Substrate, electronic device, electronic module, and module device

Abstract

The present invention improves heat conductivity. The present invention comprises: a base body having a first surface, a second surface located on the opposite side of the first surface, at least one first recess that opens in the first surface, and at least one second recess that opens in the second surface; a first metal member located inside the first recess; and a second metal member located inside the second recess, wherein the heat conductivity of the first metal member and the heat conductivity of the second metal member are higher than the heat conductivity of the base body.

Description

Substrate, electronic device, electronic module and module device

[0001] The present disclosure relates to a substrate on which an electronic element is mounted.

[0002] As disclosed in Patent Documents 1 and 2, substrates on which electronic elements are mounted are known that have improved thermal conductivity in order to quickly dissipate heat generated by the electronic elements.

[0003] International Publication No. 2018-117232 International Publication No. 2011-059070

[0004] A substrate according to one aspect of the present disclosure comprises a base body including a first surface, a second surface located opposite the first surface, at least one first recess opening into the first surface, and at least one second recess having an opening in the second surface, a first metal member located inside the first recess, and a second metal member located inside the second recess, wherein the thermal conductivity of the first metal member and the thermal conductivity of the second metal member are higher than the thermal conductivity of the base body.

[0005] 1. A perspective view of a module device according to a first embodiment of the present disclosure. A top view of the module device. A cross-sectional view taken along line III-III in FIG. 2. A top view of a substrate according to a first embodiment of the present disclosure. A view of the substrate and electronic elements according to the first embodiment of the present disclosure, as viewed from the Y-axis direction. A top view of a substrate according to a second embodiment of the present disclosure. A view of the substrate and electronic elements according to the second embodiment of the present disclosure, as viewed from the Y-axis direction. A top view of a substrate according to a third embodiment of the present disclosure. A view of the substrate and electronic elements according to the third embodiment of the present disclosure, as viewed from the Y-axis direction. A top view of a substrate according to a fourth embodiment of the present disclosure. A cross-sectional view taken along line XI-XI in FIG. 10. A cross-sectional view taken along line XII-XII in FIG. 10. A top view of a substrate according to a fifth embodiment of the present disclosure. A view of the substrate and electronic elements according to the fifth embodiment of the present disclosure, as viewed from the Y-axis direction.

[0006] There is a demand for substrates on which components such as electronic elements are mounted that have improved thermal conductivity.

[0007] According to one aspect of the present disclosure, thermal conductivity can be improved.

[0008] [Embodiment 1] An embodiment of the present disclosure will be described in detail below. FIG. 1 is a perspective view of a module device 1 according to this embodiment. FIG. 2 is a top view of the module device 1. For ease of explanation, the top surface of a case 11, which will be described later, is omitted from FIG. 2. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. In the following description, the X-axis direction in FIG. 1 will be referred to as the second direction (left-right direction) of the module device 1, the Y-axis direction as the third direction (front-rear direction) of the module device 1, and the Z-axis direction as the first direction (up-down direction) of the module device 1. In addition, in FIG. 1, the +X-axis direction will be referred to as the rightward direction, the −X-axis direction as the leftward direction, the +Y-axis direction as the rearward direction, the −Y-axis direction as the forward direction, the +Z-axis direction as the upward direction, and the −Z-axis direction as the downward direction.

[0009] As shown in Figures 1 to 3, the module device 1 includes an electronic module 10 and a housing 2 in which the electronic module 10 is mounted. The housing 2 may be configured, for example, with a cooling plate, thereby cooling the electronic module 10. The module device 1 may include one electronic module, or two or more electronic modules. The electronic module 10 may be mounted on a module substrate (not shown) instead of the housing 2.

[0010] As shown in FIGS. 2 and 3, the electronic module 10 includes a case 11, a fixing member 12, and an electronic device 20.

[0011] The case 11 has an accommodation space 11a in the center in the second direction (left-right direction), and accommodates the electronic device 20 inside the accommodation space 11a. The case 11 is fixed to the housing 2 by a fixing member 12. The fixing member 12 may be, for example, a screw. The material of the case 11 may be metal.

[0012] As shown in FIG. 3, the electronic device 20 includes, from top to bottom, an electronic element 21, a substrate 30A, a metal plate 22, and a heat sink 23.

[0013] The electronic element 21 in this embodiment is configured by a laser diode or the like capable of emitting a laser, and the electronic device 20 irradiates the laser emitted from the electronic element 21 toward the outside.

[0014] In the electronic device 20, heat generated when the electronic element 21 is operated is conducted to the heat sink 23 via the substrate 30A and the metal plate 22, and is dissipated by the heat sink 23. Therefore, the substrate 30A is required to have high heat dissipation properties. Furthermore, a portion of the heat conducted to the heat sink 23 is conducted to the housing 2, which is composed of a cooling plate, via the case 11, and is dissipated in the housing 2.

[0015] The substrate 30A is an electronic element mounting substrate for mounting an electronic element 21. The substrate 30A may also be used to mount heat-generating components other than electronic elements. FIG. 4 is a top view of the substrate 30A. For ease of explanation, in FIG. 4, an electronic element mounting portion 41a and a recess 50, which will be described later, are indicated by dotted lines, and the recess 50 formed on the second surface 42 is illustrated by hatching. FIG. 5 is a view of the substrate 30A and the electronic element 21 as viewed from a third direction (front-rear direction). In FIG. 5, the recess 50 is indicated by a dotted line.

[0016] As shown in FIGS. 4 and 5, the substrate 30A includes a base body 40A, a metal member 51, a first conductive film layer 31, and a second conductive film layer 32.

[0017] The base 40A may be composed of a single layer or multiple layers. In this embodiment, the base 40A is a single insulating layer, as shown in FIG. 5 . The base 40A has a first surface 41 on which the electronic element 21 is mounted, a second surface 42 located opposite the first surface, and a recess 50. In the following description, the recess 50 having an opening in the first surface 41 may be referred to as the first recess 50A, and the recess 50 having an opening in the second surface 42 may be referred to as the second recess 50B. The first surface 41 and the second surface 42 are opposed to each other. As shown in FIG. 4 , the first surface 41 has an electronic element mounting portion 41a at the center in the second direction on which the electronic element 21 is mounted.

[0018] The shape of the base 40A when viewed from above is not particularly limited, and may be, for example, rectangular, circular, etc. The base 40A in this embodiment has a rectangular shape when viewed from above. In this specification, the terms "flat" or "plane" do not require that the base 40A be strictly flat or plane.

[0019] The base 40A may be insulating. In this case, the material of the base 40A may be ceramic, such as an aluminum nitride sintered body, an aluminum oxide sintered body (alumina ceramics), a silicon nitride sintered body, a mullite sintered body, or a glass ceramic sintered body. When the material of the base 40A is an aluminum nitride sintered body, the base 40A contains aluminum nitride as a main component. In this case, when the mass of the base 40A is taken as 100 mass%, the base 40A contains 80 mass% or more of aluminum nitride. The base 40A may also contain 95 mass% or more of aluminum nitride. This makes it easier to achieve a thermal conductivity of 170 W / mK or more, thereby improving the heat dissipation properties of the base 40A.

[0020] The base 40A has at least one recess 50 on each of the first surface 41 and the second surface 42. In the present embodiment, the base 40A has a plurality of recesses 50 on each of the first surface 41 and the second surface 42.

[0021] The recess 50 may have a cavity structure. The opening of the recess 50 may have a circular shape when the substrate 30A is viewed from above in the first direction. The recess 50 has a bottom.

[0022] When the base 40A has a plurality of recesses 50 on each of the first surface 41 and the second surface 42, the arrangement of the plurality of recesses 50 is not particularly limited, but may be, for example, as shown in Fig. 4, arranged such that four adjacent recesses 50 are located at the vertices of a rectangle on each of the first surface 41 and the second surface 42. In other words, the plurality of recesses 50 may be arranged in a lattice pattern on each of the first surface 41 and the second surface 42. This allows the plurality of recesses 50 to be evenly arranged when the substrate 30A is viewed in plan, making it less likely that variations will occur in the heat dissipation properties of the substrate 30A.

[0023] As shown in FIG. 5 , the first recess 50A provided in the first surface 41 may be tapered with increasing distance from the first surface 41 in a cross section cut along a plane parallel to a first direction (i.e., the up-down direction) perpendicular to the first surface 41 and the second surface 42. In other words, the width of the first recess 50A in the second direction may be reduced with increasing distance from the first surface 41 on which the first recess 50A is provided in a cross section cut along a plane parallel to the first direction. As shown in FIG. 5 , the shape of the first recess 50A may be a curved shape that is convex from the first surface 41 to the second surface 42 in a cross section cut along the first direction. For example, the shape of the first recess 50A in a cross section cut along a plane parallel to the first direction may be an elliptical hemisphere.

[0024] As shown in Fig. 5 , the second recess 50B provided in the second surface 42 may become thinner as the distance from the second surface 42 increases in a cross section cut along a plane parallel to the first direction. In other words, the width of the second recess 50B in the second direction may become smaller as the distance from the second surface 42 on which the second recess 50B is provided increases in a cross section cut along a plane parallel to the first direction. As shown in Fig. 5 , the shape of the second recess 50B may be a curved shape that is convex from the second surface 42 toward the first surface 41 in a cross section cut along the first direction.

[0025] The recess 50 can be formed by blasting the first surface 41 or the second surface 42. By forming the recess 50 by blasting, the inner surface of the recess 50 can be formed into a curved shape, as shown in FIG.

[0026] In this embodiment, the opening areas of the plurality of recesses 50 are the same when the base 40A is viewed from above, but this is not limited thereto, and the opening areas of the plurality of recesses 50 may be different from one another. An example in which the opening areas of the plurality of recesses 50 are not the same will be described in embodiment 2. In this embodiment, the depths of the plurality of recesses 50 are the same, but this is not limited thereto, and the depths of the plurality of recesses 50 may be different from one another.

[0027] In the substrate 30A according to the present disclosure, the shape of the recess 50 is not limited to the above-described shape as long as the recess 50 is formed on each of the first surface 41 and the second surface 42. The shape of the recess 50 may be, for example, a cylindrical shape.

[0028] The recess 50 is filled with a metal member 51 having a thermal conductivity higher than that of the base 40A. The metal member 51 is not particularly limited as long as it has a thermal conductivity higher than that of the base 40A. For example, when the base 40A is made of an aluminum nitride sintered body, the metal member 51 may be copper, copper-tungsten, copper-molybdenum, aluminum, or the like. Filling the recess 50 with the metal member 51 improves the thermal conductivity of the substrate 30A. The metal member 51 can be filled into the recess 50 by a plating method such as electrolytic plating or a metallization method. In the following description, the metal member 51 located inside the first recess 50A may be referred to as the first metal member 51A, and the metal member 51 located inside the second recess 50B may be referred to as the second metal member 51B.

[0029] In a planar perspective view of the base 40A, the first recesses 50A formed on the first surface 41 and the second recesses 50B formed on the second surface 42 may be alternately arranged in at least one direction perpendicular to the first direction. In the base 40A of this embodiment, the centers of the openings of the first recesses 50A and the centers of the openings of the second recesses 50B are alternately arranged on the line L shown in FIG. 4 . This configuration allows the multiple recesses 50 to be evenly arranged on the first surface 41 and the second surface 42, reducing the likelihood of variations in the overall heat dissipation performance of the base 40A. Furthermore, this configuration allows the first recesses 50A formed on the first surface 41 to be located in a region that does not overlap with the second recesses 50B formed on the second surface 42 when the substrate 30A is viewed from above. This prevents electrical connection between the first conductor film layer 31 and the second conductor film layer 32. In this specification, the term "perpendicular" does not require strict perpendicularity.

[0030] The base 40A may have at least one set of recesses 50 in which a portion of a first recess 50A overlaps a second recess 50B when viewed from above in a direction perpendicular to the first direction. This configuration may be realized, for example, as shown in Fig. 5, by forming the first recess 50A on the first surface 41 deeper than the center of the base 40A in the first direction, and by forming the second recess 50B on the second surface 42 deeper than the center of the base 40A in the first direction. With this configuration, the volume of the recess 50 formed in the base 40A can be increased, thereby improving the thermal conductivity of the substrate 30A.

[0031] The substrate 30A according to one embodiment of the present disclosure may have thin film layers (not shown) on the surfaces of the recess 50, the first surface 41, and the second surface 42. The thin film layers may be composed of, for example, tantalum nitride, nickel-chromium, nickel-chromium-silicon, tungsten-silicon, molybdenum-silicon, tungsten, molybdenum, titanium, or chromium. The thin film layers can be formed by deposition, ion plating, sputtering, or other techniques. Forming the thin film layers on the surfaces of the recess 50, the first surface 41, and the second surface 42 improves the bonding between the inner surface of the recess 50 and the metal member 51, the bonding between the first surface 41 and the first conductive film layer 31, the bonding between the metal member 51 and the first conductive film layer 31, the bonding between the second surface 42 and the second conductive film layer 32, and the bonding between the metal member 51 and the second conductive film layer 32.

[0032] As shown in FIG. 5 , the first conductor film layer 31 is located on the first surface 41 of the base 40A. The first conductor film layer 31 is connected to the first metal member 51A filling the first recess 50A. As shown in FIG. 5 , the first conductor film layer 31 is connected to each of the first metal members 51A filling the multiple first recesses 50A provided on the first surface 41. The first conductor film layer 31 is made of a material with excellent electrical conductivity, such as copper. The first conductor film layer 31 is formed on the first surface 41 in two separate regions. One of the first conductor film layers 31 is on which the electronic element 21 is mounted. The other first conductor film layer 31 is used as a connection portion for a connection member 33, such as a bonding wire, and electrically connects the electronic element 21 to a wiring conductor of a wiring board (not shown). As will be described later, since the first conductor film layer 31 is composed of a thin film, in this specification, "the electronic element 21 is mounted on the first conductor film layer 31" is explained as being synonymous with "the electronic element 21 is mounted on the electronic element mounting portion 41a of the first surface 41."

[0033] The first conductor film layer 31 is formed on the first surface 41 and has a thermal conductivity higher than that of the base 40A. The first conductor film layer 31 is not particularly limited as long as it has a thermal conductivity higher than that of the base 40A. For example, when the base 40A is made of an aluminum nitride sintered body, the first conductor film layer 31 may be made of copper, copper-tungsten, copper-molybdenum, aluminum, or the like. Forming the first conductor film layer 31 on the first surface 41 improves the thermal conductivity of the substrate 30A. The first conductor film layer 31 can be formed on the first surface 41 by a plating method such as electrolytic plating or a metallization method. As described above, a thin film layer (not shown) may be formed on the surface of the first surface 41. When the first conductor film layer 31 and the metal member 51 are made of the same material, for example, copper, heat can be transferred effectively from the first conductor film layer 31 to the metal member 51. The electronic element 21 is fixed to one of the first conductive film layers 31 using a bonding material such as In or Au-Sn, and then mounted on the substrate 30A by electrically connecting the electrodes of the electronic element 21 to the other first conductive film layer 31 via a connecting member 33 such as a bonding wire.

[0034] A plating layer may be formed on the upper surface of the first conductive film layer 31. The plating layer may be made of a metal that has excellent corrosion resistance and connectivity with the connecting member 33, such as nickel, copper, gold, or silver. The plating layer may be formed, for example, by sequentially depositing a nickel plating layer having a thickness of 0.5 to 5 μm and a gold plating layer having a thickness of 0.1 to 3 μm. This reduces the possibility of corrosion of the first conductive film layer 31 and strengthens the adhesion between the first conductive film layer 31 and the electronic element 21, as well as the bond between the first conductive film layer 31 and the connecting member 33.

[0035] The second conductor film layer 32 is located on the second surface 42 of the base 40A. The second conductor film layer 32 may have the same material and configuration as the first conductor film layer 31. The second conductor film layer 32 is used to join to the metal plate 22. If the second conductor film layer 32 and the metal member 51 are made of the same material, for example, if the second conductor film layer 32 and the metal member 51 are made of copper, heat can be transferred well from the metal member 51 to the second conductor film layer 32.

[0036] Here, if the sum of the volume of the first metal member 51A filling the multiple first recesses 50A provided on the first surface 41 and the volume of the first conductor film layer 31 is significantly different from the sum of the volume of the second metal member 51B filling the multiple second recesses 50B provided on the second surface 42 and the volume of the second conductor film layer 32, the base 40A will warp due to the difference in thermal expansion coefficient between the base 40A and the metal member 51. Therefore, in the substrate 30A, the sum of the volume of the first metal member 51A filling the multiple first recesses 50A provided on the first surface 41 and the volume of the first conductor film layer 31 may be set to be 90 volume % or more and 110 volume % or less of the sum of the volume of the second metal member 51B filling the multiple second recesses 50B provided on the second surface 42 and the volume of the second conductor film layer 32. This reduces the amount of warping of the base 40A. When the substrate 30A does not have either the first conductor film layer 31 or the second conductor film layer 32, the sum of the volumes of the first metal members 51A filled in the multiple first recesses 50A provided on the first surface 41 may be set to be 90 volume % or more and 110 volume % or less of the sum of the volumes of the second metal members 51B filled in the multiple second recesses 50B provided on the second surface 42.

[0037] As described above, in the substrate 30A of this embodiment, the base 40A has a plurality of recesses 50 filled with metal members 51 on the first surface 41 and the second surface 42. This allows the volume of the metal members 51 included in the base 40A to be larger than in a base in which recesses 50 are formed on only one of the first surface 41 and the second surface 42. As a result, the thermal conductivity of the substrate 30A can be improved. Furthermore, the first surface 41 on which the electronic element 21 is mounted may be formed with recesses 50 whose width in the front-to-rear direction decreases as the distance from the first surface 41 increases in a cross section cut along a plane parallel to the up-down direction.

[0038] In the present embodiment, the substrate 30A has recesses 50 formed on the first surface 41 and the second surface 42 on which the electronic elements 21 are mounted. The width of the recesses 50 in the second direction decreases as the distance from the first surface 41 or the second surface 42 increases in a cross section cut along a plane parallel to the first direction. In other words, the diameter of the recesses 50 decreases as the distance from the first surface 41 or the second surface 42 increases in a cross section cut along a plane parallel to the first direction. This allows the surface area of ​​the recesses 50 to be larger than when the recesses 50 are rectangular parallelepiped-shaped, for example. As a result, heat is more easily transferred from the metal member 51 on the first surface 41 side to the base 40A, and from the base 40A to the metal member 51 on the second surface 42 side. This increases the thermal conductivity of the substrate 30A.

[0039] 5, the shape of the recess 50 is a curved shape that is convex from the surface on which the recess 50 is formed to the surface opposite the surface on a cross section cut in the first direction. This makes it possible to disperse stress applied to the surface on which the recess 50 is formed when a load in the first direction is applied to the substrate 30A. As a result, it is possible to reduce the possibility of the substrate 30A being damaged.

[0040] In the substrate 30A, the first metal member 51A filled in the first recess 50A formed on the first surface 41 side is in contact with the first conductor film layer 31, as shown in FIG. 5 . This makes it easier for heat conducted from the electronic element 21 to the first conductor film layer 31 to be conducted to the first metal member 51A. Furthermore, the second metal member 51B filled in the second recess 50B formed on the second surface 42 side is in contact with the second conductor film layer 32, as shown in FIG. 5 . This makes it easier for heat conducted to the base 40A to be conducted to the second conductor film layer 32 via the second metal member 51B. This improves the thermal conductivity of the substrate 30A.

[0041] In this embodiment, the substrate 30A is equipped with a laser diode as the electronic element 21, but the electronic element mounted on the substrate 30A is not limited to a laser diode. For example, the electronic element mounted on the substrate 30A may be a semiconductor element such as an IC chip or an LSI chip, or a piezoelectric element such as a quartz crystal oscillator or a piezoelectric oscillator.

[0042] [Embodiment 2] Another embodiment of the present disclosure will be described below. For convenience of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0043] Fig. 6 is a top view of the substrate 30B according to this embodiment. For ease of explanation, the electronic element mounting portion 41a and the recess 50 are indicated by dotted lines in Fig. 6, and the recess 50 formed on the second surface 42 is hatched. Fig. 7 is a view of the substrate 30B and the electronic element 21 as viewed from the third direction (front-rear direction). In Fig. 7, the recess 50 is indicated by dotted lines.

[0044] As shown in FIGS. 6 and 7, the substrate 30B includes a base body 40B instead of the base body 40A in the first embodiment.

[0045] The base 40B has a plurality of recesses 50 filled with metal members 51 formed on each of the first surface 41 and the second surface 42. In the base 40B, the opening diameter of the recesses 50 decreases as the position at which the recesses 50 are formed moves outward from the center in the second direction. As a result, in the substrate 30B, when viewed in a plan view, the opening area of ​​the recesses 50 increases from the outside in the second direction toward the electronic element mounting portion 41a. In other words, when viewed in a plan view, the opening area of ​​the recesses 50 provided in the electronic element mounting portion 41a or in a region close to the electronic element mounting portion 41a is larger than the opening area of ​​the recesses 50 provided in a region far from the electronic element mounting portion 41a.

[0046] With the above configuration, in the base 40B, heat is easily transferred from the first surface 41 to the interior of the base 40B in the electronic element mounting portion 41a or in a region close to the electronic element mounting portion 41a where the recess 50 with a large opening area is formed, and heat is easily transferred from the interior of the base 40B to the second surface 42. In other words, in the substrate 30B, the thermal conductivity is higher near the electronic element mounting portion 41a than at the outside. This makes it easier to efficiently transfer heat conducted from the electronic element 21 to the metal plate 22, making it easier to lower the temperature of the electronic element 21. If the size or shape of the electronic element 21 requires that the electronic element 21 be mounted only at the center in the third direction on the first surface 41 of the substrate 30B, in this case, the opening diameter of the recess 50 of the base 40B may decrease from the center in the third direction on the first surface 41 toward the outside.

[0047] [Embodiment 3] Another embodiment of the present disclosure will be described below. Fig. 8 is a top view of a substrate 30C according to this embodiment. For ease of explanation, the recesses 50 formed on the second surface 42 are shown hatched in Fig. 8. Fig. 9 is a view of the substrate 30C and the electronic element 21 as viewed from a third direction. In Fig. 9, the recesses 50 are indicated by dotted lines.

[0048] As shown in FIGS. 8 and 9, the substrate 30C includes a base body 40C instead of the base body 40A in the first embodiment.

[0049] The base 40C has a plurality of recesses 50 filled with metal members 51 on the first surface 41 and the second surface 42. In the base 40C of this embodiment, as shown in FIG. 9 , the second recesses 50B provided on the second surface 42, which is located farther from the heat-generating electronic element 21 than the first surface 41, are deeper than the first recesses 50A provided on the first surface. This reduces the distance between the first recesses 50A provided on the first surface 41 and the second recesses 50B provided on the second surface 42, facilitating heat transfer from the first metal member 51A filled in the first recesses 50A to the second metal member 51B filled in the second recesses 50B. As a result, the heat dissipation performance of the substrate 30C can be improved. The depth of the first recess 50A indicates the distance from the first surface 41 to the bottom of the first recess 50A, and the depth of the second recess 50B indicates the distance in the Z-axis direction from the second surface 42 to the bottom of the second recess 50B.

[0050] As described in the first embodiment, if the sum of the volume of the first metal member 51A filling the multiple first recesses 50A provided on the first surface 41 and the volume of the first conductor film layer 31 is significantly different from the sum of the volume of the second metal member 51B filling the multiple second recesses 50B provided on the second surface 42 and the volume of the second conductor film layer 32, the base 40C will warp. Therefore, as shown in FIG. 9 , the base 40C in this embodiment may be configured so that the opening area of ​​the second recess 50B formed on the second surface 42 is smaller than the opening area of ​​the first recess 50A formed on the first surface 41. This prevents the volume of the first recess 50A formed on the first surface 41 from differing significantly from the volume of the second recess 50B formed on the second surface 42. This reduces the amount of warping of the base 40C.

[0051] [Embodiment 4] Another embodiment of the present disclosure will be described below. Fig. 10 is a top view of a substrate 30D in this embodiment. Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 10. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 10.

[0052] As shown in FIGS. 10 to 12, the substrate 30D includes a base body 40D instead of the base body 40A in the first embodiment.

[0053] The base 40D has a plurality of recesses 60 filled with a metal member 51 formed on each of the first surface 41 and the second surface 42. As shown in FIGS. 10 and 11 , the recesses 60 are slits extending in a second direction, which is perpendicular to the first direction. As shown in FIG. 10 , the recesses 60 may be provided in a region overlapping the first conductor film layer 31 when the base 40D is viewed from above. In this embodiment, the recesses 60 are formed so that their length in the second direction is the same as the length of the first conductor film layer 31 in the second direction. However, the length may be shorter than the length of the first conductor film layer 31 in the second direction. In the following description, the recesses 60 having an opening in the first surface 41 may be referred to as a first recess 60A, and the recesses 60 having an opening in the second surface 42 may be referred to as a second recess 60B.

[0054] 12, the first recess 60A provided on the first surface 41 may have a cross-sectional shape cut along a plane perpendicular to the second direction such that the length in the third direction decreases with increasing distance from the first surface 41. This allows the surface area of ​​the first recess 60A to be increased compared to when the cross-sectional shape cut along a plane perpendicular to the second direction is rectangular. As a result, heat is more easily transferred from the first metal member 51A to the base 40D. This allows the thermal conductivity of the substrate 30D to be increased.

[0055] The second recess 60B provided in the second surface 42 may have a cross-sectional shape cut by a plane perpendicular to the second direction such that the length in the third direction decreases with increasing distance from the second surface 42. As in the above embodiment, the slits can be formed by blasting the first surface 41 and the second surface 42 of the base 40D.

[0056] 10 , in a planar perspective view of the base 40D, the first recess 60A provided on the first surface 41 may be provided in a region that does not overlap with the second recess 60B provided on the second surface 42. This prevents the first conductor film layer 31 and the second conductor film layer 32 from being electrically connected to each other.

[0057] In the present embodiment, the recess 60 is a slit extending in the second direction (left-right direction), but is not limited to this. The recess 60 may be a slit extending in any direction perpendicular to the up-down direction, for example, a slit extending in the third direction (front-rear direction).

[0058] In the substrate 30D according to the present disclosure, the shape of the recess 60 is not limited to the above-described shape as long as the recess 60 is formed on each of the first surface 41 and the second surface 42. The shape of the recess 60 may be, for example, rectangular or triangular in cross section perpendicular to the longitudinal direction.

[0059] In the substrate 30D of the present embodiment, the recesses formed on the first surface 41 and the second surface 42 are slits, but this is not limited thereto. In a substrate according to one aspect of the present disclosure, a recess 50 having a cavity structure may be formed on one of the first surface 41 and the second surface 42, and a recess 60 having a slit structure may be formed on the other surface.

[0060] [Embodiment 5] Another embodiment of the present disclosure will be described below. Fig. 13 is a top view of a substrate 30E according to this embodiment. For ease of explanation, in Fig. 13, the electronic element mounting portion 41a and the recess 50 are indicated by dotted lines, and the recess 50 formed on the second surface 42 is illustrated by hatching. Fig. 14 is a view of the substrate 30E and the electronic element 21 as viewed from a third direction (front-rear direction). In Fig. 14, the recess 50 is indicated by dotted lines.

[0061] As shown in FIGS. 10 to 12, the substrate 30E includes a base body 40E instead of the base body 40A in the first embodiment.

[0062] The base 40E has a plurality of recesses 50 formed on each of the first surface 41 and the second surface 42, each of which is filled with a metal member 51. As shown in Figures 13 and 14, the recesses 50 have a rectangular parallelepiped shape extending along the first direction. The interior of the recesses 50 is filled with a metal member 51 having a thermal conductivity higher than that of the base 40E.

[0063] With the above configuration, in the substrate 30E of this embodiment, the base 40E has a plurality of recesses 50 filled with metal members 51 on the first surface 41 and the second surface 42. This allows the volume of the metal members 51 included in the base 40E to be larger than in a base in which the recesses 50 are formed on only one of the first surface 41 and the second surface 42. As a result, the thermal conductivity of the substrate 30E can be improved.

[0064] In this embodiment, the opening areas of the plurality of recesses 50 are the same when the base 40E is viewed from above, but this is not limited thereto and the opening areas of the plurality of recesses 50 may be different from one another. In this embodiment, the depths of the plurality of recesses 50 are the same, but this is not limited thereto and the depths of the plurality of recesses 50 may be different from one another.

[0065] A substrate according to aspect 1 of the present disclosure comprises a base body including a first surface, a second surface located opposite the first surface, at least one first recess opening into the first surface, and at least one second recess having an opening in the second surface, a first metal member located inside the first recess, and a second metal member located inside the second recess, wherein the thermal conductivity of the first metal member and the thermal conductivity of the second metal member are higher than the thermal conductivity of the base body.

[0066] A substrate according to a second aspect of the present disclosure may be the substrate of the first aspect described above, wherein the base body has a plurality of the first recesses and a plurality of the second recesses.

[0067] A substrate according to a third aspect of the present disclosure is the substrate of the first or second aspect above, wherein at least one of the first recess and the second recess may have an opening having a circular shape in a plan view.

[0068] A substrate according to aspect 4 of the present disclosure may be any of aspects 1 to 3 above, wherein the base has a plurality of the first recesses and a plurality of the second recesses, the first recesses being arranged in a grid pattern on the first surface, and the second recesses being arranged in a grid pattern on the second surface.

[0069] The substrate of aspect 5 of the present disclosure may be configured in the above-mentioned aspect 4 such that, when viewed from a plane, the first recesses and the second recesses are arranged alternately in at least one direction perpendicular to a first direction that is perpendicular to the first surface and the second surface.

[0070] A substrate according to aspect 6 of the present disclosure may be configured in any one of aspects 1 to 5 above such that, when viewed from above in a perspective view, the first recess does not overlap with the second recess.

[0071] The substrate of aspect 7 of the present disclosure may be configured such that, in any of aspects 1 to 6 above, a portion of the first recess overlaps with the second recess when viewed from a direction perpendicular to a first direction perpendicular to the first surface and the second surface.

[0072] A substrate according to aspect 8 of the present disclosure may be configured such that, in any of aspects 1 to 7 above, the sum of the volumes of the first metal members filled inside the first recesses is 90 volume % or more and 110 volume % or less of the sum of the volumes of the second metal members filled inside the second recesses.

[0073] A substrate according to aspect 9 of the present disclosure may be configured in any one of aspects 1 to 7 above, further comprising a first conductor film layer located on the first surface and a second conductor film layer located on the second surface, wherein the sum of the volume of the first metal member filled inside the first recess and the volume of the first conductor film layer is 90 volume % or more and 110 volume % or less of the sum of the volume of the second metal member filled inside the second recess and the volume of the second conductor film layer.

[0074] A substrate according to aspect 10 of the present disclosure may be any of aspects 1 to 9 above, wherein in at least one cross section cut in a first direction perpendicular to the first surface and the second surface, the width of the first recess in a direction parallel to the first surface decreases as the distance from the first surface increases, and the width of the second recess in a direction parallel to the first surface decreases as the distance from the second surface increases.

[0075] In the substrate of aspect 11 of the present disclosure, in the above-mentioned aspect 10, the shapes of the first recess and the second recess may be curved from the surface of the first surface or the second surface on which the first recess or the second recess is provided to the opposite surface in at least one cross section cut in the first direction.

[0076] A substrate according to aspect 12 of the present disclosure may be configured such that, in any of aspects 1 to 11 above, the base has an electronic element mounting portion on the first surface, and the opening area of ​​the second recess is smaller than the opening area of ​​the first recess.

[0077] A substrate according to aspect 13 of the present disclosure may be configured in any one of aspects 1 to 12 above, wherein the base has an electronic element mounting portion on the first surface, and the depth of the second recess is greater than the depth of the first recess.

[0078] A substrate according to aspect 14 of the present disclosure, in any of aspects 1 and 6 to 13 above, may have at least one of the first recess and the second recess as a slit extending in a second direction perpendicular to a first direction in which the first surface and the second surface face each other.

[0079] A substrate according to aspect 15 of the present disclosure may be configured in the above-described aspect 14 such that, when the substrate is viewed in plan view, the first recess does not overlap with the second recess.

[0080] An electronic device according to a sixteenth aspect of the present disclosure includes an electronic element mounted on the substrate according to any one of the first to fifteenth aspects above.

[0081] An electronic module according to aspect 17 of the present disclosure includes the electronic device according to aspect 16 housed in a case.

[0082] A module device according to an eighteenth aspect of the present disclosure includes the electronic module according to the seventeenth aspect mounted on a module substrate or a housing.

[0083] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0084] REFERENCE SIGNS LIST 1 module device 2 housing 10 electronic module 11 case 20 electronic device 21 electronic element 30A, 30B, 30C, 30D, 30E substrate 31 first conductor film layer 32 second conductor film layer 40A, 40B, 40C, 40D, 40E base body 41a electronic element mounting portion 50, 60 recess 50A, 60A first recess 50B, 60B second recess 51 metal member 51A first metal member 51B second metal member

Claims

1. a base including a first surface, a second surface located opposite to the first surface, at least one first recess having an opening in the first surface, and at least one second recess having an opening in the second surface; a first metal member located inside the first recess; a second metal member located inside the second recess, A substrate, wherein the thermal conductivity of the first metal member and the thermal conductivity of the second metal member are higher than the thermal conductivity of the base.

2. The substrate of claim 1 , wherein the base body has a plurality of the first recesses and a plurality of the second recesses.

3. The substrate according to claim 1 , wherein at least one of the first recess and the second recess has an opening that is circular in plan view.

4. the base body has a plurality of the first recesses and a plurality of the second recesses, The first recesses are arranged in a lattice pattern on the first surface, The substrate according to claim 1 , wherein the second recesses are arranged in a lattice pattern on the second surface.

5. The substrate according to claim 4, wherein, when the substrate is viewed from above, the first recesses and the second recesses are arranged alternately in at least one direction perpendicular to a first direction perpendicular to the first surface and the second surface.

6. The substrate according to claim 1 , wherein the first recess does not overlap with the second recess when the substrate is seen through a plan view.

7. The substrate according to claim 1 , wherein when the base is viewed from a direction perpendicular to a first direction perpendicular to the first surface and the second surface, a portion of the first recess overlaps with the second recess.

8. The substrate of claim 1 , wherein the sum of the volumes of the first metal members filled inside the first recess is 90 volume % or more and 110 volume % or less of the sum of the volumes of the second metal members filled inside the second recess.

9. a first conductor film layer located on the first surface; a second conductor film layer located on the second surface, The substrate of claim 1, wherein the sum of the volume of the first metal member filled inside the first recess and the volume of the first conductor film layer is 90 volume % or more and 110 volume % or less of the sum of the volume of the second metal member filled inside the second recess and the volume of the second conductor film layer.

10. 2. The substrate of claim 1, wherein in at least one cross section cut in a first direction perpendicular to the first surface and the second surface, a width of the first recess in a direction parallel to the first surface decreases as the distance from the first surface increases, and a width of the second recess in a direction parallel to the first surface decreases as the distance from the second surface increases.

11. The substrate of claim 10, wherein the shapes of the first recess and the second recess are curved from the surface of the first surface or the second surface on which the first recess or the second recess is provided to the opposite surface in at least one cross section cut in the first direction.

12. the base body has an electronic element mounting portion on the first surface, The substrate according to claim 1 , wherein an opening area of ​​the second recess is smaller than an opening area of ​​the first recess.

13. the base body has an electronic element mounting portion on the first surface, The substrate of claim 1 , wherein the second recess has a depth greater than a depth of the first recess.

14. The substrate according to claim 1 , wherein at least one of the first recess and the second recess is a slit extending in a second direction perpendicular to a first direction in which the first surface and the second surface face each other.

15. The substrate according to claim 14 , wherein the first recess does not overlap with the second recess when the substrate is seen through a plan view.

16. An electronic device comprising the substrate according to claim 1 and an electronic element mounted thereon.

17. An electronic module comprising the electronic device according to claim 16 housed in a case.

18. A module device comprising the electronic module according to claim 17 mounted on a module substrate or a housing.