Electrical barrier layers

Abstract

An electrical connection structure includes a variable-composition nickel alloy layer with a minor constituent selected from a group consisting of boron, carbon, and tungsten, wherein at least over a portion of a conductive substrate, the concentration of the minor constituent varies throughout the variable-composition nickel alloy layer in a direction from the bottom surface of the variable-composition nickel alloy layer to the top surface of the variable-composition nickel alloy layer.

1 . A device comprising an electrical connection structure comprising:
 a conductive substrate;   a variable-composition nickel alloy layer above the conductive substrate and in electrical contact with the conductive substrate, the variable-composition nickel alloy layer having a bottom surface overlying and physically contacting a first surface of a first material, and having a top surface underlying and physically contacting a second surface of a second material, wherein the first and second materials do not have nickel as a major constituent, the variable-composition nickel alloy layer comprising a minor constituent selected from a group consisting of boron, carbon, and tungsten, wherein at least over a portion of the conductive substrate, the concentration of the minor constituent varies throughout the variable-composition nickel alloy layer in a direction from the bottom surface of the variable-composition nickel alloy layer to the top surface of the variable-composition nickel alloy layer; and   a conductive layer disposed above the variable-composition nickel alloy layer and in electrical contact with the variable-composition nickel alloy layer and the conductive substrate.   
     
     
         2 . The device of  claim 1  wherein the first surface is a top surface of the conductive substrate. 
     
     
         3 . The device of  claim 1  wherein the first material comprises at least one of gold, silver, palladium, platinum, copper. 
     
     
         4 . The device of  claim 1  wherein the second surface is a bottom surface of the conductive layer. 
     
     
         5 . The device of  claim 1  wherein the second material comprises at least one of gold, silver, palladium, platinum, copper. 
     
     
         6 . The device of  claim 1  wherein the conductive layer is solder. 
     
     
         7 . The device of  claim 1  wherein at least over said portion of the conductive substrate, the concentration of the minor constituent in the variable-composition nickel alloy layer is at most 10% by weight. 
     
     
         8 . The device of  claim 1  wherein at least over said portion of the conductive substrate, the nickel concentration in the variable-composition nickel alloy layer is at least 80% by weight. 
     
     
         9 . The device of  claim 1  wherein the minor constituent is boron. 
     
     
         10 . The device of  claim 1  wherein the minor constituent is carbon. 
     
     
         11 . The device of  claim 1  wherein the minor constituent is tungsten. 
     
     
         12 . The device of  claim 1  wherein a top surface of the conductive layer is available for being bonded to a wire external to the device. 
     
     
         13 . The device of  claim 1  further comprising a wire bonded to a top surface of the conductive layer. 
     
     
         14 . A device comprising an electrical connection structure comprising:
 a conductive substrate whose top surface does not include nickel as a major constituent;   a variable-composition nickel alloy layer on the conductive substrate, the variable-composition nickel alloy layer comprising a minor constituent selected from a group consisting of boron, carbon, and tungsten, wherein at least over a portion of the conductive substrate, the concentration of the minor constituent varies throughout the variable-composition nickel alloy layer in a direction from the bottom surface of the variable-composition nickel alloy layer to the top surface of the variable-composition nickel alloy layer; and   a conductive layer on the variable-composition nickel alloy layer, the conductive layer aving a bottom surface which does not include nickel as a major constituent.   
     
     
         15 . The device of  claim 14  wherein the conductive substrate is gold, silver, palladium, platinum, or copper. 
     
     
         16 . The device of  claim 14  wherein the conductive layer is gold, silver, palladium, platinum, or copper. 
     
     
         18 . The device of  claim 14  wherein the conductive layer is solder. 
     
     
         19 . The device of  claim 14  wherein the minor constituent is boron. 
     
     
         20 . The device of  claim 14  wherein the or constituent is carbon or tungsten.