RF MEMS Switch with Wafer Level Package Utilizing Frit Glass Bonding

This paper reports experimental results of RF characteristics up to 20 GHz of a RF MEMS switch applied with wafer level packaging. A glass wafer is used as a package substrate on which frit glass is printed as material to seal the MEMS devices. The package wafer is bonded to a device wafer, which consists of actuators and base substrates. The actuators are made of single crystal silicon that has less residual stress. The base substrate has through holes formed by sand blast. The switch achieves a low insertion loss of 1.3 dB and a high isolation of 19 dB up to 20 GHz, and can be mounted on to a circuit board with bumps, like flip chip. The wafer level packaging with low cost and high reliability will transfer RF MEMS devices, which has superior high frequency characteristics even in quasi-millimeter wave band, to the practical use.