Fabrication and characteristics of MEMS vertical type probe tip for micro sized pads measurement

In this research we proposed, designed, fabricated, and measured a novel Micro Electro Mechanical System (MEMS) based vertical probe tips which differs from conventional cantilever probe tips. The main idea of the vertical probe design was how to distribute the total forces vertically concentrated on the probe tip in measuring semiconductor devices. To solve the problem, we designed the vertical probe tip with meander structure which could provide enough displacements so that the vertical probe tips could distribute the forces acting on the tips. The structural analyses of the probe tip were accomplished using finite element method (FEM) and compared with actual measurement values. The primary fabrication processes were surface micromachining, wafer bonding technology, and electroplating. The material of the electro-plated probe tip was an Ni-Co alloy. In this study, we demonstrated the potential of the vertical probe tip that could apply to a small area with the over drive (O.D.) of 10-40 μm and the contact force of 1-8 gf. The measured contact resistance was less than 2 Ω and little noise was observed.