New methodology for enhancing electrical conductivity and strength of copper alloy using combined structure

Copper alloy has been used as interconnection materials for various electronic applications due to their intrinsic properties of high conductivity and pertinent strength. The required properties of copper alloy have been intensified to let higher performance of final products possible. That is to say, the copper alloy featuring both high conductivity and high strength has recently been needed. However, the both properties are generally known as an inverse relationship each other. We suggested new methodology for enhancing electrical conductivity and strength of copper alloy using the combined structure, which consists of a strengthened bulk with discretely thin-layered copper embedded by silver. It was expected that the combined structure consisting of copper and silver would show higher performance than the conventional copper when applied into the high frequency products, because the silver was embedded on the surface of copper. The embedded layer, conduction path, having a 100um width was formed by photo resist coating, UV exposure/development, chemical etching and plating, which is similar to the conventional semiconductor process. From these works, copper alloy with the 40%IACS conductivity and 600MPa strength showed the improved properties of 60%IACS and 600MPa, respectively, which was 50% higher conductivity than the conventional copper alloy and was similar strength. The simultaneous properties of conductivity and copper alloy were possibly obtained by the combined structure.