JP2008021817A - Heat conducting base board, manufacturing method thereof, power supply unit, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat conducting base board hardly influenced by noises, to provide a manufacturing method thereof, to provide a power supply unit, and to provide electronic equipment. <P>SOLUTION: The heat conducting base board consists of metal plates 17 each having one or more holes, a sheet-like heat transfer resin layer 11 fixed on the metal plate 17, lead frames 10 embedded in the heat transfer resin layer 11, and a printed wiring board 20 provided in the hole of the metal plate 17. A part of the lead frames 10 is bent toward the holes, the bent portions 13 pierce through the heat transfer resin layer 11 and is electrically connected to the printed wiring board. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat conductive substrate used in a high power circuit such as a power circuit of an electronic device, a manufacturing method thereof, a power supply unit, and an electronic device.

  In recent years, along with the demand for higher performance and smaller size of electronic devices, higher density and higher functionality of electronic components such as semiconductors have been demanded. In order to meet this demand, circuit boards on which various electronic components are mounted are also required to be small and high in density. As a result, a power semiconductor or the like having a relatively large heat generation amount (for example, controlling a large current of several tens of A or more) such as a switching element and a signal current having a relatively small amount of heat generation (for example, several tens mA) are controlled. ) In some cases, it is required to mount general electronic components such as control semiconductors separately on a circuit board suitable for each application and connect them to each other. In order to meet such needs, Patent Document 1 discloses that a large current circuit unit such as large current switching and a control signal circuit unit are separately created and connected to each other by wiring. . Next, a case where a large current portion and a control signal circuit portion are separated from each other will be described with reference to the drawings.

  9A and 9B are top views showing a conventional heat conductive substrate. FIG. 9A is a top view of a large current circuit portion on which a power semiconductor is mounted. In FIG. 9A, the large current circuit 3 includes an insulating material 2 and lead frames 1a to 1c formed thereon. The reason for using the lead frames 1a to 1c is to cope with a large current and high heat dissipation.

FIG. 9B is a top view after the power element and the control element are mounted. In FIG. 9B, a control element 4 made of a semiconductor element, a chip part, or the like constituting a control circuit for controlling the power semiconductor 7 is mounted on a printed wiring board 5. This is because it is cheaper to use the printed wiring board 5 than to use the lead frames 1a to 1c, and it can cope with high-density mounting. The control circuit thus created and the large current circuit 3 are connected by the lead wire 6. In FIG. 9B, the external electrodes of the power semiconductor 7 and the soldered portions connecting the external electrodes and the lead frames 1a to 1c are not shown.
JP 2004-342325 A

  As described above, in the conventional structure, the lead wire 6 connecting the power semiconductor 7 and the control element 4 becomes long. Therefore, noise caused by the power element 3 on the lead wire 6 (high frequency generated by switching the power semiconductor at high frequency). Noise) is easier to ride. As a result, the control element 4 that controls the power element 3 is likely to malfunction, and the output from the power element 3 becomes unstable.

  It is an object of the present invention to provide a heat conductive substrate that is not easily affected by such noise, a manufacturing method thereof, a power supply unit, and an electronic device.

  In order to solve the conventional problems, the present invention provides a metal plate having one or more holes, a sheet-like heat transfer resin layer fixed on the metal plate, and embedded in the heat transfer resin layer. A lead frame and a printed circuit board installed in the hole of the metal plate, wherein a part of the lead frame is bent toward the hole, and the bent portion Is a heat conductive substrate that penetrates the heat transfer resin layer and is electrically connected by the printed wiring board.

  With such a configuration, it is possible to provide a heat conductive substrate that is less susceptible to noise, a manufacturing method thereof, a power supply unit, and an electronic device.

  Furthermore, since the heat conductive substrate itself is less susceptible to noise, the power conversion (switching or inverter) efficiency can be increased, and the power consumption of the device can be reduced. In addition, by removing the noise countermeasure parts used in the control circuit, the cost of the power supply unit and the electronic device can be reduced.

  As described above, according to the present invention, by producing a heat conductive substrate that is not easily affected by noise, not only low power consumption of equipment but also cost reduction is realized.

  The series of manufacturing steps shown in the embodiment of the present invention is performed using a molding die. However, the molding die is not shown unless it is necessary for explanation. Further, the drawings are schematic views and do not show the positional relations in terms of dimensions.

(Embodiment 1)
Hereinafter, the heat conductive substrate according to Embodiment 1 of the present invention will be described with reference to the drawings.

  1A and 1B are cross-sectional views of the heat conductive substrate according to the first embodiment. FIG. 1A is a cross-sectional view of the heat conductive substrate before mounting the power element.

  In FIG. 1A, 10 is a lead frame, 11 is a heat transfer resin layer, 12 is a floating island, and 13 is a bent portion. The bent portion 13 is obtained by bending a part of the lead frame 10 or the floating island 12. The lead frame 10 and the floating island 12 are embedded in the heat transfer resin layer 11. Reference numeral 14 denotes a power element, and 15 denotes a terminal. The external electrode of the power element 14 corresponds to the terminal 15. Reference numeral 16 denotes a control element, which corresponds to a semiconductor element or a chip component that constitutes a control circuit for controlling the power element 14. Reference numeral 17 is a metal plate, 18 is solder, 19a is an arrow, and 20 is a printed wiring board.

  In FIG. 1A, the lead frame 10 and the floating island 12 are embedded in a sheet-like heat transfer resin layer 11. The heat transfer resin layer 11 is fixed on the metal plate 17 with the lead frame 10 and the floating island 12 embedded therein. In addition, one or more holes are formed in the metal plate 17, and the printed wiring board 20 is embedded in the holes. Then, at least one of the lead frame 10 and the floating island 12 is connected to the printed wiring board 20 via the bent portion 13. The bent portion 13 is formed by bending a part of the lead frame 10 or the floating island 12 as will be described later with reference to FIG. The lead frame 10 and the floating island 12 are connected to the printed wiring board 20 through the bent portion 13. A solder 18 is formed on the lead frame 10 and the floating island 12, and the power element 14 is mounted thereon as indicated by an arrow 19a. It is desirable that electrical connection between the lead frame 10 and the floating island 12 and the printed wiring board 20 is performed at a plurality of locations (particularly at two or more different locations). By connecting at two or more places that are insulated from each other, a control signal can be easily transmitted to the power element 14. It is not necessary to form the bent portion 13 in all of the lead frame 10 and the floating island 12.

  As described above, the bent portion 13 formed in a part of the lead frame 10 and the floating island 12 embedded in the heat transfer resin layer 11 penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20. Will be connected.

  FIG. 1B is a cross-sectional view of the heat conductive substrate after the power element is mounted. In FIG. 1 (B), 19b is an arrow. 21 is a mold resin, which protects the printed wiring board 20 on which the control element 16 is mounted. It is desirable that the mold resin 21 has a thickness that does not protrude from the metal plate 17. This is because when the mold resin 21 becomes thick and protrudes from the metal plate 17, when the metal plate 17 is mounted on another heat radiating plate (for example, a heat radiating fin, which is not shown), This is because there is a possibility of hindering adhesion with other heat sinks. As shown in FIG. 1B, the terminal 15 of the power element 14 is connected to the lead frame 10 and the floating island 12 via the solder 18. Further, a large current of several tens of A can be supplied to the power element 14 via the lead frame 10. The heat generated in the power element 14 is radiated from the lead frame 10 to the metal plate 17 through the heat transfer resin layer 11 as indicated by an arrow 19b. A control signal for controlling the power element 14 is transmitted from the printed wiring board 20 on which the control element 16 is mounted to the lead frame 10 and the floating island 12 via the bent portion 13 and then to the power element 14 via the terminal 15. To control.

  Thus, the structure proposed in the first embodiment of the present invention allows the power element 14 and the control circuit for the power element 14 to be connected in the shortest distance, and noise caused by the power element 14 is generated in the control circuit. It becomes difficult to influence. Next, a more detailed description will be given with reference to FIG.

  2A and 2B are perspective views of the heat conductive substrate proposed in the first embodiment as viewed from the bottom side (turned over). In FIG. 2, reference numeral 22 denotes a hole, and a control circuit protected by the mold resin 21 is embedded in the hole 22. By setting the height of the mold resin 21 lower than the surface of the metal plate 17 in this way, the mold resin 21 does not protrude when the metal plate 17 is attached (or fixed) to another member. It does not get in the way.

  FIG. 2B corresponds to a perspective view after removing the mold resin 21 of FIG. 2B that the printed wiring board 20 on which the control element 16 is mounted is embedded in one or more holes 22 formed in the metal plate 17. 2A and 2B, a plurality of lead frames 10 embedded in the heat transfer resin layer 11 protrude in a bar shape on the back surface of the metal plate 17, and the lead frame 10 is, for example, a power source. It becomes the input (plus, minus) and output of the circuit. Next, the heat conductive substrate in Embodiment 1 of this invention is demonstrated using FIG.

  FIGS. 3A to 3D are a top view of the heat conductive substrate according to Embodiment 1 of the present invention, and a top view and a perspective view of a power element mounted on the heat conductive substrate. First, description will be made with reference to FIGS. FIG. 3A is a top view after the power element is mounted on the heat conductive substrate according to Embodiment 1 of the present invention. In FIG. 3A, the power element 14 is connected to the lead frames 10 a to 10 c via the terminal 15.

  Here, when the heat conductive substrate in Embodiment 1 is applied to a power supply circuit, the lead frame 10b in FIG. 3A corresponds to a plus input of the power supply circuit. Similarly, the lead frame 10c corresponds to the negative input of the power supply circuit, and the lead frame 10a corresponds to the output of the power supply circuit. Further, the portions protruding from the heat transfer resin layer 11 of the lead frames 10a to 10c are processed into a comb-teeth shape, so that the end portions of the lead frames 10a to 10c can be easily connected to other substrates. . In FIG. 3A, the portion where the heat transfer resin layer 11 protrudes from the lead frames 10a to 10c is to increase the creepage distance. In FIG. 3A, the solder 15 and the solder resist that connect the terminal 15 of the power element 14 to the lead frames 10a to 10c and the floating island 12 (not shown because it is a shadow of the terminal 15) are shown. Absent.

  FIG. 3B is a top view showing a state where the power element is removed from FIG. In FIG. 3B, it can be seen that floating islands 12 are formed in the gaps between the lead frames 10a to 10c. Here, the floating island 12 indicates a pattern portion independent (or insulated) from the lead frames 10a to 10c. The lead frames 10a to 10c indicate pattern portions that can be connected from the heat transfer resin layer 11 to an external circuit via the comb-shaped processed portion.

  FIG. 3C is a top view of the power element. The power element 14 is formed of a resin-molded portion and terminals 15 formed at both ends thereof. Here, the power element 14 is a switching element (for example, a power transistor) such as a converter or an inverter. A part of the terminal 15 may be a dummy element for enhancing heat dissipation.

  FIG. 3D is a perspective view of the power element. In FIG. 3D, the power element 14 is a bare chip (a semiconductor element that is not resin-molded). In FIG. 3D, reference numeral 23 denotes a wire, which is a gold or aluminum wire, which is attached with a wire bonder. As shown in FIG. 3D, by using the power element 14 as a bare chip and using a wire 23 made of aluminum or the like, high-density mounting can be performed while supporting a large current of several tens of A. In addition, it cannot be overemphasized that it can respond to the further large electric current by increasing the thickness of the wire 23, or the number. One end of the wire 23 is connected to the power element 14, and the other end is connected to the lead frame 10 and the floating island 12. Then, the power element 14 and the control circuit are connected with the shortest distance through the bent portion 13 formed in the lead frame 10 and the floating island 12. Next, the back surface of the heat conductive substrate will be described with reference to FIG.

  4 (A) and 4 (B) are back views of the heat conductive substrate according to Embodiment 1 of the present invention. In FIG. 4A, the metal plate 17 has one or more holes 22 formed therein. The printed wiring board 20 on which the control element 16 is mounted is fixed in the hole 22 (note that the mold resin 21 protecting the control element 16 and the printed wiring board 20 is not shown). Further, the comb-shaped lead frames 10a to 10c protruding from the metal plate 17 are portions to be lead wirings for connecting the heat conductive substrate to another substrate. FIG. 4B is a rear view showing a state in which the control element 16 is removed from FIG. 4A (in addition, a predetermined wiring pattern made of copper foil formed on the surface layer of the printed wiring board 20, a solder resist, etc. Is not shown). By using a commercially available glass epoxy substrate as the printed wiring board 20, cost reduction and high reliability can be obtained. Further, by using a double-sided (or multilayer) board as the printed wiring board 20, the control circuit can be reduced in size and density. The thickness of the printed wiring board 20 is desirably 2.0 mm or less. When the thickness exceeds 2.0 mm, it is necessary to increase the thickness of the metal plate 17, which may increase the cost. Therefore, the thickness of the printed wiring board 20 is desirably 1.6 mm or less (further 1.2 mm or less, more desirably 0.6 mm or less, and further 0.3 mm or less). The thickness of the printed wiring board 20 is desirably 0.05 mm or more. This is because if the thickness of the printed wiring board is less than 0.05 mm, it becomes special and expensive.

  As described above, the metal plate 17 having one or more holes, the sheet-like heat transfer resin layer 11 fixed on the metal plate 17, the lead frame 10 embedded in the heat transfer resin layer 11, A heat conductive substrate comprising a printed wiring board 20 installed in a hole of a metal plate 17, wherein a part of the lead frame 10 is bent toward the hole 22, and the bent portion 13 is By using a heat conductive substrate that penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20, it is possible to suppress the influence of noise on the heat dissipation substrate, and to reduce the size and cost of the device. Realize.

  Next, as a second embodiment, a method for manufacturing the heat dissipation substrate described in the first embodiment will be described with reference to the drawings.

(Embodiment 2)
Next, as a second embodiment, a method for manufacturing the heat dissipation substrate described in the first embodiment will be described with reference to the drawings. FIGS. 5-8 demonstrates an example of the manufacturing method of a thermal radiation board | substrate.

  5A to 5D are a top view and a cross-sectional view illustrating a method for manufacturing a heat dissipation substrate. 5A to 5D, reference numeral 24 denotes a film. First, as shown in FIG. 5A, a commercially available copper plate or the like is punched into a predetermined wiring pattern to obtain lead frames 10a to 10c. At this time, a part thereof can be processed simultaneously to form the bent portion 13. FIG. 5B is a cross-sectional view taken along arrow 19 in FIG. Next, as shown in FIG. 5C, the lead frames 10 a to 10 c are temporarily fixed to the surface of the film 24. Here, as the film 24, a resin film having an adhesive layer on one side can be used. FIG. 5D is a cross-sectional view taken along arrow 19 in FIG. Next, formation of the floating island 12 will be described with reference to FIG.

  6A to 6D are a perspective view, a side view, a cross-sectional view, and a top view showing how floating islands are formed. FIG. 6A is a perspective view showing a floating island. As shown in FIG. 6A, a bent portion 13b is formed in a part of the floating island 12. FIG. 6B is a side view of the floating island, and it can be seen that a part of the floating island 12 is processed to form a bent portion 13b. Next, as shown in FIG. 6C, the floating island 12 is fixed (or temporarily fixed) on the film 24 exposed between the lead frames 10a. Thus, the state shown in FIG.

  7A and 7B are cross-sectional views showing a state in which the lead frame and the floating island are integrated through the heat transfer resin. First, as shown in FIG. 7A, a heat transfer resin material composed of a resin and a filler is set in a sheet form on the lead frame 10 a and the floating island 12 temporarily fixed on the film 24. Here, the heat transfer resin material is formed into a sheet shape, and the central portion thereof is slightly inflated (thickened), so that air hardly remains at the interface between the heat transfer resin layer 11 and the lead frame 10a or the floating island 12. 7A, as shown by an arrow 19, the sheet-like heat transfer resin layer 11 is pierced into a bent portion 13a that is a part of the lead frame 10a or a bent portion 13b that is a part of the floating island 12. Thus, the heat transfer resin layer 11 may be broken through. Note that holes may be formed in advance in the sheet-like heat transfer resin layer 11 using a drill, a laser, or the like. Moreover, when integrating these, it is desirable to heat a metal mold | die (not shown). The fluidity of the heat transfer resin material can be improved by heating the mold.

  7A and 7B, the printed wiring board 20 may be a commercially available product (a state in which a solder resist or the like is formed and a wiring continuity check is completed). Alternatively, a predetermined control element 16 mounted with solder 18 or the like may be used. Further, after these control elements 16 are mounted, those further protected with a mold resin 21 may be used. By protecting with the mold resin 21 in this way, when the power element 14 is soldered, even if the solder 18 for fixing the control element 16 is remelted, it does not peel off.

  Next, as shown in FIG. 7B, a metal plate 17 having one or more holes 22 and a printed wiring board 20 are set, and are pressed and integrated as indicated by an arrow 19. In FIGS. 7A and 7B, the mold is not shown. FIG. 8 is a diagram showing a state after the integration.

  8A to 8D are a rear view and a cross-sectional view showing a state after integration. FIG. 8A is a rear view after integration. In FIG. 8A, a film 24 is a kind of temporary fixing material, and the lead frames 10a to 10c and the floating island 12 are embedded in the heat transfer resin layer 11 on the metal 24 and have a hole 22 in part. It can be seen that it is integrated with the plate 17. A printed wiring board 20 is embedded in the hole 22 formed in the metal plate 17.

  A cross-sectional view taken along arrow 19 in FIG. 8A corresponds to FIG. By using the film 24 in this manner, the lead frame 10 a and the floating island 12 are fixed to the metal plate 17 in a state where the lead frame 10 a and the floating island 12 are embedded in the heat transfer resin layer 11. Further, in the hole 22 formed in the metal plate 17, the bent portions 13 a and 13 b integrated with the lead frame 10 a and the floating island 12 are connected to the printed wiring board 20. FIG. 8C is a rear view after the film is peeled off. FIG. 8D is a cross-sectional view taken along arrow 19 in FIG. In this way, the heat dissipation substrate is manufactured. In FIG. 8, the wiring pattern, solder resist, etc. on the surface of the printed wiring board 20 are not shown. Then, solder resist or the like is formed on the surfaces of the lead frames 10a to 10c (the solder resist can be formed to control the wetting and spreading of the solder 18 on the surfaces of the lead frames 10a to 10c), and a predetermined characteristic inspection is performed. After performing, it completes as a heat dissipation board.

  This will be described in more detail. The heat transfer resin layer 11 and the surfaces of the lead frames 10a to 10c are further flush with each other (preferably with a step difference of 50 μm or less, more preferably 20 μm or less, and even less than 10 μm), so that it is easy to form a solder resist. It becomes. Further, since the thickness difference between the heat transfer resin layer 11 and the lead frames 10a to 10c is small, the thickness variation of the solder resist can be suppressed, and the mountability of the electronic component can be improved.

  The heat transfer resin layer 11 is preferably composed of 70 to 95% by weight of an inorganic filler and 5 to 30% by weight of a thermosetting resin. Here, the inorganic filler has a substantially spherical shape, and its diameter is suitably from 0.1 μm to 100 μm (if it is less than 0.1 μm, it becomes difficult to disperse in the resin, and if it exceeds 100 μm, the heat transfer resin layer 11 Increases the thickness of the material, affecting the thermal diffusivity). Therefore, the filling amount of the inorganic filler in the heat transfer resin layer 11 is filled at a high concentration of 70 to 95% by weight in order to increase the thermal conductivity. In particular, in the present embodiment, the inorganic filler is a mixture of two types of alumina having an average particle diameter of 3 μm and an average particle diameter of 12 μm. By using alumina having two kinds of large and small particle diameters, it is possible to fill the gaps between the large particle diameters of alumina with small particle diameters, so that alumina can be filled at a high concentration to nearly 90% by weight. As a result, the heat conductivity of the heat transfer resin layer 11 is about 5 W / (m · K). The inorganic filler may include at least one selected from the group consisting of magnesium oxide, boron nitride, silicon oxide, silicon carbide, silicon nitride, and aluminum nitride instead of alumina.

  When an inorganic filler is used, the heat dissipation can be improved, but in particular when magnesium oxide is used, the linear thermal expansion coefficient can be increased. Further, when silicon oxide is used, the dielectric constant can be reduced, and when boron nitride is used, the linear thermal expansion coefficient can be reduced. Thus, the heat transfer resin layer 11 having a thermal conductivity of 1 W / (m · K) or more and 20 W / (m · K) or less can be formed. In addition, when heat conductivity is less than 1 W / (m * K), it influences the heat dissipation of a heat conductive board | substrate. Moreover, when it is going to make thermal conductivity higher than 20 W / (m * K), it is necessary to increase the amount of fillers and may affect the workability at the time of a press.

  The thermosetting resin contains at least one kind of resin among epoxy resin, phenol resin and cyanate resin. These resins are excellent in heat resistance and electrical insulation. If the thickness of the heat transfer resin layer 11 is reduced, the heat generated in the electronic component mounted on the lead frame 10 can be easily transferred to the metal plate 17, but conversely, withstand voltage is a problem. Therefore, the optimum thickness may be set to 50 μm or more and 1000 μm or less in consideration of the withstand voltage and the thermal resistance.

  Next, the material of the lead frame 10 will be described. As a material of the lead frame 10, a material mainly composed of copper (for example, a copper plate) is desirable. This is because copper has both excellent thermal conductivity and electrical conductivity. In order to improve the workability and thermal conductivity of the lead frame 10, the copper material used as the lead frame 10 is selected from a group of at least Sn, Zr, Ni, Si, Zn, P, Fe, etc. other than copper. It is also possible to use an alloy made of at least one kind of material. For example, it is possible to use a copper material (hereinafter referred to as Cu + Sn) in which Cu is mainly used and Sn is added thereto. In the case of a Cu + Sn copper material (or copper alloy), for example, by adding Sn to 0.1 wt% or more and less than 0.15 wt%, the softening temperature can be increased to 400 ° C. For comparison, when the lead frame 10 is made using copper without Sn (Cu> 99.96 wt%), the conductivity is low, but the formed heat conduction substrate is particularly distorted in the formation portion or the like. was there. As a result, the softening point of the material was as low as about 200 ° C., and it was expected that the material could be deformed during subsequent component mounting (soldering). On the other hand, when a copper-based material with Cu + Sn> 99.96% by weight was used, it was not particularly affected by the heat generation of various mounted parts. There was no effect on solderability and die bondability. Therefore, when the softening point of this material was measured, it was found to be 400 ° C. Thus, it is desirable to add some elements mainly composed of copper. As an element added to copper, in the case of Zr, the range of 0.015 wt% or more and 0.15 wt% or less is desirable. When the addition amount is less than 0.015% by weight, the effect of increasing the softening temperature may be small. On the other hand, if the amount added is more than 0.15% by weight, the electrical characteristics may be affected. Also, the softening temperature can be increased by adding Ni, Si, Zn, P or the like. In this case, Ni is 0.1 wt% or more and less than 5 wt%, Si is 0.01 wt% or more and 2 wt% or less, Zn is 0.1 wt% or more and less than 5 wt%, and P is 0.005 wt% or more. Less than 0.1% by weight is desirable. And these elements can make the softening point of a copper raw material high by adding single or multiple in this range. In addition, when there are few addition amounts than the ratio described here, the softening point raise effect may be low. Moreover, when there are more than the ratio described here, there exists a possibility of affecting the electrical conductivity. Similarly, in the case of Fe, 0.1 wt% or more and 5 wt% or less is desirable, and in the case of Cr, 0.05 wt% or more and 1 wt% or less are desirable. These elements are the same as those described above.

  The tensile strength of the copper material used for the lead frame 10 is desirably 600 N / square mm or less. In the case of a material having a tensile strength exceeding 600 N / square mm, the workability of the lead frame 10 may be affected. On the other hand, by setting the tensile strength to 600 N / square mm or less (and, if the lead frame 10 requires fine and complicated processing, desirably 400 N / square mm or less), the spring back (pressure even if bent to the required angle) If it is removed, it will be repelled by the reaction force), and the formation accuracy can be improved. As described above, as the lead frame material, the conductivity is lowered by mainly using Cu, and the workability is improved by further softening, and the heat dissipation effect by the lead frame 10 is also enhanced. The tensile strength of the copper alloy used for the lead frame 10 is desirably 10 N / square mm or more. This is because the copper alloy used for the lead frame 10 needs to have a strength higher than the tensile strength (about 30 to 70 N / square mm) of general lead-free solder. When the tensile strength of the copper alloy used for the lead frame 10 is less than 10 N / square mm, when electronic components are soldered and mounted on the lead frame 10, there is a possibility of cohesive failure at the lead frame 10 portion instead of the solder portion. There is.

  It is also useful to previously form a solder layer or a tin layer on the surface of the lead frame 10 exposed from the heat transfer resin layer 11 (the mounting surface of the electronic component or the like) so as to improve solderability. is there. Note that it is desirable not to form a solder layer on the surface (or embedded surface) of the lead frame 10 in contact with the heat transfer resin layer 11. When a solder layer or a tin layer is formed on the surface in contact with the heat transfer resin layer 11 in this way, this layer becomes soft during soldering, which affects the adhesion (or bond strength) between the lead frame 10 and the heat transfer resin layer 11. May give. The metal plate 17 is made of aluminum, copper, or an alloy containing them as a main component with good thermal conductivity. In particular, in the present embodiment, the thickness of the metal plate 17 is set to 1 mm, but the thickness can be designed according to product specifications (note that if the thickness of the metal plate 17 is 0.1 mm or less, in terms of heat dissipation and strength) In addition, if the thickness of the metal plate 17 exceeds 50 mm, it is disadvantageous in terms of weight). The metal plate 17 is not only a plate-like one, but in order to increase heat dissipation, a fin portion (or uneven portion) is provided on the surface opposite to the surface on which the heat transfer resin layer 11 is laminated in order to increase the surface area. ) May be formed. The total expansion coefficient is 8 to 20 ppm / ° C., and warpage and distortion of the heat conductive substrate of the present invention and the entire power supply unit using the same can be reduced. In addition, when these components are surface-mounted, matching the thermal expansion coefficients with each other is also important in terms of reliability.

  Thus, the metal plate 17 having one or more holes 22, the sheet-like heat transfer resin layer 11 fixed on the metal plate 17, the lead frame 10 embedded in the heat transfer resin layer 11, A heat conductive substrate comprising a printed wiring board 20 installed in the hole 22 of the metal plate 17, wherein a part of the lead frame 10 is bent toward the hole 22, and the bent portion By providing a heat conductive substrate 13 that penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20, it is difficult to be affected by noise generated by switching of the power element 14. In addition to preventing malfunction of the power supply circuit, the projected floor area of the substrate can be reduced, contributing to the downsizing and cost reduction of the equipment.

  Further, the metal plate 17 having at least one hole 22, the sheet-like heat transfer resin layer 11 fixed on the metal plate 17, the lead frame 10 embedded in the heat transfer resin layer 11, and the heat transfer It is a heat conductive substrate comprising a floating island 12 embedded in the resin layer 11 and a printed wiring board 20 installed in the hole 22 of the metal plate 17, and a part of the lead frame 10 is formed in the hole 22. The power element 14 is switched by providing a heat conductive substrate that is bent in the direction and the bent portion 13 penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20. As a result, the power circuit can be prevented from malfunctioning, the projected floor area of the substrate can be reduced, and the device can be reduced in size and cost.

  Further, at least the metal plate 17 having one or more holes 22, the sheet-like heat transfer resin layer 11 fixed on the metal plate 17, the lead frame 10 embedded in the heat transfer resin layer 11, and the above A heat conductive substrate comprising a floating island 12 embedded in the heat transfer resin layer 11, wherein a part of the floating island 12 is bent toward the hole 22, and the bent portion 13 is the heat transfer resin layer. By providing a heat conductive substrate that penetrates 11 and is electrically connected to the printed wiring board 20, it is less susceptible to noise generated by switching of the power element 14, and prevents malfunction of the power supply circuit. In addition, the projected floor area of the substrate can be reduced, contributing to downsizing and cost reduction of equipment.

  Similarly, at least a metal plate 17 having one or more holes 22, a heat transfer resin layer 11 fixed on the metal plate 17, a lead frame 10 embedded in the heat transfer resin layer 11, and the heat transfer A thermal conductive substrate comprising a floating island 12 embedded in the resin layer 11 and a printed wiring board 20 fixed in the hole 22 of the metal plate 17, wherein the floating island 12 and a part of the lead frame 10 are By providing a heat conductive substrate that is bent toward the hole 22 and the bent portion 13 penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20, the power This makes it less susceptible to noise generated by switching of the element 14, prevents malfunction of the power supply circuit, reduces the projected floor area of the substrate, and contributes to downsizing and cost reduction of the device.

  Similarly, at least a part of the lead frame 10 or the floating island 12 is bent to form a bent portion 13, a step of the bent portion 13 penetrating the heat transfer resin material, the lead frame 10 or the floating island 12, A step of laminating and integrating the metal plate 17 having one or more holes 22 with the heat transfer resin material, and electrically connecting the bent portion 13 of the lead frame 10 or the floating island 12 and the printed wiring board 20. And a manufacturing method of the heat conductive substrate having the steps, the influence of noise generated by the switching of the power element 14 can be reduced, the malfunction of the power supply circuit can be prevented, the device can be downsized and the cost can be reduced. Can contribute to

  Furthermore, at least a metal plate 17 having one or more holes 22, a sheet-like heat transfer resin layer 11 fixed on the metal plate 17, a lead frame 10 embedded in the heat transfer resin layer 11, and the metal A heat conductive substrate comprising a printed wiring board 20 fixed in a hole 22 of the board 17, wherein a part of the lead frame 10 is bent toward the hole 22, and the bent portion 13 is By providing a power supply unit using a heat conductive substrate that penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20, the influence of noise generated by switching of the power element 14 can be reduced. This makes it difficult to receive power, prevents malfunction of the power supply circuit, reduces the projected floor area of the substrate, and contributes to downsizing and cost reduction of the equipment.

  Furthermore, at least a metal plate 17 having one or more holes 22, a sheet-like heat transfer resin layer 11 fixed on the metal plate 17, a lead frame 10 embedded in the heat transfer resin layer 11, and the metal A printed circuit board 20 fixed in the hole 22 of the board 17 and a heat conductive substrate made of the floating island 12, wherein the lead frame 10 and a part of the floating island 12 are bent toward the hole 22. By providing a power supply unit using a heat conductive substrate in which the bent portion 13 penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20, the power element 14 can be switched by switching. This makes it less susceptible to noise generated, prevents malfunction of the power supply circuit, reduces the projected floor area of the substrate, and contributes to downsizing and cost reduction of the equipment.

  Further, at least the metal plate 17 having one or more holes 22, the sheet-like heat transfer resin layer 11 fixed on the metal plate 17, the lead frame 10 embedded in the heat transfer resin layer 11, and the metal A heat conductive substrate comprising a printed wiring board 20 fixed in a hole 22 of the board 17, wherein a part of the lead frame 10 is bent toward the hole 22, and the bent portion 22 is By providing an electronic device using a heat conductive substrate that penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board 20, the influence of noise generated by switching of the power element 14 is reduced. It can be made difficult to receive, and the projected floor area of the substrate can be reduced, contributing to the downsizing and cost reduction of equipment.

  The metal plate 17 having at least one or more holes 22, the sheet-like heat transfer resin layer 11 fixed on the metal plate 17, the lead frame 10 embedded in the heat transfer resin layer 11, and the metal plate 17 is a heat conductive substrate composed of a printed wiring board 20 fixed in a hole 22 and a floating island 12, wherein the lead frame 10 and a part of the floating island 12, or the lead frame 10 or the floating island 12. Is bent toward the hole 22, and the bent portion 13 penetrates the heat transfer resin layer 11 and is electrically connected to the printed wiring board. By providing the equipment, it is difficult to be affected by the noise generated by the switching of the power element 14, the projected floor area of the substrate can be reduced, and the equipment can be reduced in size and cost. It can be.

  As described above, by applying the heat conductive substrate, the manufacturing method thereof, the power supply unit, and the electronic device according to the present invention to various PDPs (plasma display panels), electrical equipment, industrial high power circuits, etc. Miniaturization and high performance are possible.

(A), (B) is sectional drawing of the heat conductive board | substrate in Embodiment 1 of this invention. (A), (B) is the perspective view which looked at the heat conductive board | substrate demonstrated in Embodiment 1 from the bottom part side (turned over). (A)-(D) are the top view of the heat conductive substrate in Embodiment 1 of this invention, and the top view and perspective view of the power element mounted in a heat conductive substrate. (A), (B) is a back view of the heat conductive substrate in Embodiment 1 of the present invention. (A)-(D) are the top view and sectional drawing explaining the manufacturing method of a thermal radiation board | substrate. (A)-(D) are a perspective view, a side view, a cross-sectional view, and a top view showing how a floating island is formed. (A), (B) is sectional drawing which shows a mode that a lead frame and a floating island are integrated through heat-transfer resin. (A)-(D) are the back view and sectional drawing which show the mode after integration. (A), (B) is a top view showing a conventional heat conductive substrate

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lead frame 11 Heat transfer resin layer 12 Floating island 13 Bending part 14 Power element 15 Terminal 16 Control element 17 Metal plate 18 Solder 19 Arrow 20 Printed wiring board 21 Mold resin 22 Hole 23 Wire 24 Film

Claims (14)

A metal plate having one or more holes;
A sheet-like heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
A printed wiring board installed in the hole of the metal plate;
A heat conductive substrate comprising:
A portion of the lead frame is bent toward the hole, and the bent portion penetrates the heat transfer resin layer and is electrically connected to the printed wiring board. A plurality of electronic components are mounted on the surface of the printed wiring board,
The heat conductive substrate according to claim 1, wherein a part or more of the electronic component and the printed wiring board is protected with a mold resin. A plurality of electronic components are mounted on the surface of the printed wiring board,
The heat conductive substrate according to claim 1, wherein at least a part of the electronic component and the printed wiring board is covered within a thickness range in which mold resin does not protrude from the metal plate. The heat conductive substrate according to claim 1, wherein the heat transfer resin includes at least one kind of resin selected from the group consisting of an epoxy resin, a phenol resin, and an isocyanate resin. The heat conductive substrate according to claim 1, wherein the inorganic filler includes at least one selected from the group consisting of alumina, magnesium oxide, boron nitride, silicon oxide, silicon carbide, silicon nitride, and aluminum nitride. In the lead frame, Sn is 0.1% by weight to 0.15% by weight, Zr is 0.015% by weight to 0.15% by weight, Ni is 0.1% by weight to 5% by weight, and Si is 0%. 0.01 wt% or more and 2 wt% or less, Zn is 0.1 wt% or more and 5 wt% or less, P is 0.005 wt% or more and 0.1 wt% or less, Fe is 0.1 wt% or more and 5 wt% or less The heat conductive substrate according to claim 1, wherein the heat conductive substrate is a metal material mainly composed of copper, including at least one selected from the group consisting of: at least,
A metal plate having one or more holes;
A sheet-like heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
Floating islands embedded in the heat transfer resin layer,
A printed wiring board installed in the hole of the metal plate;
A heat conductive substrate comprising:
A portion of the lead frame is bent toward the hole, and the bent portion penetrates the heat transfer resin layer and is electrically connected to the printed wiring board. at least,
A metal plate having one or more holes;
A sheet-like heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
Floating islands embedded in the heat transfer resin layer,
A heat conductive substrate comprising:
A portion of the floating island is bent toward the hole, and the bent portion penetrates the heat transfer resin layer and is electrically connected to the printed wiring board. at least,
A metal plate having one or more holes;
A heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
Floating islands embedded in the heat transfer resin layer,
A printed wiring board fixed in the hole of the metal plate;
A heat conductive substrate comprising:
A portion of the floating island and the lead frame is bent toward the hole, and the bent portion penetrates the heat transfer resin layer and is electrically connected to the printed wiring board. at least,
Bending a portion of the lead frame or floating island to form a bent portion;
A step in which the bent portion penetrates the heat transfer resin material;
Laminating and integrating the lead frame or floating island and a metal plate having one or more holes with the heat transfer resin material;
Electrically connecting the bent portion of the lead frame or floating island and the printed wiring board;
The manufacturing method of the heat conductive board | substrate which has this. at least,
A metal plate having one or more holes;
A sheet-like heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
A printed wiring board fixed in the hole of the metal plate;
A heat conductive substrate comprising:
A power supply using a heat conductive substrate in which a part of the lead frame is bent toward the hole, and the bent portion penetrates the heat transfer resin layer and is electrically connected to the printed wiring board. unit. at least,
A metal plate having one or more holes;
A sheet-like heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
A printed wiring board fixed in the hole of the metal plate;
A thermal conductive substrate made of floating islands,
A part of the lead frame and the floating island, or a part of the lead frame or the floating island is bent toward the hole, and the bent portion penetrates the heat transfer resin layer, and the printed wiring board. A power supply unit using a heat conductive board that is electrically connected to at least,
A metal plate having one or more holes;
A sheet-like heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
A printed wiring board fixed in the hole of the metal plate;
A heat conductive substrate comprising:
A part of the lead frame is bent toward the hole, and the bent portion penetrates the heat transfer resin layer and is electrically connected to the printed wiring board. machine. at least,
A metal plate having one or more holes;
A sheet-like heat transfer resin layer fixed on the metal plate;
A lead frame embedded in the heat transfer resin layer;
A printed wiring board fixed in the hole of the metal plate;
A thermal conductive substrate made of floating islands,
A part of the lead frame and the floating island, or a part of the lead frame or the floating island is bent toward the hole, and the bent part penetrates the heat transfer resin layer, and the printed wiring board. Electronic equipment using a heat conductive substrate that is electrically connected to

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