Development of a Sensitive Element of a Micromechanical Accelerometer

• Published in: Russian microelectronics Vol. 51; no. 7; pp. 606 - 610
• Main Authors: Kochurina, E. S., Anchutin, S. A., Kalugin, V. V., Zaryankin, N. M., Timoshenkov, A. S., Dernov, I. S.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 2022; Springer Nature B.V
• Subjects: Acceleration; Accelerometers; Capacitance; Chemical etching; Crystallography; Electrical Engineering; Engineering; Finite element method; Manufacturing; Misalignment; Modal analysis; Power consumption; Silicon; anisotropic liquid etching; MEMS; micromechanical accelerometer; sensing element; experimental research results
• ISSN: 1063-7397; 1608-3415
• DOI: 10.1134/S1063739722070162

Micromechanical accelerometers (MMAs) are widely used in industry and in robotechnics, as they are characterized by low power consumption, small size and weight, and low cost in serial production. Therefore, the development and research of MMAs is an urgent task. In this study, when modeling the sensitive element (SE) of MMAs, a software system of finite element analysis is used, which allows for static and modal analysis. The results of the preliminary calculations of the MMA scale factor, which can be collected based on the developed SE and sigma-delta transducer, are presented. The technological process of manufacturing the SE of MMAs using anisotropic liquid chemical etching of silicon to obtain different profiles of the corresponding crystallographic planes is described. The results of studying the effect of technological errors on the geometrical dimensions of the SE are presented: the dependence of the value of the lateral underetching of silicon on the accuracy of the angular alignment of the mask with the crystallographic axis of the plate (100) is revealed. The simulation performed confirms the operability of the design, the calculations show a change in the scale factor in the temperature range from –60 to +125°C, nominal capacitance, and capacitance with a change in linear acceleration in the range of ±60 g . In manufacturing SEs based on the the studies performed, it is possible to obtain a lateral underetching of up to 5 μm at an anisotropic liquid chemical etching depth of 250 μm for KDB-0.01 wafers with an orientation tolerance of ±30 arc minutes or with a misorientation of the same value allowed during exposure.