JP2016171202A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device capable of achieving both insulation and heat radiation of a heater element.SOLUTION: An electronic device 100 is configured to comprise: a circuit board 10; a heater element 20 mounted on the circuit board 10; and a heat radiation substrate 30 that is a member for radiating heat generated from the heater element 20, and that is electrically and mechanically connected with an electrode of the heater element 20. The heat radiation substrate 30 includes: a plurality of laminated resin layers; an opposed side conductor exposed to a surface of the plurality of resin layers and connected with the electrode of the heater element 20; and an opposite side conductor exposed to a surface at an opposite side to the opposed side conductor. The opposite side conductor is electrically insulated from the opposed side conductor by a third resin layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic device in which a heating element is mounted on a circuit board.

  Conventionally, as an example of the electronic apparatus, there is an electronic component module disclosed in Patent Document 1. The electronic component module includes a substrate, a plurality of external terminals provided on the first surface of the substrate, and a semiconductor chip (hereinafter referred to as a heating element) provided in a region surrounded by the plurality of external terminals. . The electronic component module is mounted on a mounting board.

  The mounting substrate is provided with a heat radiating via that penetrates itself and a heat diffusion pattern connected on the heat radiating via. The electronic component module is mounted on the mounting board with the back surface of the heat generating element connected to the heat diffusion pattern.

International Publication No. 2014/20787

  Incidentally, some heating elements have electrodes formed on the back surface. In such a case, in the electronic device in which the electronic component module is mounted on the mounting substrate, the electrode of the heating element is connected to the thermal diffusion pattern. In the electronic device, a thermal diffusion pattern is connected to a heat dissipation via that penetrates the mounting substrate. Therefore, the electronic device can dissipate the heat generated from the heating element from the heat diffusion pattern through the heat dissipation via.

  However, in the electronic device, the heat radiating via connected to the electrode of the heat generating element through the thermal diffusion pattern penetrates the mounting substrate. For this reason, in the electronic device, the electrode of the heating element is not insulated from the outside. Therefore, the electronic component module has a problem that heat dissipation and insulation of the heating element are not compatible.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an electronic device that can achieve both insulation and heat dissipation of a heating element.

In order to achieve the above object, the present invention provides:
A circuit board (10);
A heating element (20) mounted on a circuit board and having an electrode formed on the opposite side of the surface facing the circuit board, and generating heat by operation;
A member that dissipates heat generated from the heating element, and includes a heat dissipating substrate (30, 30a, 30b) electrically and mechanically connected to the electrode,
The heat dissipation board is
A plurality of laminated resin layers (311, 321, 331);
An opposing conductor (322) exposed on the surface of the plurality of resin layers facing the heating element and connected to the electrode;
An opposite conductor (332) exposed on the surface opposite to the opposite conductor in the plurality of resin layers,
The opposite conductor is electrically insulated from the opposite conductor by a part of the plurality of resin layers.

  As described above, the present invention includes a circuit board, a heating element mounted on the circuit board, and a heat dissipation board that dissipates heat generated from the heating element. The heat dissipation substrate is provided with a plurality of laminated resin layers and opposing and opposite conductors exposed on both surfaces of the plurality of resin layers. In the present invention, the opposing conductor is connected to the electrode of the heating element, and the opposite conductor is electrically insulated from the opposing conductor by a part of the plurality of resin layers.

  For this reason, this invention can radiate the heat | fever emitted from the heat generating element through a part of resin layer and the opposite conductor from the opposing conductor. Furthermore, according to the present invention, since the opposing conductor and the opposite conductor to which the electrode of the heating element is connected are electrically insulated by a part of the resin layer, the electrode of the heating element can be insulated from the outside. Thus, the present invention can achieve both insulation and heat dissipation of the heating element.

  The reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later as one aspect, and the technical scope of the invention is as follows. It is not limited.

It is sectional drawing which shows schematic structure of the electronic device in embodiment. It is a top view which shows schematic structure of the electronic device in embodiment. It is sectional drawing which shows schematic structure of the thermal radiation board | substrate in embodiment. It is sectional drawing which shows schematic structure of the circuit board in embodiment. It is sectional drawing which shows the thermal radiation board | substrate with which the heat generating element in embodiment was mounted. 10 is a cross-sectional view illustrating a schematic configuration of an electronic device according to Modification 1. FIG. 10 is a cross-sectional view illustrating a schematic configuration of an electronic device according to Modification 2. FIG. 14 is a cross-sectional view illustrating a schematic configuration of an electronic device according to Modification 3. FIG. 10 is a cross-sectional view illustrating a schematic configuration of a heat dissipation board in Modification 3. FIG.

  Hereinafter, a plurality of embodiments for carrying out the invention will be described with reference to the drawings. In each embodiment, portions corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals and redundant description may be omitted. In each embodiment, when only a part of the configuration is described, the other configurations described above can be applied to other portions of the configuration.

  As shown in FIG. 1, the electronic device 100 includes a circuit board 10, a heating element 20 mounted on the circuit board 10, and a heat dissipation board 30 that radiates heat generated from the heating element 20. ing. The electronic device 100 is applied to, for example, an electronic control device mounted on an automobile.

  The circuit board 10 has one surface and an opposite surface, and the heating element 20 is mounted on the one surface. Therefore, one surface of the circuit board 10 can be rephrased as a mounting surface. Further, the circuit board 10 may be mounted with electronic components such as the heating element 20 and other circuit elements on the opposite surface.

  The circuit board 10 is formed with an insulating base material 11 and a wiring in which a plurality of insulating layers are laminated. As the insulating base material 11, an insulating resin such as an epoxy resin or a material mainly composed of ceramics can be used.

  In the circuit board 10, an inner layer wiring 12, a surface layer wiring 13, and a land 15 are formed as part of the wiring. The inner layer wiring 12 is laminated via the insulating base material 11. The surface layer wiring 13 is plating formed on the surface of a through hole provided in the insulating base material 11. The land 15 is formed on one surface and the opposite surface of the insulating base material 11. As the inner layer wiring 12, the surface layer wiring 13, and the land 15, a main component of a metal such as copper can be adopted.

  The circuit board 10 has an embedded resin 14 embedded in the through hole. The circuit board 10 is formed with a solder resist 16 covering the edge of the land 15 so that a part of the land 15 is exposed.

  The heating element 20 is a circuit element that generates heat when operated. As the heating element 20, for example, a semiconductor element such as a power transistor or IGBT can be adopted. The heating element 20 has an electrode formed on the surface opposite to the surface facing the circuit board 10. The heating element 20 may be in a bare chip state or a package state.

  The heating element 20 may have an electrode formed on the surface facing the circuit board 10. In the present embodiment, an example is adopted in which the electrode on the opposite surface side of the heating element 20 is mounted on the circuit board 10 via a bonding material. More specifically, the electrode on the opposite surface side of the heating element 20 is electrically and mechanically connected to the land 15 of the circuit board 10 via a bonding material. As the bonding material, a conductive bonding member such as solder or silver paste can be applied.

  The heat dissipation board 30 is electrically and mechanically connected to the electrodes of the heating element 20. Further, as shown in FIG. 2, the electronic device 100 only needs to be provided with a heat dissipation substrate 30 so as to face the heat generating element 20. That is, the heat dissipation substrate 30 may be provided on the heating element 20. In other words, the electronic device 100 does not need to be provided with the heat dissipation substrate 30 so as to face the entire mounting surface of the circuit board 10. Therefore, the electronic device 100 can suppress an increase in its physique.

  As shown in FIG. 3, the heat dissipation substrate 30 includes a core layer 31, a first buildup layer 32, and a second buildup layer 33. Thus, in the present embodiment, the build-up substrate is employed as the heat dissipation substrate 30.

  The core layer 31 includes a first resin layer 311, an inner layer conductor 312, and a plating part 313. The first resin layer 311 is an electrically insulating resin layer composed mainly of an epoxy resin or the like. The first resin layer 311 is one of the resin layers in the claims. The inner layer conductor 312 is formed with a metal such as copper as a main component, and is formed on both surfaces of the first resin layer 311. The inner layer conductor 312 has, for example, a flat plate shape.

  The plating part 313 is formed mainly of a metal such as copper, and penetrates the first resin layer 311 to connect both inner layer conductors 312. The plating portion 313 corresponds to the first interlayer connection portion 313 in the claims. Reference numeral 314 denotes a filling portion 314 embedded in the through hole of the first resin layer 311. It can be said that the filling portion 314 is an embedded resin portion.

  The first buildup layer 32 includes a second resin layer 321, an opposing conductor 322, and a laser via 323. The first buildup layer 32 is laminated on the heating element 20 side of the core layer 31. The second resin layer 321 is an electrically insulating resin layer composed mainly of an epoxy resin or the like. The second resin layer 321 is one of the resin layers in the claims.

  The opposing conductor 322 is formed with a metal such as copper as a main component, and is formed on the surface of the second resin layer 321 so as to face one of the two inner conductors 312. The opposing conductor 322 is a part that is electrically and mechanically connected to the electrode of the heating element 20. The opposing conductor 322 has, for example, a flat plate shape. In addition, the opposing conductor 322 has a rectangular shape facing the electrode of the heating element 20 and is connected to the entire area of the opposing surface of the electrode of the heating element 20 facing the opposing conductor 322.

  The laser via 323 is formed with a metal such as copper as a main component, and is embedded in the second resin layer 321. The laser via 323 connects the opposing conductor 322 and the inner layer conductor 312 facing the opposing conductor 322. The laser via 323 corresponds to the second interlayer connection portion in the claims. In addition, it is preferable to provide a plurality of laser vias 323 in a concentrated manner in a region facing the electrode of the heating element 20 because heat dissipation can be improved.

  The second buildup layer 33 includes a third resin layer 331 and an opposite conductor 332. The second buildup layer 33 is laminated on the opposite side of the core layer 31 from the heating element. The third resin layer 331 is an electrically insulating resin layer composed mainly of an epoxy resin or the like. The third resin layer 331 is one of a plurality of resin layers in the claims. The opposite conductor 332 is disposed opposite the other inner layer conductor 312 with the third resin layer 331 interposed therebetween. The opposite conductor 332 is exposed to the outside of the third resin layer 331. Further, it can be said that the opposite conductor 332 is a main heat dissipation part in the heat dissipation substrate 30. The opposite conductor 332 has, for example, a flat plate shape.

  The heat dissipation board 30 can be manufactured by a known build-up board manufacturing method. Therefore, the second resin layer 321 and the third resin layer 331 can be formed with a thickness of 100 μm or less. For example, the buildup layer can be formed with a thickness of about 60 μm.

  In addition, the board | substrate 10 described in Unexamined-Japanese-Patent No. 2014-82474 by the present applicant can be employ | adopted for the thermal radiation board | substrate 30. FIG. Therefore, refer to Unexamined-Japanese-Patent No. 2014-82474 regarding the structure and manufacturing method of the thermal radiation board | substrate 30. FIG.

  The heat dissipation substrate 30 is only an example of the present invention. That is, the present invention is not limited to this. The present invention relates to a plurality of laminated resin layers, a counter-side conductor exposed on the surface of the plurality of resin layers facing the heating element 20 and connected to an electrode of the heating element 20, and a counter-side conductor of the plurality of resin layers. Any heat dissipating substrate including the opposite conductor exposed on the opposite surface may be employed. And this invention can achieve the objective, if the opposite side conductor of a thermal radiation board | substrate is electrically insulated from the opposing side conductor by some resin layers. Therefore, the heat dissipation substrate of the present invention can be employed even if it is a resin substrate manufactured by a batch hot press known as PALAP. PALAP is a registered trademark.

  Here, a method for manufacturing the electronic device 100 will be described. First, in this manufacturing method, a circuit board 10 is prepared as shown in FIG. The circuit board 10 can be manufactured by a known manufacturing method. Next, in the present manufacturing method, the heating element 20 is mounted on the heat dissipation substrate 30 as shown in FIG. That is, in this manufacturing method, the electrode of the heat generating element 20 and the opposing conductor 322 of the heat dissipation board 30 are electrically and mechanically connected. Thereafter, in the manufacturing method, the heating element 20 to which the heat dissipation substrate 30 is connected is mounted on the circuit board. Thus, the manufacturing method can manufacture the electronic device 100.

  As described above, the electronic device 100 includes the circuit board 10, the heating element 20 mounted on the circuit board 10, and the heat dissipation board 30 that radiates the heat generated from the heating element 20. The heat dissipation substrate 30 is provided with a plurality of laminated resin layers 311, 321, 331, and opposite-side conductors 322 and opposite-side conductors 332 exposed on both surfaces of the plurality of resin layers 311, 321, 331. In the electronic device 100, the opposing conductor 322 is connected to the electrode of the heating element 20, and the opposite conductor 332 is electrically insulated from the opposing conductor 322 by the third resin layer 331.

  For this reason, the electronic device 100 can radiate the heat generated from the heating element 20 from the opposing conductor 322 via the third resin layer 331 and the opposite conductor 332. Further, in the electronic device 100, since the opposing conductor 322 to which the electrode of the heating element 20 is connected and the opposite conductor 332 are electrically insulated by the third resin layer 331, the electrode of the heating element 20 is connected to the outside. Can be insulated. Thus, the electronic device 100 can achieve both insulation and heat dissipation of the heating element 20.

  In other words, in the electronic device 100, the third resin layer 331, which is a buildup layer of about 60 to 100 μm, electrically connects the portion of the heat dissipation substrate 30 that is electrically connected to the opposing conductor 322 and the opposite conductor 332. Can be electrically insulated. Therefore, the electronic device 100 can easily transfer the heat transmitted from the heat generating element 20 to the portion electrically connected to the opposing conductor 322 in the heat dissipation substrate 30 to the opposite conductor 332. For this reason, the electronic device 100 can achieve both insulation and heat dissipation of the heating element 20.

  Furthermore, since the electronic device 100 includes the heat dissipation board 30, it is not necessary to provide a heat dissipation path in the circuit board 10. In this case, the electronic device 100 does not need to change the wiring routing in the circuit board 10 in order to secure the heat dissipation path. In other words, the circuit board 10 does not need to be routed in consideration of the heat dissipation path. Therefore, the electronic device 100 can reduce costs more than the case where the circuit board 10 is provided with a heat dissipation path.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. Below, the modifications 1-3 of this invention are demonstrated. The above-described embodiment and Modifications 1 to 3 can be implemented independently, but can be implemented in appropriate combination. The present invention is not limited to the combinations shown in the embodiments, and can be implemented by various combinations.

(Modification 1)
As shown in FIG. 6, the electronic device 110 of Modification 1 is different from the electronic device 100 in that a mold resin 40 is formed.

  In the electronic device 110, the mold resin 40 is provided on the mounting surface of the circuit board 10. The mold resin 40 is sealed in a state of being in close contact with the mounting surface of the circuit board 10, the heating element 20, and a part of the heat dissipation board 30. In other words, the mold resin 40 covers the mounting surface of the circuit board 10, the heat generating element 20, and a part of the heat dissipation board 30. The mold resin 40 seals the mounting surface of the circuit board 10 with the opposite conductor 332 of the heat dissipation board 30 exposed. Further, the mold resin 40 is in close contact with and sealed at a joint portion between the circuit board 10 and the heat generating element 20, a joint portion between the heat generating element 20 and the heat dissipation substrate 30, and the like.

  The electronic device 110 can achieve the same effect as the electronic device 100. Furthermore, since the electronic device 110 includes the mold resin 40, the heat generating element 20 and the like can be protected, and the junction between the circuit board 10 and the heat generating element 20 and the heat generating element 20 and the heat dissipation substrate 30 can be protected from the electronic device 100. It is possible to extend the life of the joint. The mold resin 40 can also be provided in the electronic device 120 of Modification 2 and the electronic device 130 of Modification 3 described later.

(Modification 2)
As shown in FIG. 7, the electronic device 120 of Modification 2 is different from the electronic device 100 in the configuration of the heat dissipation board 30 a and the connection structure of the heat dissipation board 30 a and the circuit board 10.

  The heat dissipation board 30 a has a connection land 34 a that is electrically connected to the opposing conductor 322 at a position facing the circuit board 10. The connection land 34 a is electrically connected to the opposing conductor 322 via, for example, the inner layer conductor 312 and the laser via 323.

  In the heat dissipation board 30 a, the connection land 34 a is electrically connected to the land 15 which is a part of the wiring of the circuit board 10 via the conductive solder 50. Thus, in the electronic device 120, the heat dissipation board 30 a and the circuit board 10 are connected via the connection land 34 a and the solder 50. The solder 50 corresponds to the connecting member in the claims. The electronic device 120 can employ a silver paste or the like instead of the solder 50.

  In the electronic device 120, a terminal 60 may be provided between the land 15 and the solder 50 as illustrated in FIG. 7. That is, the electronic device 120 may include the terminal 60 in order to connect the connection land 34a and the land 15 without increasing the thickness of the solder 50. In other words, the electronic device 120 includes the terminal 60 so that the connection land 34 a and the land 15 can be reliably connected by the solder 50. Therefore, the thickness of the terminal 60 is a thickness obtained by subtracting the thickness of the solder 50 from the thickness of the heating element 20. Thus, the electronic device 120 can mechanically connect the connection land 34 a and the land 15 with the solder 50 while suppressing the thickness of the solder 50.

  The electronic device 120 can achieve the same effect as the electronic device 100. Furthermore, in the electronic device 120, an extraction portion for electrically connecting the electrode of the heating element 20 and an external device of the electronic device 120 can be formed on the circuit board 10.

(Modification 3)
As shown in FIG. 8, the electronic device 130 of Modification 3 is different from the electronic device 100 in the configuration of the heat dissipation board 30 b and the connection structure of the heat dissipation board 30 b and the circuit board 10.

  A plurality of heating elements 20 are mounted on the circuit board 10. On the other hand, the heat dissipation substrate 30b is provided with a plurality of opposing conductors 322 that individually face each heating element 20. As shown in FIG. 9, the opposing conductors 322 are insulated from each other by the first resin layer 311, the second resin layer 321, and the third resin layer 331.

  On the other hand, the opposite conductor 332 is electrically insulated from each opposing conductor 322 by the third resin layer 331. For this reason, it is sufficient that one opposite conductor 332 is provided for the plurality of heating elements 20. That is, the opposite conductor 332 is provided so as to cover the entire area of the projection region of the plurality of opposite conductors 322 onto the opposite conductor 332.

  The electronic device 130 can achieve the same effect as the electronic device 100. Further, the electronic device 130 can collectively radiate heat while insulating the plurality of heating elements 20 from each other.

  DESCRIPTION OF SYMBOLS 10 Circuit board, 11 Resin base material, 12 Inner layer wiring, 13 Surface layer wiring, 14 Embedded resin, 15 Land, 16 Solder resist, 20 Heat generating element, 30 Heat dissipation board, 31 Core layer, 311 1st resin layer, 312 Inner layer conductor, 313 Plating part, 314 Filling part, 32 1st buildup layer, 321 2nd resin layer, 322 Opposite side conductor, 323 Laser via, 33 2nd buildup layer, 331 3rd resin layer, 332 Opposite side conductor, 100-130 Electronic equipment

Claims (4)

A circuit board (10);
A heating element (20) mounted on the circuit board and having an electrode formed on the opposite side of the surface facing the circuit board, and generating heat by operation;
A member that dissipates heat generated from the heating element, and includes a heat dissipation substrate (30, 30a, 30b) electrically and mechanically connected to the electrode,
The heat dissipation substrate is
A plurality of laminated resin layers (311, 321, 331);
A facing conductor (322) exposed on the surface of the plurality of resin layers facing the heating element and connected to the electrode;
An opposite conductor (332) exposed on a surface opposite to the opposite conductor in the plurality of resin layers,
The electronic device, wherein the opposite conductor is electrically insulated from the opposite conductor by a part of the plurality of resin layers. The heat dissipation board (30a) has a connection land (34a) electrically connected to the opposing conductor at a position facing the circuit board,
The electronic device according to claim 1, wherein the connection land is electrically connected to a part of the wiring of the circuit board via a conductive connection member. The circuit board is mounted with a plurality of the heating elements,
3. The electronic device according to claim 1, wherein the heat radiating substrate is provided with a plurality of the opposing conductors individually facing the heat generating elements. 4. The heat dissipation substrate is
A core layer (31), a first buildup layer (32) stacked on the heating element side of the core layer, and a second buildup layer (stacked on the opposite side of the core layer to the heating element) ( 33), and
The core layer penetrates the first resin layer (311), which is one of the resin layers, inner layer conductors (312) formed on both surfaces of the first resin layer, and the first resin layer. And a first interlayer connection portion (313) formed of a conductor connecting both inner layer conductors,
The first buildup layer includes a second resin layer (321), which is one of the plurality of resin layers, and the facing formed on the surface of the second resin layer so as to face one of the inner layer conductors. A side conductor (322) and a second interlayer connection part (323) formed of a conductor embedded in the second resin layer and connecting the inner layer conductor facing the opposing side conductor; Including
The second buildup layer is arranged to face the other of the inner conductors through the third resin layer (331) which is one of the plurality of resin layers and the third resin layer. The electronic device according to claim 1, further comprising an opposite conductor (332).

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