JP2018006377A - Composite substrate, electronic device, and electronic module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite substrate and the like enabling easy manufacturing of an electronic module with high heat dissipation properties.SOLUTION: A composite substrate 10 includes a laminated body 9 composed of an insulating substrate 1 having an upper surface and a lower surface, a first metal plate 2 bonded to the upper surface of the insulating substrate 1, and a second metal plate 3 bonded to the lower surface of the insulating substrate 1 and thicker than the first metal plate 2. The laminated body 9 has a convex portion 9a curved upward at an intermediate portion between a central portion and the outer peripheral portion in plan view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a composite substrate including an insulating substrate and a metal plate bonded to the upper and lower surfaces of the insulating substrate, an electronic device, and a method for manufacturing the composite substrate.

Conventionally, a copper circuit formed in a circuit pattern on the upper surface of an insulating substrate as a composite substrate used in an electronic device on which electronic components such as IGBTs (insulated gate bipolar transistors) such as power modules or switching modules are mounted. A board is joined, and a copper heatsink for radiating heat generated from an electronic component mounted on a circuit board is joined to the lower surface. The circuit board and the heat sink are joined to the upper surface or the lower surface of the insulating substrate by a brazing material containing an active metal (see, for example, Patent Document 1).

  For example, an electronic component is mounted on a metal plate on the upper surface side of an insulating substrate to form an electronic device, and the composite substrate is mounted on an external member such as a mother board or a heat radiator included in various electronic devices.

  In recent years, it has become necessary for the composite substrate and the electronic device to cope with an increase in the amount of heat generated from the electronic components to be mounted. For this, it is conceivable to increase the heat dissipation to the outside by making the lower metal plate thicker than the upper metal plate.

JP-A-8-139420

  However, if the metal plate on the lower surface of the insulating substrate is made thicker than the metal plate on the upper surface, the influence of the thermal expansion of the relatively thick metal plate on the lower surface side of the insulating substrate becomes larger, and it is combined by heat during mounting as an electronic device. The entire substrate tends to warp upward at the outer periphery. In this case, since the outer peripheral portion of the composite substrate is less likely to adhere to an external member for heat dissipation or the like, heat conduction from the composite substrate (electronic device) to the external member is reduced, and heat dissipation is effectively improved. difficult.

  A composite substrate according to one aspect of the present invention includes an insulating substrate having an upper surface and a lower surface, a first metal plate bonded to the upper surface of the insulating substrate, and a lower surface of the insulating substrate. The laminate includes a second metal plate that is thicker than the plate, and the laminate has a convex portion that curves upward in an intermediate portion between the central portion and the outer peripheral portion in plan view. .

  An electronic device according to an aspect of the present invention includes the composite substrate having the above-described configuration and an electronic component mounted on the first metal plate.

  An electronic module according to one aspect of the present invention includes the electronic device having the above configuration and an external member to which the electronic device is bonded via a bonding material.

According to the composite substrate according to one aspect of the present invention, because of the above-described configuration, when heat is applied during mounting on the external member, stress is generated such that the peripheral portion of the convex portion is warped upward in the laminate. . The peripheral portions of the convex portions correspond to the outer peripheral portion and the central portion of the laminate (composite substrate) in plan view. Therefore, the flatness of the entire composite substrate can be increased by this thermal stress. Therefore, the adhesiveness with respect to an external member can be improved, for example, the composite substrate advantageous for the improvement of the heat dissipation as an electronic device can be provided.

  The central portion of the composite substrate in a plan view may be curved downward due to the stress generated in the peripheral portion of the convex portion. In this case, for example, the electronic component is mounted on the first metal plate in the central portion. If so, the distance from the electronic component to the external member can be kept small, so that the heat dissipation can be improved.

  According to the electronic device of one aspect of the present invention, since the composite substrate having the above-described configuration is included, it is easy to suppress the outer peripheral portion of the multilayer body from warping upward when mounted on an external member. It is possible to provide an electronic device that can easily improve adhesion to an external member and heat dissipation.

  According to the electronic module of one aspect of the present invention, since the electronic device including the composite substrate having the above-described configuration is mounted on the external member, the adhesion between the electronic device and the external member is high, and the heat dissipation is high. A high electronic module can be provided.

(A) is a top view which shows the composite substrate of embodiment of this invention, (b) is sectional drawing in the AA of (a), (c) is sectional drawing in the BB line. . It is sectional drawing which shows the electronic device of embodiment of this invention. It is a top view which shows the electronic module of embodiment of this invention. (A) is a top view which shows the modification of the composite substrate shown in FIG. 1, (b) is sectional drawing in the AA of (a), (c) is sectional drawing in the BB line. is there. It is sectional drawing which expands and shows typically the principal part of the composite substrate shown in FIG. It is sectional drawing which shows the modification of the electronic device shown in FIG. It is sectional drawing which shows the modification of the electronic module shown in FIG.

  Embodiments 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 composite substrate, the electronic device, and the electronic module are actually used. Moreover, in the following drawings, in order to make the shape and the like easier to understand, dimensions including the curvature may be emphasized more than actual.

(Composite substrate)
FIG. 1A is a plan view showing a composite substrate according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA in FIG. The composite substrate 10 includes a laminate 9 including an insulating substrate 1, a first metal plate 2 bonded to the upper surface of the insulating substrate 1, and a second metal plate 3 bonded to the lower surface of the insulating substrate 1. . The composite substrate 10 may include an auxiliary member (not shown) such as a plating film or a resin film in addition to the laminate 9.

  A laminate 9 composed of the insulating substrate 1, the first metal plate 2 and the second metal plate 3 is a part that basically constitutes the composite substrate 10. For example, a part of the upper surface of the first metal plate 2 is used as a mounting part for electronic components. Moreover, a part or all of the lower surface of the second metal plate 3 is used as a part for connection to an external member. The external member is an electronic circuit, a heat radiating member, or the like included in various devices such as an electronic device, a vehicle, or an industrial machine, and the composite substrate 10 is electrically and thermally connected thereto. Details of the external member will be described later.

The insulating substrate 1 functions as a base that holds the first metal plate 2 and the second metal plate 3 while ensuring electrical insulation. When the electronic component 4 is mounted on the upper surface of the first metal plate 2 to form an electronic device 20 to be described later, and when the lower surface of the second metal plate 3 is connected to an external member, an electronic module 30 to be described later is formed. In this case, heat generated in the electronic component 4 is conducted to the external member through the first metal plate 2, the insulating substrate 1, and the second metal plate 3.

  The insulating substrate 1 has a rectangular shape or a plate shape or the like in which a corner is curved (chamfered) in a plan view. The insulating substrate 1 is made of an electrically insulating material, for example, a material such as a silicon nitride sintered body, an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, or an aluminum nitride sintered body. Become. Among these materials, when importance is attached to thermal conductivity that affects heat dissipation, a silicon nitride sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, or the like is used. In consideration of mechanical strength, for example, a silicon nitride sintered body or a silicon carbide sintered body is used.

  When the insulating substrate 1 is made of a ceramic material having a relatively high mechanical strength such as a silicon nitride sintered body, the first metal plate 2 and the second metal plate 3 having a greater thickness (thickness) are used. However, the possibility of mechanical damage such as cracks occurring in the insulating substrate 1 can be reduced. Therefore, it is possible to realize the composite substrate 10 capable of flowing a larger current while reducing the size.

The thinner the insulating substrate 1, the better in terms of thermal conductivity. However, when considering mechanical strength, electrical insulation, etc., it should not be too thin. The thickness of the insulating substrate 1 is, for example, about 0.1 mm to 1 mm, and may be selected according to the size of the composite substrate 10 or the thermal conductivity or strength of the material used. The size of the insulating substrate 1 is, for example, about 5 to 50 mm in length and about 10 to 60 mm in width in plan view.

  If the insulating substrate 1 is made of, for example, a silicon nitride sintered body, it can be manufactured as follows. First, a slurry prepared by adding and mixing an appropriate organic binder, plasticizer and solvent to raw powders such as silicon nitride, aluminum oxide, magnesium oxide and yttrium oxide is formed into a sheet by a method such as a doctor blade method or a calender roll method. Molding to form a ceramic green sheet. Next, the ceramic green sheet is subjected to an appropriate punching process or the like to obtain a predetermined shape, and a plurality of sheets are laminated and processed into a molded body as necessary. Thereafter, the compact is fired at a temperature of 1600 to 2000 ° C. in a non-oxidizing atmosphere such as a nitrogen atmosphere. The insulating substrate 1 can be manufactured by the above process.

The first metal plate 2 is bonded to the upper surface of the insulating substrate 1, and the second metal plate 3 is bonded to the lower surface of the insulating substrate 1. The first metal plate 2 and the second metal plate 3 are made of, for example, a metal material such as copper or an alloy containing copper as a main component. In the composite substrate 10 and the electronic device 20, the thickness of the second metal plate 3 is set to be twice or more the thickness of the first metal plate 2. If a specific example is given, the thickness of the 1st metal plate 2 will be set to about 0.4-0.6 mm, and the thickness of the 2nd metal plate 3 will be set to about 0.8-1.2 mm. In this case, the thickness of the second metal plate 3 may be set to a thickness exceeding 1.2 mm in consideration of improvement in heat dissipation, suppression of deformation of the laminated body 9 due to thermal stress, economy, and the like. .

  The first metal plate 2 and the second metal plate 3 are attached to the insulating substrate 1 after a copper original plate (not shown) is formed by a predetermined metal processing such as die punching or etching, for example. Alternatively, the first metal plate 2 or the second metal 3 can be formed by bonding an original copper plate to the upper surface or the lower surface of the insulating substrate 1 and then performing an etching process or the like on the original plate. The first metal plate 2 and the second metal plate 3 are joined to the insulating substrate 1 by a joining method such as brazing. The brazing material is, for example, silver brazing, and may be obtained by adding an active metal material such as titanium to silver brazing.

  In addition, the laminate 9 included in the composite substrate 10 has a convex portion 9a that is curved upward in an intermediate portion between the central portion and the outer peripheral portion in plan view. The central portion of the laminate 9 in plan view is, for example, a portion surrounded by an inner virtual line (two-dot chain line) in FIG. In the case of the rectangular laminated body 9, the center and the vicinity thereof are the central part. The outer peripheral part in planar view of the laminated body 9 is a part outside the outer virtual line (two-dot chain line) in FIG. 1A, for example. If it is the rectangular laminated body 9, it is a square frame-shaped part along the outer periphery.

  In addition, the outer periphery of the laminated body 9 is an outer edge of the member located on the outermost side when viewed from above, and corresponds to the outer periphery of the insulating substrate 1 in this example. That is, the central portion and the outer peripheral portion of the laminate 9 in plan view can be regarded as corresponding to the central portion and the outer peripheral portion of the insulating substrate 1 in plan view, respectively.

  According to the composite substrate 10 of such an embodiment, because of the above configuration, when heat is applied during mounting on an external member, stress that causes the peripheral portion of the convex portion 9a to warp upward in the laminate 9. Occurs. The peripheral portion of the convex portion 9a corresponds to the outer peripheral portion and the central portion of the laminate 9 (composite substrate 10) in plan view. Therefore, the flatness of the entire composite substrate 10 can be increased by this thermal stress. Therefore, it is possible to improve the adhesion to the external member, and for example, it is possible to provide the composite substrate 10 that is advantageous for improving the heat dissipation as the electronic device 20.

  In other words, by bending the laminated body 9 in the above-described form (in an M shape in a longitudinal cross-sectional view), a deformation that causes the entire laminated body 9 to be flattened by the heat during mounting is generated. be able to. The deformation due to the stress is opposite to the deformation that causes the outer peripheral portion of the composite substrate (not shown) in the prior art to warp upward. Therefore, the flatness of the composite substrate 10 is improved in the electronic device (electronic module) after mounting. This can also be regarded as a result of the protrusions 9a being stretched in the lateral direction due to thermal stress during mounting.

  In order to obtain the above effects, the height of the convex portion 9a may be set to about 20 μm to 80 μm. The height of the convex portion 9a is, for example, the distance from the virtual level surface L0 to the upper surface of the convex portion 9a in the longitudinal sectional view as shown in FIG. 1B, and particularly the height H at the maximal portion. It is. When there are a plurality of convex portions 9a (a plurality of maximal portions are present), the height of each convex portion 9a is individually defined, and the height of these convex portions 9a May be in the above range.

  The virtual level surface may be set arbitrarily, but the level surface L0 in the above example is the position where the upper surface of the laminate 9, that is, the position of the upper surface of the first metal plate 2 is the lowest. It is set. In the case of this example, the center portion of the upper surface of the rectangular first metal plate 2 is the level surface L0.

(Production method of composite substrate)
The composite substrate 10 of the embodiment can be manufactured by a manufacturing method including the following processes, for example. However, the manufacturing method of the composite substrate 10 is not limited to this example, and can be appropriately changed according to the type or size of the material to be used, productivity, economy, and the like.

First, the insulating substrate 1 is produced by the method as described above. The insulating substrate 1 is set in accordance with the outer dimensions, predetermined characteristics, economy, etc. of the composite substrate 10 to be manufactured, and the material to be used is selected. For example, the insulating substrate 1 having a rectangular shape (square shape or rectangular shape) having a thickness of about 0.1 mm to 1 mm and a side dimension of about 5 to 60 mm in plan view is manufactured by a method of firing a ceramic green sheet. To do.

Next, the first metal plate 2 and the second metal plate 3 are produced. First metal plate 2 and second metal plate 3
Can be produced by subjecting a copper base plate such as oxygen-free copper to predetermined metal processing such as cutting, rolling and etching. The first metal plate 2 and the second metal plate 3 are produced, for example, as flat plates having outer dimensions slightly smaller than those of the insulating substrate 1 in plan view. At this time, the dimension at the time of metal processing is adjusted so that the thickness of the second metal plate 3 is about twice the thickness of the first metal plate 2. The size (dimension) in plan view of the first metal plate 2 and the second metal plate 3 depends on the size in plan view of the first metal plate 2 and the second metal plate 3 in the composite substrate 10 to be manufactured. It may be adjusted appropriately. For example, at least one of the first metal plate 2 and the second metal plate 3 to be manufactured may be larger than the insulating substrate 1 in plan view.

  Next, the first metal plate 2 and the third metal plate 3 are joined to the insulating substrate 1. This joining can be performed by, for example, a joining method through a brazing material (not shown) such as silver brazing. The silver solder is, for example, a silver-copper solder such as JIS standard BAg-8.

  The brazing material may further contain at least one metal material of molybdenum, titanium and zirconium, hafnium and niobium as an additive as an active metal for bonding. In consideration of the effectiveness as an active metal, the workability of brazing, and the economical efficiency (cost) of these metal materials, molybdenum, titanium, and zirconium are suitable as the active metal for the above-mentioned use.

  When heating the laminated body 9 (unjoined temporary laminated body) obtained by laminating the second metal plate 3, the insulating substrate 1, and the first metal plate 2 in order from the bottom, the temporary laminated body has a predetermined shape (the longitudinal section described above). Apply a load that can be deformed into an M shape. For example, when the temporary laminate is turned upside down and heated, a load is applied downward to the intermediate portion. As a specific example, a jig having an appropriate mass is placed on the second metal plate 3 (on the lower surface before being turned over) and heated. Due to this load, deformation occurs in the intermediate portion of the temporary laminate during heating, and the composite substrate 10 including the laminate 9 having a predetermined shape can be manufactured. That is, during heating, the intermediate portion becomes convex downward due to the force due to the mass of the jig, and the downward direction at this time is the upward direction in the example of FIG. 1, so the intermediate portion as shown in FIG. It can be set as the laminated body 9 curving convexly upward.

(Electronic device)
FIG. 2 is a cross-sectional view showing the electronic device 20 according to the embodiment of the present invention. The electronic device 20 of the embodiment is basically configured by the composite substrate 10 having the above configuration and the electronic component 4 mounted on the first metal plate 2. In FIG. 2, the same parts as those in FIG. In FIG. 2, the electronic component 4 and the composite substrate 10 are shown separately, and the direction in which the electronic component 4 is mounted is indicated by an arrow. The direction in which the electronic device 20 is mounted on the external member 5 is indicated by an arrow. In each of the following drawings, as in FIG. 2, the constituent members may be shown separately, and the mounting direction may be indicated by an arrow.

The electronic component 4 is mounted, for example, at the center of the upper surface of the first metal plate 2 that is rectangular in plan view. The electronic component 4 is, for example, a semiconductor element such as a transistor, an LSI (Large Scale Integrated circuit) for a CPU (Central Processing Unit), an IGBT (Insulated Gate Bipolar Transistor), or a MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor). is there. The electronic component 4 is not limited to a semiconductor element, and may be appropriately selected from various electronic components including a sensor element such as a temperature sensor element and a passive component such as a capacitive element, or may be plural. Different types of electronic components (not shown) may be mounted.

The electronic component 4 is bonded to the upper surface of the first metal plate 2 by a bonding method such as bonding via a bonding material (not shown) for components. The bonding material for parts is made of, for example, metal or conductive resin. The bonding material for components is, for example, solder (tin-lead eutectic solder or the like), gold-tin (Au-Sn) alloy, tin-silver-copper (Sn-Ag-Cu) alloy, or the like.

A plating film (not shown) may be formed on the surface of the first metal plate 2 by a plating method. According to this configuration, since the wettability of the bonding material for components is improved, the bonding strength of the electronic component 4 to the upper surface of the first metal plate 2 can be improved. As the plating film, a metal having high conductivity and corrosion resistance may be used. For example, a plating film of nickel, cobalt, silver, copper, gold, or the like is used. The plating film may be an alloy material mainly composed of these metal materials, or may be one in which a plurality of layers are sequentially deposited. The thickness of the plating film may be, for example, 0.1 to 10 μm.

  The semiconductor element mounted as the electronic component 4 is electrically connected to an external electric circuit (not shown) by a conductive connecting material (not shown) such as a bonding wire. The external electric circuit is included in the external member 5, and various signals or predetermined potentials such as ground are exchanged between the semiconductor element and the external electric circuit.

  For example, when the external member 5 is a circuit board (motherboard or the like) of a device having an electronic control mechanism such as a computer or an automobile, information serving as a basis for calculation is transmitted from the external member 5 to the electronic component 4 and from the electronic component 4 to the outside. An operation result or stored information is transmitted to the electric circuit.

  Further, the heat generated by the operation of the electronic component 4 is conducted to the second metal plate 3 as described above, and is conducted from the second metal plate 3 to the external member 5. In this case, the circuit board may promote heat transfer and heat dissipation to the outside. Moreover, the external member 5 for heat dissipation other than an external electric circuit may be joined to the 2nd metal plate 3, and heat dissipation to the exterior may be accelerated | stimulated.

(Electronic module)
FIG. 3 is a plan view showing the electronic module according to the embodiment of the present invention. The electronic module 30 of the embodiment is basically configured by the electronic device 20 having the above configuration and the external member 5 to which the electronic device 20 is bonded via the bonding material 6. In FIG. 3, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  The bonding material 6 is a low melting point brazing material such as solder. Examples of the solder include tin-lead solder (eutectic solder, etc.), tin-copper, tin-silver-copper, tin-silver-bismuth, and the like. For example, the electronic device 20 and the external member 5 can be joined to each other by aligning the electronic device 20 and the external member 5 via a solder paste and then heating and melting the solder paste.

  For example, as described above, the external member 5 is various members constituting an electronic circuit portion in a computer, various control devices for vehicles, industrial machines, communication devices, and the like. The external member 5 may have a function of an external electric circuit having an electronic circuit, or may have a function of heat dissipation. In the example shown in FIG. 3, an example is shown in which the electronic device 20 is bonded and mounted on a mother board (external member 5) included in an electronic device such as a computer.

  According to the electronic module 30 of such an embodiment, as described above, due to heat at the time of mounting, a thermal stress is generated such that the laminate 9 extends at the convex portion 9a. This deformation acts in the direction opposite to the direction in which the outer peripheral portion of the laminate 9 becomes flat in the upward direction. That is, a stress is generated that flattens the entire laminated body 9 that was bent before mounting.

For example, as in the example shown in FIG. 3, the central portion of the laminate 9 (composite substrate 10) in a plan view may be curved downward due to the stress generated in the peripheral portion of the convex portion 9a. However, even in this case, for example, if the electronic component 4 is mounted on the first metal plate 2 in the central portion, the distance from the electronic component 4 to the external member 5 can be kept small, so that the heat dissipation is improved. Is possible.

  When the center part of the laminated body 9 (composite substrate 10) curves downward, the height of the curved part (distance in side view from the part other than the curved part of the lower surface of the second metal plate 3 to the lower end of the curved part) ) May be in the range of, for example, about 20 to 80 μm. Within this range, the effect of reducing the distance between the electronic component 4 and the external member 5 in the curved portion can be effectively obtained, and the second metal plate 3 (composite substrate 10) in the intermediate portion and the outer peripheral portion can be obtained. ) And the external member 5 can be kept relatively small to ensure high heat transfer.

(Modified example of composite substrate)
4A is a plan view showing a modification of the composite substrate 10 shown in FIG. 1, FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A, and FIG. These are sectional drawings in the BB line of Drawing 4 (a). FIG. 5 is a cross-sectional view schematically showing an enlarged main part of the composite substrate 10 shown in FIG. 4 and 5, the same reference numerals are given to the same parts as those in FIGS. 1 to 3. The electronic device 20 and the electronic module 30 may include the composite substrate 10 of this modification.

  In the example shown in FIG. 4, the stacked body 9 has a rectangular shape in plan view, and the upper end of the convex portion 9 a is located above the other portion in a portion near the corner of the stacked body 9. In other words, the height of the convex portion 9a is higher in the portion near the corner portion of the stacked body 9 than in other portions. In the example shown in FIG. 4A, the heights of the convex portions 9a are shown as L1, L2, and L3 in order from the portion having the closest distance from the level surface L0. For example, if the size of the insulating substrate 1 in plan view is about 50 to 60 mm as described above, L1 is a region whose distance from the L0 center point is about 6 to 58 mm, and L2 is L0. Is a region where the distance from L0 is about 15 to 54 mm, and L3 is a region where the distance from L0 is about 23 to 49 mm.

  When the height of the convex portion 9a is set to about 20 to 80 μm as described above, the height of the highest portion (L3) of the upper surface of the convex portion 9a near the corner is about 40 to 80 μm. I just need it. In this case, the height of the highest portion (L2) of the upper surface of the convex portion 9a may be about 20 to 60 μm near the side portion that is a portion other than the corner portion. In this case, the height of the convex portion 9a in the region L1 is less than about 40 μm, and is 1 μm or more.

  Note that the height of the convex portion 9a and the distribution of the height are measured by observing a cross section of the laminate 9 cut in the thickness direction and measuring the height of the convex portion 9a with a metal microscope or the like. Can do. Moreover, the height of the convex part 9a can also be measured using measuring instruments, such as a shadow moire method, and can be specifically measured with various commercially available measuring instruments.

  In the example shown in FIG. 4, for example, as shown in FIG. 5, the slope of the side surface of the convex portion 9 a in the portion near the corner of the laminate 9 is larger on the outer peripheral side of the laminate 9 than on the center side. It may be. FIG. 5 is a cross-sectional view schematically showing an enlarged main part of the composite substrate 10 shown in FIG. 5, parts similar to those in FIG. 4 are denoted by the same reference numerals.

  The gradient of the side surface of the convex portion 9a corresponds to the angle θ of the angle formed between the side surface of the convex portion 9a and the virtual horizontal plane L in a longitudinal sectional view as in the example illustrated in FIG. When the side surface of the convex portion 9a is a curved surface and is a curved line in a longitudinal sectional view, the angle θ between the tangent line S and the horizontal plane L with respect to the curved line has the above gradient. The virtual horizontal plane L is a plane parallel to the virtual level surface L0 in the above example, for example.

  When the angle between the side surface of the convex portion 9a and the horizontal plane (side surface inclination) is not constant in the length direction of the side surface, the average value of the angles can be regarded as the gradient. Further, this average value can be substituted by an angle formed by a virtual straight line connecting a maximal portion (vertex or the like) of the convex portion 9a and the lower end of the side surface of the convex portion 9a and a virtual horizontal plane.

  In this case, it is possible to increase the room for deformation (deformation margin) in the upward direction on the outer peripheral side surface of the stacked body 9 in the convex portion 9a. That is, it is possible to further increase the room for deformation until reaching the warpage of the portion of the laminate 9 on the outer peripheral side where it is desired to more effectively suppress the upward warping. Therefore, the upward warpage of the outer peripheral portion of the multilayer body 9 in the electronic module 30 can be effectively suppressed.

  Therefore, an electronic module 30 that is advantageous in improving the adhesion between the electronic device 20 and the external member 5 and heat dissipation can be obtained. Further, the electronic device 20 and the composite substrate 10 in which the electronic module 30 can be easily manufactured can be obtained.

(Modification of electronic device)
FIG. 6 is a cross-sectional view showing a modification of the electronic device 20 shown in FIG. In FIG. 6, the same parts as those in FIGS.

  In the example shown in FIG. 6, the composite substrate 10 is turned upside down and used to form the electronic device 20. As described above, the upper and lower sides when the composite substrate 10 is actually used are not limited to the above-described embodiment and its modified examples (examples shown in FIGS. 1 to 6), but as in the example of FIG. The second metal plate 3 may be used in an upward direction, and the electronic component 4 may be mounted on the second metal plate 3. The first metal plate 2 may be mounted to face the external member 5.

  Even in the case of the electronic device 20 of the form shown in FIG. 6, the composite substrate 10 of the embodiment is included as in the case of the electronic device 20 shown in FIG. Deformation occurs such that the substrate 10 becomes flat. Therefore, the electronic device 20 having high adhesion to the external member 5 can be obtained.

  Further, since the electronic component 4 is mounted on the second metal plate 3 having a relatively large thickness, heat conduction from the electronic component 4 to the composite substrate 10 can be effectively increased. Further, this heat can be effectively dissipated to the outside from the side surface of the second metal plate 3 having a relatively large area. Further, since the total thickness of the first metal plate 2 and the second metal plate 3 is approximately the same as that of the electronic device 20 of the above embodiment, heat conduction from the electronic component 4 to the external member 5 is also effectively generated. . Therefore, it is possible to provide the electronic device 20 with high heat dissipation from the electronic component 4.

(Modification of electronic module)
FIG. 7 is a cross-sectional view showing a modification of the electronic module 30 shown in FIG. 7, parts similar to those in FIGS. 1 to 3 are denoted by the same reference numerals.

  In the example shown in FIG. 7, the composite substrate 10 is mounted on the external member 5 in the vertical direction. As described above, the direction including the top and bottom when the composite substrate 10 is actually used is not limited to the above-described embodiment and its modification.

  In the example shown in FIG. 7, a plurality of electronic components 4 are mounted on the composite substrate 10. As described above, the number of electronic components 4 is not limited to one, and a plurality of electronic components 4 may be mounted. When a plurality of electronic components 4 are mounted, high functionality as the electronic module 30 is effectively performed.

  Even in the case of the electronic device 20 and the electronic module 30 of the form shown in FIG. 7, the composite substrate 10 of the embodiment is included as in the case of the electronic device 20 shown in FIG. 2 and the electronic module 30 shown in FIG. Thus, the electronic module 30 can be effectively flattened during mounting, and the electronic device 30 having high adhesion between the electronic device 20 and the external member 5 can be obtained.

  The plurality of electronic components 4 to be mounted may be of the same type (for example, a plurality of semiconductor elements for storage) or different from each other (for example, a semiconductor integrated circuit element, a sensor element, and a passive component). Or a combination thereof.

  The external member 5 on which the electronic device 20 is mounted is not limited to the mother board or the like in the above-described example, and may be the heat radiating member 5 (5A) including the heat radiating fins. Thereby, the electronic module 30 with improved heat dissipation can be obtained.

  The external member 5 may be a bus bar 5 (5B) or the like. The bus bar 5 (5B) is electrically connected to a power source portion such as a battery in various vehicles on which an electric motor is mounted, for example. Thereby, the management and control of the power source of the vehicle having a conductive mechanism such as a hybrid vehicle or an electric vehicle can be effectively performed.

1..Insulating substrate 2..First metal plate 3..Second metal plate 4..Electronic component 5..External member 5 (5A) .. External member (heat dissipating member)
5 (5B) ・ ・ External material (Bus bar)
6 ・ ・ Joint material 9 ・ ・ Laminate
10. ・ Composite substrate
20 ・ ・ Electronic equipment
30 ・ ・ Electronic module L0 ・ ・ Virtual level

Claims (5)

An insulating substrate having an upper surface and a lower surface;
A first metal plate bonded to the upper surface of the insulating substrate;
It is bonded to the lower surface of the insulating substrate, and includes a laminate composed of a second metal plate thicker than the first metal plate,
A composite substrate in which the laminate has a convex portion that curves upward in an intermediate portion between a central portion and an outer peripheral portion in plan view. 2. The composite substrate according to claim 1, wherein the stacked body is rectangular in a plan view, and an upper end of the convex portion is positioned above the other portion in a portion close to a corner of the stacked body. The composite substrate according to claim 2, wherein a slope of a side surface of the convex portion in a portion near the corner portion of the stacked body is larger on the outer peripheral side of the stacked body than on the central portion side. The composite substrate according to any one of claims 1 to 3,
An electronic device comprising: an electronic component mounted on the first metal plate. An electronic device according to claim 4,
An electronic module comprising: an external member to which the electronic device is bonded via a bonding material.

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