A novel method for building microsystems is presented and the performance of a particular electrical connector is evaluated in more detail. The method is based on flexible printed circuit boards made of polyimide (PI) foil. The building technique makes direct use of the good mechanical properties, which normally is not fully utilized, and the foil shape to made resilient, locking and self-supporting shell structures. These structural elements in combination with the functions normally found in flexible printed boards, conductors, from a versatile method for building microsystems. As a demonstrator, an operating micromotor based on mechanical stepping with piezoelectric elements will be presented. An important part in a microsystem is the electrical connections. These are normally attained by soldering, wire bonding or gluing, which all require additional processing steps. With the method presented here it is possible to make pressure connects where all connector functions are integrated in the PI film. Resilient tabs directly processed in the PI film are used as contact elements that press against e.g. a bump on a die. In this paper, both the forces achieved with the PI tabs and the resulting contact resistance is measured as a function of the tab deflection. The experiments are performed in a micromanipulator where a test probe is used to simulate a die bump. Geometrical demands on the microstructures and the limitations of the method are discussed.

Date Published: 8 October 1999
PDF: 10 pages
Proc. SPIE 3893, Design, Characterization, and Packaging for MEMS and Microelectronics, (8 October 1999); doi: 10.1117/12.368439

Published in SPIE Proceedings Vol. 3893:
Design, Characterization, and Packaging for MEMS and Microelectronics
Bernard Courtois; Serge N. Demidenko, Editor(s)