JP2008124099A - Circuit board with radiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board with a radiator capable of being preferably adopted to the circuit board mounting a heat-generating part (an IC) composed of a surface mounting type package. <P>SOLUTION: The radiator 3 for dissipating a heat from electronic parts is bonded and fixed on the other surface of the circuit board 1 mounting the heat-generating electronic parts 2a and 2b on one surface. In the radiator 3, a heat sink 3a bonded on the other surface of the circuit board mounting the electronic parts and radiation fins 3b vertically erected to the heat sink are formed integrally of a metallic raw material, and a large number of through-holes 3c for making air flow are formed on a surface forming the radiation fins 3b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a circuit board provided with a radiator that dissipates heat from a heat-generating component such as an IC chip mounted on the circuit board.

  As electronic devices have become more sophisticated and lighter and thinner in recent years, electronic components have become more densely integrated and more densely packaged. Even in the electronic components mounted on circuit boards, such as microprocessors, etc. Large chips are being developed.

  In addition, in an IC chip typified by the above-described microprocessor or the like, the operating frequency is increased in order to perform processing and control of information at a high speed, and each transistor constituting the processor accompanying this is increased. In addition, there are some cases that generate considerable heat due to repeated high-speed charging and discharging with respect to the parasitic capacitance of the internal wiring.

  For this reason, the operation of each transistor becomes unable to follow the clock frequency and the response frequency due to the heat generated by the device, resulting in an inability to operate. Further, the failure of the entire IC chip due to the heat cannot be recovered. Invite the problem of leaving. Therefore, it is desirable to dissipate heat using a heat radiator in the above-described large-sized IC as well as, for example, a power FET or a power transistor driven by a relatively large current.

In order to dissipate heat from the heat generating components such as the power FET and the power transistor, for example, as disclosed in Patent Document 1 or 2, a heat radiator is provided to the circuit board to which the lead terminals of the heat generating components are connected. And a configuration in which the heat generating component is directly attached to a radiator using a screw or the like has been employed.
Japanese Patent Laid-Open No. 9-246765 JP-A-9-102687

  By the way, in the case of using an element in which a relatively small number of lead terminals are led out in one direction in a part of the package, such as the above-described power FET or transistor, as described in the above-mentioned patent document. Although it is possible to suitably employ a heat dissipation means configured to be directly attached to a heatsink, an IC chip having a surface-integrated package with high density integration as provided in recent years has the same structure. It is impossible to adopt.

  The present invention provides a circuit board on which an IC such as a QFP (QUAD FLAT PACKAGE), BGA (BALL GRID ARRAY), or CSP (CHIP SIZE PACKAGE) type having the above-described surface mount type package is mounted. An object of the present invention is to provide a circuit board with a radiator that can effectively dissipate heat.

  The circuit board with a radiator according to the present invention, which has been made to solve the above-described problems, dissipates heat from the electronic component on the other surface of the circuit board on which a heat-generating electronic component is mounted on one surface. It is characterized in that a radiator for making it adhere is fixed.

  In this case, in the radiator, a heat radiating plate bonded to the other surface of the circuit board on which the electronic component is mounted and a heat radiating fin rising in a vertical direction with respect to the heat radiating plate are integrally formed of a metal material. It is desirable that

  In a preferred embodiment, the radiating fin is formed so that a plurality of plate members rise substantially in parallel with each other in the vertical direction with respect to the radiating plate. In another preferred embodiment, the heat dissipating fins are formed so as to rise in a honeycomb (honeycomb) shape in a direction perpendicular to the heat dissipating plate.

  In any of the above-described configurations, it is desirable that a large number of air circulation through holes are formed on the surface on which the heat radiation fins rising in the vertical direction with respect to the heat radiation plate are formed.

  Further, as the heat radiating fins, those formed by a large number of columnar members rising in the vertical direction with respect to the heat radiating plate can be adopted.

  In addition, the electronic component in the circuit board with a heatsink according to the present invention is a surface-mountable device in which each terminal formed on the electronic component can be connected to a circuit pattern formed on one surface of the circuit board. It is desirable that it is constituted by a mold package.

  According to the circuit board with a radiator described above, the radiator is bonded and fixed to the back surface of the circuit board on which the heat-generating electronic components are mounted. The radiator is attached to the circuit board, and the radiator plate The heat dissipating fins rising in the vertical direction are integrally formed of a metal material.

  Therefore, the heat from the electronic components locally generated on the circuit board is received by the heat radiating plate bonded to the circuit board, so that the heat can be effectively distributed and distributed on the surface of the heat radiating plate. Heat can be effectively radiated by the radiating fins that rise in the vertical direction with respect to the radiating plate.

  In addition, in the radiating fin that rises in the vertical direction with respect to the radiating plate, when the radiating fin is constituted by a plurality of plate members or a wall surface that rises in a honeycomb shape, a large number of air circulations are formed on the wall surface. By forming the through hole, the heat dissipation effect can be further promoted.

  Therefore, according to the circuit board with a radiator having the above-described configuration, an effective heat radiation action can be obtained by applying it to a circuit board on which an IC having a surface mount type package such as QFP, BGA, and CSP type is mounted. Can do.

  Hereinafter, a circuit board with a radiator according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 shows the basic configuration. Reference numeral 1 denotes a circuit board, and a circuit pattern (not shown) is formed on one surface (the upper surface in FIG. 1) of the circuit board 1, for example, a package. QFP type IC (2a) having lead terminals formed on four sides of the package, or a BGA or CSP type IC (2b) in which solder bumps as connection terminals are arranged in a matrix on the back side of the package. The IC is mounted by soldering to the circuit pattern.

  The circuit board 1 constitutes a multilayer circuit board as required, and a flexible lead portion 1a in which a large number of lead lines are assembled is formed on one side of the circuit board 1. A connecting portion 1b is formed at the end of the lead portion 1a. The connecting portion 1b is connected to another substrate or electrode terminal using solder connection or ACF (anisotropic conductive film). Electrically connected.

  On the other surface of the circuit board 1 (the back surface in FIG. 1), a radiator 3 for radiating heat from the IC (2a, 2b) as a heat-generating component is provided with a heat conductive adhesive or heat conduction. The adhesive sheet (not shown) is attached.

  FIG. 2 shows an example (first configuration example) of the radiator 3 shown in FIG. 1, and FIG. 2A shows the entire radiator 3 in a perspective view. 1 is shown in an inverted state. Further, (B) is a cross-sectional view in a state viewed from the aa line shown in (A) in the arrow direction, and (C) is a cross-sectional view in a state viewed from the bb line in FIG. FIG.

  As shown in FIG. 2, the radiator 3 includes a heat radiating plate 3 a bonded to the back surface of the circuit board 1 on which electronic components are mounted, and a heat radiating fin 3 b that rises in a vertical direction with respect to the heat radiating plate 3 a. It is molded integrally. The heat radiator 3 including the heat radiating plate 3a and the heat radiating fins 3b is preferably formed integrally using a material having good heat conduction such as an aluminum material, copper or iron.

  The radiator fin 3b in the radiator 3 shown in FIG. 2 has a plurality of elongated plate members (indicated by the same reference numeral 3b as the radiator fin) in the vertical direction with respect to the radiator plate 3a. It is configured to stand up in a parallel state. Each plate member 3b forming the heat radiating fin is provided with a plurality of air circulation through holes 3c formed in a rectangular shape along the longitudinal direction of the plate member 3b.

  According to the circuit board provided with the radiator 3 having the above-described configuration, the heat generated from the electronic component (IC) mounted on the circuit board is first received by the heat radiating plate 3a, so that the heat is dispersed throughout the heat radiating plate 3a. It works to let you. The heat dispersed on the heat radiating plate surface can be radiated by the heat radiating fins 3b rising in the vertical direction with respect to the heat radiating plate 3a. At this time, as described above, each plate member constituting the heat radiating fins 3b is formed with a large number of through holes 3c for air circulation, so that the heat radiation effect can be further promoted.

  In the embodiment shown in FIG. 2, a rectangular through hole 3c is formed for each of the long plate members 3b constituting the heat radiating fin. The shape of the through hole 3c is as follows. The shape is not limited to this, and any shape can be adopted. Moreover, the formation position of the through-hole 3c can also be changed in each of the long plate members 3b constituting the heat radiating fins.

  FIG. 3 shows another preferred configuration example (second configuration example) of the radiator 3, (A) is a top view showing the entire radiator 3, and (B) is (A) It is sectional drawing of the state seen from the cc line | wire shown to the arrow direction. Furthermore, (C) is a cross-sectional view of the state viewed in the direction of the arrow from the dd line shown in (B).

  The heat radiator 3 shown in FIG. 3 includes a heat radiating plate 3a that is bonded to the back surface of the circuit board 1 on which electronic components are mounted, and heat radiating fins 3b that rise in a honeycomb (honeycomb) shape perpendicular to the heat radiating plate 3a. However, it is integrally formed of a metal material. As this metal material, a material having good heat conduction, such as an aluminum material, copper or iron, is used as in the example described with reference to FIG.

  And many through-holes 3c for air distribution | circulation are formed in the wall surface of the radiation fin 3b which stands | starts up with a honeycomb shape with respect to the radiation plate 3a. In the embodiment shown in FIG. 3, as shown in FIGS. 3B and 3C, rectangular air circulation through holes 3 c are formed on the respective wall surfaces rising in a hexagonal shape.

  Also in the circuit board including the radiator 3 having the configuration shown in FIG. 3, the heat generated from the electronic component (IC) acts to disperse the heat in the heat radiating plate 3a, and the heat dispersed on the surface of the heat radiating plate. Can be effectively radiated by the radiating fins 3b rising in a honeycomb shape with respect to the radiating plate 3a. And since the through-hole 3c for air circulation is formed in the wall surface which stands | starts up in a hexagon shape, the heat dissipation effect can be heightened more.

  In the embodiment shown in FIG. 3, the air circulation through holes 3c are formed on the respective surfaces of the radiating fins 3b rising in a honeycomb shape (hexagonal shape). About the wall surface which forms, it can select suitably. Further, the shape of the through hole 3c is not limited to a rectangular shape, and any shape can be adopted.

  FIG. 4 shows still another configuration example (third configuration example) of the radiator 3, (A) is a top view showing the entire radiator 3, and (B) is (A) It is sectional drawing of the state seen from the ee line shown to the arrow direction.

  The heat radiator 3 shown in FIG. 4 includes a heat radiating plate 3a bonded to the back surface of the circuit board 1 on which electronic components are mounted, and heat radiating fins 3b made up of a number of columnar members that rise in a vertical direction with respect to the heat radiating plate 3a. It is molded integrally with a metal material. As this metal material, a material having good heat conduction, such as an aluminum material, copper or iron, is used as in the example described with reference to FIG.

  Also in the circuit board provided with the radiator 3 having the configuration shown in FIG. 4, the heat generated from the electronic component (IC) acts to disperse the heat in the heat radiating plate 3a, and the heat dispersed on the surface of the heat radiating plate. Can effectively dissipate heat by the radiation fins 3b formed by a large number of columnar members rising in the vertical direction with respect to the radiation plate 3a.

  In the embodiment shown in FIG. 3, the many columnar members constituting the heat radiation fin 3 b are each formed in a columnar shape, but a columnar member formed in a prismatic shape can also be adopted. Further, as for the arrangement configuration of the columnar members rising from the heat radiating plate 3a, other arbitrary arrangement configurations can be adopted without arranging them at equal intervals in the vertical and horizontal directions as shown in FIG.

It is the perspective view which showed the whole structure of the circuit board with a heat radiator concerning this invention. It is the perspective view and sectional drawing which showed the structure of the heat radiator used in the structure shown in FIG. It is the top view and sectional drawing which showed the other structural example of the heat radiator which can be used in this invention. It is the top view and sectional drawing which showed the further another structural example of the heat radiator similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board 1a Lead part 1b Connection part 2a, 2b Heating component (IC)
3 Radiator 3a Heat dissipation plate 3b Heat dissipation fin 3c Through hole

Claims (7)

  A circuit board with a radiator, wherein a radiator for radiating heat from the electronic component is bonded and fixed to the other surface of the circuit board on which one of the heat generating electronic components is mounted.   In the radiator, a heat radiating plate bonded to the other surface of the circuit board on which the electronic component is mounted, and a heat radiating fin rising in a vertical direction with respect to the heat radiating plate are integrally formed of a metal material. The circuit board with a radiator according to claim 1.   3. The circuit board with a radiator according to claim 2, wherein the heat dissipating fin is formed so that a plurality of plate members rise in a substantially parallel state with respect to the heat dissipating plate in a vertical direction. .   3. The circuit board with a radiator according to claim 2, wherein the radiation fins are formed so as to rise in a honeycomb shape in a direction perpendicular to the radiation plate.   5. The heat dissipation according to claim 3, wherein a plurality of through holes for air circulation are formed on a surface of the heat dissipation fin that rises in a vertical direction with respect to the heat dissipation plate. Circuit board with instrument.   The circuit board with a radiator according to claim 2, wherein the radiation fin is formed by a number of columnar members that rise in a vertical direction with respect to the radiation plate.   The electronic component is configured by a surface mount type package in which each terminal formed on the electronic component can be connected to a circuit pattern formed on one surface of the circuit board. The circuit board with a radiator according to claim 1.

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