tailieunhanh - Modeling of failure mechanisms for optimized mems cad

Modeling of failure mechanisms for optimized mems cad : design , fabrication and chatacterization of in situ test benches | MODELING OF FAILURE MECHANISMS FOR OPTIMIZED MEMS CAD DESIGN FABRICATION AND CHARACTERIZATION OF IN SITU TEST BENCHES Olivier Millet Vincent Agachea Bernard Legrand Dominique Collardb and Lionel Buchaillot Institut d Electronique de Micro-électronique et de Nanotechnologie IEMN3 and Center for International Research on MicroMechatronics CIRMMb IEMN. UMR CNRS 8520. Avenue Poincare. Cité scientifique. 59652 Villeneuve d Ascq France Tel. -1-0033 3 20 19 78 38 Fax 0033 3 20 19 78 84 E-mail ABSTRACT PRINCIPLE This work considers the reliability of surface microfabricated structures and particularly the dynamic response of structural layers during operations in order to develop a statistical modelling of failure mechanisms for micro-actuator. In situ test benches have been designed and fabricated allowing to applied elementary solicitations traction bending and torsion to representative samples. Gold in situ doped pdlysilicon and polysilicon doped by diffusion are used as structural layers. These devices are useful to study the fatigue phenomenon. Characterization and fatigue tests have been performed in a vacuum chamber under different environmental and stimuli conditions. Moreover a theoretical analysis using Finite Elements Method has been achieved. INTRODUCTION The next generation of CAD programs for MEMS will have to ensure a precise evaluation of the system lifetime by anticipating the failure mechanisms. The principle is to develop a statistical modeling indicating the probability that a failure mechanism occurs via the determination of statistical rules describing probability of failures generated in each elementary structure beam etc. during the operation of the whole system 1 2 3 . Then this work aims at understanding the fatigue phenomenon for elementary structures and to describe it statistically according to the design the use and the environment of the microsystem. Our activity deals with the design and the realization of .