Substrate, electronic device, electronic module, and module device

Abstract

The present invention improves thermal conductivity. This invention is provided with a base body including: a first surface; and a second surface located on the opposite side as the first surface. The base body has at least one recess provided in the first surface. The interior of the recess is filled with a metal member having a thermal conductivity higher than the thermal conductivity of the base body. In a cross-section cut in a first direction orthogonal to the first surface and to the second surface, the width of the recess in a direction parallel to the first surface decreases as the distance from the surface, of the first surface or the second surface, where the recess is provided, increases.

Description

Substrate, electronic device, electronic module and module device

[0001] The present disclosure relates to a substrate on which components such as electronic elements are 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 and a second surface located opposite the first surface, the base body having at least one recess provided on at least one of the first surface and the second surface, the interior of the recess being filled with a metal member having a thermal conductivity higher than that of the base, and in at least one cross section cut in a first direction perpendicular to the first surface and the second surface, the width of the recess in a direction parallel to the first surface decreases as the distance from the surface of the first surface or the second surface on which the recess is provided increases.

[0005] FIG. 1 is a perspective view of a module device according to a first embodiment of the present disclosure. FIG. 2 is a top view of the module device. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a top view of a substrate according to a first embodiment of the present disclosure. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4. FIG. 6 is a top view of a substrate according to a second embodiment of the present disclosure. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 7 is a top view of a substrate according to a third embodiment of the present disclosure. FIG. 8 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 8 is a cross-sectional view taken along line XX in FIG. 8. FIG. 9 is a top view of a substrate according to a fourth embodiment of the present disclosure. FIG. 10 is a view of a substrate and electronic elements according to the fourth embodiment of the present disclosure, viewed from the Y-axis direction. FIG. 11 is a top view of a substrate according to a fifth embodiment of the present disclosure. FIG. 11 is a view of a substrate and electronic elements according to the fifth embodiment of the present disclosure, 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 may be 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, an electronic element mounting portion 41a and a recess 50, which will be described later, are indicated by dotted lines in FIG. 4. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4. The electronic element 21 is also illustrated in FIG. 5. The recess 50 is indicated by dotted lines in FIG. 4. As shown in FIGS. 4 and 5, the substrate 30A includes a base 40A, a first conductor film layer 31, a second conductor film layer 32, and a metal member 51.

[0016] The base 40A may be composed of a single layer or multiple layers. The base 40A in this embodiment 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, and a second surface 42 located on the opposite side of the first surface. The first surface 41 and the second surface 42 face each other. As shown in FIG. 4 , the first surface 41 has an electronic element mounting portion 41 a on which the electronic element 21 is mounted, at the center in the second direction (left-right direction).

[0017] The shape of the base body 40A when viewed from above is not particularly limited and may be, for example, rectangular, circular, etc. The base body 40A in this embodiment has a rectangular shape when viewed from above.

[0018] 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.

[0019] The base 40A has at least one recess 50 on the first surface 41. In this embodiment, the base 40A has multiple recesses 50 on the first surface 41. The recess 50 may have a cavity structure. The opening of the recess 50 may be circular when the substrate 30A is viewed in a plane from the Z-axis direction. The recess 50 has a bottom. When the base 40A has multiple recesses 50, the arrangement of the multiple recesses 50 is not particularly limited. For example, as shown in FIG. 4, the multiple recesses 50 may be arranged so that four adjacent recesses 50 are located at the vertices of a rectangle. In other words, the multiple recesses 50 may be arranged in a lattice pattern. As a result, when the substrate 30A is viewed in a plane, the multiple recesses 50 are evenly arranged, making it less likely that variations in the heat dissipation performance of the substrate 30A will occur.

[0020] As shown in FIG. 5 , 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, the recess 50 becomes narrower as the distance from the first surface 41 increases. In other words, in a cross section cut along a plane parallel to the first direction, the width of the recess 50 in the second direction decreases as the distance from the first surface 41 on which the recess 50 is provided increases. As shown in FIG. 5 , the shape of the recess 50 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 cross section of the recess 50 cut along a plane parallel to the first direction may be an elliptical hemisphere. In this specification, the terms "flat" or "planar" do not require that the recess 50 be strictly flat or planar.

[0021] The recess 50 can be formed by blasting the first surface 41. 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.

[0022] 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.

[0023] The interior of 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 material of the base 40A is an aluminum nitride sintered body, the metal member 51 may be copper, copper-tungsten, copper-molybdenum, aluminum, or the like. By filling the interior of the recess 50 with the metal member 51, the thermal conductivity of the substrate 30A can be improved. The metal member 51 can be filled into the recess 50 by a plating method such as electrolytic plating, or a metallization method.

[0024] The substrate 30A according to one embodiment of the present disclosure may have a thin film layer (not shown) on the surface of the recess 50 and the surface of the first surface 41. The thin film layer 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 layer can be formed by a deposition method, an ion plating method, a sputtering method, or another forming technique. The formation of the thin film layer on the surface of the recess 50 facilitates filling the recess 50 with the metal member 51 and forming the first conductive film layer 31 on the first surface 41, thereby improving 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, and the bonding between the metal member 51 and the first conductive film layer 31.

[0025] Here, if the volume ratio of the metal members 51 filled into the multiple recesses 50 becomes large relative to the volume of the base 40A including the recesses 50, the base 40A will warp due to the difference in thermal expansion coefficient between the base 40A and the metal members 51. When the base 40A warps, the contact area between the metal plate 22 and the base 40A decreases. As a result, heat transfer from the base 40A to the metal plate 22 becomes more difficult, and the heat dissipation performance of the electronic device 20 decreases. Therefore, in the substrate 30A according to one aspect of the present disclosure, the sum of the volumes of the metal members 51 filled into the multiple recesses 50 may be set to 10% or less of the volume of the base 40A including the recesses 50. This reduces the amount of warping of the base 40A, thereby preventing a decrease in the heat dissipation performance of the electronic device 20. When there is only one recess 50, the sum of the volumes of the metal members 51 refers to the volume of the metal member 51 filled in that recess 50.

[0026] 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 metal members 51 filled in the recesses 50. As shown in FIG. 5 , the first conductor film layer 31 is connected to each of the metal members 51 filled in the multiple recesses 50 formed in the base 40A. 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 has an electronic element 21 mounted thereon. 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."

[0027] 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.

[0028] 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.

[0029] 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.

[0030] As described above, the substrate 30A in this embodiment has a recess 50 formed on the first surface on which the electronic element 21 is mounted, the recess 50 having a width in the second direction that decreases with increasing distance from the first surface 41 in a cross section cut along a plane parallel to the first direction. This allows the surface area of ​​the recess 50 to be increased compared to when the recess 50 is rectangular. As a result, heat is more easily transferred from the metal member 51 to the base 40A. This allows the thermal conductivity of the substrate 30A to be increased. Furthermore, the first surface 41 on which the electronic element 21 is mounted may have a recess 50 having a width in the front-to-rear direction that decreases with increasing distance from the first surface 41 in a cross section cut along a plane parallel to the first direction.

[0031] Here, if the recess 50 is formed in a rectangular parallelepiped shape along the first direction, when a load parallel to the first direction is applied to the substrate 30A, stress concentrates at the corners of the rectangular parallelepiped shape, making the substrate more susceptible to damage. Therefore, as shown in FIG. 5 , the shape of the recess 50 is a curved shape that is convex from the first surface 41 to the second surface 42 in a cross section cut in the first direction. This makes it possible to disperse the 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, the possibility of damage to the substrate 30A can be reduced.

[0032] 5, in the substrate 30A, the metal member 51 filled in the recess 50 is in contact with the first conductive film layer 31. This makes it easier for heat conducted from the electronic element 21 to the first conductive film layer 31 to be conducted to the metal member 51. This improves the thermal conductivity of the substrate 30A.

[0033] 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.

[0034] [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.

[0035] Fig. 6 is a top view of the substrate 30B in this embodiment. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. Fig. 7 also shows the electronic element 21.

[0036] 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.

[0037] The base 40B has a plurality of recesses 50 filled with metal members 51 formed on the first surface 41. In the base 40B, the opening diameter of the recesses 50 decreases from the center in the second direction of the first surface 41 on which the electronic element 21 is mounted toward the outside. As a result, in the substrate 30B, 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. Furthermore, in the base 40B, the opening diameter of the recesses 50 decreases from the center in the third direction of the first surface 41 on which the electronic element 21 is mounted toward the outside. As a result, in the substrate 30B, in a plan view, the opening area of ​​the recesses 50 increases from the outside in the third direction toward the electronic element mounting portion 41a. Due to the above-mentioned configuration, when viewed in a plane, the opening area of ​​the recess 50 provided in the electronic element mounting portion 41a or in an area close to the electronic element mounting portion 41a of the base 40B is larger than the opening area of ​​the recess 50 provided in an area far from the electronic element mounting portion 41a.

[0038] With the above-described configuration, the base 40B facilitates heat transfer to the interior of the base 40B in the electronic element mounting portion 41a where the recess 50 with a large opening area is formed or in the region close to the electronic element mounting portion 41a. In other words, the substrate 30B has a higher thermal conductivity near the electronic element mounting portion 41a than at the outer edge when viewed from above. This facilitates efficient transfer of heat conducted from the electronic element 21 to the metal plate 22, making it easier to lower the temperature of the electronic element 21.

[0039] [Embodiment 3] Another embodiment of the present disclosure will be described below. Fig. 8 is a top view of a substrate 30C in this embodiment. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. Fig. 10 is a cross-sectional view taken along line XX in Fig. 8.

[0040] As shown in FIGS. 8 to 10, the substrate 30C includes a base body 40C instead of the base body 40A in the first embodiment.

[0041] The base 40C has a plurality of recesses 60 formed in the first surface 41, each recess 60 being filled with a metal member 51. As shown in FIGS. 8 and 9 , the recesses 60 are slits extending in a second direction (left-right direction) perpendicular to the first direction (up-down direction). As shown in FIG. 8 , the recesses 60 may be provided in a region overlapping the first conductor film layer 31 when the base 40C is viewed from above. In this embodiment, the recesses 60 are formed so that the length in the second direction is the same as the length in the second direction of the first conductor film layer 31, but may be shorter than the length in the second direction of the first conductor film layer 31. In this specification, the term "vertical" does not require strict perpendicularity.

[0042] 10 , in a cross section of the recess 60 cut along a plane perpendicular to the second direction, the length in the third direction (front-rear direction) decreases as the distance from the first surface 41 increases. This allows the surface area of ​​the recess 60 to be increased compared to, for example, a case in which the cross section cut along a plane perpendicular to the second direction has a rectangular shape. As a result, heat is more easily transferred from the metal member 51 to the base 40C. This allows the thermal conductivity of the substrate 30C to be increased.

[0043] Although the recess 60 in this embodiment is a slit extending in the second direction, this is not limiting. The recess 60 may be a slit extending in any direction perpendicular to the first direction, for example, a slit extending in the third direction. As in the above embodiment, the slit can be formed by blasting the first surface 41 of the base 40C.

[0044] [Embodiment 4] Another embodiment of the present disclosure will be described below. Fig. 11 is a top view of a substrate 30D according to this embodiment. For ease of explanation, the recesses 50 formed on the second surface 42 are shown hatched in Fig. 11. Fig. 12 is a view of the substrate 30D and the electronic element 21 as viewed from the third direction (front-rear direction). In Fig. 12, the recesses 50 are indicated by dotted lines.

[0045] As shown in FIGS. 11 and 12, the substrate 30D includes a base body 40D instead of the base body 40A in the first embodiment.

[0046] The base 40D has a plurality of recesses 50 filled with a metal member 51 on the first surface 41 and the second surface 42. In the following description, the recesses 50 on the first surface 41 may be referred to as the first recess 50A, and the recesses 50 on the second surface 42 may be referred to as the second recess 50B. As shown in FIG. 11 , the base 40D may be arranged such that four adjacent recesses 50 on the first surface 41 and the second surface 42 are located at the vertices of a rectangle. In other words, the recesses 50 may be arranged in a lattice pattern. This allows the recesses 50 to be evenly spaced on the first surface 41 and the second surface 42 when viewed from above, thereby reducing variations in the heat dissipation performance of the substrate 30D. In the example shown in FIGS. 11 and 12 , the metal member 51 filling the second recess 50B formed on the second surface 42 of the substrate 30D is connected to the second conductor film layer 32.

[0047] In the base 40D, when viewed in plan, the first recesses 50A formed in the first surface 41 and the second recesses 50B formed in the second surface 42 may be alternately arranged in at least one direction perpendicular to the first direction. In the base 40D of this embodiment, the centers of the openings of the first recesses 50A formed in the first surface 41 and the centers of the openings of the second recesses 50B formed in the second surface 42 are alternately arranged on the straight line L shown in FIG. 11 . This configuration prevents the first recesses 50A and the second recesses 50B from being continuous with each other. This prevents electrical connection between the first conductor film layer 31 and the second conductor film layer 32.

[0048] The base 40D may have at least one set of recesses 50 in which a first recess 50A provided on the first surface partially overlaps a second recess 50B provided on the second surface when viewed from above in a direction perpendicular to the first direction. This configuration may be realized, for example, as shown in FIG. 12 , by forming the first recess 50A on the first surface 41 deeper than the center of the base 40D in the first direction, and by forming the second recess 50B on the second surface 42 deeper than the center of the base 40D in the first direction. With this configuration, the volume of the recess 50 formed in the base 40D can be increased, thereby improving the thermal conductivity of the substrate 30D.

[0049] Here, if the sum of the volume of the metal member 51 filling the plurality of first recesses 50A 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 metal member 51 filling the plurality of second recesses 50B on the second surface 42 and the volume of the second conductor film layer 32, the base 40D will warp due to the difference in thermal expansion coefficient between the base 40D and the metal member 51. Therefore, in the substrate 30D, the sum of the volume of the metal member 51 filling the plurality of first recesses 50A 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 metal member 51 filling the plurality of second recesses 50B on the second surface 42 and the volume of the second conductor film layer 32. This reduces the amount of warping of the base 40D. When the substrate 30D does not have either the first conductor film layer 31 or the second conductor film layer 32, the sum of the volumes of the metal members 51 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 metal members 51 filled in the multiple second recesses 50B provided on the second surface 42.

[0050] As described above, in the substrate 30D of this embodiment, the base 40D has a plurality of recesses 50 filled with the 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 40D to be larger than that of the base 40A of the first embodiment, thereby improving the thermal conductivity of the substrate 30D.

[0051] In the substrate 30D of the present embodiment, the recesses 50 formed on the first surface 41 and the second surface 42 have a cavity structure, but this is not limited to this. In the substrate 30D of one aspect of the present disclosure, a plurality of recesses 50 may be formed on one of the first surface 41 and the second surface 42, and the recesses 60 having a slit structure as described in embodiment 3 may be formed on the other surface. Furthermore, in the substrate 30D of one aspect of the present disclosure, the recesses 60 having a slit structure may be formed on the first surface 41 and the second surface 42.

[0052] [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, the recesses 50 formed on the second surface 42 are shown hatched in Fig. 13. Fig. 14 is a view of the substrate 30E and the electronic element 21 as viewed from the third direction (front-rear direction). In Fig. 14, the recesses 50 are indicated by dotted lines.

[0053] As shown in FIGS. 13 and 14, a substrate 30E includes a base body 40E instead of the base body 40A in the first embodiment.

[0054] The base 40E has a plurality of recesses 50 filled with metal members 51 on the first surface 41 and the second surface 42. In the base 40E of this embodiment, as shown in FIG. 14 , the second recesses 50B provided on the second surface 42, which are located farther from the heat-generating electronic element 21 than on the first surface 41, are deeper than the first recesses 50A provided on the first surface 41. 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 metal members 51 filled in the first recesses 50A provided on the first surface 41 to the metal members 51 filled in the second recesses 50B provided on the second surface 42. As a result, the heat dissipation properties of the substrate 30E can be improved. The depth of the recess 50 refers to the distance in the Z-axis direction from the first surface 41 or the second surface 42 on which the recess 50 is provided to the bottom of the recess 50 .

[0055] As described in the fourth embodiment, if the sum of the volume of the metal member 51 filling the plurality of 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 metal member 51 filling the plurality of second recesses 50B provided on the second surface 42 and the volume of the second conductor film layer 32, the base 40E will warp. Therefore, as shown in FIG. 14 , the base 40E 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 a large difference between the volume of the first recess 50A formed on the first surface 41 and the volume of the second recess 50B formed on the second surface 42. This reduces the amount of warping of the base 40E.

[0056] 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.

[0057] A substrate according to a first aspect of the present disclosure comprises a base body including a first surface and a second surface located opposite the first surface, the base body having at least one recess formed on at least one of the first surface and the second surface, the interior of the recess being filled with a metal member having a thermal conductivity higher than that of the base body, and in at least one cross section cut in a first direction perpendicular to the first surface and the second surface, the width of the recess in a direction parallel to the first surface decreases as the distance from the surface of the first surface or the second surface on which the recess is formed increases.

[0058] In the substrate of aspect 2 of the present disclosure, in the above-mentioned aspect 1, the shape of the recess may be curved from the surface on which the recess is provided to the opposite surface of the first surface or the second surface in at least one cross section cut in the first direction.

[0059] A substrate according to aspect 3 of the present disclosure may be the substrate of aspect 1 or 2 above, wherein the base body has the recess on only one of the first surface or the second surface.

[0060] A substrate according to aspect 4 of the present disclosure may be such that, in the above-described aspect 3, the sum of the volumes of the metal members filled inside the recesses is 10 volume % or less of the volume of the base including the recesses.

[0061] A substrate according to aspect 5 of the present disclosure may be such that, in aspect 3 or 4 above, the base has the recess on only one of the first surface or the second surface, and has a conductive film layer on the surface of the first surface or the second surface on which the recess is provided, and the metal member filled in the recess is in contact with the conductive film layer.

[0062] A substrate according to aspect 6 of the present disclosure may be the same as that of aspect 1 or 2 above, wherein the recess includes a first recess provided on the first surface and a second recess provided on the second surface.

[0063] A substrate according to aspect 7 of the present disclosure is, in the above-described aspect 6, wherein the recess includes at least one first recess provided on the first surface and at least one second recess provided on the second surface, and the sum of the volumes of the metal members filled inside the first recesses may be 90 volume % or more and 110 volume % or less of the sum of the volumes of the metal members filled inside the second recesses.

[0064] The substrate according to aspect 8 of the present disclosure, in the above-described aspect 6, further comprises a first conductor film layer located on the first surface and a second conductor film layer located on the second surface, wherein the recess includes at least one first recess provided on the first surface and at least one second recess provided on the second surface, and the sum of the volume of the metal member filled inside the first recess and the volume of the first conductor film layer may be 90 volume % or more and 110 volume % or less of the sum of the volume of the metal member filled inside the second recess and the volume of the second conductor film layer.

[0065] A substrate according to aspect 9 of the present disclosure may be configured as in any one of aspects 6 to 8 above, wherein the first recess and the second recess are not continuous.

[0066] A substrate according to aspect 10 of the present disclosure may be configured such that, in any of aspects 6 to 9 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.

[0067] A substrate according to aspect 11 of the present disclosure may be configured such that, in any of aspects 6 to 9 above, 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.

[0068] A substrate according to aspect 12 of the present disclosure is any one of aspects 1 to 11 above, wherein the opening of the recess may have a circular shape when viewed in plan.

[0069] In the substrate according to Aspect 13 of the present disclosure, in Aspect 12 above, a plurality of the recesses may be arranged in a grid pattern on the first surface or the second surface.

[0070] A substrate according to aspect 14 of the present disclosure may be configured as in any one of aspects 1 to 11 above, wherein the recess is a slit extending in a second direction perpendicular to the first direction.

[0071] An electronic device according to a fifteenth aspect of the present disclosure includes an electronic element mounted on the substrate according to any one of the first to fourteenth aspects.

[0072] An electronic module according to a sixteenth aspect of the present disclosure includes the electronic device according to the fifteenth aspect housed in a case.

[0073] A module device according to aspect 17 of the present disclosure includes the electronic module according to aspect 16 mounted on a module substrate or a housing.

[0074] 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 first recess 50B second recess 51 metal member

Claims

1. a substrate including a first surface and a second surface opposite the first surface; the base has at least one recess provided on at least one of the first surface and the second surface, the recess is filled with a metal member having a thermal conductivity higher than that of the base, A substrate, in at least one cross section cut in a first direction perpendicular to the first surface and the second surface, wherein the width of the recess in a direction parallel to the first surface decreases as the distance from the first surface or the second surface on which the recess is provided increases.

2. The substrate according to claim 1 , wherein the shape of the recess is curved from the surface on which the recess is provided to the opposite surface of the first surface or the second surface in at least one cross section cut in the first direction.

3. The substrate according to claim 1 , wherein the base body has the recess on only one of the first surface and the second surface.

4. 4. The substrate according to claim 3, wherein a sum of the volumes of the metal members filling the interiors of the recesses is 10 volume % or less with respect to a volume of the base body including the recesses.

5. the base has the recess on only one of the first surface and the second surface, a conductive film layer on one of the first surface and the second surface on which the recess is provided, The substrate according to claim 3 , wherein the metal member filled in the recess is in contact with the conductive film layer.

6. The substrate according to claim 1 , wherein the recess includes a first recess provided in the first surface and a second recess provided in the second surface.

7. The recess includes at least one first recess provided on the first surface and at least one second recess provided on the second surface, The substrate according to claim 6, wherein the sum of the volumes of the 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 metal members filled inside the second recess.

8. a first conductor film layer located on the first surface and a second conductor film layer located on the second surface, The recess includes at least one first recess provided on the first surface and at least one second recess provided on the second surface, The substrate according to claim 6, wherein the sum of the volume of the 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 metal member filled inside the second recess and the volume of the second conductor film layer.

9. The substrate according to claim 6 , wherein the first recess and the second recess are not continuous.

10. the base body has an electronic element mounting portion on the first surface, The substrate according to claim 6 , wherein an opening area of ​​the second recess is smaller than an opening area of ​​the first recess.

11. the base body has an electronic element mounting portion on the first surface, The substrate according to claim 6 , wherein the second recess is deeper than the first recess.

12. The substrate according to claim 1 , wherein the opening of the recess has a circular shape in a plan view.

13. The substrate according to claim 12 , wherein a plurality of the recesses are provided on the first surface or the second surface and are arranged in a lattice pattern.

14. The substrate according to claim 1 , wherein the recess is a slit extending in a second direction perpendicular to the first direction.

15. An electronic device comprising an electronic element mounted on the substrate according to claim 1 , 2 or 6 .

16. An electronic module comprising the electronic device according to claim 15 housed in a case.

17. A module device having the electronic module according to claim 16 mounted on a module substrate or a housing.