Solder alloy and a semiconductor device using the solder alloy

Abstract

A solder alloy contains from 3 to 5 wt % of antimony (Sb), not more than 0.2 wt % of germanium (Ge), and the balance of tin (Sn). In a semiconductor device, the solder alloy can be used to join a semiconductor chip and a conductor pattern on the front surface of an insulative substrate, a conductor pattern on the back surface of the insulative substrate and a heat sink plate, and the semiconductor chip and a wiring conductor. The solder alloy exhibits excellent wettability and satisfactory bonding performance.

1 . A solder alloy comprising: 
 antimony in a range of from 3 to 5 wt %;    a trace amount of germanium; and    a balance of tin.    
     
     
         2 . The solder alloy according to  claim 1 , wherein the amount of germanium is from 0.01 to 0.2 wt %.  
     
     
         3 . The solder alloy according to  claim 1 , wherein the amount of germanium is not more than 0.2 wt %.  
     
     
         4 . A semiconductor device with a solder alloy, comprising: 
 an insulative substrate having conductor patterns on two surfaces thereof;    a semiconductor chip joined to the conductor pattern on a front surface of the insulative substrate; and    a heat sink plate joined to the conductor pattern on a back surface of the insulative substrate, wherein    the conductor pattern on the back surface of the insulative substrate and the heat sink plate are soldered with a solder alloy comprising antimony in a range of from 3 to 5 wt %, a trace amount of germanium, and a balance of tin.    
     
     
         5 . The semiconductor device with the solder alloy according to  claim 4 , wherein a back surface of the semiconductor chip and the conductor pattern on the front surface of the insulative substrate are soldered with a solder alloy comprising antimony in a range of from 3 to 5 wt %, a trace amount of germanium, and a balance of tin.  
     
     
         6 . The semiconductor device with the solder alloy according to  claim 4 , further comprising electrodes disposed on a front surface of the semiconductor chip, and conductors for wiring, 
 wherein the electrodes and the conductors for wiring are soldered with a solder alloy comprising antimony in a range of from 3 to 5 wt %, a trace amount of germanium, and a balance of tin.    
     
     
         7 . The semiconductor device with the solder alloy according to  claim 4 , wherein the amount of germanium is not more than 0.2 wt %.  
     
     
         8 . The semiconductor device with the solder alloy according to  claim 4 , wherein the insulative substrate is a ceramic substrate substantially composed of alumina, aluminum nitride, or silicon nitride, and has copper patterns on both surfaces of the substrate, and the heat sink plate is made of copper.