WO2018168504A1

WO2018168504A1 - Component mounting body and electronic device

Info

Publication number: WO2018168504A1
Application number: PCT/JP2018/007847
Authority: WO
Inventors: 悠江口; 陽紀富田
Original assignee: Ｋｙｂ株式会社
Priority date: 2017-03-15
Filing date: 2018-03-01
Publication date: 2018-09-20
Also published as: JP6961902B2; JP2018152525A

Abstract

A component mounting body 100 according to an embodiment of the present invention comprises an electronic component 10 and a wiring board 20. The electronic component 10 has an obverse surface part 11 (first surface) having a heat dissipation terminal 110 (heat dissipation unit), and a reverse surface part 12 (second surface) having an electrode terminal 120. The wiring board 20 has a conductor pattern 22 and an insulator pattern 23. The conductor pattern 22 includes a first conductor part 221 extending in one axial direction across a mounting area of the electronic component 10, and is electrically connected to the electrode terminal 120. The insulator pattern 23 includes an opening 23a that faces opposite the electrode terminal 120 and is provided on the first conductor part 221, the insulator pattern 23 supporting both one-axial-direction end sides of the reverse surface part 12 of the electronic component 10.

Description

Component mounting body and electronic equipment

The present invention relates to a component mounting body having an exothermic electronic component and an electronic apparatus including the component mounting body.

Recently, as a control unit for electric power steering, an electronic control unit (ECU: Electronic Control Unit) including a power system board on which a power circuit is mounted and a control system board that generates a control signal is used. For example, the ECU generates a control signal for driving a motor for assisting the driver's steering force based on outputs from a steering torque sensor, a vehicle speed sensor, and the like of the steering wheel. As a component constituting the motor drive circuit, for example, a heat-generating switching element such as a power MOSFET is used. For this reason, the ECU is provided with a heat sink for efficiently radiating heat generated by the heat-generating electronic components.

For example, Patent Document 1 includes a printed circuit board on which a plurality of heating elements are mounted, and a metal case fixed to the printed circuit board through a plurality of screws, and the case is formed of silicon on the plurality of heating elements. An electronic control device is described which abuts via a heat conducting member of the system. Patent Document 2 describes a semiconductor device having a semiconductor layer, a connection electrode provided on one surface of the semiconductor layer, and a heat dissipation portion provided on the other surface of the semiconductor layer.

JP 2002-134970 A JP 2011-249430 A

With recent miniaturization of electronic equipment and high density mounting of components, improvement of heat dissipation characteristics for heat-generating electronic components is required. As a countermeasure, electronic components on a substrate as described in Patent Document 1 are required. A structure in which a heat sink such as a metal case is brought into contact with the upper surface of the substrate is widely used.

However, if the electronic component is mounted in an inclined position with respect to the substrate surface, the clearance between the electronic component and the heat sink will be widened, so the heat dissipation efficiency of the electronic component will be reduced, resulting in malfunction of the electronic device. May be incurred. Such a problem may occur due to the structure of the land portion on the substrate surface, the terminal layout of the electronic component, or both of them. Therefore, the structure of the land portion that can increase the parallelism of the electronic component to the substrate surface. Optimization is required.

In view of the circumstances as described above, an object of the present invention is to provide a component mounting body and an electronic apparatus that can increase the parallelism of an electronic component with respect to a substrate surface.

In order to achieve the above object, a component mounting body according to an embodiment of the present invention includes an electronic component and a wiring board.
The electronic component has a first surface having a heat radiating portion, and a second surface having an electrode terminal and opposite to the first surface.
The wiring board has a conductor pattern and an insulator pattern. The conductor pattern includes a first conductor portion extending across the mounting region of the electronic component in a uniaxial direction, and is electrically connected to the electrode terminal. The insulator pattern includes an opening provided on the first conductor portion and facing the electrode terminal, and supports both end sides in the uniaxial direction of the second surface.

In the component mounting body, the first conductor portion that is electrically connected to the terminal electrode of the electronic component is formed so as to extend across the component mounting region on the wiring board in the uniaxial direction, and Since the insulator pattern for supporting the electronic component is provided on the first conductor portion, the parallelism of the electronic component with respect to the substrate surface is increased. Thereby, the heat dissipation efficiency from the said electronic component to a heat sink improves, and it becomes possible to obtain the desired heat dissipation characteristic stably.

The electrode terminal is composed of a plurality of terminal parts including a first terminal part electrically connected to the first conductor part and a second terminal part parallel to the first terminal part, The conductor pattern may further include a second conductor portion that is electrically connected to the second terminal portion.
The second terminal portion may be composed of a single electrode or a plurality of electrodes.

Of the plurality of terminal portions, the first terminal portion may have the largest area.
Thereby, since the area | region which a 1st conductor part occupies becomes comparatively large, an electronic component is supported more stably.

An electronic device according to an aspect of the present invention includes the component mounting body, and a heat sink that is disposed to face the wiring board and is connected to the heat dissipation portion via a heat conductive member. Has a heat radiating terminal as the heat radiating portion.

It is a schematic sectional drawing of the principal part which shows the structure of the component mounting body which concerns on one Embodiment of this invention. It is the upper surface side perspective view and lower surface side perspective view which show roughly the whole structure of the electronic component in the said component mounting body. It is a schematic plan view of the principal part of the wiring board in the said component mounting body. It is a schematic plan view of the principal part of the wiring board which concerns on a comparative example. FIG. 5 is a schematic cross-sectional view in the YY line direction in FIG. 4. It is a principal part schematic plan view which shows the modification of a structure of the wiring board in the said component mounting body. It is a principal part schematic plan view which shows the other modification of the structure of the wiring board in the said component mounting body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a main part showing a configuration of a component mounting body 100 according to an embodiment of the present invention.
In the figure, the X axis, the Y axis, and the Z axis indicate three axial directions orthogonal to each other, and the Z axis corresponds to the thickness direction (height direction) of the component mounting body 100.

The component mounting body 100 of this embodiment includes an electronic component 10 and a wiring board 20 that supports the electronic component 10. The component mounting body 100 is configured as, for example, a power circuit board or a control circuit board of various electronic devices, and a plurality of circuit components are mounted on the wiring board 20 in addition to the electronic components 10, not shown.

The electronic component 10 is composed of a heat generating electronic component. Typically, such an electronic component includes a switching element such as a power MOSFET (Metal Oxide Semiconductor Semiconductor Field Field Effect Transistor). In addition, various electronic components such as an insulated gate bipolar transistor (IGBT: Insulated Gate Bipolar Transistor) and a thyristor can be used.

The electronic component 10 is surface-mounted on the wiring board 20 by a reflow soldering method. In the present embodiment, the component mounting body 100 further includes a heat sink 30 facing the wiring board 20 with the electronic component 10 interposed therebetween, as shown in FIG. The heat sink 30 is typically configured by a structure such as a metal plate or case, and radiates heat from the electronic component 10 by being thermally connected to the electronic component 10. The heat sink 30 may be fixed to the wiring board 20 or may be fixed to a casing (not shown) of an electronic device that supports the wiring board 20.

FIGS. 2A and 2B are a top perspective view and a bottom perspective view schematically showing the overall configuration of the electronic component 10.

As shown in the figure, the electronic component 10 is composed of a rectangular parallelepiped semiconductor package component. The size of the electronic component 10 is not particularly limited. For example, the electronic component 10 has a rectangular planar shape with a side length of 5 mm to 10 mm. The electronic component 10 has a front surface portion 11 (first surface) facing the heat sink 30 and a back surface portion 12 (second surface) on the opposite side (facing the wiring board 20). The front surface portion 11 and the back surface portion 12 are configured by a plane parallel to the XY plane. The front surface portion 11 is provided with a heat dissipation terminal 110 as a heat dissipation portion, and the back surface portion 12 is provided with an electrode terminal 120. Yes.

The heat radiating terminal 110 is thermally connected to the heat sink 30 via a heat conducting member 42 attached to the surface portion 11. For example, the heat conductive member 42 has insulating properties, and a resin material such as a heat conductive adhesive or a heat conductive adhesive sheet is employed. The heat radiating terminal 110 is constituted by a single terminal having a rectangular planar shape, and is disposed at a substantially central portion of the surface portion 11. Of course, the heat radiating terminal 110 is not limited to this example, and may be composed of a plurality of terminals arranged in a predetermined pattern on the surface portion 11. The heat dissipation of the electronic component 10 can be further improved by configuring the heat dissipation terminal 110 with a metal material having high heat dissipation.

The electrode terminal 120 corresponds to an external terminal of the electronic component 10 and is electrically connected to a land portion on the wiring board 20. In the present embodiment, the electrode terminal 120 includes a plurality of terminal portions including a first terminal portion 121 and a second terminal portion 122.

The first terminal portion 121 is composed of a single terminal having a rectangular planar shape, and is disposed at a substantially central portion of the back surface portion 12. On the other hand, the second terminal portion 122 is composed of a plurality of (four in this example) terminals having a rectangular planar shape, and is arranged along one side portion of the back surface portion 12 with an interval. Of the first terminal portion 121 and the second terminal portion 122, the first terminal portion 121 has the largest area, and extends from the substantially central portion of the back surface portion 12 to the peripheral portion on one side in the Y-axis direction. Occupies an area. The first terminal portion 121 and the second terminal portion 122 are arranged so as to face each other in the Y-axis direction on the back surface portion 12, and one end of each protrudes outward (side) from the back surface portion 12. Configured to do.

It should be noted that the shapes and layouts of the terminal portions 121 and 122 shown in the figure are examples, and it is needless to say that the terminal portions 121 and 122 can be appropriately changed according to the type and size of the parts.

The wiring board 20 is typically composed of a multilayer wiring board in which insulating bases made of synthetic resin or the like and conductor layers made of copper foil or the like are alternately laminated. One surface of the wiring board 20 is configured as a mounting surface 21 on which the electronic component 10 is mounted.

As shown in FIG. 1, the mounting surface 21 of the wiring board 20 has a conductor pattern 22 and an insulator pattern 23. The conductor pattern 22 is typically composed of a copper foil having a predetermined pattern shape formed on the surface of the insulating substrate 24. The insulator pattern 23 is typically composed of a solder resist having a predetermined thickness that covers the surfaces of the conductor pattern 22 and the insulating base 24.

FIG. 3 is a schematic plan view of a main part for explaining the configuration of the mounting surface 21.

As shown in FIG. 3, the conductor pattern 22 has a first conductor portion 221 and a second conductor portion 222. The first conductor portion 221 is electrically connected to the first terminal portion 121 (see FIGS. 1 and 2B) of the electronic component 10, and the second conductor portion 222 is the second terminal portion of the electronic component 10. 122 (see FIG. 2B) are electrically connected to each other.

The first conductor portion 221 is formed in a strip shape extending across the mounting area 20A of the electronic component 10 on the mounting surface 21 in the uniaxial direction (X-axis direction). The first conductor portion 221 has a width dimension that is equal to or greater than the length along the Y-axis direction of the first terminal portion 121, and a length dimension that crosses the first terminal portion 121 in the X-axis direction. The tip 221a is configured to be located outside the component mounting area 20A. On the other hand, the second conductor portions 222 are arranged in the X-axis direction at a predetermined interval so as to correspond to the respective second terminal portions 122.

The insulator pattern 23 covers the conductor pattern 22 and the insulating base 24 on the mounting surface 21 as described above, and is connected to the electrode terminal 120 (first and second terminal portions 121 and 122).

Openings

23a and 23b for forming 51 and 52 are provided. The

openings

23a and 23b are typically formed at predetermined positions on the mounting surface 21 by using a photolithography technique.

The opening 23 a is provided on the first conductor portion 221 facing the first terminal portion 121. The opening 23a has a substantially rectangular planar shape, and is formed with an area that is the same as or slightly larger than the land 51 (first terminal 121). In particular, in this embodiment, the length of the side along the Y-axis direction of the opening 23a is formed to be slightly larger than the width dimension along the Y-axis direction of the land portion 51 (first conductor portion 221). .

The opening 23b is provided on the end portion of the second conductor portion 222 facing each of the second terminal portions 122. The opening 23b has a substantially rectangular planar shape, and is formed with an area that is the same as or slightly larger than the land 52 (second terminal 122). In particular, in this embodiment, the length of the side along the X-axis direction of the opening 23b is slightly larger than the width dimension along the X-axis direction of the land portion 52 (second conductor portion 222). The length of the side of the opening 23b along the Y-axis direction is slightly larger than the length of the land 52 along the Y-axis direction.

The conductor pattern 22 (first and second conductor portions 221 and 222) is connected to the electrode terminals 120 (first and second electrodes) of the electronic component 10 via the conductive bonding material 41 filled in the

land portions

51 and 52. Terminal portions 121 and 122) (see FIG. 1). The bonding material 41 is typically a brazing material such as lead-free solder. The bonding material 41 is applied and filled in advance on the

land portions

51 and 52 by a screen printing method or the like, and then the electronic component 10 is mounted on a mounting surface 20A (see FIG. 2) on the mounting surface 21 through a mounting process, a reflow process, and the like. To be implemented). Thereby, the component mounting body 100 is produced. Note that the bonding material 41 is not limited to a solder material, and may be a conductive paste containing metal particles or an anisotropic conductive paste.

At this time, the

openings

23a and 23b of the insulator pattern 23 have a function of preventing the bonding material 41 from flowing out to regions other than the

land portions

51 and 52. That is, since the opening areas of the

openings

23a and 23b are limited, a sufficient amount of the bonding material 41 for bonding onto the

land portions

51 and 52 is secured. Moreover, since each opening

part

23a, 23b is individually formed corresponding to each

land part

51, 52, the short circuit between land parts is prevented.

Furthermore, the insulator pattern 23 is formed on the insulating substrate 24 and the conductor pattern 22 with a predetermined thickness by a printing method, a spin coating method, or the like, and the conductor pattern 22 is formed on the insulating substrate 24 with a predetermined thickness. Formed with. And the insulator pattern 23 is provided on each surface so that the level | step difference between the conductor pattern 22 and the insulation base material 24 may be followed. Therefore, the insulator pattern 23 includes a first area 231 (area shown by hatching and hatching in FIG. 3) covering the conductor pattern 22 and a second area 232 (area shown in FIG. 3) covering the insulating substrate 24. The first region 231 and the second region 232 typically have a height difference corresponding to the thickness of the conductor pattern 22.

In the component mounting body of the present embodiment, among the electrode terminals 120 of the electronic component 10, the first terminal portion 121 occupies the main area of the back surface portion 12 of the electronic component 10, and the mounting surface 21 of the wiring board 20 Of the provided conductor pattern 22, the first conductor portion 221 connected to the first terminal portion 121 is formed so as to straddle (or cross) the component mounting region 20A in one axis direction (X-axis direction in FIG. 3). ing. For this reason, as shown in FIG. 1 (corresponding to a cross-sectional view in the XX line direction in FIG. 3), the back surface portion 12 of the electronic component 10 extends in the uniaxial direction across the land portion 51 (opening portion 23a). It is supported by the first region 231 of the insulator pattern 23 covering one conductor portion 221. That is, both end sides in the X-axis direction of the back surface portion 12 of the electronic component 10 are supported by the first region 231 of the insulator pattern 23. As a result, the electronic component 10 can be mounted with high parallelism to the surface (mounting surface 21) of the wiring board 20.

On the other hand, as shown in FIG. 4, the first conductor portion 221 does not straddle the component mounting region 20A in the X-axis direction (does not cross), for example, the tip portion 221a is positioned within the region of the opening 23a. In the formed wiring board 200 according to the comparative example, the first region 231 of the insulator pattern 23 covering the first conductor portion 221 is unevenly distributed on one side (right side in FIG. 4) of the component mounting region 20A. become. As a result, the electronic components 10 mounted in the component mounting area 20A have different heights across the land portion 51 (opening 23a) as shown in FIG. 5 corresponding to the YY line direction cross section in FIG. Since it is supported by the first region 231 and the second region 232 of the insulator pattern 23, the posture is inclined obliquely with respect to the surface of the wiring substrate 200.

When the electronic component 10 is mounted in an inclined posture with respect to the surface of the wiring board 200, the surface portion 11 of the electronic component 10 is also inclined, so that the thickness of the heat conducting member 42 is made uniform by the inclination of the electronic component 10. The clearance between the heat sink 30 and the surface portion 11 cannot be reduced. For this reason, a uniform heat dissipation effect cannot be obtained in the plane of the surface portion 11, and there is a possibility of causing an operation failure of the electronic device. Such a problem becomes more prominent as the size of the electronic component 10 increases.

On the other hand, according to the present embodiment, the electronic component 10 is mounted with a high degree of parallelism with respect to the surface (mounting surface 21) of the wiring board 20, and therefore the surface portion 11 of the electronic component 10 and the heat sink 30 The clearance between them can be narrowed, and a uniform heat radiation effect can be stably obtained in the surface portion 11 without causing variations in heat transfer characteristics. Thereby, a high heat dissipation effect can be obtained for the electronic component 10 having a large amount of heat generation, and stable operation characteristics of the electronic device can be ensured.

Further, even when a plurality of heat-generating electronic components are mounted on the wiring board 20, each electronic component is desired for the wiring board 20 by configuring the component mounting area of each electronic component in the same manner as described above. Parallelism can be ensured. As a result, it is possible to achieve appropriate thermal connection with each electronic component with a single heat sink 30, and to obtain the desired heat dissipation characteristics of each electronic component.

As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, Of course, a various change can be added.

For example, in the above embodiment, the first terminal portion 121 of the electronic component 10 is configured as a part of the electrode terminal 120, but the first terminal portion 121 is similar to the heat dissipation terminal 110. It may have the function as.

Further, in the above embodiment, the second terminal portion 122 that constitutes the electrode terminal 120 of the electronic component 10 is constituted by a plurality of terminal portions. However, the present invention is not limited thereto, and the second terminal portion 122 may be constituted by a single terminal portion. Good. In this case, a single land portion 53 is formed through the opening 23c in the second conductor portion 223 connected to the terminal portion as in the wiring board 210 shown in FIG.

Similarly, the first terminal portion 121 constituting the electrode terminal 120 of the electronic component 10 may be composed of a plurality of terminal portions. In this case, like the wiring board 220 shown in FIG. 7, a plurality of conductor portions 224 connected to the terminal portion are also configured, and each conductor portion 224 has a plurality of land portions 54 via openings 23d. Is formed. And since each conductor part 224 is formed so that component mounting area | region 20A may be straddled to a uniaxial direction, it becomes possible to support the back surface part of the electronic component 10 in parallel with respect to a board | substrate surface.

Claims

An electronic component having a first surface having a heat dissipating part and a second surface having an electrode terminal opposite to the first surface;
A conductive pattern electrically connected to the electrode terminal including the first conductor portion extending across the mounting area of the electronic component in a uniaxial direction; and the electrode terminal provided on the first conductor portion And a wiring board having an insulating pattern that supports both end sides in the uniaxial direction of the second surface.
The component mounting body according to claim 1,
The electrode terminal is composed of a plurality of terminal parts including a first terminal part electrically connected to the first conductor part and a second terminal part parallel to the first terminal part,
Of the plurality of terminal portions, the first terminal portion has the largest area,
The conductor pattern further includes a second conductor portion that is electrically connected to the second terminal portion.
The component mounting body according to claim 1;
A heat sink disposed opposite to the wiring board and connected via the heat dissipating part and a heat conducting member,
The electronic component is an electronic device having a heat dissipation terminal as the heat dissipation portion.