Wafer level vacuum packaged de-coupled vertical gyroscope by a new fabrication process

Abstract

A highly reliable, wafer level vacuum packaged and de-coupled vertical microgyroscope was developed. The de-coupled gyroscope which had four driving springs and two sensing springs was designed and fabricated. A new fabrication process which could realize a high aspect ratio and use a thick single crystalline silicon as a structure layer, was proposed. The vacuum environment for operating a vibratory gyroscope was accomplished with vacuum packaging at wafer level. The vacuum level of ambient pressure was about 150 mtorr. The resolution of the gyroscope was 0.013/spl deg//sec/Hz/sup 1/2/. The output nonlinearity was below 2% in /spl plusmn/100/spl deg//s full scale.