A batch-mode assembly and packaging technology for 3-axis tri-fold inertial measurement units

This paper reports a batch-mode generic 3-D precision assembly and wafer-level packaging technology for 3-axis tri-fold inertial measurement units (IMUs) using silicon mounting jig wafers with embedded vacuum channels. This approach allows use of optimized single-axis IMUs without manufacturing and structural constraints of forming 3-axis in a chip, and improving the overall yield by testing the chips prior to 3-D assembly. The 3-D chip assembly is performed by a controlled sequence of vacuum through the channels and bottom access holes, ambient pressurization, and raise of temperature to form permanent rigid tri-fold bond to the jig wafer.