Fabrication and mechanical characterization of micro electro mechanical system based vertical probe tips for micro pad measurements

Abstract

As a result of new developments in semiconductor technology, the number of pads per unit area is increasing and pad arrays are becoming irregular. Therefore, there is an increased need for a versatile probe card to address these issues. We developed a vertical micro electro mechanical system (MEMS) probe tip that is usable in a small pad (approximately 100 gm) and a two-dimensional pad array. The main process used to produce the tip was wafer bonding, silicon etching by deep reactive ion etcher (RIE) and electro-plating. The material of the electro-plated probe tip was an Ni-Co alloy. To optimize the design of the vertical probe tip, we designed various models and measured them in a micro compression and tensile tester. The structural analyses of the probe tip were accomplished using finite element method (FEM) and compared with actual measurement values. In this study, we demonstrated the potential of the vertical probe tip applied to a small area with the over drive (O.D.) of 10-40 mu m and the contact force of 1-8gf.