Intrinsic stress of eutectic Au/Sn die attachment and effect on mode-matched MEMS gyroscopes

Author

Simon, Brenton R. ; Sharma, Gitika ; Zotov, Sergei A. ; Trusov, Alexander A. ; Shkel, Andrei M.

Author_Institution

Microsyst. Lab., Univ. of California, Irvine, Irvine, CA, USA

fYear

2014

fDate

25-26 Feb. 2014

Firstpage

1

Lastpage

4

Abstract

We report on the intrinsic stress imparted to MEMS gyroscopes and the effects on frequency mismatch due to high-temperature die attachment processes, such as eutectic Au/Sn solder. The resonant frequencies of a number of symmetric MEMS gyroscopes are characterized before and after die attachment, along with X-ray imaging to observe the random solder reflow that occurred during attachment. Frequency shift is observed and compared to the die attachment area, with an 87 percent correlation to the length of the solder reflow. A model of the phenomena is presented with less than 0.1 percent agreement to the experimental results, indicating an optimal die attachment for the minimization of stress-induced frequency changes.

Keywords

X-ray imaging; eutectic alloys; gold alloys; gyroscopes; internal stresses; microassembling; microsensors; solders; tin alloys; Au-Sn; X-ray imaging; eutectic Au/Sn die attachment; frequency mismatch; frequency shift; high-temperature die attachment processes; intrinsic stress; mode-matched MEMS gyroscopes; random solder reflow; resonant frequencies; Gyroscopes; Micromechanical devices; Packaging; Resonant frequency; Silicon; Stress; Temperature sensors;

fLanguage

English

Publisher

ieee

Conference_Titel

Inertial Sensors and Systems (ISISS), 2014 International Symposium on

Conference_Location

Laguna Beach, CA

Type

conf

DOI

10.1109/ISISS.2014.6782529

Filename

6782529