Wiring boards and devices

Abstract

To provide a wiring board that can suppress peeling of the black layer. [Solution] A wiring board is provided, comprising: a glass substrate 1 having a first surface and a second surface opposite to the first surface; a plurality of wirings 2 arranged on the first surface side of the glass substrate; a cover insulating layer 3 arranged on the first surface side of the glass substrate and having openings at positions corresponding to the wirings; a black layer 4 arranged on the side of the cover insulating layer opposite to the glass substrate and having openings at positions corresponding to the wirings; and a transparent insulating portion 5 arranged on the side of the cover insulating layer opposite to the glass substrate and covering at least the side of the black layer.

Description

Technical Field

[0001] The present disclosure relates to a wiring board and a device.

Background Art

[0002] As insulating substrates constituting a wiring board, for example, glass epoxy substrates, resin substrates containing epoxy resin or acrylic resin, etc., and glass substrates are known. Among them, since glass substrates are excellent in optical properties such as flatness, dimensional stability, heat resistance, insulation, and transparency, the development of wiring boards using glass substrates has been promoted.

[0003] In recent years, a member including an insulating substrate having a plurality of through-holes and through electrodes provided inside the through-holes, so-called through electrode substrate, has been used in various applications. As the insulating substrate constituting the through electrode substrate, a glass substrate may be used for the above reasons. Such a glass substrate having through-holes is called a TGV (Through-Glass Via).

[0004] By the way, in the field of devices having optical semiconductor elements such as light-emitting elements or light-receiving elements, a black layer may be arranged around the optical semiconductor element. For example, Patent Document 1 discloses covering the side surface of a light-emitting element with a light-shielding member in a light-emitting device in which a light-emitting element is mounted on a printed board. Further, Patent Document 2 discloses a solder resist resin composition used for an optical device, which contains a resin and a black pigment and satisfies a predetermined transmittance.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] In a wiring board, for example, a black layer is placed on top of an insulating layer. However, if the adhesion between the insulating layer and the black layer is poor, the black layer may peel off during the manufacturing process of the wiring board or the device.

[0007] This disclosure is an invention made in view of the above circumstances, and its main objective is to provide a wiring substrate capable of suppressing the peeling of the black layer. [Means for solving the problem]

[0008] One embodiment of the present disclosure provides a wiring board comprising: a glass substrate having a first surface and a second surface opposite to the first surface; a plurality of wirings disposed on the first surface side of the glass substrate; a cover insulating layer disposed on the first surface side of the glass substrate and having openings at positions corresponding to the wirings; a black layer disposed on the side of the cover insulating layer opposite to the glass substrate and having openings at positions corresponding to the wirings; and a transparent insulating portion disposed on the side of the cover insulating layer opposite to the glass substrate and covering at least the side of the black layer.

[0009] Another embodiment of the present disclosure provides a device having the above-described wiring board and a light-emitting element or light-receiving element electrically connected to the wiring of the wiring board. [Effects of the Invention]

[0010] This disclosure provides the effect of suppressing the peeling of the black layer. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view illustrating a wiring board in this disclosure. [Figure 2] This is a schematic cross-sectional view illustrating a wiring board in this disclosure. [Figure 3] This is a schematic cross-sectional view illustrating a wiring board in this disclosure. [Figure 4] This is a schematic cross-sectional view illustrating an example of a device in this disclosure. [Figure 5] This is a schematic cross-sectional view illustrating the occurrence of peeling of the black layer on a wiring board. [Modes for carrying out the invention]

[0012] Embodiments of this disclosure will be described below with reference to drawings and other figures. However, this disclosure can be implemented in many different ways and should not be interpreted as being limited to the embodiments described below. In addition, the drawings may be schematically represented in terms of width, thickness, shape, etc. of each part compared to the actual form in order to make the explanation clearer, but these are merely examples and should not limit the interpretation of this disclosure. Furthermore, in this specification and each figure, elements similar to those described above with respect to previously shown figures will be denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0013] In this specification, when describing a configuration in which one member is placed on top of another member, unless otherwise specified, the terms "on top" or "below" include both cases: one in which the other member is placed directly above or below the other member so as to be in contact with it, and another in which the other member is placed above or below the other member via yet another member. Similarly, when describing a configuration in this specification in which one member is placed on the surface of another member, unless otherwise specified, the terms "on the surface" or "on the surface" include both cases: one in which the other member is placed directly above or below the other member so as to be in contact with it, and another in which the other member is placed above or below the other member via yet another member.

[0014] The wiring boards and devices described herein will be explained in detail below.

[0015] A. Wiring board The wiring board in this disclosure comprises a glass substrate having a first surface and a second surface facing the first surface; a plurality of wirings arranged on the first surface side of the glass substrate; a cover insulating layer arranged on the first surface side of the glass substrate and having openings at positions corresponding to the wirings; a black layer arranged on the side of the cover insulating layer opposite to the glass substrate and having openings at positions corresponding to the wirings; and a transparent insulating portion arranged on the side of the cover insulating layer opposite to the glass substrate and covering at least the side of the black layer.

[0016] Figure 1 is a schematic cross-sectional view illustrating a wiring board in this disclosure. As shown in Figure 1, the wiring board 10 includes a glass substrate 1 having a first surface 1a and a second surface 1b facing the first surface 1a, a plurality of wirings 2 arranged on the first surface 1a side of the glass substrate 1, a cover insulating layer 3 arranged on the first surface 1a side of the glass substrate 1 and having openings 3a at positions corresponding to the wirings 2, a black layer 4 arranged on the side of the cover insulating layer 3 opposite to the glass substrate 1 and having openings 4a at positions corresponding to the wirings 2, and a transparent insulating portion 5 arranged on the side of the cover insulating layer 3 opposite to the glass substrate 1 and covering the side surface 4b of the black layer 4.

[0017] FIG. 5(a) and FIG. 5(b) are schematic cross-sectional views for explaining the occurrence of peeling of the black layer in the wiring board. The wiring board 50 shown in FIG. 5(a) includes a glass substrate 51 having a first surface 51a and a second surface 51b facing the first surface 51a, a wiring 52 disposed on the first surface 51a side of the glass substrate 51, a cover insulating layer 53 disposed on the first surface 51a side of the glass substrate 51 and having an opening 53a at a position corresponding to the wiring 52, and a black layer 54 disposed on a surface of the cover insulating layer 53 opposite to the glass substrate 51 and having an opening 54a at a position corresponding to the wiring 52. In the wiring board, as shown in FIG. 5(b), in order to suppress corrosion such as oxidation of the wiring 52, a barrier metal layer 56 may be formed on the wiring 52 by plating. At this time, the plating solution may penetrate into the interface between the black layer 54 and the cover insulating layer 53, and peeling may occur at the end of the black layer 54. Further, when manufacturing a device using the wiring board, although not shown, when, for example, a light-emitting layer is formed on the wiring 52 by photolithography, peeling may occur in the black layer 54 due to the influence of the developer.

[0018] The inventors of the present application have found that the peeling of the black layer described above is caused by low adhesion between the black layer and the cover insulating layer. And it has been found that peeling of the black layer can be suppressed by covering at least the side surface of the black layer with a transparent insulating portion.

[0019] According to the present disclosure, as shown in FIG. 1, since at least the side surface 4b of the black layer 4 is covered by the transparent insulating portion 5, the interface between the cover insulating layer 3 and the black layer 4 is covered by the transparent insulating portion 5. Therefore, peeling of the black layer 4 due to low adhesion between the cover insulating layer 3 and the black layer 4 can be suppressed.

[0020] As shown in FIG. 2, it is preferable that the transparent insulating portion 5 covers not only the side surface 4b but also the upper surface 4c of the black layer 4. As described above, in a wiring board, when a barrier metal layer is formed on a wiring by plating, the black layer may be exposed to the plating solution and the color tone of the black layer may change. Also, when manufacturing a device using a wiring board, for example, when a light-emitting layer is formed on a wiring by photolithography, the black layer may be exposed to the developer and the color tone of the black layer may change. On the other hand, since the upper surface 4c of the black layer 4 is covered with the transparent insulating portion 5, it is possible to suppress a change in the color tone of the black layer during the manufacturing process of the wiring board or during the manufacturing process of the device.

[0021] As described above, the glass substrate has excellent optical properties. Therefore, in the glass substrate, light propagates isotropically in both the thickness direction and the plane direction. Thus, in a device in which a light-emitting element or a light-receiving element is disposed on a wiring board having a glass substrate, it is considered that light leakage, color mixing, stray light, etc. are likely to occur due to the propagation of light in the plane direction. Therefore, it is desirable that a black layer is disposed between adjacent light-emitting elements or between adjacent light-receiving elements. In the present disclosure, since a glass substrate is used, it is meaningful that the black layer is disposed and peeling of the black layer can be suppressed, and further, a change in the color tone of the black layer can be suppressed.

[0022] As shown in FIG. 2, the wiring board 10 in the present disclosure may further include a barrier metal layer 6 that protects the wiring 2.

[0023] In the wiring board of this disclosure, as shown in Figure 3, the glass substrate 1 preferably has through holes 1c that penetrate in the thickness direction, and the wiring board 10 preferably has through electrodes 7 disposed within the through holes 1c of the glass substrate 1. Furthermore, as shown in Figure 3, the wiring board 10 of this disclosure may have a first wiring laminate 8 between the glass substrate 1 and the cover insulating layer 3. The first wiring laminate 8 has one or more interlayer insulating layers 11 and conductive layers 12 disposed between each interlayer insulating layer 11, and each conductive layer 12 is electrically connected by vias 13. The conductive layers 12 in the first wiring laminate 8 are electrically connected to the wiring 2 and the through electrodes 7. Furthermore, as shown in Figure 3, the wiring board 10 of this disclosure may have a second wiring laminate 9 on the second surface 1b side of the glass substrate 1. The second wiring laminate 9 has one or more interlayer insulating layers 11 and conductive layers 12 disposed between each interlayer insulating layer 11, and each conductive layer 12 is electrically connected by vias 13. The conductive layer 12 in the second wiring laminate 9 is electrically connected to the wiring 2 and the through electrode 7.

[0024] The wiring boards described in this disclosure will be explained below for each component.

[0025] 1. Black layer In this disclosure, the black layer is located on the side of the cover insulating layer opposite to the glass substrate and has openings at positions corresponding to the wiring.

[0026] The black layer has light-shielding properties. Therefore, when a device is formed by arranging light-emitting elements on the wiring substrate according to this disclosure, it is possible to suppress light leakage to adjacent light-emitting elements, thereby suppressing color mixing and stray light. In addition, since the area where the black layer is arranged becomes a non-emitting area, contrast can be improved. Furthermore, when a device is formed by arranging light-receiving elements on the wiring substrate according to this disclosure, it is possible to suppress unwanted light incidence to the light-receiving elements and suppress stray light.

[0027] It is preferable that the black layer and the cover insulating layer are in direct contact. As described later, the black layer contains a coloring agent, and therefore its composition differs from that of the cover insulating layer, which is thought to result in low adhesion between the black layer and the cover insulating layer. For this reason, it is presumed that during the manufacturing process of the wiring board or the manufacturing process of a device using the wiring board, plating solutions, developing solutions, etc., may penetrate the interface between the black layer and the cover insulating layer, making the black layer prone to peeling. According to this disclosure, by covering at least the sides of the black layer with a transparent insulating portion, the interface between the black layer and the cover insulating layer can be covered, thereby suppressing peeling of the black layer.

[0028] The black layer is black in order to achieve the desired light-shielding properties. Preferably, the black layer contains a coloring agent that produces black. Here, "black" refers not only to colorless black, but also to colors such as bluish-black, greenish-black, reddish-black, brownish-black, orange-black, or whitish-black. Black pigments can be used as the coloring agent. Examples of black pigments include inorganic oxides such as black titanium oxide, and carbon compounds such as carbon black, graphite, fullerene, and carbon fiber. One or more black pigments can be used in combination. In addition, other colored pigments may be mixed with the black pigment.

[0029] The content of black pigment in the black layer may be, for example, 2% by mass or more and 10% by mass or less, 3% by mass or more and 9% by mass or less, or 4% by mass or more and 8% by mass or less.

[0030] Furthermore, the main component of the black layer can be a resin capable of dispersing the aforementioned black pigment. The resin can be one commonly used in resist materials, including photocurable resins and thermosetting resins. Examples of photocurable resins include acrylic resins, epoxy resins, polyimide resins, polyvinyl cinnamate resins, and cyclocompound rubbers. One or more photocurable resins can be used in combination. Examples of thermosetting resins include epoxy resins, acrylic resins, melamine resins, maleimide resins, polyurethane resins, diallyl phthalate resins, and silicone resins. One or more thermosetting resins can be used in combination.

[0031] The black layer may, if necessary, contain various known additives such as polymerization initiators, curing agents, photosensitizers, dispersants, surfactants, stabilizers, and leveling agents.

[0032] The method for forming the black layer is not particularly limited as long as it can form a black layer of the desired shape, and examples include photolithography and screen printing.

[0033] The thickness of the black layer is not particularly limited, as long as it is a thickness that provides the desired light-shielding properties. Specifically, the thickness of the black layer is preferably 1.5 μm or more, and more preferably 3.0 μm or more. When the thickness of the black layer is within the above range, the desired light-shielding properties are easily obtained. On the other hand, the thickness of the black layer may be, for example, 10.0 μm or less, and also 5.0 μm or less. When the thickness of the black layer is within the above range, transparent insulating portions can be easily formed on the sides and top surface of the black layer. In addition, the wiring board and device can be made thinner. That is, the thickness of the black layer may be 1.5 μm or more and 10.0 μm or less, and also 3.0 μm or more and 5.0 μm or less.

[0034] In this specification, the thickness of each layer is measured based on cross-sectional images of the wiring board taken using a scanning electron microscope (SEM). The thickness is the arithmetic mean of the thicknesses at any five locations.

[0035] The width W2 of the black layer is, for example, 30 μm or more, and may be 50 μm or more. On the other hand, the width W2 of the black layer is, for example, 200 μm or less, and may be 100 μm or less. That is, the width W2 of the black layer is, for example, 30 μm or more and 200 μm or less, and may be 50 μm or more and 100 μm or less. Note that the width W2 of the black layer is the width of the black layer in the planar direction of the wiring board, as shown in Figures 1 and 2.

[0036] In this specification, the width of each layer in the planar direction is measured based on cross-sectional images of the wiring board taken using a scanning electron microscope (SEM). The width is the arithmetic mean of the widths at any five points.

[0037] The black layer has openings at positions corresponding to the wiring. Therefore, when a device is formed by arranging multiple light-emitting elements or multiple photodetectors on a wiring board, the black layer is positioned between adjacent light-emitting elements or adjacent photodetectors. The planar shape of the openings is not particularly limited and examples include circles and rectangles. It is preferable that the size of the openings in the black layer is larger than the size of the openings in the cover insulating layer described later. Furthermore, since the black layer has openings at positions corresponding to the wiring, it may have patterns such as a grid pattern, a circular pattern, or a diamond-shaped (rhombus) pattern.

[0038] The arrangement of the black layer is not particularly limited as long as the black layer has openings at positions corresponding to the wiring, but it is preferable that the black layer 4 is arranged such that, in a cross-section including the opening 4a of the black layer 4, the end of the black layer 4 and the end of the wiring 2 do not overlap, as illustrated in Figures 1 and 2.

[0039] 2. Transparent insulating part In this disclosure, the transparent insulating portion is positioned on the side of the cover insulating layer opposite to the glass substrate and is positioned to cover at least the side of the black layer. By covering the side of the black layer with the transparent insulating portion, peeling of the black layer during the manufacturing process of the wiring board or the device can be suppressed. In particular, it is preferable that the transparent insulating portion is positioned to cover the side and top surface of the black layer. By also covering the top surface of the black layer with the transparent insulating portion, changes in the color of the black layer during the manufacturing process of the wiring board or the device can be suppressed. The top surface of the black layer refers to the side of the black layer opposite to the cover insulating layer.

[0040] The transparent insulating portion is transparent. In this specification, "transparent" means that it transmits visible light, and when the wiring board is observed from the transparent insulating portion side, the black layer can be seen. Specifically, the total light transmittance of the measurement sample having a glass substrate and a transparent insulating portion is preferably 85% or higher, and more preferably 90% or higher. The total light transmittance is measured in accordance with JIS K 7361-1:1997. In the measurement sample, the glass substrate is the glass substrate that constitutes the wiring board. The transparent insulating portion is made of the same material as the transparent insulating portion that constitutes the wiring board, and is formed to have the same thickness T1 as the transparent insulating portion that constitutes the wiring board.

[0041] The material for the transparent insulating part is not particularly limited as long as it is an insulating and transparent material, and insulating materials generally used for the insulating layer of wiring boards can be used, and both organic and inorganic materials can be used. Preferably, the material for the transparent insulating part is a transparent insulating resin. Examples of transparent insulating resins include polyimide, polyamide, polyamide-imide, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyetheretherketone, polyethersulfone, polycarbonate, polyetherimide, epoxy resin, phenolic resin, polyphenylene ether, acrylic resin, polyolefin, polycycloolefin, and liquid crystalline polymer compounds. Examples of polyolefins include polyethylene and polypropylene. Examples of polycycloolefins include polynorbornene.

[0042] The width W1 of the transparent insulating portion located on the side of the black layer is preferably, for example, 10.0 μm or more, and more preferably 20.0 μm or more. By having the width W1 of the transparent insulating portion within the above range, peeling of the black layer can be further suppressed. On the other hand, the width W1 of the transparent insulating portion is preferably, for example, 50.0 μm or less, and more preferably 30.0 μm or less. Generally, when viewed by a person, an area wider than 50 μm is visible. By having the width W1 of the transparent insulating portion within the above range, it is possible to suppress the visibility of each layer, such as wiring, located below the black layer, because the black layer is not present. That is, the width W1 of the transparent insulating portion located on the side of the black layer is preferably, for example, 10.0 μm or more, 50.0 μm or less, and more preferably 20.0 μm or more, 30.0 μm or less. Note that the width W1 of the transparent insulating portion located on the side of the black layer is the distance from the edge of the black layer to the edge of the transparent insulating portion in the planar direction of the wiring board, as shown in Figures 1 and 2.

[0043] The thickness T1 of the transparent insulating portion may be the same as the thickness of the black layer, or it may be thicker than the thickness of the black layer. As shown in Figure 1, the thickness T1 of the transparent insulating portion is the maximum distance from the side of the transparent insulating portion 5 facing the cover insulating layer 3 to the side of the transparent insulating portion 5 facing the cover insulating layer 3. The thickness T1 of the transparent insulating portion is preferably 3.0 μm or more, and more preferably 8.0 μm or more. When the thickness T1 of the transparent insulating portion is within the above range, it is easier to cover the sides and top surface of the black layer with the transparent insulating portion. On the other hand, the thickness T1 of the transparent insulating portion is preferably 30.0 μm or less, preferably 20.0 μm or less, and more preferably 10.0 μm or less. When the thickness T1 of the transparent insulating portion is within the above range, the wiring board and device can be made thinner. Specifically, the thickness T1 of the transparent insulating portion is, for example, 3.0 μm or more and 30.0 μm or less, preferably 3.0 μm or more and 20.0 μm or less, and more preferably 5.0 μm or more and 10.0 μm or less.

[0044] The thickness T2 of the transparent insulating portion located on the upper surface of the black layer is preferably 3.0 μm or more, and more preferably 5.0 μm or more. By having the thickness T2 of the transparent insulating portion within the above range, changes in the color of the black layer during the manufacturing process of the wiring board or the device can be further suppressed. On the other hand, the thickness T2 of the transparent insulating portion may be, for example, 20.0 μm or less, and also 10.0 μm or less. By having the thickness T2 of the transparent insulating portion within the above range, the wiring board and the device can be made thinner, and there is no risk of the black color exhibited by the black layer being impaired by the transparent insulating portion. Specifically, the thickness T2 of the transparent insulating portion located on the upper surface of the black layer is preferably 3.0 μm or more and 20.0 μm or less, and more preferably 5.0 μm or more and 10.0 μm or less.

[0045] The thickness of the transparent insulating layer located on the side of the black layer may be greater than, the same as, or less than the thickness T2 of the transparent insulating layer located on the top surface of the black layer.

[0046] The transparent insulating portion has openings at positions corresponding to the wiring. The planar shape of the openings is not particularly limited and may be a circle or a rectangle. The size of the openings in the transparent insulating portion may be larger or smaller than the size of the openings in the cover insulating layer described later, but it is preferable that they be about the same size as the openings in the cover insulating layer.

[0047] For forming the transparent insulating layer, general methods for forming insulating layers can be used, and these can be appropriately selected depending on the material of the insulating layer. Examples include photolithography and screen printing.

[0048] 3. Cover insulation layer The cover insulating layer in this disclosure is positioned on the first surface side of the glass substrate and has openings at positions corresponding to the wiring. The cover insulating layer may or may not be in direct contact with the glass substrate. The cover insulating layer may also be in direct contact with the first wiring laminate described later.

[0049] The material for the cover insulating layer is not particularly limited as long as it is an insulating material, and insulating materials generally used for the insulating layer of wiring boards can be used, and both organic and inorganic materials can be used. The material for the cover insulating layer is preferably an insulating resin. Examples of insulating resins include polyimide, polyamide, polyamide-imide, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyetheretherketone, polyethersulfone, polycarbonate, polyetherimide, epoxy resin, phenolic resin, polyphenylene ether, acrylic resin, polyolefin, polycycloolefin, and liquid crystalline polymer compounds.

[0050] To improve adhesion between the transparent insulating portion and the cover insulating layer, it is preferable that the transparent insulating portion and the cover insulating layer contain the same type of material, more preferably the same type of insulating resin, and even more preferably the same resin. In the context of resins, "same type" refers to materials that share a common skeleton with the main chain of the resin, such as polyimides, epoxy resins, or acrylic resins.

[0051] The cover insulation layer has openings at positions corresponding to the wiring. The plan view shape of the openings is not particularly limited and may be, for example, a circle or a rectangle. The size of the openings is appropriately selected depending on the application of the wiring board.

[0052] The thickness of the cover insulation layer is not particularly limited and may be the same as the thickness of the wiring, or it may be thicker or thinner than the thickness of the wiring. In particular, from the viewpoint of covering the wiring, it is preferable that the thickness of the cover insulation layer be the same as the thickness of the wiring or thicker than the thickness of the wiring. The difference between the thickness of the cover insulation layer T3 and the thickness of the wiring T4 (T3-T4) is, for example, 0.0 μm or more, and preferably 1.0 μm or more. On the other hand, the above difference (T3-T4) is, for example, 10.0 μm or less, and preferably 5.0 μm or less. The thickness of the cover insulation layer may be, for example, 3.0 μm or more, and may be 5.0 μm or more. On the other hand, the thickness of the cover insulation layer may be, for example, 20.0 μm or less, and may be 10.0 μm or less. The thickness of the cover insulation layer may be, for example, 3.0 μm or more and 20.0 μm or less, and 5.0 μm or more and 10.0 μm or less.

[0053] For forming the cover insulating layer, general insulating layer formation methods can be used and are appropriately selected depending on the insulating layer material, etc. Examples include photolithography and screen printing.

[0054] 4. Wiring The wiring substrate in this disclosure has a plurality of wirings arranged on the first surface side of a glass substrate. The wirings may or may not be in direct contact with the glass substrate. The wirings may also be in direct contact with a first wiring laminate described later. If the wiring substrate has through electrodes arranged in first through holes of the glass substrate, the wirings are electrically connected to the through electrodes. If the wiring substrate further has a first wiring laminate, the wirings are electrically connected to the through electrodes and the conductive layers in the first wiring laminate.

[0055] As wiring materials, for example, metals such as copper, molybdenum, titanium, tungsten, tantalum, aluminum, gold, silver, nickel, and palladium, or alloys containing at least one of these metals, can be used. By using copper or aluminum, which have high conductivity, the increase in resistance can be suppressed. Furthermore, by using copper, which has relatively low hardness, it is possible to provide a wiring board that can construct more reliable electrical connections.

[0056] The wiring may be single-layered or multi-layered, consisting of multiple layers stacked on top of each other.

[0057] The thickness of the wiring may be, for example, 0.1 μm or more, and may be 5 μm or more. On the other hand, the thickness of the wiring may be, for example, 20 μm or less, and may be 15 μm or less. The thickness of the wiring may be, for example, 0.1 μm or more and 20 μm or less, and 5 μm or more and 15 μm or less. This allows sufficient conductivity to be obtained.

[0058] For the wiring formation method, general wiring formation methods can be used, such as CVD, sputtering, and plating.

[0059] If the wiring board has multiple conductive layers in the thickness direction, the wiring is located furthest from the glass substrate on the first surface side of the glass substrate. The wiring may include pad portions.

[0060] 5. Glass substrate The wiring board in this disclosure has a glass substrate. As shown in Figure 1, the glass substrate 1 has a first surface 1a and a second surface 1b facing the first surface 1a.

[0061] Because glass substrates have good flatness, fine wiring can be formed at a narrow pitch. Furthermore, since the thermal expansion coefficient of the glass substrate can be adjusted by its composition, a glass substrate with a desirable thermal expansion coefficient can be selected.

[0062] Examples of glass used in glass substrates include alkali-free glass and quartz.

[0063] As shown in Figure 3, it is preferable that the glass substrate 1 has a through hole 1c that penetrates in the thickness direction. The plan view shape of the through hole in the glass substrate is, for example, approximately circular. Furthermore, the cross-sectional shape of the through hole in the glass substrate is not particularly limited and includes a straight shape, an inverse tapered shape in which the opening diameter on the first surface side is larger than the opening diameter on the second surface side, a forward tapered shape in which the opening diameter on the first surface side is smaller than the opening diameter on the second surface side, an hourglass shape that includes a portion where the diameter is smallest at a predetermined position between the first and second surfaces, and a bowing shape in which the diameter is largest at a predetermined position between the first and second surfaces.

[0064] Methods for forming through holes include, for example, laser irradiation, etching such as plasma etching or wet etching, mechanical processing methods such as sandblasting or ultrasonic drilling, and photolithography.

[0065] The thickness of the glass substrate is, for example, 100 μm or more, but may also be 200 μm or more, 300 μm or more, or 400 μm or more. By having the glass substrate thickness within the above range, it is possible to suppress excessive deflection of the glass substrate. This prevents difficulties in handling the glass substrate during the manufacturing process, and prevents the glass substrate from warping due to internal stresses such as thin films placed on the first or second surface of the glass substrate. On the other hand, the thickness of the glass substrate is, for example, 2000 μm or less, but may also be 1000 μm or less, or 800 μm or less. If the thickness of the glass substrate is within the above range, the time required for the process of forming through holes in the glass substrate can be shortened. Specifically, the thickness of the glass substrate is 100 μm or more and 2000 μm or less, but may also be 200 μm or more and 1000 μm or less, 300 μm or more and 1000 μm or less, or 400 μm or more and 800 μm or less.

[0066] 6. Barrier metal layer As shown in Figure 2, the wiring board 10 in this disclosure may further have a barrier metal layer 6 on the side of the wiring 2 opposite to the glass substrate 1. The presence of the barrier metal layer suppresses corrosion such as oxidation of the wiring and protects the wiring. It is preferable that the barrier metal layer and the wiring are in direct contact.

[0067] The barrier metal layer can be made of any material that is corrosion-resistant and electrically conductive, such as gold, nickel, or solder.

[0068] The thickness of the barrier metal layer is not particularly limited and can be selected appropriately depending on the material and formation method of the barrier metal layer, as long as it is thick enough to suppress corrosion such as oxidation of the wiring. Specifically, the thickness of the barrier metal layer may be, for example, 1.0 μm or more and 20.0 μm or less, or 4.0 μm or more and 15.0 μm or less.

[0069] The method for forming the barrier metal layer is appropriately selected depending on the material of the barrier metal layer. Among these, plating is preferred, and electroless plating is more preferred. In other words, the barrier metal layer is preferably a plated layer. When the wiring board is immersed in a plating solution, if the interface between the black layer and the cover insulating layer is exposed, the plating solution penetrates easily, and the black layer tends to peel off. Therefore, when the barrier metal layer is formed by a plating process, the effect of the transparent insulating portion in this disclosure is fully realized.

[0070] 7. Other (1)Through electrode As shown in Figure 3, if the glass substrate 1 has a through hole 1c, it is preferable that the wiring substrate 10 has a through electrode 7 placed within the through hole 1c of the glass substrate 1.

[0071] The through-electrode only needs to be able to electrically connect the first and second surfaces of the glass substrate, and its form is not particularly limited. The form of the through-electrode may be, for example, a through-electrode that fills a through-hole in the glass substrate, a so-called filled via, or a through-electrode that is placed only on the side wall of the through-hole in the glass substrate, a so-called conformal via. Furthermore, if the through-electrode is a conformal via, a hollow portion may be placed inside the through-hole, or the inside of the through-hole may be filled with a resin portion.

[0072] The material of the through electrode is not particularly limited as long as it is conductive, and conductive materials commonly used for through electrodes can be used, and can be appropriately selected depending on the shape and formation method of the through electrode. Examples of materials for the through electrode include metals such as copper, gold, silver, platinum, rhodium, tin, aluminum, nickel, and chromium, or alloys containing these metals.

[0073] The through-electrode may be a single layer or a multilayer structure with multiple layers stacked on top of each other. For example, the through-electrode may have a seed layer positioned on the side wall of the through-hole in the glass substrate and a plating layer positioned on the side of the seed layer opposite to the side wall of the through-hole. The material for the seed layer can be appropriately selected from materials used for seed layers in general plating methods. The material for the seed layer is preferably a conductive material that adheres well to the glass substrate, and examples include titanium, molybdenum, tungsten, tantalum, nickel, chromium, aluminum, compounds thereof, and alloys thereof. If the plating layer contains copper, the material for the seed layer is preferably a material that can suppress the diffusion of copper into the interior of the glass substrate, and examples include titanium nitride, molybdenum nitride, and tantalum nitride. The material for the plating layer is preferably a conductive material that adheres well to the seed layer, and examples include the materials for the through-electrode described above.

[0074] Furthermore, in the through-electrode, it is preferable that an adhesion layer is placed on the side wall of the through-hole in the glass substrate. The adhesion layer ensures good adhesion between the glass substrate and the through-electrode. The adhesion layer has high adhesion to the glass substrate. The adhesion layer may also serve to suppress the diffusion of metal elements in the through-electrode into the interior of the glass substrate through the side wall of the through-hole. When the through-electrode has an adhesion layer, the through-electrode may have, in order from the side wall side of the through-hole in the glass substrate, an adhesion layer, a seed layer, and a plating layer.

[0075] When the conductive material constituting the through electrode is copper, examples of materials for the adhesion layer include titanium, titanium oxide, titanium nitride, molybdenum, molybdenum nitride, tantalum, and tantalum nitride. The adhesion layer may be a single layer or a multilayer. In particular, it is preferable that the adhesion layer contains titanium oxide as its main component.

[0076] Furthermore, when the through-electrode is a conformal via and the through-hole is filled with a resin portion, examples of materials for the resin portion include epoxy resin, acrylic resin, polyimide, polyamide, polyester, and the like.

[0077] For forming through electrodes, general methods for forming through electrodes can be used and are appropriately selected depending on the shape of the through electrode. Examples of through electrode formation methods include PVD methods such as vacuum deposition and sputtering, CVD methods, and plating methods.

[0078] (2) First wiring laminate As shown in Figure 3, the wiring substrate 10 in this disclosure may or may not have a wiring laminate 8 between the glass substrate 1 and the cover insulating layer 3, which includes one or more interlayer insulating layers. Hereinafter, the wiring laminate disposed between the glass substrate and the cover insulating layer may be referred to as the first wiring laminate. The first wiring laminate has one or more interlayer insulating layers and conductive layers disposed between each interlayer insulating layer, and each conductive layer is electrically connected by vias. Hereinafter, the interlayer insulating layers constituting the first wiring laminate may be referred to as the first interlayer insulating layer, the conductive layers disposed between each first interlayer insulating layer may be referred to as the first conductive layer, and the vias electrically connecting each first conductive layer may be referred to as the first via.

[0079] The number of layers in the first interlayer insulating layer is one or more, may be two or more, three or more, or four or more. On the other hand, the number of layers in the first interlayer insulating layer is preferably 10 or less, more preferably 8 or more, and even more preferably 7 or less.

[0080] The thickness of the first interlayer insulating layer is, for example, 1.5 μm or more, and may be 2.5 μm or more. On the other hand, the thickness of the first interlayer insulating layer is, for example, 6 μm or less. The thickness of the first interlayer insulating layer is, for example, 1.5 μm or more and 6 μm or less, and may be 2.5 μm or more and 6 μm or less.

[0081] Examples of methods for forming the first interlayer insulating layer include photolithography and screen printing.

[0082] The first wiring laminate has a first conductive layer disposed between each first interlayer insulating layer and electrically connected to a through electrode. The first conductive layer may be one layer or two or more layers. When the wiring substrate has two or more first conductive layers on the first surface side of the glass substrate, each first conductive layer is laminated in the thickness direction via the first interlayer insulating layer. Furthermore, each first conductive layer is electrically connected via a first via.

[0083] The material for the first conductive layer is not particularly limited as long as it is conductive, and conductive materials commonly used for wiring on wiring boards can be used. Examples of conductive materials include metallic materials such as metals and metal oxides, conductive resins containing conductive fillers and resins, and conductive polymers.

[0084] The thickness of the first conductive layer is, for example, 0.1 μm or more, and may be 5 μm or more. On the other hand, the thickness of the first conductive layer is, for example, 20 μm or less, and may be 15 μm or less. The thickness of the first conductive layer is, for example, 0.1 μm or more and 20 μm or less, and may be 5 μm or more and 15 μm or less. For example, when the conductive layer is formed by a sputtering method, a relatively thin conductive layer can be obtained. Also, for example, when the conductive layer is formed by a plating method, a relatively thick conductive layer can be obtained.

[0085] The method for forming the first conductive layer may be an additive method or a subtractive method.

[0086] The first via is electrically connected to the through electrode and wiring. The material of the first via is not particularly limited as long as it is conductive, and a conductive material commonly used for vias can be used, and can be appropriately selected depending on the via's shape and formation method. A general via formation method can be used for the first via, and can be appropriately selected depending on the via's shape and other factors.

[0087] (3) Second wiring laminate As shown in Figure 3, the wiring substrate 10 in this disclosure may or may not have a wiring laminate 9 including one or more interlayer insulating layers on the second surface 1b side of the glass substrate 1. Hereinafter, the wiring laminate arranged on the second surface side of the glass substrate may be referred to as the second wiring laminate.

[0088] The second wiring laminate comprises one or more interlayer insulating layers and conductive layers arranged between each interlayer insulating layer, with each conductive layer electrically connected by vias. The interlayer insulating layers included in the second wiring laminate are sometimes referred to as second interlayer insulating layers, the conductive layers arranged between each second interlayer insulating layer are sometimes referred to as second conductive layers, and the vias that electrically connect each second conductive layer are sometimes referred to as second vias.

[0089] The second interlayer insulating layer, the second conductive layer, and the second via are the same as those described above for the first conductive layer, the first via, and the first interlayer insulating layer.

[0090] The number of layers in the second interlayer insulating layer may be the same as the number of layers in the first interlayer insulating layer. This is because it can suppress warping of the glass substrate when using a large glass substrate.

[0091] The second conductive layer located on the side of the second interlayer insulating layer that is furthest from the glass substrate and is opposite to the glass substrate may include a pad portion.

[0092] B. Devices The device in this disclosure comprises the above-described wiring board and a light-emitting element or a light-receiving element electrically connected to the wiring of the wiring board.

[0093] Figure 4 is a schematic cross-sectional view showing an example of a device in this disclosure. As shown in Figure 4, the device 100 includes the wiring board 10 described above and an optical semiconductor element 20 electrically connected to the wiring 2 of the wiring board 10. The optical semiconductor element 20 is a light-emitting element or a light-receiving element.

[0094] The devices described in this disclosure are explained below for each configuration.

[0095] 1. Wiring board Since the wiring board is described in detail in "A. Wiring Board" above, the explanation will be omitted here.

[0096] 2. Light-emitting element or light-receiving element Examples of light-emitting elements include LED elements and organic EL elements. LED stands for light-emitting diode. The LED elements may be small in size, such as those that make up so-called mini-LEDs or micro-LEDs.

[0097] Examples of light-receiving elements include phototransistors, photodiodes, and photoresistors. A photoresistor is also called a photocell.

[0098] In the case of light-emitting elements, the light-emitting elements may be arranged by directly forming a light-emitting layer on the wiring of the circuit board, or the light-emitting elements may be prepared in advance and mounted on the wiring of the circuit board. In the case of light-receiving elements, the light-receiving elements may be prepared in advance and mounted on the wiring of the circuit board. When mounting light-emitting elements or light-receiving elements on the wiring of a circuit board, the light-emitting elements or light-receiving elements can be mounted on the wiring of the circuit board via a joint. As the joint, a joint commonly used for mounting elements can be used. Examples of materials for the joint include solder, gold or gold alloy, conductive paste, anisotropic conductive paste, and anisotropic conductive film.

[0099] 3.Applications The applications of the devices in this disclosure are not particularly limited. In the case of light-emitting elements, an example of a device application is a display device. In the case of light-receiving elements, an example of a device application is an optical sensor.

[0100] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure.

[0101] This disclosure provides the following inventions. [1] A glass substrate having a first surface and a second surface facing the first surface, Multiple wirings arranged on the first surface side of the glass substrate, A cover insulating layer is provided on the first surface side of the glass substrate and has openings at positions corresponding to the wiring. A black layer is provided on the side of the cover insulating layer opposite to the glass substrate, and has openings at positions corresponding to the wiring. A transparent insulating portion is provided on the side of the cover insulating layer opposite to the glass substrate, and covers at least the side of the black layer. A wiring board having the following features. [2] The wiring board according to [1], wherein the transparent insulating portion covers the side and top surfaces of the black layer. [3] The wiring board according to [1] or [2], having a barrier metal layer on the side of the above wiring opposite to the above glass substrate. [4] The wiring board described in [3], wherein the barrier metal layer is a plating layer. [5] A wiring substrate according to any one of [1] to [4], having a wiring laminate that includes one or more interlayer insulating layers between the glass substrate and the cover insulating layer. [6] A wiring board according to any one of [1] to [5], wherein the glass substrate has a plurality of through holes, and through electrodes are arranged within the through holes. [7] A wiring board as described in any of [1] to [6], A device having a light-receiving element or light-emitting element electrically connected to the wiring of the above-mentioned wiring board. [Explanation of Symbols]

[0102] 1 ... Glass substrate 1a… First surface of the glass substrate 1b… Second surface of the glass substrate 1c... Through hole 2… Wiring 3. Cover insulation layer 4… Black layer 5… Transparent insulating part 6… Barrier metal layer 7 … Through electrode 8 ... First wiring laminate 9 … Second wiring stack

Claims

1. A glass substrate having a first surface and a second surface opposite to the first surface, A plurality of wirings arranged on the first surface side of the glass substrate, A cover insulating layer is disposed on the first surface side of the glass substrate and has an opening at a position corresponding to the wiring, A black layer is provided on the side of the cover insulating layer opposite to the glass substrate, and has an opening at a position corresponding to the wiring. A wiring board having a transparent insulating portion disposed on the side of the cover insulating layer opposite to the glass substrate and covering at least the side of the black layer.

2. The wiring board according to claim 1, wherein the transparent insulating portion covers the side and top surfaces of the black layer.

3. The wiring substrate according to claim 1, wherein the wiring has a barrier metal layer on the side of the wiring opposite to the glass substrate.

4. The wiring board according to claim 3, wherein the barrier metal layer is a plating layer.

5. The wiring substrate according to claim 1, further comprising a wiring laminate including one or more interlayer insulating layers between the glass substrate and the cover insulating layer.

6. The wiring board according to claim 1, wherein the glass substrate has a plurality of through holes, and through electrodes are arranged in the through holes.

7. A wiring board according to any one of claims 1 to 6, A device having a light-receiving element or light-emitting element electrically connected to the wiring of the wiring board.

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