JP6616166B2 - Circuit board and electronic device - Google Patents

Description

  The present invention relates to a circuit board having a metal plate and an electronic device.

2. Description of the Related Art Conventionally, as a circuit board used in an electronic device on which an electronic component such as an IGBT (Insulated Gate Bipolar Transistor) is mounted, a circuit board in which a metal plate is bonded to an upper surface of an insulating substrate made of a ceramic sintered body or the like is used. ing.

  The metal plate of the circuit board forms a circuit for electrically connecting the electronic component to an external electric circuit. Electronic devices mounted on the circuit board are electrically connected to a metal plate to produce an electronic device. At this time, the electronic component is covered with a covering material such as a resin material. In such an electronic device, an electronic component and an external electric circuit are electrically connected to each other through a metal plate.

  In addition, a circuit board having a structure in which another metal plate and another insulating board are sequentially laminated on the lower surface of the insulating board is also used for improving heat dissipation to the outside (for example, patents). Reference 1).

JP 2003-86747 A

  The circuit board and the electronic device according to the prior art have a problem that it is difficult to improve the reliability of sealing of the electronic component by the resin material. In other words, the entire circuit board is likely to warp due to thermal stress generated between the insulating substrate made of a ceramic sintered body or the like and the metal plate, and this warp creates a gap between the circuit substrate and the resin material. There was a possibility that the reliability of the would decrease.

A circuit board according to one aspect of the present invention includes a first ceramic plate having an upper surface including a region in which a first metal plate is disposed, and a second ceramic plate having a lower surface including a region in which the second metal plate is disposed. A third metal plate that is disposed between the lower surface of the first ceramic plate and the upper surface of the second ceramic plate and is thicker than any of the first metal plate and the second metal plate. Each side surface of the first ceramic plate and the second ceramic plate is located outside the side surface of the third metal plate, and the first metal plate is a first metal plate for a control signal. And the first metal plate for large current that is larger than the control signal, and the upper surface of the third metal plate has a top end of the side surface of the first current metal plate 3 for large current in plan view. It has a recess which is located outside the side surface And wherein the door.

  An electronic device according to an aspect of the present invention includes a circuit board having the above-described configuration, an electronic component mounted on the first metal plate, and integrally covering from the electronic component to a side surface of the second ceramic plate. And a mold resin.

  According to the circuit board of one aspect of the present invention, because of the above configuration, the third metal plate that is thicker than the first metal plate and the second metal plate and has a relatively large rigidity is the first ceramic plate and the second metal plate. Since it is disposed between two ceramic plates, it is advantageous for improving the rigidity of the entire circuit board. That is, it is effective for reducing warpage of the entire circuit board.

Further, the side surface of the circuit board is stepped due to the difference in position between the side surfaces of the first ceramic plate and the second ceramic plate and the side surface of the third metal plate. The step-shaped side surface is formed by projecting the first ceramic plate and the second ceramic plate having a relatively high bonding strength to the resin material to the outside. Therefore, the bonding area between the mold resin containing the resin material and the circuit board (especially the first ceramic plate and the second ceramic plate) is larger than that in the conventional case at the side surface portion of the circuit board, that is, the portion where the thermal stress acts more. can do. Further, the joint surface between the mold resin and the circuit board on the side surface is not a simple plane but an intricate shape. As a result, the bonding strength between the mold resin and the circuit board can be made higher than before. Therefore, it is possible to provide a circuit board in which the possibility that a gap is generated between the molded resin and the electronic component to be mounted is reduced.

  In addition, since the upper surface of the third metal plate has the recess as described above, the distance between the upper end of the side surface of the recess and the side surface of the first metal plate is sufficiently large, and the first metal plate and the third metal plate The breakdown voltage between the metal plate is effectively increased.

  In addition, according to the electronic device of one aspect of the present invention, the electronic component with high reliability of sealing of the electronic component in which peeling between the mold resin covering the mounted electronic component and the circuit board is suppressed. An apparatus can be provided.

(A) is sectional drawing which shows the circuit board of the 1st Embodiment of this invention, (b) is sectional drawing which shows the electronic device of embodiment of this invention. (A) is an expanded sectional view which expands and shows the principal part of FIG. 1 (a), (b) is an expanded sectional view which shows the modification of (a). (A) is sectional drawing which shows the 1st modification of the circuit board and electronic device which are shown in FIG. 1, (b) is sectional drawing which shows a 2nd modification. (A) is a top view which shows the circuit board of the 2nd Embodiment of this invention, (b) is sectional drawing in the AA of (a). (A) is an expanded sectional view which expands and shows the principal part of FIG.4 (b), (b) and (c) are expanded sectional views which show the modification of (a). It is a top view which shows the modification of the circuit board shown in FIG. (A) is a top view which shows the other modification of the circuit board shown in FIG. 4, (b) is sectional drawing in the AA of (a). (A) is a top view which shows the other modification of the circuit board shown in FIG. 4, (b) is sectional drawing in the AA of (a).

  The circuit board and electronic device of the present invention will be described below with reference to the drawings. In addition, the distinction between the upper and lower sides in the following description is for convenience, and does not limit the upper and lower sides when the circuit board and the electronic device are actually used.

  A circuit board 20 and an electronic device 30 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1A is a cross-sectional view of a mounting body (without reference numerals) in which an electronic component 6 is mounted on a circuit board 20 according to an embodiment of the present invention, and FIG. 1B is a mounting body shown in FIG. 3 is a cross-sectional view showing an electronic device 30 covered with a mold resin 8. FIG. FIG. 2A is an enlarged cross-sectional view showing an example of a B portion which is a main part of FIG. 1, and FIG. 2B is an enlarged cross-sectional view showing a modification of FIG. 2A.

The circuit board 20 has a flat plate-like first ceramic plate 1 and second ceramic plate 2 as insulator portions. The first metal plate 3 is disposed with the lower surface superimposed on the upper surface of the first ceramic plate 1, and the second metal plate 4 is disposed with the upper surface superimposed on the lower surface of the second ceramic plate 2. A third metal plate 5 is disposed between the lower surface and the upper surface of the second ceramic plate 2. That is, the second metal plate 4 and the second ceramic plate 2 which are sequentially laminated from the lower side.
The circuit board 20 of the embodiment is basically constituted by the third metal plate 5, the first ceramic plate 1 and the first metal plate 3.

  The first ceramic plate 1 and the second ceramic plate 2 are made of a ceramic material such as a silicon nitride sintered body, as will be described later. Moreover, the 1st metal plate 3, the 2nd metal plate 4, and the 3rd metal plate 5 consist of metal materials, such as copper, so that it may mention later.

  In addition, the electronic component 6 is mounted on the first metal plate 3 of the circuit board 20, and the electronic component 6 and the first metal plate 3 are electrically connected by a bonding wire 7 or the like. The electronic device 30 is manufactured by covering the side surface of the ceramic plate 2 with the mold resin 8. That is, the electronic device 30 according to the embodiment of the present invention includes the circuit board 20 having the above-described configuration, the electronic component 6 mounted on the first metal plate 3, and the electronic component 6 to the first metal plate 3 and the first ceramic plate. 1 and the mold resin 8 that integrally covers the side surface of the second ceramic plate 2 beyond the side surfaces of the first ceramic plate 1 and the third metal plate 5.

  In the example shown in FIG. 1B, the mold resin 8 covers the side surface of the second metal plate 4 beyond the side surface of the second ceramic plate 2. In other words, in the electronic device 30 of this embodiment, only the lower surface of the second metal plate 4 is not covered with the mold resin 8 and is exposed to the outside.

  In the circuit board 20 of the embodiment, the third metal plate 5 is thicker than both the first metal plate 3 and the second metal plate 4. Further, the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 are located outside the side surfaces of the third metal plate 5 in plan view.

  According to the circuit board 20 of such an embodiment, because of the above configuration, the third metal plate 5 which is thicker than the first metal plate 3 and the second metal plate 4 and has relatively high rigidity is the first ceramic. Arranged between the plate 1 and the second ceramic plate 2. For this reason, since the rigidity of the circuit board 20 as a whole is higher than the conventional one, the warp of the circuit board 20 can be easily reduced.

  Further, the side surface of the circuit board 20 is stepped due to the difference in position between the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 and the side surface of the third metal plate 5. Further, the stepped side surface is formed by the first ceramic plate 1 and the second ceramic plate 2 having a relatively high bonding strength to the resin material projecting outward. Therefore, the bonding area between the resin material of the mold resin 8 and the circuit board 20 (particularly, the first ceramic plate 1 and the second ceramic plate 2) is the side part of the circuit board 20, that is, the part where thermal stress acts more. Is larger than before. Further, the joint surface between the mold resin 8 and the circuit board 20 on the side surface is not a simple flat surface but an intricate shape. Due to such a form of the bonding surface, the bonding strength between the mold resin 8 and the circuit board 20 is higher than the conventional one. Accordingly, the circuit board 20 is less likely to be peeled off from the mold resin 8 and the circuit board 20 due to the warp of the circuit board 20, coupled with the fact that the warpage of the circuit board 20 can be easily reduced.

  Further, an apparent thermal expansion coefficient, which will be described later, of the circuit board 20 having the relatively thick third metal plate 5 is assumed to be a third metal plate (not shown) having the same thickness as the first metal plate 3 and the second metal plate 4. It is larger than the apparent thermal expansion coefficient. This is because the influence of the thermal expansion and contraction of the relatively thick third metal plate 5 on the circuit board 20 is larger than that of the prior art. Since the apparent thermal expansion coefficient of the circuit board 20 is large and approaches the thermal expansion coefficient of the mold resin 8 (such as epoxy resin described later), the difference in thermal expansion coefficient between the circuit board 20 and the mold resin 8 itself (thermal stress) Itself) can also be made smaller.

Therefore, it is possible to provide the circuit board 20 in which the possibility that a gap is generated between the molded resin 8 that covers the electronic component 6 to be mounted is reduced.

  Further, according to the electronic device 30 of the embodiment as described above, the sealing of the electronic component 6 in which peeling between the mold resin 8 covering the mounted electronic component 6 and the circuit board 20 is suppressed. The highly reliable electronic device 30 can be provided.

  The distances A1 and A2 between the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 and the side surfaces of the third metal plate 5, that is, the first ceramic plate 1 in the direction along the lower surface of the first ceramic plate 1 The distance A1 between the side surface of the second ceramic plate 2 and the side surface of the third metal plate 5 and the distance A2 between the side surface of the second ceramic plate 2 and the side surface of the third metal plate 5 in the direction along the upper surface of the second ceramic plate 2 are Difference in thermal expansion coefficient between the ceramic plate 1 and the second ceramic plate 2 and the first metal plate 3, the second metal plate 4 and the third metal plate 5 (that is, thermal expansion between the insulator portion and a metal material such as copper) The difference is set as appropriate according to the conditions such as the difference in the coefficient and the material of the mold resin 8.

  For example, the first ceramic plate 1 and the second ceramic plate 2 are made of a silicon nitride sintered body, each having a thickness of about 0.32 mm, and there is a difference in thermal expansion coefficient between the insulator portion and a metal material such as copper. If the mold resin 8 is made of an epoxy resin, the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 and the side surfaces of the third metal plate 5 are about 8 to 14 × 10 −6. The distance between them may be set to 0.05 to 0.48 mm.

  The distances A1 and A2 between the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 and the side surface of the third metal plate 5 may be set to about 0.05 to 0.48 mm, for example. The distances A1 and A2 between the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 and the side surfaces of the third metal plate 5 are the same as in the example shown in FIG. And a virtual plane extending from the side surface of the second ceramic plate 2 in the direction of the third metal plate 5 and a portion of the third metal plate 5 joined to the first ceramic plate 1 or the second ceramic plate 2. It means the distance between the outermost part (the part at the position corresponding to the side surface of the third metal plate 5). Note that the position of the virtual plane is shown by a solid line in FIG. 2 for easy viewing.

  If the distance A1 between the side surface of the first ceramic plate 1 and the third metal plate 5 and the distance A2 between the side surface of the second ceramic plate 2 and the side surface of the third metal plate 5 are 0.05 mm or more, A space for forming the fillet of the brazing material 10 is effectively ensured from the lower surface of the first ceramic plate 1 and the upper surface of the second ceramic plate 2 to the side surface of the third metal plate 5. Therefore, stress can be effectively dispersed in the brazing material 10. That is, the stress applied to the first ceramic plate 1 and the second ceramic plate 2 at the outer peripheral position of the side surface of the third metal plate 5 is reduced. As a result, mechanical breakage due to stress concentration of the first ceramic plate 1 and the second ceramic plate 2 itself is also effectively suppressed. Further, when the distance between the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 and the side surface of the third metal plate 5 is 0.48 mm or less, the circuit board 20 and the electronic device 30 can be downsized. Is advantageous.

  The first ceramic plate 1 and the second ceramic plate 2 are made of an electrically insulating material. Examples of the electrical insulating material include ceramic materials such as aluminum oxide ceramics, mullite ceramics, silicon carbide ceramics, aluminum nitride ceramics, and silicon nitride ceramics. Among these ceramic materials, silicon carbide ceramics, aluminum nitride ceramics, and silicon nitride ceramics are higher in terms of thermal conductivity that affects heat dissipation. In terms of mechanical strength, silicon nitride ceramics and silicon carbide ceramics are higher.

When the first ceramic plate 1 and the second ceramic plate 2 are made of a ceramic material having a relatively high mechanical strength such as silicon nitride ceramics, thermal expansion with the first metal plate 3 and the second metal plate 4 is performed. The possibility of mechanical destruction such as generation of cracks in the first ceramic plate 1 and the second ceramic plate 2 due to thermal stress caused by the coefficient difference is reduced.

The thicknesses of the first ceramic plate 1 and the second ceramic plate 2 are, for example, about 0.1 mm to 1 mm, and can be appropriately set according to conditions such as predetermined external dimensions and mechanical strength of the circuit board 20 and the electronic device 30. Good.

  If the first ceramic plate 1 and the second ceramic plate 2 are made of, for example, silicon nitride ceramics, they can be produced by the following method. First, a suitable organic binder, plasticizer and solvent are added to and mixed with raw material powders such as silicon nitride, aluminum oxide, magnesium oxide and yttrium oxide to form a slurry. Next, the slurry is processed into a sheet shape by a molding method such as a doctor blade method or a calender roll method to produce a ceramic green sheet (ceramic green sheet). Next, the ceramic green sheet is subjected to an appropriate punching process or the like and formed into a predetermined shape, and a plurality of sheets are laminated as necessary to produce a laminate. Thereafter, this laminate (ceramic green sheet) is fired at a temperature of about 1600 to 2000 ° C. in a non-oxidizing atmosphere such as a nitrogen atmosphere. Through the above steps, the first ceramic plate 1 and the second ceramic plate 2 can be manufactured.

  The first metal plate 3 functions as a part of a conductive path that electrically connects the electronic component 6 mounted on the circuit board 20 to an external electric circuit (not shown). In the example shown in FIG. 1, a plurality of first metal plates 3 are joined to the upper surface of the first ceramic plate 1. Each first metal plate 3 forms, for example, an electrically independent circuit, and as described above, different electrodes (not shown) of the electronic component 6 are electrically connected by the bonding wires 7 or the like. Yes. Different electrodes of the electronic component 6 are, for example, electrodes for a large current and a control signal.

  The electronic component 6 is joined to the first metal plate 3 by a so-called low melting point brazing material (no symbol) such as a tin-silver solder or a gold-silicon brazing material. A low melting point brazing film or paste or the like is placed in advance on a predetermined portion of the upper surface of the first metal plate 3, and the lower surface of the electronic component 6 is aligned and set in that portion and brazed by heating. . Thus, the electronic component 6 is joined to the first metal plate 3. The electronic component 6 is electrically connected to the first metal plate 3 as described above, and the electronic component 6 is mounted on the circuit board 20.

  The bonding wire 7 is, for example, a so-called gold wire or aluminum wire, and one end portion is connected to the electronic component 6 and the other end portion is connected to a predetermined portion of the first metal plate 3.

  The first metal plate 3 is formed of a metal material such as copper or aluminum, for example. Moreover, the 1st metal plate 3 may be formed with the metal material of the alloy which has copper or aluminum as a main component. If the first metal plate 3 is made of, for example, copper, the copper plate material is subjected to metal processing such as cutting, rolling, or etching to be processed into a predetermined shape and dimensions as the first metal plate 3. Can be produced.

The second metal plate 4 functions as, for example, a heat dissipation material for radiating heat to the outside. For example, if the lower surface of the second metal plate 4 is joined to a heat dissipation material (not shown), heat is conducted from the second metal plate 4 to the heat dissipation material, and heat is effectively dissipated from the heat dissipation material to the outside. . This heat is generated with the operation of the electronic component 6 mounted on the circuit board 20. Heat generated in the electronic component 6 is sequentially transmitted through the first metal plate 3, the first ceramic plate 1, the third metal plate 5, and the second ceramic plate 2 to be conducted to the second metal plate 4. That is, in this case, a heat transfer path is formed from the electronic component 6 (the first metal plate 3 on which the electronic component 6 is mounted) to the second metal plate 4 to dissipate the heat generated in the electronic component 6 to the outside. The

  The second metal plate 4 can also function as a terminal for electrical connection to an external electric circuit. In this case, if the lower surface of the second metal plate 4 is joined so as to face a predetermined portion of the external electric circuit, the circuit board 20 and the electronic device 30 are electrically connected to the external electric circuit via the second metal plate 4. Connection is made. This electrical connection is made, for example, to set the second metal plate 4 to the ground potential.

  The second metal plate 4 can also be manufactured in the same manner using the same material as the first metal plate 3. The second metal plate 4 has a relatively large area in plan view as compared with the first metal plate 3 in a plurality of divided forms in consideration of heat dissipation or ground potential stability. It is desirable to arrange.

  The third metal plate 5 is thicker than both the first metal plate 3 and the second metal plate 4. The third metal plate 5 forms part of the heat transfer path from the electronic component 6 (the first metal plate 3 on which the electronic component 6 is mounted) to the second metal plate 4. The heat conducted from the first metal plate 3 through the first ceramic plate 1 is conducted by the third metal plate 5 having a relatively large thickness while being effectively spread not only in the downward direction but also in the lateral direction. Further, since the third metal plate 5 has a relatively large volume, the heat capacity is relatively large. The third metal plate 5 has a high thermal conductivity like the first metal plate 3 and the second metal plate 4, like copper or an alloy containing copper as a main component, or aluminum or an alloy containing aluminum as a main component. It is made of a metal material. Therefore, the heat generated in the electronic component 6 is efficiently conducted to the third metal plate 5 through the heat transfer path.

  As described above, the thermal conductivity between the first ceramic plate 1 and the first metal plate 3 and the second ceramic plate 2 and the second metal plate 4 is effectively increased. Thus, the circuit board 20 capable of manufacturing the electronic device 30 having excellent heat dissipation can be obtained, and by providing the circuit board 20, the electronic device 30 having excellent heat dissipation can be provided.

  Further, as described above, since the third metal plate 5 has a relatively large thickness and a relatively large rigidity, the third metal plate 5 increases the rigidity as the circuit board 20 and the electronic device 30 and makes it difficult to warp the circuit board 20. It has a function.

If the thickness of the 3rd metal plate 5 is a case where it consists of copper, for example, what is necessary is just to set to about 0.5-10 mm thicker than any of the thickness of the 1st metal plate 3 and the 2nd metal plate 4. FIG. The third metal plate 5 may be thicker than the combined thickness of the first metal plate 3 and the second metal plate 4. In this case, the apparent thermal expansion coefficient of the circuit board 20 of the embodiment is an apparent thermal expansion coefficient of a circuit board (not shown) when a single plate of a silicon nitride sintered body is used as an insulating substrate. Larger than the thermal expansion coefficient of the mold resin 8. That is, the stress resulting from the difference between the thermal expansion coefficients of the two becomes smaller.

  The third metal plate 5 can also be manufactured in the same manner using the same material as the first metal plate 3. As for the third metal plate 5, in consideration of ensuring heat dissipation and rigidity, one plate having a relatively large area in plan view is arranged as compared with the first metal plate 3 divided into a plurality of forms. It is desirable to have.

The plurality of first metal plates 3 and second metal plates 4 are joined to the upper surface of the first ceramic plate 1 or the lower surface of the second ceramic plate 2 via, for example, an Ag—Cu brazing material 10. This brazing material 10 contains at least one active metal material of, for example, titanium, hafnium and zirconium in order to be firmly bonded to the first ceramic plate 1 and the second ceramic plate 2 by being wetted. It may be. The brazing material 10 may include at least one metal material of indium and tin, for example. In addition, the thickness of this brazing material 10 should just be about 5-100 micrometers, for example.

  The third metal plate 5 is also joined to the first ceramic plate 1 and the second ceramic plate 2 by, for example, the same brazing material 10 as described above. That is, the upper surface of the third metal plate 5 and the lower surface of the first ceramic plate 1 are joined via the brazing material 10, and the lower surface of the third metal plate 5 and the upper surface of the second ceramic plate 2 are joined. 10 is joined through. For joining the first ceramic plate 1 and the second ceramic plate 2 to the first metal plate 3, the second metal plate 4 and the third metal plate 5 with the brazing material 10, for example, these members are matched to a predetermined positional relationship. At the same time, it may be temporarily fixed with a jig or the like and heated to a predetermined temperature in a furnace. The joining of each member may be performed in a lump, or may be performed sequentially in several steps.

  Here, an apparent thermal expansion coefficient of a portion (hereinafter referred to as a joined body) of the circuit board 20 sandwiching the upper and lower surfaces of the third metal plate 5 between the first ceramic plate 1 and the second ceramic plate 2 is expressed by the following equation. Can be expressed as

Apparent thermal expansion coefficient (α) = (α1 × E1 × t1 + α2 × E2 × t2 + α3 × E3 × t3) / (E1 × t1 + E2 × t2 + E3 × t3)
Where α is the thermal expansion coefficient, E is the Young's modulus, and t is the thickness. The numbers (1 to 3) following each symbol correspond to the first ceramic plate 1 (1), the second ceramic plate 2 (2), and the third metal plate 5 (3), respectively.

Assuming that the first ceramic plate 1 and the second ceramic plate 2 are both silicon nitride sintered bodies having a thickness of 0.32 mm (thermal expansion coefficient: 2.7 × 10 −6 / ° C., Young's modulus: 300 GPa), the third metal plate Assuming that 5 is copper having a thickness of 3 mm (thermal expansion coefficient: 16.8 × 10 −6 / ° C., Young's modulus: 120 GPa), the apparent thermal expansion coefficient of the joined body is 11.9 × 10 −6 / ° C. This is a value four times or more that of a single plate of a silicon nitride-based sintered body. Therefore, the difference between the thermal expansion coefficient of the joined body and the thermal expansion coefficient of the mold resin 8 is reduced, and the thermal stress is reduced.

  Note that a plating layer of nickel, gold, or the like may be applied to the exposed surfaces of the first metal plate 3 and the second metal plate 4. The plating layer is constituted by, for example, a nickel plating layer and a gold plating layer that are sequentially deposited from the exposed surfaces of the first metal plate 3 and the second metal plate 4, and the first metal plate 3 and the second metal plate 4. Each of the exposed surfaces is entirely covered. By applying this plating layer, the mounting of the electronic component 6 and the connection to an external electric circuit as described above can be made easier and stronger.

  Note that, as in the example illustrated in FIG. 2B, the side surface of the third metal plate 5 may be recessed in a concave curved surface shape. In this case, the stress applied to the first ceramic plate 1 and the second ceramic plate 2 at the side surface position of the third metal plate 5 is dispersed. Thereby, mechanical destruction of the first ceramic plate 1 and the second ceramic plate 2 is also effectively suppressed, and the reliability of the circuit board 20 is further improved.

  Further, as described above, the first ceramic plate 1 and the second ceramic are connected to the brazing material 10 joining the third metal plate 5 to the first ceramic plate 1 and the second ceramic plate 2 from the side of the third metal plate 5. When the fillet is formed over the plate 2, the stress applied to the first ceramic plate 1 and the second ceramic plate 2 is effectively dispersed by the fillet. Thereby, the reliability of the circuit board 20 and the electronic device 30 is further improved.

Further, when the fillet of the brazing material 10 is formed up to the outer edge portions of the first ceramic plate 1 and the second ceramic plate 2, the stress applied to the first ceramic plate 1 and the second ceramic plate 2 is changed to the respective outer edge portions. Will be distributed. That is, the stress is distributed over a wider range. Therefore, the reliability of the circuit board 20 and the electronic device 30 is further improved.

  Further, for the circuit board 20 of the embodiment, for example, as shown in FIGS. 1 and 2, the side surface of the third metal plate 5 is the side surface of the first metal plate 3 and the side surface of the second metal plate 4. It may be outside of both.

  When the side surface of the third metal plate 5 is located on the outer side with respect to both the side surface of the first metal plate 3 and the side surface of the second metal plate 4, the mechanical destruction as the circuit board 20 is prevented. The circuit board 20 that is more advantageous for improving the reliability can be provided.

  That is, the stress applied to the joint portion between the first ceramic plate 1 and the first metal plate 3 and the joint portion between the second ceramic plate 2 and the second metal plate 4 depends on the difference in thermal expansion coefficient of each material. There is a tendency that it becomes larger toward the outside of the center side of the substrate 20. On the other hand, the thicker side surface of the third metal plate 5 is located on the outer side than both the thinner side surfaces of the first metal plate 3 and the second metal plate 4. That is, both the first ceramic plate 1 and the second ceramic plate 2 are affected by the thermal expansion and contraction of the third metal plate 5 in the entire region where the first metal plate 3 and the second metal plate 4 are formed. As a result, the apparent thermal expansion coefficient increases. Therefore, the apparent thermal expansion coefficient of the first ceramic plate 1 and the second ceramic plate 2 to which the first metal plate 3 and the second metal plate 4 are joined is closer to the thermal expansion coefficient of the third metal plate 5. . Therefore, about the 1st ceramic plate 1 and the 2nd ceramic plate 2, the stress added to the junction part with the 1st metal plate 3 and the 2nd metal plate 4 also on the outer peripheral side is reduced effectively. Therefore, mechanical breakage in the first ceramic plate 1 and the second ceramic plate 2 due to this stress, and the joint portion between them and the first metal plate 3 or the second metal plate 4 is effectively suppressed. Thereby, for example, the temperature cycle reliability of the circuit board 20 becomes higher.

  Further, the circuit board 20 and the electronic device 30 in the example shown in FIGS. 1 and 2 are provided between the side surface of the third metal plate 5 and the side surface of the first ceramic plate 1 and the side surface of the second ceramic plate 2 in a cross-sectional view. Distances A1 and A2 are smaller than the thicknesses D1 and D2 of the first ceramic plate 1 and the second ceramic plate 2, respectively.

  In other words, the distance A1 between the side surface of the third metal plate 5 and the side surface of the first ceramic plate 1 and the third metal when the vertical cross section (vertical cross section) of the circuit board 20 and the electronic device 30 is viewed. The distance A2 between the side surface of the plate 5 and the side surface of the second ceramic plate 2, the thickness D1 of the first ceramic plate 1 and the thickness D2 of the second ceramic plate 2 are A1> D1, A1> D2, A2> D1 and Each relationship of A2> D2 is satisfied.

  In this case, the distances A1 and A2 between the side surface of the third metal plate 5 and the side surfaces of the first ceramic plate 1 and the second ceramic plate 2 are the same as described above. 5 is a distance between a virtual plane obtained by extending the side surfaces of 5 in the respective directions of the first ceramic plate 1 and the second ceramic plate 2 and each of the side surfaces of the first ceramic plate 1 and the second ceramic plate 2. .

  In the above configuration, the first ceramic plate 1 and the second ceramic plate 2 have a dimension of a portion outside the side surface of each third metal plate 5 (a lateral length away from the side surface of the third substrate 5). It is the structure smaller than each thickness. Also in this case, mechanical breakage at the first ceramic plate 1 and the second ceramic plate 2 and the joint portion between them and the first metal plate 3 or the second metal plate 4 is effectively suppressed.

  This is considered to be due to the following reasons. About the 1st ceramic plate 1 and the 2nd ceramic plate 2, the part to which the 3rd metal plate 5 was joined, and the part (the part to which the 3rd metal plate 5 is not joined) outside it are apparent heat. The expansion coefficients are different from each other. Therefore, stress tends to concentrate at a position corresponding to the side surface of the third metal plate 5 that is a boundary portion between them (hereinafter simply referred to as a boundary portion). On the other hand, in the case of the said structure, the dimension of the 1st ceramic plate 1 and the 2nd ceramic plate 2 outside the side surface of the 3rd metal plate 5 which is easy to generate | occur | produce distortion is smaller than each thickness. Therefore, in each of the first ceramic plate 1 and the second ceramic plate 2, the stress generated in the outer portion than the side surface of the third metal plate 5 is easily relaxed on the side surface that is the open end. Therefore, the stress is less likely to be concentrated on the boundary portion, and mechanical breakage of the first ceramic plate 1 and the second ceramic plate 2 at the boundary portion is effectively suppressed. Thereby, for example, the temperature cycle reliability of the circuit board 20 becomes higher.

As described above, the distance A1 between the side surface of the first ceramic plate 1 and the side surface of the third metal plate 5 and the distance A2 between the side surface of the second ceramic plate 2 and the side surface of the third metal plate 5 are as follows. When set in the range of 0.05 mm to 0.48 mm, the thicknesses D1 and D2 of the first ceramic plate 1 and the second ceramic plate 2 may be set according to the distance. That is, in such a case, the thicknesses D1 and D2 of the first ceramic plate 1 and the second ceramic plate 2 may be set to about 0.5 mm or more, respectively.

  3A is a cross-sectional view showing a first modification of the circuit board 20 and the electronic device 30 shown in FIG. 1, and FIG. 3B is a circuit board 20 and the electronic device 30 shown in FIG. It is sectional drawing which shows the 2nd modification of this. In FIG. 3, the same parts as those in FIG. In FIG. 3, the illustration of the mold resin 8 is omitted.

  In the example shown in FIG. 3A, the second ceramic plate 2 has a through-hole (no symbol) penetrating the second ceramic plate 2 in the thickness direction. A metal column 9 is disposed in the through hole. The metal column 9 has an upper end connected to the third metal plate 5 and a lower end connected to the second metal plate 4.

  The circuit board 20 and the electronic device 30 in the first modification are the same as the circuit board 20 and the electronic device 30 of the above-described embodiment except that the metal pillar 9 is included. In the following description, description of these similar matters is omitted.

  When the circuit board 20 and the electronic device 30 have the metal pillar 9 as described above, the third metal plate 5 and the second metal plate 4 are electrically connected. Further, the third metal plate 5 can be electrically connected to the external electric circuit via the second metal plate 4. Therefore, for example, the potential (ground potential or the like) of the third metal plate 5 can be effectively stabilized.

  In addition, the thermal conductivity between the third metal plate 5 and the second metal plate 4 can be improved. Therefore, the amount of heat dissipated from the second metal plate 4 through the third metal plate 5 or the like from the electronic component 6 can be further increased. Therefore, the heat dissipation to the outside can be further improved.

  The metal column 9 is a cylindrical member having a length that is approximately the same as the thickness of the second ceramic plate 2, for example. The metal pillar 9 is made of the same metal material as the first metal plate 3 and the second metal plate 4, for example. Such metal pillar 9 can be manufactured by the same metal processing as the first metal plate 3 and the second metal plate 4. Further, the joining of the upper end of the metal column 9 to the third metal plate 5 and the joining of the lower end to the second metal plate 4 can be performed by a brazing material (not shown) such as silver-copper brazing.

When the circuit board 20 and the electronic device 30 of the embodiment have the metal column 9, the side surface of the metal column 9 and the inner surface of the through-hole, as in the first modification shown in FIG. May be separated from each other. In this case, the generation of thermal stress due to the difference in thermal expansion coefficient between the metal column 9 and the second ceramic plate 2 is suppressed. Therefore, mechanical destruction of the second ceramic plate 2 due to the thermal stress is effectively suppressed. In this case, the distance between the side surface of the metal column 9 and the inner surface of the through hole may be about 100 μm. If the distance between the side surface of the metal column 9 and the inner surface of the through hole becomes too large, there is a possibility that miniaturization of the circuit board 20 and the electronic device 30 may be hindered. The effect of improving the thermal conductivity between the third metal plate 5 and the second metal plate 4 may be reduced.

  In the second modification shown in FIG. 3B, the thickness of the first ceramic plate 1 is larger than the thickness of the second ceramic plate 2. Further, the thickness of the first metal plate 3 is larger than the thickness of the second metal plate 4.

  The circuit board 20 and the electronic device 30 in the second modified example are the same as the circuit board 20 and the electronic device 30 of the above-described embodiment except for the above-described thickness elements. In the following description, description of these similar matters is omitted.

  When the thickness of the first ceramic plate 1 is larger than the thickness of the second ceramic plate 2, the electrical insulation between the upper and lower surfaces of the first ceramic plate 1 is improved, and the dielectric breakdown voltage of the first ceramic plate 1 is improved. To do. Therefore, a larger current can be passed through the first metal plate 3. Therefore, it becomes possible to send and receive a larger current between the electronic component 6 and the outside, and it is possible to provide the circuit board 20 and the electronic device 30 that are highly practical for IGBTs and the like.

  Further, since the thickness of the second ceramic plate 2 is relatively small, it is effective for reducing the height of the circuit board 20 and the electronic device 30. In addition, the thickness of the second ceramic plate 2 having a relatively low thermal conductivity is advantageous for improving the heat dissipation of the circuit board 20 and the electronic device 30.

  Further, when the thickness of the first metal plate 3 is larger than the thickness of the second metal plate 4, the electrical resistance of the first metal plate 3 is suppressed to be smaller than that of the second metal plate 4. Therefore, a large current can be passed through the first metal plate 3. Therefore, for example, in addition to the effect of the relatively large thickness of the first ceramic plate 1 described above, a larger current can be transmitted and received between the electronic component 6 and the outside, which is practical for IGBTs and the like. A high circuit board 20 and electronic device 30 can be provided.

  The difference in thickness between the first ceramic plate 1 and the second ceramic plate 2 in the configuration in which the thickness of the first ceramic plate 1 is larger than the thickness of the second ceramic plate 2 may be about 0.1 to 0.9 mm, for example. If the difference in thickness is within the above range, the circuit board 20 and the electronic device 30 that are effective for reducing the height and improving the heat dissipation and also effective for improving the characteristics such as the breakdown voltage are easier. Can be provided.

  In addition, by making the thickness of the first metal plate 3 larger than the thickness of the second metal plate 4, the warp of the circuit board 20 due to the plurality of first metal plates 3 and the second metal plate 4 becomes relatively small. The thickness of the plurality of first metal plates 3 may be appropriately set according to conditions such as electrical conductivity, thermal conductivity, and suppression of warpage as the circuit board 20.

In addition, this invention is not limited to the above embodiment, A various change is possible if it is in the range of the summary of this invention. For example, in the configuration having the metal pillar 9, the metal pillar 9 is the second
You may be located in the outer peripheral part of the ceramic board 2, and the some metal pillar (not shown) may be arrange | positioned. The plurality of metal pillars may have different diameters or may have different lengths.

  The metal pillar 9 may be formed through the first ceramic plate 1 so as to be connected to the ground potential portion of the first metal plate 3. For example, since the metal pillar 9 is connected to the mounting part of the electronic component 6, heat dissipation can be improved.

(Second Embodiment)
FIG. 4A is a plan view showing a circuit board 20 according to the second embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along line AA in FIG. 5 (a) is an enlarged cross-sectional view showing the main part of FIG. 4 (b) in an enlarged manner, and FIGS. 5 (b) and 5 (c) are enlarged cross-sectional views showing modifications of FIG. 5 (a), respectively. FIG. 4 and 5, the same reference numerals are given to the same parts as those in FIG. 1.

  4 and 5A, the third metal plate 5 has a recess 5a on the main surface (upper surface) on the first ceramic plate 1 side. A plurality of recesses 5 a are provided corresponding to each of the plurality of first metal plates 3. In addition, each of the recesses 5 a has an upper end of the side surface located outside the side surface of the first metal plate 3. That is, the upper surface of the third metal plate 5 has a recess 5a having a size including a portion overlapping the first metal plate 3 in a plan view.

  The presence of such a recess 5a increases the distance between the first metal plate 3 and the third metal plate 5 by the depth of the recess 5a. Therefore, the dielectric breakdown voltage between the 1st metal plate 3 and the 3rd metal plate 5 which function as a circuit conductor can be raised. In this case, since the recess 5a has a size including the first metal plate 3 in a plan view (see-through), the gap between the upper end of the side surface of the recess 5a (the opening edge portion of the recess 5a) and the side surface of the first metal plate 3 is large. The distance is also sufficiently large, and the breakdown voltage is effectively increased.

  Such a circuit board 20 and an electronic device 30 including the circuit board 20 can be used with higher reliability in applications that require a higher breakdown voltage, such as an electronic device for trains. For example, the recess 5a is formed in advance on one of the third metal plates 5 on the main surface (the surface that becomes the upper surface), and the third metal plate 5 is joined to the first ceramic plate 1 at a predetermined position. Can be arranged. The recess 5a can be formed, for example, on the upper surface of the third metal plate 5 by performing etching processing, machining by a grinding drill, etc., processing such as electric discharge machining alone or in combination. In this case, the mask shape at the time of etching may be also performed. Thereafter, the circuit board 20 can be manufactured by the same method as described above. Also, the electronic device 30 can be manufactured.

  The depth of the recess 5a is better as the distance between the first metal plate 3 and the third metal plate 5 is increased to increase the dielectric breakdown voltage. However, since the third metal plate 5 becomes thinner at the concave portion 5a when the concave portion 5a is deepened, the thermal conductivity of the third metal plate 5 is reduced, and the heat dissipation of the circuit board 20 and the electronic device 30 is thereby reduced. There is a possibility. Therefore, the depth of the recess 5a depends on the application of the electronic device 30 (required electrical characteristics, heat dissipation, etc.), the thickness of the third metal plate 5, the magnitude of the current transmitted through the first metal plate 3, and the recess 5a. It is set according to the workability and economics of the work for forming the.

In addition, when the inside of the recess 5a is in a reduced pressure state close to a vacuum, the improvement of the dielectric breakdown voltage is reduced. Therefore, for example, when the third metal plate 5 and the first ceramic plate 1 are joined in a vacuum furnace, as shown in FIG. The through-hole 1a may be formed over the outer surface such as the upper surface of one ceramic plate 1, and air may be introduced into the recess 5a. That is, the circuit board 20 and the electronic device having the through hole 1a as a through part (the reference number is not indicated as a through part) through which the first ceramic plate 1 penetrates from the recess 5a to the outer surface of the first ceramic plate 1 It may be 30.

  Further, as described above, the first metal plate 3 includes those that are connected to different electrodes of the electronic component 6, for example, those that are electrically connected to the respective electrodes for large current and control signals. Contains. That is, the first metal plate 3 includes one for a control signal and one for a large current that is a larger current than the control signal. In this case, the recess 5a may be located at a position corresponding to the first metal plate 3 for large current. Moreover, it may exist in the position corresponding only to the 1st metal plate 3 for large currents.

  When there is a concave portion 5a at a position corresponding only to the first metal plate 3 for large current, the first metal plate 3 while keeping the concave portion 5a as small as possible, that is, while ensuring higher heat conductivity of the third metal plate 5. And the breakdown voltage between the third metal plate 5 can be effectively improved.

  The details of the above effect are as follows. If the recess 5a corresponds to the first metal plate 3 functioning as the output signal transmission wiring and the power supply wiring (if the size includes the first metal plate 3 in a plan view), the recess 5a is insulated. The breakdown voltage can be increased. Moreover, since the die-bonding surface on which the electronic component 6 is mounted is set to the ground potential, the concave portion 5a may not be provided below the first metal plate 3 to which the electronic component 6 is bonded. The same applies to the first metal plate 3 to which a control signal is transmitted. Therefore, the number of recesses 5a in the third metal plate 5 (ratio of the area occupied by the recesses 5a in the top surface of the third metal plate 5 in a plan view) can be further reduced, and the heat generated from the electronic component 6 can be improved to a third level. It is transmitted to the metal plate 5. As a result, good heat dissipation of the circuit board 20 and the electronic device 30 including the circuit board 20 can be maintained.

  In addition, in order to suppress the fall of heat dissipation smaller, as shown in FIG.5 (b), the 1st metal plate 3 and the 3rd metal are inclined by inclining the side surface of the recessed part 5a toward an upper end from a lower end. The distance between the plate 5 can be further increased. The angle of inclination of the side surface of the recess 5a (the angle of inclination when the side surface is vertical) is, for example, about 45 degrees.

FIG. 5C shows an example in which the recess 11 is filled with the filler 11 in order to increase the dielectric breakdown voltage. Since the filler 11 has a higher breakdown voltage than air, the breakdown voltage between the first metal plate 3 and the third metal plate 5 can be improved. As the filler 11, epoxy resin (dielectric breakdown voltage: about 20 kV / mm), polyethylene resin (dielectric breakdown voltage: about 30 kV / mm), polyvinyl chloride resin (dielectric breakdown voltage: about 30 kV / mm), polyimide resin ( Dielectric breakdown voltage: 20
kV / mm), silicone resin (dielectric breakdown voltage: about 25 kV / mm), or the like can be used. That is, the resin material (filler 11) is disposed in the recess 5a.

  At least a part of the filler 11 is located outside the first metal plate 3 in a plan view. As a result, the filler 11 is interposed between the side surface of the first metal plate 3 and the side surface of the recess 5a located outside the side surface in a plan view, so that the dielectric breakdown voltage between the two is effectively reduced. And the above effects can be sufficiently obtained.

  By using such a resin filler 11, the dielectric breakdown voltage can be increased several times to 10 times that of air (dielectric breakdown voltage: about 3 kV / mm). For this reason, for example, when the same breakdown voltage is required, the depth of the recess 5a can be reduced, so that a reduction in heat dissipation can be further suppressed. The resin filler 11 can be filled into the recess 5a, for example, by being injected into the recess 5a from the through hole 1a.

FIG. 6 is a plan view showing a modification of the circuit board 20 shown in FIG. In FIG. 6, the same parts as those in FIG. 4 are denoted by the same reference numerals. As shown in FIG. 6, the plurality of recesses 5 a may be formed such that those adjacent to each other are connected to each other through a part of the penetrating portion. In this case, the resin filler 11 can be filled into the plurality of recesses 5a at a time.

  Further, when the filler 11 is not filled, the following effects can be obtained. If the through-hole 1a is close to the first metal plate 3, the creepage distance between the first metal plate 3 and the third metal plate 5 and the difference in distance are small, so that the effect of improving the breakdown voltage can be easily reduced. There is sex. On the other hand, in the example shown in FIG. 6, it is easy to form the through hole 1 a in the first ceramic plate 1 away from the first metal plate 3. For this reason, the above-described effects (such as the entry of air or filler 11 into the recess 5a) can be obtained, and the decrease in dielectric breakdown voltage due to the position of the through-hole 1a can be effectively suppressed. it can.

  When silicone resin is used as the filler 11, since the heat resistance of the silicone resin is relatively high and the Young's modulus is small, it is difficult for large stress to be applied to the third metal plate 5, so that the long-term reliability of the circuit board 20 is improved. Is advantageous.

  In the example shown in FIG. 5 (c), the filling material 11 is filled in the entire recess 5a. However, the filling range, in other words, the height of the filling material 11 depends on the desired dielectric breakdown voltage or the filling of the resin material. What is necessary is just to determine suitably according to conditions, such as workability | operativity of work. The filler 11 may be filled in all of the recesses 5a, but may be filled up partway to leave a space in the recesses 5a. When such a space exists, stress due to temperature change is easily relaxed in the space.

  FIG. 7A is a plan view showing another modified example of the circuit board 20 shown in FIG. 4, and FIG. 7B is a cross-sectional view taken along the line AA in FIG. 7, parts similar to those in FIG. 4 are denoted by the same reference numerals. The example shown in FIG. 7 is an example in which an opening 1 b penetrating from the recess 5 a to the upper surface of the first ceramic plate 1 is formed in the first ceramic plate 1. The opening 1b penetrates the first ceramic plate 1 in the thickness direction from the recess 5a. This example is also an example in which the first ceramic plate 1 has a penetrating portion penetrating from the concave portion 5 a to the outer surface of the first ceramic plate 1. The penetrating portion in this example is the opening 1b.

  Even in the case where such an opening 1b is formed, it becomes easy to fill the recess 5a with the resin material (which becomes the filler 11). When the electronic component 6 is mounted on the circuit board 20 and electrically connected, and then covered with the mold resin 8 such as silicone resin, the recess 5a is filled with the resin, and the filler 11 ( The manufacturing process of the electronic device 30 having the insulating material can be shortened.

  The filler 11 may be one in which fillers such as inorganic particles and additives such as a plasticizer are appropriately selected and added to the above resin material. With these additives, for example, the thermal expansion coefficient and Young's modulus of the filler 11 may be adjusted.

  FIG. 8A is a plan view showing still another modification of the circuit board 20 shown in FIG. 4, and FIG. 8B is a cross-sectional view taken along the line AA in FIG. 8A. In FIG. 8, the same parts as those in FIG. As shown in FIG. 8, an insulator 12 having a side surface outside the side surface of the first metal plate 3 may be disposed in the recess 5 a corresponding to the first metal plate 3. The insulator 12 is a block-like portion made of an insulating material other than the filler 11 made of resin or the like, and is disposed on the lower surface of the first ceramic plate 1 in advance, for example.

In this case, without forming the through-hole 1a in the first ceramic plate 1, the dielectric breakdown voltage between the first metal plate 3 and the third metal plate 5 functioning as a circuit conductor is used as an insulating material. Can be increased by 12. Therefore, it is possible to obtain a highly reliable circuit board 20 that can obtain a stable breakdown voltage without being affected by the humidity of the outside air. Therefore, for example, the circuit board 20 in which the electronic device 30 that can be effectively used for an application requiring a higher breakdown voltage such as a train can be easily manufactured can be obtained.

The insulator 12 may be alumina (dielectric breakdown voltage: about 15 kV / mm), silicon nitride (
In addition to ceramics with a dielectric breakdown voltage of about 12 kV / mm, sapphire that does not melt at the brazing temperature (dielectric breakdown voltage: about 48 kV / mm) or quartz glass (dielectric breakdown voltage: 30 kV / m)
m) or the like. These insulators 12 are formed, for example, in the same shape and size as the recess 5a or slightly smaller, and are disposed in the recess 5a.

  The insulator 12 can be produced by using the same material as that of the first ceramic plate 1 and the same method (ceramic green sheet firing or the like), for example. In this case, the first ceramic plate 1 having the insulator 12 can be manufactured by laminating the ceramic green sheet to be the insulator 12 on the ceramic green sheet to be the first ceramic plate 1 and simultaneously firing the ceramic green sheet.

  As shown in FIG. 8A, the recess 5 a and the insulator 12 may be formed so as to correspond to the plurality of first metal plates 3. In addition, the insulator 12 may be formed by previously forming a convex portion that fits in the concave portion 5a on the first ceramic plate 1 by cutting or stacking.

DESCRIPTION OF SYMBOLS 1 ... 1st ceramic plate 1a ... Through-hole 1b ... Opening 2 ... 2nd ceramic plate 3 ... 1st metal plate 4 ... 2nd metal plate 5 ... 3rd metal Plate 5a ... Recess 6 ... Electronic component 7 ... Bonding wire 8 ... Mold resin 9 ... Metal pillar
10 ... brazing material
11 ... filler
12 ... Insulator
20 ... Circuit board
30: Electronic device A1: Distance A2 between the side surface of the first ceramic plate 1 and the side surface of the third metal plate 5: The side surface of the second ceramic plate 2 and the side surface of the third metal plate 5 Distance D1 between the first ceramic plate 1 thickness D2 ... second ceramic plate 2 thickness

Claims (8)

A first ceramic plate having an upper surface including a region where the first metal plate is disposed;
A second ceramic plate having a lower surface including a region where the second metal plate is disposed;
A third metal plate thicker than any of the first metal plate and the second metal plate, which is disposed between the lower surface of the first ceramic plate and the upper surface of the second ceramic plate. ,
Each side surface of the first ceramic plate and the second ceramic plate is located outside the side surface of the third metal plate ,
The first metal plate includes a first metal plate for a control signal and a first metal plate for a large current that is a larger current than the control signal,
The circuit board characterized in that the upper surface of the third metal plate has a recess whose upper end of the side surface is located outside the side surface of the first metal plate 3 for large current in a plan view. . 2. The circuit board according to claim 1, wherein a side surface of the third metal plate is located outside a side surface of each of the first metal plate and the second metal plate. The distance between the side surface of each of the first ceramic plate and the second ceramic plate and the side surface of the third metal plate in the direction along the lower surface of the first ceramic plate or the upper surface of the second ceramic plate, The circuit board according to claim 1, wherein the circuit board is smaller than each thickness of the first ceramic plate and the second ceramic plate. The second ceramic plate has a through-hole penetrating the second ceramic plate in the thickness direction, and is disposed in the through-hole, and has an upper end connected to the third metal plate and the second The circuit board according to claim 1, further comprising a metal column having a lower end connected to the metal plate. The circuit board according to claim 1, wherein a thickness of the first ceramic plate is larger than a thickness of the second ceramic plate. 6. The circuit board according to claim 1, wherein the first ceramic plate has a penetrating portion penetrating from the concave portion to an outer surface of the first ceramic plate. . 6. The insulating material is disposed in the recess, and at least a part of the insulating material is located outside the first metal plate in a plan view . No
A circuit board according to any of the above. A circuit board according to any one of claims 1 to 7 ,
An electronic component mounted on the first metal plate;
An electronic apparatus comprising: a mold resin integrally covering the electronic component and a side surface of the second ceramic plate.

Images