Ribbon bonding in an electronic package

Abstract

A flexible conductive ribbon is ultrasonically bonded to the surface of a die and terminals from a lead frame of a package. Multiple ribbons and/or multiple bonded areas provide various benefits, such as high current capability, reduced spreading resistance, reliable bonds due to large contact areas, lower cost and higher throughput due to less areas to bond and test.

1 . An electronic package, comprising: 
 an electronic device having a conductive upper surface;    a conductive terminal external to the electronic device; and    a conductive ribbon ultrasonically bonded to a first portion of the conductive upper surface and bonded to the conductive terminal, wherein the conductive ribbon comprises a first layer contacting the conductive upper surface and a second layer overlying the first layer.    
     
     
         2 . The electronic package of  claim 1 , wherein the first layer is aluminum and the second layer is copper.  
     
     
         3 . The electronic package of  claim 2 , wherein the first layer is thinner than the second layer.  
     
     
         4 . The electronic package of  claim 1 , wherein the conductive ribbon further comprises a third layer overlying the second layer.  
     
     
         5 . The electronic package of  claim 1 , wherein the first layer and the conductive upper surface comprise the same material.  
     
     
         6 . The electronic package of  claim 1 , wherein the ribbon has a rectangular cross section.  
     
     
         7 . An electronic package, comprising: 
 an electronic device having a conductive upper surface;    a conductive terminal external to the electronic device; and    a conductive ribbon ultrasonically bonded to a first portion of the conductive upper surface and bonded to the conductive terminal, wherein the conductive ribbon comprises a first layer contacting the conductive upper surface and a second layer overlying the first layer, and wherein the first layer is aluminum and the second layer is copper.    
     
     
         8 . A conductive ribbon for ultrasonically bonding a first portion of a conductive upper surface to a conductive terminal, the ribbon comprising: 
 an aluminum layer of rectangular cross section, wherein the aluminum layer contacts the conductive upper surface; and    a copper layer of rectangular cross section formed over the aluminum layer.    
     
     
         9 . The conductive ribbon of  claim 8 , further comprising a coupling layer formed over the copper layer.  
     
     
         10 . The conductive ribbon of  claim 8 , wherein the aluminum layer is thinner than the copper layer.  
     
     
         11 . The conductive ribbon of  claim 9 , wherein the coupling layer is aluminum.