Electronic mounting substrate and electronic device

Abstract

An electronic element mounting substrate includes a first substrate that has a first main surface, has a rectangular shape, and has a mounting portion for an electronic element on the first main surface, and a second substrate that is located on a second main surface opposite to the first main surface, is made of a carbon material, has a rectangular shape, has a third main surface facing the second main surface and a fourth main surface opposite to the third main surface, in which the third main surface or the fourth main surface has heat conduction in a longitudinal direction greater than heat conduction in a direction perpendicular to the longitudinal direction, and that has a recessed portion on the fourth main surface.

1 . An electronic element mounting substrate comprising:
 a first substrate that comprises a first main surface, has a rectangular shape, and comprises a mounting portion for an electronic element on the first main surface; and   a second substrate that is located on a second main surface opposite to the first main surface, is made of a carbon material, has a rectangular shape, comprises a third main surface facing the second main surface and a fourth main surface opposite to the third main surface, wherein   the third main surface or the fourth main surface has heat conduction in a longitudinal direction greater than heat conduction in a direction perpendicular to the longitudinal direction, and   the second substrate comprises a recessed portion on the fourth main surface.   
     
     
         2 . The electronic element mounting substrate according to  claim 1 , wherein
 the recessed portion overlaps the mounting portion in perspective plan view.   
     
     
         3 . The electronic element mounting substrate according to  claim 1 , further comprising
 a third substrate that is located on the fourth main surface, has a rectangular shape, comprises a fifth main surface facing the fourth main surface and a sixth main surface opposite to the fifth main surface, and comprises a through-hole penetrating in a thickness direction, and facing the recessed portion.   
     
     
         4 . The electronic element mounting substrate according to  claim 3 , wherein
 the through-hole overlaps the mounting portion in perspective plan view.   
     
     
         5 . An electronic device comprising:
 the electronic element mounting substrate according to  claim 1 ;   an electronic element mounted on the mounting portion of the electronic element mounting substrate; and   a heat transfer member in the recessed portion.   
     
     
         6 . The electronic element mounting substrate according to  claim 2 , further comprising
 a third substrate that is located on the fourth main surface, has a rectangular shape, comprises a fifth main surface facing the fourth main surface and a sixth main surface opposite to the fifth main surface, and comprises a through-hole penetrating in a thickness direction, and facing the recessed portion.   
     
     
         7 . The electronic element mounting substrate according to  claim 6 , wherein
 the through-hole overlaps the mounting portion in perspective plan view.   
     
     
         8 . An electronic device comprising:
 the electronic element mounting substrate according to  claim 2 ;   an electronic element mounted on the mounting portion of the electronic element mounting substrate; and   a heat transfer member in the recessed portion.   
     
     
         9 . An electronic device comprising:
 the electronic element mounting substrate according to  claim 3 ;   an electronic element mounted on the mounting portion of the electronic element mounting substrate; and   a heat transfer member in the recessed portion.   
     
     
         10 . An electronic device comprising:
 the electronic element mounting substrate according to  claim 4 ;   an electronic element mounted on the mounting portion of the electronic element mounting substrate; and   a heat transfer member in the recessed portion.   
     
     
         11 . An electronic device comprising:
 the electronic element mounting substrate according to  claim 6 ;   an electronic element mounted on the mounting portion of the electronic element mounting substrate; and   a heat transfer member in the recessed portion.   
     
     
         12 . An electronic device comprising:
 the electronic element mounting substrate according to  claim 7 ;   an electronic element mounted on the mounting portion of the electronic element mounting substrate; and   a heat transfer member in the recessed portion.