Title :
A Fracture Mechanics Description of Stress-Wave Repair in Stiction-Failed Microcantilevers: Theory and Experiments
Author :
Leseman, Zayd C. ; Koppaka, Sai B. ; Mackin, Thomas J.
Author_Institution :
New Mexico Univ., Albuquerque
Abstract :
Microcantilever beams are frequently utilized as sensor platforms in microelectromechanical system devices. These highly compliant surface-micromachined structures generally fail by adhering to the underlying substrate during processing or subsequent operation. Such failures, which are commonly known as ldquostictionrdquo failures, can be prevented or repaired in a number of ways, including low adhesion coatings, rinsing with low surface energy agents, and active approaches such as laser irradiation. Gupta [ J. Microelectromech. Syst. vol. 13, pp. 696-700, 2004] recently demonstrated that stress waves could be used to repair stiction-failed structures. This paper extends the work of Gupta by developing a fracture mechanics theory of the repair process and compares that theory with corresponding experiments. We show that: 1) incremental crack growth is associated with each laser pulse, the extent of which is directly related to the laser fluence; 2) repeated pulsing fully repairs all of the microcantilevers; and 3) a fracture mechanics model accurately predicts the observed experimental results. [1664].
Keywords :
cantilevers; laser beam machining; micromechanical devices; stiction; stress analysis; fracture mechanics; incremental crack growth; laser pulse; microcantilever beams; microelectromechanical system; sensor platforms; stiction failure; stiction-failed microcantilever; stress waves; stress-wave repair; surface-micromachined structures; Adhesives; Coatings; Laser modes; Laser theory; Microelectromechanical systems; Optical pulses; Sensor systems; Stress; Surface cracks; Surface emitting lasers; Fracture mechanics; laser; stiction; stress waves;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2006.883571