JP4582491B2 - Metal substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal substrate that is incorporated in a thin module power supply device that is particularly suitable for flowing a large current.
[0002]
[Problems to be solved by the invention]
In general, this type of metal substrate is applied particularly to a thin module power supply device incorporating a DC-DC converter. FIG. 3 shows a cross-sectional view of a so-called single-layer metal substrate 4. In FIG. 3, reference numeral 1 denotes a metal base such as aluminum having a heat dissipation effect, and an insulating layer 2 is provided on the surface of the metal base 1. In addition, a desired metal substrate 4 is formed by providing the conductor pattern 3 by printed wiring processing.
[0003]
In such a metal substrate 4, if a thick copper foil having a thickness of 70 μm or more is used as the conductive pattern 3 in response to an increase in current of the power supply device, the dimensional accuracy of pattern formation by etching deteriorates. There is no choice but to design small widths and wide intervals between the conductive patterns 3 and 3. For this reason, if a thick copper foil corresponding to a large current is used as the conductive pattern 3, even in a control circuit portion including other ICs mounted on the surface of the metal substrate 4, a design rule with a wide pattern interval is followed. Therefore, it is difficult to increase the density of the mounted components (miniaturization of the conductive pattern). In particular, in the case of a single metal substrate 4, the distance between the metal base 1 having a large surface area and the conductive pattern 3 is extremely short, so that the stray capacitance existing between the metal base 1 and the conductive pattern 3 is large. There is also a problem that it is susceptible to noise.
[0004]
In order to improve such a problem, a two-layer metal substrate 16 shown in FIG. 4 has been proposed. In the figure, a first insulating layer 12 is formed on the surface of the metal base 1, and a first conductor pattern 13 is provided on the surface of the first insulating layer 12. Furthermore, another second insulating layer 14 is formed on the surfaces of the flush first insulating layer 12 and the first conductor pattern 13, and another second conductor pattern 15 is provided on the surface of the second insulating layer 14. It is done. That is, a two-layer pattern portion in which the conductor patterns 13 and 15 are formed on both surfaces of the second insulating layer 14 is provided on the entire surface of the first insulating layer 12.
[0005]
The metal substrate 16 thus obtained can achieve a higher density of surface-mounted components by the amount of the conductive patterns 13 and 15 provided in two layers. Further, by using the first conductor pattern 13 as a shield, the stray capacitance existing between the metal base 1 and the second conductive pattern 15 can be reduced, and the influence of noise can be reduced. However, since the first insulating layer 12 and the first conductor pattern 13 are further interposed as compared with the single metal substrate 4 shown in FIG. 3, the metal base 1 and the second conductor pattern 15 on both sides of the metal substrate 16 are interposed. The heat resistance between the metal base 1 and the metal base 1 cannot be effectively utilized. Therefore, when the metal substrate 16 is used as a power supply device, there is a problem that it is not suitable for increasing the power and capacity of the device.
[0006]
In order to compensate for the drawbacks of the metal substrates 4 and 16, a partial double-layer metal substrate 28 shown in FIG. 5 is proposed. This metal substrate 28 has a two-layer pattern portion 29 in which the first conductor pattern 13 and the second conductor pattern 15 are provided on both surfaces of the second insulating layer 14 on the surface of the first conductor pattern 13 on the metal base 1. While being partially provided, the third conductive pattern 31 is provided on the first insulating layer 12 of the recess 30 where the two-layer pattern portion 29 is not provided. Thereby, on one metal base 1, the two-layer pattern part 29 in which the first conductor pattern 13 and the second conductor pattern 15 are partially laminated, and the single-layer pattern part 32 having only one conductor pattern 31 are formed. Are formed respectively.
[0007]
In the case of such a metal substrate 28, if an electronic component that generates a large amount of heat is mounted on the third conductor pattern 31 constituting the single-layer pattern portion 32, the first insulation is provided between the third conductor pattern 31 and the metal base 1. Since only the layer 12 is interposed, the thermal resistance is small, and heat can be quickly transferred to the metal base 1. Further, in the other two-layer pattern portion 29, the density of the surface-mounted components can be achieved as described above, and the influence of noise can be reduced by using the first conductor pattern 13 as a shield.
[0008]
However, since the heights of the second conductor pattern 15 and the third conductor pattern 31 are not uniform, there is a problem that it is impossible to perform printing of solder paste with a solder mask and mounting of surface mount components at a time. Even if the conductor patterns 13 and 15 are multi-layered, the minimum width of the conductor patterns 13 and 15 and the interval between the first conductor patterns 13 and 13 or the second conductor patterns 15 and 15 correspond to an increase in current. Therefore, there was a limit to increasing the density of surface mount components.
[0009]
Therefore, in view of the above problems, the present invention provides a metal substrate that can perform solder paste printing and electronic component mounting at a time without degrading heat dissipation characteristics, and that can increase the density of mounted components. Its purpose is to provide.
[0010]
[Means for Solving the Problems]
In the metal substrate according to the present invention, the first insulating layer is provided on the surface of the metal base, and the conductor pattern is provided on the surface of the first insulating layer. The multilayer pattern portion is partially provided on the surface of the first insulating layer, and a metal bus bar is provided in the recess not provided with the multilayer pattern portion, so that the surface of the metal bus bar and the surface of the conductive pattern are flush with each other. It is a thing.
[0011]
In this way, since the conductor pattern is provided in a plurality of layers at the location to be the multilayer pattern portion, it is possible to achieve a higher density of the surface mount component. In addition, since the conductor pattern and the surface of the metal bus bar to be connected to the surface-mounted component are formed on the same surface without unevenness, printing of solder paste with a solder mask and mounting of the component on a metal substrate are possible. It can be done at once. Also, by arranging the metal bus bar separately from the conductor pattern, a large current can be easily passed through the metal bus bar without being forced to design a pattern corresponding to a large current.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
In FIGS. 1 and 2 showing an embodiment of the present invention, reference numeral 40 denotes a plate-like metal base that is substantially rectangular as a base material of the metal substrate 41. This is the same as the conventional example, For example, it is formed of aluminum or the like which is a metal member having excellent thermal conductivity.
Reference numeral 42 denotes a first insulating layer provided so as to cover the entire surface of the metal base 40. On the surface of the first insulating layer 42, a two-layer pattern portion 46 corresponding to a multilayer pattern portion in which the first conductor pattern 44 and the second conductor pattern 45 are respectively provided on both surfaces of the second insulating layer 43 is partially provided. . The two-layer pattern portion 46 is provided so that the first insulating layer 42 faces the first conductor pattern 44. For example, an insulating sheet is provided between the first insulating layer 42 and the two-layer pattern portion 46. Another insulator 48 is interposed.
[0014]
A third conductor pattern 52 is exposed and provided on the first insulating layer 42 in the recess 51 of the metal substrate 40 where the two-layer pattern portion 46 is not provided. The third conductor pattern 52 is also provided at the position of the two-layer pattern portion 46. By providing a plated through hole (not shown) in the two-layer pattern portion 46, electrical connection between the conductor patterns 44, 45, and 52 is achieved. Are mutually aimed at. A flat metal bus bar 53 having excellent conductivity and suitable for flowing a large current is connected and fixed to the surface of the third conductor pattern 52 by soldering or the like. In particular, in this embodiment, the surface of the metal bus bar 53 having a substantially flat shape and the second insulation are considered in consideration of printing of solder paste with a solder mask of the metal substrate 40 and mounting of an electronic component 61 to be described later. The surface of the layer 43 is formed on the same plane, that is, flush.
[0015]
61 is an electronic component that is a component of the power supply device, and a plurality of electronic components are mounted on the surface of the metal substrate 40 where the second conductor pattern 45 and the metal bus bar 53 are exposed. As is well known, each electronic component 61 includes a component main body 62 and a conductive lead terminal 63 extending therefrom, and the rear surface of the component main body 62 and the lead terminal 63 are formed with the same second conductor pattern 45 and the like. The metal bus bar 53 is fixedly connected to the surface of the metal bus bar 53 by soldering or the like.
[0016]
When manufacturing the metal substrate 40 having the above-described configuration, the first insulating layer 42 is attached so as to cover the entire surface of the metal base 41, and the third conductor pattern 52 is printed on the surface of the first insulating layer 42. . On the other hand, the first conductor pattern 44 and the second conductor pattern 45 are printed on both surfaces of the second insulating layer 43, respectively, and the second insulating layer 43 with the conductor patterns 44 and 45 to be the two-layer pattern portion 46 is insulated. Affixed to the surface of the first insulating layer 42 with the body 48 interposed. Here, since the third conductor pattern 52 is exposed on the bottom surface of the recess 51 of the metal substrate 40 where the two-layer pattern portion 46 is not provided, the metal bus bar 53 is placed on the third conductor pattern 52 and soldered. . Note that the metal bus bar 53 may be soldered and connected to the third conductor pattern 52 before the second insulating layer 43 with the conductor patterns 44 and 45 is attached.
[0017]
In the metal substrate 40 obtained in this way, the surface of the second conductor pattern 45 and the metal bus bar 53 to be connected to the electronic component 61 are formed on the same surface without unevenness. You can print at once. After that, all the electronic components 61 can be mounted on the surface of the metal substrate 40 at a time. In addition, since the first conductor pattern 44 and the second conductor pattern 45 are provided in two layers at the two-layer pattern portion 46, the density of the surface-mounted components can be increased accordingly.
Also, by providing the metal bus bar 53 on the metal base 41, a large current can be easily passed through the metal bus bar 53 without being forced to design the conductor patterns 44, 45, 52 corresponding to the increase in current. Moreover, if the back surface of the electronic component 61 that generates heat is thermally connected to the metal bus bar 53, the electronic component 61 can be effectively dissipated by the metal bus bar 53. Can be miniaturized.
[0018]
As described above, in this embodiment, at least the second insulation is provided in the metal substrate 40 in which the first insulating layer 42 is provided on the surface of the metal base 41 and the conductor patterns 44 and 45 are provided on the surface of the first insulating layer 42. A two-layer pattern portion 46 provided with conductor patterns 44 and 45 on both sides of the layer is partially provided on the surface of the first insulating layer 42, and a metal bus bar 53 is provided in the recess 51 where the two-layer pattern portion 46 is not provided. The surface of the metal bus bar 53 and the surface of the conductive pattern (second conductor pattern 45) are formed flush with each other.
[0019]
When the metal substrate 40 is configured in this way, the first conductor pattern 44 and the second conductor pattern 45 are provided in two layers at the portion to be the two-layer pattern portion 46, and accordingly, the portion is formed on the surface of the metal substrate 40 accordingly. High density of the electronic component 61 to be mounted can be achieved. In addition, since the surface of the second conductor pattern 45 and the metal bus bar 53 to be connected to the electronic component 61 are formed on the same surface without unevenness, printing of the solder paste with a solder mask or the metal substrate 40 is performed. The electronic component 61 can be mounted at a time. Further, by arranging the metal bus bar 53 separately from the conductor patterns 44, 45, 52, a large current can be easily passed through the metal bus bar 53 without being forced to design a pattern corresponding to the increase in current. Therefore, it is possible to provide the metal substrate 40 that can perform the printing of the solder paste and the mounting of the electronic component 61 at the same time without deteriorating the heat dissipation characteristics and can increase the density of the electronic component 61 to be mounted.
[0020]
In addition, in such a configuration, it is preferable that a thermal connection portion that is thermally connected to the back surface of the electronic component 61 mounted on the metal substrate 40 is formed on the surface of the metal bus bar 53. In this way, the metal bus bar 53 can be used as a heat radiating member of the electronic component 61, not simply for the purpose of flowing a large current.
[0021]
In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible. For example, in the embodiment, the two-layer pattern portion 46 in which the first conductor pattern 44 and the second conductor pattern 45 are provided on both surfaces of the second insulating layer 43 is shown, but a multilayer pattern portion having three or more layers of conductive patterns may be used. Good.
[0022]
【The invention's effect】
The present invention provides a multi-layer pattern in which a first insulating layer is provided on a surface of a metal base and a conductive pattern is provided on the surface of the first insulating layer, and a conductive pattern is provided on both surfaces of at least the second insulating layer. A metal bus bar is provided in a recess not provided with the multilayer pattern portion, and the surface of the metal bus bar and the surface of the conductive pattern are formed flush with each other. In addition, it is possible to provide a metal substrate that can perform solder paste printing and electronic component mounting at the same time without degrading heat dissipation characteristics, and that can increase the density of the mounted components.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a metal substrate in a component mounting state according to an embodiment of the present invention.
FIG. 2 is a partial perspective view of the metal substrate in the same component mounting state.
FIG. 3 is a cross-sectional view of a metal substrate showing a conventional example.
FIG. 4 is a cross-sectional view of a metal substrate showing another conventional example.
FIG. 5 is a cross-sectional view of a metal substrate showing still another conventional example.
[Explanation of symbols]
41 metal base
44 1st conductor pattern (conductor pattern)
45 Second conductor pattern (conductor pattern)
46 Two-layer pattern part (multi-layer pattern part)
51 recess
53 metal busbar

Claims (1)

In the metal substrate in which the first insulating layer is provided on the surface of the metal base and the conductor pattern is provided on the surface of the first insulating layer, the multilayer pattern portion in which the conductor pattern is provided on at least both surfaces of the second insulating layer is provided. 1. A metal characterized in that it is provided partially on the surface of an insulating layer, a metal bus bar is provided in a recess not provided with the multilayer pattern portion, and the surface of the metal bus bar and the surface of the conductive pattern are formed flush with each other. substrate.

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