Stiction Failure in Microswitches Due to Elasto-Plastic Adhesive Contacts
Undesirable stiction, which results from the contact between surfaces, is a major failure mode in micro-switches. Indeed the adhesive forces can become so important that the two surfaces remain permanently glued, limiting the life-time of the MEMS. This is especially true when the contact happens between surfaces where elasto-plastic asperities deform permanently until the surfaces reach plastic accommodation, increasing the surface forces. To predict this behavior, a micro adhesive-contact model is developed, which accounts for the surfaces topography evolutions during elasto-plastic contacts. This model can be used at a higher scale to study the MEMS behavior, and thus its life-time. The MEMS devices studied here are assumed to work in a dry environment. In these operating conditions only the Van der Waals forces have to be considered for adhesion. 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 is predicted using the developed model.
- 2.Do C, Hill M, Lishchynska M, Cychowski M, Delaney K (2011) Modeling, simulation and validation of the dynamic performance of a single-pole single-throw RF-MEMS contact switch. In: 2011 12th international conference on thermal, mechanical and multi-physics simulation, and experiments in microelectronics and microsystems (EuroSimE), Linz, Austria, April 2011, pp 1–6Google Scholar
- 4.Wu L, Rochus V, Noels L, Golinval J-C (2009) Influence of adhesive rough surface contact on microswitches. J Appl Phys 106(11):113502-1–113502-10Google Scholar
- 14.Wu L, Golinval J-C, Noels L. A micro model for elasto-plastic adhesive-contact in micro-switches. Tribol Int (submitted)Google Scholar
- 18.Kadin Y, Kligerman Y, Etsion I (2007) Cyclic loading of an elasticplastic adhesive spherical microcontact. J Appl Phys 104(7):073522-1–073522-8Google Scholar