Electronic Device with Multi-Layer Contact

Abstract

An electric device with a multi-layer contact is disclosed. In an embodiment, the electronic device includes a carrier, a semiconductor substrate attached to the carrier, and a layer system disposed between the semiconductor substrate and the carrier. The layer system includes an electrical contact layer disposed on the semiconductor substrate. A functional layer is disposed on the electrical contact layer. An adhesion layer is disposed on the functional layer. A solder layer is disposed between the adhesion layer and the carrier.

What is claimed is: 
     
         1 . An electronic device, comprising:
 a carrier having a metallic surface;   a semiconductor substrate attached to the carrier; and   a layer system disposed between the semiconductor substrate and the carrier, the layer system comprising:
 an electrical contact layer disposed on the semiconductor substrate; 
 a functional layer disposed on the electrical contact layer; 
 an adhesion layer disposed on the functional layer; and 
 a solder layer disposed between the adhesion layer and the carrier. 
   
     
     
         2 . The electronic device according to  claim 1 , wherein the semiconductor substrate comprises a silicon-based semiconductor material. 
     
     
         3 . The electronic device according to  claim 1 , wherein the electrical contact layer comprises a single element layer of Al, Ti, Ag, or Cr, or an alloy containing one or more of these elements. 
     
     
         4 . The electronic device according to  claim 1 , wherein the functional layer comprises a barrier layer. 
     
     
         5 . The electronic device according to  claim 1 , wherein the functional layer comprises Ti, TiW, or W, or alloys containing these materials. 
     
     
         6 . The electronic device according to  claim 1 , wherein the adhesion layer comprises a single element layer of Cu, Au, Ag, Pt, or Ni, or an alloy containing one or more of these elements. 
     
     
         7 . The electronic device according to  claim 1 , wherein the solder layer comprises a single element layer of Sn, Zn, In, Ga, Bi, or Cd, or an alloy containing one or more these elements. 
     
     
         8 . The electronic device according to  claim 7 , wherein the solder layer comprises an alloy of one or more of Sn, Zn, In, Ga, Bi, or Cd and also comprises AuSn, SnAg, CuSn, or CuSnAg. 
     
     
         9 . The electronic device according to  claim 1 , wherein the carrier comprises Cu, Ni, or Fe, or an alloy containing one or more of these elements. 
     
     
         10 . The electronic device according to  claim 1 , wherein a surface of the carrier is coated with one or more metal layers. 
     
     
         11 . The electronic device according to  claim 1 , wherein an uppermost metal layer comprises Au, Ag, Cu, Pd, or Pt, or an alloy of one or more of these elements. 
     
     
         12 . The electronic device according to  claim 1 , wherein intermetallic phases are formed between the adhesion layer and the solder layer. 
     
     
         13 . The electronic device according to  claim 1 , wherein intermetallic phases are formed between the carrier and the solder layer or between a metal layer disposed on the carrier and the solder layer. 
     
     
         14 . The electronic device according to  claim 1 , wherein the adhesion layer and a carrier surface or a surface of a metal layer coated on the carrier surface are formed of the same base material. 
     
     
         15 . The electronic device according to  claim 14 , wherein the base material comprises Cu, Ag, NiV, Ni, or NiNiP. 
     
     
         16 . The electronic device according to  claim 1 , wherein the carrier comprises a leadframe. 
     
     
         17 . The electronic device according to  claim 1 , wherein the layer system is free of Au. 
     
     
         18 . A method for fabricating an electronic device, the method comprising:
 providing a semiconductor substrate;   depositing an electrical contact layer onto the semiconductor substrate;   depositing a functional layer onto the electrical contact layer;   depositing an adhesion layer onto the functional layer;   depositing a solder layer onto the adhesion layer;   depositing a protective layer onto the solder layer; and   attaching the semiconductor substrate onto a carrier.   
     
     
         19 . The method according to  claim 18 , wherein depositing one or more of the electrical contact layer, the functional layer, the adhesion layer, the solder layer, and the protective layer comprises depositing by physical vapor deposition. 
     
     
         20 . The method according to  claim 18 , wherein
 the electrical contact layer comprises an Al or Ti layer,   the functional layer comprises a Ti, TiW or W layer,   the adhesion layer comprises a Cu or Ag layer,   the solder layer comprises an Sn layer, and   the protective layer comprises an Ag or Au layer.