JP7018967B2 - Heat dissipation board and its manufacturing method - Google Patents

Description

The present invention relates to a heat dissipation substrate and a method for manufacturing the same.

A printed wiring board on which a heat-generating component is mounted is generally provided with a heat dissipation mechanism, for example, as disclosed as the prior art of Patent Document 1. More specifically, the prior art is configured by providing heat generating components and heat sinks on both sides of the substrate so as to sandwich a heat transfer member provided so as to penetrate the substrate. As a result, the heat generated by the heat generating component mounted on one surface of the substrate is transferred to the heat sink arranged on the other surface of the substrate via the heat transfer member and dissipated. At this time, the heat transfer member forming the heat dissipation path between the heat generating component and the heat sink is formed as, for example, a metal piece made of a lump of copper, so that heat is dissipated as compared with the case where a plurality of thermal vias are formed. It is easy to secure the cross-sectional area of the path, and it is possible to efficiently dissipate heat even when the heat generation amount of the heat generating component is relatively large.

In the heat dissipation substrate according to the above-mentioned prior art, the electronic component to be mounted has an electrode terminal on the surface opposite to the contact surface with the substrate, and the electrode terminal is a bonding wire to the conductive pattern formed on the substrate surface. It is connected by. The heat radiating substrate according to the prior art has a heat radiating path formed by embedding a cylindrical heat transfer member in a through hole provided in the wiring board. As described above, the through hole of the heat radiating substrate and the heat transfer member provided in the through hole are generally formed in a cylindrical shape, whereby the formation of the through hole itself or the heat transfer member is crimped or formed. By press-fitting, it becomes easy to provide the through hole without a gap.

Japanese Unexamined Patent Publication No. 2005-051088

By the way, the heat generating component mounted on the heat radiating substrate by the heat transfer member as described above may have a flat plate-shaped electrode terminal on the contact surface with the substrate. In such a case, by arranging the heat transfer member directly under the electrode terminal, heat can be efficiently transferred from the electrode terminal having good thermal conductivity to the heat transfer member.

However, since the electrode terminals formed on the mounting surface of the heat-generating component are not usually formed in a circular shape, in order to provide a heat transfer member having a size in which the entire surface of the electrode terminals is in contact with each other from the viewpoint of heat dissipation efficiency, the electrodes are used. It is necessary to embed a large-diameter heat transfer member that includes the contour of the terminal in the substrate. Therefore, in the heat radiating substrate, there is a possibility that the mounting area for forming other parts and wiring patterns may be compressed, especially around the heat transfer member. On the other hand, when a heat transfer member having a small diameter included in the contour of the electrode terminal is embedded in the substrate, the heat dissipation path may be blocked at the peripheral portion of the electrode terminal where the heat transfer member does not abut, and the heat dissipation efficiency may decrease. Occurs.

The present invention has been made in view of such a situation, and an object thereof is to press the mounting area even when a heat generating component having an electrode terminal is mounted on a contact surface with a substrate. It is an object of the present invention to provide a heat radiating substrate capable of improving heat radiating efficiency without using the above, and a method for manufacturing the same.

The heat-dissipating board according to the present invention is a heat-dissipating board for mounting a heat-generating component having an electrode terminal on a mounting surface, and is composed of a wiring board having a through hole having a circular cross section and a conductive material. The through hole comprises a heat transfer member that constitutes a heat transfer path extending over both sides of the wiring board, and the heat transfer member includes a buried portion fitted inside the through hole and along the surface of the wiring board. The exposed portion is integrally formed with a flat plate-shaped exposed portion provided therein, and the exposed portion has substantially the same shape as the electrode terminal of the heat generating component.

Further, the method for manufacturing a heat transfer board according to the present invention is a method for manufacturing a heat transfer board for mounting a heat generating component having an electrode terminal on a mounting surface, and is a hole for forming a through hole having a circular cross section in the wiring board. A shape in which a forming step, a buried portion in which a heat transfer member made of a conductive material is inserted into the through hole, and a flat plate-shaped exposed portion provided along the surface of the wiring substrate are integrally formed. In the heat transfer member preparation step, the exposed portion of the heat-generating component is included in the heat transfer member preparation step of fitting the embedded portion of the heat transfer member into the through hole. It is processed into substantially the same shape as the electrode terminal.

According to the present invention, even when a heat-generating component provided with an electrode terminal is mounted on a contact surface with a substrate, a heat-dissipating substrate capable of improving heat dissipation efficiency without squeezing the mounting area, and a method for manufacturing the same. Can be provided.

It is sectional drawing of the heat dissipation substrate which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the substrate preparation process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the hole formation process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the plating process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the patterning process which concerns on 1st Embodiment of this invention. It is a perspective view which shows the heat transfer member formed by the heat transfer member preparation process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the fitting process which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the component mounting process which concerns on 1st Embodiment of this invention. It is sectional drawing of the heat dissipation substrate which concerns on 2nd Embodiment of this invention. It is a side view which shows the shape of the heat transfer member which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the hole formation process which concerns on 2nd Embodiment of this invention. It is sectional drawing of the heat dissipation substrate which concerns on 3rd Embodiment of this invention. It is a side view which shows the shape of the heat transfer member which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the hole formation process which concerns on 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described below, and can be arbitrarily modified and implemented without changing the gist thereof. In addition, the drawings used for explaining the embodiments are all schematically showing the constituent members, and are partially emphasized, enlarged, reduced, or omitted in order to deepen the understanding of the constituent members. It may not accurately represent the scale or shape.

<First Embodiment>
FIG. 1 is a cross-sectional view of a heat dissipation substrate 1 according to the first embodiment of the present invention. The heat radiating board 1 is a printed circuit board capable of transmitting heat from the heat generating component 2 to a surface opposite to the mounting surface to dissipate heat when the heat generating component 2 is mounted on the mounting surface of the board, and is a wiring board. A substrate 10, a heat transfer member 20, and a heat sink 30 are provided.

In the present embodiment, the wiring board 10 includes a first outer layer wiring layer 11, a second outer layer wiring layer 12, a plurality of inner layer wiring layers 13, and an insulating layer 14. More specifically, in the wiring board 10, the first outer layer wiring layer 11 is provided on one surface on which the heat generating component 2 is mounted, and the second outer layer wiring layer 12 is provided on the other surface, and between them. A plurality of inner layer wiring layers 13 are formed on the surface. The wiring layers on which the circuit pattern is formed are insulated from each other by the insulating layer 14, and are partially connected by vias (not shown) to form an electronic circuit as the entire substrate.

The wiring board 10 may be a double-sided board on which the inner layer wiring layer 13 is not formed, or may be a multilayer board on which more inner layer wiring layers 13 are formed. Further, although the inner layer wiring layer 13 is formed by patterning in the manufacturing process of the wiring board 10, the illustration is omitted in the present embodiment. Then, in the wiring board 10, a through hole TH having a circular cross section is formed at a position where the heat generating component 2 is mounted, and the heat transfer member 20 is fitted in the through hole TH.

The heat transfer member 20 is a so-called copper inlay made of a metal having conductivity and heat conductivity, for example, copper. As will be described in detail later, the heat transfer member 20 according to the present embodiment extends from the surface of the first outer layer wiring layer 11 to the second outer layer wiring layer 12 via the through hole TH, and extends on both sides of the wiring board 10. It constitutes a heat transfer path.

Here, the heat generating component 2 according to the present embodiment is provided with a flat plate-shaped electrode terminal 2a on the mounting surface on the wiring board 10 side, and is provided with two terminals 2b protruding from the side surface (see FIG. 8). , The surface of the heat transfer member 20 and the electrode terminal 2a are mounted on the wiring board 10 so as to be in contact with each other. More specifically, the heat generating component 2 is, for example, a surface mount type known MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

The heat transfer member 20 is mounted with the heat generating component 2 so that the surface of the wiring board 10 is in contact with the electrode terminal 2a on the surface on which the first outer layer wiring layer 11 is formed. Therefore, the heat from the heat generating component 2 is transferred to the second outer layer wiring layer 12 side via the electrode terminal 2a and the heat transfer member 20, and is dissipated by the heat sink 30 provided in the second outer layer wiring layer 12.

The heat sink 30 can be attached by a heat radiating sheet 20a having thermal conductivity and adhesiveness at a position including the surface of the heat transfer member 20 in the second outer layer wiring layer 12. The heat radiating sheet 20a is in close contact with the heat transfer member 20 and the heat sink 30, so that the heat transfer property from the heat transfer member 20 to the heat sink 30 can be improved and heat can be efficiently dissipated. At this time, when it is necessary to insulate between the heat transfer member 20 and the heat sink 30, a heat dissipation sheet 20a having an insulating property is adopted. Further, instead of the heat radiating sheet 20a, a paste-like heat radiating paste having thermal conductivity may be applied. The heat sink 30 is not essential to the present invention, and may be replaced with a heat radiation pad formed by covering the surface of the heat transfer member 20 and its periphery with a metal layer.

Next, the structure of the heat radiating substrate 1 will be described in more detail while showing the manufacturing method of the heat radiating substrate 1 along with the steps of FIGS. 2 to 8. As an example, the method for manufacturing the heat radiation substrate 1 according to the present embodiment includes a substrate preparation step, a hole forming step, a plating step, a patterning step, a heat transfer member preparation step, a fitting step, and a component mounting step.

FIG. 2 is a cross-sectional view showing a substrate preparation step according to the first embodiment of the present invention. In the substrate preparation step, the first copper foil layer 11'which becomes the first outer layer wiring layer 11 in the later step and the second copper foil layer 12' which becomes the second outer layer wiring layer 12 in the later step are the insulating layer 14. The wiring board 10 formed on both sides of the above is prepared. When the wiring board 10 is a multilayer board, a board including the inner layer wiring layer 13 patterned inside the insulating layer 14 is prepared.

FIG. 3 is a cross-sectional view showing a hole forming step according to the first embodiment of the present invention. In the hole forming step, a through hole TH is provided at the mounting position of the heat generating component 2 with respect to the wiring board 10 prepared in the above-mentioned board preparation step. In the method for manufacturing the heat dissipation substrate 1 according to the present embodiment, the first drill D1 capable of forming a columnar through hole TH in the wiring substrate 10 is used.

FIG. 4 is a cross-sectional view showing a plating process according to the first embodiment of the present invention. In the plating step, copper plating is formed on the inner side surface of the through hole TH formed in the wiring board 10 and the surfaces of the first copper foil layer 11'and the second copper foil layer 12'. As a result, the first outer layer wiring layer 11 and the second outer layer wiring layer 12 are formed on both sides of the wiring board 10, and the wiring layers are connected to each other by plating on the inner side surface of the through hole TH. The plating treatment on the inner surface of the through hole TH and each outer layer wiring layer is performed as necessary, and is not an essential step in the present invention.

FIG. 5 is a cross-sectional view showing a patterning step according to the first embodiment of the present invention. In the patterning step, for example, by known photolithography, the first outer layer wiring layer 11 and the second outer layer wiring layer 12 of the wiring board 10 are processed into a desired circuit pattern.

Subsequently, the heat transfer member preparation process will be described. The heat transfer member preparation step is a step of preparing the heat transfer member 20 of the heat dissipation substrate 1, and is performed separately from the series of processing of the wiring board 10 from the substrate preparation step to the patterning step described above. FIG. 6 is a perspective view showing a heat transfer member 20 formed by the heat transfer member preparation step according to the first embodiment of the present invention.

The heat transfer member 20 according to the present embodiment is made of a metal having a shape in which a buried portion 21 formed in a columnar shape and an exposed portion 22 formed in a flat plate shape are integrally formed, for example, electrical conductivity and electric conductivity. Copper with excellent thermal conductivity can be processed and formed by mold molding.

More specifically, the embedded portion 21 is a portion fitted inside the through hole TH of the wiring board 10 by a press-fitting method or a caulking method in a later step, and has a diameter R and a diameter R according to the dimensions of the through hole TH. The height H is set. Further, the exposed portion 22 has a flat plate shape having substantially the same shape as the electrode terminal 2a of the heat generating component 2 described above when viewed in a plan view, and is provided along the surface of the wiring board 10 in a later step. be.

Then, the heat transfer member 20 is fitted into the through hole TH of the wiring board 10 in the fitting process. FIG. 7 is a cross-sectional view showing a fitting process according to the first embodiment of the present invention. In the fitting process, the heat transfer member 20 formed in the heat transfer member preparation process is pressed against the wiring substrate 10 by the press machine P, so that the embedded portion 21 of the heat transfer member 20 is fitted into the through hole TH. Let me.

Here, in the fitting process, the press-fitting method or the caulking method can be applied. In the press-fitting method, the diameter R of the buried portion 21 of the heat transfer member 20 is made slightly larger than the inner diameter of the through hole TH, and the height H of the buried portion 21 of the heat transfer member 20 is made equal to the thickness of the wiring board 10. Then, it is a method of fixing the buried portion 21 so as to be filled in the through hole TH by the press machine P. Further, in the caulking method, the diameter R of the buried portion 21 of the heat transfer member 20 is made smaller than the inner diameter of the through hole TH, and the height H of the buried portion 21 of the heat transfer member 20 is made higher than the thickness of the wiring board 10. Above, the exposed portion 22 is pressed by the press machine P to deform the embedded portion 21, and the embedded portion 21 is fixed so as to be buried in the through hole TH.

The heat transfer member 20 is fixed to the through hole TH by the fitting process, and the exposed portion 22 is provided along the surface of the wiring board, that is, along the first outer layer wiring layer 11. At this time, when the first outer layer wiring layer 11 by copper plating is formed between the surface of the wiring board 10 and the exposed portion 22, a part of the first outer layer wiring layer 11 is surfaced with the exposed portion 22. By contacting the heat transfer member 20, the electrical conductivity between the heat transfer member 20 and the first outer layer wiring layer 11 can be improved.

Further, when copper plating is formed on the inner side surface of the through hole TH, the contact area between the copper plating and the heat transfer member 20 increases, so that each wiring of the wiring board 10 passes through the copper plating. The electrical conductivity between the layer and the heat transfer member 20 can be improved.

FIG. 8 is a cross-sectional view showing a component mounting process according to the first embodiment of the present invention. In FIG. 8, the components related to the mounting of the heat generating component 2 on the wiring board 10 are schematically shown, and other components such as the patterned first outer layer wiring layer 11 are not shown. .. The heat generating component 2 and its electrode terminal 2a are not limited to the shape shown in FIG. 8, and may have various variations such as a square, a rectangle, a convex shape, a trapezoid, another polygon, and a more complicated shape. is assumed.

In the component mounting process, the solder paste is applied to the surface of the exposed portion 22 of the heat transfer member 20, and the heat generating component 2 is arranged so as to align the electrode terminals 2a via the solder paste, and the heat transfer component 2 is arranged by a known reflow process. The heat transfer member 20 and the heat generating component 2 are connected.

At this time, by forming an electrode pad 15 composed of a part of the first outer layer wiring layer 11 at a position corresponding to the two terminals 2b of the heat generating component 2 on the surface of the wiring board 10, an electrode is formed by reflow processing. The terminals 2a and 2b can be connected to the wiring board 10 at the same time. Then, by connecting the heat sink 30 to the second outer layer wiring layer 12, the heat dissipation substrate 1 shown in FIG. 1 on which the heat generating component 2 is mounted is completed. The heat radiating board 1 is appropriately subjected to other steps common to general printed circuit boards, such as mounting of other electronic components and insulating coating with a solder resist.

As described above, the heat radiating substrate 1 according to the present embodiment has a heat transfer shape in which the embedded portion 21 fitted in the through hole TH and the exposed portion 22 exposed on the surface of the wiring board 10 are integrally formed. The member 20 is provided on the wiring board 10. Since the embedded portion 21 is formed in a columnar shape having a cross section smaller than that of the electrode terminal 2a of the heat generating component 2, other electronic components and wiring arranged around the heat generating component 2 mounted on the wiring board 10 are formed. Does not interfere with the pattern. Further, since the exposed portion 22 is formed in substantially the same shape as the electrode terminal 2a of the heat generating component 2, the embedded portion 21 is integrally and continuously formed while receiving the maximum heat from the heat generating component 2. The heat can be transmitted. As a result, according to the heat radiating substrate 1 according to the first embodiment of the present invention, even when the heat generating component 2 provided with the electrode terminal 2a is mounted on the contact surface with the substrate, the mounting area is not pressed. The heat dissipation efficiency can be improved.

Further, in the heat radiating substrate 1 according to the present embodiment, the first outer layer wiring layer 11 formed by plating comes into surface contact with the exposed portion 22 of the heat transfer member 20 on the surface on which the heat generating component 2 of the wiring substrate 10 is mounted. As a path from the electrode terminal 2a of the heat generating component 2 to the first outer layer wiring layer 11 via the exposed portion 22 of the heat transfer member 20, a conductive path having excellent conductivity and excellent thermal conductivity are provided. It is possible to secure a heat dissipation path.

Further, in the heat radiating substrate 1 according to the present embodiment, a plating layer connected to each wiring layer is formed on the inner surface of the through hole TH, and the plating layer and the heat transfer member 20 are in surface contact with each other. Since the area is increased, it is possible to improve the electrical conductivity of the conductive path from the electrode terminal 2a of the heat generating component 2 to each wiring layer of the wiring substrate 10 via the heat transfer member 20 and the plating layer.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. The heat radiating substrate 3 according to the second embodiment is different from the first embodiment in the shapes of the through hole TH and the heat transfer member 20 in the heat radiating substrate 1 of the first embodiment described above. Hereinafter, the parts different from those of the first embodiment will be described, and the components common to the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 9 is a cross-sectional view of the heat dissipation substrate 3 according to the second embodiment of the present invention. The heat radiating substrate 3 according to the present embodiment has a shape in which the through hole TH provided in the wiring board 10 continuously expands in diameter on the side of the first outer layer wiring layer 11. Further, the heat transfer member 40 fixed to the wiring board 10 is formed according to the shape of the through hole TH.

FIG. 10 is a side view showing the shape of the heat transfer member 40 according to the second embodiment of the present invention. In the heat transfer member 40 according to the second embodiment, the embedded portion 41 fitted in the through hole TH of the wiring substrate 10 and the flat plate-shaped exposed portion 42 provided on the surface of the first outer layer wiring layer 11 are integrated. For example, copper having an excellent electric conductivity and thermal conductivity can be processed by molding to form a metal having a shape of.

Further, in the buried portion 41, a cylindrical portion 41a formed in a columnar shape and an intermediate portion 41b formed in an inverted truncated cone shape are continuously formed, and in the intermediate portion 41b, the columnar portion 41a to the exposed portion 42 are formed. The circular cross section is continuously expanding toward. That is, the side surface S of the intermediate portion 41b is processed into a straight line. In the embedded portion 41 of the heat transfer member 40, the cross-sectional shapes of the cylindrical portion 41a and the intermediate portion 41b are both circular. The exposed portion 42 is formed in a flat plate shape having substantially the same shape as the electrode terminal 2a of the heat generating component 2 when viewed in a plan view, as in the first embodiment described above.

FIG. 11 is a cross-sectional view showing a hole forming step according to the second embodiment of the present invention. In the present embodiment, a second drill D2 as a stepped drill as shown in FIG. 11 is used in order to fit the heat transfer member 40 having the above-mentioned shape into the through hole TH of the wiring board 10. As a result, a through hole TH into which the heat transfer member 40 having the above-mentioned shape can be fitted can be formed by a single drilling process. The heat radiating substrate 3 shown in FIG. 9 is formed by arranging the heat transfer member 40 having the above-mentioned shape with the through hole TH thus formed.

As described above, in the heat radiating substrate 3 according to the second embodiment of the present invention, since the shape of the intermediate portion 41b of the heat transfer member 40 is an inverted truncated cone shape, the through hole TH of the wiring board 10 and the heat transfer member 40 The shape of the above can be easily formed with high accuracy. Further, since the heat transfer member 40 according to the present embodiment is fitted into the through hole TH having no right-angled corners, for example, when a plating layer is formed on the inner surface of the through hole TH, for example, when a plating layer is formed on the inner surface of the through hole TH. At the time of pressing, it is possible to suppress the variation in pressure for each portion on the contact surface with the plating layer. Therefore, the heat radiating substrate 3 according to the second embodiment of the present invention can improve the adhesion between the plating layer and the heat transfer member 40.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. The heat radiating substrate 4 according to the third embodiment is different from the first embodiment in the shapes of the through hole TH and the heat transfer member 20 in the heat radiating substrate 1 of the first embodiment described above. Hereinafter, the parts different from those of the first embodiment will be described, and the components common to the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 12 is a cross-sectional view of the heat dissipation substrate 4 according to the third embodiment of the present invention. The heat radiating substrate 4 according to the present embodiment has a shape in which the through hole TH provided in the wiring board 10 continuously expands in diameter on the side of the first outer layer wiring layer 11. Further, the heat transfer member 50 fixed to the wiring board 10 is formed according to the shape of the through hole TH.

FIG. 13 is a side view showing the shape of the heat transfer member 50 according to the third embodiment of the present invention. In the heat transfer member 50 according to the third embodiment, the embedded portion 51 fitted in the through hole TH of the wiring substrate 10 and the flat plate-shaped exposed portion 52 provided on the surface of the first outer layer wiring layer 11 are integrated. Copper having an excellent electric conductivity and thermal conductivity, which is made of a metal having a shape of the above, can be formed by processing by mold molding.

Further, in the buried portion 51, a cylindrical portion 51a formed in a columnar shape and an intermediate portion 51b extending from the columnar portion 51a to the exposed portion 52 in a shape along an inverted R surface are continuously formed. In the intermediate portion 51b, a circular cross section continuously expands from the cylindrical portion 51a to the exposed portion 52. That is, it is processed into a shape such that the side surface S of the intermediate portion 51b is an inverted R surface. In the embedded portion 51, the heat transfer member 50 has a circular cross-sectional shape of both the cylindrical portion 51a and the intermediate portion 51b. The exposed portion 52 is formed in a flat plate shape having substantially the same shape as the electrode terminal 2a of the heat generating component 2 when viewed in a plan view, as in the first embodiment described above.

FIG. 14 is a cross-sectional view showing a hole forming step according to a third embodiment of the present invention. In the present embodiment, a third drill D3 as shown in FIG. 14 is used in order to fit the heat transfer member 50 having the above-mentioned shape into the through hole TH of the wiring board 10. As a result, a through hole TH into which the heat transfer member 50 having the above-mentioned shape can be fitted can be formed by a single drilling process. The heat radiating substrate 4 shown in FIG. 12 is formed by arranging the heat transfer member 50 having the above-mentioned shape with the through hole TH thus formed.

As described above, since the heat radiating substrate 4 according to the third embodiment of the present invention has the shape of the intermediate portion 51b of the heat transfer member 50 having the side surface S along the inverted R surface, the heat radiating substrate 4 penetrates the wiring board 10. The shapes of the holes TH and the heat transfer member 50 can be easily formed with high accuracy. Further, since the heat transfer member 50 according to the present embodiment is fitted into the through hole TH having no right-angled corners, for example, when a plating layer is formed on the inner surface of the through hole TH, for example, when a plating layer is formed on the inner surface of the through hole TH. At the time of pressing, the pressure on the contact surface with the plating layer can be made uniform so as not to vary from portion to portion. Therefore, the heat radiating substrate 4 according to the third embodiment of the present invention can further improve the adhesion between the plating layer and the heat transfer member 50.

Although the description of the embodiment is completed above, the present invention is not limited to each of the above-described embodiments. For example, in each of the above embodiments, the thickness of the exposed portion of the heat transfer member is not limited, but the shape may be specified so as to increase the thickness according to the amount of heat generated by the heat-generating component to be mounted.

<Embodiment of the present invention>
The first aspect of the present invention is a heat-dissipating substrate for mounting a heat-generating component having an electrode terminal on a mounting surface, which comprises a wiring board having a through hole having a circular cross section and a conductive material. The through hole comprises a heat transfer member constituting a heat dissipation path extending over both surfaces of the wiring board, and the heat transfer member is provided on a buried portion fitted inside the through hole and on the surface of the wiring board. The exposed portion is integrally formed with a flat plate-shaped exposed portion provided along the line, and the exposed portion is a heat radiating substrate having substantially the same shape as the electrode terminal of the heat generating component.

The heat radiating substrate according to the first aspect of the present invention is provided with a through hole at a position on the wiring board on which a heat generating component is mounted, and a heat transfer member fitted in the through hole constitutes a heat radiating path. Here, the heat transfer member has a shape in which an embedded portion fitted in the through hole and an exposed portion exposed on the surface of the wiring board are integrally formed. Since the embedded portion is formed in a columnar shape having a smaller cross section than the electrode terminals of the heat-generating component, it may interfere with other electronic components and wiring patterns arranged around the heat-generating component mounted on the wiring board. There is no. Further, since the exposed portion is formed in substantially the same shape as the electrode terminal of the heat generating component, the heat from the heat generating component is received as much as possible, and the heat is transferred to the integrally and continuously formed embedded portion. Can be done. As a result, according to the heat dissipation substrate according to the first aspect of the present invention, even when a heat generating component having an electrode terminal is mounted on the contact surface with the substrate, the heat dissipation efficiency is improved without squeezing the mounting area. Can be improved.

A second aspect of the present invention is the heat-dissipating substrate in which the surface of the wiring board and the exposed portion are plated with a conductive material in the first aspect of the present invention described above.

According to the heat dissipation substrate according to the second aspect of the present invention, the outer layer wiring layer formed by plating is configured to be in surface contact with the exposed portion of the heat transfer member on the surface on which the heat generating component of the wiring substrate is mounted. Therefore, as a path from the electrode terminal of the heat generating component to the outer layer wiring layer through the exposed portion of the heat transfer member, it is possible to secure a conductive path having excellent conductivity and a heat dissipation path having excellent thermal conductivity.

A third aspect of the present invention is the heat dissipation substrate in which the inner surface of the through hole is plated with a conductive material in the first or second aspect of the present invention described above.

According to the heat dissipation substrate according to the third aspect of the present invention, a plating layer connected to each wiring layer is formed on the inner surface of the through hole, and the plating layer and the heat transfer member are in surface contact with each other. Since the contact area increases, it is possible to improve the electrical conductivity of the conductive path from the electrode terminal of the heat generating component to each wiring layer of the wiring substrate via the heat transfer member and the plating layer.

A fourth aspect of the present invention is the embodiment described in any one of the first to third aspects of the present invention, wherein the embedded portion of the heat transfer member has a cylindrical cylindrical portion and the exposed portion from the cylindrical portion. It is a heat dissipation substrate including an intermediate portion whose cross section continuously expands toward the portion.

According to the heat dissipation substrate according to the fourth aspect of the present invention, the heat transfer member has a circular cross-sectional shape, and from the exposed portion that receives heat from the entire surface of the electrode terminal of the heat generating component to the cylindrical portion having a relatively small diameter. Since the heat transfer member is continuously formed by the intermediate portion, the heat from the heat generating component can be smoothly transferred to the other surface without partially interrupting the heat dissipation path.

A fifth aspect of the present invention is, in the fourth aspect of the present invention described above, the intermediate portion is a heat dissipation substrate that linearly expands from the cylindrical portion to the exposed portion.

According to the heat radiating substrate according to the fifth aspect of the present invention, since the shape of the intermediate portion of the heat transfer member is an inverted conical trapezoidal shape, the through hole of the wiring board and the heat transfer member can be formed accurately. For example, when a plating layer is formed on the inner surface of the through hole, the adhesion between the plating layer and the heat transfer member can be improved.

A sixth aspect of the present invention is, in the fourth aspect of the present invention described above, the heat dissipation substrate in which the intermediate portion expands from the cylindrical portion to the exposed portion in a shape along an inverted R surface. Is.

According to the heat dissipation substrate according to the sixth aspect of the present invention, since the side surface shape of the intermediate portion of the heat transfer member has a shape along the inverted R surface, the heat transfer member is evenly in contact with the inner side surface of the through hole. For example, when a plating layer is formed on the inner surface of the through hole, the adhesion between the plating layer and the heat transfer member can be improved.

A seventh aspect of the present invention is a method for manufacturing a heat transfer substrate for mounting a heat transfer component having an electrode terminal on a mounting surface, which comprises a hole forming step of forming a through hole having a circular cross section on the wiring substrate. A heat transfer member made of a conductive material is processed into a shape in which a buried portion inserted into the through hole and a flat plate-shaped exposed portion provided along the surface of the wiring substrate are integrally formed. The heat transfer member preparation step includes a fitting step of fitting the embedded portion of the heat transfer member into the through hole, and in the heat transfer member preparation step, the exposed portion is referred to the electrode terminal of the heat generation component. It is a method of manufacturing a heat transfer substrate that is processed into substantially the same shape.

In the method for manufacturing a heat radiating substrate according to a seventh aspect of the present invention, a through hole is formed in the wiring board, and a heat transfer member having an embedded portion and an exposed portion is fitted into the through hole. At this time, in the heat transfer member, a cylindrical embedded portion having a smaller cross section than the electrode terminal of the heat generating component and an exposed portion formed in substantially the same shape as the electrode terminal of the heat generating component are integrally and continuously formed. Will be done. As a result, according to the method for manufacturing a heat-dissipating substrate according to the seventh aspect of the present invention, even when a heat-generating component having an electrode terminal on a contact surface with the substrate is mounted, the mounting area is not squeezed. It is possible to form a heat dissipation substrate that can improve the heat dissipation efficiency. Further, according to the method for manufacturing a heat dissipation substrate according to the seventh aspect of the present invention, since the cross section of the through hole is circular, it is possible to form a through hole in the wiring board in one drilling step with a drill. can.

In the eighth aspect of the present invention, in the seventh aspect of the present invention described above, before the fitting step, the surface of the wiring board and the exposed portion are plated with a conductive material to dissipate heat. This is a method for manufacturing a substrate.

According to the method for manufacturing a heat radiating substrate according to the eighth aspect of the present invention, the outer layer wiring layer formed by plating is in surface contact with the exposed portion of the heat transfer member on the surface on which the heat generating component of the wiring substrate is mounted. Therefore, it is possible to secure a conductive path with excellent conductivity and a heat dissipation path with excellent thermal conductivity as a path from the electrode terminal of the heat generating component to the outer layer wiring layer via the exposed portion of the heat transfer member. can.

A ninth aspect of the present invention is the method for manufacturing a heat-dissipating substrate in which the inner surface of the through hole is plated with a conductive material before the fitting step in the seventh or eighth aspect of the present invention described above. Is.

According to the method for manufacturing a heat dissipation substrate according to a ninth aspect of the present invention, the plating layer formed on the inner side surface of the through hole is connected to each wiring layer of the wiring board, and the plating layer and the heat transfer member are connected to each other. By increasing the contact area of the heat-generating component, it is possible to improve the electrical conductivity of the conductive path from the electrode terminal of the heat-generating component to each wiring layer of the wiring board via the heat transfer member and the plating layer.

A tenth aspect of the present invention is the embodiment described in any one of the seventh to ninth aspects of the present invention, wherein in the heat transfer member preparation step, the embedded portion of the heat transfer member is formed into a cylindrical cylinder. This is a method for manufacturing a heat transfer substrate, which is processed into a shape including a portion and an intermediate portion whose cross section continuously expands from the cylindrical portion to the exposed portion.

According to the method for manufacturing a heat radiating substrate according to the tenth aspect of the present invention, the heat transfer member has a circular cross-sectional shape and has a relatively small diameter from the exposed portion that receives heat from the entire surface of the electrode terminal of the heat generating component. Since the heat transfer member is continuously formed by the intermediate part up to the columnar part, the heat dissipation substrate that can smoothly transfer the heat from the heat generating component to the other surface without partially interrupting the heat dissipation path. Can be manufactured.

The eleventh aspect of the present invention is the tenth aspect of the present invention described above, in which the intermediate portion is linearly expanded from the columnar portion to the exposed portion in the heat transfer member preparation step. It is a method of manufacturing a heat transfer substrate to be processed.

According to the method for manufacturing a heat transfer substrate according to the eleventh aspect of the present invention, since the shape of the intermediate portion of the heat transfer member is an inverted truncated cone shape, the through hole of the wiring board and the heat transfer member are accurately formed. For example, when a plating layer is formed on the inner surface of the through hole, the adhesion between the plating layer and the heat transfer member can be improved.

A twelfth aspect of the present invention is the tenth aspect of the present invention, wherein in the heat transfer member preparation step, the intermediate portion is formed along the inverted R surface from the cylindrical portion to the exposed portion. This is a method of manufacturing a heat-dissipating substrate, which is processed into a shape that expands with.

According to the method for manufacturing a heat radiating substrate according to the twelfth aspect of the present invention, the side surface shape of the intermediate portion of the heat transfer member has a shape along the inverted R surface, so that the side surface shape is uniform with respect to the inner side surface of the through hole. Therefore, when a plating layer is formed on the inner surface of the through hole, for example, the adhesion between the plating layer and the heat transfer member can be improved.

1, 3, 4 Heat dissipation board 2 Heat generation component 2a Electrode terminal 10 Wiring board 20 Heat transfer member 21 Embedded part 22 Exposed part TH through hole

Claims (9)

A heat-dissipating board for mounting heat-generating components equipped with electrode terminals on the mounting surface.
A wiring board with a through hole having a substantially circular cross section,
A heat transfer member made of a conductive material and forming a heat dissipation path over both sides of the wiring board in the through hole is provided.
The heat transfer member is integrally composed of an embedded portion fitted inside the through hole and a flat plate-shaped exposed portion provided along the surface of the wiring board.
The exposed portion has substantially the same shape as the electrode terminal of the heat generating component, and has substantially the same shape .
The embedded portion of the heat transfer member is a heat dissipation substrate including a cylindrical portion having a cylindrical shape and an intermediate portion whose cross section continuously expands from the columnar portion to the exposed portion . The heat dissipation substrate according to claim 1 , wherein the intermediate portion linearly expands from the cylindrical portion to the exposed portion. The heat-dissipating substrate according to claim 1 , wherein the intermediate portion expands from the cylindrical portion to the exposed portion in a shape along an inverted R surface. It is a method of manufacturing a heat dissipation board for mounting a heat-generating component having electrode terminals on the mounting surface.
A hole forming process for forming a through hole having a substantially circular cross section on a wiring board,
A heat transfer member made of a conductive material is processed into a shape in which a buried portion inserted into the through hole and a flat plate-shaped exposed portion provided along the surface of the wiring board are integrally formed. Thermal member preparation process and
A fitting step of fitting the embedded portion of the heat transfer member into the through hole by a press-fitting method or a caulking method is included.
In the heat transfer member preparation step, a method for manufacturing a heat radiating substrate, in which the exposed portion is processed into substantially the same shape as the electrode terminal of the heat generating component. The method for manufacturing a heat-dissipating substrate according to claim 4 , wherein the surface of the wiring board and the exposed portion are plated with a conductive material before the fitting step. The method for manufacturing a heat-dissipating substrate according to claim 4 or 5 , wherein the inner surface of the through hole is plated with a conductive material before the fitting step. In the heat transfer member preparation step, the embedded portion of the heat transfer member has a shape including a cylindrical portion and an intermediate portion whose cross section continuously expands from the columnar portion to the exposed portion. The method for manufacturing a heat transfer substrate according to any one of claims 4 to 6 , which is processed in 1. The method for manufacturing a heat dissipation substrate according to claim 7 , wherein in the heat transfer member preparation step, the intermediate portion is processed into a shape that linearly expands from the cylindrical portion to the exposed portion. The method for manufacturing a heat dissipation substrate according to claim 7 , wherein in the heat transfer member preparation step, the intermediate portion is processed into a shape that expands in a shape along an inverted R surface from the cylindrical portion to the exposed portion.

Images