Authors: M. Maute, S. Kimmerle, J. Franz, J. Hauer, D. Schubert, H.-R. Krauss and D.P. Kern
Affilation: Robert Bosch GmbH, Germany
Pages: 406 - 409
Keywords: accelerometer, micromachining, parameter extraction, CV-characteristic
This paper presents a novel methodology for the extraction of process dependent geometrical parameters of surface micromachined sensors. This approach is based on the electrical measurement of static capacitance-voltage characteristics of the sensor element on wafer level. This extraction technique is demonstrated using a surface micromachined inertial accelerometer: a) The measurement of the capacitance-voltage characteristic (CV-characteristic) for lateral actuation of the suspended proofmass results in the extraction of a parameter related both to the thickness of the functional polysilicon layer and the lateral sidewall overetch due to the etch process of the polysilicon . b) For vertical actuation of the proofmass, measurements of CV-characteristics lead to an extracted parameter that is proportional to the sidewall difference angle of the beam cross-section.