Modelling and investigation of the silicon twin design 3D micro probe

Abstract

The 3D micro probe is based on a silicon boss-membrane with piezo-resistive transducers, which enable the measurement of the deflections of the probing pin and, simultaneously, the forces in all three dimensions. The development of a 3D silicon boss-membrane micro probe poses the problem of different stiffnesses in the Z- and X-, Y-directions. In general the ratio of these stiffnesses is approximately 30. A novel design (the so-called twin design) makes the achievement of equal stiffness possible in the three orthogonal probing directions of the 3D micro probe. The twin design is based on two parallel single silicon boss-membranes attached to each other. An analytical model for the calculation of the mechanical properties of the twin design is submitted. The developed analytical model describes the deformations of the membranes if the probe pin is deflected, and also the nonlinear mechanical properties of the twin design 3D micro probe. A comparison and an analysis of the experimental and theoretical results of the twin design investigation were carried out.