Semiconductor device and automotive AC generator

Abstract

A semiconductor device includes a semiconductor element, a support member bonded to a first surface of the semiconductor element with a first bonding material, and a lead electrode bonded to a second surface of the semiconductor element supported on the support member with a second bonding material. Respective connecting parts of the support member and the lead electrode are Ni-plated and each of the first and the second bonding material is a Sn solder having a Cu 6 Sn 5 content greater than a eutectic content.

1 . A semiconductor device comprising: a semiconductor element; a support member bonded to a first surface of the semiconductor element with a first bonding material; and a lead electrode bonded to a second surface of the semiconductor element supported on the support member with a second bonding material; 
 wherein respective connecting parts of the support member and the lead electrode are Ni-plated and each of the first and the second bonding material is a Sn solder having a Cu 6 Sn 5  content greater than a eutectic content.    
     
     
         2 . The semiconductor device according to  claim 1 , wherein each of the first and the second bonding material is a Sn solder containing Cu 6 Sn 5  at temperatures between a room-temperature and 200° C.  
     
     
         3 . A semiconductor device comprising: a semiconductor element; a support member bonded to a first surface of the semiconductor element with a first bonding member; and a lead electrode bonded to a second surface of the semiconductor element supported on the support member with a second bonding member; 
 wherein a plated Ni layer and a Cu—Sn compound layer are formed in each of an interface between the support member and the first bonding member and an interface between the first bonding member and the semiconductor elements and a plated Ni layer and a Cu—Sn compound layer are formed in each of an interface between the lead electrode and the second bonding member and an interface between the second bonding member and the semiconductor element.    
     
     
         4 . The semiconductor device according to  claim 1 , wherein a buffer layer of a buffer material for absorbing a thermal expansion difference between the support member and the semiconductor element is formed between the support member and the semiconductor element.  
     
     
         5 . The semiconductor device according to  claim 4 , wherein the buffer material is Al, Mg, Ag, Zn, Cu or Ni.  
     
     
         6 . The semiconductor device according to  claim 4 , wherein the buffer material is a Cu/Invar/Cu composite material, a Cu/Cu 2 O composite material, a Cu—Mo alloy, Ti, Mo or W.  
     
     
         7 . The semiconductor device according to  claim 1 , wherein the plated Ni layer is made of Ni, Ni—P or Ni—B.  
     
     
         8 . The semiconductor device according to  claim 7 , wherein at least one of a plated Au layer, a plated Ag layer and a plated Pd layer is formed on the plated Ni layer.  
     
     
         9 . The semiconductor device according to  claim 1 , wherein the Cu—Sn compound is Cu 6 Sn 5 .  
     
     
         10 . The semiconductor device according to  claim 1 , wherein the bonding material is a foil, a paste or a wire.  
     
     
         11 . An automotive ac generator provided with the semiconductor device according to  claim 1 .  
     
     
         12 . A semiconductor device comprising: a substrate; and a semiconductor element bonded to the substrate with a bonding member; 
 wherein a plated Ni layer and a Cu—Sn compound layer are formed in each of an interface between the substrate and the bonding member and an interface between the bonding member and the semiconductor element.    
     
     
         13 . A semiconductor device comprising: a substrate; and a semiconductor element bonded to the substrate with a bonding material; 
 wherein plated Ni layers are formed on a connecting surface of the substrate and a connecting surface of the semiconductor element, respectively, the bonding material is a Sn solder of a composition having a Cu 6 Sn 5  content greater than a eutectic content.    
     
     
         14 . The semiconductor device according to  claim 13 , wherein the Cu—Sn compound is Cu 6 Sn 5 .  
     
     
         15 . The semiconductor device according to  claim 13 , wherein the bonding material is a foil, a paste or a wire.