JP6249931B2 - Circuit board, circuit board heat dissipation structure, and circuit board manufacturing method - Google Patents

Description

  The present invention relates to a circuit board having an electronic component mounted on an upper surface and a heat transfer member for radiating heat generated in the electronic component.

  Various structures have been proposed for dissipating heat generated by the mounted electronic components on a circuit board on which electronic components are mounted on the upper surface of a plate-like insulating substrate and a wiring pattern is formed.

  For example, in the circuit board of Patent Document 1, a heat transfer element which is a solid body of copper is embedded so as to penetrate an insulating base. A heat conductive and insulating layer is coated on the upper surface of the heat transfer element, and a heat-generating semiconductor chip is mounted on the layer. A copper layer is deposited on the lower surface of the insulating substrate, and the copper layer and the heat transfer element are in contact with each other.

  Further, in the circuit board of Patent Document 2, one or more metal heat dissipating bodies having a convex longitudinal section are embedded so as to penetrate the insulating base. A heating element is mounted on the upper surface having a smaller area than the lower surface of the metal radiator, and an electronic component other than the heating element is mounted on the upper surface of the insulating base. An insulating layer having a high thermal conductivity is formed on the lower surface of the insulating base and the lower surface of the metal radiator, and a metal layer made of copper foil is formed on the lower surface of the insulating layer.

  Further, in the circuit board of Patent Document 3, insulating layers are formed on both upper and lower surfaces of a flat CFRP plate made of carbon fiber reinforced plastic, and on the surface of each insulating layer (the surface opposite to the CFRP plate), A circuit layer is formed. Further, a solid metal columnar material having a convex longitudinal section is embedded so as to penetrate the circuit board. An electronic component is mounted on the upper surface of the solid material via a heat conductive material. A chassis frame is brought into contact with the lower surface of the solid material so that the chassis frame functions as a heat sink.

  Furthermore, in the circuit board of Patent Document 4, an electronic component mounting area is provided on the upper surface of the insulating base, and a heat transfer member is embedded in the insulating base. The heat transfer member is provided at a position overlapping the mounting region in plan view, and includes a first heat transfer unit, a second heat transfer unit, a side heat transfer layer, or a lower surface heat transfer layer. The first heat transfer unit has an upper surface and a lower surface having a smaller area than the upper surface. The second heat transfer section is provided so as to be exposed from the first heat transfer section to the side surface of the insulating base. The side heat transfer layer is provided on the side surface of the insulating base and is in contact with the second heat transfer portion. The lower surface heat transfer layer is provided on the lower surface of the insulating base and is in contact with the side surface heat transfer layer.

JP 2006-49887 A JP 2008-251671 A JP 2012-119607 A JP 2014-157949 A

  When a heat transfer member is provided inside or on the lower surface of the insulating base as in the past, the heat generated by the electronic components mounted on the upper surface of the circuit board is diffused throughout the circuit board by the heat transfer member, and the circuit board It is possible to dissipate heat downward. However, depending on the number and shape of the heat transfer members, the number of circuit board manufacturing steps increases, making it difficult to manufacture the circuit board.

  An object of the present invention is to facilitate the manufacture of a circuit board while improving the heat dissipation of the circuit board.

In the circuit board according to the present invention, the mounting area of the heat generating electronic component and the wiring pattern are provided on the upper surface of the plate-like insulating base, and the first heat transfer member having a vertical cross-sectional shape having a convex shape and a larger diameter from the upper part is insulated. A plate-like second heat transfer member is embedded in the base and provided on the lower surface of the insulating base. The first heat transfer member is provided at a position overlapping with the mounting region, and the lower surface of the first heat transfer member is exposed from the lower surface of the insulating base, the thickness of the lower portion of the first heat transfer member, and the second heat transfer The thickness of the member is the same. An insulating base is interposed between the upper surface of the first heat transfer member and the mounting area, and an inner layer inside the insulating base, a wiring pattern in the inner layer, and a second conduction portion are provided. . The second conduction portion conducts the wiring pattern between the upper surface of the first heat transfer member and the mounting area and the wiring pattern provided in the mounting area.

  According to the present invention, the heat generated in the electronic component mounted on the mounting region on the upper surface of the circuit board is transferred to the first heat transfer member located immediately below, and further, the heat is transferred from the first heat transfer member to the insulating substrate and the second heat transfer member. 2 It is transmitted to the heat transfer member and diffuses throughout the circuit board. At this time, the diameter of the lower part is larger than the diameter of the upper part of the first heat transfer member, and the thickness of the lower part of the first heat transfer member and the second heat transfer member are the same. It is efficiently transmitted from the lower part to the insulating base and the second heat transfer member. Then, heat can be dissipated to the outside from the lower surface of the first heat transfer member and the lower surface of the second heat transfer member exposed from the insulating base, and the heat dissipation of the circuit board can be improved. Further, since the thickness of the lower part of the first heat transfer member and the second heat transfer member are the same, a plate-like insulating base is easily adhered to the gap or upper part of the first heat transfer member and the second heat transfer member. The heat member and the insulating base can be integrated. Moreover, since the longitudinal cross-sectional shape of the 1st heat transfer member is convex shape, the contact area of a 1st heat transfer member and an insulation base | substrate becomes large, and even if it does not take another countermeasure, the 1st heat transfer member and The adhesive strength with the insulating substrate can be increased. For this reason, it is possible to facilitate the manufacture of the circuit board while suppressing an increase in the manufacturing process of the circuit board.

In the present invention, in the circuit board, the first conduction portion is provided so as to pass through the wiring pattern on the upper surface of the insulating base and the insulating base while passing through the second heat transfer member or the lower portion of the first heat transfer member. The first conduction part may conduct the wiring pattern on the upper surface of the insulating base and the second heat transfer member or the first heat transfer member.

  In the present invention, in the circuit board, a wiring pattern is provided on the surface layer on the upper surface of the insulating base and the inner layer on the inner side, and the first conductive portion includes the wiring pattern on the surface layer, the wiring pattern on the inner layer, and the insulating base. While passing through, the second heat transfer member or the lower portion of the first heat transfer member may be penetrated, and the surface layer wiring pattern, the inner layer wiring pattern, and the second heat transfer member or the first heat transfer member may be conducted.

  In the present invention, the lower part of the 1st heat transfer member and the 2nd heat transfer member may be connected in the above-mentioned circuit board.

  Further, in the heat dissipation structure of the circuit board according to the present invention, a radiator is attached to the lower surface of the circuit board, and between the upper surface of the radiator and the lower surface of the first heat transfer member or the lower surface of the second heat transfer member, A sheet-like third heat transfer member having insulating properties is provided.

  In the method for manufacturing a circuit board according to the present invention, the second heat transfer member is formed with a through hole having a diameter larger than the lower portion of the first heat transfer member, and the first heat transfer member is formed in the through hole. The lower part of the first heat transfer member is inserted, and the gap between the lower part of the first heat transfer member and the second heat transfer member, the upper surface of the second heat transfer member, and at least the periphery of the first heat transfer member are filled with an insulating base. Thereafter, a mounting region and a wiring pattern are formed on the upper surface of the insulating substrate.

  In the circuit board manufacturing method, a plurality of crosspieces are formed between the inner peripheral surface of the through hole of the second heat transfer member or the lower portion of the first heat transfer member, and the first hole is formed in the through hole. The lower part of the heat transfer member is inserted, each crosspiece is fixed to the inner peripheral surface of the through hole or the lower part of the first heat transfer member, the gap between the lower part of the first heat transfer member and the second heat transfer member, 2 The upper surface of the heat transfer member and at least the periphery of the first heat transfer member may be filled with an insulating base, and then a predetermined crosspiece may be cut.

  ADVANTAGE OF THE INVENTION According to this invention, manufacture of a circuit board can be made easy, improving the heat dissipation of a circuit board.

It is a top view of the circuit board of a 1st embodiment of the present invention. It is sectional drawing of the circuit board of 1st Embodiment of this invention. It is the perspective view which showed one manufacturing process of the circuit board of 1st Embodiment of this invention. It is sectional drawing which showed one manufacturing process of the circuit board of 1st Embodiment of this invention. It is sectional drawing of the circuit board of 2nd Embodiment of this invention. It is the perspective view which showed one manufacturing process of the circuit board of 2nd Embodiment of this invention. It is sectional drawing which showed one manufacturing process of the circuit board of 2nd Embodiment of this invention. It is a top view of the circuit board of a 3rd embodiment of the present invention. It is sectional drawing of the circuit board of 3rd Embodiment of this invention. It is sectional drawing of the circuit board of 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals are given to the same parts and corresponding parts.

  First, the structure of the circuit board 1 of 1st Embodiment is demonstrated, referring FIG. 1 and FIG. FIG. 1 is a plan view of a circuit board 1 according to the first embodiment. FIG. 2 is a cross-sectional view of the circuit board 1 of the first embodiment.

  As shown in FIGS. 1 and 2, the circuit board 1 includes an insulating base 2, a metal inlay 3, a metal core 4, wiring patterns 5a to 5e, 5g, 5s, and vias 6a to 6c.

  The insulating base 2 is made of an epoxy resin containing glass fiber, has an insulating property, and is formed in a plate shape. By laminating a plurality of insulating bases 2, two inner layers Lb and Lc are provided inside the insulating base 2, and a surface layer La is provided on the upper surface of the insulating base 2.

  The surface layer La is provided with an electronic component mounting region R and wiring patterns 5s, 5g, and 5d. The wiring patterns 5s, 5g, and 5d are made of copper foil having electrical conductivity and thermal conductivity. In the mounting region R, an FET (field effect capacitor) 7 is mounted. The FET 7 generates heat during the switching operation. The FET 7 is an example of the “electronic component” in the present invention.

  The tip of the source terminal 7s of the FET 7 is connected to the wiring pattern 5s by solder 8. The tip of the gate terminal 7g of the FET 7 is connected to the wiring pattern 5g by solder 8.

  In the inner layer Lb, wiring patterns 5a and 5b are provided. The inner layer Lc is provided with wiring patterns 5c and 5e. The wiring patterns 5a, 5b, 5c, and 5e are made of copper foil having electrical conductivity and thermal conductivity.

  The wiring pattern 5d of the surface layer La and the wiring patterns 5b and 5e of the inner layers Lb and Lc are provided at positions that overlap vertically (in the thickness direction of the insulating base 2) in FIG. The wiring pattern 5s of the surface layer La and the wiring patterns 5a and 5c of the inner layers Lb and Lc are also provided at positions that overlap vertically in FIG.

  The metal inlay 3 is made of a forged product of metal such as copper having electrical conductivity and thermal conductivity. As another example, the metal inlay 3 may be formed by cutting or casting a metal such as copper having electrical conductivity and thermal conductivity. The metal inlay 3 has a rectangular shape when viewed from above or below, and has a vertical cross-sectional shape that is convex as shown in FIG. The lower part 3b of the metal inlay 3 protrudes in a bowl shape laterally with respect to the upper part 3a. For this reason, the diameter of the lower part 3b is larger than the diameter of the upper part 3a of the metal inlay 3.

  The metal inlay 3 is embedded in the insulating base 2 so as to penetrate the insulating base 2. The upper surface of the metal inlay 3 is exposed from the upper surface of the insulating base 2. The lower surface of the metal inlay 3 is exposed from the lower surface of the insulating base 2.

  The metal inlay 3 is provided at a position overlapping the mounting region R in the vertical direction. The mounting region R is provided so as to extend from the upper surface of the metal inlay 3 to a part of the upper surface of the insulating base 2 and a part of the upper surface of the wiring patterns 5d, 5g, and 5s. The body 7 a and the drain terminal 7 d of the FET 7 are connected to the upper surface of the metal inlay 3 by solder 8.

  The lower part 3b of the metal inlay 3 is provided at a position that overlaps the ends of the wiring patterns 5a to 5e, 5g, and 5s. The metal inlay 3 is an example of the “first heat transfer member” in the present invention.

  The metal core 4 is made of a metal plate material such as copper having electrical conductivity and thermal conductivity. The metal core 4 is provided on the lower surface of the insulating base 2 so as to spread in a direction parallel to the plate surface of the insulating base 2.

  In FIG. 2, the right part 4a and the left part 4b of the metal core 4 are insulated. The right portion 4a of the metal core 4 and the wiring patterns 5s, 5g, 5a, and 5c are provided at positions that overlap vertically. The left portion 4b of the metal core 4 and the wiring patterns 5d, 5b, and 5e are also provided at positions that overlap vertically.

  The thickness of the metal core 4 and the thickness of the lower part 3b of the metal inlay 3 are the same. Moreover, the thickness of the metal core 4 and the lower part 3b of the metal inlay 3 is thicker than the thickness of the wiring patterns 5a-5e, 5g, and 5s. The metal core 4 is an example of the “second heat transfer member” in the present invention.

  An insulating base 2 is interposed between the metal core 4 and the lower part 3 b of the metal inlay 3. The insulating substrate 2 is also interposed between the upper part 3a of the metal inlay 3 and the wiring patterns 5a, 5b, 5c and 5e of the inner layers Lb and Lc. The upper part 3a of the metal inlay 3 and the wiring patterns 5d, 5g, 5s of the surface layer La are separated from each other.

  A plurality (two) of vias 6a are provided so as to penetrate the wiring pattern 5s of the surface layer La, the wiring patterns 5a and 5c of the inner layers Lb and Lc, the insulating base 2, and the right part 4a of the metal core 4. The via 6a makes the wiring patterns 5s, 5a, 5c and the right part 4a of the metal core 4 conductive. The right part 4a of the metal core 4 functions as a wiring pattern through which the source current of the FET 7 flows.

  A plurality (two) of vias 6 b are provided so as to penetrate the wiring pattern 5 d of the surface layer La, the wiring patterns 5 b and 5 e of the inner layers Lb and Lc, the insulating base 2, and the left portion 4 b of the metal core 4. The via 6b conducts the wiring patterns 5d, 5b, and 5e and the left part 4b of the metal core 4.

  A plurality (two) of vias 6c are provided so as to penetrate the wiring pattern 5d of the surface layer La, the wiring patterns 5b and 5e of the inner layers Lb and Lc, the insulating base 2, and the lower portion 3b of the metal inlay 3. The via 6c makes the wiring patterns 5d, 5b, 5e and the metal inlay 3 conductive.

  The metal inlay 3 and the left part 4b of the metal core 4 are electrically connected via the wiring patterns 5d, 5b, and 5e and the vias 6b and 6c. The metal inlay 3 and the left part 4b of the metal core 4 function as a wiring pattern through which the drain current of the FET 7 flows. The vias 6a, 6b, and 6c are examples of the “first conductive portion” in the present invention.

  A heat sink 9 is attached to the lower surface of the circuit board 1 with screws 11. The heat sink 9 cools the circuit board 1 by releasing heat generated in the circuit board 1 to the outside. The heat sink 9 is an example of the “heat radiator” in the present invention.

  Between the upper surface of the heat sink 9 and the lower surface of the metal inlay 3, an insulating heat radiating sheet 10 having insulating properties and thermal conductivity is provided. The insulating heat dissipation sheet 10 is also extended between the upper surface of the heat sink 9 and the lower surface of the metal core 4. The insulating heat radiation sheet 10 is an example of the “third heat transfer member” in the present invention.

  Next, a method for manufacturing the circuit board 1 according to the first embodiment will be described with reference to FIGS. FIG. 3 is a perspective view showing one manufacturing process of the circuit board 1 of the first embodiment. FIG. 4 is a cross-sectional view showing one manufacturing process of the circuit board 1 of the first embodiment.

  As shown in FIG. 3A, the metal inlay 3 is formed so as to have a rectangular shape in plan view, and is formed so that the diameter of the lower part 3b is larger than the diameter of the upper part 3a. Further, the metal core 4 is formed to have the same thickness as the thickness of the lower portion 3 b of the metal inlay 3. Further, the metal core 4 is formed with a rectangular through hole 4 h having an inner diameter larger than the outer diameter of the lower portion 3 b of the metal inlay 3.

  First, as shown in FIG. 4A, the lower surface of the metal core 4 is installed on the horizontal reference plane A, and the lower portion 3b of the metal inlay 3 is inserted into the through hole 4h of the metal core 4 (FIG. 3B). See also)). At this time, the lower surface of the metal core 4 and the lower surface of the metal inlay 3 are flush with each other. Next, as shown in FIG. 4B, the gap between the lower part 3 b of the metal inlay 3 and the metal core 4 is filled with the insulating base 2, and the insulating base is formed on the upper surface of the metal core 4 and the upper face of the lower part 3 b of the metal inlay 3. 2 is bonded.

  Next, after a circuit such as a wiring pattern is formed on the upper surface of the insulating substrate 2 by printing, the inner layers Lc and Lb are formed by repeating the process of further bonding the insulating substrate 2 thereon (FIG. 4C). ). At this time, the upper surface of the metal inlay 3 is exposed from the upper surface of the insulating base 2. Further, a circuit such as a wiring pattern is formed on the upper surface of the insulating substrate 2 by printing, and an electronic component mounting region R is formed around the upper surface of the metal inlay 3 to constitute the surface layer La (FIG. 4C). .

  Next, vias 6 a to 6 c are formed so as to penetrate predetermined wiring patterns 5 a to 5 e, 5 g and 5 s and the metal core 4 or the metal inlay 3. And the metal core 4 (refer FIG.3 (b)) is cut | disconnected and the right part 4a and the left part 4b are insulated (FIG.4 (d)). The metal core 4 may be formed with a notch, a notch, a perforated hole, or the like between the right part 4a and the left part 4b in advance so that the right part 4a and the left part 4b can be easily cut.

  Through the above process, the gap between the lower part 3 b of the metal inlay 3 and the metal core 4, the upper surface of the metal core 4, and the periphery of the metal inlay 3 are filled with the insulating base 2. Then, the metal inlay 3, the metal core 4, and the insulating base 2 are integrated to form the circuit board 1.

  Thereafter, as shown in FIGS. 1 and 2, the FET 7 is mounted on the mounting region R on the upper surface of the circuit board 1, and the heat sink 9 is attached to the lower surface of the circuit board 1 via the insulating heat dissipation sheet 10.

  According to the first embodiment, when the FET 7 mounted on the mounting region R on the upper surface of the circuit board 1 is operated, the heat generated in the FET 7 is transmitted from the body 7a and the drain terminal 7d of the FET 7 to the metal inlay 3. Can do. In particular, since the FET 7 is mounted on the upper surface of the metal inlay 3, the heat generated in the FET 7 can be efficiently transmitted to the metal inlay 3. Then, heat can be efficiently transmitted from the large-diameter lower portion 3b of the metal inlay 3 to the heat sink 9 via the insulating heat radiating sheet 10, and heat can be dissipated from the heat sink 9 to the outside.

  In addition, heat can be transmitted from the metal inlay 3 to the wiring patterns 5a to 5c, 5e of the inner layers Lb and Lc and the metal core 4 through the insulating base 2 and diffused throughout the circuit board 1. Then, heat can be efficiently transferred from the metal core 4 having a large area to the heat sink 9 via the insulating heat-radiating sheet 10, and heat can be dissipated from the heat sink 9 to the outside.

  Further, the heat transferred from the FET 7 to the wiring patterns 5s and 5d of the surface layer La through the terminals 7s and 7d is transferred to the wiring patterns 5a to 5c and 5e of the inner layers Lb and Lc and the metal core 4 through the vias 6a to 6c. The heat can be diffused throughout the metal inlay 3 and the circuit board 1. Then, heat can be efficiently transmitted from the metal inlay 3 or the metal core 4 to the heat sink 9 via the insulating heat dissipation sheet 10, and heat can be dissipated from the heat sink 9 to the outside. Further, the heat of the wiring patterns 5s, 5g, and 5d can be dissipated from the surface of the wiring patterns 5s, 5g, and 5d to the outside.

  In addition, since the thickness of the lower part 3b of the metal inlay 3 and the thickness of the metal core 4 are the same, the plate-like insulating base 2 is easily bonded to the gap or the upper part, so that the metal inlay 3, the metal core 4 and the insulating base 2 Can be integrated. Further, since the vertical cross-sectional shape of the metal inlay 3 is convex, the contact area between the metal inlay 3 and the insulating base 2 is increased, and the metal inlay 3 and the insulating base 2 can be connected without taking additional measures. Adhesive strength can be increased. And it can suppress that the manufacturing process of the circuit board 1 increases.

  As described above, it is possible to improve the heat dissipation of the circuit board 1 and to easily manufacture the circuit board 1.

  Moreover, in the said 1st Embodiment, the right part 4a and the left part 4b of the metal core 4 and the metal inlay 3 are combined as a wiring pattern. Therefore, the FET 7 is included by using the wiring patterns 5d, 5g, 5s of the surface layer La, the wiring patterns 5a-5c, 5e of the inner layers Lb, Lc, the right part 4a, the left part 4b of the metal core 4, and the metal inlay 3. An electrical circuit can be formed. For this reason, in the circuit board 1, it becomes possible to improve the freedom degree of circuit design.

  Next, the structure and manufacturing method of the circuit board 1 according to the second embodiment will be described with reference to FIGS. FIG. 5 is a cross-sectional view of the circuit board 1 according to the second embodiment. FIG. 6 is a perspective view showing one manufacturing process of the circuit board 1 of the second embodiment. FIG. 7 is a cross-sectional view showing one manufacturing process of the circuit board 1 of the second embodiment.

  In the second embodiment, as shown in FIG. 6A, a plurality of crosspieces 4t are formed at predetermined intervals on the inner peripheral surface of the through hole 4h of the metal core 4. As shown in FIG. 6B, in a state where the lower part 3b of the metal inlay 3 is fitted in the through hole 4h of the metal core 4, each crosspiece 4t is connected to the lower part 3b of the metal inlay 3 from the inner peripheral surface of the through hole 4h. It protrudes to the length which hangs on the outer peripheral surface.

  At the time of manufacturing the circuit board 1, first, as shown in FIG. 7A, the lower portion 3b of the metal inlay 3 is fitted into the through hole 4h of the metal core 4 installed on the horizontal reference plane A (FIG. 6). (B)). And each crosspiece 4t of the metal core 4 and the outer peripheral surface of the lower part 3b of the metal inlay 3 are fixed by welding. Thereby, the metal inlay 3 does not fall off from the through hole 4h of the metal core 4.

  Then, as described above, the gap between the lower portion 3 b of the metal inlay 3 and the metal core 4, the upper surface of the metal core 4, and the periphery of the metal inlay 3 are filled with the insulating base 2. Further, a circuit such as a wiring pattern is formed on the inside and the top surface of the insulating base 2 by printing to constitute the inner layers Lc and Lb and the surface layer La. Further, a mounting region R is provided on the upper surface of the insulating base 2 (FIG. 7B). Then, vias 6 a to 6 c are formed so as to penetrate predetermined wiring patterns 5 a to 5 e, 5 g and 5 s and the metal core 4 or the metal inlay 3. Further, the metal core 4 is cut to insulate the right part 4a and the left part 4b (FIG. 7C).

  Further, a predetermined crosspiece 4t of the metal core 4 is cut. In this example, as shown in FIG. 7D, the crosspiece 4 t provided on the right part 4 a side of the metal core 4 is cut to insulate the right part 4 a of the metal core 4 and the metal inlay 3. The cut portion is filled with the insulating substrate 2. The crosspiece 4t provided on the left part 4b side of the metal core 4 is not cut, and the left part 4b of the metal core 4 and the lower part 3b of the metal inlay 3 are kept connected. Thus, an electric circuit including the FET 7 to be mounted in the mounting region R is formed (FIG. 5).

  According to the second embodiment, since the lower part 3b of the metal inlay 3 and the metal core 4 are connected via the crosspiece 4t in one manufacturing process of the circuit board 1, the metal inlay 3 penetrates the metal core 4 in the subsequent manufacturing process. It is possible to prevent the holes 4h and the insulating substrate 2 from falling off. For this reason, it becomes easy to perform processes such as adhesion of the insulating base 2 and formation of the vias 6c, and the circuit board 1 can be manufactured more easily.

  Further, since the lower part 3b of the metal inlay 3 and the left part 4b of the metal core 4 are kept connected after the circuit board 1 is manufactured, the heat generated in the FET 7 mounted in the mounting region R is transmitted to the metal inlay 3. After that, it can be easily transmitted from the lower part 3 b of the metal inlay 3 to the left part 4 b of the metal core 4. And heat can be efficiently transmitted from the lower part 3b of the metal inlay 3 or the left part 4b of the metal core 4 to the heat sink 9 via the insulating heat radiating sheet 10, and heat can be dissipated from the heat sink 9 to the outside. Therefore, the heat dissipation of the circuit board 1 can be further improved.

  Next, the structure of the circuit board 1 ′ of the third embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 is a plan view of the circuit board 1 ′ of the third embodiment. FIG. 9 is a cross-sectional view of the circuit board 1 ′ of the third embodiment.

  In the third embodiment, as shown in FIG. 8, in order to cool a plurality (two) of FETs 7 at once, a metal inlay 3 'having a large area in plan view is used. Further, in order to insulate the FETs 7 from each other, as shown in FIG. 9, the insulating base 2 is laminated so as to fill the upper surface of the metal inlay 3 '. Three inner layers Ld, Lb, and Lc are provided inside the insulating base 2, and a surface layer La is provided on the upper surface of the insulating base 2.

  As shown in FIG. 8, the surface layer La is provided with a plurality (two) of mounting regions R for mounting a plurality of FETs 7. In addition, the surface layer La is provided with a plurality (two each) of wiring patterns 5s, 5g, and 5d 'for connecting the terminals 7d, 7g, and 7s of each FET 7. Among them, the body 7 a and the drain terminal 7 d of each FET 7 are connected to each wiring pattern 5 d ′ by solder 8. Each mounting region R is provided so as to cover a part of the upper surface of the insulating base 2 and the upper surfaces of the wiring patterns 5d ', 5g, and 5s.

  The metal inlay 3 ′ is provided at a position that overlaps each mounting region R in the vertical direction. As shown in FIG. 9, wiring patterns 5a, 5b, 5c, and 5e are provided in the inner layers Lb and Lc located on the side of the metal inlay 3 '. These wiring patterns 5a, 5b, 5c, and 5e are provided for each FET 7 and are independent of each other.

  Between the upper surface of the metal inlay 3 ′ and each mounting region R, the insulating base 2 and the inner layer Ld are interposed. The inner layer Ld is provided with wiring patterns 5h, 5i, 5j, and 5k made of copper foil. These wiring patterns 5h, 5i, 5j, and 5k are provided for each FET 7 and are independent of each other. Among them, the wiring patterns 5 i and 5 j are provided between the upper surface of the metal inlay 3 ′ and the mounting region R.

  Below the FET 7, the wiring pattern 5d 'in the mounting region R of the surface layer La and the wiring pattern 5j of the inner layer Ld are electrically connected by a plurality of vias 6d. Further, the wiring pattern 5s in the mounting region R of the surface layer La and the wiring pattern 5i of the inner layer Ld are electrically connected by the via 6e. The vias 6d and 6e are provided between the upper surface of the metal inlay 3 'and the mounting region R so as to penetrate the surface layer La and the inner layer Ld. The vias 6d and 6e are provided for each FET 7. The vias 6d and 6e are examples of the “second conductive portion” in the present invention.

  Further, the wiring pattern 5d 'on the surface layer La and the wiring pattern 5k on the inner layer Ld are electrically connected by the via 6f. The via 6f is provided so as to penetrate the surface layer La and the inner layer Ld.

  The right part 4a and the left part 4b of the metal core 4 are provided for each FET 7 and are insulated from each other. The vias 6a ', 6b, and 6c are provided for each FET 7.

  A plurality of (two) vias 6a ′ are provided so as to penetrate the wiring pattern 5s of the surface layer La, the wiring patterns 5h, 5a, and 5c of the inner layers Ld, Lb, and Lc, the insulating base 2, and the right portion 4a of the metal core 4. It has been. The via 6 a ′ conducts the wiring patterns 5 s, 5 h, 5 a, 5 c and the right part 4 a of the metal core 4. The vias 6a ', 6b, and 6c are examples of the "first conductive portion" in the present invention.

  A heat sink 9 is attached to the lower surface of the circuit board 1 ′ with screws 11. The lower surface of the metal inlay 3 ′ exposed from the lower surface of the insulating base 2 is in direct contact with the upper surface of the heat sink 9. An insulating heat radiation sheet 10 is provided between the lower surface of the metal core 4 exposed from the lower surface of the insulating base 2 and the upper surface of the heat sink 9.

  According to the third embodiment, when a plurality of mounting regions R are provided above one metal inlay 3 ′ and the FETs 7 are mounted in the mounting regions R, the FETs 7 are insulated from each other while the FETs 7 are insulated from each other. The generated heat can be transferred to the wiring patterns 5j and 5i of the inner layer Ld through the wiring patterns 5d ′ and 5s of the surface layer La and the vias 6d and 6e. Then, heat is transmitted from the wiring patterns 5j and 5i to the metal inlay 3 'having a large area, and then heat is transmitted from the lower part 3b of the metal inlay 3' to the heat sink 9, so that the heat is efficiently dissipated from the heat sink 9 to the outside. Can do. In other words, a plurality of FETs 7 can be cooled in a batch by a single metal inlay 3 ′ and a heat sink 9.

  Also, heat is transmitted from the wiring patterns 5j, 5i of the inner layer Ld and the metal inlay 3 'to the wiring patterns 5a to 5c, 5e of the other inner layers Lb, Lc and the metal core 4 through the insulating base 2, and the circuit board 1 Heat can be diffused throughout. Then, heat can be efficiently transferred from the metal core 4 having a large area to the heat sink 9 via the insulating heat-radiating sheet 10, and heat can be dissipated from the heat sink 9 to the outside.

  Further, the heat transferred from each FET 7 to the wiring patterns 5s, 5d ′ of the surface layer La via the terminals 7s, 7d, etc., is transmitted through the vias 6a ′, 6b, 6c, 6f to the wiring patterns 5a˜5 of the inner layers Ld, Lb, Lc. 5c, 5e, 5h, 5k and the metal core 4. Further, heat can be diffused from the wiring patterns 5a to 5c, 5d ', 5e, 5g to 5k, 5s and the metal core 4 through the insulating base 2 to the metal inlay 3' and the entire circuit board 1. Then, heat can be efficiently transmitted from the metal inlay 3 ′ or the metal core 4 to the heat sink 9 via the insulating heat dissipation sheet 10, and heat can be dissipated from the heat sink 9 to the outside.

  FIG. 10 is a cross-sectional view of a circuit board 1 ′ according to the fourth embodiment.

  In the fourth embodiment, the left part 4b of the metal core 4 and the lower part 3b of the metal inlay 3 'are connected. Specifically, as in the second embodiment described above, the crosspiece 4t is provided on the metal core 4, and the crosspiece 4t and the lower portion 3b of the metal inlay 3 'are connected by welding or the like. After that, the crosspiece 4t on the right part 4a side of the metal core 4 is cut to insulate the right part 4a from the metal inlay 3 '.

  In this way, after the heat generated in the FET 7 is transmitted to the metal inlay 3 ′, it can be easily transmitted from the lower part 3 b of the metal inlay 3 ′ to the left part 4 b of the metal core 4. Then, heat can be efficiently transmitted from the lower part 3b of the metal inlay 3 'and the left part 4b of the metal core 4 to the heat sink 9, and heat can be dissipated from the heat sink 9 to the outside.

  In the present invention, various embodiments other than those described above can be adopted. For example, in the above embodiment, the vias 6a to 6c are used as the first conduction parts that conduct the wiring patterns 5d, 5d ', 5s of the surface layer La of the circuit board 1, 1' and the metal inlays 3, 3 'or the metal core 4. Although an example in which 6a ′ is provided is shown, the present invention is not limited to this. In addition to this, for example, a copper terminal, a pin, a through hole, or the like may be provided as the first conductive portion, and the wiring pattern on the surface layer may be connected to the metal inlay or the metal core. Further, one of the metal inlay and the metal core and the wiring pattern on the surface layer may be electrically connected by the first conductive portion.

  Further, in the third embodiment shown in FIG. 9 and the like, vias are used as the second conduction parts that conduct the wiring patterns 5d ′ and 5s of the surface layer La in the mounting region R of the FET 7 and the wiring patterns 5j and 5i of the inner layer Ld. Although the example provided with 6d and 6e was shown, this invention is not limited only to this. In addition to this, for example, a copper terminal, a pin, a through hole, or the like may be provided as the second conductive portion to connect the surface layer wiring pattern and the inner layer wiring pattern in the mounting region.

  Moreover, in 2nd Embodiment shown in FIG. 5 etc., in order to fix the metal inlay 3 and the metal core 4, the example which formed the crosspiece 4t in the internal peripheral surface of the through-hole 4h of the metal core 4 was shown, The present invention is not limited to this. In addition to this, a crosspiece (not shown) is formed in the lower part 3b of the metal inlay 3, and the crosspiece and the inner peripheral surface of the through hole 4h of the metal core 4 are connected to connect the metal inlay 3 and the metal core 4 together. It may be fixed.

  Moreover, although the example which used the heat sink 9 was shown as a heat radiator in the above embodiment, this invention is not limited only to this, Other air-cooled type or water-cooled type heat radiators, or refrigerant | coolants You may use the radiator etc. which used. Moreover, you may use not only a metal radiator but the radiator formed with resin with high heat conductivity. In this case, it is not necessary to provide the insulating heat radiating sheet 10 between the radiator and the circuit board, and the insulating heat radiating sheet 10 can be omitted.

  Further, in the above embodiment, the example in which the present invention is applied to the multilayer circuit board 1, 1 ′ on which the FET 7 is mounted on the upper surface is given. The present invention can also be applied to a multilayer circuit board.

1, 1 'circuit board 2 insulating base 3, 3' metal inlay (first heat transfer member)
3a upper part 3b lower part 4 metal core (second heat transfer member)
4h Through-hole 4t Crosspiece 5d, 5g, 5s Surface layer wiring pattern 5a, 5b, 5c, 5e Inner layer wiring pattern 5i, 5j Inner layer wiring pattern 6a, 6a ′, 6b, 6c Via (first conductive portion)
6d, 6e Via (second conduction part)
7 FET (electronic parts)
9 Heat sink
10 Insulating heat dissipation sheet (third heat transfer member)
La surface layer Lb, Lc inner layer Ld inner layer R mounting area

Claims (7)

A heat generating electronic component mounting region and a wiring pattern are provided on the upper surface of the plate-like insulating base, and a first heat transfer member having a convex longitudinal section and a larger diameter from the upper part to the lower part is embedded in the insulating base, In the circuit board provided with the second heat transfer member in the shape of the lower surface of the insulating base,
The first heat transfer member is provided at a position overlapping the mounting region in the vertical direction,
The lower surface of the first heat transfer member is exposed from the lower surface of the insulating base,
And the lower the thickness of the first heat transfer member, the thickness of the second heat transfer member is made identical,
The insulating base is interposed between the upper surface of the first heat transfer member and the mounting region, and an inner layer inside the insulating base, a wiring pattern in the inner layer, and a second conductive portion are provided. Provided,
The circuit board characterized in that the second conduction portion conducts the wiring pattern between the upper surface of the first heat transfer member and the mounting area and the wiring pattern provided in the mounting area . The circuit board according to claim 1,
A first conduction part is provided so as to penetrate the lower part of the second heat transfer member or the first heat transfer member while penetrating the wiring pattern on the upper surface of the insulating base and the insulating base;
The circuit board characterized in that the first conduction portion conducts the wiring pattern on the upper surface of the insulating base and the second heat transfer member or the first heat transfer member. The circuit board according to claim 2,
A wiring pattern is provided on the surface layer on the upper surface of the insulating substrate and the inner layer on the inside,
The first conductive portion penetrates the lower portion of the second heat transfer member or the first heat transfer member while penetrating the wiring pattern of the surface layer, the wiring pattern of the inner layer, and the insulating base, A circuit board, wherein the wiring pattern, the wiring pattern of the inner layer, and the second heat transfer member or the first heat transfer member are electrically connected. The circuit board according to any one of claims 1 to 3,
The circuit board, wherein the lower part of the first heat transfer member and the second heat transfer member are connected. A heat dissipation structure for dissipating heat from the circuit board according to any one of claims 1 to 4 ,
A radiator is attached to the lower surface of the circuit board,
An insulating sheet-like third heat transfer member is provided between the upper surface of the radiator and the lower surface of the first heat transfer member or the lower surface of the second heat transfer member. Circuit board heat dissipation structure. A method for manufacturing a circuit board according to any one of claims 1 to 4 ,
A through hole having a diameter larger than the lower portion of the first heat transfer member is formed in the second heat transfer member,
The lower part of the first heat transfer member is inserted into the through hole,
The gap between the lower part of the first heat transfer member and the second heat transfer member, the upper surface of the second heat transfer member, and at least the periphery of the first heat transfer member are filled with the insulating base,
Then, the mounting area and the wiring pattern are formed on the upper surface of the insulating substrate. In the manufacturing method of the circuit board according to claim 6 ,
A plurality of crosspieces are formed between the inner peripheral surface of the through hole of the second heat transfer member or the lower portion of the first heat transfer member,
The lower portion of the first heat transfer member is fitted into the through hole, and the crosspieces are fixed to the inner peripheral surface of the through hole or the lower portion of the first heat transfer member,
The gap between the lower part of the first heat transfer member and the second heat transfer member, the upper surface of the second heat transfer member, and at least the periphery of the first heat transfer member are filled with the insulating base,
Then, the predetermined said crosspiece part is cut | disconnected, The manufacturing method of the circuit board characterized by the above-mentioned.

Images