Organic Substrate Technologies for Fingerprint Sensors

Fingerprint sensor had a long history. With the mobile electronics security application being ushered in several years back, miniature and low-cost capacitive fingerprint sensors enjoyed an explosion growth. One technology to make such a low-cost, highly sensitive, high environment tolerating and reliable technology is to use organic substrate to construct sensing element. In this paper, several technologies are reviewed. They include Si based absolute capacitive sensors, film-based transcapacitive technology, organic substrate-based transcapacitive technology. To make highly sensitive substrate sensor, a newly invented architecture has been achieved with new photosensitive material in combination with traditional substrate manufacturing process, resulting the best performance at very low cost. Detailed manufacturing process and performance evaluation results will be presented.