JP6512262B2 - Heat dissipation board - Google Patents

Description

  The present invention relates to a heat dissipation board on which an electronic component is mounted, and more specifically, a hole is provided leaving a thin portion from the back surface side of the electronic component mounting surface of the heat dissipation board toward the electronic component mounting surface. A conductor is inserted into the hole, and a filler is filled between the hole and the conductor, for example, to generate heat from the heat generating electronic component mounted on the electronic component mounting surface side. The present invention relates to a heat dissipation board capable of efficiently conducting heat to the back surface side of the electronic component mounting surface to dissipate heat.

  2. Description of the Related Art Conventionally, electronic circuits using power semiconductors and the like that handle large electric power, such as inverter circuits and power supply circuits, have been made into dedicated substrates along with the miniaturization of equipment.

  And, in order to achieve conversion to a dedicated substrate of a circuit using such a power semiconductor, it is an important issue how to efficiently generate heat due to the loss of a high density mounted power semiconductor or the like.

  Then, in order to solve the above problems, for example, a technology as disclosed in Japanese Patent Application Laid-Open No. 2012-92747 (Patent Document 1) is disclosed.

  The technology described in Patent Document 1 is that, in the inverter-integrated electric compressor, a control circuit substrate on which a power semiconductor or the like is mounted is used as a thermally conductive substrate, and one side of the control circuit substrate is used as a control device housing. The heat dissipating flat surface portion is provided so as to be capable of transferring heat, and the other surface of the control circuit board is provided with heat generating power semiconductors and electrical components so as to be able to transfer heat.

  The control circuit board is provided with a substrate body made of an insulator, and a heat conduction penetrating member made of a good heat conductor which is filled and penetrated in the thickness direction of the substrate body, and the heat conduction penetrating The member has a structure in which one end face thereof is disposed to be able to transmit heat to the heat radiation flat portion, and the other end face is arranged to be able to conduct heat transfer to the power semiconductor and the electric component.

JP, 2012-92747, A

  However, in the configuration of the invention described in Patent Document 1, for example, when the number of through holes for the heat conducting through member increases, the rigidity of the substrate itself decreases, and measures to suppress the generation of warpage or the like over the entire surface of the substrate are taken. Was needed separately.

  Further, in the configuration of the invention described in Patent Document 1, the above-mentioned goodness may be caused depending on the change of the use environment due to the difference of the thermal expansion coefficient between the heat conduction penetrating member made of good heat conductor and the heat conductive substrate body. There has been a problem that there is a high possibility of damaging the thermally conductive penetrating member or thermally conductive substrate body made of the thermally conductive material.

  Further, for example, in a control device of an electric motor used for an electric power steering device of a vehicle or the like, there is a high demand for downsizing of the device since the above device needs to be mounted in the vehicle. However, conventionally, in the control device of the above-mentioned electric power steering apparatus, control calculation based on information such as a dedicated substrate (power substrate) on which a power semiconductor handling high power for driving a motor and the like is mounted And the control board which handles small electric power, etc. were comprised separately inside the said control apparatus.

  That is, conventionally, a conductor pattern (copper foil) is pasted on the surface of a metal supporting plate made of aluminum or the like via a thin insulator layer, and a wiring pattern is formed by etching the conductor foil. On the other hand, the control substrate is a laminated substrate of four or more layers on which a dedicated microcomputer is mounted. Then, in the control device, as shown in a side sectional view of an example of the conventional control device 1400 in FIG. 14, for example, two substrates of the power substrate 1410 and the control substrate 1430 are stacked in upper and lower two stages. A structure in which this is electrically connected by a multipolar connector 1450 or the like mounted between the two substrates is employed.

  Therefore, in order to miniaturize (thin) the control device as described above, it was necessary to combine the above-described two-stage two-sheet substrate into one substrate, but there are many problems to be solved. The For example, in the configuration as described above, since the wiring pattern is formed by etching, the conductor foil is used as thin as about 70 μm, so when constructing a power circuit where a large current flows, the wiring resistance Was a problem. Moreover, in the said board | substrate, the thermal radiation characteristic receives a restriction | limiting by said insulator layer with a low heat transfer coefficient, and the subject that sufficient thermal radiation performance was not obtained occurred.

  Therefore, the present invention aims to solve the above problems and problems, and efficiently dissipates heat of the substrate on which the above power semiconductor and the like are mounted and, as described above, a power semiconductor and the like that handle large electric power. It is an object of the present invention to solve the problem of heat dissipation and the like in the case where a dedicated substrate (power substrate) to be mounted is combined with a control substrate handling small electric power to form an integrated substrate.

In order to solve the above problems, the present invention is a substrate on which a circuit for mounting an electronic component is formed on the component mounting surface side, and a radiator on all or part of the back surface side of the substrate on the component mounting surface side. A hole is provided from the back surface side of the substrate toward the component mounting surface, and the hole does not penetrate the substrate on the component mounting surface side of the hole. A thin film portion is formed on the lower side of a conductive film constituting a circuit formed on the component mounting surface side of the substrate, and the heat generating electronic component disposed on the component mounting surface side of the substrate is formed via the thin thickness portion. provided so as to face Te, wherein a cylindrical heat generating electronic components has a circular shape inscribed in contact surface shape when mounted on the substrate, wherein a circular-shaped outer substrate portion in contact in the The heat dissipating member is supported, and the heat dissipating member is provided inside the hole. From provided erected conductor toward the upper surface of the hole, the conductor, the heat conductive plate has a shape vertically spirally around the cylinder to the bottom surface of the radiator, the A filler is disposed between the inner surface inside the hole and the conductor erected inside the hole, particles of aluminum nitride are mixed in the filler, and the heat sink is The heat sink and the conductor are formed of the same material, and are formed on the surface of the conductor and the substrate of the heat sink. Provided is a heat dissipation substrate characterized in that the facing portion is anodized aluminum.

Also, solving the above problems, the Te radiating substrate smell, the inner surface of the front Kiana portion by covering with the heat conductor has been applied or coated by the heat conductor, the inner surface of the hole Ri by that it is decorated with copper plating, Or, the conductor by a thermally conductive material made of metal, is more effectively achieved.

  Further, the solution of the above-mentioned problems can be achieved more effectively by the thickness of the thin portion being zero or by the substrate being a multilayer substrate.

  Further, to solve the above problems, the heat dissipation substrate integrates the power substrate and the control substrate, or the control device having the heat dissipation substrate, or the electric power steering device having the control device. It is achieved more effectively.

  In the present invention, a power substrate and a control substrate, which have been provided as separate substrate configurations, are compounded on one substrate (two substrates are compounded on one substrate), and the power mounted on the above substrate A hole is provided in the substrate from the back side of the electronic component mounting surface at a position corresponding to the position directly below the heat generating electronic component such as a semiconductor, and a conductor made of a heat conductive material erected from a heat sink is embedded therein. It has composition. Therefore, in the heat dissipation board according to the present invention, the heat dissipation from the board on which the power semiconductor or the like is mounted is more efficiently performed than before, and the power board and the control board are compounded into an integral board. It is possible to improve thermal problems such as heat dissipation.

  In the heat dissipation substrate according to the present invention, the inner surface of the hole is coated with a heat conductor, the conductor is made of metal or the like and the surface is alumite treated, or between the hole and the conductor It is possible to further improve the heat dissipation by arranging a filler and mixing aluminum nitride particles in the filler, or by combining these components as appropriate.

It is a figure showing the general composition of an electric power steering device. It is a sectional side view which shows the example of the thermal radiation board | substrate of this invention. (A) and (C) are perspective views showing an example of the shape of the conductor, and (B) is a half sectional perspective view showing another example of the shape of the conductor. It is a sectional side view which shows the example which provided the coating | cover by a heat conductor on the inner surface of the hole comprised by the board | substrate of this invention. It is a sectional side view which shows the example which comprised the conductor of the board | substrate by this invention with a metal, and comprised the alumite-treated aluminum for the surface. FIG. 6 is a side cross-sectional view showing an example in which the inside of a conductor is made of another heat conductive material having a higher heat conductivity than aluminum such as copper and the like in the configuration shown in FIG. 5; While coating the inside with the heat conductor on the inner surface of the hole of the substrate according to the present invention, the conductor is made of metal, and the surface is made of alumite-treated aluminum. FIG. 6 is a side cross sectional view showing an example in which aluminum nitride particles are mixed in a filler between an inner surface inside a hole of a substrate according to the present invention and a conductor erected inside the hole 120; In addition to coating with the heat conductor on the inner surface of the hole of the substrate according to the present invention, it is a side sectional view showing an example in which aluminum nitride particles are mixed in the filler. In addition to making the surface of the conductor of the board | substrate by this invention into alumite, it is a sectional side view which shows the example which mixed the aluminum-nitride particle | grains in the filler. The coating according to the present invention is coated with a heat conductor on the inner surface of the hole of the substrate, the conductor is made of metal, the surface is made of alumite-treated aluminum, and aluminum nitride particles are further added to the filler. It is a side sectional view showing the example which adopted the composition made to mix. It is a sectional side view which shows the example at the time of forming a hole part using a part of lower surface of the conductor film of the board | substrate by this invention. It is a side sectional view showing an example of a control device which has a heat dissipation board by the present invention. It is a sectional side view of the control device which has two conventional substrates.

  Hereinafter, an embodiment of the present invention will be described by taking a case where the configuration example of the heat dissipation board of the present invention is used for a control device of an electric motor used for an electric power steering device of a vehicle or the like.

  Here, the electric power steering device applies a steering assist force (assist force) to the steering mechanism of the vehicle by the rotational force of the electric motor, and the driving force of the motor is a gear or a belt via the reduction mechanism. The transmission mechanism applies a steering assist force to the steering shaft or the rack shaft. Then, such an electric power steering apparatus (EPS) performs feedback control of a motor current in order to generate a torque of a steering assist force accurately.

  The feedback control is to adjust the voltage applied to the electric motor so that the difference between the steering assist command value (current command value) and the detected value of the electric motor current becomes smaller, and the adjustment of the voltage applied to the electric motor is generally performed. This is performed by adjusting the duty (Duty) of PWM (pulse width modulation) control.

  The general configuration of the above-described electric power steering apparatus will be described with reference to FIG. 1. The column shaft (steering shaft, handle shaft) 2 of the steering wheel 1 is a reduction gear of the reduction mechanism 3, universal joints 4a and 4b, and a pinion rack mechanism 5, through tie rods 6a and 6b, and further connected to steering wheels 8L and 8R via hub units 7a and 7b. Further, the column shaft 2 is provided with a torque sensor 10 for detecting a steering torque of the steering wheel 1 and a steering angle sensor 14 for detecting a steering angle θ, and the motor 20 for assisting the steering force of the steering wheel 1 has a speed reducing mechanism 3. Is connected to the column shaft 2 via a reduction gear (gear ratio n).

  A control unit (ECU), which is a control unit 30 for controlling the electric power steering apparatus described above, is configured with a micro control unit (MCU) as a basic component, and supplied with power from the battery 13 and an ignition key 11 After that, an ignition key signal is input.

  The control device 30 configured as described above calculates the current command value of the assist (steering assist) command based on the steering torque Th detected by the torque sensor 10 and the vehicle speed Vel detected by the vehicle speed sensor 12. The current supplied to the electric motor 20 is controlled by the voltage control command value Vref obtained by compensating the current command value. The steering angle sensor 14 is not essential and may not be provided. It is also possible to obtain a steering angle from a rotational position sensor such as a resolver connected to an electric motor.

  Further, a CAN (Controller Area Network) 50 for exchanging various information of the vehicle is connected to the control device 30, and the vehicle speed Vel can also be received from the CAN 50. The control device 30 is also connected to a non-CAN 51 that transmits and receives communications other than the CAN 50, analog / digital signals, radio waves, and the like.

  Further, in the electric power steering apparatus configured as described above, the heat dissipation board 100 of the present invention provided inside the control device 30 is configured as follows, for example. In the following description, with regard to the same components, the same symbols may be used for those which can adopt other forms, and overlapping descriptions and configurations may be partially omitted. Further, in order to facilitate understanding of the present invention, the size of the electronic component and the heat dissipation board, the ratio between the case of the control device, etc., and the scale of the drawings may be appropriately changed and expressed. .

  FIG. 2 is a side cross-sectional view showing an example of the heat dissipation substrate 100 of the present invention. The heat dissipation substrate 100 of the present invention basically has a substrate 110 on which a circuit (not shown) for mounting various electronic components EC is formed on the component mounting surface 130 side, and the electronic component mounting surface 130 of the substrate 110. A structure in which a heat sink 170 is disposed on the back surface 150 side which is the surface opposite to the side is employed.

  Here, the type of the substrate 110 is not particularly limited, and may be a multilayer substrate. In the above embodiment, an example in which a multilayer substrate is used as the substrate 110 is shown. Since the division such as the component mounting surface side 130 and the back surface 150 thereof is for the convenience of describing the present invention, the area on which the electronic component EC is mounted on both surfaces or any surface on one substrate In such a case, a configuration such as providing the heat sink 170 on the back surface portion of the area as the area on which the electronic component EC is mounted is adopted as one of the surfaces of the electronic component EC. Is also possible.

  Further, the hole portion 120 is provided in the substrate 110 from the back surface 150 side of the substrate 110. The hole 120 is a hole provided from the back surface 150 side of the substrate 110 toward the electronic component mounting surface 130, and the hole 120 is not penetrated on the electronic component mounting surface 130 side. A thin portion T having a thickness sufficient to maintain the strength for maintaining the form for mounting the electronic component EC is formed between the electronic component mounting surface 130 side and the thin film portion T side. Here, one or more holes 120 can be provided depending on the configuration of the substrate and the number and type of electronic components mounted on the substrate.

  Further, the electronic component EC of the electronic component mounting surface 130 is provided so that the hole 120 can efficiently conduct heat generated from the electronic component EC mounted on the electronic component mounting surface 130 side. It is desirable that the hole 120 be formed at a position immediately below the back side of the mounted portion, so to speak, and for the same reason, the hole 120 is a power semiconductor having a particularly large amount of heat generation among the electronic components EC. It is more desirable to form immediately under the like.

  Further, the thin portion T is constituted by the insulator 115 immediately below the conductor film (copper foil etc.) 113 etc. constituting the circuit formed on the electronic component mounting surface 130 side and the other part. The insulator 115 is formed of a resin or the like that constitutes a substrate. Therefore, for the purpose of the present invention, the thickness d of the thin portion T is such that direct thermal conduction is possible between the lower portion of the conductor film 113 or the like such as the copper foil and the inside of the hole portion 120. It is desirable to be configured to be 0. However, if the thickness of the thin portion T is too thin, the strength on the side of the electronic component mounting surface 130 is reduced, which causes problems in the mounting of the electronic component EC. Therefore, the thickness d of the thin portion T can maintain the strength on the side of the electronic component mounting surface 130 for mounting the electronic component EC in combination with the thickness of the conductive film 113, and at the same time, the thickness d It is desirable to make as thin as possible so that the heat generated from the electronic component mounting surface 130 can be efficiently conducted into the hole 120.

  In addition, the opening shape formed on the back surface 150 side of the substrate 110 of the hole 120 has a free shape in accordance with the contact surface shape etc. when the electronic component EC is mounted on the electronic component mounting surface 130. It is possible to adopt. Therefore, the opening shape may be any shape such as a circle or a square, and the hole 120 is a cylindrical space when the opening is circular, and the hole is a square when the opening is square. 120 will form a prismatic space. The opening shape is different from the contact surface shape when the electronic component EC is mounted on the electronic component mounting surface 130 (for example, when the mounting surface of the electronic component is a quadrangle, the opening shape is By making the shape of the hole 120 cylindrical and inscribed in the circular shape, the support of the electronic component EC is carried out by the substrate portion of the circular outer side inscribed in the circle), and the strength around the hole 120 is obtained. It is also possible to reduce the thickness of the thin portion T while maintaining it, and to improve the heat dissipation from the electronic component EC.

  In addition, the heat sink 170 disposed on the back surface 150 side, which is the surface opposite to the electronic component mounting surface 130 side of the substrate 110, has a function to conduct the heat from the substrate 110 to the outside of the substrate 110. It is a thing.

  Therefore, the heat dissipating member 170 can use a heat conductive material such as an elastomer such as a polycarbonate resin containing a metal material and various heat dissipating fillers, and the material is not particularly limited. However, for example, when an FET or the like is mounted as the electronic component EC, the heat dissipating surface of the FET is aluminum or the like, so it is more preferable that the heat conductivity is better than these.

  The heat sink 170 is provided to face the opening of the hole 120 and the like on the back surface 150 side in order to efficiently conduct the heat from the substrate to the outside of the substrate. Therefore, the heat dissipating member 170 is configured to be able to conduct the heat from the electronic component mounting surface 130 to the outside of the substrate through the hole 120. Note that the heat dissipating member 170 can be disposed on all or part of the back surface 150 of the substrate depending on the configuration of the substrate 110 and the circuit formed on the substrate, and the hole 120 and the after-mentioned will be described later. As described above, by providing the conductor 180, it is possible to cooperate with them to efficiently dissipate heat from the electronic component EC mounted on the substrate.

  Moreover, the shape of the said heat sink 170 is fundamentally formed in the said embodiment in the plate shape provided in parallel with the plate surface of the said board | substrate. However, it is desirable that the shape of the heat dissipating member 170 be formed parallel to the plate surface of the substrate 110 on the plate surface side of the back surface side 150 of the substrate 110 to maximize the area when facing each other However, the shape of the thickness and the side not facing the plate surface of the back surface side 150 of the substrate 110 are not limited. Therefore, depending on the inner surface shape and the like of the case where the heat dissipation substrate 100 of the present invention is provided, the whole may be formed into a block shape, or irregularities or the like may be provided on the back surface 150 side of the substrate 100 not facing the plate surface. It does not matter.

  Further, in the present invention, a conductor 180 is provided upright from the heat sink 170 toward the upper surface (the thin portion T side) of the hole 120 inside the hole 120. The conductor 180 is for more efficiently conducting the heat conducted from the electronic component mounting surface 130 to the hole 120 to the heat radiator 170. Therefore, it is also possible to use a heat conductive material such as a metal material such as copper or aluminum, for example, and the conductor 180 is formed at the time of forming the heat dissipating member 170 with the same material as the heat dissipating member 170. What was used may be used, and further, as described later, the surface may be processed into alumite or the like.

  The shape of the conductor 180 can be selected arbitrarily according to the shape of the hole 120 and the like. Therefore, for example, a cylindrical or prismatic shape with the heat dissipating member 170 as the bottom surface, or the bottom surface of the conductor 180 in the shape of a polygon such as a star as shown in a perspective view in FIG. As shown in a half sectional perspective view in 3 (B), a plurality of disc-shaped fins are erected by connecting at the central portion, or as shown in a perspective view in FIG. It is also possible to adopt a shape or the like in which the surface area for heat conduction or heat absorption is increased by, for example, erecting a spiral heat conduction plate around a circular column with the heat sink 170 at the bottom.

  In the present invention, it is also possible to adopt a configuration in which a filler 190 is further provided between the conductor 180 and the inner surface of the hole 120. Although a general heat dissipating material (Thermal Interface Material, TIM) can be used for the filler 190, it is possible to use the heat dissipating material TIM among the heat dissipating material TIM, from the viewpoint of the improvement of the filling property and the buffer property against thermal deformation It is further desirable to use conductive grease or a soft resin material which is relatively easy to deform. Further, the filler 190 secures the insulation between the substrate 110 and the conductor 180 to the radiator 170, and also ensures the insulation between the laminated substrates when the substrate 110 is a laminated substrate. Insulating properties are desirable because of this. Therefore, in the present invention, as described later, it is also possible to mix aluminum nitride particles in the filler.

  In the present invention, by adopting such a filler 190, heat conduction from the inner surface of the hole 120 to the conductor 180 made of the heat conductive material and the like is promoted, and a space for the filler 190 is obtained. Between the conductor 180 and the inner surface of the hole 120, the volume change due to the difference between the coefficient of thermal expansion of the substrate 110 provided with the hole 120 and the coefficient of thermal expansion of the conductor 180, etc. It can be absorbed. Therefore, even if there is a change in dimension due to a difference in thermal expansion coefficient between the components of the substrate 110 and the conductor 180, the change directly affects each other through the filler 190. Therefore, it is possible to prevent the substrate 110 from being affected by deformation, cracking or peeling of the copper foil portion due to expansion of the conductor 180 or the like.

  Further, the filler 190 may be provided not only between the conductor 180 and the hole 120, but also on the entire side of the heat sink 170 facing the substrate 110, whereby the substrate 110 is provided. It is possible to dissipate heat from the heat more efficiently.

  The heat dissipation substrate 100, which is the embodiment of the present invention described above, is a so-called basic type, and in the present invention, each component of the heat dissipation substrate of the present invention is appropriately changed to different configurations as follows. It is also possible to form the heat dissipation substrate.

  For example, the example of the heat dissipation substrate 400 described in FIG. 4 is an example in which the inner surface of the hole 120 formed in the substrate is coated with a coating 125 of a heat conductor.

  The covering portion 125 is configured to cover the entire inner surface of the hole portion 120 along the inner surface, and when a plurality of the hole portions 120 are provided, the back surface 150 side of the substrate 110 is provided. It may be extended so as to further cover between the openings of the plurality of holes 120 in the above. And although there is no limitation in particular in the above-mentioned heat conductor which constitutes the above-mentioned covering part 125, it is also possible to use materials of high thermal conductivity, such as copper, and in such a case, the above-mentioned covering May be processed by plating.

  In the present invention, by applying the coating 125 of the heat conductor to the inner surface of the hole 120 as described above, the heat from the heat-generating electronic component EC is drawn to the hole 120 by the coating 125. It is possible to more efficiently transmit in the external direction where the heat sink 170 and the like are provided. Therefore, it is also possible to more efficiently transfer heat to the conductor 180 provided upright inside the hole 120.

  Similarly, when the configuration in which the filling body 190 is provided inside the hole portion 120 by applying the covering portion 125, the constituent material of the filling body 190 (for example, the above-mentioned thermal conductive grease or the like) And oil etc. can be prevented from infiltrating between the layers and inside of the multilayer substrate 110 and the like. Therefore, it is also possible to stably maintain the function (quality) of the product over a long period of time by eliminating the influence of the corrosion of the substrate 100 and the like.

  Furthermore, the covering portion 125 can impart a certain strength to the inner surface of the hole portion 120. Therefore, the provision of a plurality of holes 120 has an effect of suppressing the reduction in the rigidity of the substrate itself and the occurrence of warpage or the like over the entire surface of the substrate, thereby further reducing the thickness of the thin portion T. It also has effects such as can. Therefore, as described later, it is also possible to set the thickness d of the thin portion T to zero.

  Further, for example, the example of the heat dissipation substrate 500 described in FIG. 5 shows an example in which the conductor 180 constituting the present invention is made of metal and the surface is made of aluminum anodized.

  Here, as described above, the conductor 180 is for more efficiently conducting the heat conducted from the electronic component mounting surface 130 to the hole 120 to the radiator 170. Therefore, the conductor 180 is formed using a heat conductive material such as a metal material, and in the case of the heat dissipation substrate 600 according to the present embodiment, aluminum (including an aluminum alloy) is selected as the metal material. The whole of the conductor 180 is made of aluminum. Further, the surface of the portion of the conductor made of aluminum facing the inner surface of the hole portion 120 is subjected to an alumite treatment.

  The above-mentioned alumite treatment is generally a treatment of forming a layer of an oxide film on the surface of aluminum or its alloy, and such treatment can enhance the corrosion resistance and the wear resistance, as well as heat radiation and absorption efficiency. It is possible to improve

  In the heat dissipating substrate 500 of the present invention, the alumite layer 180A is formed on the surface of the conductor 180 by the alumite treatment in this manner to ensure the electrical insulation and the heat absorption rate of the conductor 180. It is possible to improve and conduct heat to the outside of the substrate 110, and at the same time, to improve the corrosion resistance of the conductor 180. Therefore, when the heat from the heat generating electronic component EC mounted on the surface of the substrate 110 is radiated to the space inside the hole 120 via the inner surface of the hole 120, the alumite layer 180A is As part of the conductor 180 acting as a heat sink, it is possible to efficiently absorb the radiated heat and conduct it to the heat sink 170.

  In the case where the alumite layer 180A is formed on the surface of the conductor 180 as described above, the corrosion of the surface of the conductor 180 is caused by the interaction with the constituent (for example, oil) of the filler 190 described above. It is also possible to prevent occurrence and maintain the quality of the heat dissipation substrate 100 of the present invention for a long period of time.

  As described above, the conductor 180 may be made of the same material as the radiator 170 and formed at the time of molding of the radiator 170, etc., and the surface of the radiator 170 may be used. When aluminum is formed, as shown in FIG. 6 above, the portion of the heat sink 170 facing the substrate is also anodized, and the surface other than the hole portion 120 is also facing the substrate. It is also possible to form the alumite layer 180A and to improve the electrical insulation and heat absorption characteristics.

  The conductor 180 can be configured as in the example of the heat dissipation substrate 600 shown in FIG. That is, after the inside of the conductor 180 is made of another heat conductive material 180C having a higher heat conductivity than aluminum such as copper, the aluminum (including an aluminum alloy) 180B is disposed around the surface (surface side) And the alumite layer 180A is formed by alumite treatment of the surface of the aluminum disposed on the surface side of the conductor 180. As a result, the surface of the conductor 180 is It is also possible to use anodized aluminum. Therefore, even with such a modification, in the heat dissipation substrate of the present invention, it is possible to ensure the insulation of the conductor 180, to improve the heat absorption characteristics, to improve the corrosion resistance, etc. It is possible to further improve the performance of the heat dissipation substrate.

  Further, for example, in the example of the heat dissipation substrate 700 described in FIG. 7, as in the heat dissipation substrate 400 described in FIG. 4, the inner surface of the hole 120 is coated with a heat conductor 125 and As in the heat radiation substrate 500 or 600 described above, an example is shown in which the conductor 180 is made of metal and the surface is made of alumite-treated aluminum.

  Therefore, in the case of the heat dissipation substrate 700, the inner surface of the hole 120 is coated with a heat conductor 125 to prevent penetration of the constituent material of the filler 190 into the substrate 110, and By providing a plurality of the holes 120 by giving a certain strength to the inner surface, there is an effect of suppressing the reduction of the rigidity of the substrate itself and the generation of the warpage etc. over the entire surface of the substrate. The alumite treatment of the surface of 180 improves the absorptivity of the heat by the conductor 180 while ensuring the electrical insulation, and promotes the conduction of heat to the outside of the substrate 110, as well as the above. The effect of improving the corrosion resistance of the conductor 180 is also obtained.

  Also, for example, in the example of the heat dissipation substrate 800 described in FIG. 8, a filler between the inner surface inside the hole 120 formed in the substrate and the conductor 180 provided inside the hole 120 Shows an example in which aluminum nitride grains 191 are mixed.

  The thermal conductivity of the above aluminum nitride is generally about 170 (W / m · k), and follows that of copper (Cu) 398 (W / m · k) and aluminum (Al) 236 (W / m · k) Have a large thermal conductivity. Moreover, although it is possible to use a heat conductive grease etc. for the filler 190, the heat conductivity is generally about 1.0 (W / m · k), and 2.0 to 4. Although there are materials having a high thermal conductivity of 0 (W / m · k), there is a problem that the cost increases if they are used for all of the heat generating electronic parts such as a plurality of FETs mounted on a substrate. The aluminum nitride particles 191 may be granulated in the form of granules by adding a binder to high purity aluminum nitride powder (particle diameter: 2 to 4 μm), and the average particle diameter is about 100 (μm), The mixture between the conductor 180 and the inner surface of the hole 120 together with the filler 190 further improves the thermal conductivity, secures the electrical insulation, and improves the effect of reducing the thermal conductive grease usage. It can be done. The mixing amount of aluminum nitride is preferably about 30 to 50% by volume ratio, but more preferably, the density of aluminum nitride particles is such that aluminum nitride particles are continuously in contact with each other in the thermally conductive grease. good.

  In the present invention, by employing such a filler 190 and aluminum nitride particles 191, heat conduction from the inner surface of the hole 120 to the conductor 180 made of the heat conductive material or the like is promoted, and the filler is also used. By providing a space for 190 between the conductor 180 and the inner surface of the hole 120, the thermal expansion coefficient of the substrate 110 provided with the hole 120 and the coefficient of thermal expansion of the conductor 180 It absorbs the volume change due to the difference. Therefore, as described above, even if there is a change in dimension due to a difference in the thermal expansion coefficient between the components of the substrate 110 and the conductor 180 by interposing the filler 190, such a change is mutually There is no direct influence, and therefore, it is possible to prevent the substrate 110 from being affected by deformation, cracking or peeling of the copper foil portion due to expansion of the conductor 180 or the like. Further, in the present invention, by appropriately mixing the aluminum nitride particles 191 as described above, the heat conduction to the heat sink 170 (heat sink (metal material or the like)) (or directly) via the conductor 180 The conductivity of the holes 120 and the electrical insulation between the conductor 180 and the heat sink 170 (heat sink) are secured, so that the inner surface of the holes 120 of the substrate 110 of the present invention and the conduction are improved. It is also possible to reduce the distance to the body 180 extremely.

  Although the mixing ratio of the aluminum nitride particles 200 to the other heat dissipation material (TIM) constituting the filler 190 is not particularly limited, the insulation ratio of the filler 190 is not limited. It is also possible to appropriately select in consideration of the balance between the form maintenance performance including the hardness and fragility of the filler 190 and the ease of handling while ensuring the properties and the heat dissipation.

  Further, for example, in the example of the heat dissipation substrate 900 described in FIG. 9, in addition to the coating 125 by the heat conductor on the inner surface of the hole 120 as in the substrate 400 described above, the filler 190 described above is nitrided. The example which mixed the aluminum particle 191 is shown.

  Therefore, in the case of the heat dissipation substrate 900, in addition to the effect of the heat dissipation substrate 400 shown in FIG. 4 described above, the mixing of the aluminum nitride particles 191 causes the description of the heat dissipation substrate 800 shown in FIG. It is possible to obtain the same effect.

  That is, as described above, in general, the above-mentioned AlN (aluminum nitride) particles are granulated into granules by adding a binder to high purity aluminum nitride powder (H grade) as a raw material, and the thermal conductivity is In addition to having almost the same characteristics as aluminum, it has high electrical insulation compared to ceramics, and it has the characteristics that it is difficult to thermally deform with a coefficient of thermal expansion similar to that of Si (silicon). , Is the best material to mix in TIM.

  Therefore, the insulation property is secured by mixing the aluminum nitride particles 191 into the filler 190 as described above, and the coating 125 by the heat conductor formed on the inner surface of the hole portion 120 of the substrate 800 of the present invention and It is possible to make the distance to the conductor 180 extremely small. The mixing ratio of the aluminum nitride particles 191 to the other heat dissipation material (TIM) constituting the filler 190 is not particularly limited, but as described above, the insulating property of the filler 190 and It is possible to appropriately select in consideration of the balance with the form maintenance performance including the hardness and fragility of the filler 190 and the ease of handling while ensuring the heat dissipation.

  Therefore, in the present invention, as described above, by mixing the aluminum nitride particles 191 in the filler 190, thermal conduction from the electronic component EC to the conductor 180 and the heat radiator 170 via the filler 190. Can be done more effectively.

Further, for example, in the example of the heat dissipation substrate 1000 described in FIG. 10, in addition to making the surface of the conductor 180 alumite as in the substrate 500 described in FIG. 5 and the substrate 700 described in FIG. An example in which aluminum nitride particles 191 are mixed in the above-mentioned filler 190 is shown. (Here, the description is made using the example of the substrate 700.)
Therefore, in the case of the heat dissipation substrate 1000, the surface of the conductor 180 is alumite treated to improve the absorptivity of heat by the conductor 180 while securing the electrical insulation property, and the outside of the substrate 110. The conduction of heat to the conductor 180 is promoted, and at the same time, the effect of improving the corrosion resistance of the conductor 180 can be obtained, and at the same time, the aluminum nitride particles 191 are mixed in the filler 190 to provide insulation and It is also possible to improve the heat dissipation.

  Further, for example, in the example of the heat dissipation substrate 1100 described in FIG. 11, the coating 125 of a heat conductor is applied to the inner surface of the hole 120 as described above, and the conductor 180 is made of metal and the surface is alumite. It is made of treated aluminum, and further, a structure in which aluminum nitride particles 191 are mixed in the filler 190 is adopted.

  Therefore, in the case of the heat dissipation substrate 1000, the effect by the coating 125 by the heat conductor as described above, the effect by forming the conductor 180 with metal and forming the surface with aluminum anodized, The structure in which the aluminum nitride particles 191 are mixed in the filler 190 is obtained, and as a synergy effect of these, it is possible to further improve the insulation and thermal conductivity, and further improve the reliability and stability of the substrate. It is.

  Therefore, in the present invention, the above-mentioned configuration is appropriately selected in consideration of the use, form, cost and the like of the substrate, and these various forms are cooperated to produce a synergistic effect, which is efficient. It is possible to dissipate heat from the electronic component EC mounted on the substrate, thereby achieving the object of the present invention.

  Next, a configuration example in the case where the thickness of the thin portion T in the present invention is 0 will be described using FIG. In the present invention, when the hole 120 is provided immediately below the electronic component EC mounted on the substrate according to the present invention, a conductor film constituting a circuit formed on the mounting surface 130 side of the electronic component EC ( The thin pressure portion T is configured by the insulator 115 immediately below the copper foil or the like 113 or the like and the other portion. However, depending on the configuration of the present invention, the thickness d of the thin portion T can be set to 0, as shown in FIG. 12 and the following, depending on the configuration of the present invention.

  Here, FIG. 12A is a side cross sectional view showing an example in which the hole 120 is formed by utilizing a part of the lower surface of the conductor film (such as copper foil) 113 immediately below the electronic component EC. (B) forms the hole 120 using a part of the lower surface of the conductor film (copper foil etc.) 113 and covers the inner surface of the hole 120 including the part 120 by the heat conductor It is a side sectional view showing the example which formed the.

  In the present invention, the hole 120 is formed by utilizing a part of the lower surface of the conductor film (copper foil or the like) 113 in consideration of the arrangement and size of the hole 120 and the strength of the entire substrate. As shown in FIG. 12A, it is possible to make the thin pressure part 0. Also, for example, as shown in FIG. 12 (B), a part of the lower surface of the conductor film (such as copper foil) 113 is used on the inner surface of the hole 120 to cover the coating 125 with a heat conductor. When applied, it is also possible to maintain a certain strength by increasing the thickness of the covering portion 125 to a certain extent.

  The example shown in FIG. 12 is the case where the hole 125 is formed by utilizing a part of the lower surface of the conductor film 113 directly below the electronic component EC as described above, but in the present invention, the above-mentioned As described above, the hole 125 is formed by utilizing a part of the lower surface of the conductor film 113 of the substrate 110, and the thickness d of the thin portion T is set to 0, whereby the electronic component mounting surface 130 of the substrate 110 is formed. It is also possible to directly extend the hole 120 to the lower surface of the conductor film 113 which forms the circuit formed on the side, and to further improve the heat dissipation. In the above configuration, in the case where the covering portion 125 is provided, the conductor film 113 and the covering portion 125 may have the same potential, but other adjacent hole portions may be provided. In order to ensure insulation, the covering portion 125 formed in the hole 120 is formed so as to insulate the opening of the hole 120 from the opening of the other hole 120.

  Next, with regard to the heat dissipating substrate of the present invention, as shown in FIG. 13, a configuration example in the case where the heat dissipating substrate 700 of the present invention is incorporated in a control device 1300, and a conventional type of substrate as shown in FIG. Description will be made using the configuration example incorporated in 1400.

  Here, FIG. 13 is an example of the case where the heat dissipation substrate 700 of the present invention is used in a control device 1300 for electric power steering used in a vehicle, and FIG. Shows a side sectional view of the case where the In FIG. 13, the covering portion 125 by the heat conductor is configured to cover the opening portions of the plurality of holes 120 provided in the heat dissipation substrate 700. And although the heat dissipation board 700 of the present invention described with reference to FIG. 7 is used as the above example, the present invention is not limited to this, and any other heat dissipation board according to the present invention may be used similarly. It is possible.

  Further, as described above, FIG. 14 shows an example of the conventional control device 1400 in a side sectional view.

  As shown in FIG. 14, in the conventional control device 1400, the control substrate 1430 and the power substrate 1410 are separately configured, and the control substrate 1430 is disposed on the upper side in the case of the control device 1400. Are disposed on the lower side, and the upper and lower substrates are electrically connected by a multipolar connector 1450 mounted therebetween. The layered structure around the power substrate 1410 disposed in the control device 1400 in this manner is, for example, as shown in FIG. Heat dissipation surface such as FET; Solder layer, 3. Copper foil pattern 4. Insulating layer, 5. Aluminum base substrate 6. TIM layer, 7. It comprised in order of the aluminum die cast 790 grade | etc., Which served as the case of a control apparatus, and a radiator.

  On the other hand, as shown in FIG. 13, the heat dissipating substrate 700 of the present invention is a single heat dissipating substrate 700 in which the control substrate 1430 and the power substrate 1410 as shown in FIG. 14 are combined on one substrate. Is configured as. Then, on the plate surface of the heat dissipation substrate 700, a region where the circuit pattern formed on the conventional control substrate 1430 is formed (the left side of the substrate) and the circuit pattern formed on the power substrate 1410 The formed region (the right side portion of the substrate) is configured. And, in the present invention, the laminated structure around the region corresponding to the portion formed on the power substrate 1410 in the substrate 700 is as follows. Heat dissipation surface such as FET; Solder layer, 3. Copper wiring pattern, 4. Thin portion (thin insulating layer comprising a layer of resin etc.) 5. Coating with a heat conductor, 6. a conductor 180 and a radiator 170 layers provided with an alumite layer 180A on the surface through a filler 190 layer formed by TIM containing aluminum nitride particles; It comprises in order of the aluminum die cast 590 grade | etc., Which combines the case of a control apparatus, and a radiator. Therefore, by adopting the structure of the heat dissipation substrate of the present invention, the heat dissipation from the substrate can be achieved effectively structurally.

  Further, in the substrate 700, a region where the circuit pattern formed on the conventional control substrate 1430 is formed (the left side of the substrate) is formed of the same multilayer substrate as the conventional one. Alternatively, as shown in FIG. 13, electronic components EC may be disposed on both sides of the substrate 110.

  As described above, according to the heat dissipating substrate of the present invention, not only the heat generated by the electronic components mounted on the substrate can be efficiently discharged to the outside, but also from the problem of the heat generation and the like conventionally It is possible to form the circuits formed on the power substrate and the control substrate, which have been separately configured, on a single substrate and to store the circuits as a single substrate in the housing of the control device.

  Therefore, mounting of a multipolar connector or the like for electrical connection between a plurality of substrates is not necessary, and assembly lead time can be shortened, so that the cost can be further reduced, and a thin ECU Since it can be created, the degree of freedom in design is improved, and since mounting components can be mounted on both sides, three-dimensional arrangement inside the control device is also possible, and it is possible to improve noise resistance. doing.

  Therefore, according to the present invention, the substrate on which the power semiconductor or the like is mounted is efficiently dissipated, and as described above, a dedicated substrate (power board) for mounting a power semiconductor or the like that handles high power It is possible to improve the problem of heat dissipation etc. in the case where a control substrate that handles small electric power is combined to form an integrated substrate. The above-described various embodiments are merely examples of the configuration of the present invention, and the present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the present invention. is there.

1 steering wheel 2 column axis (steering shaft, steering wheel axis)
Reference Signs List 3 speed reduction mechanism 4a 4b universal joint 5 pinion rack mechanism 6a 6b tie rod 7a 7b hub unit 8L 8R steering wheel 10 torque sensor 11 ignition key 12 vehicle speed sensor 13 battery 14 steering angle sensor 20 electric motor 30 control device (control unit, ECU)

100 400 500 600 700 800 800 900 1000 1100 Heat dissipation substrate 110 Substrate 113 Conductor film 115 Insulation material 120 Hole 125 Coating portion 130 Electronic component mounting surface 150 Back surface 170 Heat dissipation body 180 Conductor 180 A Alumite layer 180 B Aluminum 180 C Another heat conduction material 190 Filler 191 Aluminum nitride grain 1300 1400 Controller 1410 Power board 1430 Control board 1450 Multipolar connector 1390 1490 Aluminum die casting

EC Electronic component T Thin part d Thin part thickness

Claims (9)

A substrate on which a circuit for mounting an electronic component is formed on the component mounting surface side, and a heat dissipation substrate in which a radiator is disposed on all or part of the back surface side of the substrate on the component mounting surface side,
Providing a hole from the back side of the substrate to the component mounting side;
The hole portion is formed without leaving a thin portion under a conductive film constituting a circuit formed on the component mounting surface side of the substrate without penetrating the substrate on the component mounting surface side of the hole portion. A circle formed so as to face the heat generating electronic component disposed on the component mounting surface side of the substrate via the thin portion, and inscribed in the contact surface shape when the heat generating electronic component is mounted on the substrate Supporting the heat generating electronic component with a cylindrical portion having a shape, wherein the inscribed circular outer substrate portion
Inside the hole, a conductor is provided upright from the heat sink side toward the top surface of the hole,
The conductor has a shape in which a heat conduction plate is erected in a spiral shape around a cylinder having the heat dissipating member as a bottom surface,
A filler is disposed between the inner surface inside the hole and the conductor erected inside the hole,
The filler is mixed with particles of aluminum nitride,
The heat dissipating member is formed as an integral unit parallel to the plate surface on the plate surface side on the back surface side of the substrate,
The heat sink and the conductor are formed of the same material,
A surface of the conductor and a portion of the heat sink facing the substrate are alumite treated aluminum.   The heat dissipation substrate according to claim 1, wherein the inner surface of the hole is coated with a heat conductor.   The heat dissipation substrate according to claim 2, wherein the coating by the heat conductor is copper plating applied to the inner surface of the hole. The heat dissipation substrate according to any one of claims 1 to 3 , wherein the conductor is a heat conductive material made of metal. The heat dissipation substrate according to any one of claims 1 to 4 , wherein the thickness of the thin portion is zero. The heat dissipation substrate according to any one of claims 1 to 5 , wherein the substrate is a multilayer substrate. A heat dissipation board in which a control board is integrated with a dedicated board on which a power semiconductor or the like that handles large electric power for driving a motor or the like is mounted by the heat dissipation board according to any one of claims 1 to 6 . The control apparatus which has a thermal radiation board | substrate of any one of Claims 1 thru | or 7 . An electric power steering apparatus comprising the control device according to claim 8 .

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