Microelectronic materials, microfabrication processes, micromechanical structural configuration based stiffness evaluation in MEMS: A review

Abstract

Microsystem or micro-electro-mechanical system (MEMS) is a revolutionary enabling technology, that is responsible for many of the technological advancements over the past few decades. Many such microsystems consist of suspensions mostly in the form of microcantilevers which are intended to perform desired function by detecting the changes in cantilever bending or vibrational frequency. The bending or deflection of the cantilever beam critically depends upon the mechanical properties, like stiffness, which is contingent on the type of materials, fabrication processes, and structural configurations. This paper evaluates cantilever stiffness of different MEMS devices in relation to aforesaid aspects. Common microelectronic materials like silicon, silicon dioxide, silicon nitride, gold, polymers etc. were seen to provide stiffness ranging from 0.012 N/m to 319.74 N/m that is influenced by elastic modulus & density for a given design. Likewise, fabrication process was seen to affect stiffness through process temperature & residual stress effects for different materials. Also, the structural shape geometry was observed to influence the same due to modified cross-sectional areas and straight & folded spring configurations. In this review, light is shed on abovementioned parameters which are found to be crucial in designing efficient MEMS devices and structures. © 2022 Elsevier B.V.