Composite Aluminum-Copper Ribbon Bonding – Heel Reliability

摘要

Ultrasonic bonding is a very versatile joining technique with a wide applicability beyond microelectronic packaging. Large diameter round Aluminum wire is widely used because of its flexibility and its robust bond process capability on a variety of surfaces. Aluminum ribbon bonding is an extension of large Aluminum wire bonding. Although the rectangular cross-section of a ribbon offers additional benefits in many applications, further improvements to fulfill anticipated future performance, functionality and reliability requirements motivate the evaluation of different ribbon materials. rnThis paper introduces bonding of composite ribbon, specifically Aluminum-clad Copper ribbon. First, the heel reliability of such material was investigated and compared to standard Aluminum ribbon, large Aluminum wire, and large Copper wire. rnThe experiments indicate that in a given configuration, Aluminum-clad Copper ribbon enables significantly higher numbers of cycles to failure, on the order of a factor one hundred compared to standard round Aluminum wire, and a factor ten compared to standard Aluminum ribbon. At the same time, for high current applications, Aluminum-clad Copper ribbon can also replace several large Aluminum wires, consequently enabling a substantial reduction in manufacturing cost.