Reliability analysis on wafer bonding process of MEMS circulator

MEMS circulator is a promising substitute of the traditional circulator to cascade RF modules and realize the miniaturization of RF micro system for radar and communication system. The silicon-based MEMS circulator is assembled with silicon chip, ferrite and magnetic steel. The silicon chips for
${6\ \text{mm} \times 6\ \text{mm}}$
Mems circulator were prepared by wafer bonding using Au-Au and Au-Sn as bonding material and signal interconnection with bonding area of
${8.55\ \text{mm}^{2}}$
. And the bonding behaviors of two different metal bonding processes were compared and analyzed in this paper. The results illustrated that the shear forces of both bonding methods were
$>$
21kg. F (the shear strength
$> \mathbf{24}$
MPa). In shear force test of process control monitor (PCM) cells with different bonding areas, the shear force of the chip was promoted with the increase of bonding area. The shear force is supposed to be
$> \mathbf{2}$
kg. F (the shear strength
$> {20}$
MPa) when the bonding area is
${> 1.00\ \text{mm}^{2}}$
. The insertion loss of the chips using both processes were less than 0.5 dB. It has been validated that both bonding methods are feasible and reliable for MEMS circulators.