Batch Fabricated Rectangular Rod, Planar MEMS Quadrupole with Ion Optics

Applications

  • Gas chromatography
  • Mass spectrometry
  • Charged beam manipulation

Problem Addressed

Demand for rugged, small, light, inexpensive, and power efficient gas chromatography and mass spectrometry systems has recently driven the development of miniaturized mass filters. Producing these devices involves combinations of precision machining or micro-fabrication, and downstream manual assembly, all of which are costly. In particular, manual assembly of mass filters is expensive and inefficient, requiring individual tuning of each filter as each filter has unique misalignment conditions.

Technology

This technology describes a method for batch fabrication of MEMS quadrupoles, utilizing economy of scale for production and distribution.  The quadrupole mass filters produced by this method have a rectangular electrode cross section. The performance reduction caused by the use of non-circular electrodes is compensated for by operating these devices in high-order stability regions that yield higher resolution. 

The use of batch fabrication techniques allows very precise manufacture of the quadrupoles; because the quadrupoles are batch-fabricated, quadrupoles from the same batch share the same misalignment configuration, which means tuning of the quadrupoles in an analytical system can be more easily performed. The invention includes a series of etch steps, electrical insulator growth/deposition steps, wafer bonding steps, and metal deposition that can be utilized to fabricate the device.

Advantages

  • Miniaturization of quadrupole mass filters to enable portability and reduce power consumption.
  • Batch fabrication to produce low-cost quadrupoles mass filters in commercial quantities
  • Integrated optics, prefileters, drive signal processing, allow operating devices in high stability regions to meet performance requirements.