Effects of Die Attachment Induced Stress on the Reliability of a Packaged MEMS Device

A microelectromechanical systems (MEMS) actuator was selected to study the effects of packaging induced stress on device reliability. In this work, MEMS devices were obtained and packaged using cyanate ester, 96.5/3.5 Sn/Ag, and 92.5/5/2.5 Pb/Sn/Ag die attachment materials. The die attachment materials were then cured or reflowed appropriately and cooled to room temperature which induced stress through the coefficient of thermal expansion mismatches between the silicon die and alumina package. In this work, a MEMS microengine developed at Sandia National Laboratories, which is a device that has been well studied, was selected as a test vehicle to understand the effects of various die attachment solders and related processes parameters on the ultimate functionality of the packaged MEMS microengine. Particularly, the operational lifetime of these devices was measured by testing these devices to failure. These lifetimes were then compared with baseline values to determine the effect of stress on these device...