Wiring board and method for manufacturing the same

Abstract

To improve quality of a wiring board, and facilitate the manufacture thereof.SOLUTION: A wiring board 100 includes a core layer 1 composed of glass, first and second insulation layers 21 and 22 which are provided on each of a first surface 1a side and a second surface 1b side of the core layer 1 and contain a resin, a first conductor layer 31 formed on the first insulation layer 21, a second conductor layer 32 formed on the second insulation layer 22, a through hole conductor 4 for connecting the first conductor layer 31 and the second conductor layer 32, a first coating layer 61 which is provided between the first surface 1a and the first insulation layer 21, a second coating layer 62 which is provided between the second surface 1b and the second insulation layer 22, a first through hole 11 penetrating through the core layer 1, the first coating layer 61 and the second coating layer 62, and a resin filling body 5 filling the first through hole 11, wherein the through hole conductor 4 is positioned on at least a side wall of a second through hole 52 penetrating through the first insulation layer 21, the second insulation layer 22 and the resin filling body 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wiring board and a method for manufacturing a wiring board. [Background technology]

[0002] Patent Document 1 discloses a wiring board having a core substrate including a glass plate, and a manufacturing method thereof. Resin layers and conductor layers are laminated in this order on both sides of the glass plate, and through-holes are formed that penetrate the resin layers on both sides and the glass plate, and through-hole conductors made of plating films are formed to fill the through-holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-127701 Summary of the Invention [Problem to be solved by the invention]

[0004] In the wiring board disclosed in Patent Document 1, a conductor layer made of a metal such as copper is formed on a glass plate with a resin layer interposed between them. Both are hard and have different thermal expansion coefficients, and only the resin layer is interposed between the glass and the metal, so stress can occur due to sudden temperature changes, etc. Furthermore, since the through-hole conductors are formed by drilling the through-holes directly in the glass plate, forming the through-hole conductors can be difficult. [Means for solving the problem]

[0005] The wiring board of the present invention includes a core layer made of glass and having a first surface and a second surface opposite the first surface, a first insulating layer provided on the first surface side of the core layer and containing a resin, a second insulating layer provided on the second surface side of the core layer and containing a resin, a first conductor layer formed on the first insulating layer, a second conductor layer formed on the second insulating layer, and through-hole conductors connecting the first conductor layer and the second conductor layer. The wiring board further includes a first covering layer provided between the first surface and the first insulating layer and covering the first surface, a second covering layer provided between the second surface and the second insulating layer and covering the second surface, a first through hole penetrating the core layer, the first covering layer, and the second covering layer, and a resin filler filling the first through hole, the through-hole conductor being located on at least a side wall of the second through hole penetrating the first insulating layer, the second insulating layer, and the resin filler.

[0006] A method for manufacturing a wiring board of the present invention includes preparing a glass plate having a first surface, a second surface opposite the first surface, and a side surface between the first surface and the second surface covered with a coating material; forming a first through hole that penetrates the glass plate, a first coating layer consisting of a portion of the coating material that covers the first surface, and a second coating layer consisting of a portion of the coating material that covers the second surface; forming a first insulating layer by supplying resin onto the first coating layer; forming a second insulating layer by supplying resin onto the second coating layer; forming a resin filler that fills the first through hole; forming a first conductor layer on the first insulating layer; forming a second conductor layer on the second insulating layer; and forming a through-hole conductor that penetrates the resin filler, the first insulating layer, and the second insulating layer to connect the first conductor layer and the second conductor layer.

[0007] According to the embodiment of the present invention, stress is less likely to occur between the glass plate and the conductor layer, which may suppress the occurrence of cracks, interfacial peeling, etc. Furthermore, it may be easier to form through-hole conductors that pass through the glass plate. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a wiring substrate according to an embodiment of the present invention. [Figure 2] Enlarged view of part II in Figure 1. [Figure 3A] FIG. 10 is a cross-sectional view showing another example of the wiring board according to the embodiment of the present invention. [Figure 3B] FIG. 10 is a cross-sectional view showing another example of the wiring board according to the embodiment of the present invention. [Figure 3C] FIG. 4 is a cross-sectional view showing another example of the through-hole conductor 4 in the wiring board according to one embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view showing an example of a wiring board according to another embodiment of the present invention. [Figure 5A] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5B] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5C] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5D] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5E] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5F] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5G] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5H] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 5I] 5A to 5C are cross-sectional views showing an example of a method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 6] 5A to 5C are cross-sectional views showing another example of the method for manufacturing a wiring board according to an embodiment of the present invention. [Figure 7A] 10A to 10C are cross-sectional views showing an example of a method for manufacturing a wiring board according to another embodiment of the present invention. [Figure 7B]10A to 10C are cross-sectional views showing an example of a method for manufacturing a wiring board according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] A wiring board and a method for manufacturing a wiring board according to an embodiment will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing a wiring board 100, which is an example of a wiring board according to an embodiment, and Fig. 2 is an enlarged view of part II in Fig. 1. Note that the wiring board 100 is merely an example of a wiring board according to this embodiment. The layered structure of the wiring board according to this embodiment and the number of conductor layers and insulating layers are not limited to the layered structure of the wiring board 100 shown in Fig. 1 and the number of conductor layers and insulating layers included in the wiring board 100.

[0010] 1, wiring board 100 includes insulating layer 1, first insulating layer 21, second insulating layer 22, first conductor layer 31, and second conductor layer 32. These conductor layers and insulating layers are stacked in the thickness direction of wiring board 100 (hereinafter, the thickness direction of wiring board 100 is also referred to as the "Z direction"). Insulating layer 1 occupies the center of the stacked structure of these conductor layers and insulating layers in the stacking direction (i.e., the Z direction). Therefore, insulating layer 1 is also referred to as "core layer 1."

[0011] The core layer 1 is made of glass. The core layer 1 has a first surface 1a that is approximately perpendicular to the Z direction and a second surface 1b that is the opposite surface to the first surface 1a. The first insulating layer 21 contains a resin 20 and is provided on the first surface 1a side of the core layer 1. The second insulating layer 22 contains a resin 20 and is provided on the second surface 1b side of the core layer 1. The first conductor layer 31 is formed on the first insulating layer 21. The second conductor layer 32 is formed on the second insulating layer 22.

[0012] In the description of the embodiments, the side of the wiring board 100 farther from the core layer 1 in the thickness direction is also referred to as the "outside," "upper side," or "above," or simply "top," and the side closer to the core layer 1 is also referred to as the "inside," "lower side," or "below," or simply "bottom." Furthermore, in each conductor layer, the conductor pattern contained in each conductor layer, and each insulating layer, the surface facing away from the core layer 1 is also referred to as the "upper surface," and the surface facing the core layer 1 side is also referred to as the "lower surface."

[0013] The wiring substrate 100 further includes a first covering layer 61, a second covering layer 62, a first through hole 11, and a resin filler 5 filling the first through hole 11. The first covering layer 61 covers the first surface 1a of the core layer 1. The first covering layer 61 is provided between the first surface 1a of the core layer 1 and the first insulating layer 21. The second covering layer 62 covers the second surface 1b of the core layer 1. The second covering layer 62 is provided between the second surface 1b of the core layer 1 and the second insulating layer 22. It is considered that the first surface 1a and the second surface 1b of the core layer 1, which are made of glass, are protected by the first covering layer 61 and the second covering layer 62, respectively. The first through hole 11 penetrates the core layer 1, the first covering layer 61, and the second covering layer 62. The first through hole 11 is filled with resin. The resin filling the first through hole forms a resin filler 5.

[0014] As shown in FIGS. 1 and 2, wiring board 100 further includes a through-hole conductor 4 connecting first conductor layer 31 and second conductor layer 32. Through-hole conductor 4 penetrates first insulating layer 21 and second insulating layer 22. Through-hole conductor 4 further penetrates resin filler 5. That is, through-hole conductor 4 penetrates first covering layer 61, core layer 1, and second covering layer 62 via resin filler 5. Resin that constitutes resin filler 5 is interposed between through-hole conductor 4 and core layer 1 made of glass.

[0015] 1 and 2, the side surfaces of through-hole conductor 4 are in contact with first insulating layer 21, second insulating layer 22, and resin filler 5 without contacting core layer 1. Specifically, second through holes 52 are formed penetrating first insulating layer 21, second insulating layer 22, and resin filler 5, and through-hole conductor 4 is located at least on the side walls of second through holes 52. In the example of FIGS. 1 and 2, through-hole conductor 4 is formed by a conductor filling second through hole 52, and through-hole conductor 4 fills second through hole 52.

[0016] The first conductor layer 31, the second conductor layer 32, and the through-hole conductors 4 are formed of any metal such as copper or nickel. Although Fig. 1 shows only conductor pads (through-hole pads) connected to the through-hole conductors 4 as the conductor patterns included in the first conductor layer 31 and the second conductor layer 32, each of the first conductor layer 31 and the second conductor layer 32 may include any conductor pattern.

[0017] Although the first and second conductor layers 31 and 32 are shown in FIG. 1 as being composed of a single layer for simplicity, they may specifically have a multilayer structure including two or more layers as shown in FIG. 2. In the example of FIG. 2, the first conductor layer 31 and the second conductor layer 32 are each composed of a metal foil 3a, a first metal film 3b, and a second metal film 3c. The metal foil 3a is disposed on the surface of the first insulating layer 21 or the surface of the second insulating layer 22. The first metal film 3b is formed on the metal foil 3a, and the second metal film 3c is formed on the first metal film 3b. Furthermore, the first metal film 3b and the second metal film 3c form a through-hole conductor 4. The first metal film 3b is, for example, an electroless plated film or a sputtered film, and the second metal film 3c is, for example, an electrolytic plated film.

[0018] The core layer 1 is mainly made of glass. Because the core layer 1 is made of glass, which generally has high rigidity, it is believed that warping of the wiring board 100 is unlikely to occur. In addition, because the core layer 1 is made of glass, the core layer 1 can be made thinner than when the core layer 1 is made of, for example, resin, and therefore the wiring board 100 can be made thinner. The thickness of the glass plate 1 is, for example, 5 μm or more and 1200 μm or less.

[0019] Examples of the glass constituting the core layer 1 include soda lime glass, alkali-free glass, quartz glass, borosilicate glass, etc. The core layer 1 may be a plate glass made of organic glass such as acrylic glass.

[0020] The first insulating layer 21 and the second insulating layer 22 are mainly formed of a resin 20. Examples of the resin 20 forming the first insulating layer 21 and the second insulating layer 22 include thermosetting resins such as epoxy resin, bismaleimide triazine resin (BT resin), and phenolic resin. The first insulating layer 21 and the second insulating layer 22 may be formed of a thermoplastic resin such as a fluororesin, a liquid crystal polymer (LCP), a fluoroethylene resin (PTFE), a polyester resin (PE), and a modified polyimide resin (MPI). These thermoplastic resins may have a lower dielectric constant and dielectric loss tangent than thermosetting resins, which may be advantageous for transmitting high-frequency signals through the first and second conductor layers 31 and 32.

[0021] The materials for the first coating layer 61 and the second coating layer 62 are not particularly limited as long as they can cover the surface of the core layer 1 made of glass and can laminate the first insulating layer 21 or the second insulating layer 22 thereon. For example, the first coating layer 61 and the second coating layer 62 may be formed mainly of a resin, similar to the first and second insulating layers 21 and 22. In the example shown in FIGS. 1 and 2, the first and second coating layers 61 and 62 contain a resin 60. Examples of the resin 60 forming the first coating layer 61 and the second coating layer 62 include an epoxy resin, a BT resin, and a phenolic resin. The first coating layer 61 and the second coating layer 62 may be formed of a fluororesin, an LCP, a PTFE, a PE, an MPI, or the like.

[0022] 1 and 2, the first insulating layer 21 and the second insulating layer 22 each further include a reinforcing material 2a, which is impregnated with resin 20. The first covering layer 61 and the second covering layer 62 each further include a reinforcing material 6a, which is impregnated with resin 60. Examples of the reinforcing material 2a and the reinforcing material 6a include glass fiber and aramid fiber, but the reinforcing material 2a and the reinforcing material 6a are not limited to these. Note that the first insulating layer 21 and the second insulating layer 22 do not necessarily include the reinforcing material 2a, and the first covering layer 61 and the second covering layer 62 do not necessarily include the reinforcing material 6a.

[0023] The first insulating layer 21, the second insulating layer 22, the first covering layer 61, and the second covering layer 62 may contain a filler (not shown) made of particles of, for example, silicon dioxide or alumina. The physical properties of the first insulating layer 21 and the second insulating layer 22, such as the coefficient of thermal expansion and the dielectric constant, may be adjusted by selecting the material of the reinforcing material 2a and / or adjusting the content of the filler (not shown). Similarly, the physical properties of the first covering layer 61 and the second covering layer 62, such as the coefficient of thermal expansion and the dielectric constant, may be adjusted by selecting the material of the reinforcing material 6a and / or adjusting the content of the filler (not shown).

[0024] In this embodiment, the first surface 1a of the core layer 1 made of glass is covered with a first covering layer 61, and the second surface 1b is covered with a second covering layer 62. The first covering layer 61 and the second covering layer 62 can protect the glass that makes up the core layer 1, particularly during the manufacturing process of the wiring board 100. For example, the occurrence of latent defects in the core layer 1, such as microcracks caused by external impact, can be prevented. Therefore, the occurrence of problems during use of the wiring board 100 due to the manifestation of such latent defects can be prevented.

[0025] Furthermore, a first insulating layer 21 is formed on the first covering layer 61, and a first conductor layer 31 is formed on the first insulating layer 21. Therefore, the first covering layer 61 and the first insulating layer 21 are interposed between the core layer 1 and the first conductor layer 31. Similarly, a second insulating layer 22 and a second conductor layer 32 are formed in that order on the second covering layer 62, and the second covering layer 62 and the second insulating layer 22 are interposed between the core layer 1 and the second conductor layer 32. Therefore, the distances between the core layer 1 and the first conductor layer 31 and the second conductor layer 32 can be longer than when the first and second insulating layers 21, 22 or the first and second covering layers 61, 62 are not formed. Therefore, even if the thermal expansion coefficients of the glass constituting the core layer 1 and the conductors constituting the first conductor layer 31 and the second conductor layer 32, such as copper, are different, it is believed that stress caused by the difference is alleviated. Therefore, it is believed that, for example, cracks in the first insulating layer 21 and / or the second insulating layer 22, and peeling at the interface between the first insulating layer 21 and the first conductor layer 31 and / or the interface between the second insulating layer 22 and the second conductor layer 32 are less likely to occur.

[0026] Furthermore, resin constituting the resin filler 5 is interposed between the core layer 1 made of glass and the through-hole conductors 4. Therefore, stress caused by the difference in thermal expansion coefficient between the core layer 1 and the through-hole conductors 4 may be reduced between the core layer 1 and the through-hole conductors 4. This may prevent cracks and interfacial peeling between the through-hole conductors 4 and the core layer 1. In this way, according to this embodiment, the quality of the wiring board 100 may be improved.

[0027] For example, the first covering layer 61 and the second covering layer 62 may be formed of a material different from the material constituting the first insulating layer 21 and the second insulating layer 22. For example, the first covering layer 61 and the second covering layer 62 may be formed of a material having a thermal expansion coefficient closer to that of the glass constituting the core layer 1 than that of the material constituting the first insulating layer 21 and the second insulating layer 22. On the other hand, the first insulating layer 21 and the second insulating layer 22 may be formed of a material that is substantially the same as the material constituting the first covering layer 61 and the second covering layer 62, or, if one or more insulating resin layers are positioned on the top surfaces of the first insulating layer 21 and the second insulating layer 22 as build-up layers, as described below, the material may be formed of a material having a thermal expansion coefficient closer to that of the insulating resin layer (e.g., the insulating layer 23 in FIG. 3B, which will be referred to later). This may further reduce stress generated within the wiring substrate 100.

[0028] For example, the thermal expansion coefficient (λ1) of the core layer 1, the thermal expansion coefficient (λ2) of the first and second covering layers 61, 62, the thermal expansion coefficient (λ3) of the first and second insulating layers 21, 22, and the thermal expansion coefficient (λ4) of the insulating resin layer that may be formed on the upper surfaces of the first insulating layer 21 and the second insulating layer 22 may have a relationship of λ1<λ2<λ3<λ4. Alternatively, λ2 and λ3 may be approximately equal, and λ1 to λ4 may have a relationship of λ1<[λ2, λ3]<λ4. Alternatively, λ3 and λ4 may be approximately equal, and λ1 to λ4 may have a relationship of λ1<λ2<[λ3, λ4].

[0029] The first insulating layer 21 and the second insulating layer 22 may be formed of a material having a lower dielectric constant and a lower dielectric loss tangent than the material forming the first covering layer 61 and the second covering layer 62. This may reduce the transmission loss of high-frequency signals in the first and second conductor layers 31 and 32, improving the transmission characteristics of high-frequency signals. On the other hand, the first covering layer 61 and the second covering layer 62 may be formed of a material selected by prioritizing good adhesion to the glass constituting the core layer 1 over a low dielectric constant or a low dielectric loss tangent. For example, the first insulating layer 21 and the second insulating layer 22 may be formed of the thermoplastic resin described above, and the first covering layer 61 and the second covering layer 62 may be formed of the thermosetting resin described above, such as an epoxy resin.

[0030] As shown in FIG. 2, the inner wall of the first through hole 11 is covered with a resin filler 5. In the example of FIG. 2, the resin filler 5 is integrally formed with the first insulating layer 21 and the second insulating layer 22. That is, the resin filler 5 is formed from a portion of the resin 20 that constitutes the first insulating layer 21 and the second insulating layer 22 and that has flowed into the first through hole 11. Therefore, in the example shown in FIGS. 1 and 2, the resin filler 5 is made of the same type of resin as the resin 20 contained in the first insulating layer 21 and the second insulating layer 22. There is no interface between the resin filler 5 and the first insulating layer 21, 22. For example, even if the through-hole conductor 4 expands or contracts, it is believed that the resin filler 5 is unlikely to peel off from the first insulating layer 21 and the second insulating layer 22.

[0031] 1 and 2, the first through hole 11 has a substantially constant width W1 from the top surface of the first covering layer 61 to the top surface of the second covering layer 62 (the surface facing away from the core layer 1) and has a columnar shape. That is, the width W1 of the first through hole 11 is substantially constant from the opening of the first through hole 11 on the first covering layer 61 side to the opening of the first through hole 11 on the second covering layer 62 side. Also, the second through hole 52 has a substantially constant width W2 from the opening on the first insulating layer 21 side to the opening on the second insulating layer 22 side and has a columnar shape. That is, the width W2 of the second through hole 52 (which is also the width of the through-hole conductor 4 in the example of FIG. 2) is substantially constant from the end on the first conductor layer 31 side to the end on the second conductor layer 32 side. For example, even if a load is applied to the through-hole conductor 4 in the Z direction, it is thought that stress is unlikely to concentrate at a specific position of the through-hole conductor 4 in the Z direction.

[0032] The width W1 of the first through hole 11 and the width W2 of the second through hole 52 are the distances between the two most distant points on the outer periphery of the cross section of each of the first through hole 11 and the second through hole 52 perpendicular to the Z direction. The first through hole 11, the second through hole 52, and the through-hole conductor 4 in the example of FIG. 2 may have any cross-sectional shape, such as a circle, in the cross section perpendicular to the Z direction. Therefore, the first through hole 11, the second through hole 52, and the through-hole conductor 4 in the example of FIG. 2 may be columnar bodies having any shape in the cross section perpendicular to the axial direction.

[0033] The width W1 of the first through hole 11 and the width W2 of the second through hole 52 being "substantially constant" means that the variation in the width W1 and width W2 from one end to the other end in the Z direction of the first through hole 11 and the second through hole 52 is 10% or less.

[0034] The width W1 of the first through hole 11 is, for example, 60 μm or more and 400 μm or less. The width W2 of the second through hole 52 is, for example, 30 μm or more and 200 μm or less. The through-hole conductor 4 and the inner wall of the first through hole 11 are separated by a distance L1. That is, a resin filler 5 having a thickness corresponding to the distance L1 is interposed between the through-hole conductor 4 and the inner wall of the first through hole 11 (for example, the end face of the core layer 1 exposed in the first through hole 11). The distance L1 is, for example, 15 μm or more and 100 μm or less. When the distance L1 is ensured at this level, it is believed that contact between the through-hole conductor 4 and the core layer 1 can be avoided even if the formation position of the second through hole 52 varies during manufacturing.

[0035] 3A and 3B show wiring boards 200 and 300, respectively, which are other examples of the wiring board 100 of this embodiment. The wiring board 200 shown in FIG. 3A differs from the wiring board 100 illustrated in FIG. 1 in the shape of the through-hole conductor 4. The width of the second through hole 52 in the wiring board 200 decreases from the end on the first conductor layer 31 side and the end on the second conductor layer 32 side toward the center of the core layer 1 in the Z direction. The second through hole 52 has its narrowest width at approximately the center in the Z direction. Therefore, the second through hole 52 and the through-hole conductor 4 filling the second through hole 52 in the example of FIG. 3A have their narrowest width (constriction) at their center in the Z direction. The second through hole 52 formed to have the through-hole conductor 4 having the shape illustrated in FIG. 3A may be formed in a shorter time and / or with a smaller width, if necessary, than the second through hole 52 in the wiring board 100 illustrated in FIG. 1.

[0036] As shown in FIG. 3A, the width W3 at each end of the second through hole 52, which has a constriction in the center in the Z direction, is, for example, 50 μm or more and 200 μm or less. The width W4 at the narrowest portion of the second through hole 52, such as the center in the Z direction, is, for example, approximately 30 μm to 180 μm. The minimum thickness of the resin filler 5 interposed between the through-hole conductor 4 and the inner wall of the first through hole 11, i.e., the shortest distance L2 between the through-hole conductor 4 and the inner wall of the first through hole 11, is, for example, approximately 10 μm. The wiring board 200 shown in FIG. 3A has a similar structure and includes similar components to the wiring board 100 shown in FIG. 1, except for the shapes of the through-hole conductor 4 and the second through hole 52. In FIG. 3A, components similar to those included in the wiring board 100 shown in FIG. 1 are denoted by the same reference numerals as those in FIG. 1 or omitted as appropriate, and redundant descriptions of those components will be omitted.

[0037] 3B includes a core substrate 301 and buildup layers 302, 303, each including a plurality of pairs of conductor layers and insulating layers, formed on both sides of the core substrate 301. The core substrate 301 of the wiring substrate 300 illustrated in FIG. 3B is the wiring substrate 100 shown in FIG. 1. Therefore, the core substrate 301 includes a core layer 1 made of glass, a first covering layer 61 and a second covering layer 62, a first insulating layer 21 and a second insulating layer 22, a first conductor layer 31 and a second conductor layer 32, and through-hole conductors 4.

[0038] The buildup layer 302 is laminated on a first insulating layer 21 and a first conductor layer 31 that cover the first surface 1a of the core layer 1. The buildup layer 303 is laminated on a second insulating layer 22 and a second conductor layer 32 that cover the second surface 1b of the core layer 1. The buildup layer 302 and the buildup layer 303 each include two pairs of an insulating layer 23 and a conductor layer 33 that are laminated in this order on the core substrate 301. The insulating layer 23 has via conductors 41 formed therein that penetrate the insulating layer 23 and connect the conductor layers on both sides of it.

[0039] Like the first and second insulating layers 21 and 22, the insulating layer 23 is formed of any insulating resin. Examples of insulating resins include thermosetting resins such as epoxy resin, BT resin, and phenolic resin, and thermoplastic resins such as fluororesin, LCP, PTFE, PE, and MPI. In the example of FIG. 3B, the insulating layer 23 does not include the reinforcing material 2a (see FIG. 1) included in the first insulating layer 21, but the insulating layer 23 may include a reinforcing material formed of glass fiber, aramid fiber, or the like. The insulating layer 23 may further include a filler (not shown) made of particles such as silicon dioxide or alumina. The insulating layer 23 is formed, for example, by laminating a film of epoxy resin onto the core substrate 301 or onto the already formed insulating layer 23 and conductor layer 33, followed by thermocompression bonding.

[0040] The conductor layer 33 and the via conductors 41 may be formed using any metal such as copper or nickel, similar to the first conductor layer 31 and the through-hole conductors 4. The conductor layer 33 and the via conductors 41 may have a multilayer structure including, for example, an electroless plated film and an electrolytic plated film. The conductor layer 33 and the via conductors 41 may be formed by any method, such as a semi-additive method, a full-additive method, or a subtractive method. A solder resist (not shown) may be formed on the outermost insulating layer 23 and the conductor layer 33.

[0041] As described above, the wiring board of the embodiment may further include one or more pairs of insulating layer 23 and conductor layer 33 on first insulating layer 21 and first conductor layer 31 provided on first surface 1a of core layer 1 made of glass. Furthermore, the wiring board of the embodiment may further include one or more pairs of insulating layer 23 and conductor layer 33 on second insulating layer 22 and second conductor layer 32 provided on second surface 1b of core layer 1. That is, the wiring board of the embodiment may be a multilayer wiring board including core substrate 301 containing glass and one or more conductor layers, as in wiring board 300 shown in FIG. 3B .

[0042] Furthermore, the wiring board of the embodiment may be a core substrate of a multilayer wiring board in which one or more pairs of insulating layers and conductor layers are formed on each side by a build-up method, such as wiring board 100 in the example of Figure 1 which functions as core substrate 301 in the example of Figure 3B.

[0043] FIG. 3C shows another example of a through-hole conductor in the wiring board 100 of one embodiment. The through-hole conductor 4a shown in FIG. 3C is located at least on the inner wall of the second through hole 52, similar to the through-hole conductor 4 in the example of FIG. 2 . However, the through-hole conductor 4a does not completely fill the second through hole 52. That is, the second metal film 3c constituting the through-hole conductor 4a, together with the first metal film 3b, covers the sidewall of the second through hole 52 but does not fill the entire second through hole 52. The portion of the second through hole 52 that is inside the second metal film 3c is filled with a hole-filling resin 53. The hole-filling resin 53 can be formed by filling the unfilled portion of the second through hole 52 with an appropriate resin, such as an epoxy resin, after the second metal film 3c is formed and then curing the resin.

[0044] In the example of FIG. 3C , a third metal film 3d is further formed on the second metal film 3c and on the hole-filling resin body 53, and a fourth metal film 3e is formed on the third metal film 3d. The third metal film 3d can be formed, for example, by electroless plating or sputtering, and the fourth metal film 3e can be formed, for example, by electrolytic plating using the third metal film 3d as a power supply layer. The third metal film 3d and the fourth metal film 3e form a so-called cap plating of the through-hole conductor 4a. The conductor layer 31 and the conductor layer 32 in the example of FIG. 3C are respectively composed of a metal foil 3a, a first metal film 3b, a second metal film 3c, a third metal film 3d, and a fourth metal film 3e. In this embodiment, as in the example of FIG. 3C , the through-hole conductor does not have to completely fill the second through-hole and may have, for example, a cylindrical shape. The interior of the through-hole conductor may be filled with resin.

[0045] 4 shows a wiring board 400, which is an example of a wiring board according to another embodiment of the present invention. Wiring board 400 differs from wiring board 100 according to the embodiment shown in FIG. 1 and the like in that wiring board 400 includes conductor layer 34 (third conductor layer) and conductor layer 35 (fourth conductor layer), as well as via conductors 42 and 43.

[0046] The conductor layer 34 is provided on the first covering layer 61. The conductor layer 35 is provided on the second covering layer 62. The conductor layer 34 and the conductor layer 35 have a desired conductor pattern. Like the first and second conductor layers 31 and 32, the conductor layer 34 and the conductor layer 35 are formed of any metal, such as copper or nickel. The conductor layers 34 and 35 may have a single-layer structure or a multi-layer structure including two or more layers. The conductor layers 34 and 35 may include, for example, only a metal foil, or may include a metal foil and a plating film.

[0047] Via conductor 42 is provided on the first surface 1a side of core layer 1, and via conductor 43 is provided on the second surface 1b side. Via conductor 42 penetrates first insulating layer 21 to connect first conductor layer 31 and conductor layer 34. Via conductor 43 penetrates second insulating layer 22 to connect second conductor layer 32 and conductor layer 35. Via conductor 42 is formed integrally with first conductor layer 31. Therefore, via conductor 42 may include an electroless plated film and an electrolytic plated film made of, for example, copper or nickel, which constitute first conductor layer 31. Via conductor 43 is formed integrally with second conductor layer 32. Therefore, via conductor 43 may include an electroless plated film and an electrolytic plated film made of, for example, copper or nickel, which constitute second conductor layer 32.

[0048] As described above, the wiring board of the embodiment may include conductor layers 34 and 35 formed on the first covering layer 61 and the second covering layer 62, respectively. Additionally, the wiring board of the embodiment may include via conductors 42 connecting the conductor layer 34 and the first conductor layer 31, and via conductors 43 connecting the conductor layer 35 and the second conductor layer 32. By providing the conductor layers 34, 35, the via conductors 42, and the via conductors 43, it may be possible to incorporate a larger-scale electrical circuit inside the wiring board 400. Furthermore, the wiring rules required for the first conductor layer 31 and the second conductor layer 32 may be relaxed, improving manufacturing yield. Note that only the conductor layers 34 and 35 may be provided without the via conductors 42 and 43, or only one of the conductor layers 34 and 35 may be provided.

[0049] 4, the first insulating layer 21 and the second insulating layer 22 do not include the reinforcing material 2a that is included in the first and second insulating layers 21, 22 of the wiring board 100 illustrated in FIG. 1. In the wiring board of the embodiment, the first insulating layer 21 and the second insulating layer 22 do not necessarily include the reinforcing material 2a (see FIG. 1). If a reinforcing material is not included, it may be easier to form an electroless plated film when forming the first conductor layer 31 and the second conductor layer 32.

[0050] 4 has the same structure and includes the same components as wiring board 100 in the example of Fig. 1, except that wiring board 400 shown in Fig. 4 includes conductor layer 34, conductor layer 35, via conductor 42, and via conductor 43, and does not include a reinforcing material. In Fig. 4, components similar to those included in wiring board 100 in Fig. 1 are assigned the same reference numerals as those assigned in Fig. 1 or are omitted as appropriate, and repeated explanations of those components will be omitted.

[0051] A method for manufacturing a wiring board according to one embodiment will be described with reference to FIGS. 5A to 5I, taking as an example the case where wiring board 100 shown in FIG. 1 is manufactured.

[0052] 5A and 5B, the method for manufacturing a wiring board according to this embodiment includes preparing a glass plate that constitutes core layer 1 of wiring board 100 shown in FIG. 1. In the description of the method for manufacturing a wiring board according to this embodiment, the glass plate shown in FIG. 5A that constitutes core layer 1 of wiring board 100 is also referred to as "glass plate 1" with the reference number "1" for core layer 1 affixed. As shown in FIG. 5A, glass plate 1 includes two opposing main surfaces (first surface 1a and second surface 1b) that are perpendicular to its thickness direction.

[0053] As described above, the glass plate 1 is prepared from a glass plate made of, for example, soda-lime glass, alkali-free glass, quartz glass, or borosilicate glass. The glass plate 1 can be prepared by a common glass plate manufacturing method, such as the float glass method. The glass plate 1 may also be prepared from a glass plate made of organic glass, such as acrylic glass. However, in this embodiment, even when a glass plate 1 made of silicate glass, such as soda-lime glass, which is considered to have low toughness and low resistance to mechanical impact, is used, breakage of the glass plate 1 may be suppressed, as will be described later.

[0054] In this embodiment, as shown in Figures 5A and 5B, a glass plate 1 is prepared in which a first surface 1a, a second surface 1b opposite to the first surface 1a, and a side surface 1c between the first surface 1a and the second surface 1b are covered with a coating material 601. For example, a glass plate 1 is prepared in which the entire first surface 1a and the second surface 1b and some or all of the side surface 1c are covered with the coating material 601. Since most of the surface of the glass plate 1 is covered with the coating material 601, the glass plate 1 is protected from mechanical shocks that may be applied from the outside in later processes. Preferably, a glass plate 1 in which all surfaces are covered with the coating material 601 is prepared.

[0055] A glass plate 1, whose first surface 1a, second surface 1b, and side surface 1c are covered with a covering material 601, is prepared by laminating a resin sheet 600 made of a B-stage resin formed into a sheet shape onto the glass plate 1, as shown in FIG. 5A. In the example of FIG. 5A, the glass plate 1 is placed in a hollow portion 71 of a frame-shaped plate 7. The resin sheet 600 is also laminated on top of the frame-shaped plate 7. The frame-shaped plate 7 includes a hollow portion 71, which is a through-hole penetrating the frame-shaped plate 7, and a frame portion 72 surrounding the hollow portion 71. The frame portion 72 is formed of any material, such as epoxy resin. The frame portion 72 may be made of the same material as the resin sheet 600. The frame portion 72 shown in FIG. 5A includes a reinforcing material 73 made of glass fiber, aramid fiber, or the like.

[0056] In the example shown in FIGS. 5A and 5B, the covering material 601 includes a reinforcing material 6a and a resin 60 impregnated in the reinforcing material 6a. Examples of the reinforcing material 6a include, but are not limited to, glass fiber and aramid fiber. Examples of the resin 60 include, but are not limited to, thermosetting resins such as epoxy resin, BT resin, and phenolic resin, and thermoplastic resins such as fluororesin, LCP, PTFE, PE, and MPI. The resin sheet 600 includes the reinforcing material 6a and the resin 60 impregnated in the reinforcing material 6a. The resin sheet 600 may be a so-called prepreg formed by impregnating a reinforcing material 6a, such as glass fiber, with an epoxy resin. As shown in FIG. 5A, a resin sheet 600 larger than the glass plate 1 in plan view is prepared. The resin sheet 600 is then laminated on each of the first surface 1a and the second surface 1b of the glass plate 1 and on the frame portion 72 of the frame-shaped plate 7.

[0057] In the example of FIG. 5A , a metal foil 3d is laminated on one surface 60a of a resin sheet 600. The resin sheet 600 is laminated on the glass plate 1 with the surface opposite to the one surface 60a facing the glass plate 1. The resin sheets 600 laminated on both surfaces of the glass plate 1 are heated and pressurized. The heating and pressurization temporarily softens the resin 60, and the resin 60 is pressure-bonded to the glass plate 1 and the frame-shaped plate 7. The surface of the resin sheet 600 opposite to the metal foil 3d is joined to the glass plate 1. When the metal foil 3d is laminated on the resin sheet 600, it may be easier to thermocompress the resin sheet 600.

[0058] The resin 60 softened by heating further flows down along the side surface 1c from each of the first surface 1a and the second surface 1b to the opposite surface. The side surface 1c is then covered with the resin 60. The gap between the frame plate 7 and the glass plate 1 is also filled with the resin 60. In this state, the resin 60 hardens to the C-stage. As a result, as shown in FIG. 5B, a glass plate 1 is obtained whose first surface 1a, second surface 1b, and side surface 1c are covered with the coating material 601. The obtained glass plate 1 is surrounded by the frame plate 7. A first coating layer 61 is formed on the first surface 1a of the glass plate 1. The first coating layer 61 is composed of a portion of the coating material 601 that covers the first surface 1a. A second coating layer 62 is formed on the second surface 1b of the glass plate 1. The second coating layer 62 is composed of a portion of the coating material 601 that covers the second surface 1b. The first coating layer 61 and the second coating layer 62 also cover the surface of the frame plate 7. When the side surface 1c is covered with the resin 60, the softened resin 60 may flow out of the metal foil 3d and protrude. In this case, after the resin 60 (coating material 601) has hardened to the C stage, the protruding portion can be cut or removed by router processing or edge polishing.

[0059] Thus, in this embodiment, preparing the glass plate 1 may include bonding a resin sheet 600 containing the reinforcing material 6a and the resin 60 impregnated in the reinforcing material 6a to each of the first surface 1a and the second surface 1b of the glass plate 1. Furthermore, preparing the glass plate 1 may include covering the side surface 1c of the glass plate 1 with a portion of the resin 60 contained in the resin sheet 600. When the wiring board 100 of FIG. 1 is manufactured, after the resin sheet 600 is thermocompression bonded, the metal foil 3d is removed, for example, by etching.

[0060] As shown in FIG. 5C, the method for manufacturing a wiring board according to this embodiment includes forming a first through hole 11 that penetrates the glass plate 1, the first covering layer 61, and the second covering layer 62. The first through hole 11 is formed by any method, such as drilling or laser processing using a carbon dioxide laser or other laser beam. In the example of FIG. 5C, the first through hole 11 has a substantially constant width from the first covering layer 61 side to the second covering layer 62 side and has a columnar shape. For example, drilling can easily form a first through hole 11 that has a substantially constant width over the entire length in the axial direction (Z direction).

[0061] In this embodiment, the first surface 1a and the second surface 1b of the glass plate 1 are covered with a first coating layer 61 and a second coating layer 62, respectively. Therefore, drilling of the first through hole 11 starts from the surface of the first coating layer 61 and / or the second coating layer 62, rather than from the surface of the glass plate 1. When a drill bit (not shown) first contacts the hard surface of glass, the drill bit does not immediately penetrate into the glass plate 1, which can result in misalignment. However, in this embodiment, drilling starts from the first coating layer 61 and / or the second coating layer 62, which are mainly made of a resin that is more flexible and has excellent workability than glass. Therefore, the drill bit can quickly penetrate into the first coating layer 61 and / or the second coating layer 62, and therefore, it is thought that misalignment is unlikely to occur. Then, by the time the drill bit reaches the glass plate 1, the opening of the first through hole 11 has already been formed in the first coating layer 61 and / or the second coating layer 62, and the drill bit is seated therein. Therefore, it is thought that the position of the drill bit is unlikely to shift, and the position of the first through hole 11 is unlikely to shift.

[0062] Furthermore, since the first through hole 11 is formed in the glass plate 1 with both sides covered by the first and second coating layers 61, 62, it is believed that the glass plate 1 is less likely to suffer damage such as breakage or cracking due to mechanical impact during drilling.

[0063] As shown in FIGS. 5C and 5D, the method for manufacturing a wiring board according to this embodiment further includes forming a first insulating layer 21 on a first covering layer 61 and forming a second insulating layer 22 on a second covering layer 62. The first insulating layer 21 and the second insulating layer 22 are formed by supplying a resin 20 onto the first covering layer 61 and the second covering layer 62, respectively. In the example shown in FIG. 5C, the resin 20 is impregnated into a reinforcing material 2a, formed into a sheet in a B-stage state, and then supplied onto the first covering layer 61 and the second covering layer 62, respectively. A metal foil 3a is further laminated on the sheet-like resin 20. The metal foil 3a is, for example, copper foil. The metal foil 3a is not limited to copper foil, but may be made of any metal having suitable conductivity, such as nickel.

[0064] Examples of the resin 20 include, but are not limited to, thermosetting resins such as epoxy resin, BT resin, and phenolic resin, and thermoplastic resins such as fluororesin, LCP, PTFE, PE, and MPI. Examples of the reinforcing material 2a include, but are not limited to, glass fiber and aramid fiber. For example, prepregs made of the resin 20 and the reinforcing material 2a are laminated on the first covering layer 61 and the second covering layer 62, respectively.

[0065] The resin 20 and the metal foil 3a supplied onto the first coating layer 61 and the second coating layer 62 are pressurized and heated at an appropriate pressure and temperature. The resin 20 is softened by the pressurization and heating, and the resin 20 is pressure-bonded to the first coating layer 61 and the second coating layer 62. As a result, a first insulating layer 21 is formed on the first coating layer 61. A second insulating layer 22 is formed on the second coating layer 62. The resin 20 and the metal foil 3a are also pressure-bonded to each other. Metal foil 3a is laminated on each of the first insulating layer 21 and the second insulating layer 22. The metal foil 3a on the first insulating layer 21 and the metal foil 3a on the second insulating layer 22 respectively constitute part of the first conductor layer 31 and the second conductor layer 32 (see FIG. 5H) that will be formed in a subsequent process. By laminating the metal foil 3a, even if the first insulating layer 21 and the second insulating layer 22 contain the reinforcing material 2a, the first metal film 3b (see Figure 5F) described below can be easily formed by electroless plating.

[0066] Resin 20 is supplied onto first covering layer 61 and second covering layer 62 and softened by heating, and then flows into first through hole 11. First through hole 11 is filled with resin 20 that has flowed into first through hole 11. As the flowed resin 20 hardens, a resin filler 5 made of resin 20 that fills first through hole 11 is formed, as shown in FIG. 5D . The method for manufacturing a wiring board according to this embodiment includes forming resin filler 5 that fills first through hole 11 in this manner. Forming resin filler 5 also includes filling first through hole 11 with a portion of resin 20 supplied onto first covering layer 61 or second covering layer 62. Glass that constitutes glass plate 1 and is exposed on the inner wall of first through hole 11 is protected by resin filler 5.

[0067] The first insulating layer 21 and the second insulating layer 22 may be formed using a material different from the coating material 601 (see FIG. 5B ) constituting the first covering layer 61 and the second covering layer 62. This allows the first insulating layer 21 and the second insulating layer 22 to have different properties from the first covering layer 61 and the second covering layer 62. For example, the first insulating layer 21 and the second insulating layer 22 may be formed using a material having a thermal expansion coefficient closer to that of an insulating resin layer of a build-up layer, such as the insulating layer 23 in the example of FIG. 3B , which may be formed in a later process, than the material forming the first covering layer 61 and the second covering layer 62. On the other hand, the first covering layer 61 and the second covering layer 62 may be formed using a material having a thermal expansion coefficient closer to that of the glass plate 1 than the material forming the first insulating layer 21 and the second insulating layer 22. This may further reduce stress generated within the wiring substrate 100.

[0068] The first insulating layer 21 and the second insulating layer 22 may be formed of a material having a lower dielectric constant and a lower dielectric loss tangent than the material forming the first covering layer 61 and the second covering layer 62. By doing so, as described above, the transmission loss of high-frequency signals in the first and second conductor layers 31, 32 (see FIG. 5H) may be reduced, and the transmission characteristics of high-frequency signals may be improved. For example, the first insulating layer 21 and the second insulating layer 22 may be formed of the thermoplastic resin described above, and the first covering layer 61 and the second covering layer 62 may be formed of the thermosetting resin described above, such as an epoxy resin.

[0069] 5E to 5H, the method for manufacturing a wiring board of this embodiment further includes forming a first conductor layer 31 on the first insulating layer 21, forming a second conductor layer 32 on the second insulating layer 22, and forming through-hole conductors 4 that connect the first conductor layer 31 and the second conductor layer 32. In the example shown in FIGS. 5E to 5H, the first conductor layer 31 and the second conductor layer 32 are formed by a semi-additive method, but the method for forming the first conductor layer 31 and the second conductor layer 32 is not limited to the semi-additive method, and any method such as a subtractive method or a full-additive method may be used.

[0070] As shown in FIG. 5E, a second through hole 52 is formed penetrating the first insulating layer 21, the second insulating layer 22, the resin filler 5, and the metal foil 3a. That is, the second through hole 52 is formed so as to pass through the inside of the first through hole 51. However, the second through hole 52 is formed so as to have an appropriate gap between it and the inner wall of the first through hole 51. A through-hole conductor 4 (see FIG. 5G) is formed in the second through hole 52. In other words, the second through hole 52 is formed at the location where the through-hole conductor 4 is to be formed. Thus, in this embodiment, forming the through-hole conductor 4 may include forming the second through hole 52 penetrating the first insulating layer 21, the second insulating layer 22, and the resin filler 5.

[0071] The second through holes 52 may be formed by any method. For example, the second through holes 52 are formed by laser processing in which laser light is irradiated using a carbon dioxide laser or the like, or by drilling. In this embodiment, the second through holes 52 are formed so as to pass through the glass plate 1 via the resin filler 5, without directly penetrating the glass plate 1. Because the hard glass plate 1 is not processed, even if a small-diameter drill bit is used to form the second through holes 52, it is thought that the drill bit will be less damaged or worn. For example, this may be particularly useful when small-diameter through-hole conductors 4 are formed to achieve fine-pitch wiring.

[0072] In addition, since the glass plate 1 is not directly pierced, it is thought that stress is less likely to be applied to the glass plate 1. Therefore, it is thought that breakage or cracking of the glass plate 1 can be suppressed, and the process yield can be improved.

[0073] Furthermore, since the second through hole 52 does not directly penetrate the glass plate 1, it is believed that the second through hole 52 can be easily formed by laser processing. By using laser processing, it may be possible to form a second through hole 52 with a smaller diameter more quickly and with greater accuracy. When the second through hole 52 is formed by laser processing, laser light may be irradiated from both the first insulating layer 21 side and the second insulating layer 22 side. By doing so, it is possible to form the second through hole 52 having a narrowest portion (a constriction) approximately at the center in the Z direction, as shown in FIG. 3A referenced above. Note that the first through hole 11 may be formed by drilling, while the second through hole 52 may be formed by laser processing.

[0074] When the second through holes 52 are formed by laser processing, the portions of the metal foil 3a where the second through holes 52 are to be formed may be removed by, for example, etching before the laser light is applied. In this case, only the portions of the second through holes 52 that penetrate the first and second insulating layers 21, 22 and the resin filler 5 are formed by laser processing. It is believed that the second through holes 52 can be formed with less laser power.

[0075] As shown in FIG. 5F, the first metal film 3b is formed on the entire surface of the metal foil 3a and the entire inner wall surface of the second through-hole 52. FIGS. 5F to 5H show enlarged views of portions corresponding to the VF portion of FIG. 5E in each step. The first metal film 3b is formed by, for example, electroless plating or sputtering. For example, the first metal film 3b is formed as a metal film made of any metal having suitable conductivity, such as copper or nickel.

[0076] 5G, a second metal film 3c is formed on the first metal film 3b. As a result, a through-hole conductor 4 is formed inside the second through hole 52. Furthermore, a first conductor layer 31 is formed on the first insulating layer 21, and a second conductor layer 32 is formed on the second insulating layer 22.

[0077] 5G, in forming the first conductor layer 31, the second conductor layer 32, and the through-hole conductor 4, a plating resist R is provided on the first metal film 3b. The plating resist R has openings R1 provided above the formation areas of the conductor patterns to be included in the first conductor layer 31 or the second conductor layer 32, and above the second through-holes 52.

[0078] Then, a second metal film 3c is formed in the opening R1 by pattern plating, including electrolytic plating using the first metal film 3b as a power supply layer. The first and second conductor layers 31 and 32 each have a three-layer structure. The second through-hole 52 is filled with the second metal film 3c to form a through-hole conductor 4. In this embodiment, forming the through-hole conductor 4 may include forming a conductor on at least the sidewall of the second through-hole 52. Furthermore, forming the through-hole conductor 4 may include filling the second through-hole 52 with a conductor such as the first metal film 3b and the second metal film 3c, as shown in FIG. 5G. The through-hole conductor 4 penetrates the resin filler 5, the first insulating layer 21, and the second insulating layer 22 to connect the first conductor layer 31 and the second conductor layer 32. The plating resist R is then removed, for example, using an appropriate solvent. Removal of the plating resist R exposes the portion of the first metal film 3b not covered by the second metal film 3c.

[0079] As shown in FIG. 5H, the portion of the first metal film 3b that is not covered by the second metal film 3c is removed, for example, by etching. As a result, a first conductor layer 31 and a second conductor layer 32 are formed, each including a predetermined conductor pattern and composed of the metal foil 3a, the first metal film 3b, and the second metal film 3c. The through-hole conductor 4 formed in the second through hole 52 is composed of the first metal film 3b and the second metal film 3c that form the first conductor layer 31 or the second conductor layer 32. Although not shown, a solder resist may be formed on the first insulating layer 21 and the first conductor layer 31 and on the second insulating layer 22 and the second conductor layer 32. The solder resist may be formed, for example, by applying a photosensitive epoxy resin or polyimide resin by spraying, laminating, printing, or the like.

[0080] As shown in FIG. 5I, the resin 60 covering the side surface 1c of the glass plate 1 and the frame-shaped plate 7 are removed. For example, by router cutting, the first insulating layer 21 and the second insulating layer 22, and the resin 60 covering the side surface 1c of the glass plate 1 are cut along the boundary between the side surface 1c of the glass plate 1 and the resin 60 covering the side surface 1c. The insulating layers 21 and 22, and the resin 60 covering the side surface 1c of the glass plate 1 can be cut by any method, such as by using a roller blade, and not limited to router cutting.

[0081] In the example of FIG. 5I, the first insulating layer 21, the second insulating layer 22, and the resin 60 are cut at a cutting position C along the side surface 1c of the glass plate 1. The cutting position C may be approximately coincident with the boundary surface between the glass plate 1 and the resin 60 covering the side surface 1c, or may be located inside the glass plate 1 from this boundary surface. By cutting the first insulating layer 21 and the like at the cutting position C, the side surface 1c of the glass plate 1 is exposed. By going through the above steps, the wiring substrate 100 shown in FIG. 1 is obtained.

[0082] 6 shows another example of the method for manufacturing the wiring board of this embodiment. In the steps of forming the first insulating layer 21 and the second insulating layer 22 previously described with reference to FIGS. 5C and 5D, the resin 20 impregnated in the reinforcing material 2a is laminated in a sheet form on the first covering layer 61 and the second covering layer 62. However, in the method for manufacturing the wiring board of this embodiment, as shown in FIG. 6, in forming the insulating layers 21 and 22, the resin 20 formed in a film shape without including the reinforcing material may be laminated on the first covering layer 61 and the second covering layer 62. This is thought to make it easier for the first through hole 11 to be sufficiently filled.

[0083] 5C and 5D, metal foil 3a was laminated on resin 20. However, as shown in Fig. 6, film-like resin 20 alone, without metal foil, may be laminated on first covering layer 61 and second covering layer 62. It may be easy to form a fine-pitch wiring pattern on first conductor layer 31 and second conductor layer 32 (see Fig. 5H).

[0084] A method for manufacturing a wiring board according to another embodiment of the present invention will be described with reference to Figures 7A and 7B. Figures 7A and 7B show an example of a wiring board in some steps according to the method for manufacturing a wiring board according to another embodiment. By the method for manufacturing a wiring board according to this embodiment, some steps of which are shown in Figures 7A and 7B, for example, the wiring board 400 shown in Figure 4 referenced above is manufactured.

[0085] In the method for manufacturing a wiring board of this embodiment, as shown in FIG. 5B, a first covering layer 61 and a second covering layer 62 each having a metal foil 3d are formed. In the embodiment described with reference to FIGS. 5C to 5I, the metal foil 3d is removed after the first covering layer 61 and the second covering layer 62 are formed. However, in this embodiment, as shown in FIG. 7A, the metal foil 3d is not completely removed, but is partially removed so that a predetermined area remains. The partially remaining metal foil 3d forms the conductor layer 34 and the conductor layer 35. In other words, the metal foil 3d is patterned so that the conductor layer 34 and the conductor layer 35 include a predetermined conductor pattern. In this way, the method for manufacturing a wiring board of this embodiment may include patterning the metal foil 3d. The metal foil 3d is patterned by any method, such as etching.

[0086] After patterning the metal foil 3d, a first insulating layer 21 and a second insulating layer 22 are formed in a manner similar to that described with reference to Figures 5C and 5D, as shown in Figure 7B. Figure 7B shows an example in which no metal foil is laminated and the first and second insulating layers 21, 22 do not include a reinforcing material, similar to the example shown in Figure 6 previously referred to.

[0087] Before or after the second through-hole 52 is formed by a method similar to that described with reference to FIG. 5E, an opening 43a is formed at the position where the via conductor 43 (see FIG. 4) will be formed. For example, by irradiating a laser beam using a carbon dioxide laser, the opening 43a is formed in each of the first insulating layer 21 and the second insulating layer 22. Then, for example, by the method described with reference to FIGS. 5F to 5H, the first conductor layer 31, the second conductor layer 32, and the through-hole conductor 4 are formed. During the formation of the first and second conductor layers 31 and 32, the opening 43a is filled with the first metal film 3b and the second metal film 3c (see FIG. 5H), forming the via conductor 43 in the opening 43a. Then, by the method described with reference to FIG. 5I, the resin 60 covering the first and second insulating layers 21 and 22 and the side surface 1c of the glass plate 1, and the frame plate 7 are removed. As a result, the wiring board 400 shown in FIG. 4 is obtained.

[0088] The wiring board of the embodiment is not limited to those having the structure illustrated in each drawing and the structure, shape, and material illustrated in this specification. As described above, the wiring board of the embodiment may have any laminated structure. The wiring board of the embodiment may include any number of conductor layers and insulating layers, as long as it includes at least a core layer made of glass and one or more pairs of insulating and conductor layers formed on both sides of the core layer. The first through hole, the second through hole, and the through-hole conductor may have any cross-sectional shape other than those shown in FIGS. 1 and 3. For example, the first through hole and / or the second through hole may be formed by irradiating one side of the core layer with laser light and may have a tapered shape that tapers continuously from one end to the other end. Furthermore, the width of the first through hole may be narrowest at approximately the center in the Z direction, or may have a narrowest point (constriction) at this center. Furthermore, the side surface of the core layer made of glass may be covered, for example, with the resin that constitutes each coating layer.

[0089] The method for manufacturing a wiring board according to the embodiment is not limited to the method described with reference to the drawings. For example, when preparing a glass plate covered with a coating material, a resin sheet not including a reinforcing material may be laminated on the glass plate to form each coating layer. Metal foil may not be laminated on the resin sheet. As described above, each conductor layer may be formed by any method. The method for manufacturing a wiring board according to the embodiment may include any additional process in addition to the processes described above, or some of the processes described above may be omitted. [Explanation of symbols]

[0090] 100, 200, 300, 400 wiring board 1 Core layer (insulating layer, glass plate) 1a 1st page 1b 2nd side 1c side 11 First through hole 20 Resin 21 First insulating layer 22 Second insulating layer 31 First conductor layer 32 Second conductor layer 3a, 3d metal foil 4, 4a through-hole conductor 5 Resin filler 52 Second through hole 60 Resin 600 Resin Sheet 60a One side 601 Covering material 61 1st coating layer 62 Second coating layer 6a, 2a, 73 reinforcement

Claims

1. a core layer made of glass and having a first surface and a second surface opposite the first surface; a first insulating layer provided on the first surface side of the core layer and containing a resin; a second insulating layer provided on the second surface side of the core layer and containing a resin; a first conductor layer formed on the first insulating layer; a second conductor layer formed on the second insulating layer; a through-hole conductor connecting the first conductor layer and the second conductor layer; A wiring board comprising: The wiring board further includes: a first covering layer provided between the first surface and the first insulating layer and covering the first surface; a second covering layer provided between the second surface and the second insulating layer and covering the second surface; a first through hole penetrating the core layer, the first coating layer, and the second coating layer; a resin filler that fills the first through hole; Including, The through-hole conductor is located at least on the side wall of a second through hole that penetrates the first insulating layer, the second insulating layer, and the resin filler.

2. 2. The wiring board according to claim 1, The resin filler is made of the same type of resin as the resin contained in the first insulating layer and the second insulating layer.

3. 2. The wiring board according to claim 1, wherein the resin filler is formed integrally with the first insulating layer and the second insulating layer.

4. 2. The wiring board according to claim 1, wherein the first covering layer and the second covering layer are formed of a material different from a material constituting the first insulating layer and the second insulating layer.

5. 2. The wiring board according to claim 1, wherein the width of the first through hole is substantially constant from the opening on the first cover layer side to the opening on the second cover layer side.

6. 2. The wiring board according to claim 1, wherein the width of the second through hole is substantially constant from the end on the first conductor layer side to the end on the second conductor layer side.

7. 2. The wiring board according to claim 1, wherein the width of the second through hole decreases from each of the end on the first conductor layer side and the end on the second conductor layer side toward the center.

8. 2. The wiring board according to claim 1, wherein the first covering layer and the second covering layer include a reinforcing material and a resin impregnated in the reinforcing material.

9. 2. The wiring board according to claim 1, wherein a side surface of the through-hole conductor is in contact with the first insulating layer, the second insulating layer, and the resin filler without being in contact with the core layer.

10. 2. The wiring board according to claim 1, wherein the through-hole conductor fills the second through hole.

11. preparing a glass plate having a first surface, a second surface opposite to the first surface, and a side surface between the first surface and the second surface covered with a coating material; forming a first through-hole penetrating through the glass plate, a first coating layer configured to cover the first surface of the coating material, and a second coating layer configured to cover the second surface of the coating material; forming a first insulating layer by dispensing a resin onto the first coating layer; forming a second insulating layer by dispensing a resin onto the second coating layer; forming a resin filler to fill the first through hole; forming a first conductor layer on the first insulating layer; forming a second conductor layer on the second insulating layer; forming a through-hole conductor that penetrates the resin filler, the first insulating layer, and the second insulating layer to connect the first conductor layer and the second conductor layer; A method for manufacturing a wiring board, comprising:

12. 12. The method for manufacturing a wiring board according to claim 11, wherein forming the through-hole conductor comprises: forming a second through hole penetrating the first insulating layer, the second insulating layer, and the resin filler; forming a conductor on at least a side wall inside the second through hole; Contains:

13. 13. The method for manufacturing a wiring board according to claim 12, wherein forming the through-hole conductor further includes filling the second through hole with the conductor.

14. 13. The method for manufacturing a wiring board according to claim 12, wherein the first through hole is formed by drilling. The second through-hole is formed by laser processing.

15. 12. The method for manufacturing a wiring board according to claim 11, The first insulating layer and the second insulating layer are formed using a material different from the coating material.

16. A method for manufacturing a wiring board as described in claim 11, wherein forming the resin filler includes filling the first through hole with a portion of the resin supplied onto the first coating layer or the second coating layer.

17. 12. The method for manufacturing a wiring board according to claim 11, wherein the glass plate is prepared by: bonding a resin sheet containing a reinforcing material and a resin impregnated in the reinforcing material to each of the first surface and the second surface of the glass plate; The method includes covering the side surface of the glass plate with a part of the resin contained in the resin sheet.

18. 18. The method for manufacturing a wiring board according to claim 17, a metal foil is laminated on one surface of the resin sheet, The resin sheet is bonded to the glass plate at the surface opposite to the metal foil.

19. 20. The method for manufacturing a wiring board according to claim 18, further comprising patterning the metal foil.

Images