A Static Analysis of Snap Back in the Cantilever with Mems Adhesion

Abstract

The "Snap back" problem of the micro-cantilever remains one of the dominant failure mechanisms in the Micro Electro-mechanical System (MEMS). By analyzing the Hamaker micro continuum medium and solid physics principle, the consistency model of Wigner-Seitz (W-S) continuum medium is presented. The gap revision coefficients of the body with the face-centered cubic structure are derived, which include the attractive force and the repulsive one. The adhesion model of the 500 m 1 m silicon micro-cantilever coated by Au is established. The micro-cantilever static relationship between the elastic force and the adhesion force is discussed. The reason of the microcantilever "snap back" problem, an instable balanced point, is discovered. Increasing the rigidity of the micro-cantilever, a method to avoid the micro-cantilever "snap back" to happen, is put forward, which improves MEMS structure design and enhances MEMS reliability.