An Application of 3-D MEMS Packaging: Out-of-Plane Quadrupole Mass Filters

Massachusetts Inst. of Technol., Cambridge, MA
Journal of Microelectromechanical Systems (Impact Factor: 1.75). 01/2009; 17(6):1430 - 1438. DOI: 10.1109/JMEMS.2008.2006769
Source: IEEE Xplore


This paper reports the design, fabrication, and characterization of low-cost out-of-plane quadrupole mass filters that use commercially available dowel pins as electrode rods. The quadrupoles implement a 3-D MEMS packaging technology that relies on deep-reactive ion etching (DRIE)-patterned deflection springs for alignment. Quadrupoles with rod diameter ranging from 0.25 to 1.58 mm and aspect ratio of 30 to 60 were built and tested at RF frequencies of 1.44, 2.0, and 4 MHz. Assembled devices operated in the first stability region achieved a maximum mass range of 650 amu, while a minimum half-peak width of 0.4 amu at mass 28 was obtained in the second stability region. Operation in the second stability region provides a means to higher resolution, smoother peaks, and removed peak splitting at the expense of transmission. The ultimate resolution of the reported quadrupoles is also discussed.

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Available from: L. F. Velásquez-García
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    • "The rods were supported in a silicon frame, fabricated by deep reactive ion etching (DRIE) of bonded silicon-on-insulator (BSOI) material . Using a similar approach but with an out-of-plane geometry , a mass range of m/z = 614 and an estimated resolution of m/Δm ≈ 13 at 10% peak height was demonstrated at the Massachusetts Institute of Technology [86]. Recently, a new silicon-on-glass design from Microsaic Systems incorporating a prefilter achieved a mass range of m/z = 1200 and a resolution of m/Δm ≈ 150 at 10% peak height [87]. "
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