Development of 3-Dimentional Micro Probe using X-Ray Lithography and High-Strength Electroformed Ni

The rapid microminiaturization of LSI chips has encouraged the need for similarly microminiaturizing the probes of probe cards, the parts used to inspect IC chips. In response to this need, a method of producing 3-dimensional microprobes is devised by etching a substrate in advance and then performing X-ray lithography. By examining and optimizing each part of the process, we produced a 3-dimensional microprobe with the desired shape. Furthermore, we developed a high strength electroformed Ni, and applied to microprobes. The obtained microprobe was 18 gm wide and 50 mum thick, with a tip 185 mum high, consisting of both the spring part and the tip. The mechanical and electrical properties of the microprobe were estimated by measuring the contact force and contact resistance. The measurement showed satisfactory results: the contact force allowed a displacement magnitude as large as 80 mum, accompanied by a satisfactory contact force of 13 mN. In addition, the contact resistance exhibited low and stable values when contact was formed on an object made of Au exhibiting a contact force of 1 mN or more, demonstrating the high potential of the prototyped microprobes