JP2018037678A - Heat dissipating board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat dissipation in a board into which a board (power board) having a power semiconductor or the like handling a high power mounted thereon and a control board handling a low power are integrated.SOLUTION: A heat dissipating board 100 has a heat dissipator 170 disposed on a board 110, and a hole 120 which does not penetrate a component mounting surface side of the board 110 is formed to leave a thin part T under a conductive film 113 on the component mounting surface side and a heat-generating electronic component EC of a prism which has a polygonal shape inscribed to a contact surface shape when mounted on the board 110 is disposed on the component mounting surface side of the board 110 via the thin part T. A conductor 180 is stood in the hole 120 from the side of the heat dissipator 170 toward a top surface of the hole 120, and a filler 190 into which particles of aluminum nitride are put is disposed between an inner surface of the hole 120 and the conductor 180 stood in the hole and between the board 110 and the heat dissipator 170. The heat dissipator 170 is formed in parallel with a board surface on the board surface side of the rear side of the board 110 as one body.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat dissipation board on which an electronic component is mounted, and more specifically, provides a hole portion leaving a thin portion from the back side of the electronic component mounting surface of the heat dissipation board toward the electronic component mounting surface side, By inserting a conductor into the hole and filling a filler between the hole and the conductor, the heat from the heat-generating electronic component mounted on the electronic component mounting surface side is reduced. The present invention relates to a heat radiating substrate that can efficiently conduct heat to the back side of the electronic component mounting surface and radiate heat.

  2. Description of the Related Art Conventionally, electronic circuits using power semiconductors that handle large amounts of power, such as inverter circuits and power supply circuits, have been made into dedicated substrates as devices become smaller.

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

  In order to solve the problems as described above, for example, a technique as disclosed in JP 2012-92747 A (Patent Document 1) is disclosed.

  In the inverter-integrated electric compressor, the technique described in Patent Document 1 uses a control circuit board on which a power semiconductor or the like is mounted as a thermally conductive board, and one side of the control circuit board is used as a housing of the control device. The heat dissipating flat surface portion is installed so as to be able to transfer heat, and the other surface of the control circuit board is provided with a heat-generating power semiconductor and an electrical component so as to be able to transfer heat.

  The control circuit board includes a board body made of an insulator and a heat conduction penetrating member made of a good heat conductor that is filled in the thickness direction of the board body. The member has a structure in which one end surface thereof is disposed so as to be able to transfer heat to the heat radiation flat portion, and the power semiconductor and the electric component are disposed on the other end surface so as to be able to transfer heat.

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 penetrating 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. Was required separately.

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

  In addition, for example, in an electric motor control device used for an electric power steering device of a vehicle or the like, there is a high demand for downsizing the device because the device needs to be mounted in the vehicle. However, conventionally, in the control device of the electric power steering device, a control board based on information such as a dedicated board (power board) on which a power semiconductor that handles high power for motor driving and the like is mounted, and a sensor system, etc. The control board that handles small power, such as performing, is configured separately in the control device.

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

  Therefore, in order to reduce the size (thinning) of the control device as described above, it is necessary to combine the two-stage and two-layer substrate as described above into one substrate, but there are many problems to be solved. It was. For example, in the above configuration, since the wiring pattern is formed by etching, the conductor foil is as thin as about 70 μm. Therefore, when configuring a power circuit in which a large current flows, the wiring resistance Was a problem. Moreover, in the said board | substrate, the heat dissipation characteristic was restrict | limited by said insulator layer with a low heat transfer coefficient, and there existed a subject that sufficient heat dissipation performance was not obtained.

  Therefore, the present invention aims to solve the above problems and problems, and efficiently dissipates heat from a substrate on which the power semiconductor or the like is mounted, and as described above, a power semiconductor or the like that handles large power. It is an object to improve problems such as heat dissipation when a dedicated board (power board) that mounts and a control board that handles low power is combined to form an integrated board.

  In order to solve the above-described problems, the present invention provides a substrate on which a circuit for mounting an electronic component is formed on a component mounting surface side, and a heat radiator on all or part of the back surface side of the component mounting surface side of the substrate. The heat dissipation board is provided with a hole portion from the back surface side of the substrate toward the component mounting surface side, and the hole portion does not penetrate the substrate on the component mounting surface side of the hole portion. The conductive film forming the circuit formed on the component mounting surface side of the substrate is formed so as to leave a thin portion below the conductive film, and the exothermic electronic component disposed on the component mounting surface side of the substrate is interposed through the thin portion. And a prismatic shape having a polygonal shape inscribed in the shape of a contact surface when the exothermic electronic component is mounted on the substrate, and the inside of the hole is from the radiator side A conductor is provided upright toward the upper surface of the hole, and the inside of the hole A filler is disposed between the inner surface and the conductor standing on the inner side of the hole, and between the substrate and the radiator, and aluminum nitride grains are mixed into the filler. The heat dissipating board is provided as an integrated body parallel to the plate surface on the back surface side of the substrate.

  Further, the solution to the above problem is that, in the heat dissipation board, the conductor has a shape in which a heat conductive plate is provided in a spiral shape around a cylinder having the heat sink as a bottom surface, or the hole portion The inner surface of the substrate and the substrate surface between the substrate and the radiator are coated with a thermal conductor, or the coating with the thermal conductor is the inner surface of the hole and the A substrate on which a circuit for mounting an electronic component is formed on the component mounting surface side by copper plating applied to the substrate surface between the substrate and the heat sink, and the component mounting surface side of the substrate Is a heat dissipating board in which a heat dissipating body is disposed on all or part of the back surface side, and a hole is provided from the back surface side of the substrate toward the component mounting surface side. Without mounting the board on the component mounting surface side, Formed by leaving a thin part at the bottom of the conductor film constituting the circuit formed on the surface side, and provided so as to face the heat-generating electronic components arranged on the component mounting surface side of the substrate through the thin part A prismatic shape having a polygonal shape inscribed in the shape of a contact surface when the heat-generating electronic component is mounted on the substrate, and the substrate side between the inner surface of the hole and the substrate and the radiator Is coated with a heat conductor, and the coating with the heat conductor is a copper plating applied to the inner surface of the hole, and the inside of the hole is formed from the side of the radiator to the hole. A conductor is provided upright on the upper surface, and the conductor is a shape in which a plurality of disc-shaped fins are coupled at the center, or a prismatic shape having a star-shaped polygon at the bottom, Between the inner surface of the inner side and the conductor standing on the inner side of the hole, and the base A filler is disposed between the radiator and the radiator, and aluminum nitride grains are mixed in the filler, and the radiator is integrally formed parallel to the plate surface on the back surface side of the substrate. The heat dissipation substrate is formed as a thing, or the conductor is a heat conductive material made of metal, or the surface of the conductor and the heat dissipation between the substrate and the heat sink. The body surface is more effectively achieved by being anodized aluminum.

  Further, the solution to the above problem is that the conductor and the heat radiating body are formed integrally, or the thickness of the thin portion is 0, or the substrate is a multilayer substrate. This is achieved more effectively.

  Further, the solution of the above problem is that the power board and the control board are integrated by the heat dissipation board, the control apparatus having the heat dissipation board, or the electric power steering apparatus having the control apparatus, It is achieved more effectively.

  In the present invention, the power board and the control board, which have conventionally been configured as separate boards, are combined on one board (two boards are combined into one board), and the power mounted on the board. A hole is provided in the substrate from the back side of the electronic component mounting surface at a position corresponding to a position immediately below an electronic component that generates heat, such as a semiconductor, and a conductor made of a heat conductive material standing from a radiator is embedded therein. It is configured. Therefore, in the heat dissipation board according to the present invention, heat dissipation from the board on which the power semiconductor or the like is mounted is performed more efficiently than before, and the power board and the control board are combined to form an integrated board. It is possible to improve heat problems such as heat dissipation.

  In the heat dissipation substrate according to the present invention, the inner surface of the hole is provided with a coating with a heat conductor, the conductor is made of a metal or the like, and the surface is anodized, or between the hole and the conductor. It is possible to further improve heat dissipation by arranging a filler and mixing aluminum nitride grains into the filler or by appropriately combining these configurations.

It is the figure which showed the general structure of the electric power steering apparatus. It is a sectional side view which shows the example of the heat sink of this invention. (A), (C) is the perspective view which showed the example of the shape of a conductor, (B) is the semi-sectional perspective view which shows the other example of the shape of a conductor. It is a sectional side view which shows the example which coat | covered with the heat conductor to the inner surface of the hole part 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 the metal, and comprised the surface with the anodized aluminum. FIG. 6 is a side sectional view showing an example in which the inside of the conductor is made of another heat conductive material having a higher heat conductivity than aluminum such as copper in the same configuration as shown in FIG. 5. FIG. 3 is a side sectional view showing an example in which the inner surface of the hole portion of the substrate according to the present invention is coated with a heat conductor, the conductor is made of metal, and the surface is made of anodized aluminum. 5 is a side sectional view showing an example in which aluminum nitride particles are mixed in a filler between an inner surface of a hole portion of a substrate according to the present invention and a conductor standing on the inner side of the hole portion 120. FIG. FIG. 5 is a side sectional view showing an example in which aluminum nitride particles are mixed in the filler in addition to coating the inner surface of the hole portion of the substrate according to the present invention with a heat conductor. FIG. 5 is a side sectional view showing an example in which aluminum nitride particles are mixed in the filler in addition to the surface of the conductor of the substrate according to the present invention being anodized. The inner surface of the hole portion of the substrate according to the present invention is coated with a thermal conductor, the conductor is made of metal, the surface is made of anodized aluminum, and the filler is further made of aluminum nitride particles. It is a sectional side view which shows the example which employ | adopted the structure mixed. It is side sectional drawing 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 sectional side view which shows the example of the control apparatus which has a thermal radiation board | substrate by this invention. It is a sectional side view of the conventional control apparatus which has two board | substrates.

  Embodiments of the present invention will be described below by taking as an example a configuration example of a heat dissipation board of the present invention used in a control device for an electric motor used in an electric power steering device of a vehicle.

  Here, the electric power steering device applies 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 applied to a gear or belt via a speed reduction mechanism. A steering assist force is applied to the steering shaft or the rack shaft by the transmission mechanism. Such an electric power steering device (EPS) performs feedback control of the motor current in order to accurately generate the torque of the steering assist force.

  Such feedback control adjusts the electric motor applied voltage so that the difference between the steering assist command value (current command value) and the electric motor current detection value is small. This is done by adjusting the 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. 5, via tie rods 6a and 6b, and further connected to steered wheels 8L and 8R via hub units 7a and 7b. Further, the column shaft 2 is provided with a torque sensor 10 for detecting the steering torque of the handle 1 and a steering angle sensor 14 for detecting the steering angle θ, and the motor 20 for assisting the steering force of the handle 1 is provided with the speed reduction mechanism 3. Are connected to the column shaft 2 via a reduction gear (gear ratio n).

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

  The control device 30 configured as described above calculates a current command value of an 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 a 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, and the steering angle can be obtained from a rotational position sensor such as a resolver connected to an electric motor.

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

  And in the electric power steering apparatus comprised as mentioned above, the thermal radiation board | substrate 100 of this invention provided in the inside of the said control apparatus 30 is comprised as follows, for example. Note that, in the following description, the same constituent elements that may take other forms are denoted by the same symbols, and overlapping descriptions and configurations may be partially omitted. In order to facilitate understanding of the present invention, the ratio between the size of the electronic component and the heat dissipation board, the case of the control device, and the scale of the drawing may be appropriately changed from the actual ones. .

  FIG. 2 is a side 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 includes 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. The structure which has arrange | positioned the heat radiator 170 to the back surface 150 side which is a surface on the opposite side to the side is employ | adopted.

  Here, the type of the substrate 110 is not particularly limited, and may be a multilayer substrate. In the embodiment, an example in which a multilayer substrate is used as the substrate 110 is shown. The component mounting surface side 130 and the back surface 150 thereof are classified for convenience of explanation of the present invention. Therefore, the electronic component EC is mounted on both surfaces or one surface on one substrate. In such a case, one of the surfaces may be used as a region for mounting the electronic component EC, and the heat dissipating body 170 may be provided on the back surface of the region. Is also possible.

  The substrate 110 is provided with a hole 120 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 side, and the hole 120 does not penetrate through the electronic component mounting surface 130 side. Between the electronic component mounting surface 130 and 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 left. Here, one or a plurality of the hole portions 120 can be provided depending on the configuration of the substrate and the number and type of electronic components mounted on the substrate.

  In addition, the hole 120 has the electronic component EC out of the electronic component mounting surface 130 so that heat from the electronic component EC mounted on the electronic component mounting surface 130 side can be efficiently conducted. It is desirable to form the mounting portion at a position directly below the back side of the mounted portion. Further, for the same reason, the hole 120 is a power semiconductor that generates a particularly large amount of heat among the electronic components EC. It is further desirable to form it immediately below.

  Further, the thin portion T is constituted by the insulator 115 directly below or other than the conductor film (copper foil or the like) 113 constituting the circuit formed on the electronic component mounting surface 130 side. The insulator 115 is made of a resin that constitutes the substrate. Therefore, the thickness d of the thin portion T is, from the meaning of the present invention, d = d = so that direct heat conduction is possible between the portion immediately below the conductor film 113 such as the copper foil and the inside of the hole portion 120. It is desirable to configure it to be zero. However, if the thickness of the thin portion T is too small, the strength on the electronic component mounting surface 130 side is lowered, which hinders the mounting of the electronic component EC. Therefore, the thickness d of the thin portion T can maintain the strength to maintain the form on the electronic component mounting surface 130 side for mounting the electronic component EC together with the thickness of the conductor film 113, and at the same time It is desirable to make it as thin as possible so that heat generated from the electronic component mounting surface 130 side can be efficiently conducted into the hole 120.

  The opening shape of the hole 120 formed on the back surface 150 side of the substrate 110 is a free shape according to the shape of the contact surface when the electronic component EC is mounted on the electronic component mounting surface 130. It is possible to adopt. Therefore, an arbitrary shape such as a circle or a square can be selected as the opening shape. When the opening shape is a circle, the hole 120 is a cylindrical space, and when the opening shape is a square, the hole is a hole. 120 forms a prismatic space. Further, 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, the opening shape is changed when the mounting surface of the electronic component is a square). The shape of the inscribed circle is inscribed, and the shape of the hole 120 is cylindrical, and the electronic component EC is supported by the inscribed circular outer substrate portion). It is also possible to reduce the thickness of the thin portion T while maintaining the heat dissipation from the electronic component EC.

  Further, the heat dissipating body 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 of conducting heat from the substrate 110 to the outside of the substrate 110. Is.

  Therefore, the heat radiator 170 can be made of a heat conductive material such as an elastomer such as a polycarbonate resin containing a metal material or various heat radiation fillers, and the material is not particularly limited. However, for example, when an FET or the like is mounted as the electronic component EC, since the heat dissipation surface of the FET is aluminum or the like, it is more desirable to have a better thermal conductivity than these.

  The radiator 170 is provided facing the opening of the hole 120 on the back surface 150 side in order to efficiently conduct heat from the substrate to the outside of the substrate. Therefore, the heat radiator 170 is configured to be able to conduct heat from the electronic component mounting surface 130 to the outside of the substrate through the hole 120. The heat radiator 170 can be disposed on all or a part of the back surface 150 of the substrate depending on the configuration of the substrate 110 and the circuit formed on the substrate. Thus, by providing the conductor 180, it is possible to efficiently dissipate heat from the electronic component EC mounted on the substrate in cooperation with these.

  The shape of the heat dissipating body 170 is basically formed in a plate shape provided in parallel with the plate surface of the substrate in the embodiment. However, it is desirable that the shape of the heat dissipating body 170 be formed in parallel with the plate surface of the substrate 110 on the plate surface side of the back surface 150 of the substrate 110 to maximize the area when facing each other. However, the thickness and the shape of the side not facing the plate surface of the back surface 150 of the substrate 110 are not limited. Therefore, depending on the shape of the inner surface of the case where the heat dissipation substrate 100 of the present invention is provided, the whole is made into a block shape, or unevenness is provided on the side of the back surface 150 of the substrate 100 that does not face the plate surface. It does not matter.

  Further, in the present invention, the conductor 180 is further provided upright from the heat dissipating body 170 toward the upper surface (the thin portion T side) of the hole 120 inside the hole 120. The conductor 180 is for conducting the heat conducted from the electronic component mounting surface 130 to the hole 120 to the heat radiating body 170 more efficiently. Therefore, for example, the conductor 180 can be a heat conductive material such as a metal material such as copper or aluminum, and is formed together with the heat sink 170 when the heat sink 170 is formed. In addition, the surface may be processed into alumite or the like as will be described later.

  The shape of the conductor 180 can be selected according to the shape of the hole 120 or the like. Therefore, for example, a cylindrical shape or prismatic shape with the radiator 170 as a bottom surface, or a bottom surface of the conductor 180 having a polygonal shape such as a star shape as shown in a perspective view in FIG. As shown in the perspective view of the half cross section in FIG. 3 (B), the fins having a plurality of disk shapes are connected at the central portion, or as shown in the perspective view of FIG. 3 (C). It is also possible to adopt a shape with an increased surface area for heat conduction or heat absorption, such as by erecting a spiral heat conduction plate around a cylinder with the radiator 170 as the bottom surface.

  In the present invention, it is also possible to employ a configuration in which a filler 190 is further provided between the conductor 180 and the inner surface of the hole 120. For the filler 190, a general heat dissipation material (Thermal Interface Material, TIM) can be used. Among the heat dissipation materials TIM, from the viewpoint of improving the filling property and buffering against thermal deformation, It is further desirable to use conductive grease or a soft resin material that is relatively easily deformed. In addition, the filler 190 ensures the insulation between the substrate 110 and the conductors 180 to 170 and the insulation between the laminated substrates when the substrate 110 is a laminated substrate. Therefore, it is desirable to have an insulating property. Therefore, in the present invention, as described later, it is possible to adopt a configuration in which aluminum nitride particles are mixed into 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 or the like is promoted, and a space for the filler 190 is provided. Is provided between the conductor 180 and the inner surface of the hole 120, so that 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 dimensional change 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 the expansion of the conductor 180 or the like.

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

  The above-described heat dissipation substrate 100 according to the embodiment of the present invention described above is a basic form. In the present invention, each component of the heat dissipation substrate of the present invention is appropriately changed to a different configuration as follows. It is also possible to form the heat dissipation substrate.

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

  The covering portion 125 is configured to cover the entire inner surface of the hole portion 120 along the inner surface. When a plurality of the hole portions 120 are provided, the back surface 150 side of the substrate 110 is provided. The plurality of hole portions 120 may be extended so as to further cover the openings. The heat conductor constituting the covering portion 125 is not particularly limited, but it is also possible to use a material having high thermal conductivity such as copper. May be obtained by processing by plating.

  In the present invention, by covering the inner surface of the hole portion 120 with the heat conductor 125, heat from the heat-generating electronic component EC or the like is led out to the hole portion 120 by the cover portion 125. In addition, it is possible to transmit more efficiently in the external direction in which the heat radiating body 170 and the like are provided. Therefore, it is possible to more efficiently conduct heat to the conductor 180 provided upright inside the hole 120.

  Similarly, when a configuration in which the filler 190 is provided inside the hole 120 by applying the covering portion 125 is adopted, the constituent material of the filler 190 (for example, the thermal conductive grease or the like) And oil) can be prevented from penetrating between layers and inside the multilayer substrate 110 and the like. Therefore, it is 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.

  Further, the covering portion 125 can give a certain strength to the inner surface of the hole portion 120. Therefore, the provision of a plurality of the hole portions 120 has an effect of suppressing a reduction in rigidity of the substrate itself and generation of warpage over the entire surface of the substrate, thereby further reducing the thickness of the thin portion T. It also has the effect of being able to. Therefore, as described later, the thickness d of the thin portion T can be set to zero.

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

  Here, as described above, the conductor 180 is for conducting heat conducted from the electronic component mounting surface 130 to the hole 120 to the heat radiator 170 more efficiently. Therefore, the conductor 180 is formed using a heat conductive material such as a metal material. 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 entire conductor 180 is made of aluminum. Further, the surface of the conductor facing the inner surface of the hole 120 of the conductor made of aluminum is anodized.

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

  In the heat dissipation substrate 500 of the present invention, by forming the alumite layer 180A on the surface of the conductor 180 by the alumite treatment as described above, the heat absorption rate by the conductor 180 is ensured while ensuring electrical insulation. It is possible to improve and conduct heat to the outside of the substrate 110, and at the same time, the corrosion resistance of the conductor 180 is improved. Therefore, the alumite layer 180A is formed when 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 through the inner surface of the hole 120. As part of the conductor 180 that functions as a heat sink, the radiated heat can be efficiently absorbed and conducted to the heat radiating body 170.

  In addition, when the alumite layer 180A is formed on the surface of the conductor 180 as described above, corrosion on the surface of the conductor 180 due to the interaction with the constituent material (for example, oil) of the filler 190 described above. Generation | occurrence | production can be prevented and it is also possible to maintain the quality of the thermal radiation board | substrate 100 of this invention over a long period of time.

  In addition, as described above, the conductor 180 may be formed of the same material as the heat radiator 170 when the heat radiator 170 is formed, and the surface of the heat radiator 170 may be used. Is formed of aluminum, as shown in FIG. 6, the portion of the radiator 170 facing the substrate is also alumite-treated, and the surface facing the substrate other than the hole 120 is also formed. It is also possible to form an alumite layer 180A to improve electrical insulation and heat absorption characteristics.

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

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

  Therefore, in the case of the heat radiating substrate 700, the inner surface of the hole 120 is coated with a heat conductor 125 to prevent the constituent material of the filler 190 from penetrating into the substrate 110, and the hole 120 By providing a plurality of the hole portions 120 by giving a certain strength to the inner surface, there is an effect of suppressing a reduction in rigidity of the substrate itself and warpage over the entire surface of the substrate, and at the same time, the conductor By anodizing the surface of 180, it is possible to improve the heat absorption rate by the conductor 180 while ensuring electrical insulation, and to conduct heat to the outside of the substrate 110. The effect of improving the corrosion resistance of the conductor 180 can also be obtained.

  Further, for example, in the example of the heat dissipation substrate 800 illustrated in FIG. 8, a filling body between the inner surface of the hole 120 formed in the substrate and the conductor 180 erected on the inner side of the hole 120. This shows an example in which aluminum nitride grains 191 are mixed.

  The thermal conductivity of aluminum nitride is generally about 170 (W / m · k), followed by copper (Cu) 398 (W / m · k) and aluminum (Al) 236 (W / m · k). And has a large thermal conductivity. The filler 190 can be made of thermally conductive grease or the like, and the thermal conductivity is generally about 1.0 (W / m · k), and is about 2.0 to 4.0. There are also those having a high thermal conductivity of 0 (W / m · k), but there is a problem that the cost increases when used for all heat-generating electronic components such as a plurality of FETs mounted on a substrate, for example. The aluminum nitride grains 191 may be granulated 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). Further, mixing with the filler 190 between the conductor 180 and the inner surface of the hole 120 further improves the thermal conductivity, secures electrical insulation, and improves the effect of reducing the amount of thermally conductive grease used. It can be made. The amount of aluminum nitride to be mixed is an appropriate amount, but is preferably about 30 to 50% by volume, and more preferably the density of aluminum nitride particles is such that the aluminum nitride particles are in continuous contact within the thermal grease. good.

  In the present invention, by adopting such a filler 190 and aluminum nitride grains 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 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 thermal expansion coefficient of the conductor 180 are Absorbs volume changes due to differences. Therefore, as described above, 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 is mutually caused through the filler 190. 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 the expansion of the conductor 180 or the like. Further, in the present invention, by appropriately mixing the aluminum nitride grains 191 as described above, heat conduction to the heat radiator 170 (heat sink (metal material or the like)) via the conductor 180 (or directly). Since the improvement of the rate and the electrical insulation between the hole 120 and the conductor 180 and heat radiator 170 (heat sink) are ensured, the inner surface of the hole 120 of the substrate 110 and the conduction of the substrate 110 of the present invention. It is also possible to make the distance from the body 180 extremely small.

  The mixing ratio of the aluminum nitride grains 200 with the other heat dissipation material (TIM) constituting the filler 190 is not particularly limited, but in combination with the above matters, the insulation of the filler 190 is not limited. It is also possible to make an appropriate selection in consideration of the balance between the form maintenance performance including the hardness and brittleness of the filling body 190 and the ease of handling, etc., while ensuring the properties and heat dissipation.

  Further, for example, in the example of the heat dissipation substrate 900 described in FIG. 9, as in the substrate 400 described above, in addition to coating the inner surface of the hole 120 with the heat conductor 125, the filler 190 described above is nitrided. An example in which aluminum particles 191 are mixed 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 description of the heat dissipation substrate 800 shown in FIG. It is possible to obtain the effect as described above.

  That is, as described above, in general, the AlN (aluminum nitride) grains are granulated in a granular form by adding a binder to a high-purity aluminum nitride powder (H grade), and the thermal conductivity is In addition to having almost the same characteristics as aluminum, it has higher electrical insulation than ceramics, and has the same thermal expansion coefficient as Si (silicon), making it difficult to undergo thermal deformation. It is the best material to mix with TIM.

  Therefore, since the insulating property is ensured by mixing the aluminum nitride grains 191 into the filler 190 as described above, the coating 125 with the heat conductor formed on the inner surface of the hole 120 of the substrate 800 of the present invention, The distance from the conductor 180 can be extremely reduced. The mixing ratio of the aluminum nitride grains 191 with 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 While ensuring heat dissipation, it is possible to select appropriately in consideration of the balance with the form maintenance performance including the hardness and brittleness of the filler 190 and the ease of handling.

  Therefore, in the present invention, as described above, heat conduction from the electronic component EC to the conductor 180 and the heat radiating body 170 through the filler 190 is performed by mixing the aluminum nitride particles 191 in the filler 190. Can be performed more effectively.

Further, for example, in the example of the heat dissipation substrate 1000 shown in FIG. 10, the surface of the conductor 180 is anodized like the substrate 500 shown in FIG. 5 and the substrate 700 shown in FIG. 6. This shows an example in which aluminum nitride grains 191 are mixed in the filler 190 described above. (Here, the example of the substrate 700 is used for explanation.)
Therefore, in the case of the heat dissipation substrate 1000, the surface of the conductor 180 is anodized to improve the heat absorption rate of the conductor 180 while ensuring electrical insulation, and to the outside of the substrate 110. In addition, the effect of improving the corrosion resistance of the conductor 180 can be obtained, and at the same time, the aluminum nitride grains 191 are mixed into the filler 190 to obtain an insulating property. It is also possible to improve heat dissipation.

  Further, for example, in the example of the heat dissipation substrate 1100 described in FIG. 11, the inner surface of the hole portion 120 is coated with the heat conductor 125 as described above, the conductor 180 is made of metal, and the surface thereof is anodized. A structure in which aluminum nitride particles 191 are mixed into the filler 190 is adopted.

  Therefore, in the case of the heat dissipation substrate 1000, as described above, the effect due to the coating 125 with the heat conductor, the effect that the conductor 180 is made of metal, and the surface is made of anodized aluminum, and The structure in which the aluminum nitride grains 191 are mixed into the filler 190 is obtained, and as a synergistic effect thereof, 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-described configuration is appropriately selected in consideration of the use, form, cost, and the like of the substrate, and these various forms work together to produce a synergistic effect. In addition, 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 when the thickness of the thin pressure portion T in the present invention is 0 will be described with reference to FIG. In the present invention, when the hole 120 is provided immediately below the electronic component EC to be mounted on the substrate according to the present invention, the conductor film constituting the circuit formed on the mounting surface 130 side of the electronic component EC ( The thin pressure portion T is constituted by the insulator 115 directly below the copper foil or the like 113 or other portions. However, depending on the configuration of the present invention, the thin portion T can have a thickness d of zero as shown in FIG. 12 and the following.

  Here, FIG. 12A is a side sectional view showing an example in which the hole 120 is formed by using a part of the lower surface of the conductor film (copper foil or the like) 113 immediately below the electronic component EC. In (B), a hole 120 is formed using a part of the lower surface of the conductor film (copper foil or the like) 113, and the inner surface of the hole 120 including that is covered with a heat conductor covering portion 125. It is a sectional side view which shows the example which formed.

  In the present invention, the hole 120 is formed by using 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 or the strength of the entire substrate. As shown in FIG. 12A, the thin pressure portion can be zero. In addition, for example, as shown in FIG. 12B, a part 125 of the lower surface of the conductor film (copper foil or the like) 113 is used on the inner surface of the hole 120 to cover the heat conductor covering portion 125. When applied, it is possible to maintain a certain strength by increasing the thickness of the covering portion 125 to some extent.

  The example shown in FIG. 12 is a case where the hole 125 is formed by using a part of the lower surface of the conductor film 113 directly below the electronic component EC as described above. As described above, the hole 125 is formed using 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 reach the hole 120 directly to the lower surface of the conductor film 113 constituting the circuit formed on the side, and further improve the heat dissipation. In addition, when it is set as the structure which provides the coating | coated part 125 among such a structure, although the said conductor film 113 and the said coating | coated part 125 can be made into the same electric potential, it is with other adjacent hole parts. In order to ensure the insulation, the covering portion 125 formed in the hole portion 120 is formed so that the opening portion of the hole portion 120 is insulated from the opening portions of the other hole portions 120.

  Next, with respect to the heat dissipation substrate of the present invention, a configuration example in which the heat dissipation substrate 700 of the present invention is incorporated in the control device 1300 as shown in FIG. 13 and a conventional substrate as shown in FIG. A description will be given using a configuration example incorporated in 1400.

  Here, FIG. 13 shows an example in which the heat dissipation board 700 of the present invention is used in an electric power steering control device 1300 used in a vehicle. FIG. 13 shows the heat dissipation substrate 1100 in the case of the control device 1300. The sectional side view at the time of storing is shown. In FIG. 13, the covering portion 125 made of the heat conductor is configured to cover the openings of the plurality of holes 120 provided in the heat dissipation substrate 700. And as said example, although the thermal radiation board | substrate 700 of this invention demonstrated regarding FIG. 7 is used, not only this but the thing of another structure can be used similarly if it is a thermal radiation board | substrate by this invention. Is possible.

  FIG. 14 is a side sectional view showing an example of a conventional control device 1400 as described above.

  As shown in FIG. 14, in the conventional control device 1400, the control board 1430 and the power board 1410 are configured separately, and the control board 1430 is arranged on the upper side in the case of the control apparatus 1400, and the power board 1410. Are arranged on the lower side, and the upper and lower substrates are electrically connected by a multipolar connector 1450 mounted therebetween. And the laminated structure around the power board 1410 arranged in the control device 1400 in this way is, for example, from the top in FIG. 1. Heat dissipation surface of FET, etc. 2. solder layer; Copper foil pattern, 4. 4. insulating layer; Aluminum base substrate, 6. TIM layer, 7. An aluminum die cast 790 that also serves as a case for the control device and a radiator was formed in this order.

  On the other hand, as shown in FIG. 13, the heat dissipation board 700 of the present invention is a single heat dissipation board 700 in which the control board 1430 and the power board 1410 as shown in FIG. 14 are combined on one board. It is configured as. On the plate surface of the heat dissipation substrate 700, there are a circuit pattern formed on the power substrate 1410 and a region where the circuit pattern formed on the conventional control substrate 1430 is formed (the left portion of the substrate). A formed region (a right side portion of the substrate) is formed. In the present invention, the laminated structure around the region corresponding to the portion formed on the power substrate 1410 of the substrate 700 is as follows. 1. Heat dissipation surface of FET, etc. 2. solder layer; 3. Copper wiring pattern 4. Thin portion (thin insulating layer made of a resin layer), 5. Cover portion with heat conductor, 6. Conductor 180 and heat dissipating body 170 layer having an alumite layer 180A provided on the surface through a filler 190 layer formed of TIM containing aluminum nitride grains; It is comprised in order of the aluminum die-casting 590 etc. which serve as the case of a control apparatus, and a heat radiator. Therefore, by adopting the structure of the heat dissipation substrate of the present invention, heat dissipation from the substrate can be achieved structurally and effectively.

  In addition, in the substrate 700, a region where the circuit pattern formed on the conventional control substrate 1430 is formed (the left portion of the substrate) is configured by a multilayer substrate similar to the conventional one. As shown in FIG. 13, it is also possible to adopt a configuration in which electronic components EC are arranged on both surfaces of the substrate 110.

  As described above, according to the heat dissipation board of the present invention, it is possible not only to efficiently discharge the heat generated by the electronic components mounted on the board to the outside, but also due to the above-described problem of heat generation. Circuits formed on the power board and the control board, which have been configured separately, can be formed on a single board and stored as a single board in the housing of the control device.

  This eliminates the need for mounting a multi-pole connector for electrical connection between a plurality of substrates, shortens the assembly lead time, etc., and can further reduce the cost of the thin ECU. Since it can be created, the degree of freedom of design is improved, and the mounting parts can be mounted on both sides, so that it can be arranged in three dimensions inside the control unit, and it has the advantage of improving noise resistance. doing.

  Therefore, according to the present invention, a dedicated substrate (power substrate) for efficiently dissipating heat from the substrate on which the power semiconductor or the like is mounted and mounting a power semiconductor or the like that handles large power as described above is provided. It is possible to improve problems such as heat dissipation when a control board that handles low power is combined to form an integrated board. In addition, since the various embodiments described above show examples of the configuration of the present invention, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the gist of the present invention. is there.

1 Handle 2 Column shaft (steering shaft, handle shaft)
DESCRIPTION OF SYMBOLS 3 Deceleration 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 Conductive film 115 Insulating material 120 Hole portion 125 Cover portion 130 Electronic component mounting surface 150 Back surface 170 Heat dissipator 180 Conductor 180A Anodized layer 180B Aluminum 180C Another heat conductive material 190 Filler 191 Aluminum nitride grains 1300 1400 Controller 1410 Power board 1430 Control board 1450 Multipolar connector 1390 1490 Aluminum die-cast

EC electronic component T Thin part d Thin part thickness

Claims (13)

A substrate on which a circuit for mounting an electronic component is formed on the component mounting surface side, and the component mounting surface side of the substrate is a heat dissipation substrate in which a heat radiator is disposed on all or part of the back surface side,
A hole is provided from the back surface side of the substrate toward the component mounting surface side,
The hole portion does not penetrate the substrate on the component mounting surface side of the hole portion, and forms a thin portion at a lower portion of a conductor film constituting a circuit formed on the component mounting surface side of the substrate, A polygon that is provided so as to be opposed to the heat-generating electronic component disposed on the component mounting surface side of the substrate via the thin portion, and is inscribed in a contact surface shape when the heat-generating electronic component is mounted on the substrate. A prismatic shape having a shape,
Inside the hole, a conductor is provided upright from the radiator side toward the upper surface of the hole,
Between the inner surface of the inner side of the hole and the conductor erected on the inner side of the hole, and between the substrate and the radiator, a filler is disposed,
Aluminum filler grains are mixed in the filler,
The heat dissipating board is formed as an integrated body parallel to the plate surface on the back surface side of the substrate.   The heat radiating substrate according to claim 1, wherein the conductor has a shape in which a heat conductive plate is erected in a spiral shape around a cylinder having the heat radiating body as a bottom surface.   The heat dissipation substrate according to claim 1 or 2, wherein the inner surface of the hole portion and the substrate surface between the substrate and the heat dissipation body are coated with a heat conductor.   The heat dissipation substrate according to claim 3, wherein the coating with the heat conductor is copper plating applied to an inner surface of the hole and a substrate surface between the substrate and the heat dissipation body. A substrate on which a circuit for mounting an electronic component is formed on the component mounting surface side, and the component mounting surface side of the substrate is a heat dissipation substrate in which a heat radiator is disposed on all or part of the back surface side,
A hole is provided from the back surface side of the substrate toward the component mounting surface side,
The hole portion does not penetrate the substrate on the component mounting surface side of the hole portion, and forms a thin portion at a lower portion of a conductor film constituting a circuit formed on the component mounting surface side of the substrate, A polygon that is provided so as to be opposed to the heat-generating electronic component disposed on the component mounting surface side of the substrate via the thin portion, and is inscribed in a contact surface shape when the heat-generating electronic component is mounted on the substrate. A prismatic shape having a shape,
The inner surface of the hole and the substrate side between the substrate and the radiator are coated with a thermal conductor, and the coating with the thermal conductor is made of copper plating applied to the inner surface of the hole. Yes,
Inside the hole, a conductor is provided upright from the radiator side toward the upper surface of the hole,
The conductor is a shape in which a plurality of disk-shaped fins are combined at the center, or a prismatic shape having a star-shaped polygonal bottom.
Between the inner surface of the inner side of the hole and the conductor erected on the inner side of the hole, and between the substrate and the radiator, a filler is disposed,
Aluminum filler grains are mixed in the filler,
The heat dissipating board is formed as an integrated body parallel to the plate surface on the back surface side of the substrate.   The heat radiating substrate according to claim 1, wherein the conductor is a heat conductive material made of metal.   The heat radiating substrate according to claim 6, wherein the surface of the conductor and the surface of the heat radiating member between the substrate and the heat radiating member are anodized aluminum.   The heat radiating substrate according to claim 1, wherein the conductor and the heat radiating body are integrally formed.   The heat dissipation board according to any one of claims 1 to 8, wherein the thin portion has a thickness of 0.   The heat dissipation substrate according to claim 1, wherein the substrate is a multilayer substrate.   A heat dissipation board obtained by integrating a control board and a dedicated board on which a power semiconductor or the like that handles high power for motor driving or the like is integrated with the heat dissipation board according to any one of claims 1 to 10.   The control apparatus which has a thermal radiation board of any one of Claims 1 thru | or 11. An electric power steering device comprising the control device according to claim 12.

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