High Temperature Lead-Free Attach Reliability

The increasing demand for electronics capable of operating at temperatures above the traditional 125°C limit is driving major research efforts. Wide band gap semiconductors have been demonstrated to operate at temperatures up to 500°C, but packaging is still a major hurdle to product development. Recent regulations, such as RoHS and WEEE, increase the complexity of the packaging task as they prohibit the use of toxic materials in electronic products; lead being a major concern due to its widespread use in solder attach. In this investigation, a series of Pb-free die attach technologies have been identified as possible alternatives to Pb-based materials for high temperature applications. This paper describes the fabrication sequence used to create attachments with these materials and their resultant microstructure. The long term reliability is also determined by accelerated thermal cycling and physics-of-failure modeling.