Die Attach Material Choice for MEMS Cavity Packages

MEMS (Micro-Electromechanical Systems) motion sensors are, by their very nature as mechanical movement sensors, sensitive to the stress caused by any material in contact with the sensor itself. Standard MEMS motion sensors commonly use Land Grid Array (LGA) packages with die attach and resin mould [1], [2] due to best tradeoff reason between cost and performance, but this approach introduces stresses from both moulding compound and Die Attach Film (DAF) material [3]. For higher performance devices the use of ceramic cavity packages [4] is preferable, as the DAF is the only material in contact with the sensor. In this paper we will illustrate the effects of the interaction between the die attach and the sensor performances, further showing the benefits resulting from the choice of a low Young's modulus DAF.