Membrane probe with pyramidal tips for a bare chip testing

Bare chips are used in multichip modules for high packaging density and high processing speed devices. Obtaining known good dies (KGD) is a significant problem in achieving high MCM yields. Therefore, a probing technique for bare chips with high reliability is a matter of importance. In order to achieve good contact properties at a low probing pressure, a new membrane probe with pyramidal tips is developed for bare chip testing. By using anisotropic etching of silicon, quadrangular pyramidal pits are formed as the cast of probe tips. By nickel plating these pits, nickel pyramidal tips with copper wiring are formed on the polyimide film. The silicon wafer cast is then dissolved completely by etching. This membrane probe is then attached to a socket. This pyramidal probe is vertically inserted into an aluminum pad. Contact resistance remained stable at 0.1-0.2 Ω