Fabrication Technology of Microelectromechanical Systems Probe Chip Compatible with Standard Complementary Metal-Oxide-Semiconductor Process

摘要

In this paper, we present a rnicroelectromechanical systems (MEMS) probe chip compatible with the standard complementary metal-oxide-semiconductor (CMOS) process for testing RF devices and bumps. Using the standard CMOS process to fabricate in advance the multilayer interconnections between metal layers can conveniently facilitate the layout of the space transformer. In a limited area, we design two probe structures of meander shape and spiral shape. The probe cantilever consists of a CMOS membrane and the probe pitch is 150 μrn. The probe tip is fabricated successfully by electroless nickel (EN) plating process and the height of the probe tip approaches 106 μM. In particular, grinding and polishing processes are employed to level the rough surface of the probe tip so as to obtain uniform coplanarity. Moreover, In the photoresist SU-8 removal process, the plasma removal process is used instead of the stripper solutions to protect the probe tip from being damaged. The meander shape and spiral shape of probe cantilevers are successfully suspended by an inductively coupled plasma (ICP) etch system and the probe cantilevers have no warpage.