Title :
A mold and transfer technique for lead-free fluxless soldering and application to MEMS packaging
Author :
Stark, Brian H. ; Najafi, Khalil
Author_Institution :
Michigan Univ., Ann Arbor, MI
Abstract :
This paper demonstrates a technique to premold and transfer lead-free solder balls for microelectrocmechanical systems (MEMS)/electronics packaging applications. A reusable bulk micromachined silicon wafer is used to mold a solder paste and remove excess flux prior to transfer to a host wafer that may contain released MEMS. This technique has been used to fabricate low temperature thin film MEMS vacuum packages. Long term (>5 months) reliability of these packages at room temperature and pressure is demonstrated through integrated Pirani gauges. These packages have survived over 600 hours in an autoclave (130degC, 85% RH, 2 atm) and more than 1300 temperature cycles (55degC to 125degC)
Keywords :
electronics packaging; micromachining; micromechanical devices; silicon; soldering; 130 C; 55 to 125 C; MEMS packaging; Pirani gauges; electronics packaging; fluxless soldering; lead-free solder balls; low temperature thin film; microelectrocmechanical systems; molding technique; reliability; reusable bulk micromachined silicon wafer; solder paste; transfer technique; vacuum packages; Electronics packaging; Environmentally friendly manufacturing techniques; Lead; Micromechanical devices; Nickel; Soldering; Temperature; Transistors; Vacuum technology; Wafer scale integration; Electroplated nickel films; solder sealing; thin film MEMS packaging; vacuum packaging;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2006.879812
