A micro-model for elasto-plastic adhesive–contact in micro-switches: Application to cyclic loading

Abstract

Stiction is a major failure mode in micro-electromechanical systems. In previous works, a statistical rough surfaces interaction model, for which only elastic adhesive contact has been considered, was developed for multiscale analyzes.However, during the impact between rough surfaces, plastic deformations of asperities cannot always be neglected. In the present work, the adhesion between rough surfaces is studied considering the elasto-plastic deformations of the asperities, and a model predicting the resulting micro adhesive-contact forces is derived.For illustration purpose, an electrostatic-structural analysis is performed on a micro-switch. To determine the degree of plasticity involved, the impact energy of the movable electrode at pull-in is estimated. Thus the maximal adhesive force evolution during cyclic loading is predicted using the developed model.

A computational stochastic multiscale methodology for MEMS structures involving adhesive contact

“…(6) and the corresponding PSD function can be obtained using Eq. (8). In addition to this indirect method, the PSD function can be estimated directly from the measurements of the surface height as follows…”

“…For the cases when irreversible deformations become non-negligible [52], the applied asperity contact models, Hertz and Maugis models, should be replaced, e.g. by the ones developed by L. Kogut and I. Etsion [53,54], or by the one developed by L. Wu et al [8] in the case of cyclic load.…”

“…Ng integral points as 8) where T −1 is the approximation of inverse Rosenblatt transformation T −1 for which the probability density function and cumulative distribution functions are evaluated using multivariate kernel density estimation, Eq. (B.1), and {ξ and relMISE PC are also evaluated using the Gauss quadrature rule.…”

“…One of the common failures in microelectromechanical systems (MEMS) is stiction [1,2,3,4,5,6,7,8], in which two micro surfaces permanently adhere together, e.g. the stiction failure of micro cantilever beams illustrated in Fig.…”

The Effect on Switching Lifetime of Chromium Adhesion Layers in Gold-Coated Electrical Contacts under Cold and Hot Switching Conditions

“…We propose that the welds exert a peeling force between the contacts during opening, lifting the film from the substrate [15]. After a number of cycles it is believed that the surface asperities deform (flatten), effectively increasing the radius of the asperities [16]. The strength of the welds increases as the area increases, until the force from the welded contact spots can overcome the adhesion between the gold film and the substrate [16].…”