JP2019140320A - Electronic component mounting board - Google Patents

Abstract

To provide an electronic component mounting board having high radiation performance exhibited by providing a metal block, and having a feature that the metal block is hard to come off the board.SOLUTION: In an electronic component mounting board comprising a backing material composed of insulation resin and having a first principal surface and a second principal surface on the opposite side to the first principal surface, a first conductor layer formed on the first principal surface of the backing material, a second conductor layer formed on the second principal surface of the backing material, a hole penetrating the first conductor layer, the backing material and the second conductor layer, and a metal block inserted into the hole, electronic component mounting parts are provided on the first conductor layer side of the electronic component mounting board, one electronic component mounting part consists of a pair of connection terminals, multiple metal blocks are provided for at least one connection terminal out of the pair of connection terminals, and a through hole conductor for electrically connecting the first and second conductor layers is provided adjacently to each connection terminal.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electronic component mounting board.

Patent Document 1 discloses an electronic component mounting substrate in which a metal block is inserted into a hole penetrating a substrate made of an insulating resin and a substrate made of a conductor layer.
This electronic component mounting substrate can be mounted with a light emitting element such as an LED, and can be used as a light emitting element mounting substrate.

Japanese Patent Laid-Open No. 2006-92358

In the electronic component mounting substrate of Patent Document 1, the heat generated from the electronic component can be radiated by using the metal block.
However, when the size of the metal block is increased in order to improve heat dissipation, there is a problem that the metal block easily comes off from the substrate, and a countermeasure has been demanded.

The present invention has been made in view of such problems, and the present invention has a high heat dissipation performance exhibited by providing a metal block, and has a feature that the metal block is difficult to be removed from the substrate. An object of the present invention is to provide an electronic component mounting board.

That is, the electronic component mounting substrate of the present invention is
A base material comprising an insulating resin and comprising a first main surface and a second main surface opposite to the first main surface;
A first conductor layer formed on the first main surface of the substrate;
A second conductor layer formed on the second main surface of the substrate;
A hole penetrating the first conductor layer, the base material, and the second conductor layer;
An electronic component mounting substrate comprising a metal block inserted into the hole,
An electronic component mounting portion is provided on the first conductor layer side of the electronic component mounting substrate,
One electronic component mounting portion is composed of a pair of connection terminals, and a plurality of metal blocks are provided for at least one connection terminal of the pair of connection terminals,
A through-hole conductor that electrically connects the first conductor layer and the second conductor layer is provided adjacent to each connection terminal.

FIG. 1 is a cross-sectional view schematically showing an example of an electronic component mounting board according to the present invention. FIG. 2 is a cross-sectional view schematically showing another example of the electronic component mounting board. FIG. 3 is a cross-sectional view schematically showing another example of the electronic component mounting board. FIG. 4 is a top view schematically showing an example in which the shape of the metal block is a quadrangular prism in the electronic component mounting board. FIG. 5 is a top view schematically showing an example in which the shape of the metal block is a columnar shape in the electronic component mounting board. FIG. 6 is a cross-sectional view schematically showing an example of a light emitting device in which a light emitting element is mounted on the electronic component mounting substrate of the present invention. FIG. 7 is a diagram for schematically explaining the action of the solder resist. FIG. 8A, FIG. 8B, FIG. 8C, and FIG. 8D are process diagrams schematically showing an example of a method for manufacturing an electronic component mounting board according to the present invention. FIGS. 9A, 9B, and 9C are process diagrams schematically showing an example of a pattern forming process. FIG. 10 is a process diagram schematically showing a gold plating process. FIG. 11 is a process diagram schematically showing a solder resist forming process.

(Detailed description of the invention)
Hereinafter, the present invention will be specifically described. The present invention is not limited to the following description, and can be appropriately modified and applied without departing from the scope of the present invention.

FIG. 1 is a cross-sectional view schematically showing an example of an electronic component mounting board according to the present invention.
An electronic component mounting board 1 shown in FIG. 1 is made of an insulating resin, and includes a base 2 having a first main surface 11 and a second main surface 12 opposite to the first main surface 11, and a base 2. The first conductor layer 21 formed on the first main surface 11 and the second conductor layer 31 formed on the second main surface 12 of the substrate 2 are provided.
An electronic component mounting portion 85 is provided on the first conductor layer 21 side of the electronic component mounting substrate 1. The electronic component mounting portion 85 is a portion surrounded by a dotted line in FIG. 1, but is a portion directly below the electronic component when the electronic component is mounted.
The electronic component mounting portion 85 is provided with a connection terminal 81 and a connection terminal 82 which are a pair of connection terminals.
A plurality of metal blocks are provided for the connection terminal 81 and the connection terminal 82, respectively.
A metal block 51 a and a metal block 51 b are provided for the connection terminal 81, and a metal block 52 a and a metal block 52 b are provided for the connection terminal 82.
The metal blocks are respectively inserted into holes penetrating the first conductor layer, the base material, and the second conductor layer. Specifically, the metal block 51a, the metal block 51b, the metal block 52a, and the metal block 52b are inserted into the holes 61a, 61b, 62a, and 62b, respectively.

A through-hole conductor is provided adjacent to each connection terminal.
A through-hole conductor 41 is provided adjacent to the connection terminal 81, and a through-hole conductor 42 is provided adjacent to the connection terminal 82.
The through-hole conductor 41 includes a positioning hole 43 and a through-hole plating 45 formed on the wall surface of the positioning hole 43. The through-hole conductor 42 includes a positioning hole 44 and a through-hole plating 46 formed on the wall surface of the positioning hole 44.
Further, both the through-hole conductor 41 and the through-hole conductor 42 electrically connect the first conductor layer 21 and the second conductor layer 31.

In the electronic component mounting substrate, it is preferable to provide a metal plating layer on the surface of the metal block on the first conductor layer side and on the surface of the first conductor layer. Moreover, it is preferable to provide the soldering resist formed in the outermost surface by the side of the 1st conductor layer so that an electronic component mounting part may be exposed.
In the electronic component mounting substrate 1 shown in FIG. 1, a metal plating layer 71 a is formed on the surface of the metal block 51 a and the metal block 51 b on the first conductor layer 21 side and the surface of the first conductor layer 21. In a portion where an electronic component is mounted on the metal plating layer 71a, a gold plating layer as a gold layer is provided on the metal plating layer 71a to form a connection terminal 81.
A metal plating layer 72 a is formed on the surface of the metal block 52 a and the metal block 52 b on the first conductor layer 21 side and the surface of the first conductor layer 21. In a portion where an electronic component is mounted on the metal plating layer 72a, a gold plating layer as a gold layer is provided on the metal plating layer 72a to form a connection terminal 82.
Since the electronic component is mounted on the connection terminal 81 and the connection terminal 82, it is a region including a predetermined area including the connection terminal 81 and the connection terminal 82, and directly below the electronic component when the electronic component is mounted. The portion becomes an electronic component mounting portion 85 (a portion surrounded by a dotted line in FIG. 1).
And the solder resist 83 is provided in the outermost surface by the side of the 1st conductor layer 21 so that the electronic component mounting part 85 may be exposed.
A metal plating layer 71b is formed on the surface of the metal block 51a and the metal block 51b on the second conductor layer 31 side and the surface of the second conductor layer 31, and the second conductors of the metal block 52a and the metal block 52b. A metal plating layer 72 b is formed on the surface on the layer 31 side and on the surface of the second conductor layer 31.

Hereinafter, each component constituting the electronic component mounting board will be described.
The electronic component mounting substrate of the present invention has an electronic component mounting portion for mounting electronic components such as light emitting elements on the first conductor layer side. When the electronic component mounting substrate of the present invention is a substrate for mounting a light emitting element, it becomes a light emitting element mounting substrate.
A plurality of connection terminals are provided for one electronic component mounting portion. It is preferable that a cathode-side connection terminal and an anode-side connection terminal are provided for one electronic component mounting portion.
In this case, normally, the cathode-side metal block with respect to the cathode-side connection terminal and the anode-side metal block with respect to the anode-side connection terminal are electrically insulated.
In addition, since a plurality of metal blocks are provided corresponding to one electronic component mounting portion, the heat generated in the electronic component mounting portion can be efficiently radiated to the opposite surface of the electronic component mounting portion. .

The electronic component mounting board includes a metal block inserted into a hole penetrating the first conductor layer, the base material, and the second conductor layer.
Unlike filled vias that are formed in through-holes through a chemical process such as plating, the metal block does not have voids formed therein, and does not have depressions or rises on the surface. Since no void is formed inside, the heat transfer efficiency of the metal block is not reduced, and heat dissipation can be ensured. The metal block is also preferable in that the conductor volume can be easily increased as compared with the filled via.

In the electronic component mounting board of the present invention, a plurality of metal blocks are provided for at least one of the pair of connection terminals. The electronic component mounting substrate 1 shown in FIG. 1 is an example in which a plurality (two) of metal blocks are provided on any of a pair of (two) connection terminals.
By providing a plurality of metal blocks for one connection terminal and increasing the total volume of the plurality of metal blocks, the same high heat dissipation as when one metal block with a large volume is provided is demonstrated. Can be made.
When one metal block with a large volume is provided for one connection terminal and when a plurality of metal blocks are provided so that the total volume of the metal blocks is the same, a plurality of metal blocks are provided. In this case, the ratio of the surface area of the metal block to the volume (weight) of one metal block increases.
Therefore, by providing a plurality of metal blocks, the contact area between the metal block and the surrounding first conductor layer, base material and second conductor layer is increased, and the volume (weight) of one metal block is increased. As a result, the frictional force that the metal block receives from the surroundings increases, and the metal block is less likely to be detached from the electronic component mounting board.
By providing a plurality of metal blocks for one connection terminal, it is possible to remove heat from the electronic component mounting board while exhibiting the same level of heat dissipation as compared to the case where one metal block having a large volume is provided. It can be made difficult.

Moreover, in the electronic component mounting board of the present invention, since a plurality of metal blocks need only be provided for at least one connection terminal of the pair of connection terminals, one of the pair of connection terminals is connected. A plurality of metal blocks may be provided for the terminal, and one metal block may be provided for the other connection terminal.
FIG. 2 is a cross-sectional view schematically showing another example of the electronic component mounting board.
In the electronic component mounting board 101 shown in FIG. 2, two metal blocks, a metal block 151 a and a metal block 151 b, are provided for the connection terminal 181. On the other hand, only one metal block 152 is provided for the connection terminal 182.
Further, the connection terminal 181 is larger than the connection terminal 182. When the shape and size of the electrode of the electronic component connected to the connection terminal are different on the anode side and the cathode side, it is necessary to make the shape and size of the corresponding connection terminal different. The shape and size may be different. And it is good also considering the number of the metal blocks provided with respect to the small connection terminal as one.

The diameters of the plurality of metal blocks provided for one connection terminal may be the same or different. The electronic component mounting board 1 shown in FIG. 1 is an example in which two metal blocks having the same diameter are provided for one connection terminal.
FIG. 3 is a cross-sectional view schematically showing another example of the electronic component mounting board.
In the electronic component mounting board 201 shown in FIG. 3, two metal blocks, a metal block 251a and a metal block 251b, are provided for the connection terminal 281. The diameter of the metal block 251b is larger than the diameter of the metal block 251a. It has become. Two metal blocks, a metal block 252a and a metal block 252b, are provided for the connection terminal 282, and the diameter of the metal block 252a is larger than the diameter of the metal block 252b.

Although the constituent material of a metal block is not specifically limited, It is preferable that it is copper excellent in electrical conductivity and heat conductivity.
In addition, examples of the top shape of the metal block include a substantially circular shape, a substantially elliptical shape, and a substantially polygonal shape (a substantially rectangular shape, a substantially pentagonal shape, a substantially hexagonal shape, a substantially octagonal shape, etc.), and a substantially rectangular shape is preferable. Of the substantially quadrangular shape, a substantially rectangular shape and a substantially square shape are more preferable. It is preferable that the metal block has a columnar shape having such an upper surface shape, that is, a substantially cylindrical shape, a substantially elliptical column shape, or a substantially polygonal column shape.

Moreover, it is preferable that the diameter per metal block is 0.3-1.0 mm among several metal blocks provided with respect to one connection terminal.
The method of determining the diameter of the metal block differs depending on the shape of the upper surface.
When the upper surface shape is circular or substantially circular, it is determined by the diameter. When the upper surface shape is elliptical or substantially elliptical, the major axis is determined.
When the upper surface shape is a polygon or a substantially polygon, it is determined by the length of the longest diagonal line.

Moreover, it is preferable that the space | interval of several metal blocks provided with respect to one connection terminal is 0.4-1.0 mm.
The interval between the metal blocks is determined as the shortest distance between the metal blocks.
When three or more metal blocks are provided for one connection terminal, only the distance to the nearest metal block is measured as the shortest distance between the metal blocks, and the average value is provided for one connection terminal. It is set as the space | interval of several metal blocks to be formed.

When the distance between the metal blocks is 0.4 mm or more, the strength of the conductor layer and the base material between the metal blocks is sufficiently strong, so that the effect of making it difficult for the metal blocks to come out is more exhibited.
Moreover, it is preferable that the space | interval of metal blocks shall be 1.0 mm or less from a viewpoint of improving heat dissipation.

FIG. 4 is a top view schematically showing an example in which the shape of the metal block is a quadrangular prism shape in the electronic component mounting substrate, and FIG. 5 is a diagram in which the shape of the metal block is circular in the electronic component mounting substrate. It is a top view which shows typically the example in the case of columnar shape.
Specific examples of preferred metal block shapes, metal block diameters, and intervals between metal blocks will be described with reference to the drawings.
4 can also be said to be a top view of the electronic component mounting substrate shown in FIG.
Therefore, the metal plating layer and the connection terminal are not shown, but are shown as a top view with the metal block exposed. FIG. 5 also does not show the metal plating layer and the connection terminals, but shows a top view with the metal block exposed.
In the electronic component mounting substrate 1 shown in FIG. 4, the upper surface shape of the metal block 51 a is a substantially rectangular shape, and the diameter of the metal block 51 a is a length indicated by a double arrow W that is a substantially rectangular diagonal line. Moreover, the upper surface shape and diameter of the metal block 51b, the metal block 52a, and the metal block 52b are also the same.
The distance between the metal block 51a and the metal block 51b is the length indicated by the double arrow G.
The interval between the metal block 52a and the metal block 52b is also the same.

In the electronic component mounting substrate 301 shown in FIG. 5, the upper surface shape of the metal block 351 a is substantially circular, and the diameter of the metal block 351 a is the length indicated by the double arrow W that is the diameter of the circle. Further, the top shape and the diameter of the metal block 351b, the metal block 352a, and the metal block 352b are the same.
The distance between the metal block 351a and the metal block 351b is the length indicated by the double arrow G.
The interval between the metal block 352a and the metal block 352b is also the same.

It is preferable that the upper surface shape of the metal block is a substantially rectangular shape (substantially square shape) in that it is more difficult to come off the substrate. Moreover, it is preferable at the point which the insertion to a hole is easy for the upper surface shape of a metal block to be a substantially circular shape. The shape of the metal block can be selected in consideration of the ease of insertion into the required hole and the difficulty of removal from the substrate.

The tip portion of the surface of the metal block on the first conductor layer side can be used as a connection terminal for connecting an electronic component, and an electrode of the electronic component can be disposed thereon.
When the surface of the metal block is used as a connection terminal, the surface of the metal block may be the outermost surface of the connection terminal, or a connection in which a conductor layer is formed by a metal plating layer or a gold plating layer on the surface of the metal block. It may be a terminal.

Moreover, it is preferable that the front-end | tip part of the surface at the side of the 1st conductor layer of a metal block is a flat surface.
When the tip portion of the surface on the first conductor layer side is a flat surface, it is possible to prevent the electronic component to be mounted from tilting when this portion is used as a pad. When the electronic component is a light emitting element, it is possible to prevent the optical axis from being inclined.
Furthermore, it is preferable that the front-end | tip part of the surface at the side of the 1st conductor layer of a metal block forms the same plane as the surface of the 1st conductor layer. If it is the same plane, it is possible to suppress a lateral shift when mounting electronic components and to improve mounting accuracy.

Although it does not specifically limit as insulating resin which comprises a base material in the board | substrate for electronic component mounting, It is preferable that it is an insulating resin provided with a softness | flexibility. Examples of the constituent material of such an insulating resin include polyimide and glass epoxy. Among these, polyimide is preferable. When the insulating resin is polyimide, the insulating resin has both flexibility and insulating properties. Therefore, the shape can be changed according to the application while ensuring sufficient insulation.
Although the thickness of a base material is not specifically limited, It is preferable that it is 30-70 micrometers. When the thickness is smaller than 30 μm, the substrate is easily bent and bent more easily, so that the connection with the wiring and the electronic component is easily broken. On the other hand, if it is larger than 70 μm, cracks are likely to occur around the hole when punching is performed to insert the metal block, and reliability may be lowered.

The constituent materials of the first conductor layer and the second conductor layer in the electronic component mounting substrate are not particularly limited, but are preferably copper, nickel, or the like. These constituent materials have good electrical conductivity and are suitable as conductors.
Although the thickness of a 1st conductor layer and a 2nd conductor layer is not specifically limited, It is preferable that it is thicker than a base material. Moreover, it is preferable that it is 10-300 micrometers. If it is smaller than 10 μm, the conductor layer is easily broken during handling, and the defect rate increases. On the other hand, when the thickness is larger than 300 μm, when the electronic component mounting board is bent and used, the bending stress causes a large compressive stress from the conductor layer to the base material, and thus the base material is easily broken.

The electronic component mounting board includes a through-hole conductor that electrically connects the first conductor layer and the second conductor layer adjacent to each connection terminal.
Electrical connection between the front and back of the substrate can be ensured by the through-hole conductor.
Since a plurality of metal blocks are provided for each connection terminal, it can be said that the through-hole conductor is adjacent to the plurality of metal blocks.
When the through-hole conductor and the metal block are adjacent to each other, it is preferable that the through-hole conductor and the metal block closest to the through-hole conductor have the same potential.
The distance between the through-hole conductor and the metal block closest to the through-hole conductor is preferably 1 to 10 mm. The distance between the through-hole conductor and the metal block can be measured as the length of the straight line where the shortest straight line can be drawn between the through-hole conductor and the metal block when the electronic component mounting board is viewed from above.
One or more through-hole conductors adjacent to the connection terminal may be provided for one connection terminal, and two or more through-hole conductors may be provided.

The through-hole conductor in the electronic component mounting board is preferably formed in a positioning hole for positioning the metal block.

When manufacturing an electronic component mounting board, a positioning hole serving as a reference for determining a position into which the metal block is inserted is separately required.
By positioning the positioning hole into a part of the electronic component mounting board and forming a through-hole conductor in this positioning hole, it is not necessary to secure a separate location for the positioning hole in the raw material board. It is possible to increase the number of electronic component mounting boards from the above. In addition, the electronic component mounting board in which the positional relationship between the through-hole conductor and the metal block is determined to be the same in any substrate can be obtained.

In the electronic component mounting substrate, the ratio of the conductor volume of the through-hole conductor and the conductor volume of the metal block (the conductor volume of the metal block / the conductor volume of the through-hole conductor) is preferably 10 or more.
The conductor volume of the metal block is the total value of the conductor volumes of the metal block provided for one connection terminal.

In the electronic component mounting board, the larger the conductor volume of the metal block, the higher the heat dissipation, which is preferable. On the other hand, the conductor volume of the through-hole conductor is sufficient if it has a size necessary for ensuring conduction between the front and back sides, and it is not necessary to increase it more than necessary from the viewpoint of space saving of the substrate. From the above circumstances, if the ratio of the conductor volume of the through-hole conductor and the conductor volume of the metal block (the conductor volume of the metal block / the conductor volume of the through-hole conductor) is 10 or more, it is possible to ensure heat dissipation and save space on the board. From the viewpoint, the electronic component mounting substrate is preferable.

The through-hole conductor is a conductor formed on the inner wall of a hole (for example, a positioning hole) provided in the base material. Since the through-hole conductor is hollow, the conductor volume of the through-hole conductor is provided in the base material. Smaller than the volume of the hole formed.
On the other hand, since the metal block is inserted so as to fill the whole hole provided in the base material, the volume of the metal block is substantially the same as the volume of the hole provided in the base material.
Therefore, the ratio of the conductor volume of the through-hole conductor and the conductor volume of the metal block is larger than the ratio of the diameter of the through-hole conductor and the diameter of the metal block.

The top surface shape of the through-hole conductor is preferably substantially circular.
4 and 5 also show the shape of the top surface of the through-hole conductor. The top surface of the through-hole conductor 41 provided on the electronic component mounting substrate 1 shown in FIG. 4 and the electronic component mounting substrate 301 shown in FIG. The shape and the top surface shape of the through-hole conductor 42 are both substantially circular.
As a combination of the upper surface shape of the metal block and the upper surface shape of the through-hole conductor, as shown in FIG. 4, the upper surface shape of the metal block is preferably substantially square, and the upper surface shape of the through-hole conductor is preferably approximately circular. Further, as shown in FIG. 5, it is also preferable that the upper surface shape of the metal block is substantially circular and the upper surface shape of the through-hole conductor is substantially circular.

The electronic component mounting board of the present invention preferably includes a solder resist formed on the outermost surface on the first conductor layer side so as to expose the electronic component mounting portion.
The solder resist preferably contains titanium oxide in the pigment.
Titanium oxide is a white pigment, and the solder resist containing titanium oxide can reflect light suitably.

The thickness of the solder resist is preferably 50 to 300 μm. When the thickness of the solder resist is less than 50 μm, thermal deterioration due to heat generated from the electronic component may progress and cracks and defects may occur. On the other hand, if it is larger than 300 μm, when the substrate is bent and used, it becomes impossible to follow the deformation caused by the bending, which may cause a crack.

In the electronic component mounting substrate of the present invention, it is preferable that a metal plating layer is formed on the surface of the metal block on the first conductor layer side and on the surface of the first conductor layer. It is also preferable that a metal plating layer is formed on the surface of the metal block on the second conductor layer side and the surface of the second conductor layer.
The metal plating layer is preferably formed so as to cover the surface of the metal block on the first conductor layer side and the surface of the first conductor layer, and the surface of the metal block on the second conductor layer side and the second conductor layer. It is preferable that it is formed so as to cover the surface.
When the metal plating layer is formed so as to cover the surface of the metal block on the first conductor layer side and the surface of the first conductor layer, and the surface of the metal block on the second conductor layer side and the surface of the second conductor layer The metal plating layer can fix the metal block and make it difficult for the metal block to jump out of the hole.

The metal plating layer is preferably made of at least one metal selected from the group consisting of copper, nickel and silver. When the metal plating layer is copper, the metal plating layer can be formed simultaneously with the through-hole plating for forming the through-hole conductor.
Further, when the metal plating layer is nickel or silver, the metal block, the first conductor layer, and the second conductor layer can be protected from corrosion.
Moreover, it is preferable that a metal plating layer is a layer by which a nickel plating layer and / or a silver plating layer are formed on a copper plating layer.
Moreover, the thickness of the metal plating layer is not particularly limited, but is preferably 1.0 to 10 μm.
When the thickness of the metal plating layer is smaller than 1.0 μm, the conductor layer is easily broken during handling, and the defect rate increases. In addition, if the thickness of the metal plating layer is larger than 10 μm, when the electronic component mounting board is bent and used, the bending will cause a large compressive stress from the metal plating layer and the conductor layer, so that the base material is destroyed. It becomes easy.

In the electronic component mounting substrate of the present invention, a gold plating layer as a gold layer is provided on the metal plating layer in a portion that becomes a connection terminal on the tip portion on the surface of the metal block on the first conductor layer side. Preferably it is.
When the outermost surface of the connection terminal is a gold plating layer, gold can prevent oxidation of the metal plating layer.
Although the thickness of a gold layer is not specifically limited, It is preferable that it is 0.5-3.0 micrometers.
A tin layer may be formed instead of the gold layer.
If the thickness of the gold layer or tin layer is less than 0.5 μm, the thickness is too small to prevent oxidation. Moreover, since gold and tin are soft metals, they are easily deformed. Therefore, if the thickness of the gold layer or tin layer is larger than 3.0 μm, it spreads to the surroundings when deformed and generates compressive stress, which may cause defects such as peeling.

FIG. 6 is a cross-sectional view schematically showing an example of a light emitting device in which a light emitting element is mounted on the electronic component mounting substrate of the present invention.
FIG. 6 shows a light emitting device 100 in which the light emitting element 7 is mounted on the electronic component mounting substrate 1 shown in FIG.
The electrode of the light emitting element 7 is electrically connected to the connection terminal 81 and the connection terminal 82. The portion directly under the light emitting element 7 is the electronic component mounting portion 85, and the solder resist 83 is exposed in portions other than the electronic component mounting portion 85.

As the light emitting element, an LED (light emitting diode) element or an LD (laser diode) can be used. The light emitting element is preferably a surface mount type element.
Since the surface mounting type light emitting element can increase the mounting density, the luminance of light emitted from the light emitting device can be increased when a plurality of light emitting elements are mounted on the electronic component mounting substrate.

The electrode of the light emitting element can be electrically connected to the connection terminal. As an electrode of a light emitting element, that whose outermost surface is a gold layer or a tin layer is preferable.
The connection method between the electrode of the light emitting element and the connection terminal is not particularly limited, and the connection can be made using, for example, solder (not shown).
When the outermost surface of the connection terminal is made of a gold plating layer, when the tin layer is formed on the electrode surface of the light emitting element, the light emitting element and the connection terminal can be connected by eutectic connection of gold and tin.

The electronic component mounted on the electronic component mounting substrate of the present invention is not limited to a light emitting element, and may be a transistor, a capacitor, an IC chip, or the like. These electronic components are also preferably surface-mounted.

FIG. 7 is a diagram for schematically explaining the action of the solder resist.
The light emitting device 100 in which the light emitting element 7 is mounted on the electronic component mounting substrate 1 is covered with a transparent cover 8 for the purpose of protecting the light emitting device.
As shown in FIG. 7, in the light emitting device 100 including the solder resist 83, when the light emitting element 7 emits light, most of the light is transmitted through the cover 8. It is reflected (in FIG. 7, the direction of the arrow indicates the traveling direction of light, and the thickness of the arrow indicates the amount of light). When the solder resist is formed on the electronic component mounting substrate, the reflected light can be reflected again. Accordingly, the luminance can be increased.
The constituent material of the cover 8 is not particularly limited, but is preferably acrylic resin (PMMA), polycarbonate (PC), glass or the like.

Hereinafter, each process of the manufacturing method of the electronic component mounting board | substrate of this invention is demonstrated using drawing.
FIG. 8A, FIG. 8B, FIG. 8C, and FIG. 8D are process diagrams schematically showing an example of a method for manufacturing an electronic component mounting board according to the present invention.

(1) Double-sided conductor substrate preparation step First, as shown in FIG. 8A, a first main surface 11 and a second main surface 12 opposite to the first main surface 11 are provided. A double-sided conductor substrate 5 having a first conductor layer 21 formed on the first main surface 11 of the substrate 2 and a second conductor layer 31 formed on the second main surface 12 is prepared.
Since the materials constituting the base material 2, the first conductor layer 21, and the second conductor layer 31 are the same as those described in the description of the electronic component mounting substrate, description thereof is omitted.

(2) Positioning hole forming step and hole forming step In the positioning hole forming step, a positioning hole penetrating the first conductor layer, the base material and the second conductor layer is formed in the double-sided conductor substrate.
The positioning hole forming step can be performed using punching, drilling, laser, or the like, which is a known method for forming a through-hole conductor.
In the hole forming step, a hole penetrating the first conductor layer, the base material, and the second conductor layer is formed.
The hole forming step is preferably performed by punching.
And it is preferable to perform a positioning hole formation process and a hole formation process simultaneously, and it is more preferable to perform both a positioning hole formation process and a hole formation process simultaneously by punching.
In this case, a punching device is used in which the positioning hole punch for forming the positioning hole and the metal block hole punch for forming the hole are fixed to the same die, and the positional relationship between the punches is fixed. It is preferable.
FIG. 8A and FIG. 8B show a process of simultaneously performing the positioning hole forming process and the hole forming process by punching.
In this example, the positioning hole 43 and the positioning hole 44 are formed by punching from the first conductor layer 21 side by using the positioning hole punch 93 and the positioning hole punch 94, and the hole for forming the metal block is inserted. The hole 61a, the hole 61b, the hole 62a, and the hole 62b are formed by punching using the metal block hole punch 91a, the metal block hole punch 91b, the metal block hole punch 92a, and the metal block hole punch 92b.
FIG. 8A shows a metal block hole punch 91a, a metal block hole punch 91b, a metal block hole punch 92a and a metal block hole punch 92b used for punching, and a positioning hole punch 93 and a positioning hole punch. 94 shows a state in which 94 is fixed to the same die 95 and arranged on the first conductor layer 21 side.
FIG. 8B shows a double-sided conductor substrate in which the positioning hole 43, the positioning hole 44, the hole 61a, the hole 61b, the hole 62a, and the hole 62b are formed.

In punching, it is preferable to form a hole larger in diameter than the positioning hole by making the diameter of the metal block hole punch larger than the diameter of the positioning hole punch.
The diameter of the positioning hole corresponds to the diameter of the through-hole conductor, and the diameter of the hole corresponds to the diameter of the metal block.

Examples of the shape of the upper surface of the hole include a substantially circular shape, a substantially elliptical shape, and a substantially polygonal shape (a substantially rectangular shape, a substantially pentagonal shape, a substantially hexagonal shape, a substantially octagonal shape, etc.). Of the substantially quadrangular shape, a substantially rectangular shape and a substantially square shape are more preferable.
Further, examples of the top shape of the positioning hole include a substantially circular shape, a substantially elliptical shape, and a substantially polygonal shape (a substantially rectangular shape, a substantially pentagonal shape, a substantially hexagonal shape, a substantially octagonal shape, etc.), and a substantially circular shape is preferable.
In addition, the substantially circular shape, the substantially elliptical shape, and the substantially polygonal shape as the upper surface shape of the hole and the positioning hole mean that the meaning is not limited to a circle, an ellipse, or a polygon in a strict sense. In addition to a circle, a substantially circular shape includes a shape in which a circle is slightly distorted. A substantially polygon includes a shape whose corners are slightly rounded. In addition to the exact rectangle and the square, the substantially rectangle and the square each include shapes having slightly different side lengths and angles.

The method of determining the diameter of the hole and the diameter of the positioning hole is the same as the method of determining the diameter of the metal block and the diameter of the through-hole conductor, and is determined based on the shape viewed from above. The specific method of determining the diameter varies depending on the shape of the upper surface.
If the top shape is a circle or a substantially circular shape, it is determined by the diameter. When the upper surface shape is elliptical or substantially elliptical, the major axis is determined.
When the upper surface shape is a polygon or a substantially polygon, it is determined by the length of the longest diagonal line.

The ratio of the positioning hole diameter to the hole diameter (hole diameter / positioning hole diameter) is preferably 1.0 to 3.0, and more preferably 2.5 to 5.5.

The diameter of the positioning hole is preferably 0.3 to 1.0 mm.
Moreover, it is preferable that the diameter of a hole is 0.3-1.0 mm.

(3) Metal block insertion step In the metal block insertion step, the metal block is inserted into the hole with reference to at least two positioning holes formed in the above step, and is filled in the hole.
By inserting the metal block into the hole with the positioning hole as a reference, the positional relationship between the positioning hole and the metal block is accurately determined. An electronic component mounting board in which the positional relationship between the metal block and the through-hole conductor is accurately determined can be manufactured by inserting a metal block into the hole and forming a through-hole conductor in the positioning hole.
In addition, by positioning the positioning hole in a part of the electronic component mounting board and using this positioning hole as a through-hole conductor, there is no need to separately secure a location for the positioning hole in the raw material board. It is possible to increase the number of substrates for mounting electronic components from the substrate.
8C, the metal block 51a is inserted into the hole 61a, the metal block 51b is inserted into the hole 61b, the metal block 52a is inserted into the hole 62a, and the metal block 52b is inserted into the hole 62b from the second conductor layer 31 side. Is shown.
When inserting the metal block into the hole, it is preferable to insert the metal block into the hole from the surface opposite to the surface on which punching has been performed in the hole forming step. When punching is performed from the surface on the first conductor layer side, the metal block is preferably inserted from the surface on the second conductor layer side, and when punching is performed from the surface on the second conductor layer side, the metal block is the first block. It is preferable to insert from the surface on the conductor layer side. This is preferable because the base material is prevented from being bent.

(4) Metal Plating Step As shown in FIG. 8D, metal plating is performed to form through-hole plating 45 and through-hole plating 46 on the wall surface of positioning hole 43 and the wall surface of positioning hole 44, respectively. As a result, the through-hole conductor 41 and the through-hole conductor 42 that electrically connect the first conductor layer and the second conductor layer are formed.
As a method of metal plating, a known method for forming a through-hole conductor can be used, and a method of performing electrolytic copper plating after performing electroless copper plating can be applied.
Also, by this metal plating step, the metal plating layer 70a is formed so as to cover the surface of the metal block on the first conductor layer side and the surface of the first conductor layer, and the surface of the metal block on the second conductor layer side Metal plating layer 70b is formed so as to cover the surface of the two conductor layers.
The formation of the through-hole conductor and the formation of the metal plating layer may be performed by the same metal plating process or may be performed by separate processes.
Moreover, when making the outermost surface of a metal plating layer into at least 1 type of metal selected from the group which consists of nickel and silver, it is preferable to perform a nickel and / or silver plating process.
By forming the outermost surface of the metal plating layer as a nickel plating layer, when the gold plating layer is formed in a later step, the connectivity between the first conductor layer and the gold plating layer can be improved by the nickel plating layer.

If necessary, it is preferable to perform other processes such as a pattern forming process, a pressing process, a coining process, a gold plating process, and a solder resist forming process.
(5) Pattern Forming Process FIGS. 9A, 9B and 9C are process diagrams schematically showing an example of the pattern forming process.
In the pattern forming step, as shown in FIG. 9A, an etching resist 86 is formed on the surfaces of the metal plating layer 70a and the metal plating layer 70b.
Next, as shown in FIG. 9B, the portions of the metal plating layer 70a, the first conductor layer 21, the second conductor layer 31, and the metal plating layer 70b where the etching resist 86 is not formed are removed by etching. To do. The metal plating layer remaining without being removed by etching becomes the metal plating layer 71a and the metal plating layer 72a, and the metal plating layer 71b and the metal plating layer 72b.
Thereafter, the etching resist 86 is removed as shown in FIG. An arbitrary pattern can be formed by such a method.
In the pattern formation step, it is preferable to remove a part of the conductor layer by etching in order to ensure insulation between the connection terminals of the electronic component mounting board.
Examples of the etchant include sulfuric acid-hydrogen peroxide aqueous solution, persulfate aqueous solution such as ammonium persulfate, ferric chloride, cupric chloride, hydrochloric acid and the like. Moreover, you may use the mixed solution containing a cupric complex and an organic acid as etching liquid.

(6) Pressing step It is preferable to control the position of the surface of the metal block with respect to the surface of the first conductor layer by pressing the electronic component mounting substrate using a mold having a predetermined shape. The tip portion of the surface on the first conductor layer side of the metal block becomes a flat surface by pressing.

(7) Coining process It is preferable to perform coining in order to improve the flatness of the surface of the first conductor layer and the surface of the metal block on the first conductor layer side.
When the flatness of the surface of the first conductor layer and the surface of the metal block on the first conductor layer side is increased by coining, the mountability of the electronic component can be improved. Furthermore, when the flatness of the surface of the first conductor layer and the surface of the metal block on the first conductor layer side is high, the optical axes when the light emitting element is mounted as an electronic component are aligned, and the luminance can be increased.

(8) Gold Plating Process FIG. 10 is a process diagram schematically showing the gold plating process.
The gold plating layer was formed on the metal plating layer 71a in the portion to be the connection terminal on the surface of the metal block 51a and the metal block 51b on the first conductor layer 21 side, and the gold layer was formed on the outermost surface. The connection terminal 81 is used.
Similarly, a gold plating layer is formed on the metal plating layer 72a in a portion to be a connection terminal on the surface of the metal block 52a and the metal block 52b on the first conductor layer 21 side, and the gold layer is formed on the outermost surface. The connection terminal 82 is formed.
When the nickel plating layer is formed on the outermost surface of the metal plating layer, an oxide film is formed on the surface of the nickel plating layer, and the electrical connection between the connection terminal and the electrode of the electronic component tends to deteriorate.
Therefore, the connection with the electrode of the electronic component is improved by using the connection terminal having the gold layer formed on the outermost surface.
The gold plating is preferably performed using an electroless gold plating solution.

(9) Solder resist formation process FIG. 11 is a process chart schematically showing a solder resist formation process.
As shown in FIG. 11, a solder resist 83 is formed at a position that is the outermost surface on the first conductor layer 21 side so that the electronic component mounting portion 85 (connection terminal 81 and connection terminal 82) is exposed.
Through the above steps, the electronic component mounting substrate 1 shown in FIG. 1 can be manufactured.
The light emitting element is mounted by connecting the electrode of the light emitting element 7 to the connection terminal of the electronic component mounting substrate 1, whereby the light emitting device of the form shown in FIG. 6 can be obtained.
When forming the solder resist, it is preferable to use a material containing titanium oxide as a pigment. Titanium oxide is a white pigment, and the solder resist containing titanium oxide can reflect light suitably.

DESCRIPTION OF SYMBOLS 1, 101, 201, 301 Electronic component mounting board 2 Base material 5 Double-sided conductor board 7 Light emitting element 8 Cover 11 1st main surface 12 2nd main surface 21 1st conductor layer 31 2nd conductor layer 41, 42 Through Hole conductors 43, 44 Positioning holes 45, 46 Through-hole plating 51a, 51b, 52a, 52b, 151a, 151b, 152, 251a, 251b, 252a, 252b, 351a, 351b, 352a, 352b Metal blocks 61a, 61b, 62a, 62b Hole 70a, 70b, 71a, 71b, 72a, 72b Metal plating layer 81, 82, 181, 182, 281, 282 Connection terminal 83 Solder resist 85 Electronic component mounting part 86 Etching resist 91, 92 Metal block hole punch 93, 94 Positioning hole punch 95 Die 100 Light emitting device

Claims (7)

A base material comprising an insulating resin and comprising a first main surface and a second main surface opposite to the first main surface;
A first conductor layer formed on the first main surface of the substrate;
A second conductor layer formed on the second main surface of the substrate;
A hole penetrating the first conductor layer, the base material, and the second conductor layer;
An electronic component mounting board comprising a metal block inserted into the hole,
An electronic component mounting portion is provided on the first conductor layer side of the electronic component mounting substrate,
One electronic component mounting portion is composed of a pair of connection terminals, and a plurality of metal blocks are provided for at least one connection terminal of the pair of connection terminals,
An electronic component mounting board comprising a through-hole conductor that electrically connects the first conductor layer and the second conductor layer adjacent to each connection terminal. 2. The electronic component mounting board according to claim 1, wherein an upper surface shape of the metal block is substantially rectangular and an upper surface shape of the through-hole conductor is substantially circular. 2. The electronic component mounting board according to claim 1, wherein an upper surface shape of the metal block is substantially circular, and an upper surface shape of the through-hole conductor is substantially circular. The electronic component mounting substrate according to any one of claims 1 to 3, wherein a diameter of each metal block among a plurality of metal blocks provided for one connection terminal is 0.3 to 1.0 mm. The board | substrate for electronic component mounting in any one of Claims 1-4 whose space | interval of the some metal block provided with respect to one connection terminal is 0.4-1.0 mm. The electronic component mounting board according to claim 1, wherein the plurality of metal blocks provided for one connection terminal have different diameters. Furthermore, the electronic component mounting board | substrate in any one of Claims 1-6 provided with the metal plating layer in the surface at the side of the 1st conductor layer of the said metal block, and the surface of the said 1st conductor layer.

Images