Electro micro-metrology

Electro Micro-Metrology (EMM) is a novel methodology for precision metrology, sensing, and actuation at the micro- and nano-scale. We present novel methods which conform well at the micro- and nano-scale by utilizing the beneficial aspects of the scale such as the precise sensing and actuation capabilities of micro electromechanical systems. Moreover, all measurements are based on the actual performance of the device. This is important because it is the performance of the device that system designers and users care about most. We present techniques that differ from conventional techniques in practicality and that none of the geometric, dynamic, or material property values of the fabricated devices are presumed. Only on- or off-chip, capacitively-based measurements are required. In this dissertation we describe the methods and application of Electro Micro-Metrology. We derive analytical extraction formulas and we analyze the precision and limits of application. The methods cover the extraction of over two dozen fundamental properties. The geometric, dynamic, and material properties are classified as follows. Geometric properties include the extraction of beam widths, beam lengths, gap spacing, etch hole size, plate area, sidewall angle, and layer thickness. Dynamic properties include comb drive force, minimum gap closing voltage, fringing field factor, displacement, system stiffness, displacement resonance, velocity resonance, natural frequency, damping factor, time constant, mass, and damping. Material properties include system Young's modulus, quality factor, beam stiffness, material Young's modulus, Poisson's ratio, shear modulus, residual strain, residual stress, and comb drive asymmetry. We also show that the errors due to both our modeling assumptions and microfabrication assumptions are smaller than the errors due to electrical measurands, as long as the measurements performed on the test structure are within their prescribed operating range. We examine fabrication issues such as deposition, proximity, lithography, etchants, and residual stress. We examine nonideal modeling issues such as nonlinear dynamics, electrostatic fields, the capacitance and stiffness of coarse sidewalls, and deflection-induced moments. Finally, we conclude by summarizing our results and examining future research directions and applications of Electro Micro-Metrology to measure more complex phenomena and its application to computer aided engineering and design. (Abstract shortened by UMI.)