Electronic device

Abstract

An electronic device according to a present disclosure includes a semiconductor substrate, a chip, and a connection part. The chip has a different thermal expansion rate from that of the semiconductor substrate. The connection part includes a porous metal layer for connecting connection pads that are arranged on opposing principle surfaces of the semiconductor substrate and the chip.

What is claimed is: 
     
         1 . An electronic device comprising:
 a semiconductor substrate;   a chip having a different thermal expansion rate from a thermal expansion rate of the semiconductor substrate; and   a connection part including a porous metal layer for connecting connection pads that are arranged on opposing principle surfaces of the semiconductor substrate and the chip.   
     
     
         2 . The electronic device according to  claim 1 , wherein a difference between the thermal expansion rates of the chip and the semiconductor substrate is 0.1 ppm/° C. or greater. 
     
     
         3 . The electronic device according to  claim 1 , wherein
 the chip is a semiconductor laser, and   the semiconductor substrate includes a drive circuit that drives the semiconductor laser.   
     
     
         4 . The electronic device according to  claim 1 , wherein
 the chip is a semiconductor laser, and   the semiconductor substrate includes a temperature sensor.   
     
     
         5 . The electronic device according to  claim 3 , wherein
 the semiconductor laser includes a plurality of light emitting elements two-dimensionally arrayed, each of which emits laser light, and   the light emitting elements each have an electrode serving as anode and an electrode serving as cathode provided on a same plane.   
     
     
         6 . The electronic device according to  claim 5 , wherein
 the semiconductor substrate includes a switch, and   the switch is connected with the electrode serving as anode or the electrode serving as cathode.   
     
     
         7 . The electronic device according to  claim 6 , wherein
 the switch is connected with a corresponding group of the light emitting elements, and   the light emitting elements are subjected to light emission control for the corresponding group.   
     
     
         8 . The electronic device according to  claim 6 , wherein
 a plurality of the switches are connected with the respective light emitting elements, and   the light emitting elements are subjected to light emission control individually.   
     
     
         9 . The electronic device according to  claim 6 , wherein each of the electrodes serving as anode or each of the electrodes serving as cathode and each of the switches are connected with the connection part. 
     
     
         10 . The electronic device according to  claim 5 , wherein the light emitting elements are formed on a common substrate. 
     
     
         11 . The electronic device according to  claim 5 , wherein the light emitting elements have a vertical cavity surface emitting laser (VCSEL) structure. 
     
     
         12 . The electronic device according to  claim 1 , wherein insulating resin is filled between the semiconductor substrate and the chip and between the connection parts. 
     
     
         13 . The electronic device according to  claim 1 , wherein the porous metal layer includes a metal particle with a particle diameter of 0.005 μm to 1.0 μm. 
     
     
         14 . The electronic device according to  claim 1 , wherein
 the connection part includes a metal film having a same component as a component of the porous metal layer at least between the porous metal layer and the connection pad on the semiconductor substrate side or between the porous metal layer and the connection pad on the chip side.   
     
     
         15 . The electronic device according to  claim 14 , wherein the metal film is formed such that a ratio of a film thickness to a thickness of the connection part in a direction perpendicular to the principle surface is set to be 10% or smaller. 
     
     
         16 . The electronic device according to  claim 15 , wherein the metal film is formed such that the ratio of the film thickness to the thickness of the connection part in the direction perpendicular to the principle surface is set to be less than 5%. 
     
     
         17 . The electronic device according to  claim 14 , wherein the metal film is formed such that a ratio of a film thickness to a half of a thickness of the connection part in a direction perpendicular to the principle surface is set to be 10% or smaller. 
     
     
         18 . The electronic device according to  claim 17 , wherein the metal film is formed such that the ratio of the film thickness to a half of the thickness of the connection part in the direction perpendicular to the principle surface is set to be less than 5%. 
     
     
         19 . The electronic device according to  claim 1 , wherein a height ratio between the porous metal layer and the connection part in the direction perpendicular to the principle surface is larger than 90%. 
     
     
         20 . An electronic device, comprising:
 a semiconductor substrate; and   a bump including a metal film and a porous metal layer that are sequentially deposited on a surfaces of a connection pad that is arranged on a principle surface of the semiconductor substrate, wherein   the metal film is formed such that a ratio of a film thickness to a thickness of the bump in a direction perpendicular to the principle surface is set to be 10% or smaller.   
     
     
         21 . The electronic device according to  claim 20 , wherein
 the semiconductor substrate includes a drive circuit that drives the semiconductor laser mounted on the semiconductor substrate by flip chip mounting, and   the drive circuit controls a plurality of light emitting elements included in the semiconductor laser in an independent manner by controlling switches correspondingly connecting the light emitting elements and a current supply source.   
     
     
         22 . An electronic device comprising:
 a chip and   a bump including a metal film and a porous metal layer that are sequentially deposited on a surfaces of a connection pad that is arranged on a principle surface of the chip, wherein   the metal film is formed such that a ratio of a film thickness to a thickness of the bump in a direction perpendicular to the principle surface is set to be 10% or smaller.   
     
     
         23 . The electronic device according to  claim 22 , wherein
 the chip is a semiconductor laser,   the semiconductor laser includes a plurality of light emitting elements two-dimensionally arrayed, each of which emits laser light, and   the light emitting elements each have an electrode serving as anode and an electrode serving as cathode provided on a same plane.