High sensitive structure and its fabrication process for MEMS fingerprint sensor to various fingers

Abstract

This paper describes a novel structure of MEMS (microelectromechanical systems) and its fabrication process on the surface of the MEMS fingerprint sensor that works as an interface between a finger and the sensor. In order to detect fingerprints, whether a finger is soft or hard, novel T-shaped protrusions are proposed. The structure was fabricated by etching a sacrificial layer on the cavity structure that has a pair of electrodes. Structural calculations and experimental measurements showed that the proposed sensor bends the electrode most efficiently. This enables fingerprint detection regardless of finger elasticity, and enhances sensitivity for various finger surface conditions.