JP2012119607A - High heat dissipation substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high heat dissipation substrate exhibiting excellent thermal conductivity in the thickness direction.SOLUTION: A high heat dissipation substrate 100 comprises a planar CFRP plate 1 composed of a carbon fiber-reinforced plastic material, and insulation layers 50a, 50b and circuit layers 51a, 51b formed, respectively, on each side of the CFRP plate 1 by laminating pre-pregs 2a, 2b, 4a, 4b and pre-pregs 5a, 5b, 6a, 6b containing glass cloth, and spreads heat generated from an electronic component 12 mounted on the surface of the circuit layer 51a to the whole substrate by means of the CFRP plate 1. The high heat dissipation substrate 100 has a columnar solid material 10, formed of a metal material, buried to reach the CFRP plate 1 by penetrating the pre-pregs 6a, 5a containing the glass cloth and the pre-pregs 4a, 2a, and fixed to the CFRP plate 1 via a thermally-conductive adhesive 11.

Description

  The present invention relates to a high heat dissipation substrate that is lightweight and excellent in heat dissipation, and particularly relates to a high heat dissipation substrate excellent in thermal conductivity in the thickness direction of the substrate.

  In recent years, printed circuit boards have been desired to have improved heat dissipation as electronic components are mounted with higher density. A metal core substrate has already been put into practical use as a printed circuit board having excellent heat dissipation. The metal core substrate uses a metal such as aluminum or copper having a high thermal conductivity as a core material to dissipate heat from the heat generating component over the entire substrate, thereby suppressing the temperature rise of the heat generating component.

  Recently, carbon fiber reinforced plastics (CFRP) may be used as a core material (see, for example, Patent Document 1). CFRP is a composite material composed of carbon fibers and a resin. If carbon fibers having high thermal conductivity are used, a core material having heat dissipation exceeding that of aluminum and lighter than aluminum can be formed. By using this core material, it is possible to manufacture a printed circuit board (CFRP core board) that is lighter and more radiant than an aluminum core board.

JP 2008-66375 A

  However, since the CFRP core substrate is laminated in the thickness direction of the printed circuit board, the heat conduction in the direction along the plane is good, but the electronic component is mounted on the surface of the printed circuit board. If the thermal conductivity in the thickness direction from the CFRP core material to the CFRP core material is not increased, the heat generated from the electronic component is not easily transmitted to the CFRP core material, which may cause an excessive temperature rise of the electronic component.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the high thermal radiation board | substrate excellent in the thermal conductivity to thickness direction.

  In order to solve the above-described problems and achieve the object, the present invention provides a prepreg formed by laminating a flat core material made of carbon fiber reinforced plastic and a plurality of prepregs, respectively, on both surfaces of the core material. A high heat dissipation substrate that diffuses heat generated in an electronic component mounted on the surface of one prepreg layer to the entire substrate by a core material, and is formed of a metal material and penetrates one prepreg layer. And a columnar heat transfer material that is embedded to reach at least the core material and is fixed to the core material via a heat conductive adhesive.

  According to the present invention, there is an effect that heat can be efficiently conducted in the thickness direction through the buried columnar heat transfer material.

FIG. 1 is a cross-sectional view showing a configuration of a high heat dissipation substrate according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a state where electronic components are mounted on a high heat dissipation substrate. FIG. 3 is a diagram illustrating a configuration example of a high heat dissipation substrate in which a solid material is embedded in a portion in contact with the chassis frame. FIG. 4 is a diagram showing a state in which a high heat dissipation board in which a sleeve-like solid material is embedded is screwed to the chassis frame with screws.

  Embodiments of a high heat dissipation substrate according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a cross-sectional view showing a configuration of a high heat dissipation substrate according to an embodiment of the present invention. The high heat dissipation substrate 100 includes the CFRP plate 1 as a core material, and insulating layers 50a and 50b and circuit layers 51a and 51b are provided on the respective surfaces of the CFRP plate 1.

  The opening periphery (both ends) and the inner wall surface of the through hole 1a provided in the CFRP plate 1 are covered with a copper film 8 as a protective film.

  The insulating layer 50a is formed of the prepreg 2a, the glass cloth 3a, and the prepreg 4a. Similarly, the insulating layer 50b is formed of the prepreg 2b, the glass cloth 3b, and the prepreg 4b. The prepregs 2a and 2b cover both surfaces of the CFRP plate 1 covered with the copper film 8 and the inner wall of the through hole 1a. The glass cloths 3a and 3b are sandwiched between the prepregs 2a and 2b by the prepregs 4a and 4b. The prepregs 2a, 2b, 4a, and 4b are formed as thermosetting resins containing an inorganic filler and do not include glass cloth. Thereby, when laminating the prepregs 2a, 2b, 4a and 4b, the through holes 1a can be filled without voids.

  The circuit layer 51a is formed of a prepreg 5a and a prepreg 6a including a glass cloth. Similarly, the circuit layer 51b is formed of a prepreg 5b and a prepreg 6b including a glass cloth. The prepregs 5a, 5b, 6a, and 6b including a glass cloth have a general configuration in which a glass cloth is impregnated with a thermosetting resin. A wiring layer 7a is provided on the prepreg 6a including the glass cloth, and a wiring layer 7c is provided in a predetermined pattern between the prepregs 5a and 6a including the glass cloth. Similarly, the wiring layer 7b is provided on the prepreg 6b including the glass cloth, and the wiring layer 7d is provided in a predetermined pattern between the prepregs 5b and 6b including the glass cloth.

  Thus, the prepregs 2a and 2b, the glass cloths 3a and 3b, the prepregs 4a and 4b, and the prepregs 5a, 5b, 6a and 6b including the glass cloth are laminated on both surfaces of the CFRP plate 1 which is the core material. Insulating layers 50a and 50b and circuit layers 51a and 51b are formed as layers.

  The high heat dissipation substrate 100 is provided with a signal through hole 9 so as to pass through the center of the through hole 1a. The signal through hole 9 connects the wiring layers 7a, 7b, 7c and 7d. Copper plating is applied to the inner wall portion 9 a of the signal through hole 9. Since both ends and the inner wall surface of the through hole 1a through which the signal through hole 9 passes are covered with the copper film 8 to prevent generation of carbon powder, the insulation reliability between the CFRP plate 1 and the signal through hole 9 is increased. ing.

  A solid material 10 as a columnar heat transfer material is embedded at a position facing the back surface of the package of the electronic component mounted on the substrate. The solid material 10 penetrates the circuit layer 51a, the insulating layer 50a, the CFRP plate 1, the insulating layer 50b, and the circuit layer 51b and is exposed on the front and back of the high heat dissipation substrate 100. The solid material 10 includes a small-diameter portion 101 that penetrates the circuit layer 51a, the insulating layer 50a, and the CFRP plate 1, and a large-diameter portion 102 that penetrates the insulating layer 50b and the circuit layer 51b. A step 103 at the boundary with the diameter portion 102 is in contact with the plate surface of the CFRP plate 1. The solid material 10 is physically and thermally connected to the CFRP plate 1 through a heat conductive adhesive 11. By embedding the solid material 10 via the heat conductive adhesive 11, a minute gap between the solid material 10 and the CFRP plate 1 is filled with the heat conductive adhesive 11. Can be increased. The solid material 10 is formed of a material having high thermal conductivity such as aluminum, copper, or an alloy thereof. Note that the materials exemplified here are merely examples, and other materials can be used.

  FIG. 2 is a diagram illustrating a state in which the electronic component 12 is mounted on the high heat dissipation substrate 100. A heat conductive material 13 is filled between the package of the electronic component 12 and the surface 10a of the solid material 10.

  The heat generated from the electronic component 12 is transmitted from the heat conducting material 13 to the surface 10 a of the solid material 10, and is conducted through the solid material 10 in the thickness direction of the high heat dissipation substrate 100. From the solid material 10, heat is transferred to the CFRP plate 1 through the heat conductive adhesive 11, and heat is diffused in the plane direction of the high heat dissipation substrate 100. Therefore, the heat generated from the electronic component 12 is radiated from the entire high heat dissipation substrate 100. In this way, an excessive temperature rise of the electrical component 12 is suppressed.

  In the above example, the solid material 10 including the small-diameter portion 101 and the large-diameter portion 102 and having a substantially convex axial cross-section is shown. However, the solid material having a substantially rectangular axial cross-section (columnar shape without a step) is shown. Even if it is 10, the same effect is acquired. In addition, by making the axial cross-sectional shape of the solid material 10 substantially convex and bringing the step 103 into contact with the plate surface of the CFRP plate 1, the contact area between the solid material 10 and the CFRP plate 1 is expanded, and the thermal diffusion performance. Can be improved. However, when the solid material 10 is provided with the step 103 and the contact area with the CFRP plate 1 is enlarged, the area occupied by the solid material 10 on the surface where the large-diameter portion 102 of the high heat dissipation substrate 100 is exposed is the other surface ( The surface of the small diameter portion 101 is larger than the exposed surface), and the wiring area is reduced. Therefore, the shape of the solid material 10 may be selected according to which of the thermal diffusion performance and the wiring area is emphasized.

  Further, in the above example, the solid material 10 is embedded directly under the package of the electronic component 12, but the solid material 10 is embedded in a portion where the high heat dissipation substrate 100 and a housing (chassis frame) that accommodates the high heat dissipation substrate 100 abut. Then, the heat diffused in the CFRP plate 1 can be efficiently transmitted to the chassis frame. FIG. 3 is a diagram illustrating a configuration example of the high heat dissipation substrate 100 in which the solid material 10 is embedded in a portion in contact with the chassis frame 14. In the configuration shown in FIG. 3, since the chassis frame 14 serves as a heat sink, the heat diffused in the CFRP plate 1 can be efficiently radiated.

  Further, by making the solid material 10 into a sleeve shape (cylindrical shape) with a hole penetrating in the axial direction, the high heat dissipation substrate 100 can be screwed to the screwing position (screw boss, etc.) of the chassis frame. It is. FIG. 4 is a view showing a state in which the high heat dissipation substrate 100 in which the sleeve-shaped solid material 10 is embedded is screwed to the chassis frame 14 with screws 15.

  Since CFRP has a smaller specific gravity than aluminum, copper, or an alloy thereof, the use of CFRP as a core material can reduce the weight of the high heat dissipation substrate. Furthermore, since CFRP has higher thermal conductivity than aluminum, copper, or alloys thereof, sufficient heat transfer performance can be obtained even when the amount used as a core material is smaller than that of aluminum or the like. Therefore, material usage can be reduced by using CFRP as a core material.

  In the above-described embodiment, the solid material 10 is configured to penetrate through the front and back of the high heat dissipation substrate 100. However, the solid material 10 thermally connects the CFRP plate 1 that is a core material and one surface. It is also possible to have a configuration in which only one surface is exposed without penetrating the high heat dissipation substrate 100. That is, the solid material 10 only needs to penetrate through at least the insulating layer 50a and the circuit layer 51a, or the insulating layer 50b and the circuit layer 51b to reach the CFRP plate 1. However, if the solid material 10 penetrates the front and back of the high heat dissipation substrate 100, the hole for installing the solid material 10 is easier.

  As described above, the high heat dissipation substrate according to the present invention is useful in that the heat generated from the electronic component can be diffused throughout the substrate, or the heat diffused throughout the substrate can be efficiently dissipated to the outside. In particular, it is suitable for high-density mounting of electronic components.

DESCRIPTION OF SYMBOLS 1 CFRP board 2a, 2b, 4a, 4b Prepreg 3a, 3b Glass cloth 5a, 5b, 6a, 6b Prepreg including glass cloth 7a, 7b, 7c, 7d Wiring layer 8 Copper film 9 Signal through hole 9a Inner wall 10 Solid Material 11 Thermal conductive adhesive 12 Electronic component 13 Thermal conductive material 14 Chassis frame 15 Screw 50a, 50b Insulating layer 51a, 51b Circuit layer 100 High heat dissipation substrate 101 Small diameter portion 102 Large diameter portion 103 Step

Claims (7)

An electron mounted on the surface of one of the prepreg layers, comprising a flat core material made of carbon fiber reinforced plastic, and a prepreg layer formed by laminating a plurality of prepregs on both sides of the core material. A high heat dissipation board that diffuses heat generated in a component to the entire board by the core material,
It has a columnar heat transfer material that is formed of a metal material, is embedded so as to reach at least the core material through the one prepreg layer, and is fixed to the core material via a heat conductive adhesive. Features a high heat dissipation board.   The high heat dissipation substrate according to claim 1, wherein the heat transfer material passes through the core material and the other prepreg layer.   The heat transfer material includes a small-diameter portion that penetrates the one prepreg layer and the core material, and a large-diameter portion that penetrates the other prepreg layer, and a step at a boundary between the small-diameter portion and the large-diameter portion. The high heat dissipation substrate according to claim 2, wherein the portion is in contact with a plate surface of the core material. The heat transfer material is embedded at a position corresponding to the mounting position of the electronic component,
The high heat dissipation substrate according to claim 2, wherein a heat conductive material is filled between the heat transfer material and the package of the electronic component.   The heat transfer material has a hole penetrating in the axial direction, is embedded in a position corresponding to a boss of the housing that accommodates the high heat dissipation substrate, and can be screwed to the housing through the hole. The high heat dissipation substrate according to claim 2 or 3, wherein Wiring provided on the prepreg layers on both sides of the core material,
A through hole for conducting the wiring on one surface side of the core material and the wiring on the other surface side of the core material;
The core material includes a through hole filled with a resin forming the prepreg laminated on the surface of the core material, and both end portions and inner walls are covered with a protective film,
6. The high heat dissipation substrate according to claim 1, wherein the through hole is formed through a resin filling the inside of the through hole.   The high heat dissipation substrate according to any one of claims 1 to 6, wherein the metal material is any one of aluminum, copper, an aluminum alloy, and a copper alloy.

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