed hole that communicates with the first recessed hole 13 and forms a through hole 15 is formed in a second surface 12, which is the opposite surface of the glass substrate 10 to the first surface 11. A protective metal film 23 is provided that is applied to the first recessed hole 13 and protects a first metal film 26 from an etching process for the glass substrate 10. A first metal film 26 is provided that is applied along the first recessed hole 13. A second metal film 27 is provided that is applied along the second recessed hole 14 and is in contact with the first metal film 26 for electrical connection.

[0040] In the structure of FIG. 4(A), the first metal film portion 26 covers the protective metal film 23 and is attached along the first recessed hole portion 13. Then, the second metal film portion 27 is attached along the second recessed hole portion 14, and the first metal film portion 26 comes into contact with the second metal film portion 27 via the protective metal film 23 to be electrically connected. In the structure of FIG. 4(B), the protective metal film 23 of the through hole portion 15 is removed, and the top side of the first recessed hole portion 13 in the through hole portion 15 of the first metal film portion 26 already attached along the first recessed hole portion 13 is exposed. Then, in a state in which the surface protective film 21 is removed and only the glass substrate 10 remains on the second surface portion 12, the second metal film portion 27 is attached along the second recessed hole portion 14 and comes into contact with the first metal film portion 26 to be electrically connected to each other.

[0041] Both the first metal film portion 26 and the second metal film portion 27 are conductors such as copper foil, gold foil, etc., and as can be seen from Fig. 4, the first metal film portion 26 and the second metal film portion 27 are joined to each other at the center of the through-hole portion 15. Thus, both surfaces of the glass substrate 10 are electrically connected (conductivity is ensured) through the through-hole portion 15, and the wired glass substrate 1 is produced.

[0042] The schematic cross-sectional view of FIG. 5 shows the formation of the first recessed hole portion 13 and the second recessed hole portion 14 by etching. In particular, FIG. 5 shows an enlarged view of only the vicinity of the first recessed hole portion 13. In FIG. 5(A), a surface protective film 21 of chromium, which is resistant to an etching solution such as hydrofluoric acid, is formed (attached) on the first surface portion 11 of the glass substrate 10, and at the same time, an opening 24 is formed in the surface protective film 21 to expose the first surface portion 11. According to the example of FIG. 5, the opening diameter of the opening 24 is about 10 μm. The exposed surface of the glass substrate 10 at the opening 24 is exposed to the etching solution, and the glass is gradually eroded, resulting in a concave hole portion. Note that the material of the surface protective film 21, etc. is changed when an etching treatment solution other than hydrofluoric acid is used.

[0043] 5(B) shows a state in which the etching of the opening 24 has progressed further. As can be seen from the drawing, the surface protective film 21 remains as it was originally, and the vitreous material of the glass substrate 10 is eroded and dissolved by the etching liquid that has infiltrated from the opening 24. In other words, the etching liquid also flows around to the back surface of the surface protective film 21 and erodes the vitreous material.

[0044] 5(C), the etching proceeds further to form a first recess 13 of a desired size. The amount of erosion of the glass correlates with the exposure time to the etching solution. The size and depth of the recess formed by erosion can be adjusted by controlling the time the glass substrate 10 is sprayed or immersed in the etching solution.

[0045] According to the example of FIG. 5, the first recessed hole portion 13 formed through etching is formed approximately in the shape of a trapezoidal cone. In the figure, the distance between the starting points 13a, 13a of the first surface portion 11 of the first recessed hole portion 13, i.e., the opening diameter of the first recessed hole portion 13 is larger than the opening diameter of the opening 24. The distance between the starting points 13b, 13b of the top (bottom) of the first recessed hole portion 13, i.e., the diameter of the top (bottom) of the first recessed hole portion 13, is smaller than the opening diameter of the first recessed hole portion 13. The depth of the first recessed hole portion 13 from the first surface portion 11 is approximately the same as or larger than the opening diameter of the opening 24. When the first recessed hole portion 13 is regarded as a trapezoidal cone, a hypotenuse with an inclination angle θ is formed at the starting point position 13a. Similarly, a hypotenuse with an inclination angle φ is formed at the starting point position 13b. The inclination angles θ and φ are angles given for the sake of convenience and schematic illustration, and deformation, curvature, etc. may occur in the starting point position and the oblique side during actual etching.

[0046] 5 shows the formation of first recessed hole portion 13 in glass substrate 10. When second recessed hole portion 14 is formed, second recessed hole portion 14 has a trapezoidal cone shape similar to first recessed hole portion 13, and the inclination angle of the hypotenuse is in the same angle range as first recessed hole portion 13. However, the opening diameter of second surface portion 12 and the depth from second surface portion 12 are adjusted over the time of etching treatment of glass substrate 10, and the final size of second recessed hole portion 14 is adjusted.

[0047] As can be seen from the series of drawings, both the first recessed hole portion 13 and the second recessed hole portion 14 are formed in the shape of a trapezoidal cone, and are mortar-shaped with an inclination angle that starts from the surface of the glass substrate 10 and drops in a concave shape. Due to such an inclination angle, the first metal film portion 26 and the second metal film portion 27 can be relatively easily applied to the surfaces of the first recessed hole portion 13 and the second recessed hole portion 14. Since the first metal film portion 26 and the second metal film portion 27 are made of metal such as copper foil, the first metal film portion 26 and the second metal film portion 27 can be attached conformingly to each inclined surface of the first surface portion 11 and the second surface portion 12, which are the surfaces of the glass substrate 10, and the first recessed hole portion 13 and the second recessed hole portion 14, due to the malleability of the metal.

[0048] In this way, the first recessed hole portion 13 and the second recessed hole portion 14 formed in the glass substrate 10 penetrate each other, and as a result, a through hole portion 15 is formed in the thickness direction of the glass substrate 10. Then, as explained in the above-mentioned FIG. 4, the first metal film portion 26 and the second metal film portion 27 are joined to each other at the center of the through hole portion 15, and both surfaces of the glass substrate 10 are electrically connected through the through hole portion 15.

[0049] In the illustrated embodiment, the first recessed hole portion 13 and the second recessed hole portion 14 have a shape similar to a trapezoidal cone, and therefore can be processed by coating with a metal film such as copper foil. In other words, by placing metal foil at the corresponding locations of the first recessed hole portion 13 and the second recessed hole portion 14, the metal foil can be easily coated on the surface (recessed hole portion) of the glass substrate 10 by the action of static electricity or the like. Since copper foil or the like can be used, the conductivity in the through hole portion 15 is good, and it is easy to suppress an increase in electrical resistance and heat generation (resistance heating) in the wired glass substrate 1. Of course, the first metal film portion 26 and the second metal film portion 27 may be made of a conductive material other than metal foil.

[0050] In contrast, the shape of the through-hole formed in the glass substrate exemplified in Patent Documents 1 and 2 presented in the background art is a shape that is close to a cylinder. For this reason, in the previous patent documents, the shape of the through-hole made it difficult to apply a conductive material such as metal foil. Therefore, the inside of the through-hole was made conductive by a method such as plating, thereby electrically connecting (making conductive) both surfaces of the glass substrate. Obviously, the processing and the like becomes more complicated in the case of plating, compared with the manufacturing method using metal foil for the first metal film portion 26 and the second metal film portion 27 of the embodiment.

[0051] Therefore, the wired glass substrate and the method for manufacturing the wired glass substrate of the embodiment can be manufactured more simply and inexpensively than the conventional manufacturing method due to the shapes of the first and second recesses formed in the glass substrate by etching. Also, the metal foil is thicker than in the conventional plating manufacturing method, which is advantageous in that the electrical resistance is less likely to increase.

[0052] The wired glass substrate of the embodiment can be used alone (single layer). However, typically, a plurality of wired glass substrates are laminated and integrated. Fig. 6 is a schematic cross-sectional view of a plurality of wired glass substrates 1 laminated together. As shown in the figure, the second metal film portion 27 of one wired glass substrate 1 is connected to the first metal film portion 26 of another wired glass substrate 1. This configuration is repeated to laminate the wired glass substrates 1.

[0053] When the wired glass substrates 1 are laminated together, a conductive material 31 is interposed between the wired glass substrates 1. In the drawing, the conductive material 31 is injected into the periphery between the second metal film portion 27 of one wired glass substrate 1 and the first metal film portion 26 of the other wired glass substrate 1, and is filled so as to fill the first recessed hole portion 13 and the second recessed hole portion 14.

[0054] In principle, it is possible to directly bond the second metal film portion 27 of one wired glass substrate 1 to the first metal film portion 26 of another wired glass substrate 1 without using the conductive material 31. However, if the first metal film portion 26 and the second metal film portion 27 are in direct contact with each other, the first metal film portion 26 and the second metal film portion 27 are affected by deformation and bending due to thermal expansion of the glass substrate 10. Then, depending on the amount of deformation of the glass substrate 10, a gap may be generated between the first metal film portion 26 and the second metal film portion 27, resulting in loss of conductivity, or excessive pressure may be generated between the glass substrates 10, resulting in cracks around the through-hole portion 15. Therefore, the conductive material 31 is used as a buffer material to accommodate deformation of the glass substrate 10.

[0055] The conductive material 31 is preferably a conductive resin paste containing fine particles of metal such as copper, silver, gold, platinum, nickel, lead, etc. The conductive resin paste is based on acrylic resin, urethane resin, or various organic solvents, and fine metal particles are dispersed in the base material at a ratio of 60 to 90% by weight. The conductive resin paste contains a conductive resin ink.

[0056] The conductive material 31 has a relatively good conductivity. However, the conductive material 31 may have an uneven conductivity due to the influence of the metal particles contained in the resin component being unevenly distributed due to the specific gravity, etc. Therefore, in order to ensure stable conductivity, the conductive material 31 contains a metal member 32. The metal member 32 in FIG. 6 is a metal ball interposed in the conductive material 31 between the second metal film portion 27 of one wiring glass substrate 1 and the first metal film portion 26 of the other wiring glass substrate 1 and contacts both metal films. Therefore, the second metal film portion 27 and the first metal film portion 26 can be directly electrically connected through the metal member 32 (the metal ball shown in the figure). Note that the metal member 32 may be a member such as a washer (not shown) instead of the metal ball shown in the figure. In addition, in order to make the conductive material 31 and the metal member 32 uniform in conductivity, the metal member 32 made of the same material as the metal particles contained in the conductive material 31 is used.

[0057] In the wired glass substrate 1 of the embodiment, metal foil (copper foil) is used for the first metal film portion 26 and the second metal film portion 27. The first metal film portion 26 and the second metal film portion 27 are pressed by the conductive material 31 filled in the first recessed hole portion 13 and the second recessed hole portion 14, and are pushed toward the inner side of the recessed hole portion (the center side of the through hole portion 15). However, due to the influence of the fluidity of the conductive material 31 filled in the first recessed hole portion 13 and the second recessed hole portion 14, there is a risk of misalignment and deformation occurring at the joint portion 28 between the first metal film portion 26 and the second metal film portion 27.

[0058] As shown in the schematic cross-sectional view of FIG. 7, a reinforcing agent 33 is used to address such a problem. Prior to injecting the conductive material 31 into the first metal film portion 26 of the first recessed hole portion 13 and the second metal film portion 27 of the second recessed hole portion 14, the reinforcing agent 33 is injected into the recess of the first metal film portion 26 and the recess of the second metal film portion 27. The injected reinforcing agent 33 hardens in each recess. Then, the hardened reinforcing agents 33 maintain the shape of the joint portion 28 between the first metal film portion 26 and the second metal film portion 27, and the mutual joint is maintained. Thereafter, while leaving the reinforcing agent 33 remaining, the conductive material 31 is injected into the periphery between the second metal film portion 27 of one wiring glass substrate 1 and the first metal film portion 26 of the other wiring glass substrate 1, and is filled so as to fill the first recessed hole portion 13 and the second recessed hole portion 14. The reinforcing agent 33 is a thermosetting resin agent such as an acrylic resin or a urethane resin. The reinforcing agent 33 may have a composition that is conductive, similar to the conductive material 31 described above.

[0059] The schematic cross-sectional view of FIG. 8 shows a state where a plurality of wired glass substrates 1, which are shown and described in the series, are stacked and mounted on the upper part of a glass base substrate 50. FIG. 8 is a diagram using the wired glass substrate 1 of FIG. 7 described above, and is a disclosed example of a so-called glass interposer 1G. A circuit board (not shown) is provided below the base substrate 50, and semiconductor elements such as a CPU and a GPU are mounted above the plurality of stacked wired glass substrates 1. A base electrode 52 is provided at the upper end of a hole 51 of the base substrate 50, and an electrode probe (not shown) is inserted therein. The electrode probe is connected to the base electrode 52, and the base electrode 52 is in contact with the conductive material 31, so that it can be electrically connected to the conductive material 31 of the wired glass substrate 1. As shown in the diagram, the first metal film portion 26 and the second metal film portion 27 provided in the through-hole portion 15 of each wired glass substrate 1 are mutually connected to ensure conductivity from the base substrate 50 side to the uppermost wired glass substrate 1. [Explanation of symbols]

[0060] 1. Wiring glass substrate 1G Glass Interposer 10 Glass substrate 11 First side 12 Second side part 13 First concave hole part 14 Second recessed hole part 15 Through hole 16 Inner surface 21 Surface protective film 23 Protective metal film 24 Opening 26 First metal film part 27 Second metal film part 31 Conductive Materials 32 Metallic parts 33 Reinforcement 50 Base Board

Claims

1. A wiring glass substrate having a through hole portion in a thickness direction of the glass substrate and electrically connected, A first recess portion formed on a first surface portion of the glass substrate; a second recess portion formed in a second surface portion of the glass substrate opposite to the first surface portion and communicating with the first recess portion to form the through hole portion; a protective metal film that is attached to the first recessed hole and protects the first metal film portion from an etching process for the glass substrate; a first metal film portion disposed along the first recess portion; a second metal film portion that is attached along the second recessed hole portion and that is in contact with and electrically connected to the first metal film portion.

1. A wiring glass substrate comprising:

2. the protective metal film is applied along the first recess portion, 2 . The wired glass substrate according to claim 1 , wherein the second metal film portion is deposited along the second recessed hole portion and is in contact with and electrically connected to the first metal film portion.

3. 2. The wired glass substrate according to claim 1, wherein the protective metal film has been removed.

4. The wired glass substrate according to claim 1 , wherein the second metal film portion of one of the wired glass substrates is connected to the first metal film portion of another of the wired glass substrates.

5. 2 . The wired glass substrate according to claim 1 , wherein the first metal film portion of one of the wired glass substrates is connected to the second metal film portion of the other of the wired glass substrates via a conductive material.

6. 6. The wired glass substrate according to claim 5, wherein the conductive material includes a metal member.

7. 2. The wired glass substrate according to claim 1, wherein the protective metal film is made of chromium, and the first metal film portion and the second metal film portion are made of copper.

8. 2. The wired glass substrate according to claim 1, wherein the glass substrate has a thickness of 10 to 50 μm.

9. 2 . The wired glass substrate according to claim 1 , wherein a reinforcing agent is provided in the recess of the first metal film portion coated along the first recess and in the recess of the second metal film portion coated along the second recess.

10. A method for producing the wiring glass substrate according to claim 1, comprising the steps of: a first recessed hole forming step of forming a first recessed hole in a first surface portion of the glass substrate by etching; a protective metal film coating step of coating the first recessed hole with a protective metal film for protecting the first metal film portion from an etching process for the glass substrate; a first metal film portion deposition step of depositing a first metal film portion along the first recessed hole portion; a second recess portion forming step of forming a second recess portion by etching a second surface portion of the glass substrate opposite the first recess portion of the first surface portion; and a second metal film portion deposition step of depositing a second metal film portion along the second recessed hole portion and connecting the second metal film portion to the first metal film portion.

2. A method for producing a wiring glass substrate comprising the steps of:

11. The method for producing a wiring glass substrate according to claim 10 , further comprising a removing step of removing the protective metal film.

12. 11. The method for manufacturing a wired glass substrate according to claim 10, further comprising a lamination step of connecting and laminating the second metal film portion of one of the wired glass substrates to the first metal film portion of another of the wired glass substrates via a conductive material.

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