An Out-of-Plane MEMS Quadrupole for a Portable Mass Spectrometer

This paper reports the design, fabrication and characterization of a hand-assembled out-of-plane MEMS quadrupole mass filter. The device utilizes a 3D packaging technology that relies on mesoscale DRIE-patterned deflection springs for assembly. Microfabricated quadrupoles with 1.58 mm down to 0.56 mm diameter rods and 30 to 60 aspect ratios were built and tested. The quadrupoles were characterized in the first stability region at an RF frequency of 1.44 MHz, using a constant peak width sweeping method, obtaining a dynamic range of 650 amu and a half-peak width of 2 amu. Better performance is expected if a higher RF frequency is used.