Wiring board, laminated wiring board, light emitting device, and method for manufacturing light emitting device

Abstract

To improve the adhesion between a conductive member in a through hole and a substrate.SOLUTION: A wiring board 1 according to the present disclosure includes a substrate 10 having a plurality of through holes 11, a first metal wiring 20 arranged on one main surface of the substrate 10 and having a thin edge 21 that surrounds the plurality of through holes 11 in a planar view, a second metal wiring 30 arranged on the other main surface of the substrate 10, and a conductive member 40 that connects the edge 21 of the first metal wiring 20 and the second metal wiring 30 through the plurality of through holes 11.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a wiring board, a multilayer wiring board, a light emitting device, and a method for manufacturing a light emitting device. [Background technology]

[0002] Patent Document 1 discloses a circuit board in which conductive circuits are provided on both sides of an insulating substrate, and the conductive circuits are connected by conductive resin via through holes provided in the insulating substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-338668 A Summary of the Invention [Problem to be solved by the invention]

[0004] The circuit board described in Patent Document 1 has a risk of peeling at the boundary between the conductive resin and the insulating substrate due to volumetric shrinkage during hardening of the conductive resin. The present disclosure aims to improve adhesion between the conductive member in the through hole and the substrate. [Means for solving the problem]

[0005] The wiring board of the present disclosure includes: A substrate having a plurality of through holes; a first metal wiring disposed on one main surface of the base material and having a thin edge portion surrounding the plurality of through holes in a plan view; A second metal wiring disposed on the other main surface of the base material; and a conductive member that connects the edge of the first metal wiring and the second metal wiring through the plurality of through holes.

[0006] The laminated wiring board according to the present disclosure includes: The above-mentioned wiring board; Another base material is disposed on a main surface of the wiring board, the another base material being provided with a plurality of through holes and having a conductive member disposed in each of the through holes; a third metal wiring that is disposed on a main surface of the other base material opposite to a main surface on which the wiring board is disposed, and that is connected to a conductive member disposed in a through hole of the other base material; The first metal wiring and / or the second metal wiring are electrically connected to the third metal wiring via the conductive member of the other base material.

[0007] The light emitting device of the present disclosure includes: The display device includes the above-mentioned wiring board and a light source disposed on the wiring board.

[0008] The method for producing a light emitting device according to the present disclosure includes: A step of preparing the above-mentioned wiring board; and disposing a light source on the wiring board. Effect of the Invention

[0009] According to the present disclosure, it is possible to improve the adhesion between the conductive member in the through hole and the substrate. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic plan view illustrating an example of a wiring board according to an embodiment of the present disclosure. [Diagram 2] 1A to 1C are schematic cross-sectional views illustrating an example of a process for producing a light-emitting device according to an embodiment of the present disclosure. [Diagram 3] 1A to 1C are schematic cross-sectional views illustrating an example of a process for producing a light-emitting device according to an embodiment of the present disclosure. [Figure 4] 1A to 1C are schematic cross-sectional views illustrating an example of a process for producing a light-emitting device according to an embodiment of the present disclosure. [Diagram 5] 1A to 1C are schematic cross-sectional views illustrating an example of a process for producing a light-emitting device according to an embodiment of the present disclosure. [Figure 6] 1A to 1C are schematic cross-sectional views illustrating an example of a process for producing a light-emitting device according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present disclosure (a schematic cross-sectional view taken along line VII-VII in FIG. 1). [Figure 8] 1 is a schematic cross-sectional view illustrating an example of a multilayer wiring board according to an embodiment of the present disclosure. [Figure 9] 1 is a schematic cross-sectional view illustrating an example of a light-emitting device according to an embodiment of the present disclosure. [Figure 10] FIG. 11 is a schematic cross-sectional view showing an example of a modified example of a light emitting device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Knowledge and other information that formed the basis of this disclosure> As described above, in a wiring board in which metal wiring is provided on both sides of a substrate and the metal wiring is connected by a conductive member through a through hole provided in the substrate, volume shrinkage occurs when the conductive member hardens, and this volume shrinkage tends to cause peeling at the boundary between the conductive member and the substrate in the through hole. Note that the volume shrinkage of the conductive member may occur not only when the conductive member hardens during the manufacturing of the wiring board, but also due to Joule heat when a current is passed through the metal wiring during use of the wiring board.

[0012] The degree of volumetric shrinkage can be estimated by the product of (1) the shrinkage coefficient, (2) the difference in thermal expansion coefficient between the metal wiring and the conductive member, and (3) the volume of the conductive member. Here, the inventors of the present application have discovered that one way to reduce the degree of volumetric shrinkage is to reduce the volume of the conductive member.

[0013] The present disclosure has been made as a result of extensive research based on the above findings, and aims to reduce the volume of the conductive member in the through hole, thereby reducing volumetric shrinkage and improving adhesion between the conductive member and the substrate.

[0014] Specifically, the wiring board 1 of the present disclosure comprises a substrate 10 having a plurality of through holes 11, a first metal wiring 20 arranged on one main surface of the substrate 10 and having a thin edge 21 that surrounds the plurality of through holes 11 in a planar view, a second metal wiring 30 arranged on the other main surface of the substrate 10, and a conductive member 40 that connects the edge 21 of the first metal wiring 20 and the second metal wiring 30 through the plurality of through holes 11.

[0015] In this manner, in the wiring board 1 of the present disclosure, the first metal wiring 20 is disposed around the region A in which the plurality of through holes 11 are provided in a plan view. Therefore, the volume of the conductive member 40 disposed in the through hole 11 can be reduced compared to a case in which the entire region A is a single through hole. Therefore, the volumetric shrinkage of the conductive member 40 in the through hole 11 can be reduced, and the adhesion between the conductive member 40 in the through hole 11 and the substrate 10 can be improved. In addition, by filling the plurality of through holes 11 with the conductive member 40, it is also possible to disperse stress due to heat.

[0016] Hereinafter, a wiring board according to an embodiment of the present disclosure will be described with reference to the drawings (particularly, FIGS. 1 and 7). Note that the wiring board described below is intended to embody the technical idea of ​​the present disclosure, and unless otherwise specified, the present disclosure is not limited to the following.

[0017] In each drawing, the same reference numerals may be used for components having the same function. In consideration of the explanation or ease of understanding of the main points, the embodiments may be shown in several separate embodiments for convenience. Note that partial replacement or combination of the configurations shown in different embodiments is possible. In the embodiments described later, the description of matters common to the above may be omitted, and only the differences may be described. In particular, similar effects due to similar configurations will not be mentioned in each embodiment. The size and positional relationship of the components shown in each drawing may be exaggerated to clarify the explanation. An end view showing only the cut surface may be used as a cross-sectional view.

[0018] In the following description, terms indicating a specific direction or position (e.g., "upper", "lower", and other terms including these terms) may be used. However, these terms are used merely to indicate a relative direction or position in the referenced drawings. In this specification, the positional relationship expressed as "upper (or lower)" includes, for example, when there are two assumed members, a case in which the two members are in contact with each other, and a case in which the two members are not in contact with each other and one member is located above (or below) the other member.

[0019] <Wiring Board According to an Embodiment of the Present Disclosure> 1 and 7, a wiring board 1 according to an embodiment of the present disclosure includes a base material 10, a first metal wiring 20, a second metal wiring 30, and a conductive member 40. Each component will be described in detail below.

[0020] (base material) As shown in Figs. 1 and 7, the substrate 10 has a first metal wiring 20 on one main surface and a second metal wiring 30 on the other main surface opposite to the one main surface. The substrate 10 may be a member that electrically insulates the first metal wiring 20 and the second metal wiring 30. The substrate 10 may be a member having flexibility or a member having appropriate strength. The material of the substrate 10 may be any material having insulating properties, such as resin (e.g., polyimide resin, etc.) and ceramic (e.g., silicon nitride, aluminum nitride, etc.). In this specification, "insulating" means that the electrical resistance is 1 MΩ or more, preferably 10 MΩ or more. The substrate 10 may be a single layer or a multi-layer. As an example of a multi-layer, an adhesive layer (e.g., epoxy resin, acrylic resin, etc.) that improves adhesion with the metal wiring may be arranged on both sides of a resin layer. The thickness of the substrate 10 may be, for example, 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

[0021] As shown in FIG. 7, the base material 10 may have a plurality of through holes 11 in the region A surrounded by the first metal wiring 20. In this embodiment, nine through holes 11 are provided in the base material 10 in plan view as shown in FIG. 1. The diameter of the through hole 11 may be, for example, 30 μm or more and 300 μm or less. Therefore, the volume of the through hole 11 in the wiring board 1 of the present disclosure is reduced compared to the case where one through hole 11 is provided throughout the entire region A. If one through hole is not formed throughout the entire region A surrounded by the first metal wiring 20, one through hole may be provided in a part of the region A to reduce the volume of the through hole, but it is preferable to provide a plurality of through holes 11 (two or more) from the viewpoint of wiring resistance, wiring reliability, etc. The shape of the through hole 11 is not limited to a circle in plan view. For example, it may be a rectangle, a polygon, or an ellipse in plan view.

[0022] (1st metal wiring) The first metal wiring 20 is disposed on one main surface of the base material 10. The thickness of the first metal wiring 20 may be, for example, 5 μm or more and 50 μm or less. An example of the first metal wiring 20 is Cu (copper), but is not limited to this material. In the wiring board 1 shown in FIGS. 1 and 7, the first metal wiring 20 on one side and the first metal wiring 20 on the other side may be electrically insulated by an insulating member 50 in a plan view. For example, the first metal wiring 20 on one side may be a positive wiring, and the first metal wiring 20 on the other side may be a negative wiring. In order to prevent a short circuit, the insulating member 50 may cover the first metal wiring 20 except for a portion used for connecting to a light source disposed on the wiring board 1.

[0023] The first metal wiring 20 has a thin edge portion 21 surrounding the periphery of the plurality of through holes 11 in a plan view. The "thin edge portion" as used in this specification means that the thickness of the edge portion 21 is thinner than the thickness of the portion of the first metal wiring 20 other than the edge portion 21. More specifically, the thickness of the edge portion 21 is preferably 30% or more thinner than the thickness of the portion of the first metal wiring 20 other than the edge portion 21. By making the edge portion 21 thinner than the portion of the first metal wiring 20 other than the edge portion 21 in this manner, it is possible to easily supply the conductive member 40 toward the through hole 11. In other words, the edge portion 21 acts to guide the conductive member 40 toward the through hole 11, and the filling property of the conductive member 40 in the through hole 11 can be improved.

[0024] Edge portion 21 may be spaced apart from through hole 11. That is, in region A, base material 10 may be exposed, and there may be a step between base material 10 and edge portion 21 of first metal wiring 20. According to such a configuration, the step between edge portion 21 and base material 10 further guides the conductive member toward through hole 11, and the filling property of conductive member 40 in through hole 11 can be further improved.

[0025] The thickness of edge portion 21 may become thinner toward the plurality of through holes 11. Specifically, the thickness of edge portion 21 may become thinner in stages toward through holes 11, or may become thinner in an inclined manner. With such a configuration, the conductive member can be smoothly guided toward through holes 11, and the filling property of conductive member 40 in through holes 11 can be further improved.

[0026] (Second metal wiring) The second metal wiring 30 is disposed on the other main surface of the base material 10. The thickness of the second metal wiring 30 may be, for example, 5 μm or more and 50 μm or less. An example of the second metal wiring 30 is Cu (copper), but is not limited to this material. The same metal as the first metal wiring 20 may be used, or a different metal may be used. In the wiring board shown in FIGS. 1 and 7, the second metal wiring 30 on one side and the second metal wiring 30 on the other side may be electrically insulated by an insulating member 50 in a plan view. For example, the second metal wiring 30 on one side may be a positive electrode wiring, and the second metal wiring 30 on the other side may be a negative electrode wiring.

[0027] The second metal wiring 30 may overlap with a plurality of through holes 11 in a plan view. With such a configuration, the volume of the conductive member 40 that electrically connects the second metal wiring 30 and the first metal wiring 20 can be made smaller, and the volumetric shrinkage of the conductive member 40 in the through hole 11 can be effectively reduced.

[0028] (Conductive material) The conductive member 40 is a member that connects the edge portion 21 of the first metal wiring 20 and the second metal wiring 30 through a plurality of through holes 11. The conductive member 40 may be formed by hardening a conductive paste. The upper surface of the conductive member 40 may be lower than the upper surface of the portion of the first metal wiring 20 other than the edge portion 21. The upper surface of the conductive member 40 may be higher than the upper surface of the portion of the first metal wiring 20 other than the edge portion 21, and a part of the conductive member 40 may straddle the upper surface of the first metal wiring 20. The conductive member 40 may be covered with the insulating member 50 described above.

[0029] As described above, according to the wiring board of the present disclosure, the volumetric shrinkage of the conductive member 40 in the through hole 11 can be effectively reduced, and the adhesion between the conductive member 40 in the through hole 11 and the substrate 10 can be improved.

[0030] <Laminated wiring board according to an embodiment of the present disclosure> As shown in FIG. 8, a laminated wiring board 2 according to one embodiment of the present disclosure comprises the above-mentioned wiring board 1, another substrate 10a arranged on a main surface of the wiring board 1, having a plurality of through holes 11 with a conductive member 40 arranged in each of the through holes 11, and a third metal wiring 60 arranged on a main surface of the other substrate 10a opposite to the main surface on which the wiring board 1 is arranged and connected to the conductive member 40 arranged in the through hole 11 of the other substrate 10a, and the first metal wiring 20 and / or the second metal wiring 30 are electrically connected to the third metal wiring 60 via the conductive member 40 of the other substrate 10a.

[0031] The other base material 10a may have substantially the same configuration as the base material 10 described in the wiring board 1. The multiple through holes 11 in the other base material 10a may be provided on the first metal wirings 20.

[0032] In the multilayer wiring board 2 shown in FIG. 8, the conductive members 40 arranged in the multiple through holes 11 of the other base material 10a are directly connected to the first metal wiring 20. Note that this configuration is not limited to this, and the conductive members 40 of the other base material 10a and the first metal wiring 20 may be indirectly electrically connected via the other metal wiring. In addition, the multilayer wiring board 2 shown in FIG. 8 is in the form of a multilayer wiring board with two layers, which shows a form in which one other base material 10a and a third metal wiring are arranged on the wiring board 1, but the number of layers is not limited to this form and may be three or more layers.

[0033] In the laminated wiring board 2 of the present disclosure, a first metal wiring 20 is arranged around a region A in which a plurality of through holes 11 are provided in a plan view. Furthermore, a third metal wiring 60 is arranged around a region B in which a plurality of through holes 11 are provided in a plan view. Therefore, the volume of the conductive member 40 arranged in the through hole 11 can be reduced compared to a case in which the entire regions A and B are made into through holes. Therefore, the volumetric shrinkage of the conductive member 40 in the through hole 11 can be reduced, and the adhesion between the conductive member 40 in the through hole 11 and the substrate 10 can be improved.

[0034] <Light-emitting device according to an embodiment of the present disclosure> As shown in FIGS. 9 and 10, the light emitting device 3 according to an embodiment of the present disclosure includes the above-mentioned wiring board 1 and the light source 70 arranged on the wiring board 1. The light source 70 may be an LED element or an LED package in which an LED element is packaged. For example, electronic components such as a Zener diode and a driver IC may be arranged on the wiring board 1. In addition, the supply of power from the outside may be performed from the surface of the wiring board 1 opposite to the mounting surface of the light source 70, as shown in FIG. 9. In addition, the supply of power from the outside may be performed from the mounting surface of the wiring board 1 on which the light source 70 is mounted, as shown in FIG. 10. When the supply of power from the outside is performed from the mounting surface of the light source 70 on the wiring board 1, the surface of the wiring board 1 opposite to the mounting surface of the light source 70 may be covered with an insulating member 50 to prevent a short circuit.

[0035] As described above, the light emitting device according to the present disclosure includes the above-mentioned wiring board, and therefore can improve the adhesion between the conductive member 40 and the base material 10. Note that, in the light emitting device according to the present disclosure, a configuration in which the light source 70 is disposed on the above-mentioned wiring board 1 has been described, but the present disclosure is not limited to this configuration, and the light source 70 may be disposed on the above-mentioned laminated wiring board 2.

[0036] <Method of manufacturing a light-emitting device according to an embodiment of the present disclosure> The method for manufacturing a light emitting device according to the present disclosure includes the steps of preparing the wiring board and arranging a light source on the wiring board. The manufacturing steps will be described in detail below with reference to FIGS.

[0037] (Process of preparing a wiring board) 2, a first metal wiring 20 is provided on one main surface of a substrate 10, and a second metal wiring 30 is provided on the other main surface of the substrate 10. The first metal wiring 20 and the second metal wiring 30 can be formed by a sputtering method, a vacuum deposition method, a plating method, or the like. The first metal wiring 20 and the second metal wiring 30 may be provided on the substrate 10 via the above-mentioned adhesion layer.

[0038] Next, the first metal wiring 20 is processed to form a thin edge portion 21 surrounding the positive wiring of the first metal wiring 20, the negative wiring of the first metal wiring 20, and the region A in which the multiple through holes are provided in a plan view. The first metal wiring 20 may be processed by an etching method using a photoresist as a mask. As an example, first, etching is performed while masking the area other than the region A in which the multiple through holes are provided, and then etching is performed while masking the area other than the region A and the edge portion 21, thereby forming the edge portion 21 in the first metal wiring 20 as shown in FIG. 3.

[0039] Next, a plurality of through holes 11 are formed in the region A of the base material 10. The substrate 10 may be processed by an etching method using a photoresist as a mask. As a result, a plurality of through holes 11 are formed in the region A of the substrate 10 as shown in FIG. 4. After the etching is completed, surface cleaning etching may be performed to remove surface oxide on the edge portion 21 of the first metal wiring 20. By performing surface etching on the edge portion 21, the surface oxide can be removed, and furthermore, unevenness can be provided on the edge portion 21. The conductive member 40 described later enters the unevenness, and the adhesion between the first metal wiring 20 and the conductive member 40 can be improved.

[0040] Next, the through holes 11 are filled with the conductive member 40. For example, the screen printing technique is used to fill the conductive member 40. When the conductive material constituting the conductive member 40 is filled into the through holes 11 by the screen printing technique, if the screen mask and the substrate 10 are separated, the conductive material is difficult to fill into the through holes 11. Therefore, in the manufacturing method disclosed herein, the edge portion 21 is formed on the first metal wiring 20, and the conductive material is guided toward the through holes 11 by the edge portion 21, thereby improving the filling property of the conductive material in the through holes 11. By filling the through holes 11 with the conductive material, the edge portion 21 of the first metal wiring 20 and the second metal wiring 30 are electrically connected through the multiple through holes 11.

[0041] Next, as shown in Fig. 5, the conductive material is cured to produce the conductive member 40. In the manufacturing method of the present disclosure, the first metal wiring 20 is provided around the region A in which the plurality of through holes 11 are provided in a plan view. Therefore, the volume of the conductive member 40 provided in the through hole 11 can be reduced compared to the case where the entire region A is made into through holes. Therefore, the volumetric shrinkage of the conductive member 40 in the through hole 11 can be reduced, and the adhesion between the conductive member 40 in the through hole 11 and the substrate 10 can be improved.

[0042] Next, the second metal wiring 30 is processed to form a positive wiring of the second metal wiring 30 and a negative wiring of the second metal wiring 30 as shown in Fig. 6. The second metal wiring 30 may be processed by an etching method using a photoresist as a mask.

[0043] 7, the wiring board 1 is covered with an insulating member 50 to prevent short circuits, except for the electrical connection portion with the light source 70 mounted thereon and the portion to which power is supplied from the outside. Through the above steps, the wiring board is prepared.

[0044] (Process of placing a light source on a wiring board) The light source 70 is placed on the prepared wiring board 1. Specifically, as shown in Figures 9 and 10, the electrodes of the light source 70 are aligned with the positions where the first metal wiring 20 is exposed from the insulating member 50, and the light source 70 is placed on the wiring board 1 using a conductive adhesive (for example, solder).

[0045] As described above, in the manufacturing method of the light emitting device 3 of the present disclosure, the first metal wiring 20 is provided around the region A in which a plurality of through holes 11 are provided in a plan view. Therefore, the volume of the conductive member 40 provided in the through hole 11 can be reduced compared to the case where the entire region A is provided with one through hole. Therefore, the volumetric shrinkage of the conductive member 40 in the through hole 11 can be reduced, and the adhesion between the conductive member 40 in the through hole 11 and the substrate 10 can be improved.

[0046] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure is not interpreted solely by the above-described embodiments, but is defined based on the claims. The technical scope of the present disclosure also includes all modifications within the scope and meaning equivalent to the claims.

[0047] The present disclosure includes the following embodiments. [Section 1] A substrate having a plurality of through holes; a first metal wiring disposed on one main surface of the base material and having a thin edge portion surrounding the plurality of through holes in a plan view; A second metal wiring disposed on the other main surface of the base material; a conductive member that connects an edge of the first metal wiring and the second metal wiring through the plurality of through holes. [Section 2] The wiring board according to [Item 1], wherein an edge of the first metal wiring is separated from the plurality of through holes. [Section 3] The wiring board according to [Item 1] or [Item 2], wherein the second metal wiring overlaps with the plurality of through holes in a plan view. [Section 4] The wiring board according to any one of [Item 1] to [Item 3], wherein the thickness of the edge portion becomes thinner toward the plurality of through holes. [Section 5] A wiring board according to any one of [Item 1] to [Item 4], Another base material is disposed on a main surface of the wiring board, the another base material being provided with a plurality of through holes and having a conductive member disposed in each of the through holes; a third metal wiring that is disposed on a main surface of the other base material opposite to a main surface on which the wiring board is disposed, and that is connected to a conductive member disposed in a through hole of the other base material; A laminated wiring board, wherein the first metal wiring and / or the second metal wiring is electrically connected to the third metal wiring via a conductive member of the other base material. [Section 6] A light emitting device comprising: a wiring board according to any one of [Item 1] to [Item 4]; and a light source disposed on the wiring board. [Section 7] A step of preparing a wiring board according to any one of [Item 1] to [Item 4]; and arranging a light source on the wiring board. [Explanation of symbols]

[0048] 1. Wiring board 2. Multilayer wiring board 3. Light-emitting device 10 Base material 10a Other substrates 11 Through hole 20 1st metal wiring 21 Edge 30 2nd metal wiring 40 Conductive materials 50 Insulating material 60 Third metal wiring 70 light source Area A B area

Claims

1. A substrate having a plurality of through holes; a first metal wiring disposed on one main surface of the base material and having a thin edge portion surrounding the plurality of through holes in a plan view; A second metal wiring disposed on the other main surface of the base material; a conductive member that connects an edge of the first metal wiring and the second metal wiring through the plurality of through holes.

2. The wiring board according to claim 1 , wherein an edge of the first metal wiring is spaced apart from the plurality of through holes.

3. The wiring board according to claim 1 , wherein the second metal wiring overlaps with the plurality of through holes in a plan view.

4. The wiring board according to claim 1 , wherein a thickness of the edge portion becomes thinner toward the plurality of through holes.

5. The wiring board according to claim 1 ; Another base material is disposed on a main surface of the wiring board, the another base material being provided with a plurality of through holes and having a conductive member disposed in each of the through holes; a third metal wiring that is disposed on a main surface of the other base material opposite to a main surface on which the wiring board is disposed, and that is connected to a conductive member disposed in a through hole of the other base material; A laminated wiring board, wherein the first metal wiring and / or the second metal wiring are electrically connected to the third metal wiring via a conductive member of the other base material.

6. A light emitting device comprising: the wiring board according to claim 1; and a light source disposed on the wiring board.

7. A step of preparing the wiring board according to claim 1; and arranging a light source on the wiring board.

Images