JP2023047219A - Connection structure of printed wiring board, light emission device, and manufacturing method of the same - Google Patents

Abstract

To provide a manufacturing method of a connection structure which can arrange a conductive member of the connection structure of a printed wiring board having the thin thickness at a proper position, a manufacturing method of a light emission device including the same, the connection structure of the printed wiring board having the thin thickness and the light emission device having the same.SOLUTION: A manufacturing method of a connection structure 50 comprises the steps of: preparing a first wiring board 51 having a first hole in a portion of a first wiring layer 121 and a second wiring board 52a having a second hole and a third hole in a portion of a second wiring layer 122 such that the first hole is arranged at a position sandwiched between the second hole and the third hole in the plan view when being superimposed; charging a conductive member to the first hole; superimposing the first wiring board 51 on the second wiring board 52a; and electrically connecting the first wiring layer 121 with the second wiring layer 122.SELECTED DRAWING: Figure 1B

Description

TECHNICAL FIELD The present disclosure relates to a connection structure and a light-emitting device of a printed wiring board, and manufacturing methods thereof.

2. Description of the Related Art Conventionally, a printed wiring board connection structure in which a pair of printed wiring boards are connected has been disclosed. For example, Patent Literature 1 discloses a printed wiring board connection structure and a connection method in which a pair of printed wiring boards are bonded together via an adhesive sheet.

JP 2007-221077 A

The present disclosure provides a method for manufacturing a connection structure capable of arranging a conductive member of a connection structure of a thin printed wiring board at an appropriate position, a method for manufacturing a light emitting device including the same, and a thin print. An object of the present invention is to provide a wiring board connection structure and a light emitting device including the same.

In a method for manufacturing a connection structure (hereinafter referred to as a connection structure as appropriate) for a printed wiring board according to an embodiment of the present disclosure, a first wiring layer is formed on one surface, and the thickness at the portion of the first wiring layer is a first wiring board having a first hole in the direction thereof; and a second wiring board having a second wiring layer formed on one surface thereof and having a second hole and a third hole in the thickness direction at a portion of the second wiring layer. filling the first hole with a conductive member so that the conductive member protrudes from the first hole; and the other surface of the first wiring board and the second wiring layer. stacking the first wiring board and the second wiring board so that they face each other; and heating and pressing the conductive member to form the first wiring layer and the second wiring layer in the first hole In the preparing step, when the first wiring board and the second wiring board are overlapped, in plan view, the first hole corresponds to the The first wiring board and the second wiring board are prepared so as to be arranged at positions sandwiched between the second hole and the third hole.

In a method for manufacturing a connection structure for a printed wiring board according to an embodiment of the present disclosure, a first wiring layer is formed on one surface, and a first wiring having a first hole in the thickness direction at a portion of the first wiring layer. a step of preparing a substrate and a second wiring substrate having a second wiring layer formed on one surface and having a second hole and a third hole in a thickness direction at a portion of the second wiring layer; stacking the first wiring board and the second wiring board so that the other surface of the wiring board and the second wiring layer face each other; applying a conductive member; heating and pressurizing the conductive member to fill the first hole with the conductive member; and connecting the first wiring layer and the second wiring layer to the first hole. In the preparing step, when the first wiring board and the second wiring board are superimposed, in a plan view, the first hole corresponds to the second wiring board. The first wiring board and the second wiring board are prepared so as to be arranged at positions sandwiched between the second hole and the third hole.

A method for manufacturing a light-emitting device according to an embodiment of the present disclosure includes a step of manufacturing a connection structure by the method for manufacturing a connection structure of a printed wiring board; a connecting region and a light emitting region, and placing a light emitting element in the light emitting region.

A printed wiring board connection structure according to an embodiment of the present disclosure includes a first wiring board having a first wiring layer formed on one surface and having a first hole in the thickness direction at a portion of the first wiring layer; A second wiring substrate having a second wiring layer formed on one surface facing the other surface of the first wiring substrate, and having a second hole and a third hole in the thickness direction at a portion of the second wiring layer. and a conductive member arranged in the first hole and electrically connecting the first wiring layer and the second wiring layer, wherein the first hole corresponds to the second hole in a plan view. and the third hole.

A light-emitting device according to an embodiment of the present disclosure includes a connection structure of the printed wiring board, a connection region and a light-emitting region for forming the connection structure on the second wiring board, and the light emission and a light-emitting element installed in the partial region.

According to the embodiments of the present disclosure, a method for manufacturing a connection structure capable of arranging a conductive member of a connection structure of a thin printed wiring board at an appropriate position, and a method for manufacturing a light emitting device including the same, In addition, a connection structure of a printed wiring board with a small thickness and a light emitting device including the same can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows typically an example of the light-emitting device which concerns on embodiment. FIG. 1B is a schematic cross-sectional view taken along line IB-IB of FIG. 1A; It is a top view which expands and shows an example of the connection structure which concerns on embodiment typically. FIG. 2 is an enlarged plan view schematically showing an example of the first wiring board of the connection structure according to the embodiment; FIG. 4 is an enlarged plan view schematically showing an example of a second wiring board of the connection structure according to the embodiment; FIG. 1C is a schematic cross-sectional view taken along line IIIA-IIIA of FIG. 1C; FIG. 1C is a schematic cross-sectional view taken along line IIIB-IIIB of FIG. 1C; It is sectional drawing which expands and shows a part of connection structure which concerns on embodiment typically. It is a flow chart which shows the 1st manufacturing method of the bonded structure concerning an embodiment. FIG. 4 is a cross-sectional view schematically showing the first wiring board on which the first wiring layer is formed in the wiring board preparation step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a second wiring board on which a second wiring layer is formed in a wiring board preparation step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing the first wiring board in which the first holes are formed in the wiring board preparation step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a second wiring board in which second holes and third holes are formed in a wiring board preparing step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing the first wiring board in which the first holes are filled with the conductive member in the conductive member filling step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing the second wiring board in the conductive member filling step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are superimposed in the superposing step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step of the first manufacturing method of the connected structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing the first wiring board on which the first wiring layer is formed in the wiring board preparation step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a second wiring board on which a second wiring layer is formed in a wiring board preparation step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing the first wiring board in which the first holes are formed in the wiring board preparation step of the first manufacturing method of the connection structure according to the embodiment; FIG. 10 is a cross-sectional view schematically showing a second wiring board in which second and third holes (not shown) are formed in the wiring board preparation step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing the first wiring board in which the first holes are filled with the conductive member in the conductive member filling step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing the second wiring board in the conductive member filling step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are superimposed in the superposing step of the first manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step of the first manufacturing method of the connected structure according to the embodiment; It is a flowchart which shows the 2nd manufacturing method of the connection structure which concerns on embodiment. FIG. 5 is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are superimposed in the superposing step of the second manufacturing method of the connection structure according to the embodiment; FIG. 10 is a cross-sectional view schematically showing a state in which a conductive member is applied to a portion of the first hole on the first wiring board in the conductive member applying step of the second manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step of the first manufacturing method of the connected structure according to the embodiment; FIG. 5 is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are superimposed in the superposing step of the second manufacturing method of the connection structure according to the embodiment; FIG. 10 is a cross-sectional view schematically showing a state in which a conductive member is applied to a portion of the first hole on the first wiring board in the conductive member applying step of the second manufacturing method of the connection structure according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step of the first manufacturing method of the connected structure according to the embodiment; 4 is a flow chart showing a method for manufacturing a light emitting device according to an embodiment; FIG. 4 is a cross-sectional view schematically showing a light guide plate prepared in a light guide plate and an intermediate preparation step of a method for manufacturing a light emitting device according to an embodiment; FIG. 4 is a cross-sectional view schematically showing an intermediate prepared in a preparation step of the method for manufacturing the light emitting device according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which the light guide plate and the intermediate are adhered in the adhesion step of the method for manufacturing the light emitting device according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a state in which a third wiring layer is formed in the wiring layer forming step of the method for manufacturing the light emitting device according to the embodiment; FIG. 8 is an enlarged plan view schematically showing an example of a connection structure according to Modification 1; FIG. 10 is an enlarged plan view schematically showing an example of a first wiring board of a connection structure according to Modification 1; FIG. 11 is an enlarged plan view schematically showing an example of a second wiring board of a connection structure according to Modification 1; FIG. 11 is a plan view schematically showing an enlarged example of a second wiring board of a connection structure according to Modification 2; FIG. 11 is a plan view schematically showing an enlarged example of a wiring layer removed portion of a second wiring board of a connection structure according to Modification 2; FIG. 20C is a schematic cross-sectional view taken along line XXC-XXC of FIG. 20B in the case of a connection structure; FIG. 11 is a plan view schematically showing an enlarged example of another form of the wiring layer removed portion; FIG. 11 is a plan view schematically showing an enlarged example of another form of the wiring layer removed portion;

Embodiments are described below with reference to the drawings. However, the embodiments shown below are intended to exemplify the printed wiring board connection structure, the light emitting device, and their manufacturing methods for embodying the technical idea of the present embodiment, and are limited to the following. isn't it. In addition, unless there is a specific description, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to limit the scope of the present invention, but are merely examples. It's nothing more than Note that the sizes and positional relationships of members shown in each drawing may be exaggerated or simplified for clarity of explanation.

<<Embodiment>>
1A is a plan view schematically showing an example of a light emitting device according to an embodiment; FIG. FIG. 1B is a schematic cross-sectional view taken along line IB-IB of FIG. 1A. FIG. 1C is an enlarged plan view schematically showing an example of the connection structure according to the embodiment. FIG. 2A is an enlarged plan view schematically showing an example of the first wiring board of the connection structure according to the embodiment. FIG. 2B is an enlarged plan view schematically showing an example of the second wiring board of the connection structure according to the embodiment; FIG. 3A is a schematic cross-sectional view taken along line IIIA-IIIA in FIG. 1C. FIG. 3B is a schematic cross-sectional view taken along line IIIB-IIIB in FIG. 1C. FIG. 3C is a cross-sectional view schematically showing an enlarged part of the connection structure according to the embodiment.

[Light emitting device]
The light-emitting device 100 includes a connection structure 50 and a light-emitting section 60 . The second wiring board 52 has a connection region R1 for forming the connection structure 50 and a light emitting region R2 for installing the light emitting element. In addition, in the present embodiment, the connection structure 50 is formed in the connection portion region R1, and the light emission portion 60 is formed in the light emission portion region R2.
In the second wiring board 52, a second wiring board 52a in the connection region R1 and a second wiring board 52b in the light emitting region R2 are integrally formed. The connection structure 50 is a structure in which the first wiring board 51 and the second wiring board 52a are connected in the connection region R1.
First, after explaining the connection structure 50, the outline of the light emitting device 100 will be explained.

[Connection structure]
The connection structure 50 is, for example, a structure in which a first wiring board 51 that is a connector and a second wiring board 52 of the light emitting device 100 are connected.

The connection structure 50 has a first wiring layer 121 formed on one surface and a first wiring substrate 51 having a first hole 131 in the thickness direction at the portion of the first wiring layer 121 , and the other side of the first wiring substrate 51 . a second wiring board 52a having a second wiring layer 122 formed on one side and having a second hole 132 and a third hole 133 in the thickness direction at a portion of the second wiring layer 122; and a conductive member 30 arranged in the first hole 131 and electrically connecting the first wiring layer 121 and the second wiring layer 122 , and the first hole 131 is arranged in the second hole 132 and the second wiring layer 122 in plan view. It is arranged at a position sandwiched by three holes 133 .

The first wiring layers 121 are provided at predetermined intervals along one direction of the first wiring substrate 51, and the second wiring layers 122 are provided at predetermined intervals along one direction of the second wiring substrate 52a. The wiring layer 121 has a first hole 131 , and the second wiring layer 122 has a second hole 132 and a third hole 133 .

The first wiring board 51 includes a first base material 111 and a first wiring layer 121 provided on one surface of the first base material 111 . The first wiring board 51 is formed with a first hole 131 in the thickness direction thereof through which the conductive member 30 is provided through the first base material 111 and the first wiring layer 121 . The first wiring board 51 can be either a rigid board or a flexible board depending on the configuration of the first base material 111 . However, at least one of the first wiring board 51 and the second wiring board 52 preferably has flexibility. For example, the first wiring board 51 can be a flexible board, and the second wiring board 52 can be a flexible board or a rigid board.

The first base material 111 is insulating, and is made of an insulating resin material such as phenol resin, epoxy resin, polyimide resin, polyethylene terephthalate, polyethylene naphthalate, silicone resin, polyphthalamide, or liquid crystal polymer. there is When a rigid substrate is used, for example, glass epoxy substrate (FR-4), glass composite substrate (SEM3), bismaleimide triazine resin (BT resin), paper epoxy, etc. can be used.

The thickness of the first base material 111 is preferably 50 μm or more and 1000 μm or less. If the thickness of the first base material 111 is 50 μm or more, the strength of the first base material 111 can be improved. Also, the amount of the conductive member 30 arranged in the first hole 131 can be increased, and the conductive member 30 can be easily compressed within the first hole 131 . On the other hand, if the thickness is 1000 μm or less, the first wiring board 51 can be thinned. The thickness of the first base material 111 is preferably 75 μm or more and 500 μm or less, more preferably 100 μm or more and 400 μm or less.

The first wiring layer 121 is formed on the surface of the first base material 111 . The first wiring layer 121 is formed so as to be wired in a desired shape. Specifically, the first wiring layers 121 are provided at predetermined intervals along one direction of the first wiring board 51 . In this embodiment, seven linear first wiring layers 121 extending in the front-rear direction are provided in parallel at predetermined intervals in the left-right direction.

A metal material can be used for the first wiring layer 121. For example, single metals such as Ag, Al, Ni, Rh, Au, Cu, Ti, Pt, Pd, Mo, Cr, W, and Zn, or these metals can be used. An alloy containing can be suitably used. When the conductive member 30 contains Sn, the metal material used for the first wiring layer 121 is a single metal such as Cu, Ag, Zn, etc., which has relatively good reactivity with Sn, or an alloy containing these metals. is more preferred. More preferably, the first wiring layer 121 uses a metal material containing Cu as its main component. The “main component” means that 70% by mass or more, preferably 80% by mass or more of the base material of the first wiring layer 121 contains Cu. Furthermore, it is desirable to use a rolled copper foil for the first wiring layer 121 . This is because flexibility can be increased.
The thickness of the first wiring layer 121 is preferably 12 μm or more and 70 μm or less. If the thickness of the first wiring layer 121 is 12 μm or more, it becomes easier to form the first wiring layer. In addition, the contact area of the conductive member 30 increases on the side surface of the first wiring layer 121 around the first hole 131, and the contact resistance decreases. Thereby, the current capacity flowing through the connection structure 50 can be increased. On the other hand, if the thickness is 70 μm or less, the thickness of the first wiring board 51 can be reduced. In addition, for example, the thickness of the first wiring layer 121 can be 0.25 times or more and 1.25 times or less the thickness of the first base material 111 .

The width W of each first wiring layer 121 is preferably 0.1 mm or more and 0.5 mm or less. If the width W is 0.1 mm or more, it becomes easier to form the first hole 131 . On the other hand, if the width W is 0.5 mm or less, it becomes easier to increase the number of the first wiring layers 121 and to form a complicated wiring pattern. This makes it easier to adapt to various designs.
Also, the distance D between adjacent first wiring layers 121 is preferably 0.05 mm or more and 0.5 mm or less. If the distance D is 0.05 mm or more, even when the conductive members 30 protrude from the first holes 131 in the left-right direction, contact between the conductive members 30 protruding from the adjacent first holes 131 is further suppressed. becomes easier. As a result, short-circuiting of the light-emitting device 100 can be further suppressed. On the other hand, if the distance D is 0.5 mm or less, it becomes easier to increase the number of first wiring layers 121 and to form a complicated wiring pattern. This makes it easier to adapt to various designs.

The first hole 131 is formed to penetrate the first wiring layer 121 and the first base material 111 . The first holes 131 are formed in the respective portions of the first wiring layer 121 so that their centers are on a straight line along the left-right direction of the first wiring board 51 . The first hole 131 is circular in plan view, and preferably has a diameter of 0.05 mm or more and 0.4 mm or less. If the diameter of the first hole 131 is 0.05 mm or more, it becomes easy to fill the conductive member 30 . On the other hand, if the diameter is 0.4 mm or less, it becomes easier to form the first hole 131 on the first wiring layer 121 .
Alignment holes 141 for aligning the first wiring board 51 and the second wiring board 52a when the first wiring board 51 and the second wiring board 52a are overlaid are provided at both ends in the left-right direction.

The second wiring board 52a is the second wiring board in the connection region R1 of the second wiring board 52. As shown in FIG. The second wiring board 52a is a portion protruding from one side of the rectangular light emitting region R2 in plan view. Here, two rectangular second wiring boards 52a are formed.

The second wiring board 52 a includes a second base material 112 and a second wiring layer 122 provided on one surface of the second base material 112 . The second wiring board 52a can be either a rigid board or a flexible board depending on the configuration of the second base material 112. FIG.
The material, thickness, etc. of the second base material 112 can be the materials, thickness, etc. exemplified for the first base material 111 . However, since the conductive member 30 is arranged in the first hole 131 of the first base material 111, the thickness of the first base material 111 is, for example, 1.01 times or more the thickness of the second base material 112 and 2.5 times. It can be doubled or less.

The second wiring layer 122 is formed on the surface of the second base material 112 . The second wiring layer 122 is formed so as to be wired in a desired shape. Specifically, the second wiring layers 122 are provided at predetermined intervals along one direction of the second wiring board 52a. In this embodiment, seven linear second wiring layers 122 extending in the front-rear direction are provided in parallel at predetermined intervals in the left-right direction. A part of each second wiring layer 122 is provided at a position overlapping with each first wiring layer 121 in plan view.
The material, thickness, width, and distance between the second wiring layers 122 and 122 of the second wiring layer 122 can be the materials, thicknesses, and the like exemplified for the first wiring layer 121 . However, since the conductive member 30 is arranged on the side surface of the first wiring layer 121 around the first hole 131, the thickness of the first wiring layer 121 is 0.25 times the thickness of the second wiring layer 122, for example. It can be more than 1.0 times and less than 1.0 times. Also, for example, the thickness of the second wiring layer 122 can be 0.1 times or more and 0.75 times or less of the thickness of the second base material 112 .

The second hole 132 and the third hole 133 are formed so as to penetrate the second wiring layer 122 and the second base material 112 . The second holes 132 are formed in the respective portions of the second wiring layer 122 so that their centers are on a straight line along the horizontal direction of the second wiring substrate 52a. The third hole 133 is formed in each portion of the second wiring layer 122 so that the center thereof is on a straight line along the horizontal direction of the second wiring board 52a. The second hole 132 and the third hole 133 are circular in plan view, and the diameter of the second hole 132 and the third hole 133 is preferably 0.05 mm or more and 0.4 mm or less. If the diameter of the second hole 132 and the third hole 133 is 0.05 mm or more, when the conductive member 30 protrudes from the first hole 131, the protruding conductive member 30 is replaced by the second hole 132 and the third hole. It becomes easy to escape from 133. This can further suppress the conductive member 30 from spreading beyond the second hole 132 and the third hole 133 . As a result, uniform pressure can be applied, stable connection can be achieved, and the probability of causing migration due to moisture absorption due to unnecessary extrusion of the resin can be reduced. On the other hand, if the diameter is 0.4 mm or less, it becomes easier to form the second hole 132 and the third hole 133 on the second wiring layer 122 .
Further, the second base material 112 is provided with alignment holes 142 at both ends in the left-right direction for alignment when the first wiring board 51 and the second wiring board 52a are overlapped.

The second wiring board 52 a is arranged such that the second wiring layer 122 faces the other surface of the first wiring board 51 . That is, the first wiring layer 121 and the second wiring layer 122 are arranged in the same direction with respect to the first base material 111 and the second base material 112 . As a result, in the step of connecting the first wiring layer 121 and the second wiring layer 122, the first wiring layer 121 and the second wiring layer 122 can be visually confirmed, so that the misalignment of the wiring can be easily confirmed. This facilitates connection between the first wiring layer 121 and the second wiring layer 122 .

Further, the first hole 131 is arranged at a position sandwiched between the second hole 132 and the third hole 133 in plan view. The fact that the first hole 131 is arranged at a position sandwiched between the second hole 132 and the third hole 133 means, for example, that the first hole 131 extends in the front-rear direction of the first wiring layer 121 and the second wiring layer 122 in plan view. It means that the holes are arranged so that at least a part of each of the first hole 131, the second hole 132, and the third hole 133 overlaps the imaginary straight line L1. In this embodiment, the centers of the first hole 131, the second hole 132, and the third hole 133 are arranged so as to overlap the imaginary straight line L1. In each hole, it is preferable that the smaller one of the areas divided into the left and right sides of the hole by the imaginary line L1 in plan view is 20% or more of the entire hole area, and 30% or more of the entire hole area. It is more preferable to have Furthermore, as in this embodiment, it is preferable that the virtual line L1 passes through the center of the hole and divides the area of the entire hole into 50% portions.

Since the first hole 131 is located between the second hole 132 and the third hole 133 , when the conductive member 30 protrudes from the first hole 131 , the protruding conductive member 30 can be removed. It can escape from the second hole 132 and the third hole 133 . This can further suppress the conductive member 30 from spreading beyond the second hole 132 and the third hole 133 . Therefore, insulation between the second wiring layers 122 can be ensured.

The distance between the center of the first hole 131 and the center of the second hole 132 is preferably 0.5 mm or more and 2 mm or less. If the distance between the center of the first hole 131 and the center of the second hole 132 is 0.5 mm or more, when the first wiring board 51 and the second wiring board 52a are overlapped, the first hole 131 and the second hole 131 are separated from each other. Since it becomes easy to secure the distance from 132, it becomes easy to form the second hole 132. Moreover, since it becomes easy to secure the distance between the second hole 132 and the third hole 133, it is possible to suppress the decrease in the strength of the second wiring board 52a. On the other hand, if the distance between the center of the first hole 131 and the center of the second hole 132 is 2 mm or less, when the conductive member 30 protrudes from the first hole 131, the protruding conductive member 30 is moved to the second hole. It becomes easy to escape from 132. This can further suppress the conductive member 30 from spreading beyond the second hole 132 and the third hole 133 . Therefore, insulation between the second wiring layers 122 can be ensured. For the same reason, the distance between the center of the first hole 131 and the center of the third hole 133 is preferably 0.5 mm or more and 2 mm or less. For the same reason, the shortest distance between the outer edge of the first hole 131 and the outer edge of the second hole 132 in plan view is preferably 0.2 mm or more and 1.9 mm or less, and more preferably 0.3 mm or more and 1.0 mm or less. is more preferable. The shortest distance between the outer edge of the first hole 131 and the outer edge of the third hole 133 is preferably 0.1 mm or more and 1.9 mm or less, more preferably 0.2 mm or more and 0.8 mm or less.

The conductive member 30 is arranged in the first hole 131 and electrically connects the first wiring layer 121 and the second wiring layer 122 . The conductive member 30 is compressed within the first hole 131 during manufacture, for example, by heating and pressurizing the conductive member 30 as described below. The first wiring layer 121 of the first wiring board 51 and the second wiring layer 122 of the second wiring board 52 are connected by the conductive member 30 through the first hole 131 . Since the first wiring layer 121 and the second wiring layer 122 are connected by the conductive member 30, it is not necessary to use an adhesive member such as an adhesive sheet for connecting the first wiring board 51 and the second wiring board 52a. do not have. Therefore, the thickness of the connection structure 50 can be reduced.

As the conductive member 30, for example, a mixture of flake-shaped, scale-shaped, or bark-shaped filler such as silver powder or copper powder and a thermosetting binder resin can be used. As the conductive member 30, it is preferable to use a melting point shift type conductive member containing Sn—Bi solder powder, Cu powder, and resin. By using such a conductive member 30, Cu contained in the first wiring layer 121 and the second wiring layer 122 and Sn contained in the conductive member 30 undergo a diffusion reaction, as will be described later. Here, the “melting point shift type” means that when the melting point of Cu as a single substance is 1085° C. and the melting point of Sn—Bi solder powder is 140° C., after performing a heat curing treatment, in the next heat treatment process, the conductive A material that has almost no melting point at 140°C. In other words, in the first heat treatment, the melting point of Sn—Bi solder is observed and the reactivity is high, and in the second heat treatment step, the melting point of Sn—Bi solder is not observed. Reliability can be improved. This allows a large current to flow.

The conductive member 30 may contain 40 parts by mass or more and 60 parts by mass or less of Sn—Bi solder powder and 20 parts by mass or more and 35 parts by mass or less of Cu powder per 100 parts by mass of the conductive member 30. preferable. By using such a conductive member 30, the diffusion reaction can be promoted more. Sn—Bi solder powder may contain Sn and Bi in appropriate composition ratios. Also, powders of Ag, Fe, Ni, Zn, Al, Ti, etc. may be added to adjust the coefficient of linear expansion of the conductive member 30 . In the Sn—Bi solder powder, the mass ratio of Sn:Bi is preferably 38:62 to 46:54, more preferably 41:59 to 43:57.

Examples of the resin contained in the conductive member 30 include epoxy resin, modified epoxy resin, glass epoxy resin, silicone resin, modified silicone resin, polyolefin resin, polycarbonate resin, polystyrene resin, acrylic resin, acrylate resin, and polymethyl methacrylate. Resins (PMMA, etc.), urethane resins, polyimide resins, polynorbornene resins, fluorine resins, and the like can be used.

In the connection structure 50, for example, the melting point shifting type conductive member 30 containing Sn—Bi solder powder, Cu powder, and resin is used. The wiring board 51 and the second wiring board 52 are heated. As a result, the connection structure 50 includes Cu contained in the first wiring layer 121 and the second wiring layer 122 and the conductive A Cu—Sn alloy is formed by a diffusion reaction with Sn contained in the conductive member 30 . As a result, the electrical connection between the conductive member 30 and the first wiring layer 121 and the second wiring layer 122 is improved, resulting in excellent reliability against thermal cycles and the like. In addition, the connection resistance value of the connection portion becomes low, so that a large current can flow. Therefore, it is possible to provide a light-emitting device suitable for mounting an LED or the like through which a large current continuously flows. It should be noted that the diffusion-reacted portion may form the diffusion-reacted layer 35 in layers.

As described above, in this embodiment, the first wiring board 51 and the second wiring board 52a are connected by the conductive member 30 without using an adhesive member such as an adhesive sheet. Therefore, the thickness of the connection structure 50 can be reduced. Further, by arranging the first hole 131 at a position sandwiched between the second hole 132 and the third hole 133 in plan view, the conductive member 30 can be arranged at an appropriate position of the connection structure 50. can.

[Overview of Light Emitting Device]
Next, the outline of the light emitting device will be described.
The light emitting device 100 has a connection structure 50 of a printed wiring board, a connection region R1 and a light emission region R2 for forming the connection structure 50 on a second wiring board 52, and is installed in the light emission region R2. and a light-emitting element 2 .
The light emitting device 100 includes a light guide plate 6 installed facing the second wiring board 52b, a light reflection member 7 installed between the light guide plate 6 and the light emitting region R2, and an opening of the light reflection member 7. and a light-emitting element 2 disposed in the light-emitting region R2 with the light extraction surface side facing the light guide plate 6 via the light guide plate 6 .
Specifically, the light emitting device 100 is a surface emitting light source including at least a first wiring board 51, a second wiring board 52b, a light emitting element 2, a light guide plate 6, and a light reflecting member 7. .
The outline of the light emitting device 100 will be described below.

In the light-emitting device 100, a plurality of light-emitting modules 10 can be arranged on the second wiring board 52b in a rectangular or square shape of, for example, 2 to 200 columns×2 to 200 rows. The light-emitting module 10 is configured by aligning a plurality of light-emitting structures 1 in a rectangle or square of, for example, 2 to 200 columns×2 to 200 rows.

(First wiring board)
The first wiring board 51 is as described above.

(Second wiring board)
The second wiring board 52b aligns the plurality of light emitting modules 10 in the light emitting region R2 and supplies current to the light emitting modules 10 from the outside. The second wiring board 52b includes a second base material 112, a second wiring layer 122 formed on one surface of the second base material 112, and a surface opposite to the one surface on which the second wiring layer 122 is formed. and a third wiring layer 123 formed on the other surface of the substrate. The second wiring board 52 b includes a pair of wiring pads 18 continuous to the third wiring layer 123 formed on the second base material 112 for each light emitting module 10 . At least two (four in FIG. 1B) via holes 181 are formed in each of the pair of wiring pads 18 . Further, the second wiring board 52b is provided with the second wiring layer 122 on one surface side, and the plurality of light emitting modules 10 are arranged on the second wiring layer 122. As shown in FIG. Further, the second wiring board 52b has openings for exposing the wiring pads 18 on the other surface side, and a covering layer 19 covering the second base material 112 is provided.
The second wiring board 52b in the light emitting region R2 and the second wiring board 52a in the connection region R1 are integrated with the second base material 112, and the second wiring layer 122 is printed.

The same metal material as the first wiring layer 121 can be used for the third wiring layer 123 and the wiring pads 18 . The coating layer 19 can be formed using polyimide resin, phenylsilicone resin, dimethylsilicone resin, or the like.
The light emitting device 100 includes a conductive member 31 filled across the two via holes 181, and a protective member 40 provided to cover the conductive member 31 from one surface side of the second wiring board 52b. is preferred. As the conductive member 31, the same material as the conductive member 30 of the connection structure 50 can be used. As the protective member 40, the same material as the covering layer 19 can be used.

(light-emitting structure)
The light emitting structure 1 preferably includes, for example, a light source 11 , a light guide plate 6 and a light reflecting member 7 . The light source 11 includes the light emitting element 2, the translucent member 3 provided on the light extraction surface of the light emitting element 2, the light diffusion layer 4 provided on the upper surface of the translucent member 3, and the side surface of the light emitting element 2. and a covering member 5 . The upper surface of the light-transmitting member 3 is a surface that faces the light guide plate 6 . The light reflecting member 7 is provided on the side surface of the covering member 5 , and the light guide plate 6 is provided on the light reflecting member 7 and the light diffusion layer 4 .

For example, a known semiconductor light-emitting element can be used as the light-emitting element 2 , and a light-emitting diode is exemplified as the light-emitting element 2 . The light-emitting element 2 may use a light source that emits blue light, or use a light-emitting element that emits a plurality of different colored lights, and may emit white light by mixing red, blue, and green colored lights, for example. . As the light-emitting element 2, an element that emits light of any wavelength can be selected, and the composition, emission color, size, number, etc. of the light-emitting element to be used can be appropriately selected according to the purpose. . For example, as a device for emitting blue and green light, a light-emitting device using a nitride semiconductor (In _x Al _y Ga _1-x-y N, 0≦X, 0≦Y, X+Y≦1) or GaP is used. can be used. A light-emitting element containing a semiconductor such as GaAlAs, AlInGaP, or the like can be used as the element that emits red light. Semiconductor light-emitting elements made of materials other than those described above can also be used, and the emission wavelength can be variously selected depending on the material of the semiconductor layer and its crystallinity.

The translucent member 3 is a member that adjusts the color of light emitted from the light emitting element 2 . The translucent member 3 includes a translucent material and a phosphor that converts the wavelength of light. The translucent material is preferably a material having a higher refractive index than the material of the light guide plate 6 . As the translucent material, for example, an epoxy resin, a silicone resin, a modified epoxy resin, a modified silicone resin, a resin obtained by mixing these resins, glass, or the like can be used. However, from the viewpoint of light resistance and moldability, it is preferable to select a silicone resin or a modified epoxy resin.

Examples of phosphors include oxides and oxynitrides such as YAG phosphors, LAG phosphors, chlorosilicate phosphors, β-sialon phosphors, CASN phosphors, SCASN phosphors, KSF phosphors, and KSAF phosphors. materials, nitrides, fluoride-based phosphors, and the like can be used. Also, the translucent member 3 can contain quantum dots.
The light diffusion layer 4 is a member that diffuses the light from the light emitting element 2 , and is a member that diffuses the light transmitted through the translucent member 3 here. The light diffusing layer 4 is formed by adding a light diffusing material such as titanium oxide, aluminum oxide, silicon oxide, zinc oxide, etc. to the base material of the translucent material described above in a dispersed state.

The covering member 5 is a member that protects the light emitting element 2 and reflects light from the side surface of the light emitting element 2 to return the light to the light extraction surface side. The covering member 5 is provided on the side surface and/or the bottom surface of the light emitting element 2 to cover the light emitting element 2 . By providing the covering member 5 , the light emitted from the light emitting element 2 can be efficiently introduced into the light guide plate 6 . In addition, since the covering member 5 serves both as a member that protects the light emitting element 2 and as a reflecting member that is provided on the surface of the light guide plate 6 opposite to the emission surface, the luminous flux of the light emitting device 100 can be improved. The light-reflecting material of the covering member 5 is preferably a resin containing a white pigment or the like. In order to reduce the cost of the light emitting device 100, the coating member 5 is preferably made of silicone resin containing inexpensive titanium oxide.

The light guide plate 6 is a translucent member that receives light from the light source 11 and emits planar light. The light guide plate 6 may have a concave portion 6 a for installing the light emitting element 2 at a position on the lower surface side facing the upper surface of the light diffusion layer 4 . Here, the light guide plate 6 has a concave portion 6a for housing the translucent member 3 and the light diffusing layer 4 on the second main surface opposite to the first main surface that serves as the light emitting surface.

Materials for the light guide plate 6 include thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, and polyester, resin materials such as thermosetting resins such as epoxy resins and silicone resins, and translucent materials such as glass. can be used. In particular, a thermoplastic resin material is preferable because it can be efficiently manufactured by injection molding, and polycarbonate, which has high translucency and is inexpensive, is more preferable. The light guide plate 6 can be molded by injection molding or transfer molding, for example.

It is preferable that the light guide plate 6 has a flat upper surface and a flat lower surface other than the concave portion 6a. That is, the light guide plate 6 is formed in a flat plate shape except for the concave portion 6a. In addition, the light emitting element 2 is arranged to face the concave portion 6a of the light guide plate 6, and the translucent member 3 and the light diffusion layer 4 are housed therein. Manufacture of the light-emitting device 100 becomes easy by making the light-guide plate 6 into such a structure. However, unevenness or a lens shape such as a Fresnel lens may be formed on the upper surface side and/or the lower surface side of the light guide plate 6 . This is because the light toward the upper surface of the light guide plate 6 can be made uniform.

The light reflecting member 7 is a member that reflects light from the side surface of the light emitting element 2 and returns the light to the light extraction surface side. The light reflecting member 7 is arranged on the second wiring layer 122 of the second wiring board 52b and arranged around the covering member 5 . The light reflecting member 7 is preferably made of a light reflecting material similar to that of the covering member 5 . Also, the covering member 5 and the light reflecting member 7 may be made of the same light reflecting material without being partitioned.

In the light emitting structure 1, the light emitting element 2 and the translucent member 3 are adhered with a translucent adhesive member. The light diffusing layer 4 may be formed by applying a translucent material containing a light diffusing agent onto the translucent member 3 . In the light-emitting structure 1, the light guide plate 6, the translucent member 3, and the light diffusion layer 4 can be joined by a joining member. In this case, the translucent member 3 to which the light emitting element 2 is adhered and the light diffusion layer 4 are arranged in the recess 6a of the light guide plate 6, and the wall surface of the recess 6a and the side surfaces of the translucent member 3 and the light diffusion layer 4 are arranged. It is preferable to provide a joining member between. Alternatively, the light diffusion layer 4 may be formed by placing a member forming the light diffusion layer 4 in the concave portion 6a of the light guide plate 6 and contacting or adhering it to the light emitting element 2 having the translucent member 3 . At this time, the light diffusion layer 4 having a predetermined thickness may be formed in advance. Furthermore, the light guide plate 6 and the light reflecting member 7 can be joined with a joining member. Note that known adhesives such as epoxy resins and silicone resins can be used for the translucent adhesive member and the bonding member.

In the light emitting module 10 , the second wiring layer 122 is formed on the surface of the electrode of the light emitting element 2 , the covering member 5 and the light reflecting member 7 . In the light emitting device 100 , the second wiring layer 122 and the conductive member 31 provided inside the via hole 181 are connected to electrically connect the light emitting elements 2 of the plurality of light emitting structures 1 . Thus, the light emitting section 60 of the light emitting device 100 is configured.

[Method for manufacturing connection structure]
<First manufacturing method>
Next, an example of the first manufacturing method of the connection structure according to the embodiment will be described.
FIG. 4 is a flow chart showing a first manufacturing method of the connection structure according to the embodiment. 5A to 8B are schematic cross-sectional views corresponding to line IIIA-IIIA of FIG. 1C in each step of the first manufacturing method of the connection structure according to the embodiment.

FIG. 5A is a cross-sectional view schematically showing the first wiring board on which the first wiring layer is formed in the wiring board preparation step. FIG. 5B is a cross-sectional view schematically showing the second wiring board on which the second wiring layer is formed in the wiring board preparation step. FIG. 6A is a cross-sectional view schematically showing the first wiring board in which the first hole is formed in the wiring board preparation step. FIG. 6B is a cross-sectional view schematically showing the second wiring board in which the second hole and the third hole are formed in the wiring board preparation step. FIG. 7A is a cross-sectional view schematically showing the first wiring board in which the conductive member is filled in the first hole in the conductive member filling step. FIG. 7B is a cross-sectional view schematically showing the second wiring board in the conductive member filling step. FIG. 8A is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are overlaid in the superposing step. FIG. 8B is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step.

9A to 12B are schematic cross-sectional views corresponding to line IIIB-IIIB in FIG. 1C in each step of the first manufacturing method of the connection structure according to the embodiment.
FIG. 9A is a cross-sectional view schematically showing the first wiring board on which the first wiring layer is formed in the wiring board preparation step. FIG. 9B is a cross-sectional view schematically showing the second wiring board on which the second wiring layer is formed in the wiring board preparation step. FIG. 10A is a cross-sectional view schematically showing the first wiring board in which the first hole is formed in the wiring board preparation step. FIG. 10B is a cross-sectional view schematically showing a second wiring board in which a second hole and a third hole (not shown) are formed in the wiring board preparation step. Since FIG. 10B is a schematic cross-sectional view corresponding to line IIIB-IIIB in FIG. 1C, the second and third holes are not shown. FIG. 11A is a cross-sectional view schematically showing the first wiring board in which the conductive member is filled in the first hole in the conductive member filling step. FIG. 11B is a cross-sectional view schematically showing the second wiring board in the conductive member filling step. FIG. 12A is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are overlaid in the superposing step. 12B is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step; FIG.

The manufacturing method of the connection structure 50 includes a first wiring board 51 having a first wiring layer 121 formed on one surface and a first hole 131 in the thickness direction at a portion of the first wiring layer 121; a step of preparing a second wiring board 52a having a second wiring layer 122 formed thereon and having a second hole 132 and a third hole 133 in the thickness direction at the portion of the second wiring layer 122; a step of filling the first hole 131 with the conductive member 30 so as to protrude from the first hole 131; and a step of heating and pressurizing the conductive member 30 to electrically connect the first wiring layer 121 and the second wiring layer 122 through the first hole 131. In the preparing step, when the first wiring board 51 and the second wiring board 52a are overlapped, the first hole 131 is sandwiched between the second hole 132 and the third hole 133 in plan view. A first wiring board 51 and a second wiring board 52a are prepared so as to be arranged at positions.

Specifically, the manufacturing method of the connection structure 50 includes a wiring board preparation step S101, a conductive member filling step S102, an overlapping step S103, and a connection step S104. In addition to these steps, a diffusion reaction step S105 may be included.
Note that the material, arrangement, etc. of each member are as described in the explanation of the connection structure 50, so the explanation is omitted here as appropriate.

(Wiring board preparation process)
The wiring board preparing step S101 is a step of preparing a first wiring board 51 having a first hole 131 and a second wiring board 52a having a second hole 132 and a third hole 133. FIG.

In this step S101, first wiring layers 121 are provided at predetermined intervals along one direction of the first wiring substrate 51, and a first wiring substrate having first holes 131 in respective portions of the first wiring layers 121; A second wiring board 52a having second wiring layers 122 provided at predetermined intervals along one direction of the second wiring board 52a, and having a second hole 132 and a third hole 133 in each part of the second wiring layers 122; , to prepare.

In this step S101, as preparation of the first wiring board 51, for example, first, a commercially available single-sided copper-clad laminate having a copper foil adhered to one side is prepared. Next, the copper foil is etched and patterned to form the first wiring layer 121 . Instead of using a commercially available single-sided copper clad laminate, the first wiring layer 121 may be formed by bonding a copper foil to the surface of the first base material 111 and etching or the like. Alternatively, a single-sided copper-clad laminate on which the first wiring layer 121 is formed in advance may be purchased.
Next, a first hole 131 is formed in the first wiring layer 121 from the surface side of the first base material 111 by drilling, punching, or laser processing, for example. At this time, the positioning holes 141 are similarly formed at both ends of the first base material 111 in the left-right direction.

In this step S101, as preparation of the second wiring board 52a, the second wiring board 52a having the second holes 132 and the third holes 133 formed in the same manner as the first wiring board 51 is prepared. Also, positioning holes 142 are formed at both ends of the second base material 112 in the left-right direction.
The first hole 131, the second hole 132, the third hole 133, and the alignment holes 141 and 142 are formed in the first and second positions when the first wiring board 51 and the second wiring board 52a are superimposed on each other in plan view. The forming position is adjusted so that the first hole 131 is located between the second hole 132 and the third hole 133 .

(Conductive member filling step)
The conductive member filling step S<b>102 is a step of filling the first hole 131 with the conductive member 30 so that the conductive member 30 protrudes from the first hole 131 .
In this step S102, for example, the conductive member 30 is filled into the first holes 131 from the surface of the first wiring board 51 through a mask by screen printing. Then, by removing the mask, the conductive member 30 protrudes from the first hole 131 by the thickness of the mask to form a projecting portion 30a.

(Superposition process)
The stacking step S103 is a step of stacking the first wiring substrate 51 and the second wiring substrate 52a so that the other surface of the first wiring substrate 51 and the second wiring layer 122 face each other.
In this step S103, alignment is performed so that the first wiring board 51 and the second wiring board 52a are arranged as desired. Alignment is performed by inserting alignment pins 90 into alignment holes 141 and 142 provided in the first wiring board 51 and the second wiring board 52a.
In this step S103, the first wiring board 51 and the second wiring board 52a are arranged such that the first wiring layer 121 of the first wiring board 51 and the second wiring layer 122 of the second wiring board 52a both face upward, Alignment pins 90 are inserted into the respective alignment holes 141 and 142 . Then, the first wiring board 51 and the second wiring board 52a are overlapped so that the first hole 131 is positioned between the second hole 132 and the third hole 133 in plan view.

(Connection process)
The connection step S<b>104 is a step of electrically connecting the first wiring layer 121 and the second wiring layer 122 .
In this step S104, for example, the protruding portion 30a protruding from the first hole 131 is heated and pressurized via the release paper 80. As shown in FIG. By this pressurizing process, the conductive member 30 filled in the first hole 131 is compressed. Thereby, the first wiring layer 121 and the second wiring layer 122 are electrically connected by the conductive member 30 . Further, by heating and pressurizing the projecting portion 30a, the upper surface of the conductive member 30 becomes flat. Thereby, the appearance of the connection structure 50 is improved. Further, for example, if the top surface of the conductive member 30 is uneven, there is a risk that the conductive member 30 may be damaged when an object hits the convex portion. , such damage to the conductive member 30 can be prevented.

In this step S104, the heating temperature is preferably 60° C. or higher and 130° C. or lower. If the heating temperature is 60° C. or higher, the conductive member 30 becomes soft and the conductive member 30 can be easily pressed. On the other hand, if the heating temperature is 130° C. or less, the energy for heating can be reduced, which is economical. Moreover, the pressure at the time of pressurization can be, for example, 1 MPa or more and 6 MPa or less.

(Diffusion reaction process)
In the diffusion reaction step S105, the first wiring substrate 51 and the second wiring substrate 52a with the conductive members 30 filled in the first holes 131 are heat-treated to remove Cu contained in the first wiring layer 121 and the second wiring layer 122. and Sn contained in the conductive member 30 are subjected to a diffusion reaction to form an alloy.

In this step S105, the heat treatment temperature is preferably 180° C. or higher and 280° C. or lower. If the heat treatment temperature is 180° C. or higher, the diffusion reaction is likely to be promoted. On the other hand, if the heat treatment temperature is 280° C. or less, the load on the first wiring board 51 and the second wiring board 52a can be reduced. Note that the heat treatment time can be, for example, 3 minutes or more and 60 minutes or less. In this step S105, the heat treatment is preferably performed in a nitrogen atmosphere. By performing the heat treatment in a nitrogen atmosphere, the diffusion reaction is facilitated.
In addition, the diffusion reaction step may be performed as necessary, and may be omitted.

<Second manufacturing method>
Next, an example of a second method for manufacturing the connection structure according to the embodiment will be described.
FIG. 13 is a flow chart showing a second manufacturing method of the connection structure according to the embodiment. 14A to 14C are schematic cross-sectional views corresponding to line IIIA-IIIA in FIG. 1C in each step of the second manufacturing method of the connection structure according to the embodiment.

FIG. 14A is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are overlaid in the superposing step. FIG. 14B is a cross-sectional view schematically showing a state in which the conductive member is applied to the portion of the first hole on the first wiring board in the conductive member applying step. FIG. 14C is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step.

15A to 15C are schematic cross-sectional views corresponding to line IIIB-IIIB in FIG. 1C in each step of the second manufacturing method of the connection structure according to the embodiment.
FIG. 15A is a cross-sectional view schematically showing a state in which the first wiring board and the second wiring board are overlaid in the superposing step. FIG. 15B is a cross-sectional view schematically showing a state in which the conductive member is applied to the portion of the first hole on the first wiring board in the conductive member applying step. FIG. 15C is a cross-sectional view schematically showing a state in which the conductive member is heated and pressurized in the connecting step.

The manufacturing method of the connection structure 50 includes a first wiring board 51 having a first wiring layer 121 formed on one surface and a first hole 131 in the thickness direction at a portion of the first wiring layer 121; preparing a second wiring board 52a having a second wiring layer 122 formed thereon and having a second hole 132 and a third hole 133 in the thickness direction at a portion of the second wiring layer 122; stacking the first wiring board 51 and the second wiring board 52a so that the other surface and the second wiring layer 122 face each other; 30, heating and pressurizing the conductive member 30 to fill the first hole 131 with the conductive member 30, and connecting the first wiring layer 121 and the second wiring layer 122 through the first hole 131. In the preparing step, when the first wiring board 51 and the second wiring board 52a are overlapped, the first hole 131 and the second hole 132 are seen in plan view. The first wiring board 51 and the second wiring board 52a are prepared so as to be arranged at a position sandwiched between the second wiring board 51 and the third hole 133.

Specifically, the manufacturing method of the connection structure 50 includes a wiring board preparation step S201, a superposition step S202, a conductive member application step S203, and a connection step S204. In addition to these steps, a diffusion reaction step S205 may be included.
Note that the material, arrangement, etc. of each member are as described in the explanation of the connection structure 50, so the explanation is omitted here as appropriate.

(Wiring board preparation process)
The wiring board preparing step S201 is the same as the wiring board preparing step S101 described in the first manufacturing method, and thus description thereof is omitted here.

(Superposition process)
The overlaying step S202 is the same as the overlaying step S103 described in the first manufacturing method, so the description is omitted here.

(Conductive member application step)
The conductive member applying step S203 is a step of applying the conductive member 30 to the portion of the first hole 131 on the first wiring board 51 .
In this step S203, the conductive member 30 is applied to the portion of the first hole 131 by potting, for example. The coating amount of the conductive member 30 is adjusted so that the first holes 131 are all filled and the first wiring layer 121 and the second wiring layer 122 are connected by the conductive member 30 .

(Connection process)
The connection step S<b>204 is a step of electrically connecting the first wiring layer 121 and the second wiring layer 122 .
In this step S<b>204 , for example, the first holes 131 are filled with the conductive member 30 by heating and pressurizing the conductive member 30 via the release paper 80 . By this pressurizing process, the first hole 131 is filled with the conductive member 30 and the conductive member 30 filled in the first hole 131 is compressed. Thereby, the first wiring layer 121 and the second wiring layer 122 are electrically connected by the conductive member 30 . Further, by heating and pressurizing the conductive member 30 applied to the portion of the first hole 131, the upper surface of the conductive member 30 is flattened.

In this step S204, the heating temperature is preferably 60° C. or higher and 130° C. or lower. If the heating temperature is 60° C. or higher, the conductive member 30 becomes soft and the conductive member 30 can be easily pressed. On the other hand, if the heating temperature is 130° C. or less, the energy for heating can be reduced, which is economical. Moreover, the pressure at the time of pressurization can be, for example, 1 MPa or more and 6 MPa or less.

(Diffusion reaction process)
The diffusion reaction step S205 is the same as the diffusion reaction step S105 described in the first manufacturing method, so the description is omitted here. In addition, the diffusion reaction step may be performed as necessary, and may be omitted.

[Method for manufacturing light-emitting device]
Next, an example of a method for manufacturing the light emitting device according to the embodiment will be described.
FIG. 16 is a flow chart showing a method for manufacturing a light emitting device according to the embodiment. 17A is a cross-sectional view schematically showing a light guide plate prepared in a light guide plate and intermediate preparation step of the method for manufacturing a light emitting device according to the embodiment; FIG. 17B is a cross-sectional view schematically showing an intermediate prepared in a preparatory step of the method for manufacturing the light emitting device according to the embodiment; FIG. 17C is a cross-sectional view schematically showing a state in which the light guide plate and the intermediate are adhered in the adhesion step of the method for manufacturing the light emitting device according to the embodiment; FIG. 17D is a cross-sectional view schematically showing a state in which a third wiring layer is formed in the wiring layer forming step of the method for manufacturing the light emitting device according to the embodiment; FIG.

The manufacturing method of the light-emitting device 100 includes a step of manufacturing the connection structure 50 by the manufacturing method of the connection structure 50 of the printed wiring board, and a connection portion region for forming the connection structure 50 in the second wiring board 52 . and a step of having R1 and a light emitting region R2 and installing the light emitting element 2 in the light emitting region R2.
In the method of manufacturing the light emitting device 100, the light guide plate 6 is prepared, and the light emitting element 2 emits light from the surface opposite to the light extraction surface through the opening of the light reflecting member 7 installed in the light emitting region R2. a step of preparing an intermediate body 13 placed in the light emitting region R2 so as to face the light emitting region R2; and

Specifically, the method for manufacturing the light emitting device 100 includes a connection structure manufacturing step S11, a light guide plate and intermediate body preparation step S12, an adhesion step S13, and a wiring layer forming step S14.
Note that the material, arrangement, etc. of each member are the same as those described in the description of the light emitting device 100 described above, so description thereof will be omitted as appropriate.

(Connection structure manufacturing process)
The connection structure manufacturing step S11 is a step of manufacturing the connection structure 50 by the method for manufacturing the connection structure 50 described above.
In this step S11, the connection structure 50 is manufactured by performing the above-described steps S101 to S105 or the above-described steps S201 to S205.

(Light guide plate and intermediate preparation step)
The light guide plate and intermediate body preparation step S12 is a step of preparing the light guide plate 6 and the intermediate body 13 . Note that this step S12 includes a step of installing the light emitting element 2 in the light emitting region R2.

In this step S12, the light guide plate 6 having the concave portions 6a is prepared. Moreover, in this step S12, the light source 11 including the light emitting element 2, the translucent member 3, the light diffusion layer 4, and the covering member 5 is prepared. Then, the light source 11 is arranged on the second wiring layer 122 in the light emitting region R2. The second wiring layer 122 in the light emitting region R2 can be formed at the same time as the second wiring layer 122 is formed in the connection region R1 in the wiring board preparation step S101 or the wiring board preparation step S201. can. After that, the light reflecting member 7 is provided so as to cover the second wiring layer 122 . Alternatively, after providing the second wiring layer 122, the light reflecting member 7 is provided so as to cover the second wiring layer 122, an opening is formed in the light reflecting member 7, and the light source 11 is connected to the second wiring layer 122 through the opening. to place. Thus, the intermediate 13 including the second base material 112, the second wiring layer 122, the light reflecting member 7, and the light source 11 is prepared.

(Adhesion process)
The bonding step S<b>13 is a step of bonding the light guide plate 6 to the intermediate body 13 .
In this step S13, the light source 11 is arranged in the recess 6a of the light guide plate 6, and the wall surface of the recess 6a and the side surfaces of the translucent member 3 and the light diffusion layer 4 are joined with a joining member. Alternatively, the light guide plate 6 and the light reflecting member 7 are joined with a joining member. As a result, the light emitting module 10 is formed on the second wiring layer 122 in the light emitting region R2.

(Wiring layer forming step)
The wiring layer forming step S<b>14 is a step of forming the third wiring layer 123 on the second base material 112 .
In this step S14, the third wiring layer 123 and the wiring pads 18 are formed on the other surface side of the second base material 112, and the covering layer 19 having openings exposing the third wiring layer 123 and the wiring pads 18 forms the third wiring layer. 2 covers the substrate 112; Thereby, the second wiring board 52b is formed.
In this step S14, conductive portions are formed to electrically connect the plurality of light emitting modules 10 and the second wiring board 52b. At this time, in this step S14, at least two via holes 181 formed for each pair of wiring pads 18, a conductive member 31 filled across the two via holes 181, and the conductive member 31 are provided as conductive portions. and a protective member 40 provided to cover from the side.

Although the embodiments for carrying out the invention have been specifically described above, the gist of the invention is not limited to these descriptions, and should be broadly interpreted based on the description of the scope of claims. In addition, various changes and modifications based on these descriptions are also included in the gist of the present invention.

<<Modification>>
[Modification 1]
FIG. 18 is an enlarged plan view schematically showing an example of a connection structure according to Modification 1. FIG. 19A is an enlarged plan view schematically showing an example of a first wiring board of a connection structure according to Modification 1. FIG. 19B is an enlarged plan view schematically showing an example of the second wiring board of the connection structure according to Modification 1. FIG.

In the connection structure 50A, in plan view, the first holes 131 are alternately provided on the left and right sides of the imaginary straight line L2 extending in one direction for each first wiring layer 121A. That is, the first holes 131 of the first wiring board 51A are provided alternately in the front-rear direction across the imaginary straight line L2 extending in the left-right direction of the first wiring board 51A. Further, the second hole 132 and the third hole 133 are arranged at positions sandwiching the first hole 131 in plan view. That is, the second holes 132 of the second wiring board 52aA are provided alternately in the front-rear direction for each of the second wiring layers 122A across the imaginary straight line L3 extending in the left-right direction of the second wiring board 52aA. Further, the third holes 133 of the second wiring board 52aA are provided alternately in the front-rear direction across the imaginary straight line L4 extending in the left-right direction of the second wiring board 52aA. Other matters are the same as those of the connection structure 50 in the embodiment. According to such a configuration, even when the conductive members 30 protrude from the first holes 131 in the horizontal direction on the second wiring board 52aA, the conductive members 30 protruding from the adjacent first holes 131 are in contact with each other. It becomes easier to suppress things. As a result, short-circuiting of the light-emitting device can be further suppressed.

In the method of manufacturing the connection structure 50A, in the wiring board preparation step, when the first wiring board 51A and the second wiring board 52aA are superimposed, the first hole 131 is formed as a virtual straight line extending in one direction in plan view. The first wiring substrates 51 and the second wiring substrates 52aA are prepared so that the first wiring layers 121 are arranged alternately on the left and right sides of L2. Other matters are the same as those of the manufacturing method of the connection structure 50 in the embodiment.

[Modification 2]
20A is an enlarged plan view schematically showing an example of a second wiring board of a connection structure according to Modification 2. FIG. 20B is an enlarged plan view schematically showing an example of the wiring layer removed portion of the second wiring board of the connection structure according to Modification 2. FIG. FIG. 20C is a schematic cross-sectional view along line XXC-XXC of FIG. 20B in the case of a connection structure. FIG. 21A is a plan view schematically showing an enlarged example of another form of the wiring layer removed portion. FIG. 21B is a plan view schematically showing an enlarged example of another form of the wiring layer removed portion. Note that FIG. 20B shows an enlarged example of the wiring layer removed portion of the second wiring board, and FIG. 20C shows a part of the cross section of the connection structure. 20B is a schematic cross-sectional view taken along line XXC-XXC of FIG. 20B.

The connection structure 50B has a wiring layer removed portion 151 obtained by removing a part of the second wiring layer 122B at a portion of the second wiring board 52aB facing the first hole 131 in plan view. The wiring layer removed portion 151 is a portion where the second base material 112 is exposed from the second wiring layer 122B. The wiring layer removed portion 151 is circular, and in the portion A facing the first hole 131, there is one in the center, one diagonally forward left, one diagonally forward right, one diagonally rear left, and one diagonally rear right. , a total of five are formed. A diffusion reaction layer 35 is formed on the side surface of the second wiring layer 122</b>B around the wiring layer removed portion 151 . Since the second wiring board 52aB has the wiring layer removed portion 151, the contact area of the conductive member 30 increases and the contact resistance decreases. Thereby, the current capacity flowing through the connection structure 50B can be increased. The wiring layer removed portion 151 can be formed, for example, by etching the second wiring layer.

The shape of the wiring layer removed portion is not limited to the shape of the wiring layer removed portion 151 described above, and may be another shape. For example, the wiring layer removal portion 151A is removed in the front-rear direction so that the second wiring layer 122C after removal extends longitudinally in the front-rear direction at a predetermined interval in the left-right direction. It is In addition, the wiring layer removal portion 151B is arranged such that the second wiring layer 122D after removal is positioned in the region A facing the first hole 131 in the left-right direction, the front-rear direction, the direction from the left oblique front to the right oblique rear, and the right oblique direction. It is removed in a fan shape so as to extend in a long direction from the front to the left and diagonally behind.

Further, although the first hole 131, the second hole 132, and the third hole 133 are circular in plan view, they may be rectangular, square, rhombus, or other quadrilaterals, triangles, or other shapes. There may be. Also, the number of first holes 131 sandwiched between the second hole 132 and the third hole 133 may be two or more. Further, the first hole 131, the second hole 132, and the third hole 133 are arranged side by side in the front-rear direction with reference to the imaginary straight line L1 extending in the front-rear direction in plan view, but they extend in the left-right direction. They may be arranged in the horizontal direction with reference to the virtual straight line, or they may be arranged with reference to the virtual straight line extending in other directions.

Further, the second wiring board 52a in the connection region R1 may have the coating layer 19 provided on the other surface thereof so as to be continuous with the coating layer 19 in the light emitting region R2. Also, the first wiring board 51 and the second wiring board 52a may be provided with a coating layer on one surface thereof, for example, at a portion where the first wiring board 51 and the second wiring board 52a do not overlap in plan view. As the material of the covering layer, the same material as that of the covering layer 19 can be used.
Moreover, although the light-reflecting member 7 is used in the light-emitting device 100, a light-transmitting member may be used instead of the light-reflecting member 7. FIG. As a material for the light-transmitting member, the same light-transmitting material as that used for the light-transmitting member 3 can be used.
In addition, the width of the second wiring layer 122 is made narrower than the width of the first wiring layer 121 to increase the number of the second wiring layers 122, so that the first wiring layers 121 and the first wiring layers 121 adjacent to each other are separated from each other in plan view. A second wiring layer 122 (hereinafter referred to as a gap wiring layer) may be arranged between them. As a result, the back wiring layer connected to the gap wiring layer can be provided on the other surface of the first wiring board 51, thereby improving the electrical connection between the first wiring board and the second wiring board. can be done.

Moreover, the manufacturing method of the connection structure may include other steps between, or before and after each of the above steps, as long as they do not adversely affect each of the above steps. For example, a foreign matter removing step for removing foreign matter mixed in during manufacturing may be included.
In addition, in the manufacturing method of the connection structure, the order of some steps is not limited, and the order may be changed. For example, in the first manufacturing method, the conductive member filling step may be performed after the overlapping step is performed. Further, for example, in the second manufacturing method, the overlaying step may be performed after the conductive member coating step is performed.

Further, the method for manufacturing a light-emitting device may include other steps between, or before and after each of the steps, as long as they do not adversely affect each of the steps. For example, a foreign matter removing step for removing foreign matter mixed in during manufacturing may be included.
In addition, in the method for manufacturing a light-emitting device, the order of some steps is not limited, and the order may be changed. For example, the connection structure manufacturing process may be performed after the light guide plate and the intermediate preparation process are performed. Also, the bonding step may be performed after the wiring layer forming step is performed. Further, the wiring layer forming step may be performed when preparing the intermediate.

A connection structure and a light-emitting device according to embodiments of the present disclosure can be used in various electronic devices.

Reference Signs List 1 light emitting structure 2 light emitting element 3 translucent member 4 light diffusion layer 5 coating member 6 light guide plate 6a concave portion 7 light reflecting member 10 light emitting module 11 light source 13 intermediate body 18 wiring pad 19 coating layers 30, 31 conductive member 30a protrusion Part 35 Diffusion reaction layer 40 Protection member 50, 50A, 50B Connection structure 51, 51A First wiring board 52, 52a, 52b, 52aA, 52aB Second wiring board 60 Light emitting part 80 Release paper 90 Alignment pin 100, 100A Light emission Device 111 First substrate 112 Second substrate 121, 121A First wiring layer 122, 122A, 122B, 122C, 122D Second wiring layer 123 Third wiring layer 131 First hole 132 Second hole 133 Third hole 141, 142 alignment holes 151, 151A, 151B wiring layer removed portion 181 via hole A portion D facing the first hole distances L1, L2, L3, L4 between the first wiring layers virtual straight line R1 connecting portion region R2 Light-emitting region W Width of first wiring layer

Claims (15)

A first wiring board having a first wiring layer formed on one surface and having a first hole in a thickness direction at a portion of the first wiring layer, and a second wiring layer formed on one surface and the second wiring a step of preparing a second wiring board having a second hole and a third hole in the thickness direction at a portion of the layer;
filling the first hole with a conductive member such that the conductive member protrudes from the first hole;
stacking the first wiring board and the second wiring board so that the other surface of the first wiring board faces the second wiring layer;
heating and pressurizing the conductive member to electrically connect the first wiring layer and the second wiring layer through the first hole;
In the preparing step, when the first wiring board and the second wiring board are overlapped, the first hole is positioned between the second hole and the third hole in plan view. A method of manufacturing a connection structure of a printed wiring board, wherein the first wiring board and the second wiring board are prepared so as to be arranged. A first wiring board having a first wiring layer formed on one surface and having a first hole in a thickness direction at a portion of the first wiring layer, and a second wiring layer formed on one surface and the second wiring a step of preparing a second wiring board having a second hole and a third hole in the thickness direction at a portion of the layer;
stacking the first wiring board and the second wiring board so that the other surface of the first wiring board faces the second wiring layer;
applying a conductive member to the portion of the first hole on the first wiring board;
heating and pressurizing the conductive member to fill the first hole with the conductive member, and electrically connecting the first wiring layer and the second wiring layer through the first hole; , including
In the preparing step, when the first wiring board and the second wiring board are overlapped, the first hole is positioned between the second hole and the third hole in plan view. A method of manufacturing a connection structure of a printed wiring board, wherein the first wiring board and the second wiring board are prepared so as to be arranged. a first wiring board in which the first wiring layers are provided at predetermined intervals along one direction of the first wiring board in the preparing step, and the first wiring layers have the first holes in respective portions of the first wiring layers; a second wiring board having the second wiring layers provided at predetermined intervals along one direction of the second wiring board, and having the second holes and the third holes in the respective portions of the second wiring layers; 3. The method of manufacturing a connection structure for a printed wiring board according to claim 1 or 2, wherein . In the preparing step, when the first wiring board and the second wiring board are superimposed on each other, the first holes are arranged on the left and right sides of the imaginary straight line extending in the one direction in plan view. 4. The manufacturing method of the connection structure of the printed wiring board according to claim 3, wherein the first wiring board and the second wiring board are prepared so that the wiring layers are arranged alternately on the right and left sides. 5. The first wiring board and the second wiring board according to any one of claims 1 to 4, wherein in the overlapping step, alignment is performed by inserting alignment pins into alignment holes provided in the first wiring board and the second wiring board. 10. A method for manufacturing a connection structure for a printed wiring board according to claim 1. 2. In the preparing step, the second wiring board is prepared, which has a wiring layer removed portion obtained by removing a part of the second wiring layer at a portion facing the first hole in a plan view. 6. The method for manufacturing the connection structure of the printed wiring board according to any one of 5. A step of manufacturing a connection structure by the method for manufacturing a connection structure for a printed wiring board according to any one of claims 1 to 6;
A method of manufacturing a light-emitting device, comprising: the second wiring board having a connection region and a light-emitting region for forming the connection structure; and installing a light-emitting element in the light-emitting region. A light guide plate is prepared, and the light-emitting element is arranged to face the light-emitting region through an opening of a light reflecting member provided in the light-emitting region. providing an intermediate located in the region;
8. The method of manufacturing a light emitting device according to claim 7, further comprising bonding the light guide plate to the intermediate body with the light extraction surface of the light emitting element facing the light guide plate. a first wiring board having a first wiring layer formed on one surface and having a first hole in a thickness direction at a portion of the first wiring layer;
A second wiring substrate having a second wiring layer formed on one surface facing the other surface of the first wiring substrate, and having a second hole and a third hole in the thickness direction at a portion of the second wiring layer. and,
a conductive member arranged in the first hole and electrically connecting the first wiring layer and the second wiring layer;
The connection structure of the printed wiring board, wherein the first hole is arranged at a position sandwiched between the second hole and the third hole in plan view. The first wiring layers are provided at predetermined intervals along one direction of the first wiring substrate, and the second wiring layers are provided at predetermined intervals along one direction of the second wiring substrate,
10. The printed wiring board connection according to claim 9, wherein each portion of the first wiring layer has the first hole, and each portion of the second wiring layer has the second hole and the third hole. Structure. 11. The connection structure for a printed wiring board according to claim 10, wherein the first holes are alternately provided on the right and left sides of the imaginary straight line extending in the one direction in plan view for each of the first wiring layers. 12. The printed wiring board connection structure according to claim 9, wherein the first wiring board is a flexible board, and the second wiring board is a flexible board or a rigid board. 13. The second wiring board according to any one of claims 9 to 12, wherein the second wiring board has a wiring layer removed portion obtained by removing a part of the second wiring layer at a portion facing the first hole in plan view. A printed wiring board connection structure as described. A printed wiring board connection structure according to any one of claims 9 to 13;
A light-emitting device, wherein the second wiring board has a connection region and a light-emitting region for forming the connection structure, and a light-emitting element installed in the light-emitting region. a light guide plate installed facing the second wiring board;
a light reflecting member installed between the light guide plate and the light emitting region;
15. The light-emitting device according to claim 14, further comprising: the light-emitting element arranged in the light-emitting region with the light extraction surface facing the light guide plate through the opening of the light reflecting member.

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