Techniques for improving bond pad performance
Techniques for bond pad fabrication are provided. In one aspect, a method of forming a bond pad comprises the following steps. At least one alloying element is selectively introduced to at least a portion of at least one surface of the bond pad. The at least one alloying element is diffused into at least a portion of the bond pad through one or more thermal cycles. The at least one alloying element may be selectively introduced to the bond pad by depositing an alloying element layer comprising the at least one alloying element onto the bond pad and patterning and etching at least a portion of the layer.
1 . A method of forming a bond pad, the method comprising the steps of:
selectively introducing at least one alloying element to at least a portion of at least one surface of the bond pad; and
diffusing the at least one alloying element into at least a portion of the bond pad through one or more thermal cycles.
2 . The method of claim 1 , wherein the step of selectively introducing the at least one alloying element to the bond pad further comprises the steps of:
depositing an alloying element layer comprising the at least one alloying element onto the bond pad;
patterning at least a portion of the deposited alloying element layer; and
etching at least a portion of the patterned alloying element layer.
3 . The method of claim 1 , wherein the at least one alloying element is diffused into a near-surface region of the bond pad.
4 . The method of claim 1 , wherein the at least one alloying element is diffused into a near-surface region of the bond pad which comprises up to about a two micrometer region from a surface of the bond pad.
5 . The method of claim 1 , wherein the at least one alloying element is diffused into a near-surface region of the bond pad which comprises up to about a 1.2 micrometer region from a surface of the bond pad.
6 . The method of claim 1 , wherein the at least one alloying element comprises one or more of copper, nickel, cobalt, palladium, silver and gadolinium.
7 . The method of claim 1 , wherein the bond pad comprises one or more of aluminum, gold and nickel.
8 . The method of claim 2 , wherein the an alloying element layer is deposited using one or more of vacuum evaporation, sputtering, electrolytic plating, electroless plating, metallo-organic vapor deposition, atomic layer deposition and thin film deposition techniques.
9 . The method of claim 2 , wherein the patterning step comprises use of one or more of a photosensitive material, a photoimaging polymer, a photoresist, a photosensitive polyimide and a dry film resist.
10 . The method of claim 2 , wherein the etching step comprises use of a wet chemical etchant.
11 . The method of claim 2 , wherein the etching step comprises use of reverse current electrolytic techniques.
12 . The method of claim 2 , wherein the etching step comprises use of chemical-mechanical polishing techniques.
13 . The method of claim 1 , wherein the at least one alloying element is diffused into the at least a portion of the bond pad through a plurality of thermal cycles.
14 . A bond pad comprising:
at least one alloying element present predominately in a near-surface region of the bond pad.
15 . The bond pad of claim 14 , comprising one or more of aluminum, gold and nickel.
16 . The bond pad of claim 14 , wherein the at least one alloying element comprises one or more of copper, nickel, cobalt, palladium, silver and gadolinium.
17 . The bond pad of claim 14 , wherein the at least one alloying element comprises an aluminum/nickel/gadolinium alloy.
18 . The bond pad of claim 14 , wherein the near-surface region comprises up to about a two micrometer region from a surface of the bond pad.
19 . The bond pad of claim 14 , wherein the near-surface region comprises up to about a 1.2 micrometer region from a surface of the bond pad.
20 . The bond pad of claim 14 , wherein the near-surface region comprises greater than or equal to about 90 percent of the at least one alloying element present in the bond pad.
21 . The bond pad of claim 14 , wherein the near-surface region comprises greater than or equal to about 95 percent of the at least one alloying element present in the bond pad.