Chip Scale Micro Pump for Achieving High Vacuum

Technology #13724

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Cross-sectional view of inventive microvalve
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Inventors
Professor Akintunde Akinwande
Department of Electrical Engineering and Computer Science, MIT
External Link (www-mtl.mit.edu)
Carol Livermore
Department of Mechanical Engineering, MIT
External Link (meche.mit.edu)
Professor Martin Schmidt
Department of Electrical Engineering and Computer Science, MIT
External Link (orgchart.mit.edu)
Luis Fernando Velasquez-Garcia
MicroSystems Technology Laboratories, MIT
External Link (www-mtl.mit.edu)
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Single-use, permanently-sealable microvalve

US Patent 9,388,916
Publications
Browse Conference Publications > Electron Devices Meeting, 200 ... Help A Micro Ionizer for Portable Mass Spectrometers using Double-gated Isolated Vertically Aligned Carbon Nanofiber Arrays
Electron Devices Meeting, 2007. IEDM 2007. IEEE International, 843 - 846
Low-Voltage Field Ionization of Gases Up to Torr-Level Pressures Using Massive Arrays of Self-Aligned Gated Nanoscale Tips
IEEE Transaction on Electron Devices, Vol. 61, No. 5, 2014
Toward Amp-Level Field Emission With Large-Area Arrays of Pt-Coated Self-Aligned Gated Nanoscale Tips
IEEE Transaction on Electron Devices, Vol. 61, Issue 7, 2014
A Microionizer for Portable Mass Spectrometers Using Double-Gated Isolated Vertically Aligned Carbon Nanofiber Arrays
IEEE Transaction on Electron Devices, Vol. 58, No. 7, 2011
CNT-Based MEMS/NEMS Gas Ionizers for Portable Mass Spectrometry Applications
Journal of Microelectromechanical Systems, Vol. 19, No. 3, 2010
Fabrication of large arrays of high-aspect-ratio single-crystal silicon columns with isolated vertically aligned multi-walled carbon nanotube tips
Nanotechnology , Vol. 19, 2008

This compact chip scale pump achieves a high vacuum within a small chamber by using three stages to evacuate a chamber from atmospheric pressure to pressures of the order of 10^(-6) Torr.

Applications

  • Portable mass spectrometer
  • Vacuum nano-electronic amplifiers
  • Sensors, including atomic sensors based on spectroscopy of alkali atoms

Problem Addressed

Chip-scale systems such as sensors and analyzers that operate in a vacuum environment offer entirely new capabilities, such as rapid, portable detection of chemical warfare agents, but even with the potential they offer in portability, their practical application is limited by the size of the pumps that evacuate the air from the system. To date, the state of the art for evacuating chip-scale devices to high vacuum remains the macroscale vacuum pump. Chip-scale displacement pumps for vacuum pumping exist but are challenged to reach even the lower end of the low vacuum range. Plasma-driven chip-scale ion pumps have also been demonstrated for pumping down from atmospheric pressure, but their demonstrated base pressures remain in the low vacuum range.

Technology

The technology presents a solution to the chip scale pumping problem. The technology is a compact, multi-stage system where each stage utilizes a different technology to reduce the pressure from atmospheric to the required 10-6 Torr. The stages are as follows: (1) A displacement pump lowering the pressure from atmospheric (760 Torr) to the 10-30 Torr range, (2) a field ionization-driven pump that uses carbon nanotube (CNT) concentrators to ionize molecules lowers the pressure to 1-10 mTorr range, (3) an electron impact ionization-driven pump which ionizes molecules through electron collisions and brings down the pressure in the chamber down to 10-6 Torr.

This bare technology addresses the challenge posed by the limitation of pump size in chip-scale devices, but vacuum leakages reduce the longevity of the system. To fix this issue a micro-valve is used between the mechanical pump and the ion pump to increase the life expectancy of the system.

Advantages

  • Operating Ion pumps in the low pressure regime increases longevity substantially
  • Devices are fabricated for low cost production with tight specs
  • Minimum number of moving parts allows simplified and robust operation.
  • Series of pumps covers eight orders of magnitude of pressure